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[Music kucheza]

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>> DAVID J. Malan: zote haki, hii ni CS50.

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Na hii ni wiki moja.

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Hivyo kukumbuka kwamba mara ya mwisho katika wiki sifuri,
sisi ililenga katika kufikiri computational.

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Na sisi zilianza kutoka kwamba kwa
Scratch, programu graphical

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lugha kutoka kwa marafiki zetu
katika MIT Media Lab.

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>> Na kwa Scratch, hatukufanya kuchunguza
mawazo kama kazi, na masharti,

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na tanzi, na vigezo, na hata
matukio, na nyuzi, na zaidi.

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Na leo, tunakwenda
kuendelea kutumia mawazo hayo,

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na kwa kweli kuwapeleka kwa
nafasi, lakini kutafsiri yao

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kwa lugha nyingine inajulikana kama C. Sasa,
C ni lugha zaidi ya jadi.

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Ni ngazi ya chini
lugha, kama wewe.

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>> Ni rena textual.

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Na hivyo katika mtazamo wa kwanza, ni
wote kwenda kuangalia badala cryptic

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kama wewe sijawahi iliyowekwa mbele.

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Tunakwenda kuwa na
nusu colons, na mabano,

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na curly braces, na zaidi.

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Lakini kutambua kwamba hata
ingawa syntax ni

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kuhusu kuangalia kidogo usio wa kawaida
kwa wengi wenu, kuona nyuma kwamba.

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Na kujaribu kuona mawazo
kwamba ni kweli, utambuzi,

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kwa sababu hapa katika wiki moja nini
tutaweza kuanza kufanya ni kulinganisha,

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awali, Scratch dhidi C.

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>> Hivyo, kwa mfano, kukumbuka kuwa wakati sisi
kutekelezwa kwanza ya mipango yetu

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mara ya mwisho, tulikuwa na kuzuia kwamba inaonekana
kitu kidogo kama hii wakati

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bendera ya kijani clicked, na kisha tulikuwa na
vipande moja au zaidi puzzle chini yake,

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katika kesi hii, kusema, hello dunia.

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Hivyo, kwa kweli, katika Scratch,
wakati mimi bonyeza bendera ya kijani kwamba

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kuendesha programu yangu, hivyo
kusema, haya ni

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vitalu kwamba kupata kunyongwa, au kukimbia.

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Na, hasa, Scratch
Alisema, hello, dunia.

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>> Sasa, mimi naweza kuwa maalum
maneno tofauti hapa.

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Lakini tutaona kwamba, kwa hakika, wengi
ya blocks-- hizi na kwa kweli,

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katika C functions-- wengi wanaweza kuwa
parametrized au umeboreshwa

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kufanya mambo mbalimbali.

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Kwa kweli, katika C kama sisi
unataka kubadilisha, sasa,

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mpango huu Scratch
kwa lugha hii nyingine,

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tunakwenda kuandika
kitu kidogo kama hii.

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>> Ni kweli kwamba, kuna baadhi ya usio wa kawaida
syntax huko uwezekano mkubwa, int,

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na mabano, na utupu.

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Lakini printf-- ingawa wewe ungekuwa
kufikiri ingekuwa tu kuwa magazeti.

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Lakini magazeti ina maana magazeti
mpangilio, kama tutaweza hivi karibuni kuona.

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Hii literally magazeti
kwa screen chochote

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ni ndani ya mabano hizo, ambayo
bila shaka katika kesi hii ni, hello dunia.

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>> Lakini utasikia taarifa nyingine
syntax, baadhi quotes mbili,

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kwamba mabano mwishoni,
nusu koloni na kadhalika.

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Hivyo kuna kidogo ya uendeshaji,
hivyo kusema, wote cognitively

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na syntactically, kwamba tunakwenda
kuwa na kukumbuka kabla ya muda mrefu.

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Lakini kutambua kwamba pamoja na mazoezi,
hii itakuwa kuanza kuruka nje saa wewe.

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>> Kwa kweli, hebu kuzingatia kwamba moja
kazi specifically-- katika kesi hii,

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kusema hello dunia.

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Hivyo kusema ni kazi.

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Jambo dunia ni parameter yake,
au hoja, customization yake.

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>> Na yanayolinagana katika C ni tu
kwenda kuwa mstari huu moja hapa,

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ambapo printf ni sawa na, kusema,
mara mbili alinukuliwa kamba, hello

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dunia ni sawa, bila shaka,
kwa nini katika sanduku nyeupe huko.

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Na backslash n, ingawa kidogo
ajabu na kukaa mbali na Scratch,

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tu ni kwenda kuwa na athari tutaweza
kuona katika kompyuta, kama Mac yangu au PC,

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ya kusonga tu
mshale wa mstari wa pili.

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Ni kama kupiga
Kuingia kwenye keyboard yako.

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>> Hivyo tutaweza kuona kwamba tena kabla ya muda mrefu.

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Lakini kwanza, hebu tuangalie hii
mfano mwingine katika kesi ya loops.

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Tulikuwa na hii milele kitanzi mara ya mwisho,
ambayo ilikuwa mfululizo wa vipande puzzle

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kwamba alifanya kitu literally
forever-- katika kesi hii,

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kusema, hello dunia, hello dunia,
hujambo dunia, hello dunia.

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Hivyo ni usio kitanzi kwa kubuni.

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>> Katika C, kama tunataka kutekeleza hili
wazo moja, tupate tu kufanya hivyo.

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Wakati wa kweli, printf hujambo world-- sasa
wakati, tu semantically, aina ya

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conjures up wazo la kufanya
kitu tena, na tena, na tena,

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na kwa muda gani?

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Naam, true-- kukumbuka kwamba
kweli ni tu juu au moja.

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>> Na kweli ni, bila shaka, kweli daima.

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Hivyo ni aina ya maana
Kauli tu kusema kweli.

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Lakini kwa kweli, hii ni makusudi,
kwa sababu kama kweli ni kweli tu daima,

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kuliko wakati kweli ina maana tu,
kama kidogo moja kwa moja,

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kwamba mistari ifuatayo ya kanuni
katika kati ya wale braces curly

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lazima tu kutekeleza tena, na tena,
na tena, na kamwe kweli kuacha.

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>> Lakini kama huna wanataka yako
kitanzi na kuacha, kama sisi

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alivyofanya mara ya mwisho na kitu kama
huu, kurudia kufuatia mara 50,

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katika C tunaweza kufanya hivyo kwa nini
kuitwa kwa ajili ya loop-- keyword

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kutokuwa wakati, lakini kwa.

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Na kisha tuna baadhi syntax mpya hapa,
na int i sawa 0, i chini ya 50,

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i ++.

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Na tutaweza kuja nyuma na kwamba.

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Lakini hii ni tu jinsi sisi ingekuwa
kutafsiri seti ya vitalu Scratch

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kwa seti ya mistari C ya kanuni.

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>> Wakati huo huo, kufikiria vigezo.

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Na, kwa kweli, sisi tu
aliona moja wakati iliyopita.

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Na katika kesi ya Scratch, kama sisi
alitaka kutangaza variable kuitwa i

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kwa i kuwa integer, idadi tu,
na tunataka kuweka kwa baadhi ya thamani,

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tunataka kutumia machungwa huu
kuzuia here-- kuweka i kwa 0.

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>> Na tutaweza kuona leo na
zaidi, tu kama wiki iliyopita,

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programmers kufanya karibu kila mara
kuanza kuhesabu kutoka sifuri, kwa kweli

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kwa mkataba.

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Lakini pia kwa sababu wanakumbuka kutoka
mjadala wetu wa binary,

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idadi ndogo unaweza
kuwakilisha na idadi yoyote ya bits

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ni kwenda tu kuwa 0 yenyewe.

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Na hivyo tutaweza ujumla kuanza
initializing hata vigezo yetu kwa 0.

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>> Na katika C kufanya hivyo,
tunakwenda kusema int

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kwa integer, i tu kwa mkataba.

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Mimi naweza kuwa na kuitwa kutofautiana hii
kitu chochote nataka, kama vile katika Scratch.

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Na kisha ni sawa na 0 tu chukueni
thamani 0 kutoka kulia

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na kuiweka katika kutofautiana, au
kuhifadhi kontena huko, upande wa kushoto.

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Na nusu koloni kama tutaweza see-- na
tumeona chache ya already-- hizi

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ina maana tu mwisho wa mawazo.

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Kuendelea kwa kufanya kitu kingine
juu ya mistari kwamba kufuata.

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>> Sasa, nini kuhusu maneno Boolean?

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Kumbuka kwamba katika Scratch,
hawa walikuwa maneno

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ambayo ni aidha kweli
au maswali false--,

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kwa kweli, kwamba ni ama kweli au uongo.

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Hivyo katika kesi ya Scratch, tupate
kuuliza swali rahisi kama hii,

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ni i chini ya 50?

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Hivyo i, tena, ni integer.

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Labda tunayatumia
katika mpango Scratch

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kuweka wimbo wa alama
au kitu kama hicho.

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Hivyo hii syntax hapa katika Scratch
ina maana tu, ni i chini ya 50?

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Naam, nashiriki, kuna kitu
rahisi katika C. Na kutafsiri,

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huu tunataka tu kusema i chini
ya 50, kwa kutumia ufunguo ukoo

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kwenye keyboard yako.

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>> Wakati huo huo, kama alitaka
kusema kitu zaidi ya jumla,

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kama, vizuri, ni x chini ya y ambapo kila
ya x na y ni wenyewe vigezo?

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Tunaweza kufanya kitu kimoja
katika C, hivyo muda mrefu kama tumekuwa

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umba vigezo hivi tayari.

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Na tutaweza kuona jinsi ya
kufanya hivyo kabla ya muda mrefu.

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Tunataka tu kusema x chini ya y.

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>> Hivyo wewe ni mapya ya
kuona baadhi yanayofanana.

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Na wale folks ambaye alifanya
Scratch walikuwa na shaka

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aliongoza kwa baadhi ya mawazo haya ya msingi.

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Na utaona aina hii ya
syntax katika wengi languages--

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sio tu Scratch, si
tu C, lakini chatu,

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na JavaScript, na
lugha nyingine bado.

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>> Hebu fikiria kujenga mwingine
kutoka C, dhana ya hali,

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kufanya kitu kwa masharti.

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Kama kitu ni kweli, kufanya hivyo.

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Kama kitu kingine ni kweli, kufanya hivyo.

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Ni aina ya programu
sawa na mgawanyiko katika barabara.

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Labda ni njia mbili uma,
njia tatu uma, au zaidi.

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Na katika Scratch, tupate kuwa
kuonekana kitu kama hiki.

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>> Hivyo hii moja moja kubwa.

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Lakini fikiria jamaa
unyenyekevu wa mantiki.

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Kama x ni chini ya y, basi sema x ni chini
kuliko y, mwingine kama x ni mkubwa kuliko y,

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basi sema x ni mkubwa kuliko y.

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Na kisha, kifikra, kama
unadhani nyuma Scratch

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au tu binadamu yako mwenyewe Intuition,
vizuri, kama x si mkuu zaidi kuliko y, na x

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si chini ya y, basi bila shaka
x ni kwenda kuwa sawa na y.

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Hivyo katika kesi hii, na nesting
wale vitalu Scratch,

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tunaweza kufikia tatu
njia uma katika barabara?

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>> Wakati huo huo, kama tunataka
kufanya hivyo katika C, ni arguably

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inaonekana simpler-- kidogo angalau
mara moja kupata ukoo na syntax.

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Kama x ni chini ya y,
printf x ni chini ya y.

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Mwingine kama x ni mkubwa kuliko y,
printf x ni mkubwa kuliko y.

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Mwingine printf x ni sawa na y-- na,
tena, na wale backslash mwisho tu

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kwa wale mistari mpya ili kwamba kama wewe
kweli mbio aina hii ya mpango

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ingekuwa tu hoja
mshale hatimaye

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mstari wa pili ya screen.

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>> Sasa, wakati huo huo Scratch alikuwa nyingine
makala ya kisasa zaidi, tu

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baadhi ya ambayo tunakwenda
awali hoja juu ya dunia ya C.

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Na mmoja wao alikuwa
aitwaye orodha katika Scratch.

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Na hii ilikuwa maalum
aina ya kutofautiana kwamba

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kuruhusiwa wewe kuhifadhi vitu mbalimbali
katika nyuma, na nyuma, na nyuma, na nyuma.

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>> Katika C, haina
orodha, per se, lakini kitu

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kwamba kwa ujumla zaidi
aitwaye arrays, ingawa tutaweza

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kurudi baadaye muhula huu
kwa kuangalia kitu

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aitwaye orodha, au kweli orodha wanaohusishwa.

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Lakini kwa sasa, karibu
sawa katika C kwa ajili yetu

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ni kwenda kuwa kitu
aitwaye safu.

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Na safu ni tu
maalum aina ya kutofautiana

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kwamba utapata kuhifadhi data
nyuma, na nyuma, na nyuma, kwa nyuma.

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>> Na kwa kweli, katika Scratch,
kama sisi alitaka kupata

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sehemu ya kwanza ya safu au
list-- na mimi nina kwenda kwa simu yake,

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kwa mkataba huo, argv, hoja
vector, lakini zaidi juu ya kwamba kabla ya muda mrefu.

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Kama mimi nataka kupata saa kipengele kwanza
ya argv, katika ulimwengu wa Scratch

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wewe kweli kufanya kawaida
kuanza kuhesabu kutoka 1.

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>> Na hivyo mimi ili kupata item 1 ya argv.

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Hiyo tu jinsi MIT kutekelezwa
dhana ya orodha.

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Lakini katika C, Mimi nina kwenda
zaidi tu kusema tu, argv,

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ambayo tena ni jina la yangu
list-- au kuwa wazi, safu.

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Na kama nataka kwanza
vipengele, mimi nina kwenda

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kutumia mabano mraba, ambayo wewe
wanaweza mara nyingi hutumika chini ya keyboard.

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>> Lakini 0 tu ina maana, kupata yangu ya kwanza.

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Hivyo juu ya tukio na kama
wakati hupita, tunakwenda

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00:08:42,160 --> 00:08:44,570
kabla ya kuanza kuona dichotomies haya
kati Scratch na C,

184
00:08:44,570 --> 00:08:46,070
ambapo Scratch anatumia moja.

185
00:08:46,070 --> 00:08:47,670
Sisi katika C kutumia 0 hapa.

186
00:08:47,670 --> 00:08:49,420
Lakini utasikia haraka kuona
mara tu kuelewa

187
00:08:49,420 --> 00:08:52,920
Misingi ya kila lugha, kwamba
mambo haya kuanza kupata wote zaidi

188
00:08:52,920 --> 00:08:56,860
ukoo kwa njia ya mazoezi na mazoezi.

189
00:08:56,860 --> 00:08:59,700
>> Basi hebu kweli sasa tuangalie mpango.

190
00:08:59,700 --> 00:09:04,031
Hapa watakuwa wa kwanza wa C yetu
chanzo kanuni kwa ajili ya programu kamili.

191
00:09:04,031 --> 00:09:06,280
Na mpango tunakwenda
kutoa kwa kuzingatia

192
00:09:06,280 --> 00:09:09,340
ni moja hiyo ni sawa
kwa kuwa mapema Scratch kipande.

193
00:09:09,340 --> 00:09:13,210
>> Hivyo katika hapa, tuna nini
arguably C mpango rahisi

194
00:09:13,210 --> 00:09:15,410
unaweza kuandika kwamba
kweli hana kitu.

195
00:09:15,410 --> 00:09:18,250
Sasa, tutaangalia siku za nyuma,
kwa sasa, ina ni pamoja na,

196
00:09:18,250 --> 00:09:21,190
kiwango io.h, na hizi angle
mabano, na int, na batili,

197
00:09:21,190 --> 00:09:22,840
na braces curly, na kadhalika.

198
00:09:22,840 --> 00:09:25,390
>> Na hebu tu kuzingatia
je nini hasa intuitively,

199
00:09:25,390 --> 00:09:26,860
inaweza kuruka nje saa wewe tayari.

200
00:09:26,860 --> 00:09:30,300
Kwa kweli, kuu, sijui
lazima kujua hii ni nini,

201
00:09:30,300 --> 00:09:34,580
lakini kiasi kama Scratch alikuwa na kwamba wakati
bendera ya kijani clicked puzzle kipande,

202
00:09:34,580 --> 00:09:39,070
hivyo haina C kama lugha ya programu
kuwa na kipande kuu ya kificho kwamba

203
00:09:39,070 --> 00:09:43,380
anapata kunyongwa na default. Na kwa kweli,
ni literally kwenda kuitwa kuu.

204
00:09:43,380 --> 00:09:44,720
>> Hivyo kuu ni kazi.

205
00:09:44,720 --> 00:09:48,720
Na ni kazi maalum ambayo ipo
katika C kwamba wakati wewe kukimbia mpango,

206
00:09:48,720 --> 00:09:52,720
ni kuu kwamba anapata inayoendeshwa na
default. Katika ulimwengu wa Scratch,

207
00:09:52,720 --> 00:09:56,970
ilikuwa ni kawaida wakati kijani bendera
clicked kwamba got kukimbia na default.

208
00:09:56,970 --> 00:10:01,130
>> Wakati huo huo, tumeona hii kabla,
printf au magazeti mpangilio, hiyo ni

209
00:10:01,130 --> 00:10:05,620
kwenda kuwa kazi ambayo inakuja na
C, pamoja na rundo zima la wengine,

210
00:10:05,620 --> 00:10:10,140
kwamba mapenzi kutoka muda na wakati
tena, ili kufanya hasa

211
00:10:10,140 --> 00:10:12,450
kama jina lake anapendekeza, magazeti kitu.

212
00:10:12,450 --> 00:10:13,500
Je, tunataka magazeti?

213
00:10:13,500 --> 00:10:15,770
Naam, tutaweza kuona kwamba
na wahusika enclosing

214
00:10:15,770 --> 00:10:18,680
kama these-- dunia hello,
backslash n katika quotes mbili,

215
00:10:18,680 --> 00:10:23,040
tunaweza kujua printf hasa
nini magazeti juu ya screen.

216
00:10:23,040 --> 00:10:26,430
>> Lakini ili kufanya
kwamba, sisi kwa bahati mbaya

217
00:10:26,430 --> 00:10:30,010
haja ya kuchukua kitu ambacho ni
tayari cryptic kwa sisi binadamu,

218
00:10:30,010 --> 00:10:34,510
lakini angalau ni kiasi fulani readable--
mkali ni pamoja na, kiwango io.h, int,

219
00:10:34,510 --> 00:10:39,340
kuu, utupu, printf, wote wa kichawi
incantations sisi tu kuona kwenye screen.

220
00:10:39,340 --> 00:10:42,470
Lakini sisi kweli kuwa
kwenda zaidi arcane bado.

221
00:10:42,470 --> 00:10:47,140
Sisi kwanza haja ya kutafsiri kanuni
kwamba sisi kuandika katika mashine kanuni.

222
00:10:47,140 --> 00:10:51,370
Na kukumbuka kutoka wiki iliyopita kuwa mashine,
angalau ndio tunajua hapa,

223
00:10:51,370 --> 00:10:54,450
mwisho wa siku tu
kuelewa zeros na ndio.

224
00:10:54,450 --> 00:10:58,100
>> Na Mungu wangu, kama tulikuwa na kuandika haya
zeros na ndio kwa kweli mpango,

225
00:10:58,100 --> 00:11:01,260
ingekuwa kwa haraka sana,
kuchukua furaha nje ya kitu chochote.

226
00:11:01,260 --> 00:11:05,150
Lakini zinageuka, per wiki iliyopita,
kuwa mipangilio hii ya zeros na ndio

227
00:11:05,150 --> 00:11:06,400
tu na maana ya pekee.

228
00:11:06,400 --> 00:11:08,500
Katika mazingira fulani,
wapate maana idadi.

229
00:11:08,500 --> 00:11:11,840
>> Katika mazingira fulani, wapate maana
barua, au rangi, au idadi yoyote

230
00:11:11,840 --> 00:11:14,710
ya uchukuaji nyingine huko juu.

231
00:11:14,710 --> 00:11:18,450
Lakini kama vile kompyuta yako ina
CPU, Central Processing Unit,

232
00:11:18,450 --> 00:11:20,390
au bongo ndani ya kompyuta yako.

233
00:11:20,390 --> 00:11:22,240
Ni kawaida Intel
ndani, kwa sababu hiyo ni

234
00:11:22,240 --> 00:11:24,900
moja ya makampuni makubwa
kwamba inafanya CPUs kwa ajili ya kompyuta.

235
00:11:24,900 --> 00:11:28,910
>> Naam, Intel CPUs na wengine
tu wameamua mapema

236
00:11:28,910 --> 00:11:33,970
kwamba baadhi ya mifumo ya zeros na
ndio itakuwa na maana mambo maalum.

237
00:11:33,970 --> 00:11:37,040
chati fulani ya zeros na ndio
itakuwa na maana, magazeti huu kwa screen,

238
00:11:37,040 --> 00:11:39,710
au kuongeza namba hizi mbili, au
Ondoa namba hizi mbili,

239
00:11:39,710 --> 00:11:43,310
au hoja kipande cha data kutoka
kumbukumbu ya kompyuta yangu zaidi ya hapa,

240
00:11:43,310 --> 00:11:47,870
au idadi yoyote ya ngazi nyingine ya chini sana,
lakini hatimaye muhimu, shughuli.

241
00:11:47,870 --> 00:11:53,022
Lakini, nashiriki, sisi binadamu si kwenda
haja ya kujua kiwango hiki cha habari.

242
00:11:53,022 --> 00:11:56,230
Hakika, tu kama mara ya mwisho, ambapo sisi
yanayotumika tena, na tena, na tena,

243
00:11:56,230 --> 00:11:58,930
jengo kutoka ngazi ya chini sana
primitives kama zeros na ndio

244
00:11:58,930 --> 00:12:01,160
na dhana ngazi za juu
kama idadi, na barua,

245
00:12:01,160 --> 00:12:04,330
na rangi, na zaidi,
sisi pia tunaweza kama programmers

246
00:12:04,330 --> 00:12:07,080
kusimama juu ya mabega ya
wengine ambao wamekuja mbele yetu

247
00:12:07,080 --> 00:12:11,260
na kutumia programu ambayo wengine
watu wameandika kabla us--

248
00:12:11,260 --> 00:12:14,340
ambazo ni mipango aitwaye compilers.

249
00:12:14,340 --> 00:12:17,770
>> C ni lugha ambayo
ni kawaida ulioandaliwa,

250
00:12:17,770 --> 00:12:22,130
ambayo ina maana waongofu kutoka
chanzo kanuni kwa mashine code.

251
00:12:22,130 --> 00:12:25,230
Hasa, nini maana ya hii
ni kwamba kama nimepata chanzo wako

252
00:12:25,230 --> 00:12:29,530
kificho kwamba wewe mwenyewe kuandika, kama sisi hivi karibuni
mapenzi katika muda tu juu ya screen,

253
00:12:29,530 --> 00:12:33,140
na unataka kubadilisha
hatimaye kwa mashine code--

254
00:12:33,140 --> 00:12:37,100
wale zeros na ndio kwamba
tu ya Mac au PC yako

255
00:12:37,100 --> 00:12:41,230
understands-- nimepata kwanza
kulisha kwamba kanuni chanzo katika kama

256
00:12:41,230 --> 00:12:46,340
pembejeo kwa maalum
programu inayoitwa compiler,

257
00:12:46,340 --> 00:12:48,974
pato la ambayo sisi
wataona ni mashine kanuni.

258
00:12:48,974 --> 00:12:51,890
Na kwa kweli, mara ya mwisho sisi aliyesema
kuhusu, kwa kweli, mwisho wa siku,

259
00:12:51,890 --> 00:12:52,610
kutatua tatizo.

260
00:12:52,610 --> 00:12:53,360
Nimepata pembejeo.

261
00:12:53,360 --> 00:12:54,318
Na nimepata mazao.

262
00:12:54,318 --> 00:12:56,560
Na nimepata aina fulani
ya algorithm katikati.

263
00:12:56,560 --> 00:12:59,830
>> Algorithms unaweza hakika kuwa
kutekelezwa katika programu,

264
00:12:59,830 --> 00:13:02,900
kama tuliona na pseudocode wiki iliyopita
na kama tutaweza kuona na kanuni halisi

265
00:13:02,900 --> 00:13:03,490
wiki hii.

266
00:13:03,490 --> 00:13:06,430
Na hivyo compiler kweli tu
ina seti ya algorithms ndani ya

267
00:13:06,430 --> 00:13:10,060
yake ili kujua jinsi ya
kubadilisha maneno maalum,

268
00:13:10,060 --> 00:13:12,180
kama kuu, na printf,
na wengine kwamba sisi tu

269
00:13:12,180 --> 00:13:17,620
aliona katika mifumo ya zeros na
wale ambao Intel ndani na wengine CPUs

270
00:13:17,620 --> 00:13:20,020
kweli anaelewa.

271
00:13:20,020 --> 00:13:22,460
Hivyo ni jinsi gani sisi kufanya hili?

272
00:13:22,460 --> 00:13:24,470
Ambapo tunapata compiler?

273
00:13:24,470 --> 00:13:26,400
>> Wengi wetu hapa na Mac au PC.

274
00:13:26,400 --> 00:13:29,152
Na wewe ni mbio Mac OS, au
Madirisha, au Linux, au Solaris,

275
00:13:29,152 --> 00:13:30,860
au idadi yoyote ya wengine
mifumo ya uendeshaji.

276
00:13:30,860 --> 00:13:32,568
Na, kwa hakika, tunaweza
kwenda nje kwenye mtandao

277
00:13:32,568 --> 00:13:35,710
na download compiler
kwa Mac au PC yako

278
00:13:35,710 --> 00:13:37,360
kwa mfumo wako hasa uendeshaji.

279
00:13:37,360 --> 00:13:39,617
Lakini sote tungekuwa juu ya
kurasa tofauti, hivyo kusema.

280
00:13:39,617 --> 00:13:41,450
Tunatarajia kuwa kidogo
mazungumzo mbalimbali.

281
00:13:41,450 --> 00:13:43,210
Na mambo bila kufanya kazi wote ni sawa.

282
00:13:43,210 --> 00:13:45,280
Na, kwa hakika, siku hizi
wengi wetu hawatumii

283
00:13:45,280 --> 00:13:47,516
programu kwamba anaendesha tu juu ya Laptops wetu.

284
00:13:47,516 --> 00:13:49,390
Badala yake, sisi kutumia kitu
kama browser kwamba

285
00:13:49,390 --> 00:13:52,930
inaruhusu sisi kupata mtandao msingi
maombi katika wingu.

286
00:13:52,930 --> 00:13:55,630
Na baadaye hii muhula,
sisi kufanya hasa kwamba.

287
00:13:55,630 --> 00:13:59,660
Sisi kuandika maombi au
programu kwa kutumia code-- si C,

288
00:13:59,660 --> 00:14:02,860
lakini lugha nyingine kama chatu na
JavaScript-- kwamba kukimbia katika hilo wingu.

289
00:14:02,860 --> 00:14:05,860
>> Na kwa kufanya hivyo, sisi wenyewe
wakati wa muhula

290
00:14:05,860 --> 00:14:11,890
kweli kutumia wingu makao
mazingira inayojulikana kama CS50 IDE.

291
00:14:11,890 --> 00:14:16,030
Hii ni programu mtandao msingi
mazingira, au maendeleo jumuishi

292
00:14:16,030 --> 00:14:20,610
mazingira, IDE, hiyo kujengwa atop baadhi
wazi chanzo programu inayoitwa Cloud 9.

293
00:14:20,610 --> 00:14:22,966
Na tumekuwa alifanya baadhi ya ufundishaji
simplifications yake

294
00:14:22,966 --> 00:14:25,840
ili kuficha baadhi ya vipengele katika
wiki ya kwanza kwamba hatuna haja,

295
00:14:25,840 --> 00:14:27,770
baada ambayo unaweza
yatangaza yao na kufanya zaidi

296
00:14:27,770 --> 00:14:29,400
kitu chochote unataka na mazingira.

297
00:14:29,400 --> 00:14:32,470
>> Na inaruhusu sisi, pia, kwa
kabla ya kufunga programu fulani.

298
00:14:32,470 --> 00:14:35,330
Mambo kama kinachojulikana CS50
maktaba, ambayo tutaweza hivi karibuni kuona

299
00:14:35,330 --> 00:14:39,210
hutoa sisi katika C na baadhi
utendaji ya ziada.

300
00:14:39,210 --> 00:14:44,392
Hivyo kama wewe kwenda kwa, hatimaye, CS50.io,
wewe utakuwa ilisababisha kuingia katika,

301
00:14:44,392 --> 00:14:46,350
na mara moja wewe kufanya na kujenga
akaunti kwa ajili ya bure,

302
00:14:46,350 --> 00:14:52,150
utakuwa na uwezo wa kupata
mazingira kwamba inaonekana kabisa kama hii.

303
00:14:52,150 --> 00:14:53,760
>> Sasa, hii ni katika hali ya chaguo-msingi.

304
00:14:53,760 --> 00:14:55,650
Kila kitu ni nzuri na
mkali juu ya screen.

305
00:14:55,650 --> 00:14:57,941
Wengi wetu wana tabia ya
kazi ya CS50 kipande hiyo ni

306
00:14:57,941 --> 00:14:59,150
kabisa marehemu katika usiku.

307
00:14:59,150 --> 00:15:02,400
Na hivyo baadhi yenu wanaweza kupendelea
kugeuka ndani mode usiku, hivyo kusema.

308
00:15:02,400 --> 00:15:05,550
>> Lakini, hatimaye, nini wewe
kwenda kuona ndani ya CS50 IDE

309
00:15:05,550 --> 00:15:08,340
ni tatu tofauti areas--
eneo juu ambapo kushoto

310
00:15:08,340 --> 00:15:12,604
mafaili yako ni kwenda kuwa katika
wingu, eneo juu ya haki juu

311
00:15:12,604 --> 00:15:14,270
ambapo kanuni yako ni kwenda kuwa editable.

312
00:15:14,270 --> 00:15:16,650
Wewe utakuwa na uwezo wa kufungua
tabo mtu binafsi kwa ajili ya mpango wowote

313
00:15:16,650 --> 00:15:19,670
kwamba kuandika muhula huu ndani ya
ya kwamba kona ya juu kulia.

314
00:15:19,670 --> 00:15:23,070
Na kisha zaidi arcanely,
na bado kwa nguvu,

315
00:15:23,070 --> 00:15:26,610
ni kwenda kuwa jambo hili katika
chini inayojulikana kama dirisha terminal.

316
00:15:26,610 --> 00:15:29,450
>> Hii ni shule ya zamani
Amri Line Interface,

317
00:15:29,450 --> 00:15:32,240
au CLI, ambayo inaruhusu
wewe kutekeleza amri

318
00:15:32,240 --> 00:15:35,260
juu ya computer-- katika kesi hii,
kompyuta katika cloud--

319
00:15:35,260 --> 00:15:39,090
kufanya mambo kama kukusanya code yako
kutoka chanzo kanuni kwa mashine code,

320
00:15:39,090 --> 00:15:43,600
kuendesha programu yako, au kuanza yako
mtandao wa kompyuta, au hii kufikia hifadhidata yako,

321
00:15:43,600 --> 00:15:47,454
na idadi yoyote ya mbinu nyingine
kwamba tutaweza kuanza kutumia kabla ya muda mrefu.

322
00:15:47,454 --> 00:15:49,370
Lakini kufika huko, tuko
kwenda kweli kuwa

323
00:15:49,370 --> 00:15:51,240
kwenda online na kuanza kucheza.

324
00:15:51,240 --> 00:15:54,399
Na kwa kufanya hivyo, hebu kwanza
kuanza kuchezea kuu,

325
00:15:54,399 --> 00:15:55,940
na kuandika sehemu kuu ya mpango.

326
00:15:55,940 --> 00:15:59,170
Na hebu kutumia kwamba kazi
printf, ambayo sisi kutumika hapo awali,

327
00:15:59,170 --> 00:16:01,050
tu kusema kitu.

328
00:16:01,050 --> 00:16:04,910
>> Hivyo hapa mimi tayari ndani ya CS50 IDE.

329
00:16:04,910 --> 00:16:05,930
Nimekuwa watumiaji katika mapema.

330
00:16:05,930 --> 00:16:07,360
Na mimi full kupimwa dirisha.

331
00:16:07,360 --> 00:16:09,670
Na hivyo, hatimaye, wewe
pia katika matatizo Ujio

332
00:16:09,670 --> 00:16:12,960
kufuata hatua sawa kwamba
itatoa online nyaraka.

333
00:16:12,960 --> 00:16:16,360
Hivyo huna haja ya kuwa na wasiwasi kuhusu
absorbing kila hatua kidogo ya kiufundi

334
00:16:16,360 --> 00:16:17,730
kwamba mimi kufanya hapa leo.

335
00:16:17,730 --> 00:16:19,222
>> Lakini utasikia kupata screen kama hii.

336
00:16:19,222 --> 00:16:20,430
Mimi kutokea kwa kuwa katika hali ya usiku.

337
00:16:20,430 --> 00:16:22,944
Na unaweza kuangaza kila kitu
up kwa mlemavu mode usiku.

338
00:16:22,944 --> 00:16:24,860
Na mwishoni mwa
siku, wewe ni kwenda kuona

339
00:16:24,860 --> 00:16:30,090
hawa watatu kuu areas-- faili
kisakuzi upande wa kushoto, tabo code juu juu,

340
00:16:30,090 --> 00:16:32,430
na terminal dirisha chini.

341
00:16:32,430 --> 00:16:34,890
>> Hebu kwenda mbele na
kuandika mpango wangu wa kwanza.

342
00:16:34,890 --> 00:16:42,300
Mimi nina kwenda preemptively kwenda Picha,
Ila, na kuokoa faili yangu kama hello.c.

343
00:16:42,300 --> 00:16:46,850
Hakika, kwa mkataba huo, yoyote sisi mpango
kuandika kwamba imeandikwa katika lugha C

344
00:16:46,850 --> 00:16:49,739
lazima jina lake jambo
dot c, kwa mkataba.

345
00:16:49,739 --> 00:16:53,030
Hivyo nina kwenda kwa jina hilo hello.c, kwa sababu
Mimi nataka tu kusema hello dunia.

346
00:16:53,030 --> 00:16:54,820
Sasa mimi nina kwenda kuvuta
nje na bonyeza Hifadhi.

347
00:16:54,820 --> 00:16:58,180
Na wote mimi hapa sasa ni tab
katika ambayo siwezi kuanza kuandika code.

348
00:16:58,180 --> 00:16:59,490
>> Hii si kwenda kukusanya.

349
00:16:59,490 --> 00:17:00,300
Hii ina maana chochote.

350
00:17:00,300 --> 00:17:02,750
Na hivyo hata kama mimi waongofu
huu kwa zeros na ndio,

351
00:17:02,750 --> 00:17:05,390
CPU ni kwenda kuwa hakuna
Wazo nini kinaendelea karibu.

352
00:17:05,390 --> 00:17:14,170
Lakini kama mimi kuandika mistari ambayo hayana mechi
juu na C ya conventions-- C kuwa,

353
00:17:14,170 --> 00:17:20,150
tena, hii language-- na syntax kama
hii, printf hujambo world-- na nimekuwa

354
00:17:20,150 --> 00:17:22,210
wamezipata starehe na
kufanya hivyo baada ya muda.

355
00:17:22,210 --> 00:17:24,510
Hivyo sidhani mimi alifanya
yoyote typographical makosa.

356
00:17:24,510 --> 00:17:27,910
>> Lakini, invariably, kwanza kabisa
muda wa kufanya hii, wewe.

357
00:17:27,910 --> 00:17:31,090
Na kile Mimi kuhusu kufanya nguvu sana
vizuri kazi kwa ajili yenu mara ya kwanza.

358
00:17:31,090 --> 00:17:33,610
Na kwamba ni sawa kabisa,
kwa sababu sasa hivi wewe

359
00:17:33,610 --> 00:17:37,662
ili tu kuona mengi yote ya upya,
lakini baada ya muda mara moja kupata ukoo

360
00:17:37,662 --> 00:17:39,870
na mazingira haya, na
Lugha hii, na wengine,

361
00:17:39,870 --> 00:17:42,370
itabidi kuanza kuona mambo ambayo
ni aidha sahihi au sio sahihi.

362
00:17:42,370 --> 00:17:44,369
>> Na hii ni nini
wenzake mafundisho na bila shaka

363
00:17:44,369 --> 00:17:48,780
wasaidizi kupata nzuri katika baada ya muda, ni
spotting makosa au mende katika kanuni yako.

364
00:17:48,780 --> 00:17:52,110
Lakini mimi kudai kwamba kuna
hakuna mende katika kanuni hii.

365
00:17:52,110 --> 00:17:53,990
Hivyo mimi sasa wanataka kuendesha mpango huu.

366
00:17:53,990 --> 00:17:57,440
>> Sasa juu ya Mac yangu mwenyewe au PC, mimi niko katika
tabia ya icons kubonyeza mara mbili

367
00:17:57,440 --> 00:17:59,350
wakati nataka kukimbia baadhi ya mpango.

368
00:17:59,350 --> 00:18:01,080
Lakini si kwamba mfano hapa.

369
00:18:01,080 --> 00:18:04,570
Katika mazingira haya, ambayo ni CS50 IDE.

370
00:18:04,570 --> 00:18:07,192
Sisi ni kutumia uendeshaji
mfumo uitwao Linux.

371
00:18:07,192 --> 00:18:09,900
Linux ni kukumbusha ya mwingine
mfumo wa uendeshaji, kwa ujumla inayojulikana

372
00:18:09,900 --> 00:18:10,850
kama Unix.

373
00:18:10,850 --> 00:18:16,340
Na Linux ni hasa maalumu kwa ajili
kuwa amri Line Mazingira, CLI.

374
00:18:16,340 --> 00:18:20,070
Sasa, sisi ni kutumia maalum
ladha ya Linux aitwaye Ubuntu.

375
00:18:20,070 --> 00:18:22,770
Na Ubuntu ni tu
baadhi ya toleo la Linux.

376
00:18:22,770 --> 00:18:27,900
>> Lakini hizi Linux ya siku hizi kufanya kweli
kuja na interfaces user graphical.

377
00:18:27,900 --> 00:18:30,360
Na moja sisi kutokea kwa
kutumia hapa ni mtandao msingi.

378
00:18:30,360 --> 00:18:32,735
Hivyo hii inaweza kuangalia hata
tofauti kidogo kutoka kitu

379
00:18:32,735 --> 00:18:35,310
wewe mwenyewe anaweza kuwa
kuonekana au kukimbia katika siku za nyuma.

380
00:18:35,310 --> 00:18:37,910
>> Hivyo mimi nina kwenda mbele
sasa na kufanya yafuatayo.

381
00:18:37,910 --> 00:18:40,950
Nimekuwa kuokolewa faili hili kama hello.c.

382
00:18:40,950 --> 00:18:47,350
Mimi nina kwenda mbele na
aina clanghello.c Hivyo Clang

383
00:18:47,350 --> 00:18:49,850
kwa lugha C ni compiler.

384
00:18:49,850 --> 00:18:51,952
Ni kabla ya imewekwa katika CS50 IDE.

385
00:18:51,952 --> 00:18:54,910
Na unaweza kabisa kushusha na
kufunga hii juu ya Mac yako mwenyewe au PC.

386
00:18:54,910 --> 00:18:57,910
>> Lakini tena, bila kuwa yote ya
kabla ya Configuration aliyokutendea.

387
00:18:57,910 --> 00:19:00,940
Hivyo kwa sasa, mimi nina tu
kwenda kukimbia clanghello.c.

388
00:19:00,940 --> 00:19:03,240
Na sasa taarifa syntax hii
hapa hatimaye

389
00:19:03,240 --> 00:19:06,930
kutambua tu ina maana kwamba mimi niko katika
folder au directory aitwaye Workspace.

390
00:19:06,930 --> 00:19:11,030
Hii ishara ya dola ni mkataba
kwa maana, aina amri yako hapa.

391
00:19:11,030 --> 00:19:14,560
>> Ni kile kinachoitwa haraka, tu
kwa mkataba ni dola ishara.

392
00:19:14,560 --> 00:19:19,130
Na kama mimi kwenda mbele sasa na bonyeza
Kuingia, kitu inaonekana kuwa kilichotokea.

393
00:19:19,130 --> 00:19:20,930
Lakini hiyo ni kweli jambo zuri.

394
00:19:20,930 --> 00:19:23,650
chini ambayo hufanyika kwenye
screen yako, zaidi ya uwezekano

395
00:19:23,650 --> 00:19:26,710
kanuni yako ni kuwa sahihi,
angalau syntactically.

396
00:19:26,710 --> 00:19:29,120
>> Hivyo kama nataka kukimbia hii
mpango, nini mimi?

397
00:19:29,120 --> 00:19:33,770
Naam, zinageuka kuwa
jina default kwa mkataba

398
00:19:33,770 --> 00:19:38,854
kwa ajili ya programu wakati huna bayana
jina kwa ajili ya mpango wako ni a.out.

399
00:19:38,854 --> 00:19:41,270
Na syntax hii pia, utasikia
kupata ukoo na kabla ya muda mrefu.

400
00:19:41,270 --> 00:19:47,500
>> Dot kufyeka ina maana tu, hey, CS50
IDE, kukimbia mpango ujulikanao a.out

401
00:19:47,500 --> 00:19:49,400
hiyo ni ndani ya saraka yangu ya sasa.

402
00:19:49,400 --> 00:19:51,520
dot Hiyo ina maana saraka ya sasa.

403
00:19:51,520 --> 00:19:55,040
Na tutaweza kuona nini wengine Utaratibu kama
ya wahusika ina maana kabla ya muda mrefu.

404
00:19:55,040 --> 00:19:58,430
>> Hivyo hapa sisi kwenda, Ingieni, hujambo dunia.

405
00:19:58,430 --> 00:20:00,080
Na wewe utakuwa taarifa, kwamba ni nini kilichotokea?

406
00:20:00,080 --> 00:20:01,580
Si tu kwamba ni magazeti hujambo dunia.

407
00:20:01,580 --> 00:20:05,990
Pia wakiongozwa
mshale wa mstari wa pili.

408
00:20:05,990 --> 00:20:07,160
>> Na kwa nini ni kwamba?

409
00:20:07,160 --> 00:20:12,400
Ilikuwa kificho kwamba sisi aliandika kabla ya kile
kwamba kuhakikisha kwamba mshale ingekuwa

410
00:20:12,400 --> 00:20:14,882
kwenda kwenye mstari baada ya hapo?

411
00:20:14,882 --> 00:20:16,840
Mapenzi kitu kuhusu
kompyuta ni ni kwenda tu

412
00:20:16,840 --> 00:20:18,570
kufanya literally nini kuwaambia ni kufanya.

413
00:20:18,570 --> 00:20:26,050
>> Hivyo kama wewe kuwaambia ni printf hello,
comma, nafasi, dunia, karibu quote,

414
00:20:26,050 --> 00:20:29,090
ni literally tu kwenda
magazeti wahusika hao.

415
00:20:29,090 --> 00:20:31,980
Lakini nilikuwa na tabia hii maalum
mwishoni, kukumbuka, backslash n.

416
00:20:31,980 --> 00:20:34,230
Na kwamba ni nini kuhakikisha
kwamba tabia alikwenda

417
00:20:34,230 --> 00:20:36,570
mstari wa pili ya screen.

418
00:20:36,570 --> 00:20:38,097
>> Kwa kweli, napenda kwenda na kufanya hivyo.

419
00:20:38,097 --> 00:20:39,430
Hebu kwenda mbele na kufuta hii.

420
00:20:39,430 --> 00:20:41,180
Sasa, taarifa kwamba
juu ya screen yangu kuna

421
00:20:41,180 --> 00:20:42,890
kidogo nyekundu mwanga katika
tab kuonyesha,

422
00:20:42,890 --> 00:20:45,047
hey, umefanya si kuokolewa faili yako.

423
00:20:45,047 --> 00:20:47,880
Hivyo mimi nina kwenda mbele na udhibiti
S au amri S, kuokoa faili.

424
00:20:47,880 --> 00:20:51,130
Sasa ni goes-- alikwenda kwa ajili ya kijani moment--.

425
00:20:51,130 --> 00:20:53,760
Na sasa ni nyuma
tu kuwa icon karibu.

426
00:20:53,760 --> 00:21:01,860
>> Kama mimi sasa kukimbia clanghello.c tena,
Kuingia, dot kufyeka, a.out, Ingieni,

427
00:21:01,860 --> 00:21:04,110
utaona kwamba bado kazi.

428
00:21:04,110 --> 00:21:06,020
Lakini ni arguably buggy kidogo.

429
00:21:06,020 --> 00:21:08,714
Hivi sasa, workspace yangu prompt--,
na kisha kuwa ishara ya dola,

430
00:21:08,714 --> 00:21:10,880
na kisha prompt-- yangu halisi
yote ni juu ya mstari huo.

431
00:21:10,880 --> 00:21:14,540
Hivyo bila ya shaka hii mdudu aesthetic,
hata kama ni kweli mantiki mdudu.

432
00:21:14,540 --> 00:21:16,250
>> Hivyo nina kwenda kuondoa nini mimi tu alifanya.

433
00:21:16,250 --> 00:21:18,560
Mimi nina kwenda rerun a.out.

434
00:21:18,560 --> 00:21:22,710
Ilani nimekuwa aliongeza
newline tabia nyuma.

435
00:21:22,710 --> 00:21:24,280
Nimekuwa kuokolewa file.

436
00:21:24,280 --> 00:21:31,630
>> Hivyo nina kwenda kwa rerun a.out, and--
Dammit, mdudu, mdudu maana makosa.

437
00:21:31,630 --> 00:21:35,020
Hivyo mdudu ni kwamba hata kama
Mimi aliongeza backslash n huko,

438
00:21:35,020 --> 00:21:41,180
re-kuokolewa, re-mbio mpango,
tabia ilikuwa sawa.

439
00:21:41,180 --> 00:21:42,640
Kwa nini ingekuwa kwamba kuwa?

440
00:21:42,640 --> 00:21:43,910
>> Mimi kukosa hatua, haki?

441
00:21:43,910 --> 00:21:47,620
Hiyo hatua muhimu mapema ni kwamba una
to-- wakati mabadiliko ya chanzo kanuni yako,

442
00:21:47,620 --> 00:21:49,610
ni zamu nje pia kukimbia
hivyo kwa njia ya compiler

443
00:21:49,610 --> 00:21:51,102
tena ili kupata mpya mashine kanuni.

444
00:21:51,102 --> 00:21:52,810
Na mashine kanuni,
zeros na ndio,

445
00:21:52,810 --> 00:21:56,260
ni kwenda kuwa karibu sawa, lakini
si kikamilifu hivyo, kwa sababu tunahitaji,

446
00:21:56,260 --> 00:21:57,510
bila shaka, kwamba mstari mpya.

447
00:21:57,510 --> 00:22:02,640
>> Hivyo kurekebisha hili, mimi nina kwenda haja
kwa rerun clanghello.c, kuingia, dot

448
00:22:02,640 --> 00:22:03,800
kufyeka, a.out.

449
00:22:03,800 --> 00:22:08,402
Na sasa, hello dunia ni nyuma
ambapo mimi kutarajia kuwa ni.

450
00:22:08,402 --> 00:22:09,610
Hivyo hii yote ni mzuri na mwema.

451
00:22:09,610 --> 00:22:13,150
Lakini a.out ni jina pretty kijinga kwa
mpango, ingawa hutokea kwa kuwa,

452
00:22:13,150 --> 00:22:16,530
kwa sababu za kihistoria,
default-- maana kusanyiko mazao.

453
00:22:16,530 --> 00:22:20,780
>> Lakini basi mimi kwenda mbele hapa
na kufanya hivyo kwa njia tofauti.

454
00:22:20,780 --> 00:22:24,760
Nataka yangu mpango hujambo dunia
kwa kweli kuitwa hello.

455
00:22:24,760 --> 00:22:28,320
Hivyo kama ilivyokuwa icon kwenye yangu
desktop, bila kuwa na a.out.

456
00:22:28,320 --> 00:22:29,730
Ingekuwa kuitwa hello.

457
00:22:29,730 --> 00:22:33,660
>> Hivyo kufanya hili, ni zamu nje
kwamba Clang, kama mipango mingi,

458
00:22:33,660 --> 00:22:37,980
inasaidia hoja mstari amri,
au bendera, au swichi,

459
00:22:37,980 --> 00:22:39,600
ambayo tu kuchangia tabia yake.

460
00:22:39,600 --> 00:22:45,160
Hasa, Clang inasaidia dash o
bendera, ambayo kisha inachukua neno la pili.

461
00:22:45,160 --> 00:22:48,190
Katika kesi hiyo, mimi itabidi kiholela,
lakini sababu, simu yake hello.

462
00:22:48,190 --> 00:22:50,710
Lakini mimi naweza kuiita kitu chochote
Nataka, isipokuwa a.out, ambayo

463
00:22:50,710 --> 00:22:52,390
Itakuwa badala badala ya uhakika.

464
00:22:52,390 --> 00:22:55,640
>> Na kisha tu kutaja jina
ya faili mimi wanataka kukusanya.

465
00:22:55,640 --> 00:22:59,190
Hivyo sasa ingawa mwanzoni
amri mimi bado kuwa Clang,

466
00:22:59,190 --> 00:23:01,410
mwishoni mwa amri
Mimi bado wana jina la faili,

467
00:23:01,410 --> 00:23:05,520
Mimi sasa kuwa na hizi mstari amri
hoja, hizi bendera kwamba ni kusema,

468
00:23:05,520 --> 00:23:11,180
oh, kwa njia, pato-o, faili
aitwaye hello, si default a.out.

469
00:23:11,180 --> 00:23:13,810
>> Hivyo kama mimi hit Enter sasa, hakuna kitu
inaonekana kuwa kilichotokea.

470
00:23:13,810 --> 00:23:17,900
Na, hata hivyo, sasa siwezi kufanya dot kufyeka hello.

471
00:23:17,900 --> 00:23:19,089
Hivyo ni mpango huo.

472
00:23:19,089 --> 00:23:21,380
zeros na ndio ni
kufanana mwisho wa siku.

473
00:23:21,380 --> 00:23:24,210
>> Lakini wao uko katika wawili
tofauti files-- a.out,

474
00:23:24,210 --> 00:23:26,490
ambayo ni toleo la kwanza
na tu upumbavu jina lake,

475
00:23:26,490 --> 00:23:30,250
na sasa hello, ambayo ni mengi
zaidi ya kulazimisha jina kwa ajili ya mpango.

476
00:23:30,250 --> 00:23:33,195
Lakini, kwa uaminifu, mimi kamwe
kwenda kukumbuka hii tena,

477
00:23:33,195 --> 00:23:34,070
na tena, na tena.

478
00:23:34,070 --> 00:23:36,411
Na, kwa kweli, kama sisi kuandika
mipango ngumu zaidi,

479
00:23:36,411 --> 00:23:38,160
amri uko
kwenda na kuandika

480
00:23:38,160 --> 00:23:40,920
ni kwenda kupata hata
ngumu zaidi bado.

481
00:23:40,920 --> 00:23:41,940
>> Na hivyo si kuwa na wasiwasi.

482
00:23:41,940 --> 00:23:46,220
Ni zinageuka kuwa binadamu kabla
sisi wamebaini wao pia

483
00:23:46,220 --> 00:23:47,530
alikuwa na haya tatizo exact.

484
00:23:47,530 --> 00:23:50,900
Wao pia hakuwa na kufurahia kuwa na
aina haki muda mrefu, arcane amri,

485
00:23:50,900 --> 00:23:52,200
achilia kukumbuka.

486
00:23:52,200 --> 00:23:56,070
Na hivyo binadamu mbele yetu kuwa alifanya
programu nyingine ambayo iwe rahisi

487
00:23:56,070 --> 00:23:57,670
kukusanya programu yako.

488
00:23:57,670 --> 00:24:01,609
>> Na, kwa hakika, mmoja kama
mpango inaitwa Tengeneza.

489
00:24:01,609 --> 00:24:03,150
Hivyo mimi nina kwenda mbele na kufanya hili.

490
00:24:03,150 --> 00:24:05,691
Mimi nina kwenda tengua kila kitu mimi
tu alifanya katika njia zifuatazo.

491
00:24:05,691 --> 00:24:07,690
Hebu aina LS.

492
00:24:07,690 --> 00:24:10,980
Na wewe utakuwa taarifa tatu things--
a.out, na nyota, hello

493
00:24:10,980 --> 00:24:12,810
na nyota, na hello.c.

494
00:24:12,810 --> 00:24:14,730
Hopefully, hii lazima
kuwa ni kidogo Intuitive,

495
00:24:14,730 --> 00:24:18,220
kadiri mapema kulikuwa na
kitu katika workspace hii.

496
00:24:18,220 --> 00:24:21,240
Kulikuwa na kitu kuwa nilikuwa
umba mpaka tulianza darasani.

497
00:24:21,240 --> 00:24:22,840
>> Na mimi kuundwa hello.c.

498
00:24:22,840 --> 00:24:24,544
Mimi kisha ulioandaliwa yake, na kuitwa ni a.out.

499
00:24:24,544 --> 00:24:27,460
Na kisha mimi ulioandaliwa hivyo tena kidogo
tofauti na kuitwa ni hello.

500
00:24:27,460 --> 00:24:32,830
Hivyo nina mafaili tatu katika orodha hii,
katika folda hii inaitwa Workspace.

501
00:24:32,830 --> 00:24:35,005
Sasa, naona kuwa vilevile
kama mimi kuvuta nje kweli.

502
00:24:35,005 --> 00:24:37,530
>> Kama mimi kuvuta nje hapa na
tuangalie mkono kwamba juu kulia

503
00:24:37,530 --> 00:24:39,940
kona, kama alivyoahidi kushoto
upande mkono wa screen yako

504
00:24:39,940 --> 00:24:42,990
ni daima kwenda kwa kuonyesha
nini katika akaunti yako, nini

505
00:24:42,990 --> 00:24:44,790
ndani ya CS50 IDE.

506
00:24:44,790 --> 00:24:46,680
Na kuna files tatu huko.

507
00:24:46,680 --> 00:24:49,070
>> Hivyo nataka kujikwamua a.out na hello.

508
00:24:49,070 --> 00:24:51,275
Na kama waweza
kufikiria intuitively, wewe

509
00:24:51,275 --> 00:24:53,400
inaweza kutatua ya kudhibiti click
au haki click juu ya hili.

510
00:24:53,400 --> 00:24:54,590
Na hii orodha kidogo pops up.

511
00:24:54,590 --> 00:24:57,170
Unaweza kushusha faili, kukimbia
hivyo, hakikisho hilo, mahitaji, kubadili jina,

512
00:24:57,170 --> 00:24:57,700
au kile si.

513
00:24:57,700 --> 00:25:00,260
>> Na mimi naweza kufuta tu,
na ingekuwa kwenda mbali.

514
00:25:00,260 --> 00:25:05,260
Lakini hebu kufanya mambo kwa amri
line kwa sasa, ili kupata starehe

515
00:25:05,260 --> 00:25:07,010
na hii, na kufanya yafuatayo.

516
00:25:07,010 --> 00:25:12,345
Mimi nina kwenda mbele na kuondoa
a.out kwa kuandika literally rma.out.

517
00:25:12,345 --> 00:25:14,890
Zinageuka, amri kwa
kuondoa au kufuta kitu,

518
00:25:14,890 --> 00:25:16,280
si kuondoa au kufuta.

519
00:25:16,280 --> 00:25:21,260
>> Ni ufupi zaidi RM, tu kuokoa
baadhi keystrokes, na hit Enter.

520
00:25:21,260 --> 00:25:24,707
Sasa tunakwenda kuwa fulani
isiyoeleweka kirahisi kuondoa mara kwa mara file a.out.

521
00:25:24,707 --> 00:25:27,040
Mimi si kweli kujua nini
kawaida file itakuwa bado.

522
00:25:27,040 --> 00:25:28,660
Lakini mimi wanataka kuondoa hiyo.

523
00:25:28,660 --> 00:25:30,150
>> Hivyo mimi nina kwenda aina y kwa ndiyo.

524
00:25:30,150 --> 00:25:31,940
Au mimi naweza aina yake nje, na hit Enter.

525
00:25:31,940 --> 00:25:33,440
Na, tena, kitu inaonekana kutokea.

526
00:25:33,440 --> 00:25:35,840
Lakini hiyo ni, kwa ujumla, ni jambo jema.

527
00:25:35,840 --> 00:25:40,490
>> Kama mimi aina LS wakati huu,
nifanye kuona?

528
00:25:40,490 --> 00:25:44,930
Hopefully, hello tu na hello.c.

529
00:25:44,930 --> 00:25:47,286
Sasa, kama kando, utasikia
taarifa nyota hii, kinyota,

530
00:25:47,286 --> 00:25:48,660
hiyo ni mwishoni mwa mipango yangu.

531
00:25:48,660 --> 00:25:50,201
Na wao ni pia kuonyesha juu katika kijani.

532
00:25:50,201 --> 00:25:53,970
Hiyo ni njia tu CS50 IDE ya
ya cluing wewe katika ukweli

533
00:25:53,970 --> 00:25:55,280
kwamba si kwamba chanzo kanuni.

534
00:25:55,280 --> 00:25:58,880
Hiyo ni executable, runnable
mpango kwamba unaweza kweli kuendesha

535
00:25:58,880 --> 00:26:01,020
kwa kufanya dot kufyeka, na kisha ni jina.

536
00:26:01,020 --> 00:26:05,860
>> Sasa, basi mimi kwenda mbele na kuondoa
huu, rm hello, Enter, kuondoa mara kwa mara

537
00:26:05,860 --> 00:26:08,010
faili hello, ndiyo.

538
00:26:08,010 --> 00:26:11,180
Na sasa kama mimi aina LS,
tuko nyuma kwa hello.c.

539
00:26:11,180 --> 00:26:13,917
Jaribu kufuta yako
halisi chanzo kanuni.

540
00:26:13,917 --> 00:26:16,250
Hata ingawa kuna makala
kujengwa katika CS50 IDE ambapo

541
00:26:16,250 --> 00:26:19,870
unaweza kwenda kupitia historia yako marekebisho
na rewind katika wakati kama ajali

542
00:26:19,870 --> 00:26:23,660
kufuta kitu, kufanya kukumbuka
kama kwa papo hizi ndiyo au hapana,

543
00:26:23,660 --> 00:26:25,381
ya nini hasa unataka kufanya.

544
00:26:25,381 --> 00:26:27,380
Na nikienda hadi juu
mkono wa kushoto kona hapa,

545
00:26:27,380 --> 00:26:30,696
wote kwamba bado ni hello.c.

546
00:26:30,696 --> 00:26:32,570
Hivyo kuna mashada ya
amri nyingine kwamba wewe

547
00:26:32,570 --> 00:26:37,550
unaweza nitafanya katika ulimwengu wa Linux,
moja ambayo ni, tena, Tengeneza.

548
00:26:37,550 --> 00:26:40,180
Na tunakwenda Tengeneza
mpango wangu sasa kama ifuatavyo.

549
00:26:40,180 --> 00:26:43,270
>> Badala ya kufanya Clang,
badala ya kufanya Clang-o,

550
00:26:43,270 --> 00:26:45,860
Mimi nina kwenda tu
literally aina, kufanya hello.

551
00:26:45,860 --> 00:26:49,630
Na sasa taarifa, mimi niko
si kuandika kufanya hello.c.

552
00:26:49,630 --> 00:26:50,910
Mimi kuandika kufanya hello.

553
00:26:50,910 --> 00:26:54,840
>> Na mpango huu Matokeo kwamba
kuja na CS50 IDE, na zaidi

554
00:26:54,840 --> 00:26:57,090
ujumla na Linux,
ni mpango kwamba ni

555
00:26:57,090 --> 00:26:59,120
kwenda kufanya programu inayoitwa Hello.

556
00:26:59,120 --> 00:27:03,680
Na itakuja kwa kudhani, kwa mkataba,
kwamba kama mpango huu unaweza kufanywa,

557
00:27:03,680 --> 00:27:09,030
itakuja kuwa alifanya kutoka chanzo
kificho faili kuishia katika dot c, hello.c.

558
00:27:09,030 --> 00:27:12,210
>> Hivyo kama mimi hit Enter sasa, taarifa kwamba
amri kwamba anapata kunyongwa

559
00:27:12,210 --> 00:27:14,340
ni kweli hata tena
kabla kuliko kabla.

560
00:27:14,340 --> 00:27:16,670
Na kwamba kwa sababu tumekuwa
preconfigured CS50 IDE kuwa na

561
00:27:16,670 --> 00:27:19,878
baadhi ya vipengele ziada kujengwa katika kwamba
hatuna haja bado tu, lakini hapo.

562
00:27:19,878 --> 00:27:23,470
Lakini jambo muhimu kutambua
ni sasa nina mpango Hello.

563
00:27:23,470 --> 00:27:27,080
>> Kama mimi aina LS tena, mimi
kuwa na mpango hello.

564
00:27:27,080 --> 00:27:32,070
Na siwezi kuendesha kwa
dot kufyeka a.out, hapana,

565
00:27:32,070 --> 00:27:35,590
kwa sababu hatua nzima ya hii
zoezi mara dot kufyeka hello.

566
00:27:35,590 --> 00:27:38,089
Na sasa nina wangu mpango hujambo dunia.

567
00:27:38,089 --> 00:27:39,880
Hivyo kusonga mbele,
tuko karibu kila mara tu

568
00:27:39,880 --> 00:27:42,088
kwenda kukusanya mipango yetu
kutumia amri Tengeneza.

569
00:27:42,088 --> 00:27:45,300
Na kisha tunakwenda kukimbia nao na
dot kufyeka, na jina wa programu hiyo.

570
00:27:45,300 --> 00:27:49,610
Lakini kutambua nini Kufanya anafanya kwa
wewe, ni yenyewe si compiler.

571
00:27:49,610 --> 00:27:53,310
Ni tu mpango urahisi
kwamba anajua jinsi ya kusababisha compiler

572
00:27:53,310 --> 00:27:56,470
kuendesha hivyo kuwa wewe mwenyewe unaweza kuitumia.

573
00:27:56,470 --> 00:28:00,220
>> Nini amri nyingine zipo katika
Linux, na kwa upande CS50 IDE?

574
00:28:00,220 --> 00:28:03,107
Tutaweza hivi karibuni kuona kwamba kuna
CD amri, Change City.

575
00:28:03,107 --> 00:28:05,190
Hii utapata ndani ya
yako amri Mpya interface

576
00:28:05,190 --> 00:28:07,610
kusonga mbele, na nyuma,
na kufungua folders tofauti

577
00:28:07,610 --> 00:28:08,860
bila kutumia mouse yako.

578
00:28:08,860 --> 00:28:12,470
>> LS tuliona, ambayo inasimamia kwa orodha
files katika saraka ya sasa.

579
00:28:12,470 --> 00:28:14,650
Kufanya Dir, unaweza
pengine kuanza kwa kudai

580
00:28:14,650 --> 00:28:18,150
nini haya yana maana now-- kufanya directory,
kama unataka kujenga folder.

581
00:28:18,150 --> 00:28:21,270
RM kwa kuondoa, RM Dir kwa
kuondoa saraka na hayo,

582
00:28:21,270 --> 00:28:24,160
tena, ni mstari amri
EQUIVALENTS ya nini

583
00:28:24,160 --> 00:28:26,945
anaweza kufanya katika CS50 IDE na panya yako.

584
00:28:26,945 --> 00:28:28,820
Lakini utasikia hivi karibuni kupata
kwamba wakati mwingine ni tu

585
00:28:28,820 --> 00:28:30,610
mengi kwa kasi ya kufanya
mambo kwa keyboard,

586
00:28:30,610 --> 00:28:33,690
na hatimaye mengi na nguvu zaidi.

587
00:28:33,690 --> 00:28:36,440
>> Lakini ni vigumu wanasema kuwa
chochote tumekuwa kufanya hivyo mbali

588
00:28:36,440 --> 00:28:39,990
ni kwamba wote wenye nguvu, wakati wote
tumekuwa akisema ni, hujambo dunia.

589
00:28:39,990 --> 00:28:43,740
Na, kwa kweli, mimi hardcoded
Maneno hujambo dunia katika mpango wangu.

590
00:28:43,740 --> 00:28:45,530
Hakuna mabadiliko bado.

591
00:28:45,530 --> 00:28:49,320
Scratch ilikuwa utaratibu wa ukubwa
zaidi ya kuvutia wiki iliyopita.

592
00:28:49,320 --> 00:28:51,220
>> Na hivyo hebu kupata huko.

593
00:28:51,220 --> 00:28:55,310
Hebu kuchukua hatua kuelekea kuwa na
njia ya baadhi ya kazi hizi.

594
00:28:55,310 --> 00:28:59,470
Hivyo si tu haina C kuja na printf,
na mashada ya kazi nyingine

595
00:28:59,470 --> 00:29:01,850
baadhi ya ambayo tutaweza kuona
baada ya muda, haina

596
00:29:01,850 --> 00:29:05,760
kufanya hivyo wote kuwa rahisi haki nje
ya lango katika kupata user pembejeo.

597
00:29:05,760 --> 00:29:08,140
>> Kwa kweli, moja ya udhaifu
ya lugha kama C,

598
00:29:08,140 --> 00:29:10,140
na hata Java na bado
wengine, ni kwamba hana

599
00:29:10,140 --> 00:29:15,860
kufanya hivyo ni rahisi kupata tu vitu kama
integers kutoka kwa watumiaji, au masharti, maneno,

600
00:29:15,860 --> 00:29:19,970
na misemo, basi mambo peke yake kama
yaliyo hatua maadili, au idadi halisi

601
00:29:19,970 --> 00:29:23,240
ikiwa na pointi decimal, na kwa kweli
idadi ya muda mrefu, kama tutaweza hivi karibuni kuona.

602
00:29:23,240 --> 00:29:27,000
Hivyo hii orodha ya kazi hapa, hizi
ni kama vipande nyingine Scratch puzzle

603
00:29:27,000 --> 00:29:31,090
kwamba tuna kabla ya imewekwa katika CS50
IDE kwamba tutaweza kutumia kwa muda wa wiki chache

604
00:29:31,090 --> 00:29:34,010
kama magurudumu mafunzo ya kila aina, na
hatimaye kuchukua mbali, na kuangalia

605
00:29:34,010 --> 00:29:37,210
chini ya kofia, pengine, katika
jinsi mambo haya yanatekelezwa.

606
00:29:37,210 --> 00:29:40,460
>> Lakini kwa kufanya hivyo, hebu
kweli kuandika mpango.

607
00:29:40,460 --> 00:29:41,770
Hebu kwenda mbele sasa.

608
00:29:41,770 --> 00:29:44,750
Na mimi nina kwenda kujenga mpya
faili kwa kubonyeza hii pamoja kidogo,

609
00:29:44,750 --> 00:29:45,970
na kubonyeza New faili.

610
00:29:45,970 --> 00:29:49,250
>> Mimi nina kwenda kuokoa hii ijayo
moja kama, hebu sema, string.c,

611
00:29:49,250 --> 00:29:50,750
kwa sababu nataka kucheza na masharti.

612
00:29:50,750 --> 00:29:53,990
Na kamba katika C ni tu
mlolongo wa wahusika.

613
00:29:53,990 --> 00:29:56,090
Hivyo sasa hebu kwenda mbele
na kufanya yafuatayo.

614
00:29:56,090 --> 00:30:01,204
>> Pamoja na kiwango IO.h-- na
ni zamu nje kiwango IO,

615
00:30:01,204 --> 00:30:03,360
IO tu ina maana pembejeo na mazao.

616
00:30:03,360 --> 00:30:05,920
Hivyo zinageuka kuwa
mstari huu hapa ni nini

617
00:30:05,920 --> 00:30:08,140
ni jirani yetu kwa kutumia printf.

618
00:30:08,140 --> 00:30:10,410
Printf, bila shaka, inazalisha pato.

619
00:30:10,410 --> 00:30:15,000
Hivyo ili kutumia printf, ni zamu
nje unaweza kuwa na hii mstari wa kanuni

620
00:30:15,000 --> 00:30:16,040
katika juu ya faili yako.

621
00:30:16,040 --> 00:30:18,456
>> Na tutaweza kuja nyuma kwa nini
lilikuwa na maana kuwa kabla ya muda mrefu.

622
00:30:18,456 --> 00:30:20,400
Ni zinageuka kuwa katika
mpango wowote C mimi kuandika,

623
00:30:20,400 --> 00:30:23,640
Mimi nimepata kuanza kwa
kificho kwamba inaonekana kama hii.

624
00:30:23,640 --> 00:30:26,860
Na wewe utakuwa taarifa CS50 IDE, na
maendeleo nyingine jumuishi

625
00:30:26,860 --> 00:30:30,050
mazingira kama hayo,
ni kwenda kujaribu kama bora

626
00:30:30,050 --> 00:30:31,780
wanaweza kumaliza mawazo yako.

627
00:30:31,780 --> 00:30:35,930
Kwa kweli, wakati iliyopita kama mimi tengua
nini mimi tu alifanya, mimi hit Enter.

628
00:30:35,930 --> 00:30:39,160
>> Mimi kisha kugonga wazi curly
brace, kugonga kuingia tena.

629
00:30:39,160 --> 00:30:40,430
Na ni kumaliza mawazo yangu.

630
00:30:40,430 --> 00:30:45,140
Ni alinipa mstari wa mwezi, indented si chini
kwa sababu nzuri Stylistic tutaweza kuona.

631
00:30:45,140 --> 00:30:48,559
Na kisha ni moja kwa moja alinipa
kwamba brace curly kumaliza mawazo yangu.

632
00:30:48,559 --> 00:30:50,600
Sasa, haina daima
nadhani nini unataka kufanya.

633
00:30:50,600 --> 00:30:53,620
Lakini kwa sehemu kubwa, ni gani
kuokoa baadhi keystrokes.

634
00:30:53,620 --> 00:30:59,560
Hivyo wakati iliyopita, sisi mbio program-- hii
hello, dunia, na kisha ulioandaliwa yake,

635
00:30:59,560 --> 00:31:00,460
na kisha akakimbia yake.

636
00:31:00,460 --> 00:31:01,867
Lakini hakuna mabadiliko hapa.

637
00:31:01,867 --> 00:31:03,700
Nini kama sisi alitaka
kufanya kitu tofauti?

638
00:31:03,700 --> 00:31:07,630
Naam, ni nini kama nilitaka kweli
kupata kamba kutoka kwa mtumiaji?

639
00:31:07,630 --> 00:31:11,250
Mimi naenda kutumia puzzle kipande
aitwaye hasa that-- kupata kamba.

640
00:31:11,250 --> 00:31:15,860
>> Zamu nje katika C kwamba wakati wewe hawataki
kutoa pembejeo kwa puzzle kipande,

641
00:31:15,860 --> 00:31:19,360
au vizuri zaidi kwa kazi,
literally tu kufanya mabano wazi,

642
00:31:19,360 --> 00:31:20,430
karibu mabano.

643
00:31:20,430 --> 00:31:25,540
Hivyo ni kana kwamba kuna
hakuna sanduku nyeupe ya aina ndani.

644
00:31:25,540 --> 00:31:27,720
kusema block kabla
alikuwa nyeupe kidogo sanduku.

645
00:31:27,720 --> 00:31:29,660
Hatuna kwamba sanduku nyeupe sasa.

646
00:31:29,660 --> 00:31:33,310
>> Lakini wakati mimi wito kupata kamba, I
unataka kuweka matokeo mahali fulani.

647
00:31:33,310 --> 00:31:37,680
Hivyo dhana ya kawaida sana katika C ni
piga kazi, kama kupata kamba hapa,

648
00:31:37,680 --> 00:31:41,070
na kisha kuhifadhi kurudi thamani yake.

649
00:31:41,070 --> 00:31:44,450
Ni matokeo ya yake
juhudi katika kitu fulani.

650
00:31:44,450 --> 00:31:47,630
>> Na ni nini
kujenga katika programu,

651
00:31:47,630 --> 00:31:53,450
iwe katika Scratch au sasa C, kwamba sisi
unaweza kutumia ili kweli kuhifadhi kitu?

652
00:31:53,450 --> 00:31:55,990
Kuitwa ni kutofautiana, haki?

653
00:31:55,990 --> 00:32:00,320
Na katika Scratch, sisi si kweli
huduma ya kile kinachoendelea katika vigezo.

654
00:32:00,320 --> 00:32:02,170
>> Lakini katika kesi hii, sisi kwa kweli kufanya.

655
00:32:02,170 --> 00:32:03,719
Mimi nina kwenda kusema kamba.

656
00:32:03,719 --> 00:32:05,510
Na kisha mimi naweza kuita
hii kitu chochote nataka.

657
00:32:05,510 --> 00:32:08,340
Mimi nina kwenda kuiita
jina, anapata kupata kamba.

658
00:32:08,340 --> 00:32:10,250
>> Na sasa hata kama wewe
mpya kidogo kwa hii,

659
00:32:10,250 --> 00:32:11,984
taarifa kwamba mimi nina anakosa baadhi ya kina.

660
00:32:11,984 --> 00:32:13,150
Mimi nina kusahau nusu koloni.

661
00:32:13,150 --> 00:32:14,400
Mimi haja ya kumaliza wazo hili.

662
00:32:14,400 --> 00:32:17,480
Hivyo nina kwenda kwa hoja ya mshale wangu,
na kugonga nusu koloni huko.

663
00:32:17,480 --> 00:32:19,130
Na tuna nini mimi tu kosa gani?

664
00:32:19,130 --> 00:32:21,440
Katika mstari wa kanuni,
namba 5 kwa wakati huu,

665
00:32:21,440 --> 00:32:23,799
Mimi nina wito kupata kamba na pembejeo hakuna.

666
00:32:23,799 --> 00:32:26,090
Hivyo hakuna nyeupe kidogo
sanduku kama Save kuzuia ina.

667
00:32:26,090 --> 00:32:28,590
>> Mimi tu kusema, hey,
kompyuta, kupata nami kamba.

668
00:32:28,590 --> 00:32:31,390
ishara sawa si kweli
ishara sawa, per se.

669
00:32:31,390 --> 00:32:33,790
Ni zoezi
operator, ambayo ina maana,

670
00:32:33,790 --> 00:32:37,860
hey, kompyuta, hoja thamani
kutoka kulia juu ya mkono wa kushoto.

671
00:32:37,860 --> 00:32:40,480
Na katika upande wa kushoto, nina zifuatazo.

672
00:32:40,480 --> 00:32:43,580
>> Hey, kompyuta, nipe kamba
mlolongo wa wahusika.

673
00:32:43,580 --> 00:32:45,637
Na wito kwamba Jina kamba.

674
00:32:45,637 --> 00:32:47,220
Na mimi si hata kuwa na kuiita Jina.

675
00:32:47,220 --> 00:32:49,970
>> Mimi naweza kuiita, conventionally,
kitu kama S,

676
00:32:49,970 --> 00:32:52,900
kiasi kama sisi kutumika i kwa
kuwaita kutofautiana i.

677
00:32:52,900 --> 00:32:54,829
Lakini sasa mimi haja ya kufanya kitu kwa hayo.

678
00:32:54,829 --> 00:32:57,370
Itakuwa pretty kijinga
kujaribu kuandaa kanuni hii, kukimbia

679
00:32:57,370 --> 00:32:59,410
huu mpango, ingawa
Mimi nina kupata kamba,

680
00:32:59,410 --> 00:33:01,580
kwa sababu ni bado tu
kwenda kusema hujambo dunia.

681
00:33:01,580 --> 00:33:06,140
>> Lakini nini kama mimi wanataka kubadili hali hii.

682
00:33:06,140 --> 00:33:07,940
Kwa nini si mimi kufanya hili?

683
00:33:07,940 --> 00:33:11,632
Asilimia s, comma s.

684
00:33:11,632 --> 00:33:13,090
Na hii ni kidogo cryptic bado.

685
00:33:13,090 --> 00:33:15,560
>> Hivyo basi mimi kufanya vigezo yangu wazi zaidi.

686
00:33:15,560 --> 00:33:17,510
Napenda kutaja Jina huu kutofautiana.

687
00:33:17,510 --> 00:33:20,230
Na hebu angalia kama hatuwezi tease
mbali nini kinatokea hapa.

688
00:33:20,230 --> 00:33:22,770
>> Hivyo kwenye mstari tano, mimi nina kupata kamba.

689
00:33:22,770 --> 00:33:25,620
Na mimi nina kuhifadhi kwamba kamba,
chochote mtumiaji typed katika

690
00:33:25,620 --> 00:33:28,430
katika keyboard yake,
katika variable kuitwa Jina.

691
00:33:28,430 --> 00:33:30,590
Na zinageuka kuwa
printf hana tu

692
00:33:30,590 --> 00:33:34,220
kuchukua moja hoja katika mara mbili
quotes, pembejeo moja katika quotes mbili.

693
00:33:34,220 --> 00:33:39,100
>> Ni inaweza kuchukua mbili, au tatu, au zaidi, kama
kwamba pili, au ya tatu, au nne,

694
00:33:39,100 --> 00:33:42,320
ni majina yote ya vigezo,
au hasa maadili,

695
00:33:42,320 --> 00:33:48,610
kwamba unataka kuziba katika,
dynamically, kwamba kamba katika quotes.

696
00:33:48,610 --> 00:33:52,110
Kwa maneno mengine, kile
itakuwa ni makosa na hili?

697
00:33:52,110 --> 00:33:57,920
Kama mimi tu kusema habari jina, backslash
n, kuokolewa faili yangu, ulioandaliwa kanuni yangu,

698
00:33:57,920 --> 00:34:01,660
na mbio hii, nini kitatokea?

699
00:34:01,660 --> 00:34:05,139
>> Ni tu kwenda kusema, hello
jina, literally N-A-M-E,

700
00:34:05,139 --> 00:34:07,900
ambayo ni aina ya kijinga kwa sababu
ni hakuna tofauti na ulimwengu.

701
00:34:07,900 --> 00:34:10,400
Hivyo chochote katika quotes ni
nini literally anapata kuchapishwa.

702
00:34:10,400 --> 00:34:12,520
Hivyo kama mimi nataka kuwa na
placeholder huko,

703
00:34:12,520 --> 00:34:14,422
Mimi kwa kweli haja ya kutumia
baadhi syntax maalum.

704
00:34:14,422 --> 00:34:17,380
Na zinageuka kama kusoma
nyaraka kwa ajili ya kazi printf,

705
00:34:17,380 --> 00:34:21,320
itakuambia kwamba
kama wewe kutumia asilimia s,

706
00:34:21,320 --> 00:34:23,920
unaweza kubadilisha thamani kama ifuatavyo.

707
00:34:23,920 --> 00:34:27,190
>> Baada ya comma baada ya kuwa
mara mbili quote, wewe tu

708
00:34:27,190 --> 00:34:29,179
kuandika jina la
kutofautiana kwamba unataka

709
00:34:29,179 --> 00:34:33,790
kuziba katika ndani ya muundo kwamba
kanuni, au format specifier,

710
00:34:33,790 --> 00:34:35,469
asilimia s kwa masharti.

711
00:34:35,469 --> 00:34:39,190
Na sasa kama mimi wameweza kuokolewa faili yangu,
Mimi kwenda nyuma chini ya terminal yangu.

712
00:34:39,190 --> 00:34:42,870
Na mimi aina Tengeneza Kamba,
kwa sababu, tena, jina la hii

713
00:34:42,870 --> 00:34:45,510
file kwamba mimi waliamua kabla ni string.c.

714
00:34:45,510 --> 00:34:48,510
>> Hivyo mimi nina kwenda kusema Tengeneza Kamba, kuingia.

715
00:34:48,510 --> 00:34:51,550
Oh wangu wema, kuangalia yote ya
makosa tumekuwa alifanya tayari.

716
00:34:51,550 --> 00:34:55,540
Na hii is-- nini, hii ni kweli
kama sita, saba line mpango?

717
00:34:55,540 --> 00:34:57,790
Hivyo hii ni mahali ambapo unaweza sana
haraka kupata balaa.

718
00:34:57,790 --> 00:35:00,890
>> Hii dirisha terminal ina
sasa tu regurgitated

719
00:35:00,890 --> 00:35:03,230
idadi kubwa ya ujumbe wa makosa.

720
00:35:03,230 --> 00:35:07,560
Hakika, sina makosa zaidi
ujumbe kuliko mimi mstari wa kanuni.

721
00:35:07,560 --> 00:35:08,680
Kwa hiyo kile kinachoendelea?

722
00:35:08,680 --> 00:35:10,920
>> Naam, mkakati bora
kufanya wakati wowote

723
00:35:10,920 --> 00:35:13,710
je kukutana balaa
orodha ya makosa kama hicho,

724
00:35:13,710 --> 00:35:16,690
ni kitabu nyuma, kuangalia kwa amri
wewe tu mbio, ambayo katika kesi yangu

725
00:35:16,690 --> 00:35:18,020
ni kufanya kamba.

726
00:35:18,020 --> 00:35:21,630
Kuangalia nini kufanya hivyo, na hiyo ni kwamba
muda mrefu Clang amri, hakuna mpango mkubwa huko.

727
00:35:21,630 --> 00:35:22,950
>> Lakini nyekundu ni mbaya.

728
00:35:22,950 --> 00:35:24,750
Green ni kujaribu kuwa
mpole na kusaidia.

729
00:35:24,750 --> 00:35:26,140
Lakini bado ni mbaya, katika kesi hii.

730
00:35:26,140 --> 00:35:27,510
Lakini ambapo ni mbaya?

731
00:35:27,510 --> 00:35:31,450
>> String.c, line tano, tabia ya tano.

732
00:35:31,450 --> 00:35:32,930
Hivyo hii ni tu ya kawaida mkataba.

733
00:35:32,930 --> 00:35:36,060
Kitu colon kitu ina maana
line idadi na idadi tabia.

734
00:35:36,060 --> 00:35:41,080
Kosa, matumizi ya Undeclared
kitambulisho kamba.

735
00:35:41,080 --> 00:35:42,900
Je, maana ya kiwango katika?

736
00:35:42,900 --> 00:35:45,530
>> Hivyo, kwa bahati mbaya, Clang
ni kujaribu kuwa na manufaa.

737
00:35:45,530 --> 00:35:46,850
Lakini ni makosa, katika kesi hii.

738
00:35:46,850 --> 00:35:49,350
Hakuna, Clang, sikuwa na maana kiwango cha IO.

739
00:35:49,350 --> 00:35:51,070
Mimi maana kwamba kwenye mstari mmoja, ndiyo.

740
00:35:51,070 --> 00:35:53,420
>> Lakini mstari tano ni hii moja hapa.

741
00:35:53,420 --> 00:35:57,040
Na Clang hana
kuelewa S-T-R-I-N-G.

742
00:35:57,040 --> 00:36:01,490
Ni Undeclared kitambulisho, a
neno ni tu hajawahi kuona mbele.

743
00:36:01,490 --> 00:36:05,730
Na kwamba kwa sababu C, lugha
sisi ni kuandika code katika haki sasa,

744
00:36:05,730 --> 00:36:08,070
hana vigezo inaitwa masharti.

745
00:36:08,070 --> 00:36:11,380
>> Hana, by default, msaada
kitu kinachoitwa kamba.

746
00:36:11,380 --> 00:36:16,750
Hiyo ni CS50 kipande cha
jargon, lakini kawaida sana.

747
00:36:16,750 --> 00:36:18,600
Lakini siwezi kurekebisha hili kama ifuatavyo.

748
00:36:18,600 --> 00:36:22,090
>> Kama mimi kuongeza line moja ya kanuni
juu ya mpango huu,

749
00:36:22,090 --> 00:36:27,890
pamoja na CS50.h, ambayo ni faili mwingine
mahali fulani ndani ya CS50 IDE, mahali fulani

750
00:36:27,890 --> 00:36:30,820
kwenye gari ngumu, hivyo kusema,
ya Ubuntu mfumo wa uendeshaji

751
00:36:30,820 --> 00:36:33,590
kwamba mimi nina mbio, kwamba
ni file hiyo ni

752
00:36:33,590 --> 00:36:38,740
kwenda kufundisha uendeshaji
mfumo kile kamba ni, tu

753
00:36:38,740 --> 00:36:41,930
kama kiwango io.h ni file
katika mfumo wa uendeshaji ambayo ni

754
00:36:41,930 --> 00:36:44,430
kwenda kufundisha ni nini printf.

755
00:36:44,430 --> 00:36:46,810
>> Hakika, sisi ingekuwa waliopata
ujumbe sawa sana

756
00:36:46,810 --> 00:36:50,600
kama IO alikiri kiwango cha
Io.h na walijaribu kutumia printf.

757
00:36:50,600 --> 00:36:53,632
Hivyo mimi nina kwenda mbele na tu
kuchukua Control L wazi screen yangu.

758
00:36:53,632 --> 00:36:56,340
Au unaweza aina wazi na itakuwa
tu wazi dirisha terminal.

759
00:36:56,340 --> 00:36:58,020
Lakini bado unaweza kitabu nyuma katika wakati.

760
00:36:58,020 --> 00:37:01,100
>> Na mimi nina kwenda kwa rerun Tengeneza String.

761
00:37:01,100 --> 00:37:03,660
Kuvuka vidole yangu wakati huu, kuingia.

762
00:37:03,660 --> 00:37:05,380
Oh, Mungu wangu, ni kazi.

763
00:37:05,380 --> 00:37:09,280
inaonyesha me kwa muda mrefu cryptic amri
kwamba ni nini Kufanya yanayotokana kupitia Clang,

764
00:37:09,280 --> 00:37:10,460
lakini ujumbe hakuna kosa.

765
00:37:10,460 --> 00:37:12,460
Hivyo kutambua, ingawa
unaweza kupata kabisa

766
00:37:12,460 --> 00:37:14,480
kuzidiwa na
idadi ya ujumbe wa makosa,

767
00:37:14,480 --> 00:37:17,540
ni tu inaweza kuwa hii kuachia annoying
athari, ambapo Clang haelewi

768
00:37:17,540 --> 00:37:19,620
jambo moja, maana yake basi
haelewi neno ijayo,

769
00:37:19,620 --> 00:37:20,560
au mstari wa pili.

770
00:37:20,560 --> 00:37:22,850
Na hivyo tu kwama kooni juu ya kanuni yako.

771
00:37:22,850 --> 00:37:24,440
Lakini fix inaweza kuwa rahisi.

772
00:37:24,440 --> 00:37:27,822
Na hivyo daima kuzingatia
mstari wa kwanza kabisa wa pato.

773
00:37:27,822 --> 00:37:29,530
Na kama huna
kuelewa, tu kuangalia

774
00:37:29,530 --> 00:37:32,480
kwa maneno ambayo inaweza kuwa
dalili, na idadi line,

775
00:37:32,480 --> 00:37:34,650
na tabia, ambapo
kwamba kosa inaweza kuwa.

776
00:37:34,650 --> 00:37:40,328
>> Sasa basi mimi kwenda mbele na aina
dot kufyeka, kamba, kuingia.

777
00:37:40,328 --> 00:37:44,340
Hm, siyo kusema hello kitu chochote.

778
00:37:44,340 --> 00:37:46,210
Kwa nini?

779
00:37:46,210 --> 00:37:48,170
Naam, kukumbuka, ambapo ni mbio?

780
00:37:48,170 --> 00:37:53,730
>> Ni pengine kukwama kwa wakati
katika kitanzi, kama wewe, juu ya mstari sita,

781
00:37:53,730 --> 00:37:56,950
kwa sababu Kupata String kwa kubuni,
zilizoandikwa na wafanyakazi CS50,

782
00:37:56,950 --> 00:38:00,350
ni halisi maana ya kukaa tu
hapo kusubiri, na kusubiri,

783
00:38:00,350 --> 00:38:01,850
na kusubiri kwa kamba.

784
00:38:01,850 --> 00:38:03,792
All maana sisi na kamba ni pembejeo za binadamu.

785
00:38:03,792 --> 00:38:04,500
Hivyo unajua nini?

786
00:38:04,500 --> 00:38:05,166
Hebu kwenda mbele.

787
00:38:05,166 --> 00:38:08,704
Na tu juu ya whim, napenda
kuandika jina langu, David, kuingia.

788
00:38:08,704 --> 00:38:10,120
Sasa nina mpango nguvu zaidi.

789
00:38:10,120 --> 00:38:11,240
Ilisema, hujambo Daudi.

790
00:38:11,240 --> 00:38:16,280
>> Kama mimi kwenda mbele na kukimbia hii tena,
basi mimi kujaribu kusema Zamila jina, kuingia.

791
00:38:16,280 --> 00:38:17,940
Na sasa tuna mpango wa nguvu.

792
00:38:17,940 --> 00:38:19,380
Mimi si ngumu coded dunia.

793
00:38:19,380 --> 00:38:21,760
Mimi si ngumu coded
jina, au David, au Zamila.

794
00:38:21,760 --> 00:38:25,350
>> Sasa ni mengi zaidi kama mipango
tunajua, ambapo kama kuchukua pembejeo,

795
00:38:25,350 --> 00:38:27,870
inazalisha pato tofauti kidogo.

796
00:38:27,870 --> 00:38:31,020
Sasa, hii si bora
user uzoefu, au UX.

797
00:38:31,020 --> 00:38:33,000
Mimi kuendesha programu.

798
00:38:33,000 --> 00:38:35,830
>> Sijui nini natakiwa
kufanya, isipokuwa mimi kweli kuangalia

799
00:38:35,830 --> 00:38:37,290
au kukumbuka chanzo kanuni.

800
00:38:37,290 --> 00:38:39,640
Basi hebu kufanya user
uzoefu kidogo bora

801
00:38:39,640 --> 00:38:41,240
na rahisi ya mambo.

802
00:38:41,240 --> 00:38:44,782
Hebu kwenda nyuma katika hii
mpango, na tu kusema printf.

803
00:38:44,782 --> 00:38:48,870
>> Na napenda kwenda mbele na kusema jina, koloni,
na nafasi, na kisha nusu koloni.

804
00:38:48,870 --> 00:38:51,170
Na tu kwa ajili mateke, hakuna n kuwepo kwa kuzorota.

805
00:38:51,170 --> 00:38:52,980
Na kwamba ni makusudi,
kwa sababu mimi sitaki

806
00:38:52,980 --> 00:38:54,590
haraka hoja ya mstari wa pili.

807
00:38:54,590 --> 00:38:58,800
>> Nataka, badala yake, kufanya hivyo, kufanya kamba
recompile kificho wangu katika mashine mpya

808
00:38:58,800 --> 00:39:00,980
kificho dot kufyeka kamba.

809
00:39:00,980 --> 00:39:02,460
Ah, hii ni kiasi prettier.

810
00:39:02,460 --> 00:39:05,780
Sasa ninajua hakika kile kompyuta
anataka nifanye, kuwapa jina.

811
00:39:05,780 --> 00:39:10,020
>> Hivyo mimi nina kwenda mbele na aina
katika Rob, kuingia, na hello, Rob.

812
00:39:10,020 --> 00:39:13,640
Hivyo, kutambua, hii bado ni, mwishoni
wa siku, tu mpango tisa line.

813
00:39:13,640 --> 00:39:15,090
Lakini tumekuwa kuchukuliwa hatua hizi mtoto.

814
00:39:15,090 --> 00:39:18,380
>> Tuliandika line moja ambayo sisi
walikuwa na mazoea, printf, hello dunia.

815
00:39:18,380 --> 00:39:19,980
Kisha sisi undid kidogo ya hiyo.

816
00:39:19,980 --> 00:39:21,560
Na sisi kweli kutumika kupata kamba.

817
00:39:21,560 --> 00:39:23,362
Na sisi kuchafuka kwamba thamani katika kutofautiana.

818
00:39:23,362 --> 00:39:26,070
Na kisha sisi akaenda mbele na kuboresha
ni zaidi na mstari wa tatu.

819
00:39:26,070 --> 00:39:29,220
Na mchakato huu iterative ya
kuandika programu ni kweli muhimu.

820
00:39:29,220 --> 00:39:33,420
Katika CS50, na katika maisha kwa ujumla,
unapaswa ujumla sio kukaa chini,

821
00:39:33,420 --> 00:39:36,800
kuwa na mpango katika akili, na kujaribu kuandika
nzima damn kitu wote mara moja.

822
00:39:36,800 --> 00:39:40,810
>> Itakuwa, inevitably, kusababisha njia
makosa zaidi ya sisi wenyewe waliona hapa.

823
00:39:40,810 --> 00:39:44,070
Hata mimi, leo hii, daima
kufanya makosa mengine ya kijinga,

824
00:39:44,070 --> 00:39:47,480
ni makosa kweli vigumu
kwamba ni vigumu kufikiri.

825
00:39:47,480 --> 00:39:52,095
Lakini utakuwa kufanya makosa zaidi zaidi
mstari wa kanuni kuandika wote mara moja.

826
00:39:52,095 --> 00:39:54,220
Na hivyo hii mazoezi ya,
kuandika kidogo ya kificho

827
00:39:54,220 --> 00:39:57,930
kwamba wewe ni starehe na, kukusanya
yake, kukimbia, mtihani kwa ujumla zaidi,

828
00:39:57,930 --> 00:40:01,370
kisha kuondoka on-- hivyo tu kama tuliendelea
layering na layering wiki iliyopita,

829
00:40:01,370 --> 00:40:04,190
kujenga kutoka kitu sana
rahisi kitu ngumu zaidi,

830
00:40:04,190 --> 00:40:05,200
kufanya hivyo hapa.

831
00:40:05,200 --> 00:40:08,500
Je, si kukaa chini, na kujaribu
kuandika tatizo nzima.

832
00:40:08,500 --> 00:40:10,780
Kwa kweli kuchukua hatua hizi mtoto.

833
00:40:10,780 --> 00:40:15,100
>> Sasa, masharti ni si wote
kwamba muhimu kwa ajili yao wenyewe.

834
00:40:15,100 --> 00:40:18,210
Tunatarajia kweli, walau, kama kwa
na kitu kingine katika toolkit yetu.

835
00:40:18,210 --> 00:40:20,990
Basi hebu kweli kufanya hasa kwamba.

836
00:40:20,990 --> 00:40:24,900
>> Hebu kwenda mbele sasa na mjeledi juu
mpango tofauti kidogo.

837
00:40:24,900 --> 00:40:28,320
Na tutaweza kuwaita int.c hii, kwa integer.

838
00:40:28,320 --> 00:40:30,870
Mimi nina kwenda, vile vile,
pamoja na CS550.h.

839
00:40:30,870 --> 00:40:33,060
Mimi nina kwenda pamoja na kiwango IO.

840
00:40:33,060 --> 00:40:36,630
Na kwamba ni kwenda kuwa pretty kawaida
katika siku hizi chache kwanza ya darasa.

841
00:40:36,630 --> 00:40:39,050
>> Na mimi nina kwenda kwa tayari
mwenyewe na kazi kuu.

842
00:40:39,050 --> 00:40:43,370
Na sasa badala ya kupata kamba,
hebu kwenda mbele na kupata int.

843
00:40:43,370 --> 00:40:49,285
Hebu simu yake i, na kuiita kupata
int, parens karibu, nusu koloni.

844
00:40:49,285 --> 00:40:51,410
Na sasa hebu kufanya
kitu kwa hayo, printf.

845
00:40:51,410 --> 00:40:56,190
>> Hebu kusema kitu kama
hello, backslash n, comma i.

846
00:40:56,190 --> 00:41:00,010
Hivyo mimi nina pretty much mimicking
nilivyopatenda muda tu iliyopita.

847
00:41:00,010 --> 00:41:01,660
Nina placeholder hapa.

848
00:41:01,660 --> 00:41:05,150
Mimi comma i hapa, kwa sababu nataka
kuziba i katika placeholder hiyo.

849
00:41:05,150 --> 00:41:07,250
>> Basi hebu kwenda mbele na kujaribu
kuandaa mpango huu.

850
00:41:07,250 --> 00:41:10,060
file inaitwa int.c.

851
00:41:10,060 --> 00:41:12,920
Hivyo mimi nina kwenda kusema, kufanya int, kuingia.

852
00:41:12,920 --> 00:41:16,420
Oh, Mungu wangu, lakini hakuna mpango mkubwa, haki?

853
00:41:16,420 --> 00:41:17,230
Kuna makosa.

854
00:41:17,230 --> 00:41:19,810
>> Kuna makosa kisintaksia
hapa kama kwamba mpango hawawezi

855
00:41:19,810 --> 00:41:25,460
kuwa ulioandaliwa ndani ya int.c, line
saba, tabia ya 27, kosa format

856
00:41:25,460 --> 00:41:28,400
bayana aina char
nyota, chochote kile.

857
00:41:28,400 --> 00:41:30,020
Lakini aina Hoja ni int.

858
00:41:30,020 --> 00:41:33,110
>> Hivyo hapa, pia, sisi siyo kwenda to--
ingawa leo ni mengi ya vifaa,

859
00:41:33,110 --> 00:41:35,710
tunakwenda overwhelm kwa
kabisa kila kipengele cha C,

860
00:41:35,710 --> 00:41:38,070
na programu zaidi kwa ujumla,
katika tu hizi wiki chache za kwanza.

861
00:41:38,070 --> 00:41:40,400
Kwa hiyo, kuna mara nyingi kwenda kuwa jargon
na ambayo wewe si ukoo.

862
00:41:40,400 --> 00:41:43,350
Na, kwa kweli, nyota char ni kitu
tunakwenda kurudi

863
00:41:43,350 --> 00:41:44,830
katika wiki au wakati mbili ya.

864
00:41:44,830 --> 00:41:47,530
>> Lakini kwa sasa, hebu angalia kama tunaweza
Hazrat maneno ambayo ni ya ukoo.

865
00:41:47,530 --> 00:41:50,750
Miundo tofauti-- hivyo tumesikia format
specifier, format kificho kabla.

866
00:41:50,750 --> 00:41:51,840
Hiyo ni ukoo.

867
00:41:51,840 --> 00:41:53,840
Type-- lakini hoja ina aina int.

868
00:41:53,840 --> 00:41:55,980
Hebu subiri kidogo, i ni int.

869
00:41:55,980 --> 00:41:59,230
>> Labda asilimia s kweli
ina baadhi ya maana defined.

870
00:41:59,230 --> 00:42:00,230
Na, kwa hakika, ni gani.

871
00:42:00,230 --> 00:42:03,101
integer, kama unataka
printf mbadala hilo,

872
00:42:03,101 --> 00:42:05,350
wewe kweli kuwa kutumia
tofauti format specifier.

873
00:42:05,350 --> 00:42:06,890
Na bila kujua hii
isipokuwa mtu niliwaambia,

874
00:42:06,890 --> 00:42:07,973
au wewe alikuwa amefanya hivyo kabla.

875
00:42:07,973 --> 00:42:10,490
Lakini asilimia i ni nini
inaweza kawaida kutumika

876
00:42:10,490 --> 00:42:12,240
katika printf kwa plugging katika integer.

877
00:42:12,240 --> 00:42:14,920
Unaweza pia kutumia asilimia
d kwa integer decimal.

878
00:42:14,920 --> 00:42:16,490
Lakini i ni nzuri na rahisi hapa.

879
00:42:16,490 --> 00:42:17,590
Hivyo tutaweza kwenda na kwamba.

880
00:42:17,590 --> 00:42:21,160
>> Sasa basi mimi kwenda mbele na
rerun kufanya int, kuingia.

881
00:42:21,160 --> 00:42:23,328
Hiyo ni nzuri, hakuna makosa.

882
00:42:23,328 --> 00:42:27,260
Dot kufyeka int OK, mbaya user uzoefu,
kwa sababu mimi si aliiambia mwenyewe

883
00:42:27,260 --> 00:42:27,760
nifanyeje.

884
00:42:27,760 --> 00:42:28,426
Lakini hiyo ni faini.

885
00:42:28,426 --> 00:42:29,480
Mimi nina kuambukizwa juu kwa haraka.

886
00:42:29,480 --> 00:42:36,260
>> Na sasa napenda kwenda mbele na
aina katika David, OK, Zamila, Rob.

887
00:42:36,260 --> 00:42:37,820
OK, hivyo hili ni jambo zuri.

888
00:42:37,820 --> 00:42:41,710
Wakati huu, mimi nina kutumia kazi,
puzzle kipande, iitwayo kupata int.

889
00:42:41,710 --> 00:42:44,230
Na ni zamu nje na tutaweza
kuona baadaye hii katika term--

890
00:42:44,230 --> 00:42:47,730
CS50 wafanyakazi imetekeleza
kupata kamba kwa namna

891
00:42:47,730 --> 00:42:50,350
kwamba itakuwa tu kimwili
kupata kamba kwa ajili yenu.

892
00:42:50,350 --> 00:42:54,340
>> Ni imetekeleza kupata int katika
namna kwamba itakuwa tu

893
00:42:54,340 --> 00:42:55,590
kupata integer kwa ajili yenu.

894
00:42:55,590 --> 00:42:57,830
Na kama wewe, binadamu,
hawana kushirikiana, ni

895
00:42:57,830 --> 00:43:00,590
literally tu kwenda
kusema retry, retry, retry,

896
00:43:00,590 --> 00:43:05,200
literally wamekaa looping, mpaka
wewe kumlazimu pamoja na baadhi ya idadi ya kichawi,

897
00:43:05,200 --> 00:43:07,670
kama 50, na hodi 50.

898
00:43:07,670 --> 00:43:11,440
>> Au kama sisi kukimbia hii tena
na aina katika 42, hello 42.

899
00:43:11,440 --> 00:43:15,750
Na hivyo kazi kupata int
ndani ya kwamba kipande puzzle

900
00:43:15,750 --> 00:43:19,050
ni mantiki ya kutosha, mawazo ya kutosha,
kufikiri, ndivyo neno?

901
00:43:19,050 --> 00:43:20,330
Na ni nini namba?

902
00:43:20,330 --> 00:43:23,165
kukubali tu, hatimaye, idadi.

903
00:43:23,165 --> 00:43:25,690

904
00:43:25,690 --> 00:43:30,230
>> Hivyo ni zinageuka kuwa hii
si yote expressive.

905
00:43:30,230 --> 00:43:30,910
kufikia hapa; kufikia sasa.

906
00:43:30,910 --> 00:43:33,690
Hivyo, yay, mara ya mwisho sisi
akaenda pretty haraka

907
00:43:33,690 --> 00:43:38,320
katika utekelezaji wa michezo, na uhuishaji,
na kazi za sanaa katika Scratch.

908
00:43:38,320 --> 00:43:42,260
Na hapa, sisi ni kuwa yaliyomo
na hujambo dunia, na hodi 50.

909
00:43:42,260 --> 00:43:43,696
>> Siyo msukumo kwamba wote.

910
00:43:43,696 --> 00:43:46,070
Na kwa kweli, hizi kwanza chache
mifano itachukua muda

911
00:43:46,070 --> 00:43:47,510
njia panda juu katika msisimko.

912
00:43:47,510 --> 00:43:49,854
Lakini tuna mambo mengi zaidi
kudhibiti sasa, kwa kweli.

913
00:43:49,854 --> 00:43:51,770
Na tunakwenda sana
haraka kuanza layering

914
00:43:51,770 --> 00:43:53,870
juu ya primitives haya ya msingi.

915
00:43:53,870 --> 00:43:56,370
>> Lakini kwanza, hebu kuelewa
nini mapungufu ni.

916
00:43:56,370 --> 00:43:58,620
Kwa kweli, moja ya mambo
Scratch hana urahisi

917
00:43:58,620 --> 00:44:00,990
hebu kufanya ni kweli kuangalia
chini ya Hood,

918
00:44:00,990 --> 00:44:03,740
na kuelewa nini
kompyuta ni, nini anaweza kufanya,

919
00:44:03,740 --> 00:44:05,250
na nini mapungufu yake ni.

920
00:44:05,250 --> 00:44:08,580
Na kwa kweli, kwamba ukosefu wa
uelewa, uwezekano, ya muda mrefu

921
00:44:08,580 --> 00:44:12,520
unaweza kusababisha mistakes-- kuandika yetu wenyewe
mende, kuandika programu usalama kwamba

922
00:44:12,520 --> 00:44:13,880
anapata hacked kwa namna fulani.

923
00:44:13,880 --> 00:44:17,130
>> Basi hebu kuchukua baadhi ya hatua kuelekea
kuelewa hili vizuri kidogo na

924
00:44:17,130 --> 00:44:19,710
njia ya, kusema, mfano zifuatazo.

925
00:44:19,710 --> 00:44:23,550
Mimi nina kwenda mbele na kutekeleza
halisi haraka mpango ujulikanao fira.

926
00:44:23,550 --> 00:44:25,134
Kama, hebu kuongeza idadi ya baadhi ya pamoja.

927
00:44:25,134 --> 00:44:27,800
Na mimi nina kwenda kwa kificho pembe baadhi
hapa, na tu nakala na kuweka

928
00:44:27,800 --> 00:44:30,270
ambapo mimi nilikuwa kabla, tu
ili tuweze kupata kwenda mapema.

929
00:44:30,270 --> 00:44:33,090
Hivyo sasa mimi nimepata mwanzo msingi
ya mpango ujulikanao fira.

930
00:44:33,090 --> 00:44:34,670
>> Na hebu kwenda mbele na kufanya hili.

931
00:44:34,670 --> 00:44:38,680
Mimi nina kwenda mbele na
kusema, intx anapata kupata int.

932
00:44:38,680 --> 00:44:39,430
Na unajua nini?

933
00:44:39,430 --> 00:44:40,990
Hebu kufanya bora user uzoefu.

934
00:44:40,990 --> 00:44:45,740
>> Hivyo hebu sema tu x ni, na kwa ufanisi
kuchochea mtumiaji kutupa x.

935
00:44:45,740 --> 00:44:50,600
Na kisha basi mimi kwenda mbele na kusema, printf
vipi kuhusu y ni, wakati huu wanatarajia

936
00:44:50,600 --> 00:44:53,140
maadili mbili kutoka kwa mtumiaji.

937
00:44:53,140 --> 00:44:59,759
Na kisha hebu tu kwenda mbele na
kusema, printf, jumla ya x na y ni.

938
00:44:59,759 --> 00:45:01,300
Na sasa mimi sitaki kufanya asilimia s.

939
00:45:01,300 --> 00:45:09,080
Nataka kufanya asilimia i, backslash
n, na kisha kuziba katika thamani jibu.

940
00:45:09,080 --> 00:45:10,620
>> Hivyo ni jinsi gani mimi kwenda juu ya kufanya hii?

941
00:45:10,620 --> 00:45:11,270
Unajua nini?

942
00:45:11,270 --> 00:45:12,840
Najua jinsi ya kutumia vigezo.

943
00:45:12,840 --> 00:45:15,140
Napenda tu kutangaza mwezi mmoja, int z.

944
00:45:15,140 --> 00:45:16,770
>> Na mimi nina kwenda kuchukua nadhani hapa.

945
00:45:16,770 --> 00:45:21,470
Kama kuna dalili sawa katika hili
lugha, labda naweza tu kufanya x plus y,

946
00:45:21,470 --> 00:45:23,660
muda mrefu kama mimi kuishia yangu
mawazo na nusu koloni?

947
00:45:23,660 --> 00:45:28,170
Sasa naweza kwenda nyuma chini hapa, kuziba katika z,
kumaliza wazo hili na nusu koloni.

948
00:45:28,170 --> 00:45:33,160
Na hebu angalia sasa, kama hawa
Utaratibu wa lines-- x ni kupata int.

949
00:45:33,160 --> 00:45:34,770
Y ni kupata int.

950
00:45:34,770 --> 00:45:37,980
>> Kuongeza x na y, kuhifadhi thamani katika z--
hivyo, tena, kumbuka ishara sawa

951
00:45:37,980 --> 00:45:38,560
si sawa.

952
00:45:38,560 --> 00:45:41,100
Ni zoezi kutoka kulia kwenda kushoto.

953
00:45:41,100 --> 00:45:45,180
Na hebu magazeti nje kwamba jumla
ya x na y ni si halisi z,

954
00:45:45,180 --> 00:45:46,830
lakini nini ndani ya z.

955
00:45:46,830 --> 00:45:50,090
Basi hebu kufanya fira -
nzuri, hakuna makosa wakati huu.

956
00:45:50,090 --> 00:45:53,030
Dot kufyeka fira, kuingia,
x ni kwenda kuwa 1.

957
00:45:53,030 --> 00:45:55,380
>> Y ni kwenda kuwa 2.

958
00:45:55,380 --> 00:45:58,964
Na jumla ya x na y ni 3.

959
00:45:58,964 --> 00:46:00,130
Basi hiyo ni yote faini na nzuri.

960
00:46:00,130 --> 00:46:03,260
>> Hivyo ungependa kufikiria kwamba math
wanapaswa kufanya kazi katika mpango kama hii.

961
00:46:03,260 --> 00:46:04,040
Lakini unajua nini?

962
00:46:04,040 --> 00:46:06,904
Je, hii ni kutofautiana, line
12, hata muhimu?

963
00:46:06,904 --> 00:46:09,820
Huwezi haja ya kupata katika tabia
ya tu kuhifadhi vitu katika vigezo

964
00:46:09,820 --> 00:46:10,980
kwa sababu tu unaweza.

965
00:46:10,980 --> 00:46:13,550
Na, kwa kweli, ni kwa ujumla
aliichukulia kubuni mbaya

966
00:46:13,550 --> 00:46:18,100
kama wewe ni kujenga variable, kuitwa
z katika kesi hii, kuhifadhi kitu ndani yake,

967
00:46:18,100 --> 00:46:21,390
na kisha mara moja
kutumia, lakini kamwe tena.

968
00:46:21,390 --> 00:46:24,700
Kwa nini kutoa kitu jina
kama z kama uko literally

969
00:46:24,700 --> 00:46:26,770
kwenda kutumia kwamba
Jambo moja tu, na hivyo

970
00:46:26,770 --> 00:46:29,380
kupakana na ambapo wewe uliumba
katika nafasi ya kwanza,

971
00:46:29,380 --> 00:46:31,052
hivyo karibu katika suala la mstari wa kanuni?

972
00:46:31,052 --> 00:46:31,760
Hivyo unajua nini?

973
00:46:31,760 --> 00:46:34,480
Ni zinageuka kuwa C ni pretty rahisi.

974
00:46:34,480 --> 00:46:36,586
Kama mimi kwa kweli wanataka
kuziba-katika maadili hapa,

975
00:46:36,586 --> 00:46:38,210
Sina haja ya kutangaza kutofautiana mpya.

976
00:46:38,210 --> 00:46:41,680
Mimi naweza kuziba-katika tu x plus
y, kwa sababu C anaelewa

977
00:46:41,680 --> 00:46:43,390
hesabu, na watoa huduma za hesabu.

978
00:46:43,390 --> 00:46:47,140
>> Hivyo siwezi tu kusema, kufanya hesabu hii,
x plus y, chochote maadili hayo ni,

979
00:46:47,140 --> 00:46:50,780
kuziba na kusababisha
integer katika kamba hiyo.

980
00:46:50,780 --> 00:46:53,730
Hivyo hii inaweza kuwa, ingawa
tu mstari mmoja mfupi,

981
00:46:53,730 --> 00:46:58,480
kubuni bora, mpango bora,
kwa sababu kuna chini kificho, kwa hiyo

982
00:46:58,480 --> 00:46:59,921
chini kwa mimi kuelewa.

983
00:46:59,921 --> 00:47:01,920
Na pia ni safi tu,
kadiri sisi siyo

984
00:47:01,920 --> 00:47:04,620
kuanzisha maneno mapya,
alama mpya, kama z,

985
00:47:04,620 --> 00:47:07,510
ingawa wao si kweli
kutumikia sehemu kubwa ya kusudi.

986
00:47:07,510 --> 00:47:12,890
>> Kwa bahati mbaya, math si
kwamba kuaminika wakati mwingine wote.

987
00:47:12,890 --> 00:47:15,270
Hebu kwenda mbele na kufanya hili.

988
00:47:15,270 --> 00:47:18,200
Mimi nina kwenda mbele
sasa na kufanya yafuatayo.

989
00:47:18,200 --> 00:47:27,650
>> Hebu kufanya printf, asilimia i, pamoja na asilimia
i, kitakuwa asilimia i, backslash n.

990
00:47:27,650 --> 00:47:32,240
Na mimi nina kwenda kufanya Haya xyx plus y.

991
00:47:32,240 --> 00:47:34,821
Hivyo mimi nina kwenda tu kuandika upya
hii tofauti kidogo hapa.

992
00:47:34,821 --> 00:47:36,320
Napenda tu kufanya haraka sanity hundi.

993
00:47:36,320 --> 00:47:37,986
Tena, hebu si kupata mbele ya sisi wenyewe.

994
00:47:37,986 --> 00:47:41,420
Kufanya fira, dot kufyeka fira.

995
00:47:41,420 --> 00:47:44,950
x ni 1, y ni 2, 1 plus 2 ni 3.

996
00:47:44,950 --> 00:47:45,870
Hivyo hiyo ni nzuri.

997
00:47:45,870 --> 00:47:49,060
Lakini hebu magumu hili sasa
bit, na kuunda faili mpya.

998
00:47:49,060 --> 00:47:53,350
>> Mimi nina kwenda kuwaita hii moja,
kusema, ints, wingi kwa integers.

999
00:47:53,350 --> 00:47:55,980
Napenda kuanza ambapo mimi nilikuwa wakati iliyopita.

1000
00:47:55,980 --> 00:47:57,770
Lakini sasa hebu kufanya chache mistari mingine.

1001
00:47:57,770 --> 00:48:03,430
Hebu kwenda mbele na kufanya yafuatayo,
printf, asilimia i, bala asilimia i,

1002
00:48:03,430 --> 00:48:08,959
ni asilimia i, comma x, comma YX minus y.

1003
00:48:08,959 --> 00:48:10,750
Hivyo mimi nina kufanya kidogo
tofauti math huko.

1004
00:48:10,750 --> 00:48:11,624
Hebu kufanya mwingine mmoja.

1005
00:48:11,624 --> 00:48:16,610
Hivyo asilimia i mara asilimia
i ni asilimia i, backslash n.

1006
00:48:16,610 --> 00:48:21,430
Hebu kuziba-katika x, na y, na mara x y.

1007
00:48:21,430 --> 00:48:24,530
Tutaweza kutumia asteriski juu ya
kompyuta yako kwa mara.

1008
00:48:24,530 --> 00:48:26,390
>> Huwezi kutumia x. x ni
jina kutofautiana hapa.

1009
00:48:26,390 --> 00:48:28,270
Wewe kutumia nyota kwa kuzidisha.

1010
00:48:28,270 --> 00:48:29,020
Hebu kufanya moja zaidi.

1011
00:48:29,020 --> 00:48:34,580
Printf asilimia mimi, umegawanyika
kwa asilimia i, ni asilimia i,

1012
00:48:34,580 --> 00:48:40,460
backslash n. xy kugawanywa na y--
hivyo kutumia kufyeka mbele katika C

1013
00:48:40,460 --> 00:48:41,502
kufanya mgawanyiko.

1014
00:48:41,502 --> 00:48:42,460
Na hebu kufanya moja nyingine.

1015
00:48:42,460 --> 00:48:47,920

1016
00:48:47,920 --> 00:48:55,240
Salio ya asilimia i, umegawanyika
kwa asilimia i, ni asilimia i.

1017
00:48:55,240 --> 00:48:59,550
xy-- na sasa salio
ni nini kushoto juu.

1018
00:48:59,550 --> 00:49:02,980
Unapojaribu kugawa
denominator katika kadiri,

1019
00:49:02,980 --> 00:49:05,570
ni kiasi gani kushoto juu ya kwamba
wewe hakuweza kugawanya nje?

1020
00:49:05,570 --> 00:49:07,910
>> Kwa hiyo, kuna si kweli,
lazima, alama

1021
00:49:07,910 --> 00:49:09,470
tumekuwa kutumika katika shule ya daraja kwa hili.

1022
00:49:09,470 --> 00:49:13,830
Lakini kuna katika C. Unaweza
kusema x modulo y, ambapo

1023
00:49:13,830 --> 00:49:18,000
hii ni ishara asilimia katika context-- hii
confusingly wakati uko ndani ya

1024
00:49:18,000 --> 00:49:20,170
ya quotes mbili,
ndani ya printf, asilimia

1025
00:49:20,170 --> 00:49:21,830
hutumika kama format specifier.

1026
00:49:21,830 --> 00:49:25,420
>> Wakati matumizi ya asilimia nje ya
kwamba katika kujieleza hisabati,

1027
00:49:25,420 --> 00:49:29,910
ni modulo operator kwa msimu
arithmetic-- kwa madhumuni yetu

1028
00:49:29,910 --> 00:49:33,650
hapa, ina maana tu, ni nini
salio ya x kugawanywa na y?

1029
00:49:33,650 --> 00:49:36,130
Hivyo x kugawanywa na y ni x kufyeka y.

1030
00:49:36,130 --> 00:49:38,220
Nini salio ya x kugawanywa na y?

1031
00:49:38,220 --> 00:49:41,780
Ni x mod y, kama programu kusema.

1032
00:49:41,780 --> 00:49:48,300
>> Hivyo kama mimi alifanya makosa hapa, napenda
kwenda mbele na kufanya ints, wingi, nzuri,

1033
00:49:48,300 --> 00:49:50,010
na dot kufyeka ints.

1034
00:49:50,010 --> 00:49:55,270
Na hebu kwenda mbele na
kufanya, hebu sema, 1, 10.

1035
00:49:55,270 --> 00:49:58,390
Yote ya haki, 1 plus 10 ni 11, hundi.

1036
00:49:58,390 --> 00:50:01,240
1 minus 10 ni hasi 9, angalia.

1037
00:50:01,240 --> 00:50:03,420
>> 1 mara 10 ni 10, hundi.

1038
00:50:03,420 --> 00:50:07,090
1 kugawanywa na 10 is--
OK, tutaweza ruka kwamba moja.

1039
00:50:07,090 --> 00:50:09,480
Salio ya 1 kugawanywa na 10 ni 1.

1040
00:50:09,480 --> 00:50:10,680
Hiyo ni sahihi.

1041
00:50:10,680 --> 00:50:12,630
Lakini kuna mdudu katika hapa.

1042
00:50:12,630 --> 00:50:15,390
>> Hivyo moja mimi kuweka yangu
kukabidhi, si sahihi.

1043
00:50:15,390 --> 00:50:16,670
I mean, ni karibu na 0.

1044
00:50:16,670 --> 00:50:20,670
1 kugawanywa na 10, unajua, kama tuko
kukata pembe baadhi, hakika, ni sifuri.

1045
00:50:20,670 --> 00:50:28,050
Lakini ni lazima kweli kuwa 1/10,
0.1, au 0.10, 0.1000, ama kadhalika.

1046
00:50:28,050 --> 00:50:30,600
>> Ni lazima si kweli kuwa sifuri.

1047
00:50:30,600 --> 00:50:35,990
Naam, ni zamu nje kwamba kompyuta ni
kufanya literally nini tunaambiwa ni kufanya.

1048
00:50:35,990 --> 00:50:39,460
Sisi ni kufanya math kama x kugawanywa na y.

1049
00:50:39,460 --> 00:50:44,680
Na wote wawili x na y, per mistari
ya kificho awali, ni integers.

1050
00:50:44,680 --> 00:50:50,440
>> Aidha, katika mstari wa 15, sisi ni
kuwaambia printf, hey, printf kuziba-katika

1051
00:50:50,440 --> 00:50:54,230
integer, kuziba-katika integer,
kuziba-katika integer-- hasa

1052
00:50:54,230 --> 00:50:57,580
x, na kisha y, na kisha x
kugawanywa na y. x na y ni ints.

1053
00:50:57,580 --> 00:50:59,060
Sisi ni nzuri huko.

1054
00:50:59,060 --> 00:51:01,250
>> Lakini ni nini x kugawanywa na x?

1055
00:51:01,250 --> 00:51:06,790
x kugawanywa na y lazima,
kimahesabu, 1/10, au 0.1,

1056
00:51:06,790 --> 00:51:11,600
ambayo ni idadi halisi, idadi halisi
kuwa, uwezekano, uhakika decimal.

1057
00:51:11,600 --> 00:51:13,230
Siyo integer.

1058
00:51:13,230 --> 00:51:18,290
>> Lakini nini ni karibu
integer kwa 1/10, au 0.1?

1059
00:51:18,290 --> 00:51:21,114
Yeah, ni aina ya ni sifuri.

1060
00:51:21,114 --> 00:51:22,030
0.1 ni kama kiasi hiki.

1061
00:51:22,030 --> 00:51:22,890
Na 1 ni kiasi hiki.

1062
00:51:22,890 --> 00:51:25,870
Hivyo 1/10 ni karibu na
0 kuliko ilivyo kwa moja.

1063
00:51:25,870 --> 00:51:30,800
>> Na hivyo kile C ni kufanya kwa ajili us--
aina ya sababu tunaambiwa ni to--

1064
00:51:30,800 --> 00:51:32,600
ni truncating kwamba integer.

1065
00:51:32,600 --> 00:51:40,540
Ni kuchukua thamani, ambayo tena ni
wanatakiwa kuwa kitu kama 0.1000,

1066
00:51:40,540 --> 00:51:41,800
0 na kadhalika.

1067
00:51:41,800 --> 00:51:45,320
Na ni truncating kila kitu
baada ya uhakika decimal

1068
00:51:45,320 --> 00:51:47,510
ili yote haya
stuff, kwa sababu haina

1069
00:51:47,510 --> 00:51:51,910
fit katika dhana ya integer, ambayo
ni idadi tu kama hasi 1, 0, 1,

1070
00:51:51,910 --> 00:51:55,830
juu na chini, ni kumtupia mbali kila kitu
baada ya uhakika decimal sababu wewe

1071
00:51:55,830 --> 00:51:59,020
haziwezi kutosha uhakika decimal
katika integer kwa ufafanuzi.

1072
00:51:59,020 --> 00:52:01,290
>> Hivyo jibu hapa ni sifuri.

1073
00:52:01,290 --> 00:52:02,600
Hivyo ni jinsi gani sisi kurekebisha hili?

1074
00:52:02,600 --> 00:52:04,400
Tunahitaji ufumbuzi mwingine wote pamoja.

1075
00:52:04,400 --> 00:52:06,880
Na tunaweza kufanya hivyo, kama ifuatavyo.

1076
00:52:06,880 --> 00:52:12,820
>> Hebu kwenda mbele na kuunda mpya
file, hii mtu mmoja aitwaye floats.c.

1077
00:52:12,820 --> 00:52:16,500
Na ila ni hapa katika
saraka ya sawa, float.c.

1078
00:52:16,500 --> 00:52:19,360

1079
00:52:19,360 --> 00:52:23,260
Na napenda kwenda mbele na nakala
baadhi ya kwamba kanuni kutoka mapema.

1080
00:52:23,260 --> 00:52:27,690
>> Lakini badala ya kupata
int, hebu kufanya hili.

1081
00:52:27,690 --> 00:52:31,037
Nipe hatua yaliyo thamani
kuitwa x. ambapo yaliyo hatua

1082
00:52:31,037 --> 00:52:33,370
thamani ya kitu tu literally
kitu kwa yaliyo hatua.

1083
00:52:33,370 --> 00:52:34,410
Ni inaweza hoja ya kushoto, na haki.

1084
00:52:34,410 --> 00:52:35,530
Ni idadi halisi.

1085
00:52:35,530 --> 00:52:38,050
>> Na napenda kuwaita si
kupata int, lakini kupata kuelea,

1086
00:52:38,050 --> 00:52:41,420
ambayo pia alikuwa miongoni mwa orodha
ya chaguzi katika maktaba C250.

1087
00:52:41,420 --> 00:52:43,220
Hebu kubadili y kwa kuelea.

1088
00:52:43,220 --> 00:52:45,000
Hivyo hii inakuwa kupata kuelea.

1089
00:52:45,000 --> 00:52:47,620
>> Na sasa, hatutaki kuziba katika ints.

1090
00:52:47,620 --> 00:52:53,130
Ni zinageuka tuna kutumia asilimia
f kwa kuelea, asilimia f kwa kuelea,

1091
00:52:53,130 --> 00:52:54,560
na sasa kuiokoa.

1092
00:52:54,560 --> 00:53:01,220
Na sasa, vidole shilingi, kufanya
ikifungwa, nzuri, dot kufyeka ikifungwa.

1093
00:53:01,220 --> 00:53:04,280
x ni kwenda kuwa moja 1. y
Ni kwenda kuwa 10 tena.

1094
00:53:04,280 --> 00:53:08,240
>> Na, nzuri, OK Aidha yangu ni sahihi.

1095
00:53:08,240 --> 00:53:10,240
Mimi nilikuwa na matumaini kwa zaidi,
lakini mimi alisahau kuandika.

1096
00:53:10,240 --> 00:53:13,250
Basi hebu kwenda na kurekebisha hitilafu hii mantiki.

1097
00:53:13,250 --> 00:53:16,280
>> Hebu kwenda mbele na kunyakua zifuatazo.

1098
00:53:16,280 --> 00:53:18,080
Tutaweza tu kufanya nakala kidogo na kuweka.

1099
00:53:18,080 --> 00:53:20,080
Na mimi nina kwenda kusema bala.

1100
00:53:20,080 --> 00:53:21,890
>> Na mimi nina kwenda kusema mara.

1101
00:53:21,890 --> 00:53:24,060
Na mimi nina kwenda kwa kusema kugawanywa.

1102
00:53:24,060 --> 00:53:28,240
Na mimi nina si kwenda kufanya modulo,
ambayo si kama germane hapa,

1103
00:53:28,240 --> 00:53:33,690
kugawanywa na f, na mara plus
OK, hebu kufanya hili tena.

1104
00:53:33,690 --> 00:53:44,210
>> Kufanya ikifungwa, dot kufyeka ikifungwa,
na 1, 10, and-- nzuri, hapana, OK.

1105
00:53:44,210 --> 00:53:45,250
Kwa hiyo mimi nina idiot.

1106
00:53:45,250 --> 00:53:47,000
Hivyo hii ni ya kawaida sana
katika sayansi ya kompyuta

1107
00:53:47,000 --> 00:53:49,780
kufanya makosa ya kijinga kama hii.

1108
00:53:49,780 --> 00:53:53,100
>> Kwa madhumuni ya ufundishaji,
kile kweli alitaka kufanya

1109
00:53:53,100 --> 00:53:57,410
ilikuwa mabadiliko ya sayansi hapa
kwa pamoja, kwa bala, kwa nyakati,

1110
00:53:57,410 --> 00:54:01,140
na kugawanya, kama wewe hopefully
niliona wakati wa zoezi hili.

1111
00:54:01,140 --> 00:54:04,700
Hivyo sasa hebu re-kukusanya hii
mpango, kufanya dot kufyeka ikifungwa.

1112
00:54:04,700 --> 00:54:07,950
>> Na kwa mara ya tatu, hebu
kuona kama yanakidhi matarajio yangu.

1113
00:54:07,950 --> 00:54:21,480
1, 10, kuingia, ndiyo, OK, 1.000,
kugawanywa na 10.000, ni 0.100000.

1114
00:54:21,480 --> 00:54:24,952
Na zinageuka tunaweza kudhibiti jinsi wengi
idadi ni baada ya pointi hizo decimal.

1115
00:54:24,952 --> 00:54:25,660
Sisi kwa kweli mapenzi.

1116
00:54:25,660 --> 00:54:26,790
Tutaweza kuja nyuma na kwamba.

1117
00:54:26,790 --> 00:54:28,440
>> Lakini sasa, kwa kweli, math ni sahihi.

1118
00:54:28,440 --> 00:54:30,090
Hivyo, tena, nini takeaway hapa?

1119
00:54:30,090 --> 00:54:33,050
Ni zinageuka kuwa katika C, kuna
si tu tu strings-- na, kwa kweli,

1120
00:54:33,050 --> 00:54:36,120
kuna si kweli, kwa sababu sisi
kuongeza wale walio na maktaba CS50.

1121
00:54:36,120 --> 00:54:37,710
Lakini kuna si ints tu.

1122
00:54:37,710 --> 00:54:38,990
>> Kuna pia ikifungwa.

1123
00:54:38,990 --> 00:54:42,810
Na zinageuka rundo la data nyingine
aina pia kwamba, tutaweza kutumia kabla ya muda mrefu.

1124
00:54:42,810 --> 00:54:46,270
Zamu nje kama unataka single
tabia, si kamba ya wahusika,

1125
00:54:46,270 --> 00:54:47,610
unaweza kutumia tu char.

1126
00:54:47,610 --> 00:54:52,350
>> Zinageuka kuwa kama unataka bool,
thamani Boolean, kweli au uongo tu,

1127
00:54:52,350 --> 00:54:56,840
shukrani kwa maktaba CS50, tumekuwa
aliongeza kwa C aina bool data vilevile.

1128
00:54:56,840 --> 00:54:59,180
Lakini pia ni kuwasilisha katika
lugha nyingine nyingi kama vile.

1129
00:54:59,180 --> 00:55:04,130
Na zinageuka kuwa wakati mwingine wewe
haja idadi kubwa basi kuja na default

1130
00:55:04,130 --> 00:55:05,210
na ints na ikifungwa.

1131
00:55:05,210 --> 00:55:10,590
>> Na, kwa kweli, mara mbili ni idadi
ambayo inatumia si 32 bits, lakini 64 bits.

1132
00:55:10,590 --> 00:55:14,990
Na kwa muda mrefu kwa muda mrefu ni idadi hiyo
anatumia si 32, bits lakini 64 bits,

1133
00:55:14,990 --> 00:55:19,190
kwa mtiririko huo, kwa yaliyo hatua
maadili na integers, kwa mtiririko huo.

1134
00:55:19,190 --> 00:55:22,780
Basi hebu kweli sasa
Kuona hii katika hatua.

1135
00:55:22,780 --> 00:55:26,150
>> Mimi nina kwenda mbele hapa
na mjeledi juu ya mpango mwingine mmoja.

1136
00:55:26,150 --> 00:55:32,020
Hapa, mimi nina kwenda mbele
na wala ni pamoja na CS50.h.

1137
00:55:32,020 --> 00:55:34,910
Na napenda kwenda, ni pamoja na kiwango io.h.

1138
00:55:34,910 --> 00:55:37,320
>> Na wewe utakuwa taarifa kitu
funky kinachotokea hapa.

1139
00:55:37,320 --> 00:55:40,592
Ni si rangi coding mambo katika
njia ile ile kama ilivyokuwa kabla.

1140
00:55:40,592 --> 00:55:43,550
Na zinageuka, hiyo ni kwa sababu mimi
hawajakata jambo faili jina.

1141
00:55:43,550 --> 00:55:47,270
>> Mimi nina kwenda kuwaita hii moja
sizeof.c, na kugonga Hifadhi.

1142
00:55:47,270 --> 00:55:51,039
Na taarifa nini kinatokea kwa yangu sana
nyeupe kificho dhidi ya kwamba kuongezeka nyeusi.

1143
00:55:51,039 --> 00:55:52,830
Sasa, angalau kuna
baadhi zambarau katika huko.

1144
00:55:52,830 --> 00:55:54,490
Na ni syntax yalionyesha.

1145
00:55:54,490 --> 00:55:57,700
>> Hiyo ni kwa sababu, rahisi kabisa, nimekuwa
aliiambia IDE ni aina gani ya faili

1146
00:55:57,700 --> 00:56:01,060
ni kwa kutoa ni jina, na
hasa faili ugani.

1147
00:56:01,060 --> 00:56:03,620
Sasa, hebu kwenda mbele na kufanya hili.

1148
00:56:03,620 --> 00:56:08,910
Mimi nina kwenda mbele na sana
tu magazeti nje bool following--

1149
00:56:08,910 --> 00:56:11,080
ni asilimia LU.

1150
00:56:11,080 --> 00:56:12,950
>> Tutaweza kurudi kwa
kwamba katika muda tu.

1151
00:56:12,950 --> 00:56:15,840
Na kisha mimi nina kwenda
magazeti ukubwa wa bool.

1152
00:56:15,840 --> 00:56:18,170
Na sasa, tu kuokoa
mwenyewe baadhi ya wakati, mimi nina

1153
00:56:18,170 --> 00:56:20,280
kwenda kufanya nzima
rundo la hizo mara moja.

1154
00:56:20,280 --> 00:56:24,620
Na, hasa, mimi nina kwenda kwa
kubadili hali hii kwa char na char.

1155
00:56:24,620 --> 00:56:27,760
Hii moja, mimi nina kwenda na mabadiliko
kwa mara mbili na mara mbili.

1156
00:56:27,760 --> 00:56:31,440
>> Hii moja, mimi nina kwenda na mabadiliko
kwa kuelea na kuelea.

1157
00:56:31,440 --> 00:56:35,670
Hii moja, mimi nina kwenda kwa
mabadiliko ya int na int.

1158
00:56:35,670 --> 00:56:38,660
Na hii moja, mimi nina kwenda
na mabadiliko ya muda mrefu kwa muda mrefu.

1159
00:56:38,660 --> 00:56:40,840
Na ni bado kuchukua
muda mrefu, kwa muda mrefu kwa muda mrefu.

1160
00:56:40,840 --> 00:56:44,572
>> Na kisha, mwisho, mimi alitoa
mwenyewe moja wengi mno, kamba.

1161
00:56:44,572 --> 00:56:47,030
Ni zinageuka kuwa katika C, kuna
operator maalum iitwayo

1162
00:56:47,030 --> 00:56:50,260
ukubwa wa hiyo ni literally
kwenda, wakati kukimbia,

1163
00:56:50,260 --> 00:56:52,099
kutuambia ukubwa wa
kila mmoja vigezo hivi.

1164
00:56:52,099 --> 00:56:53,890
Na hii ni njia, sasa,
tunaweza kuungana nyuma

1165
00:56:53,890 --> 00:56:57,140
kwa majadiliano ya wiki iliyopita
ya data na uwakilishi.

1166
00:56:57,140 --> 00:57:00,330
>> Hebu kwenda mbele na kukusanya
ukubwa wa dot kufyeka ukubwa wa.

1167
00:57:00,330 --> 00:57:01,210
Na hebu angalia.

1168
00:57:01,210 --> 00:57:05,210
Ni zinageuka kuwa katika C,
hasa juu ya CS50 IDE,

1169
00:57:05,210 --> 00:57:08,170
hasa juu ya
mfumo wa uendeshaji Ubuntu,

1170
00:57:08,170 --> 00:57:11,100
ambayo ni 64-bit uendeshaji
mfumo katika kesi hii,

1171
00:57:11,100 --> 00:57:14,189
bool ni kwenda
kutumia Byte moja ya nafasi.

1172
00:57:14,189 --> 00:57:16,480
Hiyo ni jinsi ukubwa ni kipimo,
si katika bits, lakini katika ka.

1173
00:57:16,480 --> 00:57:18,690
Na kukumbuka kwamba byte moja ni bits nane.

1174
00:57:18,690 --> 00:57:22,030
Hivyo bool, hata kama wewe
kitaalam tu haja 0 au 1,

1175
00:57:22,030 --> 00:57:24,092
ni kidogo fujo
jinsi tumekuwa kutekelezwa yake.

1176
00:57:24,092 --> 00:57:26,800
Ni kweli kwenda kutumia nzima
byte-- hivyo zeros wote, ni labda

1177
00:57:26,800 --> 00:57:31,050
zote zile, au kitu kama hicho,
au moja tu 1 miongoni mwa bits nane.

1178
00:57:31,050 --> 00:57:34,962
>> char, wakati huo huo, kutumika kwa ajili ya tabia
kama Ascii tabia per wiki iliyopita,

1179
00:57:34,962 --> 00:57:36,170
ni kwenda kuwa tabia moja.

1180
00:57:36,170 --> 00:57:42,340
Na kwamba synchs up na wazo yetu ya
hilo kuwa hakuna zaidi ya 256 bits-- badala yake,

1181
00:57:42,340 --> 00:57:45,360
synchs na ni kuwa hakuna
zaidi ya 8 bits, ambayo

1182
00:57:45,360 --> 00:57:47,450
inatupa maadili kama wengi kama 256.

1183
00:57:47,450 --> 00:57:49,680
mara mbili ni kwenda
kuwa 8 ka au 64 bits.

1184
00:57:49,680 --> 00:57:50,510
>> kuelea ni 4.

1185
00:57:50,510 --> 00:57:51,690
int ni 4.

1186
00:57:51,690 --> 00:57:52,980
muda mrefu, kwa muda mrefu ni 8.

1187
00:57:52,980 --> 00:57:54,716
Na kamba ni 8.

1188
00:57:54,716 --> 00:57:55,840
Lakini usijali kuhusu hilo.

1189
00:57:55,840 --> 00:57:57,340
Tunakwenda peel nyuma kwamba safu.

1190
00:57:57,340 --> 00:57:59,940
Ni zinageuka, masharti Unaweza
kuwa mrefu zaidi ya 8 ka.

1191
00:57:59,940 --> 00:58:02,310
>> Na, kwa hakika, tumekuwa imeandikwa
masharti tayari, hello dunia,

1192
00:58:02,310 --> 00:58:03,700
zaidi ya 8 ka.

1193
00:58:03,700 --> 00:58:06,270
Lakini tutaweza kurudi kwa
kwamba katika muda tu.

1194
00:58:06,270 --> 00:58:09,690
Lakini kuchukua mbali hapa ni yafuatayo.

1195
00:58:09,690 --> 00:58:15,320
>> kompyuta yoyote tu ina finite
kiasi cha kumbukumbu na nafasi.

1196
00:58:15,320 --> 00:58:17,860
Unaweza tu kuhifadhi wengi
files juu ya Mac au PC yako.

1197
00:58:17,860 --> 00:58:23,030
Unaweza tu kuhifadhi mipango mingi katika
RAM mbio mara moja, lazima, hata

1198
00:58:23,030 --> 00:58:26,360
na kumbukumbu virtual, kwa sababu
una kiasi kidogo cha RAM.

1199
00:58:26,360 --> 00:58:28,990
>> Na tu picture-- kama
wewe sijawahi imefungua mbali

1200
00:58:28,990 --> 00:58:31,300
au kuamuru kumbukumbu ya ziada
kwa ajili ya kompyuta, wewe

1201
00:58:31,300 --> 00:58:33,670
wanaweza kujua kwamba
ndani ya kompyuta yako

1202
00:58:33,670 --> 00:58:36,590
ni kitu ambacho inaonekana
kidogo kama hii.

1203
00:58:36,590 --> 00:58:40,540
Hivyo hii ni tu kampuni ya kawaida aitwaye
Muhimu kwamba inafanya RAM kwa kompyuta.

1204
00:58:40,540 --> 00:58:43,620
Na RAM ni ambapo programu
kuishi wakati wao ni mbio.

1205
00:58:43,620 --> 00:58:46,630
>> Kadhalika kila Mac au PC, wakati wewe mara mbili
click mpango, na ni kufungua,

1206
00:58:46,630 --> 00:58:48,921
na kufungua baadhi neno hati
au kitu kama hicho,

1207
00:58:48,921 --> 00:58:51,764
ni maduka hayo kwa muda katika
RAM, kwa sababu RAM ni kasi

1208
00:58:51,764 --> 00:58:53,680
kuliko disk yako ngumu, au
hali yako imara disk.

1209
00:58:53,680 --> 00:58:56,600
Hivyo ni tu ambapo mipango kwenda
kuishi wakati wao ni mbio,

1210
00:58:56,600 --> 00:58:58,060
au wakati mafaili zinatumika.

1211
00:58:58,060 --> 00:59:00,890
>> Hivyo kuwa mambo ambayo kuangalia
kama ndani ya hii ya mbali yako,

1212
00:59:00,890 --> 00:59:03,320
au mambo kubwa kidogo
ndani ya desktop yako.

1213
00:59:03,320 --> 00:59:07,440
Lakini muhimu ni wewe tu na
finite idadi ya mambo haya.

1214
00:59:07,440 --> 00:59:11,230
Na kuna tu kiasi kidogo cha
vifaa wamekaa dawati hii haki

1215
00:59:11,230 --> 00:59:11,730
hapa.

1216
00:59:11,730 --> 00:59:15,920
>> Hivyo, hakika, hatuwezi kuhifadhi
kubwa kwa muda mrefu namba.

1217
00:59:15,920 --> 00:59:19,030
Na, hata hivyo, kama unadhani nyuma
daraja shule, jinsi ya tarakimu watu wengi Unaweza

1218
00:59:19,030 --> 00:59:21,400
una haki
ya uhakika decimal?

1219
00:59:21,400 --> 00:59:24,680
Kwa jambo hilo, jinsi ya tarakimu watu wengi Unaweza
una kushoto ya uhakika decimal?

1220
00:59:24,680 --> 00:59:26,300
Kweli, kubwa wengi.

1221
00:59:26,300 --> 00:59:30,840
>> Sasa, sisi binadamu anaweza tu
kujua jinsi ya kutamka milioni,

1222
00:59:30,840 --> 00:59:34,990
na bilioni, trilioni, na
quadrillion, na quintillion.

1223
00:59:34,990 --> 00:59:39,370
Na mimi nina kusukuma mipaka ya yangu
understanding-- au my-- mimi kuelewa

1224
00:59:39,370 --> 00:59:41,110
idadi, lakini yangu
matamshi ya namba.

1225
00:59:41,110 --> 00:59:44,720
Lakini wanaweza kupata kubwa na kubwa kwa
tarakimu infinitely wengi wa kushoto

1226
00:59:44,720 --> 00:59:47,050
au na haki ya uhakika decimal.

1227
00:59:47,050 --> 00:59:50,040
>> Lakini kompyuta tu kuwa
kiasi kidogo cha kumbukumbu,

1228
00:59:50,040 --> 00:59:53,510
finite idadi ya transistors, a
finite idadi ya balbu mwanga ndani.

1229
00:59:53,510 --> 00:59:57,350
Hivyo kile kinachotokea wakati
wewe kukimbia nje ya nafasi?

1230
00:59:57,350 --> 00:59:59,620
Kwa maneno mengine, kama wewe
kufikiri nyuma kwa wiki iliyopita

1231
00:59:59,620 --> 01:00:03,160
wakati sisi aliyesema kuhusu idadi
wenyewe kuwakilishwa katika binary,

1232
01:00:03,160 --> 01:00:05,480
tuseme kwamba sisi tumepewa
thamani hii 8-bit hapa.

1233
01:00:05,480 --> 01:00:08,290
>> Na tuna saba 1 na moja 0.

1234
01:00:08,290 --> 01:00:10,827
Na tuseme kwamba tunataka
kuongeza 1 kwa thamani hii.

1235
01:00:10,827 --> 01:00:12,410
Hii ni kweli kubwa hivi sasa.

1236
01:00:12,410 --> 01:00:16,610
>> Hii ni 254, kama mimi kukumbuka
math kutoka kulia wiki iliyopita.

1237
01:00:16,610 --> 01:00:19,480
Lakini nini kama mimi kubadili
kwamba rightmost 0 kwa 1?

1238
01:00:19,480 --> 01:00:22,800
Hesabu yote, ya
Bila shaka, inakuwa nane 1 ya.

1239
01:00:22,800 --> 01:00:24,050
Hivyo sisi bado ni nzuri.

1240
01:00:24,050 --> 01:00:27,204
>> Na kwamba pengine inawakilisha
255, ingawa kulingana na mazingira

1241
01:00:27,204 --> 01:00:29,120
inaweza kweli kuwakilisha
namba hasi.

1242
01:00:29,120 --> 01:00:31,240
Lakini zaidi juu ya kwamba wakati mwingine.

1243
01:00:31,240 --> 01:00:34,220
Hii anahisi kama ni kuhusu
kama juu kama mimi unaweza kuhesabu.

1244
01:00:34,220 --> 01:00:35,290
>> Sasa, ni bits 8 tu.

1245
01:00:35,290 --> 01:00:38,170
Na Mac yangu, hakika, ina njia
zaidi ya 8 bits ya kumbukumbu.

1246
01:00:38,170 --> 01:00:39,170
Lakini haina kuwa finite.

1247
01:00:39,170 --> 01:00:43,230
Hivyo hoja hiyo inatumika, hata kama sisi
kuwa na zaidi ya hawa juu ya screen.

1248
01:00:43,230 --> 01:00:47,020
>> Lakini nini kinatokea kama wewe ni
kuhifadhi idadi hiyo, 255,

1249
01:00:47,020 --> 01:00:49,290
na unataka kuhesabu 1 kidogo juu?

1250
01:00:49,290 --> 01:00:51,600
Unataka kwenda 255-256.

1251
01:00:51,600 --> 01:00:55,800
tatizo, bila shaka, ni kwamba kama wewe
kuanza kuhesabu saa sifuri kama wiki iliyopita,

1252
01:00:55,800 --> 01:00:59,670
huwezi kuhesabu kama juu
kama 256, achilia 257,

1253
01:00:59,670 --> 01:01:02,584
achilia 258, m kwa sababu kile
hutokea wakati kuongeza 1?

1254
01:01:02,584 --> 01:01:05,000
Kama wewe kufanya umri wa daraja shule
mbinu, kuweka 1 hapa,

1255
01:01:05,000 --> 01:01:08,150
na kisha 1 plus 1 ni 2, lakini hiyo ni
kweli zero, wewe kubeba 1,

1256
01:01:08,150 --> 01:01:09,695
kubeba 1, kubeba 1.

1257
01:01:09,695 --> 01:01:12,620
Mambo yote haya,
1 hayo, nenda na sifuri.

1258
01:01:12,620 --> 01:01:17,820
Na wewe upepo hadi, ndiyo, kama mtu
alidokeza, 1 upande wa kushoto.

1259
01:01:17,820 --> 01:01:22,540
Lakini kila kitu unaweza
kweli kuona na inafaa katika kumbukumbu

1260
01:01:22,540 --> 01:01:27,960
ni nane tu 0, ambayo ni kusema
wakati fulani kama wewe, kompyuta,

1261
01:01:27,960 --> 01:01:32,490
walijaribu kuhesabu juu ya kutosha juu, uko
kwenda kufungia, inaweza kuonekana,

1262
01:01:32,490 --> 01:01:35,850
na sifuri, au labda hata hasi
namba, ambayo ni hata chini ya sifuri.

1263
01:01:35,850 --> 01:01:37,260
>> Na tunaweza aina ya kuona hii.

1264
01:01:37,260 --> 01:01:39,900
Hebu kwenda mbele na kuandika
halisi haraka mpango hapa.

1265
01:01:39,900 --> 01:01:43,690
Hebu kwenda mbele na kuandika
programu inayoitwa kufurika.

1266
01:01:43,690 --> 01:01:49,980
Pamoja na CS50.h, ni pamoja na
kiwango cha IO.h-- loo,

1267
01:01:49,980 --> 01:01:51,730
Mimi kwa kweli amekosa syntax yangu mwangaza.

1268
01:01:51,730 --> 01:01:54,440
Basi hebu kuokoa hii kama overflow.c.

1269
01:01:54,440 --> 01:01:57,084
>> Na sasa int kuu void--
na baada ya muda, tutaweza

1270
01:01:57,084 --> 01:01:59,500
kurudi kueleza kwa nini
sisi kuendelea kuandika int kuu utupu.

1271
01:01:59,500 --> 01:02:02,080
Lakini kwa sasa, hebu tu kufanya
hivyo, kuchukua ni kwa nafasi.

1272
01:02:02,080 --> 01:02:06,200
Hebu kutoa mwenyewe int,
na initialize kwa 0.

1273
01:02:06,200 --> 01:02:11,716
>> Hebu basi kufanya kwa int i kupata zero--
kweli, hebu kufanya usio kitanzi

1274
01:02:11,716 --> 01:02:12,590
na kuona nini kinatokea.

1275
01:02:12,590 --> 01:02:22,440
Wakati kweli, basi hebu magazeti nje n
ni asilimia i, backslash n, kuziba-katika n.

1276
01:02:22,440 --> 01:02:27,200
Lakini, sasa, hebu kufanya n anapata n plus 1.

1277
01:02:27,200 --> 01:02:29,660
>> Hivyo kwa maneno mengine, juu ya kila
iteration ya kitanzi hii usio na mipaka,

1278
01:02:29,660 --> 01:02:32,550
hebu kuchukua thamani n ya,
na kuongeza 1 kwa hilo, na kisha

1279
01:02:32,550 --> 01:02:34,350
kuhifadhi matokeo ya nyuma katika n upande wa kushoto.

1280
01:02:34,350 --> 01:02:37,150
Na, kwa kweli, tumeona syntax
kidogo kama hii, kwa ufupi.

1281
01:02:37,150 --> 01:02:39,730
hila baridi ni badala
ya kuandika yote haya nje,

1282
01:02:39,730 --> 01:02:42,770
unaweza kweli kusema n plus sawa na 1.

1283
01:02:42,770 --> 01:02:47,480
>> Au kama wewe kweli unataka kuwa dhana tu,
unaweza kusema n plus plus nusu koloni.

1284
01:02:47,480 --> 01:02:50,130
Lakini hizi mbili za mwisho ni tu
nini tunatarajia kuwaita kisintaksia sukari

1285
01:02:50,130 --> 01:02:50,790
kwa jambo la kwanza.

1286
01:02:50,790 --> 01:02:53,456
>> Jambo la kwanza ni wazi zaidi,
kabisa faini, sahihi kabisa.

1287
01:02:53,456 --> 01:02:55,470
Lakini hii ni zaidi ya kawaida, mimi itabidi kusema.

1288
01:02:55,470 --> 01:02:57,210
Hivyo tutaweza kufanya hivyo kwa muda tu.

1289
01:02:57,210 --> 01:03:01,685
>> Hebu sasa kufanya kufurika, ambayo sauti
badala ominous, dot kufyeka kufurika.

1290
01:03:01,685 --> 01:03:04,380

1291
01:03:04,380 --> 01:03:09,852
Hebu angalia, n ni kupata pretty kubwa.

1292
01:03:09,852 --> 01:03:11,310
Lakini hebu fikiria, jinsi kubwa unaweza n kupata?

1293
01:03:11,310 --> 01:03:12,870
>> n ni int.

1294
01:03:12,870 --> 01:03:16,400
Tuliona wakati iliyopita na ukubwa wa
mfano kwamba int ni ka nne.

1295
01:03:16,400 --> 01:03:22,070
Tunajua kutokana na wiki iliyopita, ka nne ni
32 bits, kwa sababu 8 mara 4, hiyo ni 32.

1296
01:03:22,070 --> 01:03:23,460
Hiyo inaenda kuwa bilioni 4.

1297
01:03:23,460 --> 01:03:25,802
>> Na sisi ni hadi 800,000.

1298
01:03:25,802 --> 01:03:28,510
Hii ni kwenda kuchukua milele
kuhesabu kama juu kama mimi waweza.

1299
01:03:28,510 --> 01:03:30,635
Hivyo mimi nina kwenda mbele,
kama waweza kabla ya muda mrefu,

1300
01:03:30,635 --> 01:03:34,910
na kugonga Control C-- kusema ukweli, Control
C, mengi, ambapo Control C kwa ujumla

1301
01:03:34,910 --> 01:03:36,034
njia kufuta.

1302
01:03:36,034 --> 01:03:38,200
Kwa bahati mbaya, kwa sababu hii
ni mbio katika wingu,

1303
01:03:38,200 --> 01:03:41,190
pengine lile wingu ni
kutema mate nje mambo mengi,

1304
01:03:41,190 --> 01:03:44,180
pato sana, ni kwenda
kuchukua muda kidogo kwa ajili ya pembejeo yangu

1305
01:03:44,180 --> 01:03:45,630
kupata wingu.

1306
01:03:45,630 --> 01:03:49,240
Hivyo hata kama mimi hit
Control C sekunde chache zilizopita,

1307
01:03:49,240 --> 01:03:53,110
hii ni dhahiri upande
athari ya kitanzi usio.

1308
01:03:53,110 --> 01:03:56,070
>> Na hivyo katika kesi hiyo, tuko
ataondoka kwamba kuwa.

1309
01:03:56,070 --> 01:03:59,050
Na tunakwenda kuongeza mwingine
terminal dirisha juu hapa

1310
01:03:59,050 --> 01:04:03,186
kwa pamoja, ambayo bila shaka haina
kama kwamba, tangu ni bado kufikiri.

1311
01:04:03,186 --> 01:04:05,310
Na hebu kwenda mbele na kuwa
kidogo zaidi ya busara.

1312
01:04:05,310 --> 01:04:07,768
>> Mimi nina kwenda mbele na kufanya
hii tu finitely wengi nyakati.

1313
01:04:07,768 --> 01:04:10,047
Hebu kutumia kwa kitanzi,
ambayo mimi alluded mapema.

1314
01:04:10,047 --> 01:04:10,630
Hebu kufanya hivyo.

1315
01:04:10,630 --> 01:04:13,430
Nipe mwingine int variable i anapata 0.

1316
01:04:13,430 --> 01:04:17,430
i ni chini ya, hebu sema, 64 i ++.

1317
01:04:17,430 --> 01:04:24,010
Na sasa napenda kwenda mbele na magazeti
nje n ni asilimia i, comma n.

1318
01:04:24,010 --> 01:04:27,547
Na kisha n-- hii bado
kwenda kuchukua milele.

1319
01:04:27,547 --> 01:04:28,130
Hebu kufanya hivyo.

1320
01:04:28,130 --> 01:04:30,620
>> n anapata n mara 2.

1321
01:04:30,620 --> 01:04:34,140
Au tunaweza kuwa na dhana
na kufanya mara sawa na 2.

1322
01:04:34,140 --> 01:04:37,120
Lakini hebu tu kusema n
sawa na yenyewe, mara 2.

1323
01:04:37,120 --> 01:04:39,321
Kwa maneno mengine, katika hili
mpya toleo la mpango,

1324
01:04:39,321 --> 01:04:41,820
Sitaki kusubiri daima
kutoka kama 800,000 kwa bilioni 4.

1325
01:04:41,820 --> 01:04:43,070
Hebu tu kupata zaidi ya hii na.

1326
01:04:43,070 --> 01:04:44,920
>> Hebu kweli mara mbili n kila wakati.

1327
01:04:44,920 --> 01:04:47,660
Ambayo, kukumbuka, mara dufu ni
kinyume cha kuwa, bila shaka.

1328
01:04:47,660 --> 01:04:50,035
Na ambapo wiki iliyopita tuna
kitu tena, na tena,

1329
01:04:50,035 --> 01:04:52,200
na tena, super haraka,
mara dufu bila ya shaka

1330
01:04:52,200 --> 01:04:58,080
kupata yetu kutoka 1 kwa kubwa iwezekanavyo
thamani kwamba tunaweza kuhesabu kwa pamoja int.

1331
01:04:58,080 --> 01:04:59,750
>> Basi hebu kufanya hasa hili.

1332
01:04:59,750 --> 01:05:01,720
Na tutaweza kurudi huu kabla ya muda mrefu.

1333
01:05:01,720 --> 01:05:04,180
Lakini hii, tena, ni tu kama
kuzuia kurudia katika Scratch.

1334
01:05:04,180 --> 01:05:05,600
Na wewe utakuwa kutumia hii kabla ya muda mrefu.

1335
01:05:05,600 --> 01:05:10,170
>> Hii ina maana kuhesabu kutoka sifuri
hadi, lakini si sawa, hadi 64.

1336
01:05:10,170 --> 01:05:14,285
Na juu ya kila iteration ya hii
kitanzi, tu kuweka incrementing i.

1337
01:05:14,285 --> 01:05:18,990
Hivyo i ++ - na hii kujenga ujumla
kwenye mstari 7 ni njia tu super kawaida

1338
01:05:18,990 --> 01:05:22,290
ya kurudia baadhi ya mistari ya
kanuni, baadhi idadi ya nyakati.

1339
01:05:22,290 --> 01:05:23,362
Ambayo mstari wa kanuni?

1340
01:05:23,362 --> 01:05:25,570
Hizi braces curly, kama wewe
huenda zilizopatikana kutoka sasa,

1341
01:05:25,570 --> 01:05:26,780
maana, kufanya yafuatayo.

1342
01:05:26,780 --> 01:05:29,510
>> Ni katika kama Scratch, wakati
ina vitalu njano

1343
01:05:29,510 --> 01:05:32,680
na rangi nyingine aina hiyo ya
kukumbatia au kumkumbatia vitalu nyingine.

1344
01:05:32,680 --> 01:05:34,750
Hiyo ni nini curly wale
braces ni kufanya hapa.

1345
01:05:34,750 --> 01:05:40,200
Hivyo kama mimi got syntax yangu right-- wewe
unaweza kuona ishara karoti katika C njia

1346
01:05:40,200 --> 01:05:42,706
hiyo ni mara ngapi mimi nilikuwa
kujaribu kutatua tatizo hili.

1347
01:05:42,706 --> 01:05:45,330
Hivyo hebu kujikwamua kwamba moja
kabisa, na karibu kwamba dirisha.

1348
01:05:45,330 --> 01:05:46,520
Na tutaweza kutumia mwezi mmoja.

1349
01:05:46,520 --> 01:05:51,980
Kufanya kufurika, dot kufyeka
kufurika, Ingieni, wote haki,

1350
01:05:51,980 --> 01:05:53,090
inaonekana mbaya wakati wa kwanza.

1351
01:05:53,090 --> 01:05:56,200
Lakini hebu kitabu nyuma katika wakati,
kwa sababu mimi hii mara 64.

1352
01:05:56,200 --> 01:05:58,700
>> Na taarifa mara ya kwanza, n ni 1.

1353
01:05:58,700 --> 01:06:03,110
mara ya pili, n ni 2,
kisha 4, kisha 8, kisha 16.

1354
01:06:03,110 --> 01:06:09,450
Na inaonekana kwamba haraka kama
Mimi kupata takribani bilioni 1,

1355
01:06:09,450 --> 01:06:12,800
kama mimi mara mbili yake tena, kwamba
anipe bilioni 2.

1356
01:06:12,800 --> 01:06:14,980
Lakini zinageuka, ni
haki juu ya cusp.

1357
01:06:14,980 --> 01:06:18,930
>> Na hivyo ni kweli kufurika
int kutoka bilioni 1

1358
01:06:18,930 --> 01:06:23,514
kwa takribani hasi 2
bilioni, kwa sababu integer,

1359
01:06:23,514 --> 01:06:25,430
tofauti na idadi sisi
walikuwa kuchukua wiki iliyopita,

1360
01:06:25,430 --> 01:06:28,397
inaweza kuwa wote chanya na hasi
katika hali halisi na katika kompyuta.

1361
01:06:28,397 --> 01:06:30,730
Na ili angalau mmoja wa wale
bits ni ufanisi kuibiwa.

1362
01:06:30,730 --> 01:06:34,190
Hivyo kweli sisi tu kuwa 31 bits,
au bilioni 2 maadili iwezekanavyo.

1363
01:06:34,190 --> 01:06:38,220
>> Lakini kwa sasa, takeaway ni kabisa
tu, chochote nambari hizi ni

1364
01:06:38,220 --> 01:06:42,280
na chochote math ni,
kitu mbaya hutokea hatimaye,

1365
01:06:42,280 --> 01:06:46,980
kwa sababu hatimaye wewe ni kujaribu
permute bits moja mara nyingi sana.

1366
01:06:46,980 --> 01:06:51,060
Na wewe kwa ufanisi kwenda kutoka
1 kwa labda wote 0, au labda

1367
01:06:51,060 --> 01:06:54,260
baadhi tu mfano mwingine kwamba
wazi, kulingana na mazingira,

1368
01:06:54,260 --> 01:06:56,342
inaweza kutafsiriwa kama namba hasi.

1369
01:06:56,342 --> 01:06:59,300
Na hivyo inaweza kuonekana mimi juu
Unaweza kuhesabu katika mpango huu hasa

1370
01:06:59,300 --> 01:07:01,210
ni tu takribani bilioni 1.

1371
01:07:01,210 --> 01:07:02,760
Lakini kuna ufumbuzi ubaguzi hapa.

1372
01:07:02,760 --> 01:07:03,480
Unajua nini?

1373
01:07:03,480 --> 01:07:07,600
>> Napenda kubadili kutoka
int kwa muda mrefu kwa muda mrefu.

1374
01:07:07,600 --> 01:07:10,633
Na napenda kwenda mbele hapa
na say-- mimi nina kwenda kuwa

1375
01:07:10,633 --> 01:07:12,290
kubadili hali hii kwa unsigned muda mrefu.

1376
01:07:12,290 --> 01:07:16,860
Au, hebu angalia, mimi kamwe kukumbuka mwenyewe.

1377
01:07:16,860 --> 01:07:19,920
>> Hebu kwenda mbele na kufanya kufurika.

1378
01:07:19,920 --> 01:07:21,860
Hakuna, si kwamba ni, LLD, asante.

1379
01:07:21,860 --> 01:07:23,430
Hivyo wakati mwingine Clang inaweza kuwa na manufaa.

1380
01:07:23,430 --> 01:07:27,550
Sikuwa kukumbuka nini format
specifier alikuwa kwa muda mrefu kwa muda mrefu.

1381
01:07:27,550 --> 01:07:28,950
>> Lakini, kwa kweli, Clang aliniambia.

1382
01:07:28,950 --> 01:07:31,570
Green ni aina fulani ya mema,
bado ina maana alifanya makosa.

1383
01:07:31,570 --> 01:07:33,190
Ni kubahatisha kwamba mimi maana LLD.

1384
01:07:33,190 --> 01:07:38,750
>> Hivyo basi mimi kuchukua ni ushauri, kwa muda mrefu
muda mrefu idadi decimal, ila hiyo.

1385
01:07:38,750 --> 01:07:43,190
Na napenda rerun yake, dot
kufyeka kufurika, kuingia.

1386
01:07:43,190 --> 01:07:45,020
Na sasa nini baridi ni hii.

1387
01:07:45,020 --> 01:07:49,140
>> Kama mimi kitabu nyuma katika wakati, bado tunaanza
kuhesabu katika place-- huo 1, 2, 4,

1388
01:07:49,140 --> 01:07:50,220
8, 16.

1389
01:07:50,220 --> 01:07:54,860
Ilani, sisi kupata yote
njia hadi bilioni 1.

1390
01:07:54,860 --> 01:07:57,070
Lakini basi sisi salama kupata bilioni 2.

1391
01:07:57,070 --> 01:08:01,300
>> Kisha sisi kupata bilioni 4,
kisha bilioni 8, bilioni 17.

1392
01:08:01,300 --> 01:08:03,340
Na sisi kwenda juu, na
juu, na ya juu.

1393
01:08:03,340 --> 01:08:05,740
Hatimaye, hii, pia, mapumziko.

1394
01:08:05,740 --> 01:08:09,350
>> Hatimaye, kwa muda mrefu kwa muda mrefu,
ambayo ni thamani ya 64-bit, si

1395
01:08:09,350 --> 01:08:13,660
thamani 32-bit, kama hesabu
juu sana, kufungia 0.

1396
01:08:13,660 --> 01:08:16,410
Na katika kesi hii, sisi kutokea kwa
kuishia na namba hasi.

1397
01:08:16,410 --> 01:08:17,550
>> Hivyo hii ni tatizo.

1398
01:08:17,550 --> 01:08:20,439
Na zinageuka kuwa hii
Tatizo siyo arcane kwamba wote.

1399
01:08:20,439 --> 01:08:23,060
Japokuwa nimekuwa makusudi
ikiwa ni pamoja na makosa hayo,

1400
01:08:23,060 --> 01:08:26,149
ni zamu nje tunaona aina ya yote
inayotuzunguka, au angalau baadhi yetu kufanya.

1401
01:08:26,149 --> 01:08:28,939
>> Hivyo katika Lego Star Wars, kama
umefanya milele kucheza mchezo,

1402
01:08:28,939 --> 01:08:33,830
ni zamu nje unaweza kwenda karibu
kuvunja vitu juu katika LEGO dunia,

1403
01:08:33,830 --> 01:08:36,640
na kukusanya sarafu, kimsingi.

1404
01:08:36,640 --> 01:08:39,200
Na kama wameweza milele kucheza
mchezo huu njia muda sana,

1405
01:08:39,200 --> 01:08:42,630
kama mtu binafsi hii unnamed
hapa alivyofanya, idadi ya jumla

1406
01:08:42,630 --> 01:08:46,700
ya sarafu kwamba unaweza kukusanya
ni, inaweza kuonekana, bilioni 4.

1407
01:08:46,700 --> 01:08:48,240
>> Sasa, pamoja na ni kweli mviringo.

1408
01:08:48,240 --> 01:08:50,239
Hivyo LEGO alikuwa anajaribu
kuweka mambo user kirafiki.

1409
01:08:50,239 --> 01:08:53,779
Wao hawakuwa kufanya hivyo hasa 2 kwa
32 nguvu, per wiki iliyopita.

1410
01:08:53,779 --> 01:08:55,310
Lakini bilioni 4 ni sababu.

1411
01:08:55,310 --> 01:08:58,979
Inaonekana, kulingana na habari hii,
kwamba LEGO, na kampuni hiyo

1412
01:08:58,979 --> 01:09:02,624
alifanya programu hii halisi, aliamua
kwamba upeo wa idadi ya sarafu

1413
01:09:02,624 --> 01:09:04,540
user unaweza kukusanya
ni kweli, bilioni 4,

1414
01:09:04,540 --> 01:09:12,069
kwa sababu waliowachagua katika kanuni zao
kutumia si muda mrefu kwa muda mrefu, inaonekana,

1415
01:09:12,069 --> 01:09:16,140
lakini tu integer, unsigned
integer, tu integer chanya, ambaye

1416
01:09:16,140 --> 01:09:18,089
max thamani ya kitu takribani hiyo.

1417
01:09:18,089 --> 01:09:19,380
Naam, hapa ni mwingine mmoja funny.

1418
01:09:19,380 --> 01:09:23,500
Hivyo katika mchezo Civilization, ambayo
baadhi yenu wanaweza kuwa na mazoea, na

1419
01:09:23,500 --> 01:09:26,660
zinageuka kuwa miaka iliyopita kulikuwa
Ilikuwa mdudu katika mchezo huu ambapo

1420
01:09:26,660 --> 01:09:28,750
kama wewe jukumu
ya Gandhi katika mchezo,

1421
01:09:28,750 --> 01:09:34,020
badala ya yeye kuwa pacifist sana,
badala alikuwa incredibly, incredibly

1422
01:09:34,020 --> 01:09:36,399
fujo, katika hali fulani.

1423
01:09:36,399 --> 01:09:40,529
Hasa, kwa njia hiyo Civilization
kazi ni kwamba kama wewe, mchezaji,

1424
01:09:40,529 --> 01:09:44,680
kupitisha demokrasia, yako
alama uchokozi anapata

1425
01:09:44,680 --> 01:09:48,130
decremented wawili, kwa hiyo minus
bala, na kisha minus minus.

1426
01:09:48,130 --> 01:09:50,569
>> Hivyo wewe Ondoa 2 kutoka
halisi iterating yako.

1427
01:09:50,569 --> 01:09:56,650
Kwa bahati mbaya, kama iterating yako ni
awali 1, na wewe Ondoa 2 kutoka humo

1428
01:09:56,650 --> 01:09:59,050
baada ya kupitisha demokrasia
kama Gandhi hapa wapate

1429
01:09:59,050 --> 01:10:02,200
wamefanya, kwa sababu alikuwa passive-- sana
1 juu ya ukubwa wa uchokozi.

1430
01:10:02,200 --> 01:10:04,830
Lakini kama yeye antar demokrasia, basi
aendako kutoka 1 kwa hasi 1.

1431
01:10:04,830 --> 01:10:11,470
>> Kwa bahati mbaya, walikuwa
kutumia namba unsigned,

1432
01:10:11,470 --> 01:10:15,400
ambayo ina maana wao kutibiwa hata hasi
idadi kana kwamba yalikuwa mazuri.

1433
01:10:15,400 --> 01:10:19,780
Na zinageuka kuwa
chanya sawa na hasi 1,

1434
01:10:19,780 --> 01:10:23,480
katika mipango ya kawaida ya kompyuta, ni 255.

1435
01:10:23,480 --> 01:10:27,250
Hivyo kama Gandhi antar
demokrasia, na kwa hiyo ina

1436
01:10:27,250 --> 01:10:32,470
uchokozi wake alama ilipungua,
ni kweli Rolls kote kwa 255

1437
01:10:32,470 --> 01:10:35,470
na hufanya yake zaidi
tabia ya fujo katika mchezo.

1438
01:10:35,470 --> 01:10:36,930
Hivyo unaweza Google juu ya hili.

1439
01:10:36,930 --> 01:10:39,380
Na ilikuwa, kwa kweli,
ajali programu mdudu,

1440
01:10:39,380 --> 01:10:43,010
lakini hiyo ni aliingia kabisa
lore tangu wakati huo.

1441
01:10:43,010 --> 01:10:44,360
>> Hayo ni yote na furaha na cute.

1442
01:10:44,360 --> 01:10:47,760
Zaidi ya kutisha ni wakati halisi
vifaa ulimwengu wa kweli, na si michezo,

1443
01:10:47,760 --> 01:10:48,820
kuwa na mende hayo.

1444
01:10:48,820 --> 01:10:54,500
Kwa kweli, tu mwaka mmoja uliopita makala alikuja
nje kuhusu Boeing 787 Dreamliner.

1445
01:10:54,500 --> 01:10:56,850
>> Na makala mwanzoni
mtazamo wasomaji arcane kidogo.

1446
01:10:56,850 --> 01:11:01,480
Lakini kusema hayo, programu
mazingira magumu katika Boeing

1447
01:11:01,480 --> 01:11:04,790
mpya 787 Dreamliner ndege ina
uwezo wa kusababisha marubani

1448
01:11:04,790 --> 01:11:07,220
kupoteza udhibiti wa
ndege, pengine

1449
01:11:07,220 --> 01:11:11,750
katika katikati ya ndege, maafisa FAA
alionya mashirika ya ndege hivi karibuni.

1450
01:11:11,750 --> 01:11:14,520
Ilikuwa ni uamuzi
kwamba mtindo 787

1451
01:11:14,520 --> 01:11:19,770
ndege ambayo imekuwa powered
siku kuendelea kwa 248

1452
01:11:19,770 --> 01:11:24,880
unaweza kupoteza wote alternating sasa, AC,
nguvu za umeme kutokana na jenereta

1453
01:11:24,880 --> 01:11:28,892
vitengo vya kudhibiti, GCUs, wakati huo huo
kwenda katika kushindwa hali ya salama.

1454
01:11:28,892 --> 01:11:29,850
Ni aina ya kupoteza yangu.

1455
01:11:29,850 --> 01:11:35,390
Lakini memo alisema, OK, sasa mimi got kwamba,
hali ilisababishwa na programu

1456
01:11:35,390 --> 01:11:38,590
kukabiliana ndani ya
kudhibiti jenereta

1457
01:11:38,590 --> 01:11:44,860
vitengo kwamba ufurikishe baada
siku 248 ya nguvu ya kuendelea.

1458
01:11:44,860 --> 01:11:47,070
Sisi ni kutoa hii
taarifa ili kuzuia hasara

1459
01:11:47,070 --> 01:11:49,300
ya yote AC umeme
nguvu, ambayo inaweza kusababisha

1460
01:11:49,300 --> 01:11:50,980
hasara ya udhibiti wa ndege.

1461
01:11:50,980 --> 01:11:55,380
>> Hivyo, literally, kuna baadhi ya integer,
au baadhi sawa data aina,

1462
01:11:55,380 --> 01:11:57,960
kuwa kutumika katika programu
katika ndege halisi

1463
01:11:57,960 --> 01:12:00,756
kwamba kama wewe kuweka ndege yako
juu ya muda wa kutosha, ambayo inaonekana

1464
01:12:00,756 --> 01:12:03,880
inaweza kuwa kesi kama wewe ni mbio tu
yao mara kwa mara na kamwe unplugging

1465
01:12:03,880 --> 01:12:06,810
ndege yako, inaonekana, au
kuruhusu betri wake kufa,

1466
01:12:06,810 --> 01:12:09,840
hatimaye kuhesabu juu, na juu,
na juu, na juu, na juu, na up.

1467
01:12:09,840 --> 01:12:12,150
>> Na, kwa asili, a
kiasi kidogo cha kumbukumbu

1468
01:12:12,150 --> 01:12:15,880
ufurikishe, akalivingirisha kwa
zero au baadhi thamani hasi,

1469
01:12:15,880 --> 01:12:19,920
athari upande wa ambayo ni
ukweli frighteningly halisi

1470
01:12:19,920 --> 01:12:23,970
kwamba ndege ili haja
kuwa rebooted, kwa ufanisi,

1471
01:12:23,970 --> 01:12:27,290
au inaweza kuanguka, mbaya, kama inzi.

1472
01:12:27,290 --> 01:12:29,230
Basi hizi aina ya masuala
bado na sisi,

1473
01:12:29,230 --> 01:12:33,130
even-- hii ilikuwa makala 2015,
wote zaidi ya kutisha

1474
01:12:33,130 --> 01:12:36,100
wakati wa kufanya si lazima
kuelewa, kuthamini, au wanatarajia

1475
01:12:36,100 --> 01:12:38,640
aina wale wa makosa.

1476
01:12:38,640 --> 01:12:42,030
>> Hivyo ni zamu nje kuna mtu mwingine
jambo baya kuhusu data uwakilishi.

1477
01:12:42,030 --> 01:12:47,080
Ni zinageuka kuwa hata ikifungwa ni
aina ya kiujanja, kwa sababu ikifungwa, pia,

1478
01:12:47,080 --> 01:12:51,440
Mimi mapendekezo ni 32 bits, au
labda 64 kama wewe kutumia mara mbili.

1479
01:12:51,440 --> 01:12:53,070
Lakini hiyo ni bado zina mwisho.

1480
01:12:53,070 --> 01:12:57,070
>> Na samaki ni kwamba kama unaweza
kuweka idadi ya usio wa idadi

1481
01:12:57,070 --> 01:12:59,460
baada ya uhakika decimal,
hakuna njia wewe

1482
01:12:59,460 --> 01:13:02,690
wanaweza kuwakilisha iwezekanavyo zote
idadi ambayo tulikuwa kufundishwa

1483
01:13:02,690 --> 01:13:04,990
katika daraja shule inaweza kuwepo katika dunia.

1484
01:13:04,990 --> 01:13:08,870
kompyuta, kimsingi, ana
kuchagua subset ya idadi ya wale

1485
01:13:08,870 --> 01:13:10,200
kuiwakilisha kwa usahihi.

1486
01:13:10,200 --> 01:13:12,450
>> Sasa, kompyuta Unaweza
pande zote labda kidogo kidogo,

1487
01:13:12,450 --> 01:13:17,900
na inaweza kuruhusu takribani duka
idadi yoyote unaweza uwezekano unataka.

1488
01:13:17,900 --> 01:13:20,940
Lakini tu intuitively, kama wewe
kuwa finite idadi ya bits,

1489
01:13:20,940 --> 01:13:24,560
unaweza tu permute yao
kwa njia nyingi zina mwisho.

1490
01:13:24,560 --> 01:13:26,570
Hivyo unaweza si uwezekano
kutumia idadi finite

1491
01:13:26,570 --> 01:13:29,880
ya permutation ya bits,
chati ya zeros na ndio,

1492
01:13:29,880 --> 01:13:32,940
kuiwakilisha usio
idadi ya namba,

1493
01:13:32,940 --> 01:13:37,370
ambayo inaonyesha kwamba kompyuta nguvu
vizuri sana kuwa uongo kwetu wakati mwingine.

1494
01:13:37,370 --> 01:13:38,770
>> Kwa kweli, hebu kufanya hili.

1495
01:13:38,770 --> 01:13:41,239
Hebu kwenda nyuma katika CS50 IDE.

1496
01:13:41,239 --> 01:13:43,030
Hebu kwenda mbele na
kujenga mpango kidogo

1497
01:13:43,030 --> 01:13:47,940
aitwaye kutokuwa sahihi, ili kuonyesha kwamba
kompyuta ni kweli, imprecise.

1498
01:13:47,940 --> 01:13:51,910
>> Na napenda kwenda mbele na kuanza na
baadhi ya kificho kwamba mbele,

1499
01:13:51,910 --> 01:13:53,830
na sasa tu kufanya yafuatayo.

1500
01:13:53,830 --> 01:14:03,640
Hebu kwenda mbele na kufanya printf, asilimia
f, backslash n, 1 kugawanywa na 10.

1501
01:14:03,640 --> 01:14:07,430
Kwa maneno mengine, hebu tuzame katika zaidi
kwa 1/10, kama 1 na kugawanywa na 10.

1502
01:14:07,430 --> 01:14:09,760
Hakika, kompyuta inaweza kuwakilisha 1/10.

1503
01:14:09,760 --> 01:14:13,620
>> Basi hebu kwenda mbele na kufanya kutokuwa sahihi.

1504
01:14:13,620 --> 01:14:14,390
Hebu tuone.

1505
01:14:14,390 --> 01:14:16,210
Format bayana aina mbili.

1506
01:14:16,210 --> 01:14:18,160
Lakini hoja ina aina int.

1507
01:14:18,160 --> 01:14:19,040
Ni nini kinaendelea?

1508
01:14:19,040 --> 01:14:21,970
>> Oh, kuvutia, hivyo ni
somo la kujifunza kutoka kabla.

1509
01:14:21,970 --> 01:14:26,050
Mimi kusema, hey, kompyuta show
me kuelea na asilimia f.

1510
01:14:26,050 --> 01:14:28,200
Lakini mimi nina kutoa ni 2 ints.

1511
01:14:28,200 --> 01:14:31,120
Hivyo ni zamu nje, siwezi kurekebisha
hii katika michache ya njia.

1512
01:14:31,120 --> 01:14:38,430
>> Mimi nilikuwa tu kugeuka moja katika 1.0, na
10 katika 10.0, ambayo ingekuwa, kwa hakika,

1513
01:14:38,430 --> 01:14:42,390
kuwa na athari ya kuwabadili
yao katika floats-- bado hopefully

1514
01:14:42,390 --> 01:14:43,180
idadi sawa.

1515
01:14:43,180 --> 01:14:45,880
Au ni zamu huko nje ni kitu
tutaweza kuona tena kabla ya muda mrefu.

1516
01:14:45,880 --> 01:14:47,170
Unaweza kutupwa idadi.

1517
01:14:47,170 --> 01:14:49,880
>> Unaweza, kwa kutumia mabano huu
kujieleza, unaweza kusema,

1518
01:14:49,880 --> 01:14:52,560
hey, kompyuta, kuchukua hii
10, ambayo najua ni int.

1519
01:14:52,560 --> 01:14:54,660
Lakini kutibu hayo, tafadhali,
kana kwamba ni kuelea.

1520
01:14:54,660 --> 01:14:56,680
Lakini hii anahisi usiokuwa tata.

1521
01:14:56,680 --> 01:14:59,040
>> Kwa madhumuni yetu leo,
hebu tu literally

1522
01:14:59,040 --> 01:15:02,700
kufanya nao yaliyo maadili uhakika
na uhakika decimal, kama hii.

1523
01:15:02,700 --> 01:15:07,060
Hebu kwenda mbele na rerun, kufanya
kutokuwa sahihi, nzuri, dot kufyeka

1524
01:15:07,060 --> 01:15:08,870
imprecision, kuingia.

1525
01:15:08,870 --> 01:15:10,990
OK, sisi ni kuangalia nzuri.

1526
01:15:10,990 --> 01:15:18,194
>> 1 kugawanywa na 10, kwa mujibu wa yangu
Mac hapa, ni kweli, 0.100000.

1527
01:15:18,194 --> 01:15:21,360
Sasa, nilikuwa kufundishwa katika shule ya daraja huko
lazima idadi ya usio wa 0 ya.

1528
01:15:21,360 --> 01:15:23,151
Basi hebu angalau kujaribu
kuona baadhi ya wale.

1529
01:15:23,151 --> 01:15:26,770
Ni zinageuka kuwa printf ni kidogo
bado fancier kuliko tumekuwa kutumia.

1530
01:15:26,770 --> 01:15:30,890
Ni zinageuka huna bayana
asilimia f, au asilimia tu i.

1531
01:15:30,890 --> 01:15:33,830
Unaweza kweli bayana
baadhi ya chaguzi kudhibiti hapa.

1532
01:15:33,830 --> 01:15:36,470
>> Hasa, mimi nina kwenda
kusema, hey, printf,

1533
01:15:36,470 --> 01:15:39,660
kweli kuonyesha me 10 pointi decimal.

1534
01:15:39,660 --> 01:15:40,820
Hivyo inaonekana weird kidogo.

1535
01:15:40,820 --> 01:15:42,845
Lakini unasema asilimia,
dot, idadi ngapi

1536
01:15:42,845 --> 01:15:44,970
unataka kuona baada
uhakika decimal, na kisha f

1537
01:15:44,970 --> 01:15:48,340
kwa ajili ya gorofa, tu kwa sababu hiyo ni
nini nyaraka anasema.

1538
01:15:48,340 --> 01:15:50,080
Hebu kwenda mbele na kuokoa hiyo.

1539
01:15:50,080 --> 01:15:52,460
>> Na taarifa mno, mimi nina kupata
uchovu wa retyping mambo.

1540
01:15:52,460 --> 01:15:55,900
Hivyo mimi nina kuweka tu juu na
chini arrow funguo yangu hapa.

1541
01:15:55,900 --> 01:15:58,710
Na kama mimi kuendelea kupiga up, wewe
unaweza kuona yote ya amri

1542
01:15:58,710 --> 01:16:01,090
kwamba mimi alifanya, au kimakosa alifanya.

1543
01:16:01,090 --> 01:16:04,630
>> Na mimi nina kwenda mbele sasa na
si kweli kutumia kwamba, inaonekana.

1544
01:16:04,630 --> 01:16:11,416
Kufanya imprecision, dot
kufyeka imprecision-- hivyo

1545
01:16:11,416 --> 01:16:13,290
nini nilikuwa kufundishwa katika
daraja shule hundi nje.

1546
01:16:13,290 --> 01:16:19,010
Hata kama mimi magazeti hayo kwa 10 decimal
sehemu yake, kwa kweli, ni 0.10000.

1547
01:16:19,010 --> 01:16:19,840
Lakini unajua nini?

1548
01:16:19,840 --> 01:16:21,150
>> Hebu kupata kidogo tamaa.

1549
01:16:21,150 --> 01:16:23,990
Hebu kusema, kama, nionyeshe 55
inaelekeza baada ya decimal.

1550
01:16:23,990 --> 01:16:26,160
Hebu kweli kuchukua hii
mpango nje kwa ajili ya spin.

1551
01:16:26,160 --> 01:16:31,170
Napenda remake na kufanya
imprecision, dot kufyeka, kutokuwa sahihi.

1552
01:16:31,170 --> 01:16:32,390
>> Na hapa sisi kwenda.

1553
01:16:32,390 --> 01:16:34,420
utoto wako ilikuwa ni uongo.

1554
01:16:34,420 --> 01:16:48,410
Inavyoonekana, 1 kugawanywa na 10 ni kweli
0.100000000000000005551115123--

1555
01:16:48,410 --> 01:16:49,740
>> Ni nini kinachoendelea?

1556
01:16:49,740 --> 01:16:53,360
Naam, ni zamu nje, kama wewe aina ya
kuangalia mbali kutosha nje katika msingi

1557
01:16:53,360 --> 01:16:55,950
uwakilishi wa hii
idadi, ni kweli

1558
01:16:55,950 --> 01:17:00,400
si hasa 1/10, au 0.1 na
usio idadi ya zeros.

1559
01:17:00,400 --> 01:17:01,630
Sasa, kwa nini ni kwamba?

1560
01:17:01,630 --> 01:17:06,250
>> Naam, hata ingawa hii ni rahisi
idadi ya sisi wanadamu, 1 kugawanywa na 10,

1561
01:17:06,250 --> 01:17:10,910
bado ni moja ya kubwa wengi
idadi ambayo sisi inaweza kufikiria juu.

1562
01:17:10,910 --> 01:17:14,490
Lakini kompyuta inaweza tu kuwakilisha
finitely wengi hivyo idadi.

1563
01:17:14,490 --> 01:17:18,710
Na hivyo, kwa ufanisi, nini
kompyuta ni kuonyesha sisi ni karibu wake

1564
01:17:18,710 --> 01:17:22,940
makadirio ya idadi
tunataka kuamini ni 1/10,

1565
01:17:22,940 --> 01:17:27,760
au kweli 0.10000 hauna mwisho.

1566
01:17:27,760 --> 01:17:30,425
>> Badala yake, ingawa, hii ni
karibu kama wanaweza kupata.

1567
01:17:30,425 --> 01:17:32,300
Na kwa kweli, kama ukiangalia
chini ya Hood,

1568
01:17:32,300 --> 01:17:37,050
kama sisi ni hapa kwa kuangalia
55 tatu baada decimal,

1569
01:17:37,050 --> 01:17:39,990
sisi kweli kuona kwamba hali halisi.

1570
01:17:39,990 --> 01:17:42,610
Sasa kama kando, kama wameweza
milele kuonekana movie--

1571
01:17:42,610 --> 01:17:45,780
wengi pengine have not
lakini Superman 3 baadhi ya miaka iliyopita,

1572
01:17:45,780 --> 01:17:49,500
Richard Pryor kimsingi leveraged hii
ukweli katika kampuni yake ya kuiba kura

1573
01:17:49,500 --> 01:17:53,500
ya namba sehemu na namba sehemu ya pennies,
kwa sababu company-- kama mimi kukumbuka,

1574
01:17:53,500 --> 01:17:57,210
imekuwa ni while-- alikuwa kimsingi
kutupa mbali chochote ambacho hakuwa fit

1575
01:17:57,210 --> 01:17:58,790
katika dhana ya senti.

1576
01:17:58,790 --> 01:18:01,480
>> Lakini kama wewe kuongeza hadi haya yote
vidogo, vidogo, idadi vidogo tena,

1577
01:18:01,480 --> 01:18:04,960
na tena, na tena, unaweza, kama katika
kesi yake, kufanya kiasi nzuri ya fedha.

1578
01:18:04,960 --> 01:18:08,010
>> Hiyo wazo moja alikuwa ripped off kwa
zaidi ya hivi karibuni, lakini bado sasa wakubwa

1579
01:18:08,010 --> 01:18:10,500
movie, iitwayo Ofisi Space,
ambapo guys katika movie kwamba,

1580
01:18:10,500 --> 01:18:13,501
akafanya vivyo hivyo, Star it up
kabisa, kuishia na njia sana

1581
01:18:13,501 --> 01:18:14,666
fedha katika akaunti zao za benki.

1582
01:18:14,666 --> 01:18:15,800
Ni mara zote tuhuma sana.

1583
01:18:15,800 --> 01:18:19,290
Lakini mwisho wa siku,
imprecision ni karibu nasi.

1584
01:18:19,290 --> 01:18:22,240
>> Na kwamba, pia, wanaweza kuwa
frighteningly kesi.

1585
01:18:22,240 --> 01:18:25,590
Ni zinageuka kuwa Superman 3
na Ofisi Space kando, kuna

1586
01:18:25,590 --> 01:18:28,460
inaweza kuwa baadhi halisi sana
ramifications dunia

1587
01:18:28,460 --> 01:18:32,290
ya hali halisi ya imprecise
uwakilishi wa data

1588
01:18:32,290 --> 01:18:34,770
kwamba hata sisi binadamu kwa
leo si lazima

1589
01:18:34,770 --> 01:18:38,230
kuelewa kama vile inavyopaswa,
au kukumbuka kama mara nyingi kama inavyopaswa.

1590
01:18:38,230 --> 01:18:42,950
Na kwa kweli, kipande cha ifuatayo ni
kutoka kuangalia dunia baadhi sana halisi

1591
01:18:42,950 --> 01:18:47,730
ramifications ya kile kinachotokea kama wewe
hawana kufahamu kutokuwa sahihi kwamba

1592
01:18:47,730 --> 01:18:50,065
yanaweza kutokea katika idadi ya uwakilishi.

1593
01:18:50,065 --> 01:18:51,300
>> [VIDEO avspelning]

1594
01:18:51,300 --> 01:18:55,620
>> -Computers, Tumekuwa wote wamekuja kukubali
matatizo mara nyingi frustrating kwamba

1595
01:18:55,620 --> 01:19:00,310
kwenda na mende them--, virusi,
na programu glitches,

1596
01:19:00,310 --> 01:19:03,130
kwa bei ndogo ya kulipa
kwa urahisi.

1597
01:19:03,130 --> 01:19:07,800
Lakini katika tech ya juu na mwendo wa kasi
kijeshi na mpango nafasi maombi,

1598
01:19:07,800 --> 01:19:12,800
tatizo ndogo Unaweza
kuwa kujitukuza katika janga.

1599
01:19:12,800 --> 01:19:18,900
>> Tarehe 4 Juni, 1996, wanasayansi tayari
kuzindua unmanned Ariane 5 roketi.

1600
01:19:18,900 --> 01:19:21,220
Ni alikuwa amebeba kisayansi
satelaiti iliyoundwa

1601
01:19:21,220 --> 01:19:24,600
kujua kwa usahihi jinsi
dunia magnetic interacts shamba

1602
01:19:24,600 --> 01:19:27,410
na upepo nishati ya jua.

1603
01:19:27,410 --> 01:19:30,800
roketi ilijengwa kwa
European Space Agency,

1604
01:19:30,800 --> 01:19:34,370
na lile mbali kutoka kituo yake
katika pwani ya Kifaransa.

1605
01:19:34,370 --> 01:19:37,540
>> -Katika Kuhusu 37 sekunde katika
ndege, kwanza

1606
01:19:37,540 --> 01:19:39,270
niliona kitu kinachoendelea vibaya.

1607
01:19:39,270 --> 01:19:42,250
nozzles walikuwa swiveling katika
njia ya wao kweli hawapaswi.

1608
01:19:42,250 --> 01:19:46,580
Karibu sekunde 40 ndani ya ndege,
wazi, gari ilikuwa kwenye matatizo.

1609
01:19:46,580 --> 01:19:48,850
>> Na kwamba wakati wao alifanya
uamuzi wa kuiharibu.

1610
01:19:48,850 --> 01:19:52,780
mbalimbali afisa usalama, na
guts kubwa, taabu kifungo,

1611
01:19:52,780 --> 01:19:58,150
akapiga juu ya roketi, kabla naweza
kuwa hatari kwa usalama wa umma.

1612
01:19:58,150 --> 01:20:01,060
>> -Hii Alikuwa ni mwanamwali
safari ya Ariane 5.

1613
01:20:01,060 --> 01:20:03,960
Na uharibifu wake alichukua
mahali kwa sababu ya flaw

1614
01:20:03,960 --> 01:20:05,822
iliyoingia katika programu roketi.

1615
01:20:05,822 --> 01:20:08,280
-The Tatizo juu ya Ariane ilikuwa
kuwa kulikuwa na idadi hiyo

1616
01:20:08,280 --> 01:20:10,600
required 64 bits kueleza.

1617
01:20:10,600 --> 01:20:13,590
Na walitaka kubadilisha
kwa idadi 16-bit.

1618
01:20:13,590 --> 01:20:15,610
Wao kudhani kuwa
idadi ilikuwa kamwe kwenda

1619
01:20:15,610 --> 01:20:20,980
kuwa kubwa sana, kwamba wengi wa wale
tarakimu katika idadi 64-bit walikuwa zeroes.

1620
01:20:20,980 --> 01:20:22,440
Walikosea.

1621
01:20:22,440 --> 01:20:25,060
>> -The Kutokuwa na uwezo wa moja
mpango wa programu kukubali

1622
01:20:25,060 --> 01:20:29,510
aina ya idadi yanayotokana na
mwingine alikuwa katika mizizi ya kushindwa.

1623
01:20:29,510 --> 01:20:34,350
Programu ya maendeleo imekuwa
sehemu ya gharama kubwa sana ya teknolojia mpya.

1624
01:20:34,350 --> 01:20:38,140
roketi Ariane wamekuwa sana
mafanikio, hivyo mengi ya programu

1625
01:20:38,140 --> 01:20:41,550
kuundwa kwa ilivyokuwa pia
kutumika katika Ariane 5.

1626
01:20:41,550 --> 01:20:47,940
>> -The Tatizo la msingi ilikuwa kwamba Ariane
5 mara kwa kasi, kuharakisha kasi zaidi.

1627
01:20:47,940 --> 01:20:51,450
Na programu na si
waliendelea kwa ajili hiyo.

1628
01:20:51,450 --> 01:20:55,060
>> -The Uharibifu wa roketi
ilikuwa kubwa maafa ya kifedha,

1629
01:20:55,060 --> 01:20:58,790
wote kutokana na hitilafu dakika programu.

1630
01:20:58,790 --> 01:21:01,210
Lakini hii haikuwa kwanza
matatizo wakati data kubadilika

1631
01:21:01,210 --> 01:21:04,820
alikuwa wanakumbana kisasa roketi teknolojia.

1632
01:21:04,820 --> 01:21:08,050
>> -Katika 1991, na kuanza
ya kwanza Vita ya Ghuba,

1633
01:21:08,050 --> 01:21:10,570
Patriot kombora
uzoefu aina sawa

1634
01:21:10,570 --> 01:21:12,800
cha tatizo idadi kubadilika.

1635
01:21:12,800 --> 01:21:16,090
Na matokeo yake, 28 watu,
askari 28 wa Marekani,

1636
01:21:16,090 --> 01:21:19,080
waliuawa, na kuhusu
100 wengine kujeruhiwa,

1637
01:21:19,080 --> 01:21:22,780
wakati Patriot, ambayo ilitakiwa
kulinda dhidi ya Scuds zinazoingia,

1638
01:21:22,780 --> 01:21:25,830
alishindwa kwa moto kombora.

1639
01:21:25,830 --> 01:21:31,670
>> -Wakati Iraq walivamia Kuwait, na Amerika
ilizindua Desert Storm katika mapema 1991,

1640
01:21:31,670 --> 01:21:35,780
betri Patriot kombora walikuwa uliotumika
kulinda Saudi Arabia na Israel

1641
01:21:35,780 --> 01:21:39,230
kutoka Iraq Scud mashambulizi kombora.

1642
01:21:39,230 --> 01:21:43,810
Patriot ni Marekani kati-mbalimbali
uso kwa hewa mfumo, viwandani

1643
01:21:43,810 --> 01:21:45,770
na kampuni Raytheon.

1644
01:21:45,770 --> 01:21:52,340
>> -The Ukubwa wa interceptor Patriot
yenyewe ni kuhusu takribani 20 miguu kwa muda mrefu.

1645
01:21:52,340 --> 01:21:55,230
Na ni kizito kuhusu £ 2000..

1646
01:21:55,230 --> 01:21:59,320
Na hubeba warhead ya juu,
Nadhani ni takribani £ 150..

1647
01:21:59,320 --> 01:22:03,930
Na warhead yenyewe ni
kulipuka, ambayo

1648
01:22:03,930 --> 01:22:07,330
ina vipande kuzunguka.

1649
01:22:07,330 --> 01:22:11,680
casing ya warhead ni
iliyoundwa na kutenda kama buckshot.

1650
01:22:11,680 --> 01:22:14,110
>> makombora -The ni uliofanywa
nne kwa chombo,

1651
01:22:14,110 --> 01:22:17,130
na ni kusafirishwa kwa Trailer nusu.

1652
01:22:17,130 --> 01:22:24,930
>> -The Mfumo Patriot kupambana na kombora
inakwenda nyuma angalau miaka 20 sasa.

1653
01:22:24,930 --> 01:22:28,420
Ni awali ilikuwa iliyoundwa
kama hewa ulinzi kombora

1654
01:22:28,420 --> 01:22:30,720
kwa risasi chini ndege ya adui.

1655
01:22:30,720 --> 01:22:34,500
Katika kwanza Vita ya Ghuba,
wakati vita kwamba alikuja pamoja,

1656
01:22:34,500 --> 01:22:39,745
Jeshi alitaka kuitumia
risasi chini Scuds, si ndege.

1657
01:22:39,745 --> 01:22:43,620
>> Iraq Jeshi la Anga alikuwa
si sana ya tatizo.

1658
01:22:43,620 --> 01:22:46,670
Lakini Jeshi alikuwa na wasiwasi kuhusu Scuds.

1659
01:22:46,670 --> 01:22:50,170
Na hivyo walijaribu
kuboresha Patriot.

1660
01:22:50,170 --> 01:22:52,800
>> -Intercepting adui
kombora kusafiri saa mach 5

1661
01:22:52,800 --> 01:22:55,830
alikuwa anaenda kuwa changamoto ya kutosha.

1662
01:22:55,830 --> 01:22:58,490
Lakini wakati Patriot
alikimbizwa katika huduma,

1663
01:22:58,490 --> 01:23:02,860
Jeshi hakuwa na ufahamu wa
Iraq muundo kwamba alifanya

1664
01:23:02,860 --> 01:23:05,930
Scuds yao karibu haiwezekani hit.

1665
01:23:05,930 --> 01:23:10,740
>> -Nini Kilichotokea ni Scuds kwamba
walikuwa kuja katika walikuwa imara.

1666
01:23:10,740 --> 01:23:11,692
Walikuwa tikisika.

1667
01:23:11,692 --> 01:23:14,910
Sababu ya hayo ni
Raia wa Iraq, ili

1668
01:23:14,910 --> 01:23:18,280
kupata 600 kilomita
nje ya kilomita 300

1669
01:23:18,280 --> 01:23:21,700
mbalimbali kombora, alichukua uzito
nje ya warhead mbele.

1670
01:23:21,700 --> 01:23:23,390
Walitoa warhead nyepesi.

1671
01:23:23,390 --> 01:23:27,330
>> Hivyo sasa Patriot ni
kujaribu kuja katika Scud.

1672
01:23:27,330 --> 01:23:30,230
Na zaidi ya muda,
balaa wengi wa wakati,

1673
01:23:30,230 --> 01:23:32,940
ingekuwa tu kuruka kwa Scud.

1674
01:23:32,940 --> 01:23:37,260
Mara baada ya mfumo wa Patriot waendeshaji
barabara Patriot amekosa lengo lake,

1675
01:23:37,260 --> 01:23:41,690
wao detonated warhead Patriot ya
ili kuepuka majeruhi iwezekanavyo ikiwa ni

1676
01:23:41,690 --> 01:23:44,570
aliruhusiwa kuanguka chini.

1677
01:23:44,570 --> 01:23:48,790
>> -Kwamba Alikuwa nini watu wengi aliona,
wale fireballs kubwa katika anga,

1678
01:23:48,790 --> 01:23:54,550
na kutoeleweka kama
intercepts ya warheads Scud.

1679
01:23:54,550 --> 01:23:56,630
>> -ingawa Katika usiku
anga, Patriots alionekana

1680
01:23:56,630 --> 01:24:00,370
kuwa mafanikio
kuharibu Scuds, saa Dhahran,

1681
01:24:00,370 --> 01:24:03,360
kuna inaweza kuwa hakuna kosa
kuhusu utendaji wake.

1682
01:24:03,360 --> 01:24:07,970
Huko, mfumo wa rada Patriot ya
waliopotea wimbo wa Scud zinazoingia,

1683
01:24:07,970 --> 01:24:10,721
na kamwe ilizindua kutokana
kwa programu flaw.

1684
01:24:10,721 --> 01:24:14,090

1685
01:24:14,090 --> 01:24:18,940
Ilikuwa Israel ambao kwanza aligundua
kwamba tena mfumo ilikuwa juu,

1686
01:24:18,940 --> 01:24:22,690
zaidi wakati tofauti
akawa, kutokana na saa iliyoingia

1687
01:24:22,690 --> 01:24:24,810
katika mfumo wa kompyuta ya.

1688
01:24:24,810 --> 01:24:28,210
>> -About Wiki mbili kabla ya
janga katika Dhahran,

1689
01:24:28,210 --> 01:24:30,770
Israel kuripotiwa kwa
Wizara ya ulinzi

1690
01:24:30,770 --> 01:24:32,590
kwamba mfumo alikuwa kupoteza muda.

1691
01:24:32,590 --> 01:24:35,360
Baada ya masaa nane au kukimbia,
waligundua kuwa mfumo

1692
01:24:35,360 --> 01:24:37,720
ilikuwa kuwa noticeably chini sahihi.

1693
01:24:37,720 --> 01:24:41,900
Idara ya Ulinzi alijibu kwa
kuwaambia yote ya betri Patriot

1694
01:24:41,900 --> 01:24:44,950
na si kuondoka mifumo
juu ya kwa muda mrefu.

1695
01:24:44,950 --> 01:24:49,160
Wao kamwe alisema nini muda mrefu was--
masaa nane, masaa 10, masaa 1,000.

1696
01:24:49,160 --> 01:24:51,360
Hakuna anayejua.

1697
01:24:51,360 --> 01:24:53,380
>> -The Betri Patriot
stationed katika kambi ya

1698
01:24:53,380 --> 01:24:58,350
katika Dhahran na kiujanja yake ya ndani
saa alikuwa juu zaidi ya masaa 100

1699
01:24:58,350 --> 01:25:01,670
juu ya usiku wa Februari 25..

1700
01:25:01,670 --> 01:25:05,917
>> -Ni Na msisimko wakati wa usahihi
ya juu kumi ya pili.

1701
01:25:05,917 --> 01:25:08,000
Sasa, kumi ya pili
ni namba ya kuvutia,

1702
01:25:08,000 --> 01:25:11,920
kwa sababu haiwezi kuwa walionyesha
katika binary hasa, ambayo

1703
01:25:11,920 --> 01:25:16,820
ina maana haiwezi kuwa walionyesha hasa
katika yoyote kisasa ya digital kompyuta.

1704
01:25:16,820 --> 01:25:18,540
Ni vigumu kuamini.

1705
01:25:18,540 --> 01:25:21,210
>> Lakini kutumia hii kama mfano.

1706
01:25:21,210 --> 01:25:23,540
Hebu kuchukua namba moja ya tatu.

1707
01:25:23,540 --> 01:25:27,350
theluthi moja hawezi kuwa
walionyesha katika decimal hasa.

1708
01:25:27,350 --> 01:25:32,080
Moja ya tatu ni 0.333
ikiendelea kwa infinity.

1709
01:25:32,080 --> 01:25:36,480
>> Hakuna njia ya kufanya hivyo na
usahihi kabisa katika decimal.

1710
01:25:36,480 --> 01:25:39,560
Hiyo hasa aina ya tatizo
yaliyotokea katika Patriot.

1711
01:25:39,560 --> 01:25:44,100
tena mfumo mbio,
mbaya kosa wakati akawa.

1712
01:25:44,100 --> 01:25:48,890
>> -Baada Masaa 100 ya operesheni,
makosa katika wakati ilikuwa tu theluthi moja

1713
01:25:48,890 --> 01:25:50,600
ya pili.

1714
01:25:50,600 --> 01:25:54,210
Lakini katika suala la kulenga
kombora kusafiri saa mach 5,

1715
01:25:54,210 --> 01:25:58,710
ni matokeo ya kufuatilia
makosa ya zaidi ya 600 mita.

1716
01:25:58,710 --> 01:26:02,120
Itakuwa kosa mbaya
kwa askari juu ya nini

1717
01:26:02,120 --> 01:26:08,940
kilichotokea ni Scud uzinduzi alikuwa
wanaona na mapema Onyo satelaiti

1718
01:26:08,940 --> 01:26:12,860
na walijua kuwa Scud alikuwa
kuja katika uongozi wao kwa ujumla.

1719
01:26:12,860 --> 01:26:15,320
Hawakujua ambako alikuwa anakuja.

1720
01:26:15,320 --> 01:26:18,250
>> -Ni Ilikuwa sasa hadi rada
sehemu ya mfumo Patriot

1721
01:26:18,250 --> 01:26:23,190
kutetea Dhahran na Machapisho na kuweka
wimbo wa zinazoingia kombora adui.

1722
01:26:23,190 --> 01:26:24,609
>> -The Rada alikuwa smart sana.

1723
01:26:24,609 --> 01:26:26,650
Ingekuwa kweli kufuatilia
nafasi ya Scud,

1724
01:26:26,650 --> 01:26:30,350
na kisha kutabiri ambapo pengine
itakuwa wakati ujao rada alimtuma

1725
01:26:30,350 --> 01:26:31,420
a mapigo nje.

1726
01:26:31,420 --> 01:26:33,110
Aliyeitwa lango mbalimbali.

1727
01:26:33,110 --> 01:26:37,660
>> -Then, Mara moja Patriot
anaamua muda wa kutosha ina

1728
01:26:37,660 --> 01:26:42,450
kupita kwenda nyuma na kuangalia ijayo
eneo kwa ajili ya kitu hicho wanaona,

1729
01:26:42,450 --> 01:26:43,600
unaendelea nyuma.

1730
01:26:43,600 --> 01:26:48,650
Hivyo wakati akarudi vibaya
mahali, basi anaona hakuna kitu.

1731
01:26:48,650 --> 01:26:52,160
Na anaamua kwamba kulikuwa hakuna
kitu, ilikuwa kugundua uongo,

1732
01:26:52,160 --> 01:26:53,930
na matone kufuatilia.

1733
01:26:53,930 --> 01:26:57,030
>> -The Scud zinazoingia kutoweka
kutoka screen rada.

1734
01:26:57,030 --> 01:27:00,260
Na sekunde baadaye,
slammed ndani ya ngome.

1735
01:27:00,260 --> 01:27:06,150
Scud kuuawa 28, na mara ya mwisho
moja fired wakati kwanza Vita vya Ghuba.

1736
01:27:06,150 --> 01:27:11,960
>> Kusikitisha, programu updated
aliwasili katika Dhahran siku iliyofuata.

1737
01:27:11,960 --> 01:27:14,930
programu flaw alikuwa
wamekuwa fasta, kufunga

1738
01:27:14,930 --> 01:27:19,806
sura ya kwanza katika wasiwasi
historia ya kombora Patriot.

1739
01:27:19,806 --> 01:27:20,729
>> [VIDEO avspelning]

1740
01:27:20,729 --> 01:27:23,520
DAVID J. Malan: Hivyo hii yote ni kwa
kusema kwamba masuala haya ya kufurika

1741
01:27:23,520 --> 01:27:25,860
na kutokuwa sahihi wote ni kweli pia.

1742
01:27:25,860 --> 01:27:26,920
Hivyo ni jinsi gani sisi kupata hapa?

1743
01:27:26,920 --> 01:27:28,895
Sisi ilianza na tu kuzungumza juu ya printf.

1744
01:27:28,895 --> 01:27:31,270
Tena, kazi hii kwamba
Prints kitu screen,

1745
01:27:31,270 --> 01:27:33,450
na sisi ilianzisha baada ya hapo
chache kazi nyingine

1746
01:27:33,450 --> 01:27:34,945
kutoka kinachojulikana maktaba CS50.

1747
01:27:34,945 --> 01:27:36,910
Na tutaweza kuendelea
kuona haya kwa wakati wake.

1748
01:27:36,910 --> 01:27:40,760
Na sisi, hasa, kutumika kupata kamba,
na kupata int, na sasa pia kupata kuelea,

1749
01:27:40,760 --> 01:27:44,410
na bado wengine bado sisi kukutana
na kutumia wenyewe kabla ya muda mrefu.

1750
01:27:44,410 --> 01:27:47,220
>> Lakini katika tukio, na
sisi tayari kuona haja

1751
01:27:47,220 --> 01:27:50,520
kuhifadhi kile kazi hizo upande nyuma?

1752
01:27:50,520 --> 01:27:52,920
Wao mkono sisi nyuma kamba,
au int, au kuelea.

1753
01:27:52,920 --> 01:27:56,070
Na wakati mwingine tunahitaji kuweka kwamba
kamba, au int, au kuelea, mahali fulani.

1754
01:27:56,070 --> 01:28:00,100
>> Na kuhifadhi mambo hayo, tunakumbuka tu
kama katika Scratch, tuna vigezo.

1755
01:28:00,100 --> 01:28:03,260
Lakini tofauti na katika Scratch,
katika C tuna aina halisi

1756
01:28:03,260 --> 01:28:05,530
ya data variables--
aina, generally-- zaidi

1757
01:28:05,530 --> 01:28:08,640
kati yao, kamba, int, a
kuelea, na hawa wengine bado.

1758
01:28:08,640 --> 01:28:12,321
>> Na hivyo wakati sisi kutangaza vigezo katika C,
tutaweza kutangaza aina yetu data.

1759
01:28:12,321 --> 01:28:14,820
Hii si kitu tutaweza
una kufanya baadaye katika muhula

1760
01:28:14,820 --> 01:28:16,810
kama sisi mpito kwa lugha nyingine.

1761
01:28:16,810 --> 01:28:19,610
Lakini kwa sasa, hatuna haja
kwa priori mapema,

1762
01:28:19,610 --> 01:28:24,370
kuelezea kwa kompyuta ni aina gani
ya kutofautiana tunataka kwa kutupa.

1763
01:28:24,370 --> 01:28:27,290
>> Sasa, wakati huo huo, na magazeti
aina wale wa aina ya data,

1764
01:28:27,290 --> 01:28:29,570
tuna kuwaambia printf nini cha kutarajia.

1765
01:28:29,570 --> 01:28:32,450
Na tuliona asilimia s kwa masharti,
na asilimia i kwa integers,

1766
01:28:32,450 --> 01:28:33,790
na wengine wachache tayari.

1767
01:28:33,790 --> 01:28:37,237
Na wale ni tu mahitaji
kwa ajili ya kuwasilisha Visual

1768
01:28:37,237 --> 01:28:38,070
wa habari kwamba.

1769
01:28:38,070 --> 01:28:42,080
>> Na kila moja ya haya kweli anaweza
parametrized au tweaked kwa namna fulani,

1770
01:28:42,080 --> 01:28:45,370
kama unataka zaidi udhibiti
aina ya pato kwamba kupata.

1771
01:28:45,370 --> 01:28:49,604
Na, kwa kweli, ni zamu nje kwamba sio tu
ni pale backslash n kwa mstari mpya.

1772
01:28:49,604 --> 01:28:52,520
Kuna kitu kingine aitwaye backslash
r kwa kurudi carriage, ambayo

1773
01:28:52,520 --> 01:28:54,360
ni sawa na zaidi
typewriter umri wa shule,

1774
01:28:54,360 --> 01:28:57,690
na pia Windows kutumika kwa miaka mingi.

1775
01:28:57,690 --> 01:28:59,690
>> Kuna backslash t kwa tabo.

1776
01:28:59,690 --> 01:29:03,170
Zamu nje, kwamba kama unataka
mara mbili quote ndani ya kamba,

1777
01:29:03,170 --> 01:29:05,000
kukumbuka kwamba tumekuwa kutumika
mara mbili quote mara mbili

1778
01:29:05,000 --> 01:29:07,900
quote juu ya kushoto na kulia
kuishia ya masharti yetu hivi sasa.

1779
01:29:07,900 --> 01:29:09,420
Ambayo wanaonekana kuwachanganya mambo.

1780
01:29:09,420 --> 01:29:12,503
>> Kama unataka kuweka quote mara mbili katika
katikati ya kamba na kwa kweli,

1781
01:29:12,503 --> 01:29:13,670
ni utata kuona.

1782
01:29:13,670 --> 01:29:17,120
Na hivyo una kutoroka, hivyo
kusema, kunukuu mara mbili na kitu

1783
01:29:17,120 --> 01:29:18,860
kama, literally, backslash mara mbili quote.

1784
01:29:18,860 --> 01:29:20,230
Na kuna wengine wachache bado.

1785
01:29:20,230 --> 01:29:24,540
Na tutaweza kuona zaidi ya wale
katika matumizi halisi kabla ya muda mrefu.

1786
01:29:24,540 --> 01:29:27,930
>> Basi hebu sasa mpito kutoka
data, na uwakilishi,

1787
01:29:27,930 --> 01:29:30,820
na watoa huduma hesabu, kila
ya aliyetupa baadhi ya kujenga

1788
01:29:30,820 --> 01:29:32,070
vitalu na ambayo kwa kucheza.

1789
01:29:32,070 --> 01:29:34,481
Lakini sasa hebu kweli kutoa
sisi wengine wa msamiati

1790
01:29:34,481 --> 01:29:36,230
kwamba sisi tayari alikuwa
wiki iliyopita na Scratch

1791
01:29:36,230 --> 01:29:39,350
kwa kuangalia baadhi ya wengine
constructs katika C-- si wote.

1792
01:29:39,350 --> 01:29:41,680
Lakini mawazo tuko
juu ya kuona kweli tu

1793
01:29:41,680 --> 01:29:45,610
kusisitiza tafsiri kutoka
lugha moja, Scratch, na mwingine, C.

1794
01:29:45,610 --> 01:29:48,470
>> Na baada ya muda, tutaweza kuchukua
zana zaidi kwa toolkit yetu,

1795
01:29:48,470 --> 01:29:49,820
hivyo kusema, syntactically.

1796
01:29:49,820 --> 01:29:54,190
Na, kwa hakika, utaona kwamba mawazo
sasa badala ukoo kutoka wiki iliyopita.

1797
01:29:54,190 --> 01:29:55,200
Basi hebu kufanya hili.

1798
01:29:55,200 --> 01:29:58,870
>> Hebu kwenda mbele na mjeledi juu ya mpango
kwamba kweli anatumia baadhi maneno,

1799
01:29:58,870 --> 01:30:00,720
Kujieleza Boolean.

1800
01:30:00,720 --> 01:30:02,810
Hebu kwenda mbele hapa
na kuunda faili mpya.

1801
01:30:02,810 --> 01:30:06,090
Mimi nitakuita condition.c hii.

1802
01:30:06,090 --> 01:30:09,350
>> Hebu kwenda mbele na
pamoja na maktaba CS50.

1803
01:30:09,350 --> 01:30:12,640
Na napenda kwenda mbele na ni pamoja na
kiwango io.h kwa ajili ya kazi yetu,

1804
01:30:12,640 --> 01:30:14,690
na printf, na zaidi kwa mtiririko huo.

1805
01:30:14,690 --> 01:30:18,900
Nikupe mwenyewe kwamba boilerplate ya
int kuu utupu, ambaye maelezo tutaweza

1806
01:30:18,900 --> 01:30:20,360
kurudi katika siku zijazo.

1807
01:30:20,360 --> 01:30:23,820
>> Sasa basi mimi kwenda mbele na kutoa
mwenyewe int kupitia kupata int.

1808
01:30:23,820 --> 01:30:25,970
Kisha basi mimi kwenda mbele na kufanya hili.

1809
01:30:25,970 --> 01:30:30,150
Nataka kusema kama i ni less-- hebu
kutofautisha kati ya chanya, hasi,

1810
01:30:30,150 --> 01:30:31,260
au zero maadili.

1811
01:30:31,260 --> 01:30:36,630
>> Hivyo kama i ni chini ya sifuri, napenda
tu na mpango huu tu kusema,

1812
01:30:36,630 --> 01:30:42,370
hasi, backslash n, mwingine
kama i ni kubwa kuliko sufuri.

1813
01:30:42,370 --> 01:30:47,030
Sasa mimi nina, bila shaka, kwenda kusema
printf chanya, backslash n.

1814
01:30:47,030 --> 01:30:50,690
Na kisha mwingine if-- mimi naweza kufanya hili.

1815
01:30:50,690 --> 01:30:53,410
>> Mimi naweza kufanya kama i sawa 0.

1816
01:30:53,410 --> 01:30:55,840
Lakini Ningependa kuwa maamuzi katika
angalau moja makosa tayari.

1817
01:30:55,840 --> 01:30:59,480
Kumbuka kwamba ishara sawa ni
si sawa, kama sisi binadamu kujua.

1818
01:30:59,480 --> 01:31:01,010
>> Lakini ni operator zoezi.

1819
01:31:01,010 --> 01:31:05,640
Na hatutaki kuchukua 0 juu ya
haki na kuiweka katika i upande wa kushoto.

1820
01:31:05,640 --> 01:31:11,810
Hivyo ili kuepuka malumbano haya, au
labda matumizi mabaya ya alama ya usawa,

1821
01:31:11,810 --> 01:31:14,740
binadamu aliamua baadhi ya miaka iliyopita
kwamba katika lugha nyingi programu

1822
01:31:14,740 --> 01:31:18,000
wakati unataka kuangalia usawa wa
kati ya kushoto na kulia,

1823
01:31:18,000 --> 01:31:19,635
wewe kweli kutumia sawa sawa.

1824
01:31:19,635 --> 01:31:21,010
Hivyo kugonga alama ya usawa mara mbili.

1825
01:31:21,010 --> 01:31:25,600
Wakati unataka hawawajui kutoka kulia
kwa upande wa kushoto, unaweza kutumia moja sawa ishara.

1826
01:31:25,600 --> 01:31:29,360
Hivyo tunaweza kufanya Haya kingine
kama i ni sawa sawa na sifuri.

1827
01:31:29,360 --> 01:31:31,710
>> Mimi naweza kisha kwenda na
kufungua braces yangu curly,

1828
01:31:31,710 --> 01:31:36,087
na kusema, printf 0, backslash n, kufanyika.

1829
01:31:36,087 --> 01:31:38,170
Lakini kumbuka jinsi haya
forks katika barabara hawezi kufanya kazi.

1830
01:31:38,170 --> 01:31:39,836
Na, kwa kweli, tu kufikiri kuhusu mantiki.

1831
01:31:39,836 --> 01:31:41,510
i ni idadi.

1832
01:31:41,510 --> 01:31:43,320
Ni integer, hasa.

1833
01:31:43,320 --> 01:31:48,600
Na hiyo ina maana itakuja kuwa chini
kuliko 0, au mkubwa kuliko 0, au 0.

1834
01:31:48,600 --> 01:31:51,600
Kwa hiyo, kuna aina ya hii
an alisema default kesi.

1835
01:31:51,600 --> 01:31:54,920
>> Na hivyo tunaweza, kama tu
Scratch, kujitenga na mwingine kama,

1836
01:31:54,920 --> 01:31:55,747
na kusema tu mwingine.

1837
01:31:55,747 --> 01:31:57,830
Kimantiki, kama wewe
programu kujua kuna tu

1838
01:31:57,830 --> 01:32:01,635
ndoo tatu ndani ambayo a
scenario unaweza fall-- kwanza,

1839
01:32:01,635 --> 01:32:03,510
pili, au ya tatu
katika hii case-- hawana

1840
01:32:03,510 --> 01:32:07,100
kujisumbua na kuongeza usahihi wa ziada
na mantiki ya ziada huko.

1841
01:32:07,100 --> 01:32:09,690
Tu kwenda mbele na
default kesi hapa ya mwingine.

1842
01:32:09,690 --> 01:32:11,950
>> Sasa, hebu kwenda mbele
baada ya kuokoa hii, kufanya

1843
01:32:11,950 --> 01:32:15,760
hali dot kufyeka conditions--
si kubwa user interface,

1844
01:32:15,760 --> 01:32:18,914
kwa sababu mimi si hivyo kusababisha
user, kama nilivyoeleza awali.

1845
01:32:18,914 --> 01:32:19,580
Lakini hiyo ni faini.

1846
01:32:19,580 --> 01:32:20,454
Tutaweza kushika ni rahisi.

1847
01:32:20,454 --> 01:32:21,890
Hebu jaribu namba 42.

1848
01:32:21,890 --> 01:32:23,240
Na kwamba ni chanya.

1849
01:32:23,240 --> 01:32:26,120
Hebu jaribu idadi
hasi 42, hasi.

1850
01:32:26,120 --> 01:32:28,244
>> Hebu jaribu thamani 0.

1851
01:32:28,244 --> 01:32:29,160
Na, kwa hakika, ni kazi.

1852
01:32:29,160 --> 01:32:33,900
Sasa, utaona na matatizo kabla
muda mrefu, kupima mambo mara tatu,

1853
01:32:33,900 --> 01:32:34,980
pengine si ya kutosha.

1854
01:32:34,980 --> 01:32:37,438
Pengine wanataka mtihani baadhi
idadi kubwa, baadhi ndogo

1855
01:32:37,438 --> 01:32:40,520
idadi, baadhi ya kesi kona, kama
tutaweza kuja kuelezea yao.

1856
01:32:40,520 --> 01:32:42,500
>> Lakini kwa sasa, hii ni
pretty rahisi mpango.

1857
01:32:42,500 --> 01:32:45,160
Na mimi nina uhakika pretty, mantiki,
kuwa ni unaingia kesi tatu.

1858
01:32:45,160 --> 01:32:49,360
Na, kwa hakika, hata kama sisi tu
ililenga downsides uwezo

1859
01:32:49,360 --> 01:32:53,480
ya kutokuwa sahihi na kufurika, katika
ukweli ambapo matatizo mengi CS50,

1860
01:32:53,480 --> 01:32:56,000
sisi si kwenda kuwa na wasiwasi
kuhusu, wakati wote,

1861
01:32:56,000 --> 01:32:59,050
wale masuala ya kufurika na
kutokuwa sahihi, kwa sababu, kwa kweli, katika C,

1862
01:32:59,050 --> 01:33:01,889
ni kweli si wote kwamba
rahisi kuepuka mambo hayo.

1863
01:33:01,889 --> 01:33:04,180
Kama unataka kuhesabu hadi
kubwa zaidi, na kubwa zaidi, na kubwa zaidi,

1864
01:33:04,180 --> 01:33:07,510
ni zamu nje kuna mbinu wewe
Unaweza kutumia, mara nyingi kuwashirikisha mambo kuitwa

1865
01:33:07,510 --> 01:33:11,240
maktaba, makusanyo ya kificho, kwamba
watu wengine aliandika kwamba unaweza kutumia,

1866
01:33:11,240 --> 01:33:13,910
na lugha nyingine kama
Java na wengine, kwa kweli

1867
01:33:13,910 --> 01:33:15,800
kufanya ni rahisi sana
kuhesabu hata ya juu.

1868
01:33:15,800 --> 01:33:19,810
Hivyo ni kweli ni baadhi ya hatari hizi
kazi ya lugha unayotumia.

1869
01:33:19,810 --> 01:33:22,710
Na katika wiki ijayo, tutaweza
kuona jinsi ya hatari C kweli

1870
01:33:22,710 --> 01:33:24,950
inaweza kuwa kama huna kutumia vizuri.

1871
01:33:24,950 --> 01:33:27,610
Lakini kutoka huko, na kwa
Python, na JavaScript, itakuwa

1872
01:33:27,610 --> 01:33:32,620
sisi safu juu ya baadhi ulinzi wa ziada,
na kukimbia wachache wa hatari hizo.

1873
01:33:32,620 --> 01:33:35,820
>> Basi hebu kufanya kidogo zaidi
kuvutia mantiki katika programu yetu.

1874
01:33:35,820 --> 01:33:39,110
Hivyo basi mimi kwenda mbele na kujenga
programu inayoitwa Logical

1875
01:33:39,110 --> 01:33:43,804
tu hivyo siwezi kucheza na baadhi
halisi mantiki, logical.c.

1876
01:33:43,804 --> 01:33:46,870
Mimi itabidi nakala tu na kuweka baadhi
kanuni kutoka mapema hivyo mimi kupata nyuma

1877
01:33:46,870 --> 01:33:49,950
kwa kianzio huu mzuri.

1878
01:33:49,950 --> 01:33:53,980
>> Napenda wakati huu kufanya char C. mimi nina
kwenda kuwapa jina la C

1879
01:33:53,980 --> 01:33:58,510
tu kwa sababu ni ya kawaida,
kupata tabia kutoka kwa mtumiaji.

1880
01:33:58,510 --> 01:34:00,730
Na hebu kujifanya kama
Mimi nina kutekeleza sehemu

1881
01:34:00,730 --> 01:34:04,130
wa mpango huo Rm, kuondoa
mpango kabla kwamba ilisababisha user

1882
01:34:04,130 --> 01:34:05,400
kuondoa faili.

1883
01:34:05,400 --> 01:34:06,750
Inakuwaje sisi kufanya hili?

1884
01:34:06,750 --> 01:34:11,090
>> Nataka kusema, kama C ni sawa na
sawa, quote unquote,

1885
01:34:11,090 --> 01:34:16,304
y, basi mimi nina kwenda kudhani
kwamba mtumiaji amechagua ndiyo.

1886
01:34:16,304 --> 01:34:17,470
Mimi tu kwenda magazeti ndiyo.

1887
01:34:17,470 --> 01:34:19,440
Kama walikuwa kweli kuandika
kuondolewa mpango,

1888
01:34:19,440 --> 01:34:21,420
tunaweza kuondoa faili
na mistari zaidi ya kificho.

1889
01:34:21,420 --> 01:34:22,461
Lakini tutaweza kushika ni rahisi.

1890
01:34:22,461 --> 01:34:25,950

1891
01:34:25,950 --> 01:34:31,250
>> Mwingine kama c ni sawa sawa na n--
na sasa hapa, mimi nina kwenda kusema,

1892
01:34:31,250 --> 01:34:32,980
user lazima kuwa na maana yoyote.

1893
01:34:32,980 --> 01:34:34,360
Na kisha mwingine, unajua nini?

1894
01:34:34,360 --> 01:34:36,200
Sijui kile kingine
user ni kwenda aina.

1895
01:34:36,200 --> 01:34:38,533
Hivyo mimi nina kwenda tu kusema kwamba
kwamba ni makosa, chochote

1896
01:34:38,533 --> 01:34:40,070
yeye au yeye kweli typed.

1897
01:34:40,070 --> 01:34:41,180
>> Hivyo nini kinaendelea hapa?

1898
01:34:41,180 --> 01:34:44,530
Kuna tofauti ya kimsingi
dhidi ya kile nimepata kufanyika katika siku za nyuma.

1899
01:34:44,530 --> 01:34:49,300
Double quotes, quotes mbili, mbili
quotes, na, bado, single quotes,

1900
01:34:49,300 --> 01:34:50,170
single quotes.

1901
01:34:50,170 --> 01:34:52,860
Ni zinageuka katika C, kwamba wakati
unataka kuandika kamba,

1902
01:34:52,860 --> 01:34:56,680
huna kutumia quotes mbili, kama vile tumekuwa
wamekuwa wakitumia muda wote huu na printf.

1903
01:34:56,680 --> 01:35:02,030
>> Lakini kama unataka kukabiliana na tu
tabia moja, kinachojulikana Char,

1904
01:35:02,030 --> 01:35:03,780
basi wewe kweli kutumia quotes moja.

1905
01:35:03,780 --> 01:35:05,450
Wale wa wewe ambao wameweza iliyowekwa
kabla, unaweza kuwa

1906
01:35:05,450 --> 01:35:07,850
alikuwa na wasiwasi kuhusu hili
Tofauti katika lugha fulani.

1907
01:35:07,850 --> 01:35:09,450
Katika C, haina jambo.

1908
01:35:09,450 --> 01:35:12,560
Na hivyo wakati mimi kupata char na mimi nataka
kulinganisha kwamba char kutumia sawa

1909
01:35:12,560 --> 01:35:18,350
sawa na baadhi barua kama y au n, mimi kufanya,
kwa kweli, haja ya kuwa na quotes moja.

1910
01:35:18,350 --> 01:35:19,770
>> Sasa, hebu kwenda mbele na kufanya hili.

1911
01:35:19,770 --> 01:35:26,180
Hebu kwenda mbele na kufanya kufanya
dot mantiki kufyeka mantiki.

1912
01:35:26,180 --> 01:35:27,305
Na sasa mimi nina kuwa ilisababisha.

1913
01:35:27,305 --> 01:35:30,638
Hivyo, labda, bora user uzoefu
ingekuwa kweli kuniambia nini cha kufanya hapa.

1914
01:35:30,638 --> 01:35:33,030
Lakini mimi nina kwenda kwa tu upofu
kusema y kwa ndiyo, OK, nzuri.

1915
01:35:33,030 --> 01:35:35,780
>> Hebu kukimbia tena, n kwa no, nzuri.

1916
01:35:35,780 --> 01:35:39,610
Tuseme kama watu fulani Mimi najua,
kofia yangu kufuli muhimu ni juu ya yote mara nyingi mno.

1917
01:35:39,610 --> 01:35:43,740
Hivyo mimi kufanya mji mkuu Y, kuingia, kosa.

1918
01:35:43,740 --> 01:35:46,130
OK, siyo hasa nini mimi kutarajia.

1919
01:35:46,130 --> 01:35:48,170
Hakika, kompyuta
anafanya literally nini

1920
01:35:48,170 --> 01:35:51,794
Mimi aliiambia yake do-- kuangalia kwa
lowercase y na ndogo n.

1921
01:35:51,794 --> 01:35:53,960
Hii haina kujisikia kama nzuri
user uzoefu, ingawa.

1922
01:35:53,960 --> 01:35:59,010
Napenda kuuliza kwa na kukubali
ama chini kesi au kesi ya juu.

1923
01:35:59,010 --> 01:36:02,090
Hivyo ni zamu nje, unaweza kutaka
kusema kitu kama katika Scratch,

1924
01:36:02,090 --> 01:36:08,150
kama literally au C ni sawa na
sawa na mji mkuu single alinukuliwa y.

1925
01:36:08,150 --> 01:36:11,400
Zamu nje, C hana
keyword hii halisi au.

1926
01:36:11,400 --> 01:36:12,880
>> Lakini ni gani baa mbili wima.

1927
01:36:12,880 --> 01:36:15,463
Una kushikilia Shift kawaida,
kama wewe ni kutumia keyboard Marekani,

1928
01:36:15,463 --> 01:36:18,910
na kugonga bar wima
ufunguo juu ya kurudi ufunguo wako.

1929
01:36:18,910 --> 01:36:22,410
Lakini bar hii wima
wima bar ina maana au.

1930
01:36:22,410 --> 01:36:26,220
>> Kama, kwa kulinganisha, tulitaka
kusema na, kama katika Scratch,

1931
01:36:26,220 --> 01:36:28,180
tunaweza kufanya Ampersand Ampersand.

1932
01:36:28,180 --> 01:36:31,330
Hiyo haina mantiki mantiki hapa,
kwa sababu binadamu hawakuweza uwezekano

1933
01:36:31,330 --> 01:36:37,110
kuwa typed wote wawili y na ndogo y
na mji mkuu Y kama tabia hiyo.

1934
01:36:37,110 --> 01:36:39,470
Hivyo au ni nini tunakusudia hapa.

1935
01:36:39,470 --> 01:36:46,280
>> Hivyo kama mimi kufanya hivyo katika maeneo yote, au c
sawa na sawa na mtaji N, sasa rerun,

1936
01:36:46,280 --> 01:36:49,390
kufanya mantiki, rerun mantiki.

1937
01:36:49,390 --> 01:36:51,200
Sasa, siwezi aina y.

1938
01:36:51,200 --> 01:36:53,920
Na siwezi kufanya hivyo tena na
mji mkuu Y, au mji mkuu N.

1939
01:36:53,920 --> 01:36:56,630
Na mimi naweza kuongeza katika ziada
mchanganyiko bado.

1940
01:36:56,630 --> 01:36:58,810
>> Hivyo hii ni mantiki
mpango kadiri sasa

1941
01:36:58,810 --> 01:37:01,940
Mimi nina kuangalia mantiki kwa
thamani huu au thamani hii.

1942
01:37:01,940 --> 01:37:06,420
Na mimi si kuwa na, lazima,
kuja na ikiwa wawili zaidi au mwingine ikiwa.

1943
01:37:06,420 --> 01:37:09,960
Mimi kweli anaweza kuchanganya baadhi ya
kuhusiana na mantiki pamoja kwa njia hii.

1944
01:37:09,960 --> 01:37:11,950
Hivyo hii itakuwa bora
iliyoundwa kuliko tu

1945
01:37:11,950 --> 01:37:17,490
akisema, ikiwa C ni sawa na chini kesi y,
magazeti ndiyo, mwingine kama c ni sawa na mji mkuu Y,

1946
01:37:17,490 --> 01:37:20,074
magazeti ndiyo, mwingine kama c ni sawa na
lower-- kwa maneno mengine,

1947
01:37:20,074 --> 01:37:21,990
huna kuwa na
zaidi na zaidi matawi.

1948
01:37:21,990 --> 01:37:28,840
Unaweza kuchanganya baadhi ya sawa
matawi mantiki, kama kwa njia hii.

1949
01:37:28,840 --> 01:37:34,150
>> Basi hebu tuangalie moja tu
mwisho kingo, moja ya mwisho kujenga,

1950
01:37:34,150 --> 01:37:34,847
kwamba C inaruhusu.

1951
01:37:34,847 --> 01:37:36,930
Na tutaweza kurudi katika
baadaye kwa wengine bado.

1952
01:37:36,930 --> 01:37:41,400
Na kisha tutaweza kuhitimisha kwa kuangalia
katika si usahihi wa code--

1953
01:37:41,400 --> 01:37:46,070
kupata kanuni kwa work-- lakini kubuni
ya kificho, na kupanda mbegu hizo mapema juu ya.

1954
01:37:46,070 --> 01:37:51,337
>> Hivyo basi mimi kwenda mbele na
kufungua faili mpya hapa.

1955
01:37:51,337 --> 01:37:51,920
Unajua nini?

1956
01:37:51,920 --> 01:37:54,450
Mimi nina kwenda tena kutekeleza
kwamba mpango huo,

1957
01:37:54,450 --> 01:37:55,940
lakini kwa kutumia kujenga tofauti.

1958
01:37:55,940 --> 01:38:00,110
>> Hivyo basi mimi haraka kutoa mwenyewe
upatikanaji wa ni pamoja na CS50.h

1959
01:38:00,110 --> 01:38:04,150
kwa ajili ya maktaba CS50,
kiwango io.h kwa printf.

1960
01:38:04,150 --> 01:38:06,510
Nipe kuu wangu int utupu.

1961
01:38:06,510 --> 01:38:09,310
Na kisha juu hapa, hebu
mimi kwenda mbele na kufanya hili.

1962
01:38:09,310 --> 01:38:12,010
>> Char c anapata kupata char, tu kama ilivyokuwa kabla.

1963
01:38:12,010 --> 01:38:16,770
Na mimi nina kwenda kutumia kujenga mpya
now-- kubadili, juu ya tabia nini?

1964
01:38:16,770 --> 01:38:19,820
Hivyo kubadili ni aina ya kama
byte tracks treni.

1965
01:38:19,820 --> 01:38:22,070
Au, kwa kweli, ni aina ya
an kama mwingine, kama mwingine kama,

1966
01:38:22,070 --> 01:38:23,980
lakini imeandikwa kiasi fulani tofauti.

1967
01:38:23,980 --> 01:38:25,490
>> kubadili inaonekana kama hii.

1968
01:38:25,490 --> 01:38:29,060
Una kubadili, na kisha nini
tabia au idadi unataka kuangalia,

1969
01:38:29,060 --> 01:38:32,000
kisha baadhi braces curly kama katika
Scratch, kusema tu kufanya mambo haya.

1970
01:38:32,000 --> 01:38:33,480
Na kisha una kesi tofauti.

1971
01:38:33,480 --> 01:38:34,830
>> Huwezi kutumia kama na kingine chochote.

1972
01:38:34,830 --> 01:38:37,050
You literally kutumia kesi neno.

1973
01:38:37,050 --> 01:38:38,790
Na ungependa kusema kitu kama hiki.

1974
01:38:38,790 --> 01:38:43,820
>> Hivyo katika kesi ya lowercase y,
au katika kesi ya mji mkuu Y,

1975
01:38:43,820 --> 01:38:47,350
kwenda mbele na magazeti nje ndiyo.

1976
01:38:47,350 --> 01:38:49,020
Na kisha kuvunja nje ya kubadili.

1977
01:38:49,020 --> 01:38:49,580
Hiyo ni.

1978
01:38:49,580 --> 01:38:50,880
Sisi ni kosa.

1979
01:38:50,880 --> 01:38:57,270
>> Mwingine kama, hivyo kusema,
chini kesi n, au mji mkuu N,

1980
01:38:57,270 --> 01:39:02,560
kisha kwenda mbele na magazeti
nje hakuna, na kisha kuvunja.

1981
01:39:02,560 --> 01:39:08,022
Else-- na aina hii ya ni
default kesi indeed-- printf error--

1982
01:39:08,022 --> 01:39:10,980
na tu kwa ajili ya hatua nzuri, ingawa
kifikra mapumziko hii si muhimu

1983
01:39:10,980 --> 01:39:12,896
kwa sababu tuko mwishoni
ya kubadili anyway,

1984
01:39:12,896 --> 01:39:14,520
Mimi sasa kuvunja nje ya kubadili.

1985
01:39:14,520 --> 01:39:16,280
Hivyo hii inaonekana tofauti kidogo.

1986
01:39:16,280 --> 01:39:18,272
>> Lakini, mantiki, ni
kweli sawa.

1987
01:39:18,272 --> 01:39:19,980
Na ni kwa nini matumizi
moja juu ya nyingine?

1988
01:39:19,980 --> 01:39:23,220
Wakati mwingine, tu binafsi upendeleo,
wakati mwingine aesthetics,

1989
01:39:23,220 --> 01:39:25,420
kama mimi mtazamo katika hii
sasa, kuna kitu

1990
01:39:25,420 --> 01:39:27,510
kwa kuwa alisema kwa
readability ya kanuni hii.

1991
01:39:27,510 --> 01:39:30,690
I mean, kamwe akili na ukweli kwamba hii
code ni mpya kwa wengi wetu katika chumba hicho.

1992
01:39:30,690 --> 01:39:33,515
>> Lakini ni aina tu ya ni pretty.

1993
01:39:33,515 --> 01:39:37,760
Unaweza kuona lowercase y, mji mkuu Y,
chini kesi n, mji mkuu wa N msingi,

1994
01:39:37,760 --> 01:39:40,150
ni aina tu ya anaruka
nje saa wewe kwa njia

1995
01:39:40,150 --> 01:39:42,200
kwamba, arguably, labda
mfano uliopita

1996
01:39:42,200 --> 01:39:45,780
na ikiwa na baa wima,
na mwingine ikiwa, wanaweza kuwa na.

1997
01:39:45,780 --> 01:39:51,600
Hivyo hii ni kweli suala la binafsi
uchaguzi, kwa kweli, au readability,

1998
01:39:51,600 --> 01:39:52,360
ya kanuni.

1999
01:39:52,360 --> 01:39:58,230
>> Lakini katika suala la utendaji, napenda
kwenda mbele na kufanya kubadili, dot kufyeka

2000
01:39:58,230 --> 01:40:05,830
kubadili, na sasa aina katika lowercase y,
mji mkuu Y, lowercase n, mji mkuu wa N,

2001
01:40:05,830 --> 01:40:09,250
David, jaribu kwa sababu hiyo ni
si tabia moja.

2002
01:40:09,250 --> 01:40:12,050
Hebu kufanya x, kosa, kama ilivyotarajiwa.

2003
01:40:12,050 --> 01:40:15,640
Na, logically-- na hili ni jambo
Napenda kuwatia moyo katika general-- hata

2004
01:40:15,640 --> 01:40:17,790
ingawa tuko tu scratching
uso wa baadhi ya makala haya.

2005
01:40:17,790 --> 01:40:20,560
>> Na wanaweza kuwa dhahiri wakati
mwenyewe kukaa chini katika keyboard,

2006
01:40:20,560 --> 01:40:21,370
jinsi gani kazi hii?

2007
01:40:21,370 --> 01:40:22,240
Kitu gani hii nini?

2008
01:40:22,240 --> 01:40:25,630
jambo zuri juu ya kuwa
mbali, au desktop, au kupata

2009
01:40:25,630 --> 01:40:29,290
kompyuta na compiler,
na pamoja na mhariri wa kanuni kama hii,

2010
01:40:29,290 --> 01:40:32,990
ni unaweza karibu kila mara kujibu hizi
maswali kwa ajili yako mwenyewe tu kwa kujaribu.

2011
01:40:32,990 --> 01:40:36,570
>> Kwa mfano, kama kejeli
swali katika mkono walikuwa,

2012
01:40:36,570 --> 01:40:39,540
kile kinachotokea kama wewe kusahau
mapumziko yako kauli?

2013
01:40:39,540 --> 01:40:41,400
Ambayo ni kweli
kawaida sana kitu cha kufanya,

2014
01:40:41,400 --> 01:40:43,540
kwa sababu haina kuangalia
kama kweli wanahitaji yao.

2015
01:40:43,540 --> 01:40:46,790
Wao si kweli kukamilisha yako
walidhani kama mabano au curly

2016
01:40:46,790 --> 01:40:47,714
brace gani.

2017
01:40:47,714 --> 01:40:49,630
Hebu kwenda mbele na
recompile kificho na kuona.

2018
01:40:49,630 --> 01:40:53,690
Hivyo kufanya kubadili, dot kufyeka kubadili.

2019
01:40:53,690 --> 01:40:56,435
Hebu aina katika kesi ya chini
y, kesi juu, kuingia.

2020
01:40:56,435 --> 01:40:59,390

2021
01:40:59,390 --> 01:41:00,700
Hivyo mimi niliandika y.

2022
01:41:00,700 --> 01:41:04,420
>> Mpango alisema ndiyo, hapana, makosa,
kana kwamba alikuwa kubadilisha mawazo yake.

2023
01:41:04,420 --> 01:41:09,280
Lakini ni aina ya mara, kwa sababu kile kinachotokea
pamoja na kubadili ni kesi ya kwanza kwamba

2024
01:41:09,280 --> 01:41:13,899
mechi yana maana, hey kompyuta,
kutekeleza yote ya maadili ya chini yake.

2025
01:41:13,899 --> 01:41:16,690
Na kama huna kusema mapumziko, au
usiseme mapumziko, au usiseme mapumziko,

2026
01:41:16,690 --> 01:41:19,540
kompyuta ni kwenda pigo
kwa njia zote za wale mistari

2027
01:41:19,540 --> 01:41:22,779
na kutekeleza wote mpaka
anapata kwa kuwa brace curly.

2028
01:41:22,779 --> 01:41:24,320
Hivyo breki ni, kwa kweli, ni lazima.

2029
01:41:24,320 --> 01:41:27,120
Lakini takeaway hapa ni kwamba, wakati
katika shaka, kujaribu kitu.

2030
01:41:27,120 --> 01:41:29,510
Labda kuokoa code yako ya kwanza,
au kuokoa ni katika faili ya ziada

2031
01:41:29,510 --> 01:41:32,930
kama wewe ni kweli wasiwasi kuhusu
messing up na kuwa na kupona

2032
01:41:32,930 --> 01:41:34,430
kazi kwamba unajua ni kazi.

2033
01:41:34,430 --> 01:41:35,410
>> Lakini kujaribu mambo.

2034
01:41:35,410 --> 01:41:38,074
Na wala kuwa na hofu kama, pengine,
ya kile kompyuta anaweza kufanya,

2035
01:41:38,074 --> 01:41:39,490
au kwamba unaweza kuvunja kitu.

2036
01:41:39,490 --> 01:41:42,790
Daima unaweza revert nyuma
kwa baadhi toleo la awali.

2037
01:41:42,790 --> 01:41:45,640
>> Hivyo hebu mwisho kwa kuangalia
katika mpango wa kanuni.

2038
01:41:45,640 --> 01:41:49,020
Tuna uwezo huu sasa kuandika
masharti, na kuandika loops,

2039
01:41:49,020 --> 01:41:50,850
na vigezo, na kazi ya wito.

2040
01:41:50,850 --> 01:41:54,590
Hivyo, kusema ukweli, sisi ni aina ya nyuma katika
ambapo tulikuwa wiki iliyopita na Scratch,

2041
01:41:54,590 --> 01:42:00,120
angalau kwa textual chini ya kulazimisha
mazingira kuliko Scratch inaruhusu.

2042
01:42:00,120 --> 01:42:03,990
>> Lakini taarifa jinsi ya haraka tumekuwa alipewa
kwamba msamiati, hata kama ni

2043
01:42:03,990 --> 01:42:07,570
kwenda kuchukua muda kidogo kuzama katika,
ili tuweze sasa unaweza kutumia msamiati huu

2044
01:42:07,570 --> 01:42:10,320
kuandika programu ya kuvutia zaidi.

2045
01:42:10,320 --> 01:42:12,940
Na hebu kuchukua mtoto hatua
kuelekea kwamba, kama ifuatavyo.

2046
01:42:12,940 --> 01:42:14,890
Hebu kwenda mbele na
kuunda faili mpya hapa.

2047
01:42:14,890 --> 01:42:17,750
>> Mimi nina kwenda kuwaita hii
prototype.c, na kuanzisha

2048
01:42:17,750 --> 01:42:20,954
kwa mara ya kwanza, uwezo
kufanya kazi yako mwenyewe.

2049
01:42:20,954 --> 01:42:22,870
Baadhi ya unaweza kuwa
amefanya kwa Scratch,

2050
01:42:22,870 --> 01:42:25,430
ambapo unaweza kuunda yako
vitalu mwenyewe desturi katika Scratch,

2051
01:42:25,430 --> 01:42:27,892
na kisha Drag yao katika nafasi
popote Ningependa katika C.

2052
01:42:27,892 --> 01:42:30,100
Na katika zaidi ya programu
lugha, unaweza kufanya hasa

2053
01:42:30,100 --> 01:42:33,580
that-- kufanya kazi yako mwenyewe,
kama hawana tayari zipo.

2054
01:42:33,580 --> 01:42:38,660
>> Hivyo, kwa mfano, basi mimi kwenda mbele
na ni pamoja na CS50.h, na ni pamoja na

2055
01:42:38,660 --> 01:42:43,110
kiwango io.h, int kuu utupu.

2056
01:42:43,110 --> 01:42:46,020
Na sasa tuna
placeholder tayari kwenda.

2057
01:42:46,020 --> 01:42:48,550
Mimi kushika uchapishaji mambo
kama majina ya watu leo.

2058
01:42:48,550 --> 01:42:51,910
Na kwamba anahisi like--
bila kuwa nzuri kama kuna

2059
01:42:51,910 --> 01:42:53,936
walikuwa kazi kuitwa magazeti jina?

2060
01:42:53,936 --> 01:42:55,060
Sina kutumia printf.

2061
01:42:55,060 --> 01:42:56,976
Sina kukumbuka
namba zote format.

2062
01:42:56,976 --> 01:43:00,050
Kwa nini si mimi, au kwa nini
hakuwa mtu mbele yangu,

2063
01:43:00,050 --> 01:43:02,980
kujenga kazi kuitwa magazeti
jina, kuwa kutokana na baadhi jina,

2064
01:43:02,980 --> 01:43:03,980
tu Prints nje?

2065
01:43:03,980 --> 01:43:08,700
>> Kwa maneno mengine, kama mimi kusema, hey,
kompyuta, nipe kamba

2066
01:43:08,700 --> 01:43:11,870
kwa kuuliza user kwa vile,
kupitia CS50 ya kupata kamba kazi.

2067
01:43:11,870 --> 01:43:15,090
Hey, kompyuta, kuweka kwamba kamba katika
kutofautiana katika upande wa kushoto,

2068
01:43:15,090 --> 01:43:16,150
na kuiita s.

2069
01:43:16,150 --> 01:43:22,150
Na kisha, hey kompyuta, kwenda mbele
na magazeti kwamba jina la mtu, kufanyika.

2070
01:43:22,150 --> 01:43:26,240
>> Sasa, itakuwa nzuri, kwa sababu
mpango huu, aptly aitwaye,

2071
01:43:26,240 --> 01:43:29,170
inaniambia nini ni zinatakiwa kufanya
kwa njia ya majina hayo kazi ya.

2072
01:43:29,170 --> 01:43:32,930
Hebu kwenda na kufanya mfano, kuingia.

2073
01:43:32,930 --> 01:43:34,930
Na, kwa bahati mbaya,
hii si kwenda kuruka.

2074
01:43:34,930 --> 01:43:39,430
>> Prototype.c, line 7, tabia ya
5, kosa, thabiti tamko

2075
01:43:39,430 --> 01:43:42,960
ya magazeti kazi jina
ni batili katika C99, C99

2076
01:43:42,960 --> 01:43:45,130
maana toleo la C
waliotoka mwaka 1999.

2077
01:43:45,130 --> 01:43:45,730
Ni hayo tu.

2078
01:43:45,730 --> 01:43:48,780
>> Hivyo mimi sijui nini
yote haya ina maana bado.

2079
01:43:48,780 --> 01:43:50,810
Lakini mimi kutambua makosa katika nyekundu.

2080
01:43:50,810 --> 01:43:51,770
Hiyo ni pretty dhahiri.

2081
01:43:51,770 --> 01:43:53,769
>> Na inaonekana kwamba kwa
tabia ya kijani hapa,

2082
01:43:53,769 --> 01:43:57,520
Suala hili ni pamoja na jina magazeti, wazi
paren s, karibu paren, nusu koloni.

2083
01:43:57,520 --> 01:44:01,800
Lakini thabiti tamko la
kazi tulivyofanya angalia kwa ufupi mapema.

2084
01:44:01,800 --> 01:44:04,880
Hii ina maana, tu, kwamba Clang
hajui nini namaanisha.

2085
01:44:04,880 --> 01:44:09,000
>> Nimekuwa kutumika msamiati neno kwamba ni
kamwe kuona au kufundishwa kabla.

2086
01:44:09,000 --> 01:44:11,950
Na hivyo mimi haja ya kufundisha
nini kazi hii maana yake.

2087
01:44:11,950 --> 01:44:13,590
Hivyo mimi nina kwenda mbele na kufanya hivyo.

2088
01:44:13,590 --> 01:44:17,970
>> Mimi nina kwenda mbele na kutekeleza
kazi yangu mwenyewe iitwayo Jina Print.

2089
01:44:17,970 --> 01:44:24,720
Na mimi nina kwenda kusema, kama ifuatavyo, kwamba
ni gani hii, printf, hello, asilimia

2090
01:44:24,720 --> 01:44:27,760
s, backslash n, jina, nusu koloni.

2091
01:44:27,760 --> 01:44:29,250
Hivyo nini mimi tu kufanya?

2092
01:44:29,250 --> 01:44:31,325
>> Hivyo ni zamu nje, kwa
kutekeleza kazi yako mwenyewe,

2093
01:44:31,325 --> 01:44:33,845
sisi aina ya kukopa baadhi ya
muundo huo kama kuu

2094
01:44:33,845 --> 01:44:35,720
kwamba tumekuwa tu imekuwa
kuchukuliwa kwa nafasi, na mimi

2095
01:44:35,720 --> 01:44:37,730
kujua tu kuiga na
kubandika pretty kiasi gani

2096
01:44:37,730 --> 01:44:39,170
Nimekuwa kuandika huko nyuma.

2097
01:44:39,170 --> 01:44:40,570
Lakini taarifa mfano hapa.

2098
01:44:40,570 --> 01:44:43,750
Int, Kuu, Void, tutaweza tease mbali
kabla ya muda mrefu nini kwamba kweli maana yake.

2099
01:44:43,750 --> 01:44:46,160
>> Lakini kwa leo, tu
taarifa parallelism.

2100
01:44:46,160 --> 01:44:48,210
Batili, magazeti jina,
kamba jina, hivyo kuna

2101
01:44:48,210 --> 01:44:50,310
zambarau keyword, ambayo
tunakwenda kuanza

2102
01:44:50,310 --> 01:44:54,067
wito aina ya kurudi, jina la
kazi, na kisha pembejeo.

2103
01:44:54,067 --> 01:44:56,400
Hivyo, kwa kweli, tunaweza distill
aina hii ya kama wiki iliyopita

2104
01:44:56,400 --> 01:44:59,030
kama, hii ni jina au
algorithm ya kificho tuko

2105
01:44:59,030 --> 01:45:00,761
kwenda write--
algorithm msingi

2106
01:45:00,761 --> 01:45:02,010
kificho tunakwenda kuandika.

2107
01:45:02,010 --> 01:45:03,180
>> Hii ni mchango wake.

2108
01:45:03,180 --> 01:45:04,670
Hii ni matokeo yake.

2109
01:45:04,670 --> 01:45:08,730
Kazi hii, magazeti jina, ni
iliyoundwa na kuchukua kamba kuitwa jina,

2110
01:45:08,730 --> 01:45:11,350
au chochote, kama pembejeo, na kisha utupu.

2111
01:45:11,350 --> 01:45:13,904
Ni haina kurudi kitu chochote,
kama kupata kamba au kupata int gani.

2112
01:45:13,904 --> 01:45:15,570
Hivyo ni kwenda kwa mkono mimi kitu nyuma.

2113
01:45:15,570 --> 01:45:17,960
Ni kwenda tu kuwa na
athari upande, hivyo kusema,

2114
01:45:17,960 --> 01:45:19,570
ya uchapishaji jina la mtu.

2115
01:45:19,570 --> 01:45:22,260
Hivyo taarifa, line 7, mimi
wanaweza kupiga jina magazeti.

2116
01:45:22,260 --> 01:45:25,920
Mstari 10, siwezi kufafanua
au kutekeleza jina magazeti.

2117
01:45:25,920 --> 01:45:28,450
Lakini, kwa bahati mbaya, hiyo haitoshi.

2118
01:45:28,450 --> 01:45:31,230
>> Hebu kwenda mbele na
recompile hii baada ya kuokoa.

2119
01:45:31,230 --> 01:45:33,910
Whoa, sasa, nimekuwa alifanya hivyo
mbaya, inaweza kuonekana.

2120
01:45:33,910 --> 01:45:37,027
Hivyo thabiti tamko la
magazeti kazi jina ni batili.

2121
01:45:37,027 --> 01:45:38,360
Na, tena, kuna makosa zaidi.

2122
01:45:38,360 --> 01:45:41,430
Lakini kama mimi alionya mapema, hata
kama wewe kupata kuzidiwa na,

2123
01:45:41,430 --> 01:45:44,850
au huzuni kidogo kuona hivyo wengi
makosa, lengo tu juu ya kwanza

2124
01:45:44,850 --> 01:45:47,500
awali, kwa sababu ili tu
wamekuwa na kuachia athari.

2125
01:45:47,500 --> 01:45:51,970
Hivyo C, au Clang zaidi hasa,
bado haitambui jina magazeti.

2126
01:45:51,970 --> 01:45:54,580
>> Na kwamba kwa sababu Clang,
kwa kubuni, ni aina ya bubu.

2127
01:45:54,580 --> 01:45:56,280
Ni tu haina nini kuwaambia ni kufanya.

2128
01:45:56,280 --> 01:46:00,950
Na ni tu anafanya hivyo ili
ambayo wewe kuwaambia ni kufanya.

2129
01:46:00,950 --> 01:46:05,270
>> Hivyo mimi kuwa defined kuu kwenye mstari nne,
kama tumekuwa kufanya pretty mara kwa mara.

2130
01:46:05,270 --> 01:46:07,980
Nimekuwa inavyoelezwa jina magazeti kwenye mstari 10.

2131
01:46:07,980 --> 01:46:11,793
Lakini mimi nina kujaribu kutumia
magazeti jina kwenye mstari saba.

2132
01:46:11,793 --> 01:46:13,670
>> Ni mapema mno, haipo bado.

2133
01:46:13,670 --> 01:46:19,150
Ili niweze kuwa wajanja, na kuwa kama,
OK, hivyo hebu tu kucheza pamoja,

2134
01:46:19,150 --> 01:46:23,680
na hoja jina magazeti up
hapa, na re-kukusanya.

2135
01:46:23,680 --> 01:46:24,550
Mungu wangu.

2136
01:46:24,550 --> 01:46:25,260
Ni kazi.

2137
01:46:25,260 --> 01:46:26,670
Ilikuwa ni rahisi kama hayo.

2138
01:46:26,670 --> 01:46:28,120
>> Lakini mantiki ni hasa kwamba.

2139
01:46:28,120 --> 01:46:30,870
Una kufundisha Clang nini
ni kwa kufafanua kazi ya kwanza.

2140
01:46:30,870 --> 01:46:31,920
Basi unaweza kuitumia.

2141
01:46:31,920 --> 01:46:33,940
Lakini, kusema ukweli, hii anahisi
kama slippery slope.

2142
01:46:33,940 --> 01:46:35,773
>> Hivyo kila wakati mimi kukimbia
katika tatizo, mimi nina tu

2143
01:46:35,773 --> 01:46:39,450
kwenda kuonyesha na nakala ya kanuni
Niliandika, ukate na kuweka it up hapa.

2144
01:46:39,450 --> 01:46:41,370
Na hakika tunaweza
uliamua baadhi ya matukio

2145
01:46:41,370 --> 01:46:43,286
ambapo kazi mtu anaweza
haja ya simu jingine.

2146
01:46:43,286 --> 01:46:46,030
Na wewe tu hawezi kuweka kila
kazi juu ya kila mmoja.

2147
01:46:46,030 --> 01:46:47,930
>> Hivyo ni zamu nje kuna ya
ufumbuzi bora.

2148
01:46:47,930 --> 01:46:50,100
Tunaweza kuondoka iwe hivyo.

2149
01:46:50,100 --> 01:46:53,677
Na, kusema ukweli, ni kwa ujumla nzuri,
na urahisi, na kubuni nzuri

2150
01:46:53,677 --> 01:46:56,760
kuweka kuu ya kwanza, kwa sababu, tena,
kuu tu kama wakati kijani bendera clicked,

2151
01:46:56,760 --> 01:46:59,027
kwamba ni kazi ambayo
anapata kunyongwa na default.

2152
01:46:59,027 --> 01:47:01,110
Hivyo unaweza pia kuweka
hivyo wakati juu ya faili

2153
01:47:01,110 --> 01:47:03,560
hivyo kwamba wakati wewe au yoyote
binadamu wengine inaangalia faili

2154
01:47:03,560 --> 01:47:06,360
unajua nini kinaendelea
tu kwa kusoma kuu ya kwanza.

2155
01:47:06,360 --> 01:47:15,360
Hivyo ni zamu nje, tunaweza kujua Clang
proactively, hey, Clang, kwenye mstari nne,

2156
01:47:15,360 --> 01:47:17,940
Mimi ahadi ya kutekeleza
kazi kuitwa Print

2157
01:47:17,940 --> 01:47:22,600
Jina kwamba inachukua kamba kuitwa jina
kama pembejeo, na anarudi kitu, utupu.

2158
01:47:22,600 --> 01:47:24,770
Na mimi itabidi kupata karibu na
kutekeleza hayo baadaye.

2159
01:47:24,770 --> 01:47:25,680
>> Hiyo inakuja Kuu.

2160
01:47:25,680 --> 01:47:29,130
Kuu sasa kwenye mstari 9 wanaweza kutumia
Jina Print kwa sababu Clang

2161
01:47:29,130 --> 01:47:32,600
ni kuamini kwamba, hatimaye,
itakuwa kukutana ufafanuzi

2162
01:47:32,600 --> 01:47:34,880
ya utekelezaji wa Jina Print.

2163
01:47:34,880 --> 01:47:37,390
Kwa hiyo baada ya kuokoa faili yangu, hebu
mimi kwenda mbele na kufanya mfano,

2164
01:47:37,390 --> 01:47:38,498
inaonekana ni nzuri wakati huu.

2165
01:47:38,498 --> 01:47:43,470
Dot kufyeka, mfano, napenda
kwenda mbele na aina katika jina.

2166
01:47:43,470 --> 01:47:48,440
David, hello David, Zamila, hello
Zamila, na kwa kweli, sasa ni kazi.

2167
01:47:48,440 --> 01:47:52,200
>> Hivyo kingo hapa ni kwamba tumekuwa
alifanya kazi desturi, kama desturi

2168
01:47:52,200 --> 01:47:54,219
Scratch kuzuia sisi ni wito yake.

2169
01:47:54,219 --> 01:47:57,010
Lakini tofauti na Scratch ambapo unaweza
tu kujenga ni na kuanza kutumia,

2170
01:47:57,010 --> 01:47:59,330
sasa sisi kuwa
kidogo zaidi pedantic,

2171
01:47:59,330 --> 01:48:03,410
na kwa kweli mafunzo Clang
kutumia, au kwa kutarajia.

2172
01:48:03,410 --> 01:48:09,140
Sasa, kama kando, kwa nini muda wote huu na
sisi wamekuwa tu upofu juu ya imani ikiwa ni pamoja na

2173
01:48:09,140 --> 01:48:12,170
CS50.h, na ikiwa ni pamoja na kiwango io.h?

2174
01:48:12,170 --> 01:48:15,190
>> Naam, ni zamu nje,
miongoni mwa mambo mengine machache,

2175
01:48:15,190 --> 01:48:18,550
yote yale ambayo ni katika wale dot h
files, ambayo kutokea kwa kuwa mafaili.

2176
01:48:18,550 --> 01:48:20,460
Wao ni header files, hivyo kusema.

2177
01:48:20,460 --> 01:48:23,270
Wao bado uko kuandikwa katika C. Lakini
wao uko aina tofauti ya file.

2178
01:48:23,270 --> 01:48:28,690
>> Kwa sasa, unaweza pretty much kudhani
ambazo vitu vyote vilivyomo ndani ya CS50.h

2179
01:48:28,690 --> 01:48:33,360
baadhi ya moja-liners kama hii, si
kwa ajili ya kazi inaitwa Jina Print,

2180
01:48:33,360 --> 01:48:36,840
lakini kwa Kupata Kamba, Kupata
Float, na wengine wachache.

2181
01:48:36,840 --> 01:48:41,510
Na kuna prototypes sawa,
moja liners, ndani ya kiwango io.h

2182
01:48:41,510 --> 01:48:46,241
kwa printf, ambayo sasa ni katika
yangu mwenyewe Jina Print kazi.

2183
01:48:46,241 --> 01:48:49,490
Hivyo kwa maneno mengine, wakati huu mzima tumekuwa
tu imekuwa upofu kuiga na pasting

2184
01:48:49,490 --> 01:48:51,780
pamoja na hii, ni pamoja na
kwamba, nini kinaendelea?

2185
01:48:51,780 --> 01:48:55,310
Hayo ni tu aina ya dalili
kwa Clang kama kwa kazi gani

2186
01:48:55,310 --> 01:49:00,170
ni kweli, kutekelezwa, tu
mahali pengine katika mafaili mbalimbali

2187
01:49:00,170 --> 01:49:02,440
mahali pengine katika mfumo.

2188
01:49:02,440 --> 01:49:05,160
>> Hivyo tumekuwa kutekelezwa jina magazeti.

2189
01:49:05,160 --> 01:49:07,910
Ni gani kuwa athari hii upande wa
uchapishaji kitu juu ya screen.

2190
01:49:07,910 --> 01:49:10,170
Lakini haina kweli
mkono mimi kitu nyuma.

2191
01:49:10,170 --> 01:49:12,200
Jinsi gani sisi kwenda juu
utekelezaji wa mpango huo

2192
01:49:12,200 --> 01:49:14,510
haina mkono mimi kitu nyuma?

2193
01:49:14,510 --> 01:49:15,580
>> Naam, hebu jaribu hii.

2194
01:49:15,580 --> 01:49:21,360
Hebu kwenda mbele na kutekeleza
faili inayoitwa return.c

2195
01:49:21,360 --> 01:49:24,530
ili tuweze kuonyesha jinsi kitu
kama Kupata Kamba, au Kupata Int,

2196
01:49:24,530 --> 01:49:27,340
ni kweli kurudi
kitu nyuma kwa mtumiaji.

2197
01:49:27,340 --> 01:49:29,840
Hebu kwenda mbele na kufafanua int kuu utupu.

2198
01:49:29,840 --> 01:49:33,230
>> Na tena, katika siku zijazo, tutaweza
kueleza kile kwamba int na kwamba utupu

2199
01:49:33,230 --> 01:49:34,090
ni kweli kufanya.

2200
01:49:34,090 --> 01:49:35,840
Lakini kwa leo, tutaweza
kuchukua ni kwa nafasi.

2201
01:49:35,840 --> 01:49:39,970
Mimi nina kwenda mbele na printf,
kwa nzuri user uzoefu, x ni.

2202
01:49:39,970 --> 01:49:44,360
Na kisha mimi nina kwenda kusubiri kwa
user kunipa x na kupata int.

2203
01:49:44,360 --> 01:49:48,459
>> Na kisha mimi nina kwenda mbele
na magazeti nje x kwa mraba.

2204
01:49:48,459 --> 01:49:50,500
Hivyo wakati wewe tu na
keyboard, watu kawaida

2205
01:49:50,500 --> 01:49:52,600
kutumia karoti kidogo
ishara juu ya keyboard

2206
01:49:52,600 --> 01:49:55,330
kuiwakilisha madarakani
ya, au exponent ya.

2207
01:49:55,330 --> 01:49:58,960
Hivyo x mraba ni sasa i.

2208
01:49:58,960 --> 01:50:00,660
>> Na sasa mimi nina kwenda kufanya hili.

2209
01:50:00,660 --> 01:50:03,940
Mimi naweza do-- tu nini x
squared? x squared ni mara x x.

2210
01:50:03,940 --> 01:50:06,690
>> Na sisi alifanya hivyo baadhi
wakati uliopita tayari leo.

2211
01:50:06,690 --> 01:50:08,730
Hii haina kujisikia kama
zote kuwa maendeleo makubwa.

2212
01:50:08,730 --> 01:50:09,570
Unajua nini?

2213
01:50:09,570 --> 01:50:13,100
Hebu kujiinua baadhi ya wazo kwamba
mara ya mwisho ya kufikirika tu.

2214
01:50:13,100 --> 01:50:16,080
>> Je, si ni kuwa nzuri kama
kuna kazi kuitwa

2215
01:50:16,080 --> 01:50:18,460
mraba kwamba gani hasa kwamba?

2216
01:50:18,460 --> 01:50:20,640
Bado, mwishoni mwa
siku, je math sawa.

2217
01:50:20,640 --> 01:50:22,410
Lakini hebu abstract
mbali wazo la kuchukua

2218
01:50:22,410 --> 01:50:25,280
namba moja tele na
mwingine, na tu kuwapa jina,

2219
01:50:25,280 --> 01:50:27,360
kama mraba thamani hii.

2220
01:50:27,360 --> 01:50:29,560
>> Na, kwa maneno mengine, katika
C, hebu kujenga kazi

2221
01:50:29,560 --> 01:50:32,660
aitwaye mraba kwamba gani hasa kwamba.

2222
01:50:32,660 --> 01:50:34,600
Ni kwenda kuitwa mraba.

2223
01:50:34,600 --> 01:50:35,790
Ni kwenda kuchukua int.

2224
01:50:35,790 --> 01:50:37,820
Na tutaweza mapenzi tu
kuiita n, na default.

2225
01:50:37,820 --> 01:50:39,403
>> Lakini tunaweza kuiita chochote tunataka.

2226
01:50:39,403 --> 01:50:42,900
Na yote ni kwenda
kufanya, literally, ni kurudi

2227
01:50:42,900 --> 01:50:45,810
matokeo ya nyakati n n.

2228
01:50:45,810 --> 01:50:48,980
Lakini kwa sababu ni
kurudisha kitu, ambayo

2229
01:50:48,980 --> 01:50:53,690
ni keyword katika zambarau tumekuwa
kamwe kuona mbele, I, kwenye mstari 11,

2230
01:50:53,690 --> 01:50:55,410
Huwezi tu kusema utupu wakati huu.

2231
01:50:55,410 --> 01:51:01,320
>> Batili, katika mfano sisi tu kuona
badala ya jina magazeti, tu ina maana,

2232
01:51:01,320 --> 01:51:02,190
fanya kitu.

2233
01:51:02,190 --> 01:51:04,170
Lakini si mkono mimi kitu nyuma.

2234
01:51:04,170 --> 01:51:06,790
Katika kesi hiyo, mimi nataka
kurudi n mara n,

2235
01:51:06,790 --> 01:51:08,460
au chochote yaani, idadi hiyo.

2236
01:51:08,460 --> 01:51:12,460
>> Hivyo siwezi kusema, hey, kompyuta,
Mimi kurudi kitu, utupu.

2237
01:51:12,460 --> 01:51:16,166
Ni kwenda na kurudi, kwa asili, int.

2238
01:51:16,166 --> 01:51:17,790
Na hivyo ndiyo yote kinaendelea hapa.

2239
01:51:17,790 --> 01:51:20,070
>> pembejeo kwa mraba
ni kwenda kuwa int.

2240
01:51:20,070 --> 01:51:24,760
Na ili tuweze kuitumia, ina
kuwa na jina, N. Ni kwenda pato

2241
01:51:24,760 --> 01:51:26,240
int kwamba haina haja jina.

2242
01:51:26,240 --> 01:51:29,590
Tunaweza kuondoka kwa kuu, au ye yote ni
kutumia mimi kukumbuka thamani hii kama sisi

2243
01:51:29,590 --> 01:51:31,120
wanataka na kutofautiana yake mwenyewe.

2244
01:51:31,120 --> 01:51:33,230
>> Na, tena, mpya tu
keyword hapa ni marejeo.

2245
01:51:33,230 --> 01:51:34,480
Na mimi nina tu kufanya baadhi ya math.

2246
01:51:34,480 --> 01:51:41,825
Kama mimi kwa kweli alitaka kuwa unnecessary,
Mimi naweza kusema int bidhaa anapata n mara n.

2247
01:51:41,825 --> 01:51:44,170
>> Na kisha mimi naweza kusema, kurudi bidhaa.

2248
01:51:44,170 --> 01:51:47,360
Lakini tena, kwa uhakika yangu ya awali ya
hii si tu kuwa design-- nzuri

2249
01:51:47,360 --> 01:51:50,060
kama, kwa nini kuanzisha jina,
ishara, kama bidhaa,

2250
01:51:50,060 --> 01:51:51,570
tu mara moja kurudi yake?

2251
01:51:51,570 --> 01:51:53,670
Ni safi kidogo,
stramare kidogo, hivyo

2252
01:51:53,670 --> 01:51:59,380
kusema, tu kusema mara kurudi n
n, kujikwamua mstari huu kabisa.

2253
01:51:59,380 --> 01:52:02,860
>> Na ni tu chini ya kanuni kusoma,
chini fursa kwa makosa.

2254
01:52:02,860 --> 01:52:05,180
Na hebu angalia kama hii
kweli sasa anafanya kazi.

2255
01:52:05,180 --> 01:52:09,380
Sasa, mimi nina kwenda
mbele na kufanya kurudi.

2256
01:52:09,380 --> 01:52:11,460
>> Uh-oh, thabiti tamko la kazi.

2257
01:52:11,460 --> 01:52:14,080
Mimi alifanya kosa hilo kabla, hakuna mpango mkubwa.

2258
01:52:14,080 --> 01:52:18,950
Napenda tu aina, au kuonyesha na
nakala, exact kazi mfano,

2259
01:52:18,950 --> 01:52:21,342
au saini, ya kazi hapa.

2260
01:52:21,342 --> 01:52:22,800
Au mimi naweza hoja kazi nzima.

2261
01:52:22,800 --> 01:52:23,841
>> Lakini hiyo ni kidogo wavivu.

2262
01:52:23,841 --> 01:52:24,870
Hivyo sisi si kufanya hivyo.

2263
01:52:24,870 --> 01:52:27,960
Sasa, basi mimi kufanya kurudi
tena, dot kufyeka kurudi.

2264
01:52:27,960 --> 01:52:32,790
>> x ni 2. x mraba ni 4.
x ni 3. x mraba ni 9.

2265
01:52:32,790 --> 01:52:35,300
Na kazi inaonekana
sasa kwa kuwa kazi.

2266
01:52:35,300 --> 01:52:36,550
Basi nini tofauti hapa?

2267
01:52:36,550 --> 01:52:42,520
Nina kazi kwamba wito mraba,
katika kesi hii, ambayo mimi kuweka katika pembejeo.

2268
01:52:42,520 --> 01:52:43,830
Na mimi kupata nyuma pato.

2269
01:52:43,830 --> 01:52:46,210
Na bado, hapo awali, ikiwa
Mimi kufungua mfano mwingine

2270
01:52:46,210 --> 01:52:51,640
kutoka mapema, ambayo
Ilikuwa inaitwa prototype.c,

2271
01:52:51,640 --> 01:52:54,770
Mimi nilikuwa magazeti jina, ambayo
akarudi batili, hivyo kusema,

2272
01:52:54,770 --> 01:52:58,730
Au akarudi kitu, na
tu alikuwa athari upande.

2273
01:52:58,730 --> 01:53:00,230
>> Hivyo nini kinaendelea hapa?

2274
01:53:00,230 --> 01:53:03,520
Naam, kufikiria kazi
kupata kamba kwa muda tu.

2275
01:53:03,520 --> 01:53:06,570
Tumekuwa kutumia kazi
kupata kamba kwa njia hii.

2276
01:53:06,570 --> 01:53:10,464
>> Tumekuwa na kazi kupata
kamba, kama ni pamoja na CS50.h,

2277
01:53:10,464 --> 01:53:16,624
pamoja na kiwango io.h, int, kuu, utupu.

2278
01:53:16,624 --> 01:53:18,790
Na kisha kila wakati nimekuwa
aitwaye kupata kamba hivi sasa,

2279
01:53:18,790 --> 01:53:23,260
Nimekuwa alisema kitu kama, kamba s
anapata kupata kamba, kwa sababu get kamba

2280
01:53:23,260 --> 01:53:27,880
hebu simu hii get.c-- kupata kamba
yenyewe anarudi kamba kwamba naweza kisha

2281
01:53:27,880 --> 01:53:32,050
kutumia, na kusema, hello, comma,
asilimia s, backslash n, s.

2282
01:53:32,050 --> 01:53:35,660
>> Hivyo hii ni mfano huo,
kweli, kwamba tulikuwa mapema.

2283
01:53:35,660 --> 01:53:37,920
Hivyo kupata kamba anarudi thamani.

2284
01:53:37,920 --> 01:53:41,260
Lakini wakati iliyopita, kamba magazeti
haina kurudi thamani.

2285
01:53:41,260 --> 01:53:42,721
Ni tu ina athari upande.

2286
01:53:42,721 --> 01:53:44,220
Hivyo hii ni tofauti ya kimsingi.

2287
01:53:44,220 --> 01:53:46,710
Tumeona tofauti
aina ya kazi sasa,

2288
01:53:46,710 --> 01:53:49,490
baadhi ya ambayo wamerejea
maadili, baadhi ya ambayo hawana.

2289
01:53:49,490 --> 01:53:51,890
Hivyo labda ni kamba, au int, au kuelea.

2290
01:53:51,890 --> 01:53:53,480
Au labda ni tu utupu.

2291
01:53:53,480 --> 01:53:55,710
>> Na tofauti ni
kwamba kazi hizi kwamba

2292
01:53:55,710 --> 01:53:59,940
kupata data na kurudi thamani ni kweli
kuleta kitu nyuma ya meza,

2293
01:53:59,940 --> 01:54:01,110
hivyo kusema.

2294
01:54:01,110 --> 01:54:03,710
Basi hebu kwenda mbele na
kuangalia seti moja ya mwisho

2295
01:54:03,710 --> 01:54:09,129
ya mifano kwamba anatoa hisia, sasa, ya
jinsi tunaweza, kwa hakika, abstract bora,

2296
01:54:09,129 --> 01:54:11,670
na bora, na bora, au zaidi,
na zaidi, na zaidi, ili

2297
01:54:11,670 --> 01:54:13,810
kuandika, hatimaye, vizuri kanuni.

2298
01:54:13,810 --> 01:54:16,860
Hebu kwenda mbele, na kwa roho
ya Scratch, kufanya yafuatayo.

2299
01:54:16,860 --> 01:54:21,700
>> Hebu kwenda mbele na ni pamoja na
CS50.h na kiwango io.h.

2300
01:54:21,700 --> 01:54:24,010
Hebu kwenda mbele na kutoa
mwenyewe int, kuu, utupu.

2301
01:54:24,010 --> 01:54:27,380
Na napenda kwenda mbele, piga cough.c hii.

2302
01:54:27,380 --> 01:54:35,510
>> Na napenda kwenda mbele na tu
kama Scratch, magazeti nje kikohozi / n.

2303
01:54:35,510 --> 01:54:37,170
Na mimi nataka kufanya hili mara tatu.

2304
01:54:37,170 --> 01:54:39,670
Hivyo mimi nina, bila shaka, tu kwenda
na nakala na kuweka mara tatu.

2305
01:54:39,670 --> 01:54:46,440
Mimi sasa kwenda kufanya
kikohozi dot kufyeka kikohozi.

2306
01:54:46,440 --> 01:54:50,120
Hebu kutoa mwenyewe kidogo zaidi chumba
hapa, Ingieni, kukohoa, kikohozi, kikohozi.

2307
01:54:50,120 --> 01:54:53,970
>> Kuna, ni wazi, tayari
nafasi ya kuboresha.

2308
01:54:53,970 --> 01:54:55,679
Nimekuwa kunakiliwa na pasted
mara chache leo.

2309
01:54:55,679 --> 01:54:58,261
Lakini hiyo ilikuwa tu hivyo sikuwa
kuwa na aina kama wahusika wengi.

2310
01:54:58,261 --> 01:55:00,250
Mimi bado iliyopita nini
wale mstari wa kanuni ni.

2311
01:55:00,250 --> 01:55:04,240
>> mistari watatu hawa ni kufanana,
ambayo anahisi wavivu na kwa kweli ni,

2312
01:55:04,240 --> 01:55:07,110
na pengine si njia ya haki.

2313
01:55:07,110 --> 01:55:11,029
Hivyo, pamoja na yale kingo
tunaweza kuboresha kanuni hii?

2314
01:55:11,029 --> 01:55:12,570
Hatuna nakala na kuweka kanuni.

2315
01:55:12,570 --> 01:55:15,070
>> Na, kwa hakika, wakati wowote kujisikia
mwenyewe kuiga na pasting,

2316
01:55:15,070 --> 01:55:17,700
na hata kubadilisha kanuni,
ni tabia mbaya kuna njia bora.

2317
01:55:17,700 --> 01:55:19,470
Na, kwa hakika, kuna.

2318
01:55:19,470 --> 01:55:22,510
Hebu kwenda mbele na kufanya kwa kitanzi,
ingawa syntax nguvu si

2319
01:55:22,510 --> 01:55:24,570
kuja kawaida bado.

2320
01:55:24,570 --> 01:55:29,494
>> Je, hii mara tatu, tu
kwa kufanya following--

2321
01:55:29,494 --> 01:55:31,160
na mimi kutokea kwa kujua hii kutoka mazoezi.

2322
01:55:31,160 --> 01:55:32,810
Lakini tuna idadi ya mifano sasa.

2323
01:55:32,810 --> 01:55:34,950
Na utaona online
marejeo zaidi bado.

2324
01:55:34,950 --> 01:55:37,790
>> Hii ni syntax kwenye mstari 6, kwamba
kiasi kama Scratch kwamba kurudia

2325
01:55:37,790 --> 01:55:40,090
kuzuia, kurudia kufuatia mara tatu.

2326
01:55:40,090 --> 01:55:41,340
Ni kichawi kidogo kwa sasa.

2327
01:55:41,340 --> 01:55:43,050
Lakini hii kupata zaidi,
na zaidi ya ukoo.

2328
01:55:43,050 --> 01:55:45,050
>> Na itakuja kurudia
line nane mara tatu,

2329
01:55:45,050 --> 01:55:52,390
ili kwamba kama mimi re-kukusanya kufanya kikohozi,
dot kufyeka kukohoa, kikohozi, kikohozi, kikohozi.

2330
01:55:52,390 --> 01:55:54,030
Bado kazi kwa njia hiyo hiyo.

2331
01:55:54,030 --> 01:55:55,550
Basi hiyo ni yote faini na nzuri.

2332
01:55:55,550 --> 01:55:58,200
Lakini si kwamba yanayotumika sana.

2333
01:55:58,200 --> 01:55:59,371
>> Ni sahihi kabisa.

2334
01:55:59,371 --> 01:56:01,370
Lakini anahisi kama kuna
inaweza kuwa fursa,

2335
01:56:01,370 --> 01:56:03,750
kama katika ulimwengu wa
Scratch, kwa namna ya kuanza

2336
01:56:03,750 --> 01:56:07,530
kuongeza baadhi ya semantiki hapa ili
Mimi si tu kuwa na baadhi ya kwa kitanzi,

2337
01:56:07,530 --> 01:56:09,867
na kazi ambayo anasema
kikohozi, au gani kikohozi.

2338
01:56:09,867 --> 01:56:10,450
Unajua nini?

2339
01:56:10,450 --> 01:56:12,620
Hebu jaribu kuwa
baridi kidogo zaidi ya kwamba,

2340
01:56:12,620 --> 01:56:16,090
na kweli kuandika kazi ambayo
ina baadhi ya madhara, simu yake kikohozi.

2341
01:56:16,090 --> 01:56:20,830
>> Na inachukua hakuna pembejeo, na
anarudi hakuna thamani kama pato.

2342
01:56:20,830 --> 01:56:22,680
Lakini unajua nini ni gani?

2343
01:56:22,680 --> 01:56:29,370
Ni anafanya Haya printf,
quote unquote, kikohozi.

2344
01:56:29,370 --> 01:56:32,380
>> Na sasa hapa, mimi nina kwenda
kwenda mbele na kwa int,

2345
01:56:32,380 --> 01:56:36,070
i anapata sifuri, i chini ya 3, i plus plus.

2346
01:56:36,070 --> 01:56:39,770
Mimi nina kwenda kufanya printf, ambayo ni
arguably utekelezaji kiwango cha chini

2347
01:56:39,770 --> 01:56:40,270
undani.

2348
01:56:40,270 --> 01:56:41,353
Sijali jinsi ya kikohozi.

2349
01:56:41,353 --> 01:56:43,240
Mimi nataka tu kutumia kikohozi kazi.

2350
01:56:43,240 --> 01:56:44,840
Na mimi nina tu kwenda kuwaita kikohozi.

2351
01:56:44,840 --> 01:56:46,204
>> Sasa, taarifa dichotomy.

2352
01:56:46,204 --> 01:56:49,370
Wakati wewe piga kazi, kama huna
unataka kuwapa pembejeo, kabisa faini.

2353
01:56:49,370 --> 01:56:51,780
Tu kufanya wazi Paren, karibu
paren, na wewe ni kosa.

2354
01:56:51,780 --> 01:56:56,271
>> Wakati unaweza kufafanua kazi, au
kutangaza mfano kazi ya,

2355
01:56:56,271 --> 01:56:58,770
kama wewe kujua mapema siyo
kwenda kuchukua hoja yoyote,

2356
01:56:58,770 --> 01:57:01,170
kusema utupu katika mabano wale pale.

2357
01:57:01,170 --> 01:57:05,660
Na kwamba inafanya hakika kwamba wewe
si ajali kuzitumia vibaya.

2358
01:57:05,660 --> 01:57:07,020
Hebu kwenda mbele na kufanya kikohozi.

2359
01:57:07,020 --> 01:57:08,540
Na, bila shaka, nimekuwa alifanya makosa.

2360
01:57:08,540 --> 01:57:10,410
>> Dammit, kuna kuwa
thabiti tamko.

2361
01:57:10,410 --> 01:57:11,325
Lakini hiyo ni faini.

2362
01:57:11,325 --> 01:57:12,590
Ni rahisi kurekebisha.

2363
01:57:12,590 --> 01:57:18,240
Mimi tu haja mfano juu juu
katika faili yangu kuliko mimi nina kweli kutumia.

2364
01:57:18,240 --> 01:57:20,070
>> Hivyo sasa napenda kufanya kikohozi tena, nzuri.

2365
01:57:20,070 --> 01:57:20,790
Sasa, ni kazi.

2366
01:57:20,790 --> 01:57:22,930
Kufanya kukohoa, kikohozi, kikohozi, kikohozi.

2367
01:57:22,930 --> 01:57:25,930
Hivyo unaweza kufikiri kwamba sisi ni kweli
zaidi ya uhandisi tatizo hili.

2368
01:57:25,930 --> 01:57:26,763
Na kwa kweli, sisi ni.

2369
01:57:26,763 --> 01:57:28,870
Hii si nzuri
Mgombea wa mpango

2370
01:57:28,870 --> 01:57:31,930
wakati kwa
refactoring, na kufanya nini

2371
01:57:31,930 --> 01:57:35,645
aitwaye kihierarkia mtengano,
ambapo kuchukua baadhi ya kanuni, na kisha

2372
01:57:35,645 --> 01:57:38,790
aina ya sababu mambo ya nje, hivyo kama
kuhusisha semantiki zaidi kwao,

2373
01:57:38,790 --> 01:57:40,930
na kutumia tena hatimaye muda mrefu.

2374
01:57:40,930 --> 01:57:43,490
Lakini ni kuzuia ujenzi kuelekea
mipango ya kisasa zaidi

2375
01:57:43,490 --> 01:57:45,600
kwamba tutaanza
kuandika kabla ya muda mrefu kwamba

2376
01:57:45,600 --> 01:57:50,090
inaruhusu yetu kuwa na msamiati
na ambayo kwa kuandika vizuri kanuni.

2377
01:57:50,090 --> 01:57:52,920
Na kwa kweli, hebu angalia kama sisi
hawezi kujumlisha hili zaidi.

2378
01:57:52,920 --> 01:57:57,984
>> Inaonekana vilema kidogo kwamba mimi, kuu,
haja ya kuwa na wasiwasi kuhusu darn hii kwa kitanzi,

2379
01:57:57,984 --> 01:57:59,400
na wito kikohozi tena na tena.

2380
01:57:59,400 --> 01:58:03,050
Kwa nini siwezi kuwaambia tu kikohozi,
tafadhali kikohozi mara tatu?

2381
01:58:03,050 --> 01:58:08,170
Kwa maneno mengine, kwa nini hawawezi I just
kutoa pembejeo kwa kikohozi na kufanya hili?

2382
01:58:08,170 --> 01:58:11,270
>> Kwa nini siwezi kusema tu, katika
kikohozi kuu mara tatu.

2383
01:58:11,270 --> 01:58:13,150
Na sasa, hii ni aina ya kichawi.

2384
01:58:13,150 --> 01:58:14,540
Ni iterative sana hapa.

2385
01:58:14,540 --> 01:58:15,940
Na ni, kwa kweli, mtoto hatua.

2386
01:58:15,940 --> 01:58:19,250
>> Lakini tu uwezo wa kusema juu ya
line nane, kukohoa mara tatu,

2387
01:58:19,250 --> 01:58:20,730
ni hivyo zaidi someka tu.

2388
01:58:20,730 --> 01:58:24,210
Na, plus, sina kujua
au huduma jinsi kikohozi ni kutekelezwa.

2389
01:58:24,210 --> 01:58:26,460
Na, kwa hakika, baadaye katika
mrefu na kwa miradi ya mwisho,

2390
01:58:26,460 --> 01:58:29,150
kama wewe kukabiliana na mradi na
classmate au wanafunzi wawili,

2391
01:58:29,150 --> 01:58:32,370
utasikia kutambua kwamba wewe ni kwenda
kuwa na, au unataka, kugawanya kazi.

2392
01:58:32,370 --> 01:58:34,650
>> Na wewe ni kwenda wanataka kuamua
mapema, ambaye ni kwenda kufanya nini,

2393
01:58:34,650 --> 01:58:35,483
na ambayo vipande?

2394
01:58:35,483 --> 01:58:37,520
Na bila kuwa nzuri
kama wewe, kwa mfano,

2395
01:58:37,520 --> 01:58:40,100
kuchukua malipo ya uandishi kuu, kufanyika.

2396
01:58:40,100 --> 01:58:43,470
Na roommate yako, au yako
mpenzi kwa ujumla zaidi,

2397
01:58:43,470 --> 01:58:45,230
inachukua huduma ya utekelezaji kikohozi.

2398
01:58:45,230 --> 01:58:49,540
>> Na mgawanyiko huu, hizi
kuta za uchukuaji,

2399
01:58:49,540 --> 01:58:52,310
au matabaka ya uchukuaji kama
utakuwa, ni super nguvu,

2400
01:58:52,310 --> 01:58:55,480
kwa sababu hasa kwa kubwa,
zaidi programu tata na mifumo,

2401
01:58:55,480 --> 01:59:00,070
inaruhusu watu mbalimbali ili kujenga
mambo pamoja, na hatimaye

2402
01:59:00,070 --> 01:59:02,680
kushona kazi zao pamoja kwa njia hii.

2403
01:59:02,680 --> 01:59:05,332
Lakini, bila shaka, sisi
haja ya sasa kurekebisha kikohozi.

2404
01:59:05,332 --> 01:59:07,290
Sisi haja ya kuwaambia kikohozi
kwamba, hey, unajua nini?

2405
01:59:07,290 --> 01:59:11,230
Wewe ni kwenda haja ya kuchukua
pembejeo hivyo si batili, lakini int na sasa.

2406
01:59:11,230 --> 01:59:15,170
Hebu kwenda mbele na kuweka ndani
kikohozi int. i anapata sifuri.

2407
01:59:15,170 --> 01:59:16,890
>> i ni chini ya mara ngapi.

2408
01:59:16,890 --> 01:59:18,550
Nilisema tatu kabla.

2409
01:59:18,550 --> 01:59:20,420
Lakini si kwamba nini nataka.

2410
01:59:20,420 --> 01:59:25,520
Mimi nataka kikohozi kwa kuwa jumla ya
kusaidia idadi yoyote ya iterations.

2411
01:59:25,520 --> 01:59:28,800
>> Hivyo, kwa hakika, ni n kwamba mimi nataka,
chochote mtumiaji inaniambia.

2412
01:59:28,800 --> 01:59:31,620
Sasa, siwezi kwenda mbele na kusema magazeti kikohozi.

2413
01:59:31,620 --> 01:59:34,750
Na bila kujali idadi
user hupita katika,

2414
01:59:34,750 --> 01:59:36,890
Nami iterate kwamba mara nyingi.

2415
01:59:36,890 --> 01:59:39,160
>> Hivyo mwisho wa siku,
mpango huo ni kufanana.

2416
01:59:39,160 --> 01:59:42,820
Lakini taarifa yote ya mambo haya
inaweza hata kuwa katika faili mwingine.

2417
01:59:42,820 --> 01:59:45,620
Hakika, mimi sijui utafutaji
muda gani printf ni kutekelezwa.

2418
01:59:45,620 --> 01:59:47,980
>> Sijui wakati jinsi kupata
kamba, au kupata int, au kupata kuelea

2419
01:59:47,980 --> 01:59:48,646
zinatekelezwa.

2420
01:59:48,646 --> 01:59:50,930
Na mimi sitaki
kuwaona kwenye screen yangu.

2421
01:59:50,930 --> 01:59:55,320
Kama ilivyo, mimi nina kuanza kuzingatia
mpango wangu, si kazi hizo.

2422
01:59:55,320 --> 01:59:59,070
>> Na hivyo, kwa kweli, kwa haraka kama wewe
kuanza factoring code kama hii nje,

2423
01:59:59,070 --> 02:00:01,397
tunaweza hata hoja kikohozi
kwa faili tofauti?

2424
02:00:01,397 --> 02:00:02,730
Mtu mwingine inaweza kutekeleza.

2425
02:00:02,730 --> 02:00:06,810
Na wewe na mpango wako kuwa
nzuri sana, na someka sana,

2426
02:00:06,810 --> 02:00:10,830
arguably, kwa kweli nne
line mpango pale pale.

2427
02:00:10,830 --> 02:00:13,510
>> Basi hebu kwenda mbele sasa
na kufanya moja zaidi mabadiliko.

2428
02:00:13,510 --> 02:00:16,180
Taarifa kwamba mfano wangu
ina mabadiliko juu juu.

2429
02:00:16,180 --> 02:00:18,390
Hivyo basi mimi kurekebisha kwamba hivyo
Sina kupata yelled saa.

2430
02:00:18,390 --> 02:00:22,580
>> Kufanya kikohozi, napenda kukimbia kikohozi mara moja
zaidi, bado kufanya kitu kimoja.

2431
02:00:22,580 --> 02:00:26,010
Lakini sasa, tuna taarifa
ingredient kwa moja toleo la mwisho.

2432
02:00:26,010 --> 02:00:26,940
Unajua nini?

2433
02:00:26,940 --> 02:00:29,040
Sitaki kukohoa tu, lazima.

2434
02:00:29,040 --> 02:00:30,802
Nataka kuwa na kitu zaidi kwa ujumla.

2435
02:00:30,802 --> 02:00:31,510
Hivyo unajua nini?

2436
02:00:31,510 --> 02:00:32,450
Nataka kufanya hili.

2437
02:00:32,450 --> 02:00:37,140
Nataka kuwa na, kiasi kama Scratch
gani, kuzuia kusema, lakini si tu

2438
02:00:37,140 --> 02:00:38,680
kusema kitu baadhi idadi ya nyakati.

2439
02:00:38,680 --> 02:00:41,510
Nataka kusema kamba maalum sana.

2440
02:00:41,510 --> 02:00:43,850
Na, kwa hiyo, mimi si
unataka kusema tu kikohozi.

2441
02:00:43,850 --> 02:00:47,660
Nataka kusema chochote
kamba ni kupita katika.

2442
02:00:47,660 --> 02:00:49,960
>> Hivyo taarifa, nimekuwa wa jumla
hii ili sasa

2443
02:00:49,960 --> 02:00:53,110
kusema anahisi kama jina nzuri
kwa hili, kama Scratch,

2444
02:00:53,110 --> 02:00:55,530
inachukua hoja mbili, tofauti na Scratch.

2445
02:00:55,530 --> 02:00:56,570
Moja ni kamba.

2446
02:00:56,570 --> 02:00:57,300
Moja ni int.

2447
02:00:57,300 --> 02:00:58,130
>> Na mimi naweza kubadili yao.

2448
02:00:58,130 --> 02:01:00,713
I just aina ya kama wazo la
kusema kamba kwanza, na kisha

2449
02:01:00,713 --> 02:01:01,940
jinsi mara baadaye mingi.

2450
02:01:01,940 --> 02:01:03,970
Utupu maana yake bado
haina kurudi kitu chochote.

2451
02:01:03,970 --> 02:01:06,428
Hizi ni baadhi tu ya Visual upande
madhara, kama na [? Jordan,?]

2452
02:01:06,428 --> 02:01:08,240
matusi na athari upande wa kunguruma.

2453
02:01:08,240 --> 02:01:12,630
Ni bado anafanya mara kitu n,
0 hadi, lakini si sawa na n.

2454
02:01:12,630 --> 02:01:14,540
Hii ina maana n jumla nyakati.

2455
02:01:14,540 --> 02:01:16,540
Na kisha tu magazeti nje
chochote kile kamba ni.

2456
02:01:16,540 --> 02:01:19,060
Hivyo nimekuwa kweli wa jumla
hii mstari wa kanuni.

2457
02:01:19,060 --> 02:01:22,460
Hivyo sasa, jinsi gani mimi kutekeleza
kikohozi kazi?

2458
02:01:22,460 --> 02:01:25,520
>> Siwezi kufanya utupu kikohozi.

2459
02:01:25,520 --> 02:01:28,501
Na mimi bado wanaweza kuchukua katika jinsi
mara nyingi unataka kikohozi.

2460
02:01:28,501 --> 02:01:29,250
Lakini unajua nini?

2461
02:01:29,250 --> 02:01:31,240
Mimi sasa wanaweza Punt kusema.

2462
02:01:31,240 --> 02:01:36,540
>> Siwezi kuwaita kusema kwa
neno kikohozi, kupita katika n.

2463
02:01:36,540 --> 02:01:40,410
Na kama nataka pia kutekeleza,
ajili ya kujifurahisha, sneeze kazi,

2464
02:01:40,410 --> 02:01:42,290
Siwezi kuchafya baadhi idadi ya nyakati.

2465
02:01:42,290 --> 02:01:47,300
Na siwezi kuendelea Reusing n, kwa sababu
taarifa kwamba m kwa mantiki hii au upeo

2466
02:01:47,300 --> 02:01:49,470
tu ipo ndani ya kazi hii.

2467
02:01:49,470 --> 02:01:52,767
>> Na n kwa mantiki hii tu
ipo ndani ya kazi hii hapa.

2468
02:01:52,767 --> 02:01:54,600
Hivyo tutaweza kuja nyuma
masuala haya ya upeo.

2469
02:01:54,600 --> 02:02:01,160
Na hapa, mimi nina kwenda tu kusema,
Achoo, na kisha n mara, nusu koloni.

2470
02:02:01,160 --> 02:02:04,340
>> Na sasa, mimi tu haja ya kukopa
hizi kazi saini hapa.

2471
02:02:04,340 --> 02:02:06,290
Hivyo kikohozi ni sahihi.

2472
02:02:06,290 --> 02:02:10,090
Void sneeze ni sahihi sasa.

2473
02:02:10,090 --> 02:02:12,390
>> Na mimi bado tu haja kusema.

2474
02:02:12,390 --> 02:02:18,990
Hivyo mimi nina kwenda kusema, kusema
kamba s, int n, nusu koloni.

2475
02:02:18,990 --> 02:02:22,010
Hivyo nimekuwa juu-engineered
heck nje ya mpango huu.

2476
02:02:22,010 --> 02:02:23,760
>> Na hii haina
lazima maana hii ni

2477
02:02:23,760 --> 02:02:26,343
nini unapaswa kufanya wakati wa kuandika
hata rahisi ya mipango.

2478
02:02:26,343 --> 02:02:29,280
Kuchukua kitu hiyo ni wazi
kweli rahisi, kwa kweli mfupi,

2479
02:02:29,280 --> 02:02:31,800
na re-kuutekeleza
kutumia kanuni njia sana.

2480
02:02:31,800 --> 02:02:34,560
Lakini utasikia kweli kuona, na katika
wakati kuangalia nyuma juu ya mifano hii,

2481
02:02:34,560 --> 02:02:38,610
na kutambua, oh, wale ni hatua
sisi alichukua kwa kweli kujumlisha,

2482
02:02:38,610 --> 02:02:40,797
na sababu kitu nje,
mpaka mwisho wa siku

2483
02:02:40,797 --> 02:02:42,380
kanuni yangu ni kweli pretty nafuu.

2484
02:02:42,380 --> 02:02:45,960
Kwa sababu kama nataka kikohozi tatu
Mara kisha kuchafya mara tatu,

2485
02:02:45,960 --> 02:02:50,420
Mimi tu kwenda rerun hii,
Mpango kufanya kikohozi, na kukimbia kikohozi.

2486
02:02:50,420 --> 02:02:53,620
Na mimi kuwa mafua tatu
na machemuzi tatu.

2487
02:02:53,620 --> 02:02:55,990
>> Na hivyo hii ni ya msingi
dhana, kama wewe,

2488
02:02:55,990 --> 02:03:00,110
kwa jinsi tupate kwenda juu
kweli kutekeleza mpango huo.

2489
02:03:00,110 --> 02:03:03,220
Lakini hebu tu kuona ni nini sasa
tumekuwa kufanya wote wa wakati huu,

2490
02:03:03,220 --> 02:03:06,940
na kile baadhi ya vipande mwisho
ni nyuma amri hii rahisi.

2491
02:03:06,940 --> 02:03:09,620
Mwisho wa siku, tumekuwa
wamekuwa wakitumia Clang kama compiler yetu.

2492
02:03:09,620 --> 02:03:11,494
Sisi tumekuwa kuandika chanzo
kanuni, kuwabadili

2493
02:03:11,494 --> 02:03:12,820
kupitia Clang katika mashine kanuni.

2494
02:03:12,820 --> 02:03:15,540
>> Na tumekuwa kutumia Tengeneza tu
kuwezesha keystrokes yetu ili

2495
02:03:15,540 --> 02:03:20,740
kwamba hatuna kukumbuka
wale incantations ya Clang yenyewe.

2496
02:03:20,740 --> 02:03:22,640
Lakini ni nini Tengeneza kweli kufanya?

2497
02:03:22,640 --> 02:03:24,750
Na, kwa upande wake, ni nini
Clang kweli kufanya?

2498
02:03:24,750 --> 02:03:28,790
>> Ni zamu nje, ingawa sisi wamerahisisha
majadiliano ya leo kwa kusema,

2499
02:03:28,790 --> 02:03:33,090
wewe kuchukua chanzo kanuni, kuupitisha kama
pembejeo kwa compiler, ambayo inatoa wewe

2500
02:03:33,090 --> 02:03:35,750
pato la mashine
kanuni, zinageuka kuna ya

2501
02:03:35,750 --> 02:03:37,420
hatua chache tofauti ndani ya huko.

2502
02:03:37,420 --> 02:03:41,940
Na kuandaa hutokea kwa kuwa mwavuli
mrefu kwa ajili ya kundi zima la hatua.

2503
02:03:41,940 --> 02:03:43,970
Lakini hebu tu tease
nje hii kweli haraka.

2504
02:03:43,970 --> 02:03:48,070
>> Ni zinageuka kuwa tumekuwa kufanya
mambo zaidi kila wakati mimi kukimbia mpango,

2505
02:03:48,070 --> 02:03:50,990
au kila wakati mimi kukusanya mpango leo.

2506
02:03:50,990 --> 02:03:55,020
Hivyo preprocessing inahusu
Haya chochote katika C mpango,

2507
02:03:55,020 --> 02:03:58,720
kama tutaweza kuona tena na tena,
kwamba huanza na alama hii hash,

2508
02:03:58,720 --> 02:04:03,320
au hashtag ishara hapa, maana yake ni
ni preprocessor agizo.

2509
02:04:03,320 --> 02:04:07,330
Hiyo ina maana, katika kesi hii, hey
kompyuta, kufanya kitu na faili hili

2510
02:04:07,330 --> 02:04:09,430
kabla ya kweli kukusanya kanuni yangu mwenyewe.

2511
02:04:09,430 --> 02:04:15,220
>> Katika kesi hiyo, hash ni pamoja na ni,
kimsingi, njia C ya kusema,

2512
02:04:15,220 --> 02:04:19,325
hey kompyuta, kwenda kupata yaliyomo
ya CS50.h na kuweka yao hapa.

2513
02:04:19,325 --> 02:04:22,170
Hey kompyuta, kwenda kupata
yaliyomo ya kiwango io.h,

2514
02:04:22,170 --> 02:04:24,690
popote kwamba ni juu ya
kuendesha gari kwa bidii, kuweka hapa.

2515
02:04:24,690 --> 02:04:27,390
Hivyo mambo hayo kutokea
kwanza wakati wa preprocessing.

2516
02:04:27,390 --> 02:04:28,880
>> Na Clang gani haya yote kwa ajili yetu.

2517
02:04:28,880 --> 02:04:30,510
Na ni gani hivyo darn
haraka, huna hata

2518
02:04:30,510 --> 02:04:32,000
kuona mambo manne yanatokea.

2519
02:04:32,000 --> 02:04:34,100
Lakini hiyo ni hatua ya kwanza kama hizo.

2520
02:04:34,100 --> 02:04:35,560
>> Ni nini hasa kinatokea ijayo?

2521
02:04:35,560 --> 02:04:38,320
Naam, rasmi ijayo
hatua ni kuandaa.

2522
02:04:38,320 --> 02:04:40,385
Na zinageuka kuwa
kuandaa mpango

2523
02:04:40,385 --> 02:04:44,060
kitaalam maana kwenda kutoka
chanzo kanuni, mambo tumekuwa

2524
02:04:44,060 --> 02:04:47,890
wamekuwa kuandika leo, na kitu
aitwaye mkutano kificho, kitu

2525
02:04:47,890 --> 02:04:49,260
kwamba inaonekana tofauti kidogo.

2526
02:04:49,260 --> 02:04:51,050
>> Na, kwa kweli, tunaweza kuona hii halisi haraka.

2527
02:04:51,050 --> 02:04:53,890
Hebu kweli kwenda katika IDE yangu.

2528
02:04:53,890 --> 02:04:58,050
Hebu kwenda mbele na kufungua hello.c, ambayo
ni mpango wa kwanza sana ambayo sisi

2529
02:04:58,050 --> 02:04:59,120
alianza leo.

2530
02:04:59,120 --> 02:05:04,130
Na napenda kwenda mbele na kukimbia Clang a
tofauti kidogo, Clang-s, hello.c,

2531
02:05:04,130 --> 02:05:07,720
ambayo ni kweli kwenda
nipe hello.s mwingine file.

2532
02:05:07,720 --> 02:05:10,330
>> Na sisi pengine kamwe
tena kuona aina hii ya kificho.

2533
02:05:10,330 --> 02:05:13,030
Kama wewe kuchukua ngazi ya chini
mifumo darasa kama CS61,

2534
02:05:13,030 --> 02:05:14,920
utaona mengi zaidi
wa aina hii ya kificho.

2535
02:05:14,920 --> 02:05:17,020
Lakini hii ni mkutano lugha.

2536
02:05:17,020 --> 02:05:22,050
Hii ni X86 mkutano lugha
kwamba CPU kwamba ni msingi

2537
02:05:22,050 --> 02:05:24,460
CS50 IDE kweli anaelewa.

2538
02:05:24,460 --> 02:05:27,060
>> Na cryptic kama ilivyo
kuangalia, ni kitu

2539
02:05:27,060 --> 02:05:29,180
kompyuta anaelewa pretty vizuri.

2540
02:05:29,180 --> 02:05:30,790
Sub q, hii ni Ondoa.

2541
02:05:30,790 --> 02:05:31,660
Kuna harakati.

2542
02:05:31,660 --> 02:05:35,730
>> Kuna ni wito wa kazi hapa,
x Oring, harakati, kuongeza, pop,

2543
02:05:35,730 --> 02:05:36,430
kurudi.

2544
02:05:36,430 --> 02:05:38,850
Hivyo kuna baadhi sana
maelekezo kiwango cha chini

2545
02:05:38,850 --> 02:05:41,280
kwamba CPUs kuelewa kwamba
Mimi alluded mapema.

2546
02:05:41,280 --> 02:05:43,100
Hiyo ni nini Intel Ndani.

2547
02:05:43,100 --> 02:05:45,030
>> Kuna mifumo ya
zeros na ndio kwamba

2548
02:05:45,030 --> 02:05:51,800
ramani kwa hawa arcanely worded, lakini
kiasi fulani vizuri aitwaye, maelekezo,

2549
02:05:51,800 --> 02:05:52,780
hivyo kusema.

2550
02:05:52,780 --> 02:05:54,780
Hiyo ni nini kinatokea wakati
wewe kukusanya code yako.

2551
02:05:54,780 --> 02:05:58,560
Unaweza kupata mkutano
Lugha nje ya hayo, ambayo

2552
02:05:58,560 --> 02:06:04,680
ina maana Hatua ya tatu ni ya kukusanyika
kwamba mkutano kificho katika, hatimaye,

2553
02:06:04,680 --> 02:06:09,080
mashine code-- zeros na ndio, si
Nakala kwamba sisi tu kuona wakati iliyopita.

2554
02:06:09,080 --> 02:06:13,370
>> Hivyo kabla ya usindikaji gani kwamba kupata
na badala, na mambo mengine kadhaa.

2555
02:06:13,370 --> 02:06:16,430
Kuandaa inachukua chanzo wako
kanuni kutoka C, chanzo kanuni

2556
02:06:16,430 --> 02:06:18,980
kwamba sisi aliandika ya kanisa
kificho kwamba sisi tu akapiga saa.

2557
02:06:18,980 --> 02:06:22,170
Kukusanyika inachukua kwamba mkutano
kificho kwa zeroes na wale

2558
02:06:22,170 --> 02:06:24,680
kwamba CPU kweli mapenzi
kuelewa mwishoni mwa siku.

2559
02:06:24,680 --> 02:06:27,630
Na kuunganisha ni hatua ya mwisho
hiyo ikitokea kwa us-- tena,

2560
02:06:27,630 --> 02:06:29,830
hivyo kufunga hatuna hata
notice-- kwamba anasema,

2561
02:06:29,830 --> 02:06:32,460
hey kompyuta, kuchukua yote ya
zeros na ndio kwamba

2562
02:06:32,460 --> 02:06:36,750
ilitokana na kuandaa kanuni Daudi,
na kazi yake kuu katika kesi hii.

2563
02:06:36,750 --> 02:06:39,160
>> Na hey kompyuta, kwenda kupata
yote ya zeros na ndio

2564
02:06:39,160 --> 02:06:42,180
kwamba wafanyakazi CS50 aliandika
ndani ya maktaba CS50.

2565
02:06:42,180 --> 02:06:43,440
Kuchanganya wale walio katika na Daudi.

2566
02:06:43,440 --> 02:06:46,648
Na hey kompyuta, kwenda kupata zeros zote
na ndio kuwa mtu mwingine ameandika miaka

2567
02:06:46,648 --> 02:06:47,470
iliyopita kwa printf.

2568
02:06:47,470 --> 02:06:49,880
Na kuongeza wale katika
jambo zima, hivyo kwamba tumekuwa

2569
02:06:49,880 --> 02:06:52,870
got zeros yangu na ndio,
zeros CS50 wafanyakazi na ndio,

2570
02:06:52,870 --> 02:06:55,370
printf zeros na ndio,
na kitu kingine chochote sisi ni kutumia.

2571
02:06:55,370 --> 02:07:00,410
>> Wao wote kupata pamoja pamoja katika moja
programu inayoitwa, katika kesi hii, hello.

2572
02:07:00,410 --> 02:07:03,141
Hivyo tangu sasa, sisi tu
kutumia neno kuandaa.

2573
02:07:03,141 --> 02:07:06,390
Na sisi kuchukua nafasi ya kwamba wakati
tunasema, kukusanya mpango wako, maana yake,

2574
02:07:06,390 --> 02:07:08,849
hey kufanya kabla ya usindikaji,
kukusanyika, na kuunganisha.

2575
02:07:08,849 --> 02:07:11,890
Lakini kuna kweli baadhi ya mambo Juicy
kinaendelea huko chini ya Hood.

2576
02:07:11,890 --> 02:07:13,723
Na hasa kama wewe
kupata curious baadhi ya wakati,

2577
02:07:13,723 --> 02:07:15,900
unaweza kuanza poking
karibu katika ngazi hii ya chini.

2578
02:07:15,900 --> 02:07:19,660
Lakini kwa sasa, kutambua kwamba
miongoni mwa takeaways kwa leo

2579
02:07:19,660 --> 02:07:23,420
ni tu kabisa
mwanzo wa mchakato,

2580
02:07:23,420 --> 02:07:26,700
ya kupata starehe na
kitu kama hujambo dunia.

2581
02:07:26,700 --> 02:07:29,575
Hakika, wengi wa nini tulivyofanya leo
hakika si kuzama katika super haraka.

2582
02:07:29,575 --> 02:07:31,491
Na itachukua baadhi
muda, na baadhi ya mazoezi.

2583
02:07:31,491 --> 02:07:33,864
Na ni tabia mbaya, utakuwa kutatua
ya kutaka kugonga keyboard yako

2584
02:07:33,864 --> 02:07:34,780
au yell saa screen.

2585
02:07:34,780 --> 02:07:35,880
Na wote wa hiyo ni sawa.

2586
02:07:35,880 --> 02:07:38,320
Ingawa, pengine jaribu
kufanya hivyo katika maktaba sana.

2587
02:07:38,320 --> 02:07:40,820
>> Na hatimaye, utasikia
kuwa na uwezo ingawa, kuanza

2588
02:07:40,820 --> 02:07:44,580
kuona chati, katika kanuni nzuri
kwamba umefanya imeandikwa na katika makosa

2589
02:07:44,580 --> 02:07:45,370
kwamba kiunda.

2590
02:07:45,370 --> 02:07:48,965
Na mengi kama mchakato wa
kuwa na TF au CA ni kama,

2591
02:07:48,965 --> 02:07:51,590
itabidi kuanza kupata bora na
bora katika kuona chati hizo,

2592
02:07:51,590 --> 02:07:53,774
na kutatua tu yako
matatizo mwenyewe hatimaye.

2593
02:07:53,774 --> 02:07:56,940
Wakati huo huo, kutakuwa na mengi
mmoja wetu kukopesha wewe msaada, na kupata wewe

2594
02:07:56,940 --> 02:07:57,481
kwa njia hii.

2595
02:07:57,481 --> 02:07:59,450
Na katika kuandika-ups
kwa matatizo yote ya

2596
02:07:59,450 --> 02:08:01,366
je kuongozwa kwa njia ya
amri zote za

2597
02:08:01,366 --> 02:08:05,330
kwamba mimi bila ya shaka tunajua kutoka
mazoezi mengi kwa sasa,

2598
02:08:05,330 --> 02:08:07,380
lakini anaweza kuwa flown
juu ya kichwa ya mtu kwa sasa.

2599
02:08:07,380 --> 02:08:08,580
Na kwamba ni kabisa faini.

2600
02:08:08,580 --> 02:08:11,230
>> Lakini, hatimaye, wewe kwenda
kabla ya kuanza kuona chati kuibuka.

2601
02:08:11,230 --> 02:08:14,260
Na mara moja kupata zamani wote wa
maelezo kijinga, kama mabano,

2602
02:08:14,260 --> 02:08:16,710
na curly braces, na nusu colons,
na mambo, kusema ukweli,

2603
02:08:16,710 --> 02:08:19,360
kwamba si wakati wote
kielimu ya kuvutia.

2604
02:08:19,360 --> 02:08:22,690
Na si lengo la
kuchukua darasa wowote utangulizi.

2605
02:08:22,690 --> 02:08:24,410
Ni mawazo kwamba ni kwenda jambo.

2606
02:08:24,410 --> 02:08:26,659
>> Ni tanzi, na
masharti, na kazi,

2607
02:08:26,659 --> 02:08:30,552
na kwa nguvu zaidi uchukuaji,
na factoring wa kanuni,

2608
02:08:30,552 --> 02:08:33,510
na kubuni nzuri, na mema
style, na hatimaye usahihi

2609
02:08:33,510 --> 02:08:37,330
ya kanuni yako, hiyo ni hatimaye
kwenda suala hilo zaidi.

2610
02:08:37,330 --> 02:08:40,925
Hivyo wiki ijayo, sisi kuchukua hizi
mawazo ambayo sisi kwanza kuona katika Scratch

2611
02:08:40,925 --> 02:08:42,800
na sasa kutafsiriwa
C. Na tutaweza kuanza

2612
02:08:42,800 --> 02:08:45,740
kuanzisha ya kwanza ya
kozi ya ulimwengu wa kweli nyanja.

2613
02:08:45,740 --> 02:08:50,140
>> Tutaweza kuzingatia ulimwengu wa usalama,
na hasa zaidi cryptography,

2614
02:08:50,140 --> 02:08:51,980
sanaa ya scrambling habari.

2615
02:08:51,980 --> 02:08:54,000
Na kati ya kwanza
matatizo wewe mwenyewe

2616
02:08:54,000 --> 02:08:56,840
kupata kuandika zaidi
kucheza na baadhi ya syntax

2617
02:08:56,840 --> 02:08:59,880
na kutatua baadhi mantiki
matatizo, hatimaye kabla ya muda mrefu,

2618
02:08:59,880 --> 02:09:03,960
ni kwa kweli kinyang'anyiro, au encrypt,
na hatimaye decrypt habari.

2619
02:09:03,960 --> 02:09:06,470
Na kila kitu ambacho tumefanya
leo, mapenzi haki ya chini

2620
02:09:06,470 --> 02:09:09,190
ngazi ya juu, ni kwenda tu kuruhusu
sisi kuchukua moja, na moja,

2621
02:09:09,190 --> 02:09:13,550
na hatua moja zaidi juu kuelekea
kuandika kanuni ya kuvutia zaidi bado.

2622
02:09:13,550 --> 02:09:15,050
>> Hivyo zaidi juu ya kwamba wiki ijayo.

2623
02:09:15,050 --> 02:09:17,834

2624
02:09:17,834 --> 02:09:18,762
>> [VIDEO avspelning]

2625
02:09:18,762 --> 02:09:19,690

2626
02:09:19,690 --> 02:09:22,006
>> -Nini Unaweza kuniambia kuhusu
mara ya mwisho kumwona?

2627
02:09:22,006 --> 02:09:26,041

2628
02:09:26,041 --> 02:09:27,040
-Nini Naweza kusema, kweli?

2629
02:09:27,040 --> 02:09:30,500

2630
02:09:30,500 --> 02:09:35,340
I mean, ilikuwa ni kama nyingine yoyote
kabla ya uzalishaji mazoezi,

2631
02:09:35,340 --> 02:09:40,510
isipokuwa kulikuwa na kitu alisema
mwishoni sana kwamba kukwama pamoja nami.

2632
02:09:40,510 --> 02:09:44,810

2633
02:09:44,810 --> 02:09:46,640
>> -Hii Ilikuwa CS50.

2634
02:09:46,640 --> 02:09:49,440

2635
02:09:49,440 --> 02:09:52,190
>> -Kwamba Ni kukata kila mtu,
kazi kubwa juu ya mazoezi.

2636
02:09:52,190 --> 02:09:53,070
>> -Kwamba Ya chakula cha mchana?

2637
02:09:53,070 --> 02:09:54,986
>> -Yeah, Wewe na mimi siwezi
kunyakua sandwich katika kidogo.

2638
02:09:54,986 --> 02:09:58,380
Napenda tu kuwahoji na
David kweli haraka.

2639
02:09:58,380 --> 02:09:59,160
Daudi?

2640
02:09:59,160 --> 02:10:01,260
Daudi?

2641
02:10:01,260 --> 02:10:03,110
>> [MWISHO avspelning]