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[Powered by Google Translate] [SEHEMU 5: Chini starehe]

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[Nate Hardison, Chuo Kikuu cha Harvard]

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[Hii ni CS50.] [CS50.TV]

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Hivyo kuwakaribisha nyuma, guys.

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Karibu sehemu ya 5.

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Katika hatua hii, baada ya kumaliza jaribio 0 na wakayaona jinsi umefanya kosa,

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hopefully unajisikia kweli nzuri kwa sababu mimi nilikuwa hisia sana na alama katika sehemu hii.

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Kwa watazamaji wetu online, tulikuwa na wanandoa wa maswali

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kuhusu miwili iliyopita matatizo juu ya kuweka tatizo - au juu ya chemsha bongo, badala.

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Hivyo sisi ni kwenda juu ya wale kweli haraka ili kila mtu anaona kile kilichotokea

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na jinsi ya kwenda kupitia ufumbuzi halisi badala ya kuangalia ufumbuzi yenyewe.

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Sisi ni kwenda kwenda juu ya wanandoa wa mwisho wa matatizo kweli haraka, 32 na 33.

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Tu, tena, ili watazamaji online unaweza kuona hili.

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>> Kama wewe kugeuka kwa tatizo lako 32, ambayo ni kwenye ukurasa wa 13,

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13 nje ya 16, tatizo ni 32 wote kuhusu swaps.

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Ilikuwa wote kuhusu swapping integers mbili.

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Ni tatizo kwamba sisi d wamekwenda juu ya wanandoa wa nyakati katika hotuba.

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Na katika hapa, nini sisi walikuwa kuuliza wewe kufanya ni haraka kumbukumbu kuwaeleza.

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Kujaza katika maadili ya vigezo kama wao ni juu ya stack

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kama code huenda kwa njia ya kazi hii byta.

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Hasa, nini sisi tunataka - I'm kwenda kuweka hii iPad chini -

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hasa, nini sisi tunataka ni mstari huu kuhesabiwa 6 hapa hapa.

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Na ni kuhesabiwa 6 kwa ajili tu contiguity na tatizo uliopita.

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Nini tunataka kufanya ni kuonyesha au studio hali ya kumbukumbu

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kama ni wakati sisi nitafanya hii idadi mstari 6,

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ambayo ni ufanisi kurudi kutoka byta kazi yetu hapa hapa.

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Kama sisi kitabu chini hapa, tumeona kwamba anwani ya kila kitu katika kumbukumbu yalitolewa kwa ajili yetu.

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Hii ni muhimu sana, tutaweza kuja nyuma yake katika muda tu.

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Na kisha chini hapa chini, sisi alikuwa kidogo kumbukumbu mchoro kwamba sisi ni kwenda kwa kutaja.

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I have kweli jambo hili nje kwenye iPad yangu.

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Hivyo nina kwenda kwa Alternate na kurudi kati ya iPad na kanuni hii tu kwa ajili ya kumbukumbu.

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>> Hebu kuanza. Kwanza, hebu kuzingatia michache ya kwanza ya mistari ya haki kuu hapa.

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Kuanza, tunakwenda initialize x na y kwa 1 na 2.

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Hivyo tuna mbili vigezo integer, wao ni wawili kwenda kuwekwa katika stack.

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Sisi ni kwenda kuweka 1 na 2 katika wao.

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Hivyo kama mimi flip juu kwa iPad wangu, hopefully, hebu angalia -

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Apple TV mirroring, na kuna sisi kwenda. Sawa.

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Hivyo kama mimi flip juu kwa iPad wangu,

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Mimi nataka initialize x na y kwa 1 na 2.

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Sisi kufanya hivyo kwa urahisi kabisa kwa kuandika katika kisanduku 1 alama x

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na 2 katika sanduku alama y. Haki rahisi.

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Hivyo sasa hebu kwenda nyuma ya mbali, kuona nini kitatokea.

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Hivyo hii ni mstari unaofuata ambapo mambo kupata gumu.

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Sisi kupita anwani ya x na anuani ya y kama vigezo na b kwa kazi byta.

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anuani ya x na anuani ya y ni mambo ambayo hatuwezi mahesabu

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bila akimaanisha risasi haya anasema haki ya chini hapa.

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Na bahati nzuri, kwanza mbili risasi pointi kutuambia nini hasa majibu ni.

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anuani ya x katika kumbukumbu ni 10, na anuani ya y katika kumbukumbu ni 14.

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Hivyo wale ni maadili ambayo kupata kupita katika kama na b juu juu katika byta kazi yetu.

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Hivyo tena, byte nyuma mchoro wetu, naweza kuandika 10 katika

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na 14 katika b.

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Sasa, hatua hii ni mahali ambapo sisi kuendelea na kubadilishana.

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Hivyo flipping nyuma mbali tena,

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tunaona kwamba njia byta kazi ni mimi kwanza dereference na kuhifadhi matokeo katika TMP.

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Hivyo operator dereference anasema, "Hey Treat yaliyomo ya kutofautiana kama anwani..

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Nenda chochote ni kuhifadhiwa katika anuani hiyo, na mzigo huo. "

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Nini mzigo nje ya kutofautiana ni kwenda kuhifadhiwa katika TMP variable yetu.

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Flipping nyuma iPad.

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Kama sisi kwenda kushughulikia 10, tunajua kwamba anuani 10 ni x varible

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kwa sababu tuliambiwa na kumweka risasi yetu kwamba anuani ya x katika kumbukumbu ni 10.

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Hivyo tunaweza kwenda huko, kupata thamani yake, ambayo ni 1, kama sisi kuona kwenye iPad yetu,

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na mzigo huo katika TMP.

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Tena, hii si maudhui ya mwisho.

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Sisi ni kwenda kutembea kwa njia na tutaweza kupata hali yetu ya mwisho ya mpango mwishoni.

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Lakini sasa hivi, tuna thamani 1 kuhifadhiwa katika TMP.

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>> Na kuna swali haraka zaidi ya hapa.

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[Alexander] Je operator dereference - kwamba ni haki tu nyota mbele ya kutofautiana?

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>> Ndiyo. Hivyo operator dereference, kama sisi flip nyuma mbali wetu mara nyingine tena,

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hii ni nyota haki mbele.

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Katika hali hiyo, ni - wewe kulinganisha kwa operator kuzidisha

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ambayo inahitaji mambo mawili; operator dereference ni operator unary.

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Tu kutumika kwa thamani moja kinyume na operator binary,

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ambapo wewe yanahusu maadili mbili tofauti.

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Hivyo kwamba ni nini kinatokea katika mstari huu.

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Sisi kubeba thamani 1 na kuhifadhiwa ndani ya variable muda wetu integer.

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line ijayo, sisi kuhifadhi yaliyomo ndani ya b -

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au, bali sisi kuhifadhi yaliyomo kwamba b ni akizungumzia katika mahali ambapo ni akizungumzia.

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Kama sisi kuchambua hii kutoka kulia kwenda kushoto, sisi ni kwenda b dereference,

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sisi ni kwenda kushughulikia 14, sisi ni kwenda kwa kunyakua integer kwamba ni huko,

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na kisha sisi ni kwenda kwa anuani ya 10,

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na sisi ni kwenda kutupa matokeo ya dereference wetu wa b katika nafasi hiyo.

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Flipping nyuma iPad wetu, ambapo tunaweza kufanya hii kidogo zaidi halisi,

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inaweza kusaidia kama mimi kuandika idadi ya juu yote ya anwani hapa.

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Hivyo tunajua kwamba katika y, sisi ni katika anuani 14, x ni katika anuani 10.

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Wakati sisi kuanza saa b, sisi dereference b, tunakwenda kunyakua thamani 2.

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Sisi ni kwenda kunyakua thamani hii kwa sababu ya kuwa ni thamani ya kwamba anaishi katika anuani 14.

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Na sisi ni kwenda kuweka katika variable kwamba anaishi katika anuani 10,

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ambayo ni haki pale, sambamba na x wetu kutofautiana.

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Hivyo tunaweza kufanya kidogo ya overwriting hapa

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ambapo sisi kujikwamua 1 yetu na badala yake sisi kuandika 2.

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Basi wote ni vizuri na wema katika dunia, ingawa tumekuwa x overwritten sasa.

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Sisi kuhifadhiwa x wa zamani wa thamani katika TMP variable yetu.

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Hivyo tunaweza kukamilisha byta na line ijayo.

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Flipping nyuma mbali wetu.

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Sasa inabakia kwamba wote ni kuchukua yaliyomo nje ya variable muda wetu integer

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na kuhifadhi katika variable kwamba anaishi katika anuani kwamba b ameshika.

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Hivyo sisi ni kwenda kwa ufanisi b dereference ili kupata variable

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kwamba ni katika anuani kwamba b ana ndani yake,

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na sisi ni kwenda stuff thamani kwamba TMP ameshika ndani yake.

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Flipping nyuma iPad mara moja zaidi.

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Naweza kufuta thamani hii hapa, 2,

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na badala yake tutaweza nakala kulia 1 ndani yake.

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Kisha mstari unaofuata kwamba executes, bila shaka -

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kama sisi flip nyuma mbali - ni hii 6 uhakika,

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ambayo ni hatua ambayo sisi alitaka kuwa na mchoro wetu kabisa kujazwa.

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Hivyo flipping nyuma iPad mara moja zaidi, tu hivyo unaweza kuona mchoro kukamilika,

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unaweza kuona kwamba tuna 10 katika, 14 katika b, 1 katika TMP, 2 katika x, y na 1 katika.

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Je, kuna maswali kuhusu hili?

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Je, hii kufanya zaidi hisia, baada ya kutembea kwa njia hiyo?

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Kufanya chini hisia? Hopefully si. Sawa.

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>> Kuyatumia ni chini sana suala gumu.

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Moja ya guys sisi kazi na ana msemo wa kawaida sana:

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"Ili kuelewa kuyatumia, lazima kwanza tuelewe kuyatumia."

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Ambayo nadhani ni kweli sana. Ni gani kuchukua muda kupata kutumika yake.

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Kuchora kura ya picha, kuchora vielelezo kura ya kumbukumbu kama hii moja ni msaada sana,

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na baada ya kutembea kwa njia ya mfano baada ya mfano baada ya mfano,

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hivyo itabidi kuanza kufanya kidogo zaidi hisia na akili kidogo zaidi na zaidi kidogo akili.

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Hatimaye, siku moja, itabidi yote kabisa mastered.

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Maswali yoyote kabla ya sisi kuondoka na tatizo ijayo? Wote haki.

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Hivyo flip nyuma mbali.

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tatizo ijayo tuna tatizo namba 33 kwenye faili I / O.

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Kuvuta hii kidogo kidogo.

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Tatizo 33 - Ndiyo?

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>> [Daniel] mimi tu alikuwa swali haraka. Hii nyota, au kinyota,

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ni kuitwa dereferencing wakati matumizi ya kinyota kabla.

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Nini ni kuitwa wakati matumizi ampersand kabla?

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>> Ampersand kabla ni anuani ya operator.

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Basi hebu kitabu nyuma juu.

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Lo. Mimi niko katika mode zoom hivyo siwezi kweli kitabu.

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Kama sisi kuangalia code hii kweli haraka haki hapa,

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tena, kitu kimoja kinachotokea.

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Kama sisi kuangalia code haki hii hapa, juu ya mstari huu ambapo sisi kufanya wito wabadilishane,

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ampersand ni kusema tu "kupata anuani ambayo variable x maisha."

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Wakati compiler yako inaandaa code yako,

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ina kweli kimwili ukaandike mahali katika kumbukumbu kwa wote wa vigezo yako ya kuishi.

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Na hivyo kile compiler unaweza kisha kufanya mara moja ni compiled kila kitu,

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anajua, "Oh, mimi kuweka x katika anuani 10 Mimi kuweka y katika anuani 14.".

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Inaweza kisha jaza maadili haya kwa ajili yenu.

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Hivyo unaweza basi - inaweza kisha kupita katika hii na kupita & y katika vilevile.

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Haya guys kupata anwani, lakini wao pia, wakati wewe kupita yao katika kazi byta,

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habari hii ya aina, hii * int haki hapa, anaiambia compiler,

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"Sawa, tunakwenda kuwa kutafsiri anwani hii kama anuani ya variable integer."

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Kama anwani ya int, ambayo ni tofauti na anwani ya kutofautiana tabia

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kwa sababu int inachukua hadi, kwenye mashine ya 32-bit, inachukua hadi ka 4 wa nafasi,

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ambapo tabia tu inachukua hadi 1 Byte wa nafasi.

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Hivyo ni muhimu kujua pia ni nini - nini anaishi, ni aina gani ya thamani

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anaishi katika anuani kwamba got kupita in

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Au anwani ya kuwa wewe ni kushughulika na.

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Kwa njia hiyo, wengi kujua jinsi bytes wa habari kwa kweli mzigo nje ya RAM yako.

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Na kisha, ndiyo, hii operator dereference, kama wewe walikuwa kuuliza,

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huenda na wanapata habari katika anuani fulani.

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Hivyo anasema, pamoja na hii variable hapa, kutibu yaliyomo kama anuani,

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kwenda kwa anwani hiyo, na kujiondoa, mzigo katika processor mzigo, katika daftari

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maadili halisi au yaliyomo kwamba kuishi katika anuani hiyo.

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Tena maswali? Hizi ni nzuri maswali.

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Ni mengi ya istilahi mpya pia.

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Ni pia aina ya funky, kuona & na * katika maeneo mbalimbali.

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>> Wote haki.

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Hivyo nyuma tatizo 33, faili I / O.

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Hii ilikuwa ni moja ya matatizo hayo ambayo nadhani michache ya mambo yaliyotokea.

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Moja, ni mada uungwana mpya.

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Ni iliwasilishwa pretty hivi karibuni kabla ya chemsha bongo,

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na kisha nadhani ilikuwa aina ya kama moja ya matatizo hayo neno katika math

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ambapo wao kukupa mengi ya habari, lakini wewe kweli si kuishia kuwa na matumizi ya tani ya hiyo.

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sehemu ya kwanza ya tatizo hili ni kuelezea nini faili CSV ni.

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Sasa, faili CSV, kulingana na maelezo, ni koma waliojitenga maadili faili.

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Sababu hizi ni wakati wote kuvutia, na sababu wewe milele matumizi yao,

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ni kwa sababu, jinsi wengi wenu wamewahi kutumia mambo kama Excel?

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Kielelezo zaidi ya wewe, pengine, au kutumia wakati fulani katika maisha yako.

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Utatumia kitu kama Excel.

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Ili kupata data nje ya spreadsheet Excel au kufanya aina yoyote ya usindikaji na hilo,

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kama alitaka kuandika mpango C au Python mpango, Java mpango,

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kukabiliana na data una kuhifadhiwa huko,

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moja ya njia ya kawaida ya kupata nje ni katika faili CSV.

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Na unaweza kufungua Excel na wakati wewe kwenda 'Save As' mazungumzo,

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unaweza kupata nje halisi CSV faili.

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>> Handy kujua jinsi ya kukabiliana na mambo hayo.

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Njia hiyo kazi ni kwamba ni sawa na - I mean, ni kimsingi mimicking spreadsheet,

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ambapo, kama sisi kuona hapa, katika kipande sana kushoto-wengi,

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sisi kuwa na majina yote ya mwisho.

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Hivyo tuna Malan, kisha Hardison, na kisha Bowden, MacWilliam, na kisha Chan.

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Majina yote ya mwisho. Na kisha comma hutenganisha majina ya mwisho kutoka majina kwanza.

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Daudi, Nate, Rob, Tommy, na Zamyla.

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Mimi daima kuchanganya Robby na Tom.

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Na kisha, hatimaye, safu ya tatu ni anwani ya barua pepe.

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Mara baada ya kuelewa kwamba, wengine wa mpango ni haki moja kwa moja kutekeleza.

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Nini tumekuwa kufanyika ili kuiga muundo sawa katika mpango wetu C

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ni tumekuwa kutumika muundo.

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Tutaweza kuanza kucheza na haya zaidi kidogo pia.

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Tuliona yao kwa kidogo kidogo kwanza katika tatizo kuweka 3, tulipokuwa kushughulika na Mkwawa.

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Lakini hii struct wafanyakazi maduka jina la mwisho, jina la kwanza, na barua pepe.

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Tu kama faili wetu CSV alikuwa kuhifadhi.

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Hivyo hii ni haki ya kuwabadili kutoka format moja hadi nyingine.

194
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Tuna kubadili, katika kesi hii, struct wafanyakazi katika mstari,

195
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line comma-waliojitenga, tu kama hiyo.

196
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Je, hiyo mantiki? You guys wote kuchukuliwa quiz,

197
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hivyo mimi kufikiria una angalau alikuwa na muda wa kufikiri juu ya hili.

198
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>> Katika kazi mshahara, tatizo anatuomba kuchukua katika - zoom we'll katika hii kidogo kidogo -

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kuchukua katika muundo wa wafanyakazi, struct wafanyakazi, kwa jina s,

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na append yaliyomo yake na faili wetu staff.csv.

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Ni zinageuka kuwa hii ni haki moja kwa moja kwa kutumia.

202
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Tutaweza aina ya kucheza karibu na kazi hizi kidogo zaidi leo.

203
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Lakini katika kesi hii, kazi fprintf ni kweli muhimu.

204
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Hivyo, pamoja na fprintf, tunaweza magazeti, kama wewe guys wamekuwa wakitumia printf muda huu wote.

205
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Unaweza printf line kwa faili.

206
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Hivyo badala ya maamuzi tu ya kawaida printf wito ambapo wewe kuwapa string format

207
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na kisha wewe kuchukua nafasi ya vigezo vyote kwa hoja zifuatazo,

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na fprintf, hoja yako ya kwanza ni badala faili unataka kuandika.

209
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Kama sisi kuangalia hii katika appliance, kwa mfano, mtu fprintf,

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tunaweza kuona tofauti kati ya printf na fprintf.

211
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Mimi itabidi zoom katika hapa kidogo.

212
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Hivyo, pamoja na printf, sisi kuwapa string format, na kisha hoja ya baadae

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ni vigezo vyote kwa ajili ya uwekaji au badala ndani ya muundo wa kamba yetu.

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Ambapo kwa fprintf, hoja ya kwanza ni kweli hii * faili inayoitwa mkondo.

215
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>> Kusonga nyuma zaidi ya hapa kwa kukodisha yetu,

216
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tumekuwa tayari got faili wetu * mkondo kufunguliwa kwa ajili yetu.

217
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Hiyo ni nini mstari huu kwanza gani; ni kufungua faili staff.csv,

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ni kufungua hiyo katika mode append, na wote wa kushoto kwa sisi kufanya ni

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andika muundo wafanyakazi na faili.

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Na, hebu angalia, kufanya mimi nataka kutumia iPad?

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Mimi itabidi kutumia iPad. Tuna utupu - basi s kuweka hii juu ya meza ili niweze kuandika kidogo bora -

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kuibatilisha kukodisha na inachukua katika hoja moja, muundo wafanyakazi kuitwa s.

223
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Got braces yetu, sisi tumepewa faili wetu * kuitwa faili,

224
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tuna fopen yetu line tuliyopewa

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na mimi itabidi kuandika ni kama dots tangu ni tayari katika pedia.

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Na kisha kwenye line yetu ijayo, sisi ni kwenda kufanya wito kwa fprintf

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na sisi ni kwenda kupita katika faili kwamba tunataka magazeti na,

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na kisha muundo wetu kamba, ambayo -

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Mimi itabidi basi guys kuniambia nini inaonekana kama.

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Vipi kuhusu wewe, Stella? Unajua nini sehemu ya kwanza ya string format inaonekana kama?

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[Stella] mimi nina uhakika. >> Jisikie huru kuuliza Jimmy.

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Unajua, Jimmy?

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[Jimmy] Je, ni tu kuwa mwisho? Mimi sijui. Mimi si uhakika kabisa.

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>> Sawa. Vipi kuhusu, hakuwa mtu yeyote kupata hii sahihi kwenye mtihani?

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No wote wa kulia.

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Ni zinageuka kuwa hapa wote sisi kufanya ni tunataka kila sehemu ya wafanyakazi muundo wetu

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kuchapishwa kwa kama kamba ndani ya faili wetu.

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Sisi tu kutumia badala string tabia ya mara tatu tofauti kwa sababu tuna jina la mwisho

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ikifuatiwa na comma, basi jina la kwanza na kufuatiwa na comma,

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na kisha hatimaye anuani ya barua pepe ambayo ni ikifuatiwa - ambayo si

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kufaa juu ya screen yangu - lakini ni ikifuatiwa na tabia newline.

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Hivyo nina kwenda kuandika tu chini huko.

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Na kisha kufuatia muundo wetu kamba,

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sisi tu substitutions, ambayo sisi kupata kutumia nukuu dot

245
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kuwa tuliona katika tatizo kuweka 3.

246
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Tunaweza kutumia s.last, s.first, na s.email

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mbadala katika maadili hayo matatu katika format string yetu.

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Hivyo ni jinsi gani kwamba kwenda? Mantiki?

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Ndiyo? Hakuna? Inawezekana? Sawa.

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>> Jambo la mwisho kwamba sisi kufanya baada tumekuwa kuchapishwa na baada tumekuwa kufunguliwa faili yetu:

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wakati wowote tumekuwa kufunguliwa faili, sisi daima kuwa kukumbuka kulifunga.

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Kwa sababu vinginevyo sisi kuishia kinachovuja kumbukumbu,

253
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kutumia up descriptors faili.

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Hivyo kuifunga, ambayo kazi gani sisi kutumia? Danieli?

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[Daniel] fclose? >> Fclose, hasa.

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Hivyo sehemu ya mwisho ya tatizo hili lilikuwa vizuri karibu faili, kutumia kazi fclose,

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ambayo tu inaonekana kama kwamba.

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Si pia mambo.

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Cool.

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Basi hiyo ni tatizo 33 juu ya chemsha bongo.

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Tutaweza kuwa dhahiri zaidi faili I / O kuja juu.

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Tutaweza kufanya kidogo zaidi katika hotuba ya leo, au katika sehemu ya leo,

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kwa sababu hiyo ni nini kinaendelea na kuunda wingi wa pset hii ujao.

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Hebu hoja juu ya kutoka Jaribio katika hatua hii. Ndiyo?

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>> [Charlotte]] Mbona fclose (faili) badala ya fclose (staff.csv)?

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>> Ah. Kwa sababu ni zinageuka kuwa - hivyo swali, ambayo ni moja kubwa,

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ni kwa nini, wakati sisi kuandika fclose, ni sisi kuandika fclose (faili) nyota variable

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kinyume na jina la faili, staff.csv? Ni kwamba ni sahihi? Yeah.

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Basi hebu tuangalie. Kama mimi kubadili nyuma kwa mbali yangu,

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na hebu angalia kazi fclose.

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Hivyo kazi fclose kufunga mkondo na inachukua katika pointer mkondo kwamba tunataka kuifunga,

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kinyume na jina halisi faili kwamba tunataka kuifunga.

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Na hii ni kwa sababu ya nyuma ya pazia, wakati kufanya wito kwa fopen,

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unapojitangaza SVG, wewe ni kweli kugawa kumbukumbu kuhifadhi habari kuhusu faili.

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Hivyo una faili pointer kwamba ina taarifa kuhusu faili,

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kama vile ni wazi, ukubwa wake, ambapo sasa uko katika faili,

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hivyo kwamba unaweza kufanya kusoma na kuandika wito kwa mahali fulani ndani ya faili.

278
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Unaishia kufunga pointer badala ya kufunga jina faili.

279
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>> Ndiyo? [Daniel] Hivyo ili kutumia mshahara, ungeweza kusema - jinsi gani kupata pembejeo user?

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Je fprintf kutenda kama GetString kwa maana kwamba itabidi kusubiri kwa ajili ya pembejeo user

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na kuuliza wewe andika haya - au kusubiri kwa wewe andika mambo haya matatu katika?

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Au wewe haja ya kutumia kitu kutekeleza kukodisha?

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>> Yeah. Hivyo sisi siyo - Swali, ni jinsi gani sisi kupata pembejeo user

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ili kutekeleza kukodisha? Na nini sisi hapa ni mpigaji wa kukodisha,

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kupita katika hii struct wafanyakazi na yote ya data kuhifadhiwa katika struct tayari.

286
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Hivyo fprintf ni uwezo wa kuandika tu kwamba data moja kwa moja na faili.

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Hakuna kusubiri kwa ajili ya pembejeo mtumiaji.

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user Tayari aliyopewa pembejeo na vizuri kuweka katika struct hii wafanyakazi.

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Na mambo, bila shaka, inaweza kuvunja kama yoyote ya kuyatumia wale walikuwa null,

290
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hivyo sisi kitabu nyuma hadi hapa na sisi kuangalia struct yetu.

291
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Tuna string mwisho, kamba ya kwanza, kamba ya barua pepe.

292
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Sasa tunajua kwamba wale wote kweli, chini ya Hood, ni Char * vigezo.

293
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Kwamba wanaweza au kuwa akizungumzia null.

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Wanaweza kuwa akizungumzia kumbukumbu juu ya chungu,

295
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labda kumbukumbu juu ya stack.

296
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Sisi kwa kweli sijui, lakini ikiwa yoyote ya kuyatumia haya ni null, au batili,

297
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kwamba utakuwa dhahiri ajali mshahara wetu kazi.

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Hiyo ilikuwa kitu ambacho ilikuwa ni aina ya zaidi ya upeo wa mtihani.

299
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Sisi siyo wasiwasi juu ya hilo.

300
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Mkuu. Sawa. Hivyo kuhama kutoka chemsha bongo.

301
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>> Hebu kuifunga guy, na sisi ni kwenda kuangalia pset 4.

302
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Hivyo kama wewe guys kuangalia spec pset, mara moja unaweza kupata hiyo, cs50.net/quizzes,

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sisi ni kwenda kupitia wachache wa matatizo leo sehemu.

304
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Mimi nina scrolling chini - sehemu ya maswali huanza kwenye ukurasa wa tatu wa spec pset.

305
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Na sehemu ya kwanza anauliza wewe kwenda na kuangalia mfupi juu ya imetuma na mabomba.

306
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Ambayo ilikuwa aina ya short baridi, inaonyesha baadhi ya mwezi, baridi tricks mstari amri kwamba unaweza kutumia.

307
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Na kisha sisi tumepewa maswali kadhaa kwa ajili yenu pia.

308
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Hii swali la kwanza kuhusu mito, ambayo printf anaandika by default,

309
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sisi aina ya kuguswa juu kidogo kidogo tu wakati iliyopita.

310
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Hii fprintf kwamba tulikuwa tu kujadili inachukua katika mkondo faili * kama hoja yake.

311
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fclose inachukua katika mkondo * faili kama vile,

312
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na thamani ya kurudi kwa fopen inakupa * faili mkondo pia.

313
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sababu hatujaona walio kabla wakati tumekuwa kushughulikiwa na printf

314
00:26:36,060 --> 00:26:39,450
ni kwa sababu ana printf mkondo default.

315
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Na mkondo default ambayo anaandika

316
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utagundua kuhusu katika muda mfupi.

317
00:26:45,190 --> 00:26:50,080
Hivyo dhahiri kuangalia ni.

318
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>> Katika sehemu ya leo, sisi ni kwenda kuzungumza kidogo kuhusu GDB,

319
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tangu zaidi ya ukoo wewe ni pamoja na hayo, mazoezi zaidi kupata pamoja na hayo,

320
00:26:57,720 --> 00:27:01,390
bora na uwezo utakuwa kwa kweli kuwasaka mende katika code yako mwenyewe.

321
00:27:01,390 --> 00:27:05,540
Hii kasi ya mchakato wa debugging juu mno.

322
00:27:05,540 --> 00:27:09,230
Hivyo kwa kutumia printf, kila wakati kufanya kwamba una recompile code yako,

323
00:27:09,230 --> 00:27:13,000
una kuendesha tena, wakati mwingine una hoja wito printf kote,

324
00:27:13,000 --> 00:27:17,100
maoni nje code, ni tu inachukua muda.

325
00:27:17,100 --> 00:27:20,850
Lengo letu ni kujaribu na kuwashawishi kwamba kwa GDB, unaweza kimsingi

326
00:27:20,850 --> 00:27:26,810
printf chochote katika hatua yoyote katika code yako na wewe kamwe kuwa na recompile yake.

327
00:27:26,810 --> 00:27:35,120
Huwezi kuwa na kuanza na kuendelea guessing ambapo kwa printf ijayo.

328
00:27:35,120 --> 00:27:40,910
Kitu cha kwanza kufanya ni nakala line hii na kupata kanuni ya sehemu ya mbali ya mtandao.

329
00:27:40,910 --> 00:27:47,530
Mimi nina kuiga line hii ya kificho kwamba anasema, "wget ​​http://cdn.cs50.net".

330
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Mimi naenda nakala yake.

331
00:27:49,510 --> 00:27:55,950
Mimi nina kwenda juu kwa appliance wangu, zoom nje hivyo unaweza kuona nini mimi kufanya,

332
00:27:55,950 --> 00:28:01,890
pasting ni huko, na wakati mimi hit Enter, amri hii wget literally ni mtandao kupata.

333
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Ni kwenda kubomoa faili hii mbali ya mtandao,

334
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na ni kwenda kuokoa ni saraka ya sasa.

335
00:28:11,790 --> 00:28:21,630
Sasa kama mimi kuorodhesha saraka yangu sasa unaweza kuona kwamba mimi nimepata faili hii section5.zip haki huko.

336
00:28:21,630 --> 00:28:25,260
njia ya kukabiliana na kwamba guy ni unzip yake,

337
00:28:25,260 --> 00:28:27,650
ambayo unaweza kufanya katika mstari amri, kama hii.

338
00:28:27,650 --> 00:28:31,880
Section5.zip.

339
00:28:31,880 --> 00:28:36,980
Kwamba kutakuwa na unzip yake, kutengeneza folda kwa ajili yangu,

340
00:28:36,980 --> 00:28:40,410
inflate yote yaliyomo, kuziweka katika huko.

341
00:28:40,410 --> 00:28:47,410
Hivyo sasa naweza kwenda katika sehemu ya saraka yangu 5 kutumia amri cd.

342
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Wazi screen kutumia wazi. Hivyo wazi screen.

343
00:28:58,310 --> 00:29:02,280
Sasa mimi nimepata nzuri safi terminal kushughulikia.

344
00:29:02,280 --> 00:29:06,200
>> Sasa kama mimi orodha files wote kwamba mimi kuona katika saraka hii,

345
00:29:06,200 --> 00:29:12,270
unaweza kuona kwamba mimi nimepata files nne: buggy1, buggy2, buggy3, na buggy4.

346
00:29:12,270 --> 00:29:16,180
Nimekuwa pia got files yao sambamba. C.

347
00:29:16,180 --> 00:29:20,400
Sisi siyo kwenda kuangalia files. C kwa sasa.

348
00:29:20,400 --> 00:29:24,140
Badala yake, tunakwenda kuzitumia wakati sisi kufungua GDB.

349
00:29:24,140 --> 00:29:28,220
Tumekuwa naendelea yao karibu ili tuweze kupata code halisi chanzo wakati sisi ni kutumia GDB,

350
00:29:28,220 --> 00:29:32,740
lakini lengo la sehemu hii ya sehemu ni kwa tinker karibu na GDB

351
00:29:32,740 --> 00:29:40,370
na kuona ni jinsi gani tunaweza kuitumia kufikiri nini kinaendelea kibaya na kila moja ya hizi programu Buggy nne.

352
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Hivyo sisi ni kwenda tu kuzunguka chumba kweli haraka,

353
00:29:43,380 --> 00:29:47,000
na mimi naenda kuuliza mtu kukimbia moja ya mipango Buggy,

354
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na kisha tutaweza kwenda kama kikundi kupitia GDB, na tutaweza kuona nini tunaweza kufanya kwa kurekebisha programu hizi,

355
00:29:54,730 --> 00:29:58,460
au kwa angalau kutambua nini kinaendelea katika makosa ya kila mmoja wao.

356
00:29:58,460 --> 00:30:04,760
Hebu kuanza hapa kwa Danieli. Je kukimbia buggy1? Hebu kuona nini kinatokea.

357
00:30:04,760 --> 00:30:09,470
[Daniel] Ni anasema kuna kosa maombi. >> Yeah. Hasa.

358
00:30:09,470 --> 00:30:12,460
Hivyo kama mimi kukimbia buggy1, mimi kupata kosa seg.

359
00:30:12,460 --> 00:30:16,210
Katika hatua hii, mimi naweza kwenda na kufungua buggy1.c,

360
00:30:16,210 --> 00:30:19,450
kujaribu na kufikiri nini kinaendelea vibaya,

361
00:30:19,450 --> 00:30:22,000
lakini moja ya mambo ya obnoxious kuhusu kosa hili seg kosa

362
00:30:22,000 --> 00:30:27,610
ni kwamba haina kukuambia juu ya nini mstari wa mambo mpango kweli potoka na kukatika.

363
00:30:27,610 --> 00:30:29,880
Wewe aina ya kuwa na kuangalia code

364
00:30:29,880 --> 00:30:33,990
na takwimu nje kwa kutumia dhana na kuangalia au printf kwa kuona nini kinaendelea vibaya.

365
00:30:33,990 --> 00:30:37,840
Moja ya mambo ya coolest kuhusu GDB ni kwamba ni kweli, kweli rahisi

366
00:30:37,840 --> 00:30:42,170
kufikiri mstari wa saa ambayo programu yako shambulio.

367
00:30:42,170 --> 00:30:46,160
Ni kabisa na thamani yake na kuitumia, hata kama tu kwa ajili hiyo.

368
00:30:46,160 --> 00:30:56,190
Hivyo kwa Boot juu GDB, ninapoandika GDB, na kisha mimi kuwapa njia ya executable kwamba nataka kukimbia.

369
00:30:56,190 --> 00:31:01,960
Hapa mimi nina kuandika gdb ./buggy1.

370
00:31:01,960 --> 00:31:06,600
Hit Ingiza. Anitiaye habari hii yote hakimiliki,

371
00:31:06,600 --> 00:31:13,000
na chini hapa utaona mstari huu kwamba anasema, "ishara Akisoma / nyumbani /

372
00:31:13,000 --> 00:31:17,680
jharvard/section5/buggy1. "

373
00:31:17,680 --> 00:31:22,060
Na kama yote inakwenda vizuri, utaona ni magazeti ujumbe kwamba inaonekana kama hii.

374
00:31:22,060 --> 00:31:25,500
Ni itabidi kusoma alama, hivyo itabidi kusema "mimi nina kusoma alama kutoka executable faili yako,"

375
00:31:25,500 --> 00:31:29,900
na kisha itakuwa na hii "kufanyika" ujumbe zaidi ya hapa.

376
00:31:29,900 --> 00:31:35,410
Kama unaweza kuona baadhi ya tofauti nyingine ya hii, au unaweza kuona ni hakuweza kupata alama

377
00:31:35,410 --> 00:31:41,460
au kitu kama hicho, nini maana ya ni kwamba wewe tu si compiled executable yako vizuri.

378
00:31:41,460 --> 00:31:49,980
Wakati sisi kukusanya mipango kwa ajili ya matumizi na GDB, inabidi kutumia bendera maalum-g,

379
00:31:49,980 --> 00:31:54,540
na kwamba ni kosa kwa default kama wewe kukusanya mipango yako, tu na kuandika kufanya

380
00:31:54,540 --> 00:31:59,320
au kufanya Buggy au kufanya kuokoa, yoyote ya wale.

381
00:31:59,320 --> 00:32:07,800
Lakini kama wewe ni kuandaa manually na Clang, basi itabidi kwenda katika na ni pamoja na kwamba-g bendera.

382
00:32:07,800 --> 00:32:10,310
>> Katika hatua hii, sasa kwamba tuna GDB wetu haraka,

383
00:32:10,310 --> 00:32:12,310
ni pretty rahisi kuendesha programu.

384
00:32:12,310 --> 00:32:19,740
Tunaweza aidha aina ya kukimbia, au tunaweza aina tu r.

385
00:32:19,740 --> 00:32:22,820
Wengi GDB amri inaweza kuwa abbreviated.

386
00:32:22,820 --> 00:32:25,940
Kawaida kwa moja tu au barua wanandoa, ambayo ni pretty nice.

387
00:32:25,940 --> 00:32:30,980
Hivyo Saad, kama aina r na hit Enter, nini kitatokea?

388
00:32:30,980 --> 00:32:39,390
[Saad] I got SIGSEGV, kosa segmentation, na kisha gobbledygook hii yote.

389
00:32:39,390 --> 00:32:43,650
>> Yeah.

390
00:32:43,650 --> 00:32:47,990
Kama sisi ni kuona kwenye screen hivi sasa, na kama Saad alisema,

391
00:32:47,990 --> 00:32:53,430
wakati sisi aina kukimbia au r na hit Enter, sisi bado kupata huo seg kosa.

392
00:32:53,430 --> 00:32:55,830
Hivyo kutumia GDB haina kutatua tatizo letu.

393
00:32:55,830 --> 00:32:59,120
Lakini inatupa baadhi gobbledygook, na zinageuka kuwa hii gobbledygook

394
00:32:59,120 --> 00:33:03,080
kweli inatuambia ambapo ni kinachotokea.

395
00:33:03,080 --> 00:33:10,680
Kuchanganua hii kidogo kidogo, hii kidogo kwanza ni kazi ambayo kila kitu kinaendelea vibaya.

396
00:33:10,680 --> 00:33:20,270
Kuna hii __ strcmp_sse4_2, na inatuambia kwamba kinachotokea katika faili hii

397
00:33:20,270 --> 00:33:29,450
kuitwa sysdeps/i386, yote hii, tena, aina ya fujo - lakini line 254.

398
00:33:29,450 --> 00:33:31,670
Hiyo ni aina ya vigumu kuchanganua. Kawaida wakati unaweza kuona mambo kama haya,

399
00:33:31,670 --> 00:33:38,770
hiyo ina maana kwamba ni seg faulting katika moja ya maktaba mfumo.

400
00:33:38,770 --> 00:33:43,220
Hivyo kitu cha kufanya na strcmp. You guys tumeona strcmp kabla.

401
00:33:43,220 --> 00:33:52,730
Si pia mambo, lakini anafanya hii ina maana kwamba strcmp ni kuvunjwa au kwamba kuna tatizo na strcmp?

402
00:33:52,730 --> 00:33:57,110
Unafikiri, Alexander?

403
00:33:57,110 --> 00:34:04,890
[Alexander] Je kwamba - ni 254 mstari? Na - sio binary, lakini siyo taken zao,

404
00:34:04,890 --> 00:34:10,590
na kisha kuna lugha nyingine kwa ajili ya kazi ya kila. Ni kwamba 254 katika kazi hiyo, au -?

405
00:34:10,590 --> 00:34:21,460
>> Ni line 254. Inaonekana kama katika faili hii. Hii, hivyo ni mkutano code pengine.

406
00:34:21,460 --> 00:34:25,949
>> Lakini, mimi nadhani jambo kubwa zaidi ni, kwa sababu tumekuwa Gotten kosa seg,

407
00:34:25,949 --> 00:34:29,960
na inaonekana kama ni kuja kutoka kazi strcmp,

408
00:34:29,960 --> 00:34:38,030
nini hii inadokeza, basi, strcmp kwamba ni kuvunjwa?

409
00:34:38,030 --> 00:34:42,290
Ni lazima si, hopefully. Hivyo tu kwa sababu una kosa segmentation

410
00:34:42,290 --> 00:34:49,480
katika moja ya kazi za mfumo, kawaida hiyo ina maana kwamba wewe tu si iitwayo kwa usahihi.

411
00:34:49,480 --> 00:34:52,440
kitu ya haraka ya kufanya kufikiri nini ni kweli kinachoendelea

412
00:34:52,440 --> 00:34:55,500
wakati unaweza kuona kitu kama mambo haya, wakati wowote unaweza kuona kosa seg,

413
00:34:55,500 --> 00:34:59,800
hasa kama una mpango wa hiyo kutumia zaidi kuliko tu kuu,

414
00:34:59,800 --> 00:35:03,570
ni kutumia backtrace.

415
00:35:03,570 --> 00:35:13,080
Mimi abbreviate backtrace kwa kuandika bt, kinyume na neno kamili backtrace.

416
00:35:13,080 --> 00:35:16,510
Lakini Charlotte, nini kinatokea pale unapoandika bt na hit Enter?

417
00:35:16,510 --> 00:35:23,200
[Charlotte] Inaonyesha yangu mistari mbili, line 0 na mstari 1.

418
00:35:23,200 --> 00:35:26,150
>> Yeah. Hivyo mstari na mstari 0 1.

419
00:35:26,150 --> 00:35:34,560
Hizi ni halisi stack muafaka kuwa walikuwa sasa katika kucheza wakati mpango wako kugonga.

420
00:35:34,560 --> 00:35:42,230
Kuanzia sura topmost, sura 0, na kwenda chini-wengi, ambayo ni sura ya 1.

421
00:35:42,230 --> 00:35:45,140
Frame yetu topmost ni sura strcmp.

422
00:35:45,140 --> 00:35:50,080
Unaweza kufikiri ya hii kama sawa na kwamba tatizo tulikuwa tu kufanya juu ya chemsha bongo kwa kuyatumia,

423
00:35:50,080 --> 00:35:54,890
ambapo tulikuwa wabadilishane stack frame juu ya sura kuu stack,

424
00:35:54,890 --> 00:35:59,700
na tulikuwa na vigezo kwamba byta alikuwa kutumia juu ya vigezo kwamba alikuwa kutumia kuu.

425
00:35:59,700 --> 00:36:08,440
Hapa ajali wetu kilichotokea katika kazi yetu strcmp, ambayo aliitwa na kazi yetu kuu,

426
00:36:08,440 --> 00:36:14,370
na backtrace anatupa si tu kazi katika mambo ambayo alishindwa,

427
00:36:14,370 --> 00:36:16,440
lakini ni pia anatuambia ambapo kila kitu aliitwa kutoka.

428
00:36:16,440 --> 00:36:18,830
Hivyo kama mimi kitabu juu zaidi kidogo kwa haki,

429
00:36:18,830 --> 00:36:26,110
tunaweza kuona kwamba yeah, tulipokuwa kwenye mstari 254 ya faili hii strcmp-sse4.s.

430
00:36:26,110 --> 00:36:32,540
Lakini wito huo ulitolewa katika buggy1.c, mstari 6.

431
00:36:32,540 --> 00:36:35,960
Hivyo kwamba maana tunaweza kufanya - ni sisi unaweza tu kwenda kuangalia nje na kuona nini kinachoendelea

432
00:36:35,960 --> 00:36:39,930
katika buggy1.c, mstari 6.

433
00:36:39,930 --> 00:36:43,780
Tena, kuna njia kadhaa za kufanya hivyo. Moja ni exit nje ya GDB

434
00:36:43,780 --> 00:36:49,460
au kuwa na code yako wazi katika dirisha lingine na rejea msalaba.

435
00:36:49,460 --> 00:36:54,740
Kwamba, katika yenyewe, ni pretty Handy kwa sababu sasa kama wewe ni katika masaa ya ofisi

436
00:36:54,740 --> 00:36:57,220
na nimepata kosa seg na TF yako s wanashangaa ambapo kila kitu kilikuwa kuvunja,

437
00:36:57,220 --> 00:36:59,710
unaweza tu kusema, "Oh, mstari 6 sijui nini kinaendelea.,

438
00:36:59,710 --> 00:37:03,670
lakini kitu kuhusu mstari 6 ni kusababisha mpango wangu kuvunja. "

439
00:37:03,670 --> 00:37:10,430
njia nyingine ya kufanya hivyo ni unaweza kutumia amri hii inaitwa orodha katika GDB.

440
00:37:10,430 --> 00:37:13,650
Unaweza pia abbreviate kwa l.

441
00:37:13,650 --> 00:37:18,910
Hivyo kama sisi hit l, je, sisi hapa?

442
00:37:18,910 --> 00:37:21,160
Sisi kupata rundo zima ya mambo weird.

443
00:37:21,160 --> 00:37:26,030
Hii ni halisi mkutano code

444
00:37:26,030 --> 00:37:29,860
kwamba ni katika strcmp_sse4_2.

445
00:37:29,860 --> 00:37:32,440
Hii inaonekana aina ya funky,

446
00:37:32,440 --> 00:37:36,520
na sababu sisi ni kupata hii ni kwa sababu sasa hivi,

447
00:37:36,520 --> 00:37:40,160
GDB ana yetu katika sura 0.

448
00:37:40,160 --> 00:37:43,070
>> Hivyo wakati wowote sisi kuangalia vigezo, wakati wowote sisi kuangalia chanzo code,

449
00:37:43,070 --> 00:37:50,530
sisi ni kuangalia chanzo code linafanywa na sura stack tuko sasa in

450
00:37:50,530 --> 00:37:53,200
Hivyo ili kupata kitu chochote maana, tuna

451
00:37:53,200 --> 00:37:57,070
hoja kwa frame stack kwamba mantiki zaidi.

452
00:37:57,070 --> 00:38:00,180
Katika kesi hiyo, kuu stack frame zingeweza kidogo maana zaidi,

453
00:38:00,180 --> 00:38:02,680
kwa sababu kwamba alikuwa kweli kificho kwamba sisi aliandika.

454
00:38:02,680 --> 00:38:05,330
Si code strcmp.

455
00:38:05,330 --> 00:38:08,650
njia unaweza hoja kati ya muafaka, katika kesi hii, kwa sababu tuna mbili,

456
00:38:08,650 --> 00:38:10,430
tuna 0 na 1,

457
00:38:10,430 --> 00:38:13,650
unaweza kufanya hivyo kwa juu na amri chini.

458
00:38:13,650 --> 00:38:18,480
Kama mimi hoja juu frame moja,

459
00:38:18,480 --> 00:38:21,770
sasa mimi nina katika sura kuu stack.

460
00:38:21,770 --> 00:38:24,330
Mimi unaweza hoja chini kwenda nyuma ambapo mimi nilikuwa,

461
00:38:24,330 --> 00:38:32,830
kwenda juu tena, kwenda chini tena, na kwenda juu tena.

462
00:38:32,830 --> 00:38:39,750
Kama umewahi kufanya mpango wako katika GDB, kupata ajali, unaweza kupata backtrace,

463
00:38:39,750 --> 00:38:42,380
na unaweza kuona kwamba ni katika baadhi faili kwamba huwezi kujua nini kinaendelea.

464
00:38:42,380 --> 00:38:45,460
Unaweza kujaribu orodha, code haangalii familiar na wewe,

465
00:38:45,460 --> 00:38:48,150
kuangalia muafaka yako na takwimu kutoka wapi.

466
00:38:48,150 --> 00:38:51,010
Wewe pengine katika sura makosa stack.

467
00:38:51,010 --> 00:38:58,760
Au angalau wewe ni katika sura ya stack ambayo si moja kuwa unaweza kweli Debug.

468
00:38:58,760 --> 00:39:03,110
Sasa kwa kuwa tuko katika sura sahihi stack, tuko katika kuu,

469
00:39:03,110 --> 00:39:08,100
sasa tunaweza kutumia amri orodha kufikiri nini line ilikuwa.

470
00:39:08,100 --> 00:39:13,590
Na unaweza kuona, ni printed hivyo kwa ajili yetu hapa hapa.

471
00:39:13,590 --> 00:39:19,470
Lakini tunaweza hit kuorodhesha wote ni sawa, na orodha hii inatupa printout nzuri

472
00:39:19,470 --> 00:39:23,920
wa chanzo halisi kificho kwamba kinaendelea katika hapa.

473
00:39:23,920 --> 00:39:26,420
>> Hasa, tunaweza kuangalia mstari 6.

474
00:39:26,420 --> 00:39:29,330
Tunaweza kuona nini kinaendelea hapa.

475
00:39:29,330 --> 00:39:31,250
Na inaonekana kama sisi ni kufanya kulinganisha string

476
00:39:31,250 --> 00:39:41,050
kati ya string "CS50 miamba" na argv [1].

477
00:39:41,050 --> 00:39:45,700
Kitu kuhusu hili crashing.

478
00:39:45,700 --> 00:39:54,120
Hivyo Missy, je, una mawazo yoyote juu ya nini kinaweza kuwa kinachoendelea hapa?

479
00:39:54,120 --> 00:39:59,400
[Missy] Mimi sijui ni kwa nini ni crashing. >> Wewe sijui nini ni crashing?

480
00:39:59,400 --> 00:40:02,700
Jimmy, mawazo yoyote?

481
00:40:02,700 --> 00:40:06,240
[Jimmy] Mimi si uhakika kabisa, lakini mara ya mwisho sisi kutumika string kulinganisha,

482
00:40:06,240 --> 00:40:10,260
au strcmp, tulikuwa kama kesi tatu tofauti chini yake.

483
00:40:10,260 --> 00:40:12,800
Hatukuwa na ==, sidhani, haki katika mstari ule wa kwanza.

484
00:40:12,800 --> 00:40:16,700
Badala yake ilikuwa waliojitenga katika tatu, na moja ilikuwa == 0,

485
00:40:16,700 --> 00:40:19,910
moja alikuwa <0, nadhani, na moja ilikuwa> 0.

486
00:40:19,910 --> 00:40:22,590
Hivyo labda kitu kama hicho? >> Yeah. Hivyo kuna suala hili

487
00:40:22,590 --> 00:40:27,200
wa tunafanya kulinganisha kwa usahihi?

488
00:40:27,200 --> 00:40:31,660
Stella? Mawazo yoyote?

489
00:40:31,660 --> 00:40:38,110
[Stella] mimi nina uhakika. >> Si uhakika. Danieli? Mawazo? Sawa.

490
00:40:38,110 --> 00:40:44,770
Ni zinageuka nini kinatokea hapa hapa ni wakati sisi mbio mpango

491
00:40:44,770 --> 00:40:48,370
na sisi got kosa seg, wakati wewe mbio mpango kwa mara ya kwanza, Danieli,

492
00:40:48,370 --> 00:40:50,800
gani kuwapa yoyote hoja mstari amri?

493
00:40:50,800 --> 00:40:58,420
[Daniel] No No >> Katika kesi hiyo, ni nini thamani ya argv [1]?

494
00:40:58,420 --> 00:41:00,920
>> Kuna faida yeyote. >> Haki.

495
00:41:00,920 --> 00:41:06,120
Naam, hakuna mwafaka string thamani.

496
00:41:06,120 --> 00:41:10,780
Lakini kuna baadhi ya thamani. Nini thamani ya kwamba anapata kuhifadhiwa katika huko?

497
00:41:10,780 --> 00:41:15,130
>> Thamani takataka? >> Ni ama thamani ya takataka au, katika kesi hii,

498
00:41:15,130 --> 00:41:19,930
mwisho wa safu argv daima ni terminated na null.

499
00:41:19,930 --> 00:41:26,050
Basi nini kweli got kuhifadhiwa katika kuna null.

500
00:41:26,050 --> 00:41:30,810
njia nyingine ya kutatua hili, badala ya kufikiria njia,

501
00:41:30,810 --> 00:41:33,420
ni kujaribu kuchapa nje.

502
00:41:33,420 --> 00:41:35,880
Hii ni pale ambapo mimi alikuwa akisema kwamba kwa kutumia GDB ni kubwa,

503
00:41:35,880 --> 00:41:40,640
kwa sababu unaweza magazeti nje vigezo vyote, maadili yote ya kwamba unataka

504
00:41:40,640 --> 00:41:43,230
kutumia hii Handy-dandy p amri.

505
00:41:43,230 --> 00:41:48,520
Hivyo kama ninapoandika p na kisha ninapoandika thamani ya variable au jina la kutofautiana,

506
00:41:48,520 --> 00:41:55,320
kusema, argc, naona ya kuwa argc ni 1.

507
00:41:55,320 --> 00:42:01,830
Kama mimi nataka magazeti nje argv [0], siwezi kufanya hivyo tu kama hiyo.

508
00:42:01,830 --> 00:42:04,840
Na kama tuliona, argv [0] daima ni jina la mpango wako,

509
00:42:04,840 --> 00:42:06,910
daima jina la kutekelezwa.

510
00:42:06,910 --> 00:42:09,740
Hapa unaweza kuona ni got kamili njia jina.

511
00:42:09,740 --> 00:42:15,920
Mimi pia magazeti nje argv [1] na kuona nini kinatokea.

512
00:42:15,920 --> 00:42:20,890
>> Hapa sisi got aina hii ya thamani ya fumbo.

513
00:42:20,890 --> 00:42:23,890
Sisi got hii 0x0.

514
00:42:23,890 --> 00:42:27,850
Kumbuka mwanzoni mwa muhula wakati sisi aliyesema kuhusu idadi hexadesimoli?

515
00:42:27,850 --> 00:42:34,680
Au swali kidogo mwisho wa pset 0 kuhusu jinsi ya kuwakilisha 50 katika hex?

516
00:42:34,680 --> 00:42:39,410
njia ya sisi kuandika hex idadi katika CS, tu si kuwavurugia wenyewe

517
00:42:39,410 --> 00:42:46,080
pamoja na idadi decimal, ni sisi daima kiambishi yao na 0x.

518
00:42:46,080 --> 00:42:51,420
Hivyo hii kiambishi awali 0x daima tu ina maana kutafsiri idadi zifuatazo kama idadi hexadesimoli,

519
00:42:51,420 --> 00:42:57,400
si kama kamba, si kama idadi decimal, si kama idadi binary.

520
00:42:57,400 --> 00:43:02,820
Tangu idadi 5-0 ni idadi halali katika hexadesimoli.

521
00:43:02,820 --> 00:43:06,240
Na ni idadi katika decimal, 50.

522
00:43:06,240 --> 00:43:10,050
Hivyo hii ni jinsi tu sisi disambiguate.

523
00:43:10,050 --> 00:43:14,860
Hivyo 0x0 njia hexadesimoli 0, ambayo pia ni decimal 0, binary 0.

524
00:43:14,860 --> 00:43:17,030
Ni tu 0 thamani.

525
00:43:17,030 --> 00:43:22,630
Ni zinageuka kuwa hii ni nini null ni, kwa kweli, katika kumbukumbu.

526
00:43:22,630 --> 00:43:25,940
Null ni 0.

527
00:43:25,940 --> 00:43:37,010
Hapa, kipengele kuhifadhiwa katika argv [1] ni null.

528
00:43:37,010 --> 00:43:45,220
Hivyo sisi ni kujaribu kulinganisha yetu "miamba CS50" kamba kamba null.

529
00:43:45,220 --> 00:43:48,130
Hivyo dereferencing null, kujaribu kupata mambo katika null,

530
00:43:48,130 --> 00:43:55,050
wale ni kawaida ya kwenda kusababisha baadhi ya aina ya segmentation kosa au nyingine mambo mabaya kutokea.

531
00:43:55,050 --> 00:43:59,350
Na zinageuka kuwa strcmp haina kuangalia kuona

532
00:43:59,350 --> 00:44:04,340
kama au wewe ve kupita katika thamani hiyo null.

533
00:44:04,340 --> 00:44:06,370
Badala yake, ni tu inakwenda mbele, anajaribu kufanya jambo yake,

534
00:44:06,370 --> 00:44:14,640
na kama ni seg makosa, ni seg makosa, na ni tatizo lako. Una kwenda kurekebisha.

535
00:44:14,640 --> 00:44:19,730
Kweli haraka, jinsi tunavyoweza kurekebisha tatizo hili? Charlotte?

536
00:44:19,730 --> 00:44:23,540
[Charlotte] Unaweza kuangalia kama kutumia.

537
00:44:23,540 --> 00:44:32,240
Hivyo kama argv [1] ni null, == 0, kisha kurudi 1, au kitu [unintelligible].

538
00:44:32,240 --> 00:44:34,590
>> Yeah. Basi hiyo ni moja kubwa njia ya kufanya hivyo, kama tunaweza kuangalia kuona,

539
00:44:34,590 --> 00:44:39,230
thamani sisi ni juu ya kupita katika strcmp, argv [1] Je, ni null?

540
00:44:39,230 --> 00:44:45,830
Kama ni null, basi tunaweza kusema sawa, abort.

541
00:44:45,830 --> 00:44:49,450
>> njia zaidi ya kawaida ya kufanya hivyo ni kutumia thamani argc.

542
00:44:49,450 --> 00:44:52,040
Unaweza kuona haki hapa katika mwanzo wa kuu,

543
00:44:52,040 --> 00:44:58,040
sisi omitted kwamba mtihani wa kwanza kwamba sisi kawaida kufanya wakati sisi kutumia hoja mstari amri,

544
00:44:58,040 --> 00:45:05,240
ambayo ni mtihani kama au thamani yetu argc ni nini sisi kutarajia.

545
00:45:05,240 --> 00:45:10,290
Katika kesi hii, sisi ni kutarajia hoja angalau mbili,

546
00:45:10,290 --> 00:45:13,660
jina la mpango plus moja nyingine.

547
00:45:13,660 --> 00:45:17,140
Kwa sababu sisi ni juu ya kutumia hoja pili kulia hapa.

548
00:45:17,140 --> 00:45:21,350
Hivyo kuwa na baadhi ya aina ya mtihani kabla, kabla ya wito wetu strcmp

549
00:45:21,350 --> 00:45:37,390
kwamba vipimo kama au argv ni angalau 2, ingekuwa pia kufanya aina moja ya kitu.

550
00:45:37,390 --> 00:45:40,620
Tunaweza kuona kama kwamba kazi kwa kuendesha mpango tena.

551
00:45:40,620 --> 00:45:45,610
Daima unaweza kuanzisha upya mpango wako ndani ya GDB, ambayo ni nzuri kwa kweli.

552
00:45:45,610 --> 00:45:49,310
Unaweza kukimbia, na wakati kupita katika hoja kwa mpango wako,

553
00:45:49,310 --> 00:45:53,060
wewe kupita yao katika wakati wito kukimbia, si wakati Boot juu GDB.

554
00:45:53,060 --> 00:45:57,120
Kwa njia hiyo unaweza kushika kuliungama mpango wako kwa hoja tofauti kila wakati.

555
00:45:57,120 --> 00:46:08,080
Hivyo kukimbia, au tena, mimi unaweza aina r, na hebu angalia nini kinatokea kama sisi aina "hello".

556
00:46:08,080 --> 00:46:11,140
Ni daima kuuliza wewe kama unataka kuanza yake tangu mwanzo tena.

557
00:46:11,140 --> 00:46:17,490
Kawaida, wewe unataka kuanza yake tangu mwanzo tena.

558
00:46:17,490 --> 00:46:25,010
Na katika hatua hii, ni restarts tena, ni Prints nje

559
00:46:25,010 --> 00:46:28,920
mpango kwamba sisi ni mbio, buggy1, na hoja hello,

560
00:46:28,920 --> 00:46:32,720
na Prints hii nje ya kiwango; inasema, "Unaweza kupata D," sura ya huzuni.

561
00:46:32,720 --> 00:46:37,610
Lakini hatukuwa seg kosa. Ni alisema mchakato kwamba exited kawaida.

562
00:46:37,610 --> 00:46:39,900
Hivyo kwamba inaonekana pretty nzuri.

563
00:46:39,900 --> 00:46:43,050
Hakuna kosa zaidi seg, sisi kuifanya nyuma,

564
00:46:43,050 --> 00:46:48,190
hivyo inaonekana kama kwamba ilikuwa kweli seg kosa bug kwamba sisi kupata.

565
00:46:48,190 --> 00:46:51,540
Bahati mbaya, ni inatuambia kwamba sisi ni kupata D.

566
00:46:51,540 --> 00:46:54,090
>> Tunaweza kwenda nyuma na kuangalia code na kuona nini kinaendelea huko

567
00:46:54,090 --> 00:46:57,980
kufikiri nini ilikuwa - ni kwa nini alikuwa akitwambia kwamba tulipata D.

568
00:46:57,980 --> 00:47:03,690
Hebu angalia, hapa ilikuwa hii printf akisema kwamba got D.

569
00:47:03,690 --> 00:47:08,540
Kama sisi aina orodha, kama wewe kushika kuandika orodha, ni kuvaa iterating chini kupitia mpango wako,

570
00:47:08,540 --> 00:47:10,940
hivyo nitawaonyesheani kwanza mistari michache ya programu yako.

571
00:47:10,940 --> 00:47:15,450
Kisha nitawaonyesheani ijayo mistari michache, na chunk ijayo na chunk ijayo.

572
00:47:15,450 --> 00:47:18,240
Na nitaendelea kujaribu kwenda chini.

573
00:47:18,240 --> 00:47:21,180
Na sasa tutaweza kupata na "kujipanga idadi 16 ni nje ya mbalimbali."

574
00:47:21,180 --> 00:47:23,940
Kwa sababu tu ina mistari 15.

575
00:47:23,940 --> 00:47:30,310
Kama wewe kupata hatua hii na wako anashangaa, "Nitafanya nini?" unaweza kutumia amri msaada.

576
00:47:30,310 --> 00:47:34,340
Matumizi ya kusaidia na kisha kuwapa jina la amri.

577
00:47:34,340 --> 00:47:36,460
Na unaona GDB inatupa aina hii yote ya mambo.

578
00:47:36,460 --> 00:47:43,870
Ni anasema, "Kwa hoja hakuna, orodha ya kumi mistari zaidi baada ya au karibu na orodha ya awali.

579
00:47:43,870 --> 00:47:47,920
Orodha - orodha ya mistari kumi kabla - "

580
00:47:47,920 --> 00:47:52,960
Basi hebu jaribu kutumia minus orodha.

581
00:47:52,960 --> 00:47:57,000
Na kwamba orodha ya mistari 10 ya awali; unaweza kucheza karibu na orodha kidogo.

582
00:47:57,000 --> 00:48:02,330
Unaweza kufanya orodha, orodha -, unaweza hata kutoa orodha ya namba, kama orodha 8,

583
00:48:02,330 --> 00:48:07,500
na kutakuwa na kuorodhesha mistari 10 kuzunguka mstari 8.

584
00:48:07,500 --> 00:48:10,290
Na unaweza kuona nini kinaendelea hapa ni nimepata rahisi kama mwingine.

585
00:48:10,290 --> 00:48:13,980
Kama aina katika miamba CS50, ni Prints nje "Unaweza kupata A."

586
00:48:13,980 --> 00:48:16,530
Vinginevyo Prints nje "Unaweza kupata D."

587
00:48:16,530 --> 00:48:23,770
Bummer mji. Wote haki. Ndiyo?

588
00:48:23,770 --> 00:48:26,730
>> [Daniel] Basi nilipojaribu kufanya miamba CS50 bila quotes,

589
00:48:26,730 --> 00:48:29,290
inasema "Unaweza kupata D."

590
00:48:29,290 --> 00:48:32,560
Mimi zinahitajika quotes kwa kupata kazi, kwa nini ni hivyo?

591
00:48:32,560 --> 00:48:38,490
>> Yeah. Ni zinageuka kuwa wakati - hii ni mwingine furaha kidogo tidbit -

592
00:48:38,490 --> 00:48:47,900
wakati kukimbia mpango, kama sisi kukimbia na sisi aina katika miamba CS50,

593
00:48:47,900 --> 00:48:50,800
tu kama Danieli alikuwa akisema alifanya hivyo, na wewe hit Enter,

594
00:48:50,800 --> 00:48:52,870
bado anasema sisi kupata D.

595
00:48:52,870 --> 00:48:55,580
Na swali ni, nini hii?

596
00:48:55,580 --> 00:49:02,120
Na zinageuka kuwa wote terminal wetu na GDB Hazrat hizi mbili kama hoja tofauti.

597
00:49:02,120 --> 00:49:04,800
Kwa sababu wakati kuna nafasi, kwamba ni kumaanisha kama

598
00:49:04,800 --> 00:49:08,730
Hoja ya kwanza kumalizika; hoja ya pili ni kuhusu kuanza.

599
00:49:08,730 --> 00:49:13,260
njia ya kuchanganya wale mara mbili au sorry, ndani ya hoja moja,

600
00:49:13,260 --> 00:49:18,510
ni kutumia quotes.

601
00:49:18,510 --> 00:49:29,560
Hivyo sasa, kama sisi kuiweka katika quotes na kukimbia tena, sisi kupata A.

602
00:49:29,560 --> 00:49:38,780
Hivyo tu kwa kurejea, quotes hakuna, CS50 na miamba ni parsed kama hoja mbili tofauti.

603
00:49:38,780 --> 00:49:45,320
Pamoja na quotes, ni parsed kama moja hoja kabisa.

604
00:49:45,320 --> 00:49:53,070
>> Tunaweza kuona kwa breakpoint.

605
00:49:53,070 --> 00:49:54,920
Hadi sasa tumekuwa mbio mpango wetu, na imekuwa ni mbio

606
00:49:54,920 --> 00:49:58,230
mpaka ama ni seg makosa au hitilafu hits

607
00:49:58,230 --> 00:50:05,930
au mpaka ina exited na wote imekuwa kabisa faini.

608
00:50:05,930 --> 00:50:08,360
Hii ni lazima si kitu manufaa zaidi, kwa sababu wakati mwingine

609
00:50:08,360 --> 00:50:11,840
una kosa katika mpango wako, lakini si kosa na kusababisha segmentation.

610
00:50:11,840 --> 00:50:16,950
Si kusababisha mpango wako na kuacha au kitu kama hicho.

611
00:50:16,950 --> 00:50:20,730
njia ya kupata GDB pause mpango wako katika hatua fulani

612
00:50:20,730 --> 00:50:23,260
ni kuweka breakpoint.

613
00:50:23,260 --> 00:50:26,520
Unaweza ama kufanya hili kwa kuweka breakpoint juu ya jina kazi

614
00:50:26,520 --> 00:50:30,770
au unaweza kuweka breakpoint kwenye mstari fulani ya code.

615
00:50:30,770 --> 00:50:34,450
Mimi kama kuweka breakpoints juu ya majina ya kazi, kwa sababu - rahisi kukumbuka,

616
00:50:34,450 --> 00:50:37,700
na kama kweli kwenda katika na kubadili chanzo yako code juu kidogo,

617
00:50:37,700 --> 00:50:42,020
kisha breakpoint yako itakuwa kweli kukaa katika sehemu moja ndani ya code yako.

618
00:50:42,020 --> 00:50:44,760
Wakati kama wewe ni kutumia namba line, na idadi ya mstari kubadilika

619
00:50:44,760 --> 00:50:51,740
kwa sababu wewe kuongeza au kufuta baadhi ya kanuni, basi breakpoints yako yote kabisa Star up.

620
00:50:51,740 --> 00:50:58,590
Moja ya mambo ya kawaida mimi kufanya ni kuweka breakpoint juu ya kazi kuu.

621
00:50:58,590 --> 00:51:05,300
Mara nyingi mimi itabidi Boot juu GDB, mimi itabidi aina b kuu, hit Enter, na kwamba kutakuwa na kuweka breakpoint

622
00:51:05,300 --> 00:51:10,630
juu ya kazi kuu ambayo husema tu "pause mpango haraka kama wewe kuanza mbio,"

623
00:51:10,630 --> 00:51:17,960
na kwa njia hiyo, wakati mimi kuendesha programu yangu na, kusema, miamba CS50 kama mbili hoja

624
00:51:17,960 --> 00:51:24,830
na hit Enter, anapata kwa kazi kuu na ataacha haki katika mstari wa kwanza kabisa,

625
00:51:24,830 --> 00:51:30,620
haki kabla ya kutathmini kazi strcmp.

626
00:51:30,620 --> 00:51:34,940
>> Tangu mimi nina paused, sasa naweza kuanza mucking karibu na kuona nini kinaendelea

627
00:51:34,940 --> 00:51:40,250
na wote wa vigezo mbalimbali ambayo ni kupita katika mpango wangu.

628
00:51:40,250 --> 00:51:43,670
Hapa naweza magazeti nje argc na kuona nini kinaendelea.

629
00:51:43,670 --> 00:51:50,030
Kuona kwamba argc ni 3, kwa sababu ni got 3 maadili tofauti ndani yake.

630
00:51:50,030 --> 00:51:54,060
Ni got jina la mpango, ni got hoja kwanza na hoja ya pili.

631
00:51:54,060 --> 00:52:09,330
Tunaweza magazeti wale nje kwa kuangalia argv [0], argv [1], na argv [2].

632
00:52:09,330 --> 00:52:12,030
Hivyo sasa unaweza pia kuona nini wito huu strcmp ataenda kushindwa,

633
00:52:12,030 --> 00:52:21,650
kwa sababu unaweza kuona kwamba hawakuwa wameigawanya CS50 na miamba katika hoja mbili tofauti.

634
00:52:21,650 --> 00:52:27,250
Katika hatua hii, mara moja umefanya hit breakpoint, unaweza kuendelea na hatua ya kupitia mpango wako

635
00:52:27,250 --> 00:52:32,920
mstari kwa mstari, kinyume na kuanza programu yako tena.

636
00:52:32,920 --> 00:52:35,520
Hivyo kama wewe hawataki kuanza programu yako tena na kuendelea tu kutoka hapa,

637
00:52:35,520 --> 00:52:41,970
unaweza kutumia amri kuendelea na kuendelea kukimbia mpango wa mwisho.

638
00:52:41,970 --> 00:52:45,010
Tu kama ilivyokuwa hapa.

639
00:52:45,010 --> 00:52:54,880
Hata hivyo, kama mimi kuanzisha upya mpango, miamba CS50, ni hits breakpoint yangu tena,

640
00:52:54,880 --> 00:52:59,670
na wakati huu, kama mimi sitaki tu kwenda njia zote wengine wa mpango,

641
00:52:59,670 --> 00:53:08,040
Naweza kutumia amri ya pili, ambayo mimi pia abbreviate na n.

642
00:53:08,040 --> 00:53:12,960
Na hii hatua kupitia line mpango na mstari.

643
00:53:12,960 --> 00:53:17,530
Hivyo unaweza kuangalia kama mambo nitafanya, vigezo kama mabadiliko, kama mambo kupata updated.

644
00:53:17,530 --> 00:53:21,550
Ambayo ni pretty nice.

645
00:53:21,550 --> 00:53:26,570
nyingine kitu baridi ni badala ya kurudia amri sawa juu na juu tena na tena,

646
00:53:26,570 --> 00:53:30,670
kama wewe tu hit Enter - hivyo unaweza kuona hapa mimi si typed katika kitu chochote -

647
00:53:30,670 --> 00:53:33,780
kama mimi tu hit Enter, itakuwa kurudia amri ya awali,

648
00:53:33,780 --> 00:53:36,900
au uliopita GDB amri kwamba mimi tu ya kuweka in

649
00:53:36,900 --> 00:53:56,000
Naweza kushika kupiga Ingiza na itabidi kuweka wanazidi kupitia line code yangu na mstari.

650
00:53:56,000 --> 00:53:59,310
Napenda moyo guys kwenda kuangalia nje ya mipango Buggy nyingine pia.

651
00:53:59,310 --> 00:54:01,330
Hatuna muda wa kupata njia ya wote leo katika sehemu.

652
00:54:01,330 --> 00:54:05,890
chanzo code ni huko, hivyo unaweza aina ya kuona nini kinaendelea

653
00:54:05,890 --> 00:54:07,730
nyuma ya pazia kama wewe kupata kweli kukwama,

654
00:54:07,730 --> 00:54:11,940
lakini kwa uchache sana, tu mazoezi ya booting up GDB,

655
00:54:11,940 --> 00:54:13,940
mbio mpango mpaka inavunja juu yenu,

656
00:54:13,940 --> 00:54:18,260
kupata backtrace, kuhesabia nje nini kazi ajali alikuwa katika,

657
00:54:18,260 --> 00:54:24,450
nini mstari huu ulikuwa katika, uchapishaji nje maadili baadhi variable,

658
00:54:24,450 --> 00:54:30,140
hivyo tu kupata kujisikia kwa ajili yake, kwa sababu kwamba itakuwa kweli kukusaidia kwenda mbele.

659
00:54:30,140 --> 00:54:36,340
Katika hatua hii, sisi ni kwenda nje ya kujiondoa GDB, ambayo huna kutumia kujiondoa au tu q.

660
00:54:36,340 --> 00:54:40,460
Kama mpango wako ni katikati ya mbio bado, na ina si exited,

661
00:54:40,460 --> 00:54:43,510
itakuwa daima kukuuliza, "Je una uhakika kweli unataka kuacha?"

662
00:54:43,510 --> 00:54:48,770
Unaweza tu hit ndiyo.

663
00:54:48,770 --> 00:54:55,250
>> Sasa sisi ni kwenda kuangalia tatizo ijayo tuna, ambayo ni programu ya paka.

664
00:54:55,250 --> 00:54:59,880
Kama wewe kuangalia mfupi juu ya imetuma na mabomba, utaona kwamba Tommy anatumia programu hii ya

665
00:54:59,880 --> 00:55:07,540
kwamba kimsingi Prints pato yote ya faili screen.

666
00:55:07,540 --> 00:55:12,660
Hivyo kama mimi kukimbia paka, hii ni kweli mpango wa kujengwa katika appliance,

667
00:55:12,660 --> 00:55:16,860
na kama una Macs unaweza kufanya hili juu ya Mac yako pia, kama wewe kufungua terminal.

668
00:55:16,860 --> 00:55:25,630
Na sisi - paka, hebu sema, cp.c, na hit Enter.

669
00:55:25,630 --> 00:55:29,640
Nini hii alivyofanya, kama sisi kitabu juu kidogo na kuona ambapo sisi mbio line,

670
00:55:29,640 --> 00:55:40,440
au ambapo sisi mbio amri paka, ni literally tu kuchapishwa yaliyomo ya cp.c na screen zetu.

671
00:55:40,440 --> 00:55:44,140
Tunaweza kukimbia tena na unaweza kuweka katika files nyingi pamoja.

672
00:55:44,140 --> 00:55:49,880
Hivyo unaweza kufanya paka cp.c, na kisha tunaweza pia concatenate faili cat.c,

673
00:55:49,880 --> 00:55:53,250
ambayo ni mpango sisi ni juu ya kuandika,

674
00:55:53,250 --> 00:55:58,140
na kutakuwa na magazeti files wote nyuma kwa nyuma na screen zetu.

675
00:55:58,140 --> 00:56:05,490
Hivyo kama sisi kitabu juu kidogo, tunaona kwamba wakati sisi mbio hii cp.c paka, cat.c,

676
00:56:05,490 --> 00:56:17,110
kwanza ni kuchapishwa faili linganisha, na kisha chini yake, kuchapishwa faili cat.c haki ya chini hapa.

677
00:56:17,110 --> 00:56:19,650
Sisi ni kwenda kutumia hii kupata tu miguu yetu mvua.

678
00:56:19,650 --> 00:56:25,930
Kucheza karibu na uchapishaji rahisi terminal, kuona jinsi kazi.

679
00:56:25,930 --> 00:56:39,170
Kama wewe guys kufungua na gedit cat.c, hit Enter,

680
00:56:39,170 --> 00:56:43,760
unaweza kuona kwamba mpango tuko tayari kuandika.

681
00:56:43,760 --> 00:56:48,980
Tumekuwa pamoja hii nice boiler sahani, hivyo hatuna kutumia muda kuandika nje kwamba wote.

682
00:56:48,980 --> 00:56:52,310
Sisi pia kuangalia idadi ya hoja kupita in

683
00:56:52,310 --> 00:56:56,910
Sisi magazeti nje nzuri ya matumizi ya ujumbe.

684
00:56:56,910 --> 00:57:00,950
>> Hii ni aina ya kitu tena kuwa, kama tumekuwa kuzungumza juu,

685
00:57:00,950 --> 00:57:04,490
kwa karibu ni kama kumbukumbu ya misuli.

686
00:57:04,490 --> 00:57:07,190
Kumbuka tu kuendelea kufanya aina moja ya mambo

687
00:57:07,190 --> 00:57:11,310
na daima uchapishaji nje baadhi ya aina ya ujumbe kusaidia

688
00:57:11,310 --> 00:57:17,670
ili watu kujua jinsi ya kuendesha programu yako.

689
00:57:17,670 --> 00:57:21,630
Na paka, ni pretty rahisi; sisi ni kwenda tu kwenda kwa yote ya hoja mbalimbali

690
00:57:21,630 --> 00:57:24,300
kwamba walikuwa kupita kwa programu yetu, na sisi ni kwenda magazeti

691
00:57:24,300 --> 00:57:29,950
yaliyomo yao nje na screen moja kwa wakati mmoja.

692
00:57:29,950 --> 00:57:35,670
Ili magazeti files nje screen, tunakwenda kufanya kitu sawa sana

693
00:57:35,670 --> 00:57:38,120
kwa nini tulifanya mwisho wa chemsha bongo.

694
00:57:38,120 --> 00:57:45,350
Wakati wa mwisho wa jaribio, kwamba kuajiri mpango, tulikuwa na kufungua faili,

695
00:57:45,350 --> 00:57:48,490
na kisha tulikuwa na magazeti hayo.

696
00:57:48,490 --> 00:57:54,660
Katika kesi hii, sisi ni kwenda kufungua faili, na sisi ni kwenda kusoma kutoka humo badala yake.

697
00:57:54,660 --> 00:58:00,630
Kisha tunakwenda magazeti, badala ya SVG, tunakwenda magazeti kwa screen.

698
00:58:00,630 --> 00:58:05,830
Hivyo uchapishaji na screen ve yote kufanyika kabla na printf.

699
00:58:05,830 --> 00:58:08,290
Hivyo si kwamba pia mambo.

700
00:58:08,290 --> 00:58:12,190
Lakini kusoma faili ni aina ya weird.

701
00:58:12,190 --> 00:58:17,300
Tutaweza kwenda kupitia kidogo kidogo kwa wakati.

702
00:58:17,300 --> 00:58:20,560
Kama wewe guys kurejea tatizo kwamba mwisho juu ya chemsha bongo yako, tatizo 33,

703
00:58:20,560 --> 00:58:27,280
mstari wa kwanza kwamba sisi ni kwenda kufanya hapa, kufungua faili, ni sawa na sisi alivyofanya huko.

704
00:58:27,280 --> 00:58:36,370
Hivyo Stella, ni nini kwamba kuangalia line kama, wakati sisi kufungua faili?

705
00:58:36,370 --> 00:58:47,510
[Stella] Capital JALADA *, faili - >> Sawa. >> - Ni sawa na fopen. >> Yup.

706
00:58:47,510 --> 00:58:55,980
Ambayo katika kesi hii ni? Ni katika maoni.

707
00:58:55,980 --> 00:59:06,930
>> Ni katika maoni? argv [i] na r?

708
00:59:06,930 --> 00:59:11,300
>> Hasa. Haki juu. Hivyo ni Stella kabisa kulia.

709
00:59:11,300 --> 00:59:13,720
Hii ni nini mstari inaonekana kama.

710
00:59:13,720 --> 00:59:19,670
Sisi ni kwenda kupata mkondo faili variable, kuhifadhi katika * JALADA, hivyo wote kofia,

711
00:59:19,670 --> 00:59:25,720
JALADA, *, na jina la kutofautiana hii itakuwa faili.

712
00:59:25,720 --> 00:59:32,250
Tunaweza kuuita chochote sisi kama. Tunaweza kuuita first_file, au file_i, chochote tunatarajia.

713
00:59:32,250 --> 00:59:37,590
Na kisha jina la faili ilipitishwa katika juu ya mstari amri kwa mpango huu.

714
00:59:37,590 --> 00:59:44,450
Hivyo ni kuhifadhiwa katika argv [i,] na kisha tunakwenda kufungua faili hii katika mode kusoma.

715
00:59:44,450 --> 00:59:48,100
Sasa kwa kuwa tumekuwa kufunguliwa faili, nini kitu sisi daima kuwa kukumbuka kufanya

716
00:59:48,100 --> 00:59:52,230
wakati wowote tumekuwa kufunguliwa faili? Funga.

717
00:59:52,230 --> 00:59:57,220
Hivyo Missy, jinsi gani sisi karibu faili?

718
00:59:57,220 --> 01:00:01,020
[Missy] fclose (faili) >> fclose (faili). Hasa.

719
01:00:01,020 --> 01:00:05,340
Mkuu. Sawa. Kama sisi kuangalia hii kufanya comment haki hapa,

720
01:00:05,340 --> 01:00:11,940
inasema, "Open argv [i] na magazeti yaliyomo yake kwa stdout."

721
01:00:11,940 --> 01:00:15,460
>> Darasa la nje ni jina weird. Stdout ni njia yetu ya kusema

722
01:00:15,460 --> 01:00:22,880
tunataka magazeti kwa terminal; tunataka magazeti kwa mkondo kiwango pato.

723
01:00:22,880 --> 01:00:26,450
Tunaweza kweli kujikwamua ya maoni hayo hapa hapa.

724
01:00:26,450 --> 01:00:36,480
Mimi naenda nakala yake na kuuweka tangu kwamba ni nini sisi alivyofanya.

725
01:00:36,480 --> 01:00:41,290
Katika hatua hii, sasa tuna kusoma kidogo faili kidogo.

726
01:00:41,290 --> 01:00:46,300
Tumekuwa kujadiliwa michache ya njia za files kusoma.

727
01:00:46,300 --> 01:00:51,830
Ambayo ndio ni favorites yako hadi sasa?

728
01:00:51,830 --> 01:00:57,960
Ambayo njia umeona au unakumbuka, kusoma files?

729
01:00:57,960 --> 01:01:04,870
[Daniel] fread? >> Fread? Hivyo fread ni moja. Jimmy, unajua wengine yoyote?

730
01:01:04,870 --> 01:01:12,150
[Jimmy] No >> Sawa. Nope. Charlotte? Alexander? Yoyote ya wengine? Sawa.

731
01:01:12,150 --> 01:01:20,740
Hivyo wale wengine ni fgetc, ni moja kwamba tutaweza matumizi mengi.

732
01:01:20,740 --> 01:01:26,410
Kuna pia fscanf; guys kuona ruwaza hapa?

733
01:01:26,410 --> 01:01:29,170
Wao wote kuanza na f. Kitu cha kufanya na faili.

734
01:01:29,170 --> 01:01:35,260
Kuna fread, fgetc, fscanf. Haya yote ni ya kazi ya kusoma.

735
01:01:35,260 --> 01:01:49,120
Kwa kuandika tuna fwrite, tuna fputc badala ya fgetc.

736
01:01:49,120 --> 01:01:58,250
Sisi pia fprintf kama tuliona juu ya chemsha bongo.

737
01:01:58,250 --> 01:02:01,680
Tangu hii ni tatizo kwamba inahusisha kusoma kutoka faili,

738
01:02:01,680 --> 01:02:04,940
tunakwenda kutumia moja ya kazi hizi tatu.

739
01:02:04,940 --> 01:02:10,890
Sisi siyo kwenda kutumia kazi hizo chini hapa.

740
01:02:10,890 --> 01:02:14,880
Kazi hizi ni wote kupatikana katika maktaba standard I / O.

741
01:02:14,880 --> 01:02:17,510
Hivyo kama wewe kuangalia juu ya mpango huu,

742
01:02:17,510 --> 01:02:24,110
unaweza kuona kwamba tumekuwa tayari ni pamoja na faili header kwa ajili ya maktaba standard I / O.

743
01:02:24,110 --> 01:02:27,120
Kama tunataka kufikiri ambayo moja tunataka kutumia,

744
01:02:27,120 --> 01:02:29,690
tunaweza daima kufungua kurasa mtu.

745
01:02:29,690 --> 01:02:34,350
Hivyo tunaweza aina mtu stdio

746
01:02:34,350 --> 01:02:43,180
na kusoma yote juu ya pembejeo stdio na kazi pato katika C.

747
01:02:43,180 --> 01:02:49,870
Na sisi tayari kuona oh, kuangalia. Ni kutaja fgetc, kutajwa fputc.

748
01:02:49,870 --> 01:02:57,220
Hivyo unaweza drill chini kidogo na kuangalia, kusema, fgetc

749
01:02:57,220 --> 01:03:00,060
na kuangalia mtu ukurasa wake.

750
01:03:00,060 --> 01:03:03,430
Unaweza kuona kwamba huenda pamoja na rundo zima la kazi nyingine:

751
01:03:03,430 --> 01:03:12,640
fgetc, fgets, getc, getchar, anapata, ungetc, na mchango wake wa wahusika na masharti.

752
01:03:12,640 --> 01:03:19,180
Hivyo hii ni jinsi sisi kusoma katika wahusika na masharti kutoka files kutoka pembejeo kiwango,

753
01:03:19,180 --> 01:03:21,990
ambayo kimsingi ni kutoka kwa mtumiaji.

754
01:03:21,990 --> 01:03:24,780
Na hii ni jinsi sisi kufanya hivyo katika C. halisi

755
01:03:24,780 --> 01:03:30,850
Hivyo hii si kutumia GetString na kazi GetChar

756
01:03:30,850 --> 01:03:36,840
kwamba sisi kutumika kutoka maktaba CS50.

757
01:03:36,840 --> 01:03:39,710
Sisi ni kwenda kufanya tatizo hili katika michache ya njia

758
01:03:39,710 --> 01:03:43,430
hivyo kwamba unaweza kuona njia mbili tofauti ya kufanya hivyo.

759
01:03:43,430 --> 01:03:48,490
Wote kazi fread kwamba Danieli zilizotajwa na fgetc ni nzuri njia ya kufanya hivyo.

760
01:03:48,490 --> 01:03:53,790
Nadhani fgetc ni rahisi kidogo, kwa sababu tu ana, kama unaweza kuona,

761
01:03:53,790 --> 01:03:59,660
moja hoja, * JALADA kwamba sisi ni kujaribu kusoma tabia kutoka,

762
01:03:59,660 --> 01:04:02,740
na kurudi thamani yake ni int.

763
01:04:02,740 --> 01:04:05,610
Na hii ni utata kidogo, haki?

764
01:04:05,610 --> 01:04:11,450
>> Kwa sababu sisi ni kupata tabia, hivyo kwa nini hana hii kurudi Char?

765
01:04:11,450 --> 01:04:18,700
You guys kuwa na mawazo yoyote juu ya nini hii ili asirudi Char?

766
01:04:18,700 --> 01:04:25,510
[Missy majibu, unintelligible] >> Yeah. Hivyo ni Missy kabisa kulia.

767
01:04:25,510 --> 01:04:31,570
Kama ni ASCII, basi integer hii inaweza mapped Char halisi.

768
01:04:31,570 --> 01:04:33,520
Inaweza kuwa tabia ASCII, na hiyo ni haki.

769
01:04:33,520 --> 01:04:36,220
Hiyo ni nini hasa kinatokea.

770
01:04:36,220 --> 01:04:39,190
Sisi ni kutumia int kwa sababu tu ana bits zaidi.

771
01:04:39,190 --> 01:04:44,750
Ni kubwa kuliko Char; Char yetu pekee ya bits 8, kwamba 1 Byte juu ya mashine yetu 32-bit.

772
01:04:44,750 --> 01:04:48,520
Na int ina thamani yote ka 4 'wa nafasi.

773
01:04:48,520 --> 01:04:50,940
Na zinageuka kuwa njia fgetc kazi,

774
01:04:50,940 --> 01:04:53,940
kama sisi kitabu chini katika Synopsis wetu katika ukurasa huu mtu kidogo kidogo,

775
01:04:53,940 --> 01:05:05,000
kitabu njia yote chini. Ni zinageuka kuwa wao kutumia thamani hii maalum iitwayo EOF.

776
01:05:05,000 --> 01:05:09,640
Ni mara kwa mara maalum kama thamani ya kurudi kwa kazi fgetc

777
01:05:09,640 --> 01:05:14,570
wakati wowote wewe hit mwisho wa faili au kama wewe kupata kosa.

778
01:05:14,570 --> 01:05:18,170
Na zinageuka kuwa kufanya kulinganisha hizi na EOF vizuri,

779
01:05:18,170 --> 01:05:24,060
unataka kuwa na kwamba kiasi ya ziada ya habari kwamba una katika int

780
01:05:24,060 --> 01:05:28,420
kinyume na kutumia variable Char.

781
01:05:28,420 --> 01:05:32,130
Hata ingawa fgetc Inazidi tabia kutoka faili,

782
01:05:32,130 --> 01:05:38,450
unataka kukumbuka kwamba ni kurudi kitu ambacho ni cha int aina na wewe.

783
01:05:38,450 --> 01:05:41,360
Kwamba alisema, ni haki rahisi kutumia.

784
01:05:41,360 --> 01:05:44,960
Ni kwenda kutupa tabia, hivyo wote sisi kufanya ni kuendelea kuuliza faili,

785
01:05:44,960 --> 01:05:48,440
"Nipe tabia ijayo, nipe tabia ijayo, nipe tabia ijayo,"

786
01:05:48,440 --> 01:05:51,400
mpaka sisi kupata mwisho wa faili.

787
01:05:51,400 --> 01:05:54,730
Na kwamba kuvuta katika tabia moja kwa wakati mmoja kutoka faili yetu,

788
01:05:54,730 --> 01:05:56,250
na basi tunaweza kufanya chochote sisi kama na hayo.

789
01:05:56,250 --> 01:06:00,160
Tunaweza kukihifadhi, tunaweza kuongeza kwa kamba, tunaweza magazeti nje.

790
01:06:00,160 --> 01:06:04,630
Je yoyote ya kwamba.

791
01:06:04,630 --> 01:06:09,600
>> Zooming nyuma nje na kurejea kwa programu yetu cat.c,

792
01:06:09,600 --> 01:06:16,170
kama sisi ni kwenda kutumia fgetc,

793
01:06:16,170 --> 01:06:21,710
jinsi tunavyoweza mbinu line hii ya pili ya kificho?

794
01:06:21,710 --> 01:06:26,020
Sisi ni kwenda kutumia - fread kufanya kitu tofauti kidogo.

795
01:06:26,020 --> 01:06:32,600
Na wakati huu, tuko tu kwenda kutumia fgetc kupata moja tabia kwa wakati.

796
01:06:32,600 --> 01:06:40,910
Kuchakata faili nzima, nini kinaweza tuna kufanya?

797
01:06:40,910 --> 01:06:44,030
Ngapi wahusika ni pale katika faili?

798
01:06:44,030 --> 01:06:47,390
Kuna mengi. Hivyo pengine wanataka kupata moja

799
01:06:47,390 --> 01:06:49,860
na kisha kupata mwingine na kupata mwingine na kupata mwingine.

800
01:06:49,860 --> 01:06:53,330
Ni aina gani ya algorithm unafikiri sisi tupate kuwa na matumizi ya hapa?

801
01:06:53,330 --> 01:06:55,470
Ni aina gani ya -? [Alexander] A kwa kitanzi? >> Hasa.

802
01:06:55,470 --> 01:06:57,500
Baadhi ya aina ya kitanzi.

803
01:06:57,500 --> 01:07:03,380
kwa kitanzi ni kweli mkuu, katika kesi hii.

804
01:07:03,380 --> 01:07:08,620
Na kama wewe walikuwa wakisema, inaonekana kama unataka kitanzi juu ya faili nzima,

805
01:07:08,620 --> 01:07:11,820
kupata tabia kwa wakati.

806
01:07:11,820 --> 01:07:13,850
Mapendekezo yoyote juu ya nini kuwa ili kuangalia kama?

807
01:07:13,850 --> 01:07:22,090
[Alexander, unintelligible]

808
01:07:22,090 --> 01:07:30,050
>> Sawa, niambie tu katika Kiingereza unachojaribu kufanya? [Alexander, unintelligible]

809
01:07:30,050 --> 01:07:36,270
Hivyo katika kesi hii, inaonekana kama sisi ni kujaribu tu kitanzi juu ya faili nzima.

810
01:07:36,270 --> 01:07:45,330
[Alexander] Hivyo i <ukubwa wa int? >> Ukubwa wa -?

811
01:07:45,330 --> 01:07:49,290
Nadhani ukubwa wa faili, haki? kawaida - we'll andika tu kama hii.

812
01:07:49,290 --> 01:07:57,470
Ukubwa wa faili kwa wakati kuwa, i + +.

813
01:07:57,470 --> 01:08:04,610
Hivyo ni zinageuka kuwa njia hii huna kutumia fgetc, na hii ni mpya,

814
01:08:04,610 --> 01:08:10,460
ni kwamba hakuna njia rahisi tu kupata ukubwa wa faili

815
01:08:10,460 --> 01:08:16,979
pamoja na "sizeof" aina ya kujenga kwamba ve kuona mbele.

816
01:08:16,979 --> 01:08:20,910
Wakati sisi kutumia kwamba kazi fgetc, sisi ni kuanzisha aina fulani ya

817
01:08:20,910 --> 01:08:29,069
mpya, funky syntax kwa hii kwa kitanzi, ambapo badala ya kutumia tu counter ya msingi

818
01:08:29,069 --> 01:08:33,920
kwenda tabia na tabia, sisi ni kwenda kuvuta moja tabia kwa wakati,

819
01:08:33,920 --> 01:08:37,120
mhusika mmoja kwa wakati, na njia ya sisi kujua tuko mwishoni

820
01:08:37,120 --> 01:08:41,290
si wakati tumekuwa kuhesabiwa idadi fulani ya wahusika,

821
01:08:41,290 --> 01:08:49,939
lakini wakati sisi tabia kujiondoa ni kwamba mwisho wa tabia maalum faili.

822
01:08:49,939 --> 01:08:58,689
Hivyo tunaweza kufanya hivyo kwa - Mimi wito huu ch, na tunakwenda initialize ni

823
01:08:58,689 --> 01:09:08,050
na wito wetu wa kwanza kupata tabia ya kwanza nje ya faili.

824
01:09:08,050 --> 01:09:14,979
Hivyo hii sehemu haki hapa, hii ni kwenda kupata tabia nje ya faili

825
01:09:14,979 --> 01:09:20,840
na kuhifadhi katika ch kutofautiana.

826
01:09:20,840 --> 01:09:25,420
Sisi ni kwenda kuendelea kufanya hili mpaka sisi kupata mwisho wa faili,

827
01:09:25,420 --> 01:09:41,170
ambayo sisi kufanya kwa kupima kwa ajili ya tabia si kuwa sawa na tabia ya kuwa maalum EOF.

828
01:09:41,170 --> 01:09:48,750
Na kisha badala ya kufanya ch + +, ambayo ingekuwa tu increment thamani,

829
01:09:48,750 --> 01:09:52,710
hivyo kama sisi kusoma nje ya SVG, mji mkuu, wanasema,

830
01:09:52,710 --> 01:09:56,810
ch + + atatupa b, na kisha tunatarajia kupata c na kisha d.

831
01:09:56,810 --> 01:09:59,310
Hiyo ni wazi si nini tunataka. Tunachotaka hapa

832
01:09:59,310 --> 01:10:05,830
katika kidogo hii ya mwisho ni tunataka kupata tabia ijayo kutoka faili.

833
01:10:05,830 --> 01:10:09,500
>> Hivyo jinsi tunavyoweza kupata tabia ijayo kutoka faili?

834
01:10:09,500 --> 01:10:13,470
Jinsi gani sisi kupata tabia ya kwanza kutoka faili?

835
01:10:13,470 --> 01:10:17,200
[Mwanafunzi] fgetfile? >> Fgetc, au, sorry, ungekuwa kabisa kulia.

836
01:10:17,200 --> 01:10:20,470
Mimi misspelled ni haki pale. Hivyo yeah.

837
01:10:20,470 --> 01:10:26,240
Hapa badala ya kufanya ch + +,

838
01:10:26,240 --> 01:10:29,560
sisi ni tu kwenda kuwaita fgetc (faili) tena

839
01:10:29,560 --> 01:10:39,180
na kuhifadhi matokeo katika variable yetu sawa ch.

840
01:10:39,180 --> 01:10:43,730
[Mwanafunzi swali, unintelligible]

841
01:10:43,730 --> 01:10:52,390
>> Hii ni wapi hawa * JALADA guys ni maalum.

842
01:10:52,390 --> 01:10:59,070
njia ya wao kufanya kazi ni wao - wakati wa kwanza kufungua - wakati wewe kwanza kufanya wito fopen,

843
01:10:59,070 --> 01:11:04,260
* JALADA ufanisi mtumishi kama pointer mwanzo ya faili.

844
01:11:04,260 --> 01:11:12,830
Na kisha kila wakati wewe piga fgetc, ni hatua moja tabia kupitia faili.

845
01:11:12,830 --> 01:11:23,280
Hiyo wakati wowote wewe piga hii, wewe incrementing pointer faili na tabia moja.

846
01:11:23,280 --> 01:11:26,210
Na wakati wewe fgetc tena, wewe ni kusonga ni mwingine tabia

847
01:11:26,210 --> 01:11:28,910
na mwingine tabia na mwingine tabia na mwingine tabia.

848
01:11:28,910 --> 01:11:32,030
[Mwanafunzi swali, unintelligible] >> Na that's - yeah.

849
01:11:32,030 --> 01:11:34,810
Ni aina ya uchawi huu chini ya Hood.

850
01:11:34,810 --> 01:11:37,930
Wewe tu kuweka incrementing kupitia.

851
01:11:37,930 --> 01:11:46,510
Katika hatua hii, uko na uwezo wa kweli kazi pamoja na tabia.

852
01:11:46,510 --> 01:11:52,150
Hivyo jinsi tunavyoweza magazeti hii nje ya screen, sasa?

853
01:11:52,150 --> 01:11:58,340
Tunaweza kutumia moja printf kitu kwamba sisi kutumika kabla.

854
01:11:58,340 --> 01:12:00,330
Kwamba sisi tumekuwa kutumia wote muhula.

855
01:12:00,330 --> 01:12:05,450
Tunaweza kuwaita printf,

856
01:12:05,450 --> 01:12:21,300
na tunaweza kupita katika tabia kama hiyo.

857
01:12:21,300 --> 01:12:27,430
Njia nyingine ya kufanya hivyo ni badala ya kutumia printf na baada ya kufanya hii string format,

858
01:12:27,430 --> 01:12:29,490
tunaweza pia kutumia moja ya kazi nyingine.

859
01:12:29,490 --> 01:12:40,090
Tunaweza kutumia fputc, ambayo Prints tabia ya screen,

860
01:12:40,090 --> 01:12:52,580
isipokuwa kama tunaangalia fputc - ngoja zoom nje kidogo.

861
01:12:52,580 --> 01:12:56,430
Sisi kuona nini ni nzuri ni inachukua katika tabia ya kuwa sisi kusoma nje kwa kutumia fgetc,

862
01:12:56,430 --> 01:13:05,100
lakini basi tuna kuwapa mkondo wa magazeti ya.

863
01:13:05,100 --> 01:13:11,850
Tunaweza pia kutumia kazi putchar, ambayo kuweka moja kwa moja na nje ya kiwango.

864
01:13:11,850 --> 01:13:16,070
Hivyo kuna rundo zima ya chaguzi mbalimbali kwamba tunaweza kutumia kwa ajili ya uchapishaji.

865
01:13:16,070 --> 01:13:19,580
Wao ni wote katika maktaba standard I / O.

866
01:13:19,580 --> 01:13:25,150
Kila unataka na magazeti - hivyo printf, kwa default, itakuwa magazeti kwa kiwango maalum nje mkondo,

867
01:13:25,150 --> 01:13:27,910
ambayo ni stdout kwamba.

868
01:13:27,910 --> 01:13:41,300
Hivyo tunaweza tu rejea ni kama aina ya thamani hii uchawi, stdout katika hapa.

869
01:13:41,300 --> 01:13:48,410
Lo. Weka semicolon nje.

870
01:13:48,410 --> 01:13:52,790
>> Hii ni mengi ya habari mpya, funky katika hapa.

871
01:13:52,790 --> 01:13:58,600
mengi ya hii ni nahau au msemo wenye sana, kwa maana kwamba hii ni code

872
01:13:58,600 --> 01:14:05,700
yaliyoandikwa kwa njia hii tu kwa sababu ni safi kusoma, rahisi kusoma.

873
01:14:05,700 --> 01:14:11,520
Kuna njia nyingi tofauti ya kufanya hivyo, wengi tofauti kazi unaweza kutumia,

874
01:14:11,520 --> 01:14:14,680
lakini sisi huwa tu kufuata ruwaza hizi sawa juu na juu.

875
01:14:14,680 --> 01:14:20,180
Hivyo msishangae kama wewe kuona kanuni kama hii kuja tena na tena.

876
01:14:20,180 --> 01:14:25,690
Wote haki. Katika hatua hii, tunahitaji kuvunja kwa siku.

877
01:14:25,690 --> 01:14:31,300
Shukrani kwa kuja. Shukrani kwa ajili ya kuangalia kama uko online. Na tutaweza kuona wewe wiki ijayo.

878
01:14:31,300 --> 01:14:33,890
[CS50.TV]