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[Powered by Google Translate] [Walkthrough - Tatizo Set 2]

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[Zamyla Chan - Chuo Kikuu cha Harvard]

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[Hii ni CS50. CS50.TV]

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Wote haki. Hello, kila mtu, na kuwakaribisha kwa walkthrough 2.

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Kwanza, nataka kumpongeza wewe kwa ajili ya kumaliza pset 1.

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Najua kwamba inaweza kuwa kidogo ngumu kwa baadhi yenu,

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wangeweza kompyuta yako kwanza mpango kwamba aliandika,

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lakini kumbuka tu kwamba mwishoni mwa huu, wakati wewe kuangalia nyuma katika mwisho wa muhula,

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utasikia kuangalia pset 1 na itabidi kusema, "Hey, mimi wangefanya kwamba katika dakika 5."

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Basi jua na imani kwamba katika mwisho wa hii wewe utakuwa dhahiri kupata pset 1 rahisi kabisa.

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Lakini kwa sasa ni accomplishment kubwa, na pongezi kwa ajili ya kupata kufanyika.

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Sasa, pia kumbuka haraka kabla ya sisi kupata katika nyama ya walkthrough.

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Mimi nataka tu kufanya note haraka kwamba mimi wakati mwingine si muda wa kutosha

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wakati walkthroughs kupitia kila njia moja ya kufanya seti tatizo

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na badala tu labda kuzingatia 1 au 2 aina ya utekelezaji,

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njia ambazo unaweza kufanya.

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Lakini kwamba si kusema kwamba wewe ni haramu kutoka kufanya hivyo kwa njia nyingine.

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Kuna mara nyingi, kama na sayansi ya kompyuta, njia mbalimbali za kufanya mambo,

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na hivyo dhahiri kujisikia huru kutumia aina mbalimbali za ufumbuzi kuliko nipate kuwasilishwa.

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[Pset 2: Crypto - Zamyla Chan - zamyla@cs50.net]

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[Pset2 - 0. Sehemu ya Maswali - 1. Caesar - 2. Vigenere]

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Wote haki. Hivyo tatizo kuweka 2: Crypto ni moja ya kujifurahisha.

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Tena, kwa pset kila itabidi kuanza na sehemu ya maswali

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ambayo inaenda kuwa uliofanywa katika sehemu yako na wenzako kupewa mafundisho.

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Sisi si kwenda na kwenda kwa njia hizi juu ya walkthrough,

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lakini wao dhahiri kusaidia kukamilisha pset.

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Hivyo sehemu ya kwanza ya kuweka tatizo ni Kaisari.

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Na hivyo katika Kaisari mtu atapita wewe muhimu na integer,

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na utakuwa encrypt kamba ya maandishi kwamba wao kutoa

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na kuwapa nyuma kitu uliosimbwa.

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Kama mtu yeyote watched Story Krismasi, kuna mfano wa kwamba kuna.

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Kisha sehemu ya pili ya kuweka tatizo ni Vigenere,

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ambayo ni ya juu zaidi encryption mbinu.

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Na hivyo tunakwenda encipher kipande cha maandishi,

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ila badala tu na integer moja, sisi ni kweli kwenda encode ni

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na Keyword kwamba mtumiaji atatupatia.

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Sawa, hivyo chombo kwanza katika leo toolbox ni kweli kwenda kuwa uppdatering appliance.

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Juu ya bodi ya majadiliano tunataka kuona vitu kama, "Kwa nini si kazi hii?"

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"Kwa nini si Kuwasilisha 50 kazi?"

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na mara nyingi ufumbuzi ni kweli tu kwa update appliance yako.

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Na hivyo kama wewe kukimbia tu katika dirisha terminal katika Sudo appliance yako yum-y -

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hiyo ni bendera ya kusema ndiyo, update kila kitu - update,

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kisha appliance wako update kama haja kuwa.

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Na haina madhara kama tayari ni saa toleo ya hivi karibuni zaidi ya appliance.

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Basi itakuwa tu kusema hakuna masasisho mapya yanapatikana na unaweza kuendelea kufanya kazi pamoja.

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Lakini hii ni nzuri na nitafanya hata kila wakati kwamba kufungua appliance

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kwa sababu sisi ni bado sana -

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wakati mwingine kama sisi kuja katika mdudu - fixing katika appliance.

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Hivyo kuhakikisha kwamba una toleo ya hivi karibuni zaidi ya appliance

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na kukimbia kwamba update huko.

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Wote haki. Hivyo tangu sisi ni kushughulika na barua na kubadilisha, enciphering mambo,

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tunakwenda kweli unataka kuwa bora na marafiki pamoja na chati yetu ASCII.

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Kuna wale wengi online, kama wewe kupata. Labda hata kufanya yako mwenyewe.

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Kimsingi, kwa kila barua na kila idadi na kila tabia

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kuna idadi kuhusishwa na wao,

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na hivyo ni vizuri kuona maadili yao ASCII sambamba barua halisi.

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Hiyo dhahiri kukusaidia katika kuweka tatizo.

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Jambo moja kwamba kweli imenisaidia katika kuweka tatizo hili lilikuwa kweli magazeti ni nje,

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na kama mimi alikuwa anaenda kwa njia ya, mimi ingekuwa kweli kuteka juu yake,

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kuandika, "Kama hii ina kwenda huko, basi ..."

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Aina ya kuteka juu yake na alama yake juu, kuwa bora na marafiki pamoja na meza yako ASCII.

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Basi tuna chache zana nyingine tulizonazo.

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Hii wakati badala ya kweli uvuvio mtumiaji kwa ajili ya wote ya pembejeo zao

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tunakwenda kufanya mchanganyiko.

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Sisi ni kwenda kuwashawishi kwa ajili ya pembejeo baadhi,

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lakini sisi ni pia kwenda tu kutumia hoja mstari amri.

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Basi walipo kuendesha programu zao, kwa kawaida unaweza kusema /. Hello, kwa mfano,

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kama mpango wako ulikuwa hello.c.

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Lakini wakati huu badala ya kusema tu kwamba, wanaweza kuweka maneno hoja, baadaye.

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Na hivyo sisi ni kwenda kutumia chochote kupita katika kwetu kama mchango wao pia,

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hivyo kusonga zaidi tu uvuvio kwa integer lakini pia kutumia hoja mstari amri.

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Na kisha tutaweza kwenda katika arrays na masharti, ambayo sisi utakuwa kutumia mengi pia.

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Hapa ni mfano tu ya chati 1 mini ASCII.

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Kama nilivyosema, kila barua sambamba na idadi,

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na hivyo jizoeshe na kwamba. Ni atakuja katika Handy.

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Na baadaye wakati sisi kuanza kufanya baadhi ASCIIMath kushughulika na idadi -

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akiongeza, subtracting yao - basi dhahiri nzuri kwa kutaja chati hii.

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Hivyo hapa ni mfano wa cipher Caesar - kitu ambacho unaweza kuwa alicheza na.

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Ni haki ya gurudumu. Kimsingi, kuna alfabeti nje na kisha kuna alfabeti ndani.

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Hivyo haki hapa ni mfano wa cipher Kaisari lakini kwa ufunguo wa 0.

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Kimsingi, ni iliyokaa na, B ni iliyokaa na B, njia yote hadi Z.

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Lakini kisha kusema tulitaka muhimu ya 3, kwa mfano.

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Basi tutakuwa mzunguko gurudumu ya ndani ili sasa aligns na D, nk

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Na hivyo hii kimsingi ni nini tunakwenda kufanya.

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Hatuna gurudumu, lakini nini tunakwenda kufanya ni kufanya mpango wetu

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aina ya kuhama alfabeti pamoja na sisi kiasi fulani ya namba.

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Hivyo kama nilivyosema hapo kabla, tunakwenda kuwa kushughulika na hoja mstari amri

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kama vile kupata integer.

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Hivyo njia kwamba mtumiaji kukimbia yako Kaisari mpango ni kwa kusema. / Kaisari

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na kisha kuingia idadi baada ya hapo.

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Na kwamba idadi hiyo inawakilisha muhimu, kuhama,

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mara ngapi wewe utaenda kupokezana gurudumu ndani ya cipher yako Kaisari.

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Na hivyo unaweza kuona hapa mfano.

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Kama sisi aliingia barua kutoka kwa L katika cipher wetu Kaisari,

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basi ingekuwa pembejeo D kupitia O kwa sababu hiyo ni kila barua kubadilishwa zaidi ya mara 3,

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tu kama mfano wa gurudumu ambayo nilikuonyeshea.

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Hivyo basi kama wewe aliingia, kwa mfano, Hii ​​ni CS50!

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basi ingekuwa pia hoja yote ya barua.

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Na kwamba ni jambo muhimu katika wawili Kaisari na Vigenere

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ni kwamba sisi ni kwenda ruka juu ya barua zisizo yoyote.

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Hivyo yoyote nafasi, herufi, nk, idadi, tunakwenda kuwaweka sawa.

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Sisi ni kwenda tu kuhama barua katika kesi hii.

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Hivyo kama unaweza kuona katika gurudumu, sisi tu barua inapatikana kwetu,

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hivyo sisi tu wanataka kuhama barua na kusimba barua.

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Hivyo jambo la kwanza kufanya, ninyi kuona kwamba matumizi kwa Kaisari katika tatizo kuweka 2

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ni kukimbia Kaisari na kisha kuingia idadi wakati wewe kukimbia katika terminal.

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Basi nini tunahitaji kufanya ni namna fulani kupata kwamba muhimu na kupata hiyo.

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Na hivyo tunataka kuona namna fulani ni kwenda kuwa ya pili ya mstari amri hoja.

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moja ya kwanza ni kwenda kuwa. / Kaisari, na moja ijayo itakuwa ni idadi muhimu.

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Hivyo kabla tulikuwa int kuu (utupu) kuanza C programu yetu.

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Sisi ni kwenda safu peel nyuma kidogo

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na kweli kuona kwamba badala ya kupita katika utupu kwa kazi yetu kuu

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sisi ni kweli kushughulika na vigezo 2.

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Tuna int aitwaye argc na kisha safu ya masharti kuitwa argv.

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Hivyo argc ni integer,

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na inawakilisha idadi ya hoja kupita katika mpango wako.

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Na kisha argv ni kweli orodha ya hoja kupita.

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Yote ya hoja ni masharti, na hivyo argv inawakilisha safu, orodha, ya masharti.

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Hebu majadiliano kuhusu arrays kidogo.

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Arrays ni kimsingi mpya data muundo.

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Tuna ints, tuna mara mbili, tuna masharti, na sasa tuna arrays.

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Arrays ni data miundo ambayo inaweza kushikilia maadili mbalimbali ya aina moja,

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hivyo kimsingi, orodha ya kila aina unataka.

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Kimsingi, kama alitaka orodha ya integers wote katika variable 1,

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basi ingekuwa kujenga variable mpya ambayo ilikuwa ya aina safu int.

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Hivyo arrays ni sifuri-indexed, kwa maana kwamba kipengele kwanza ya safu ni katika index 0.

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Kama safu ni ya urefu 4, kama katika mfano huu, basi kipengele yako ya mwisho itakuwa katika index 3,

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ambayo ni 4-1.

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Hivyo kujenga safu, ungependa kufanya kitu kama hiki.

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Sema wewe alitaka safu mbili.

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Hii inakwenda kwa aina yoyote ya aina data, ingawa.

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Hivyo kusema unataka safu mbili. Sema unataka simu yake mailbox.

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Just kama ungependa initialize yoyote mbili nyingine,

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wewe kusema mara mbili na kisha jina, lakini wakati huu sisi kuweka mabano mraba,

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na kisha namba kutakuwa urefu wa safu.

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Kumbuka kuwa katika arrays hatuwezi kubadilika urefu,

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hivyo daima kuwa kufafanua na kuchagua masanduku ngapi,

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wangapi maadili safu yako anaenda kushikilia.

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Hivyo kuweka maadili mbalimbali katika safu yako, utaenda kutumia syntax zifuatazo,

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kama unaweza kuona kwenye slide.

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Mailbox una 0 index itakuwa kuweka 1.2,

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mailbox index 1 kuweka 2.4, nk

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Hivyo sasa kwamba tumekuwa upya arrays kidogo, hebu kwenda nyuma argc na argv.

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Tunajua kwamba argv sasa ni safu ya masharti.

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Hivyo wakati mtumiaji hupita katika - kusema wanakimbia mpango -

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wanasema / hujambo Daudi Malan.,

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nini mpango kufanya kwa ajili yenu ni kweli tayari kuja na kile argc na argv ni.

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Hivyo huna haja ya kuwa na wasiwasi juu ya hilo.

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Argc katika kesi hii itakuwa 3 kwa sababu anaona 3 maneno tofauti waliojitenga na mazingira.

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Na hivyo basi safu katika mfano huu, ripoti ya kwanza itakuwa /. Hello,

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ijayo moja Daudi, ijayo moja Malan.

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Je, mtu yeyote kuona haki mbali uhusiano gani kati ya argv,

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 safu, na argc ni?

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Yeah. Tutaweza kupata ndani ya kwamba katika mfano katika args.c.

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Hebu tuone kama tunaweza kuchukua faida ya uhusiano kati ya 2.

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Hapa unaweza kupata kwamba katika appliance maombi default

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kufungua. files c ni wakati mwingine Emacs.

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Lakini tunataka kukabiliana na gedit, hivyo nini unaweza kufanya ni unaweza kulia bonyeza C faili yako,

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kwenda Properties, Fungua Kwa, na kisha kuchagua gedit, Kuweka kama default,

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na sasa mpango wako inapaswa kufungua katika gedit badala ya Emacs.

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Perfect.

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Hivyo hapa nina mpango kwamba nataka magazeti nje ya kila mstari amri hoja.

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Hivyo kila mtumiaji pembejeo, nataka kimsingi kurudi nyuma yao kwenye mstari mpya.

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Basi nini muundo kwamba tunaweza kutumia kwa iterate juu ya kitu fulani -

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kitu ambacho pengine kutumika katika 1 pset yako?

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Kama unataka kwenda kwa idadi ya seti ya vitu? >> [Mwanafunzi] Kwa kitanzi.

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Kwa kitanzi. Hasa. Basi hebu kuanza na kwa kitanzi.

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Tuna kwa int i = 0. Hebu tu kuanza na kutofautiana kiwango initialization.

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Mimi naenda kuondoka hali kwa ajili ya kuweka na kisha kusema i + +, kwenda kufanya mambo huko.

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Wote haki.

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Hivyo kufikiri nyuma argv, ikiwa ni argv orodha ya hoja kupita katika mpango

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na argc ni idadi ya hoja katika mpango,

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basi hiyo ina maana kwamba argc kimsingi ni urefu wa argv, kulia,

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kwa sababu kuna ni kwenda kuwa kama hoja nyingi kama thamani ya argc.

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Hivyo kama tunataka iterate juu ya kila kipengele katika argv,

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tunakwenda wanataka kila wakati kupata variable katika argv katika index aliyopewa.

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Ambayo yanaweza kuwakilishwa na hii, sawa?

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Hii variable hapa inawakilisha string hasa katika mfano huu

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sababu ni safu string - string hasa katika index kwamba aliyopewa.

180
00:12:57,030 --> 00:13:00,690
Nini tunataka kufanya, katika kesi hii tunataka magazeti yake nje, hivyo hebu sema printf.

181
00:13:00,690 --> 00:13:04,680
Na sasa argv ni kamba, hivyo tunataka kuweka kwamba placeholder huko.

182
00:13:04,680 --> 00:13:08,430
Tunataka mstari mpya tu kufanya ni kuangalia nzuri.

183
00:13:08,430 --> 00:13:12,530
Hivyo hapa tuna kitanzi kwa. Hatuna hali bado.

184
00:13:12,530 --> 00:13:20,020
Hivyo i kuanza saa 0, na kisha kila wakati ni kwenda magazeti string aliyopewa

185
00:13:20,020 --> 00:13:22,980
saa kwamba index hasa katika safu.

186
00:13:22,980 --> 00:13:28,410
Hivyo wakati wa kufanya sisi unataka kuacha kuchapa nje vipengele katika safu?

187
00:13:28,410 --> 00:13:35,720
Wakati tumekuwa kumaliza, haki? Wakati sisi Umefikia mwisho wa safu.

188
00:13:35,720 --> 00:13:38,870
Hivyo hatutaki kisichozidi uliopita urefu wa safu,

189
00:13:38,870 --> 00:13:43,700
na sisi tayari kujua sisi hawana haja ya kweli kikamilifu kujua nini urefu wa argv ni

190
00:13:43,700 --> 00:13:47,520
sababu ni tuliyopewa na nini hiyo? Argc. Hasa.

191
00:13:47,520 --> 00:13:56,640
Hivyo tunataka kufanya hili argc mchakato idadi ya nyakati.

192
00:13:56,640 --> 00:13:59,550
Mimi si katika saraka ya haki.

193
00:14:02,100 --> 00:14:03,490
Wote haki.

194
00:14:03,490 --> 00:14:08,990
Sasa wacha kufanya args. Hakuna makosa, ambayo ni kubwa.

195
00:14:08,990 --> 00:14:11,430
Basi hebu kukimbia tu args.

196
00:14:11,430 --> 00:14:15,130
Nini hii kwenda na kurudi kwetu? Ni tu kwenda na magazeti hayo tena.

197
00:14:15,130 --> 00:14:18,320
"Wewe inputted args katika mpango; Mimi naenda kuwapa nyuma yenu."

198
00:14:18,320 --> 00:14:23,170
Basi hebu kusema tunataka kusema args kisha foo bar.

199
00:14:23,170 --> 00:14:26,570
Hivyo basi ni Prints ni nje nyuma yetu. Wote haki?

200
00:14:26,570 --> 00:14:30,790
Kwa hiyo, kuna mfano wa jinsi gani unaweza kutumia argc na argv

201
00:14:30,790 --> 00:14:33,460
tukijua kwamba argc inawakilisha urefu wa argv.

202
00:14:33,460 --> 00:14:42,750
Kuhakikisha kwamba huna milele na arrays upatikanaji moja zaidi ya urefu wa safu

203
00:14:42,750 --> 00:14:45,140
kwa sababu C dhahiri kelele saa wewe.

204
00:14:45,140 --> 00:14:47,560
Utapata kitu kinachoitwa kosa segmentation,

205
00:14:47,560 --> 00:14:52,470
ambayo ni kamwe fun, kimsingi akisema wewe ni kujaribu kupata kitu

206
00:14:52,470 --> 00:14:55,000
kwamba haipo, si mali yenu.

207
00:14:55,000 --> 00:14:59,430
Hivyo kuhakikisha, na hasa kwa Indexing sifuri-, sisi hatutaki -

208
00:14:59,430 --> 00:15:02,390
Kama kwa mfano, kama tuna safu ya urefu 4,

209
00:15:02,390 --> 00:15:07,240
kwamba index safu 4 haipo kwa sababu sisi kuanza saa 0, saa index sifuri.

210
00:15:07,240 --> 00:15:11,730
Itakuwa asili ya pili tu kama kwa matanzi wakati sisi kuanza saa 0.

211
00:15:11,730 --> 00:15:13,610
Hivyo tu kuendelea kuwa katika akili.

212
00:15:13,610 --> 00:15:22,590
Wewe hawataki milele kupata index ya safu hiyo ni nje ya uwezo wako.

213
00:15:26,710 --> 00:15:32,560
Hivyo tunaweza kuona jinsi sasa tunaweza aina ya upatikanaji

214
00:15:32,560 --> 00:15:35,930
mstari amri hoja kwamba ni kupita in

215
00:15:35,930 --> 00:15:41,330
Lakini kama wewe niliona kamba, argv ni kweli safu kamba.

216
00:15:41,330 --> 00:15:45,740
Hivyo ni kweli si integer bado, lakini katika Kaisari tunataka kukabiliana na integers.

217
00:15:45,740 --> 00:15:54,430
Kwa bahati, kuna kazi umba kwa ajili yetu kwamba kweli anaweza kubadilisha kamba integer.

218
00:15:54,430 --> 00:15:58,710
Pia katika hapa sisi si kushughulika na pembejeo mtumiaji ambapo sisi ni uvuvio yao

219
00:15:58,710 --> 00:16:03,740
kwa ajili ya pembejeo hapa kwa ajili ya muhimu, hivyo hatuwezi kweli reprompt na kusema,

220
00:16:03,740 --> 00:16:07,840
"Oh, nipe mwingine integer, kusema, kama si halali."

221
00:16:07,840 --> 00:16:10,540
Lakini sisi bado kufanya haja ya kuangalia kwa ajili ya matumizi sahihi.

222
00:16:10,540 --> 00:16:13,520
Katika Kaisari wao ni kuruhusiwa tu kwa kupita katika namba 1,

223
00:16:13,520 --> 00:16:18,030
na hivyo kuwa na kukimbia. / Kaisari na kisha wao kuwa na kukupa idadi.

224
00:16:18,030 --> 00:16:23,660
Hivyo argc ina kuwa idadi fulani.

225
00:16:23,660 --> 00:16:29,060
Nini idadi ingekuwa kwamba kuwa kama wana kupita wewe /. Kaisari na kisha muhimu?

226
00:16:29,060 --> 00:16:32,920
Nini ni argc? >> [Mwanafunzi] 2. >> Mbili. Hasa.

227
00:16:32,920 --> 00:16:35,490
Hivyo unataka kuhakikisha kwamba argc ni 2.

228
00:16:35,490 --> 00:16:39,620
Vinginevyo wewe kimsingi kukataa kuendesha programu.

229
00:16:39,620 --> 00:16:43,040
Katika kuu ni kazi ambayo anasema int kuu,

230
00:16:43,040 --> 00:16:47,360
hivyo basi sisi daima katika mema 0 mazoezi kurudi katika mwisho wa mpango mafanikio.

231
00:16:47,360 --> 00:16:50,840
Hivyo kama, kusema, wao kukupa 3 hoja mstari amri badala ya 2

232
00:16:50,840 --> 00:16:54,350
au kukupa 1, kwa mfano, basi nini wewe itabidi kufanya ni utasikia wanataka kuangalia kwa kuwa

233
00:16:54,350 --> 00:16:59,900
na kisha kurudi 1 akisema, hapana, siwezi kuendelea na mpango huu.

234
00:16:59,900 --> 00:17:03,190
[Mwanafunzi] Kuna hawezi kuwa nafasi katika maandishi yako. >> Kunradhi?

235
00:17:03,190 --> 00:17:06,780
[Mwanafunzi] Kuna hawezi kuwa nafasi katika maandishi wewe ni kujaribu kuficha.

236
00:17:06,780 --> 00:17:08,480
Ah!

237
00:17:08,480 --> 00:17:11,280
Katika suala la Nakala kwamba sisi ni kujaribu kuficha, kwamba kwa kweli inakuja baadaye

238
00:17:11,280 --> 00:17:13,970
tunapotoa kwamba maandishi.

239
00:17:13,970 --> 00:17:18,260
Hivyo sasa hivi sisi ni tu kukubali kama hoja amri idadi halisi,

240
00:17:18,260 --> 00:17:21,579
kuhama halisi kwa encryption Kaisari.

241
00:17:21,579 --> 00:17:27,569
[Mwanafunzi] Kwa nini unahitaji 2 kinyume na tu argc 1? Kuna dhahiri 1 idadi.

242
00:17:27,569 --> 00:17:32,200
Haki. Sababu kwa nini tunahitaji 2 kwa argc badala ya 1

243
00:17:32,200 --> 00:17:36,260
ni kwa sababu wakati wewe kukimbia na mpango na kusema. / Kaisari, au /. hello,

244
00:17:36,260 --> 00:17:38,280
kwamba kweli makosa kama hoja mstari amri.

245
00:17:38,280 --> 00:17:43,020
Hivyo basi, kwamba tayari inachukua hadi 1 na hivyo basi tuko inputting 1 ziada.

246
00:17:45,030 --> 00:17:49,440
Basi, wewe ni kweli inputting string katika hoja mstari amri.

247
00:17:49,440 --> 00:17:52,730
Nini unataka kufanya, kwa Kaisari tunataka kukabiliana na integer,

248
00:17:52,730 --> 00:17:57,180
hivyo unaweza kutumia kazi hii atoi.

249
00:17:57,180 --> 00:18:02,850
Na kimsingi, wewe kupita katika kamba na kisha atarudi nyuma yenu integer

250
00:18:02,850 --> 00:18:06,070
kama inawezekana kufanya ile kamba ndani ya integer.

251
00:18:06,070 --> 00:18:10,960
Sasa kumbuka wakati sisi ni kushughulika na mambo printf au GetString, kama kwamba,

252
00:18:10,960 --> 00:18:13,390
sisi ni pamoja na maktaba kwamba ni maalum kwa sisi.

253
00:18:13,390 --> 00:18:19,450
Hivyo mwanzoni sisi kuanza na hash tag kitu standard I / O, h., Kama hiyo.

254
00:18:19,450 --> 00:18:22,430
Naam, atoi si ndani ya moja ya maktaba hizo,

255
00:18:22,430 --> 00:18:26,600
hivyo kile sisi kufanya ni sisi ni pamoja na maktaba ya haki kwa ajili hiyo.

256
00:18:26,600 --> 00:18:32,720
Hivyo kukumbuka nyuma walkthrough 1 ambapo mimi kujadiliwa kazi mwongozo.

257
00:18:32,720 --> 00:18:37,110
Unapoandika mtu katika terminal yako na kisha kufuatiwa na jina la kazi.

258
00:18:37,110 --> 00:18:39,720
Na ili kuleta orodha nzima ya matumizi yake,

259
00:18:39,720 --> 00:18:42,890
lakini pia itakuwa kuleta juu ambayo maktaba ambayo ni mali ya.

260
00:18:42,890 --> 00:18:47,000
Hivyo mimi itabidi kuondoka kwamba kwa wewe kutumia kazi mwongozo na atoi

261
00:18:47,000 --> 00:18:53,360
na kufikiri ambayo maktaba unahitaji ni pamoja na kuwa na uwezo wa kutumia kazi atoi.

262
00:18:54,450 --> 00:18:57,670
Hivyo sisi tumepewa muhimu na sasa ni suala la kupata Nakala wazi,

263
00:18:57,670 --> 00:19:01,820
na hivyo kwamba kweli ni kwenda kuwa mtumiaji pembejeo ambapo wewe kuchochea.

264
00:19:01,820 --> 00:19:05,540
Sisi kushughulikiwa na GetInt na GetFloat, na hivyo katika ven

265
00:19:05,540 --> 00:19:07,670
tunakwenda kuwa kushughulika na GetString.

266
00:19:07,670 --> 00:19:12,440
Lakini katika kesi hii hatuna haja ya kufanya lolote do wakati au wakati matanzi ya kuangalia.

267
00:19:12,440 --> 00:19:14,480
GetString dhahiri kutupa kamba,

268
00:19:14,480 --> 00:19:17,630
na sisi ni kwenda encrypt chochote mtumiaji inatupa.

269
00:19:17,630 --> 00:19:23,770
Hivyo unaweza kudhani kuwa yote haya masharti ya mtumiaji inputted ni sahihi.

270
00:19:23,770 --> 00:19:24,670
Mkuu.

271
00:19:24,670 --> 00:19:27,270
Hivyo basi mara moja nimepata muhimu na mara moja nimepata maandishi,

272
00:19:27,270 --> 00:19:31,660
sasa nini kushoto ni una encipher maandishi wazi.

273
00:19:31,660 --> 00:19:36,530
Tu kwa haraka ufunike Hands, maandishi wazi ni nini mtumiaji inakupa,

274
00:19:36,530 --> 00:19:41,030
na nakala ya siri ni nini kurudi kwao.

275
00:19:42,450 --> 00:19:45,850
Hivyo masharti, kuwa na uwezo wa kwenda kwa njia ya barua kweli kwa barua

276
00:19:45,850 --> 00:19:48,550
sababu tuna kuhama kila herufi,

277
00:19:48,550 --> 00:19:51,390
sisi kuelewa masharti kwamba, kama sisi aina ya Peel nyuma safu,

278
00:19:51,390 --> 00:19:54,130
tunaona kwamba wao ni kweli tu orodha ya wahusika.

279
00:19:54,130 --> 00:19:55,930
Moja anakuja baada ya nyingine.

280
00:19:55,930 --> 00:20:01,690
Na hivyo tunaweza kutibu masharti kama arrays kwa sababu wao ni arrays ya wahusika.

281
00:20:01,690 --> 00:20:05,640
Hivyo kusema kuwa string aitwaye maandishi,

282
00:20:05,640 --> 00:20:09,400
na ndani ya maandishi kwamba variable ni kuhifadhiwa Hii ni CS50.

283
00:20:09,400 --> 00:20:15,680
Kisha Nakala saa index 0 itakuwa Simu mji mkuu, index 1 itakuwa h, nk

284
00:20:17,530 --> 00:20:23,970
Na kisha na arrays, katika mfano argc katika args.c,

285
00:20:23,970 --> 00:20:27,090
tuliona kwamba tulikuwa na iterate juu ya safu

286
00:20:27,090 --> 00:20:32,440
na hivyo alikuwa na iterate kutoka i = 0 hadi i ni chini ya urefu.

287
00:20:32,440 --> 00:20:35,560
Hivyo tunahitaji baadhi ya njia ya kuhesabia nje nini urefu wa kamba yetu ni

288
00:20:35,560 --> 00:20:37,090
kama sisi ni kwenda iterate juu yake.

289
00:20:37,090 --> 00:20:42,300
Kwa bahati tena, kuna kazi huko kwa ajili yetu, ingawa baadaye katika CS50

290
00:20:42,300 --> 00:20:45,860
wewe utakuwa dhahiri kuwa na uwezo wa kutekeleza na kufanya kazi yako mwenyewe

291
00:20:45,860 --> 00:20:48,260
ambayo inaweza mahesabu ya urefu wa kamba.

292
00:20:48,260 --> 00:20:52,120
Lakini kwa sasa tunakwenda kutumia kamba urefu, hivyo strlen.

293
00:20:52,120 --> 00:21:00,440
Wewe kupita katika kamba, na kisha atarudi wewe int kwamba inawakilisha urefu wa kamba yako.

294
00:21:00,440 --> 00:21:05,840
Hebu tuangalie mfano wa jinsi sisi kuwa na uwezo wa iterate juu ya kila tabia katika string

295
00:21:05,840 --> 00:21:08,470
na kufanya kitu na kwamba.

296
00:21:08,470 --> 00:21:13,250
Nini tunataka kufanya ni iterate juu ya kila tabia ya kamba,

297
00:21:13,250 --> 00:21:19,150
na nini tunataka kufanya ni sisi magazeti nyuma kila tabia 1 na 1

298
00:21:19,150 --> 00:21:22,060
ila sisi kuongeza kitu karibu na hiyo.

299
00:21:22,060 --> 00:21:27,020
Basi hebu kuanza na kwa kitanzi. Int i = 0.

300
00:21:27,020 --> 00:21:30,070
Sisi ni kwenda kuacha nafasi kwa ajili ya hali hiyo.

301
00:21:32,700 --> 00:21:36,840
Tunataka iterate mpaka sisi kufikia mwisho wa kamba, sawa?

302
00:21:36,840 --> 00:21:41,340
Hivyo basi nini kazi inatupa urefu wa kamba?

303
00:21:41,340 --> 00:21:43,160
[Inaudible mwanafunzi majibu]

304
00:21:43,160 --> 00:21:46,420
Hiyo ni urefu wa hoja mstari amri.

305
00:21:46,420 --> 00:21:50,650
Lakini kwa kamba tunataka kutumia kazi ambayo inatupa urefu wa kamba.

306
00:21:50,650 --> 00:21:53,090
Basi hiyo ni kamba urefu.

307
00:21:53,090 --> 00:21:57,130
Na hivyo basi una kupita katika kamba hiyo.

308
00:21:57,130 --> 00:21:59,760
Ni mahitaji ya kujua nini string inahitaji mahesabu ya urefu wa.

309
00:21:59,760 --> 00:22:03,160
Hivyo basi katika kesi hii sisi ni kushughulika na uzi s.

310
00:22:04,790 --> 00:22:05,860
Mkuu.

311
00:22:05,860 --> 00:22:10,770
Hivyo basi nini tunataka kufanya, hebu printf.

312
00:22:10,770 --> 00:22:14,850
Sasa, tunataka kukabiliana na wahusika. Tunataka magazeti nje kila tabia ya mtu binafsi.

313
00:22:14,850 --> 00:22:22,150
Wakati unataka kwa magazeti nje kuelea, ungependa kutumia placeholder kama f%.

314
00:22:22,150 --> 00:22:24,580
Pamoja na int ungependa kutumia% d.

315
00:22:24,580 --> 00:22:30,890
Na hivyo vile vile, na tabia wewe kutumia c% kusema mimi nina kwenda kuwa uchapishaji tabia

316
00:22:30,890 --> 00:22:34,570
ambayo imehifadhiwa ndani ya kutofautiana.

317
00:22:34,570 --> 00:22:40,840
Hivyo tuna hii, na hebu kuongeza kipindi na nafasi yake.

318
00:22:40,840 --> 00:22:45,430
Ambayo ni tabia ya sisi kutumia?

319
00:22:45,430 --> 00:22:49,780
Sisi wanaenda kutumia chochote kile tabia sisi ni saa ya kamba.

320
00:22:49,780 --> 00:22:52,890
Hivyo basi sisi wanaenda kutumia kitu kwa kamba,

321
00:22:52,890 --> 00:22:56,420
lakini tunataka kuwa kupata huduma ya tabia fulani huko.

322
00:22:56,420 --> 00:23:02,740
Hivyo kama ni kamba tu safu, basi, jinsi gani sisi kupata mambo ya arrays?

323
00:23:02,740 --> 00:23:06,480
Tuna mabano mraba those, na kisha sisi kuweka index huko.

324
00:23:06,480 --> 00:23:11,820
Hivyo tuna mabano mraba. Index yetu katika kesi hii tunaweza kutumia tu i. Hasa.

325
00:23:15,290 --> 00:23:22,370
Hivyo hapa sisi ni kusema sisi ni kwenda kuwa uchapishaji tabia kufuatiwa na dot na nafasi,

326
00:23:22,370 --> 00:23:30,870
na tabia ya kuwa ni kwenda kuwa barua idh katika kamba s yetu.

327
00:23:32,920 --> 00:23:39,330
Mimi tu anaenda kuokoa. Sawa.

328
00:23:42,510 --> 00:23:46,840
Sasa mimi nina kwenda kukimbia string urefu.

329
00:23:46,840 --> 00:23:53,440
Hivyo tulikuwa string kuitwa OMG, na sasa ni alisisitiza hata zaidi.

330
00:23:53,440 --> 00:23:57,870
Vile vile, hebu sema sisi kweli wanataka kupata kamba kutoka kwa mtumiaji.

331
00:23:57,870 --> 00:23:59,580
Jinsi gani tunafanya hivi?

332
00:23:59,580 --> 00:24:01,610
Kabla ya hapo, jinsi gani sisi kupata int?

333
00:24:01,610 --> 00:24:08,040
Sisi alisema GetInt, haki? Lakini hii si int, hivyo hebu GetString.

334
00:24:11,780 --> 00:24:17,770
Hebu kufanya string urefu. Hapa sisi hawakuwa kuingia haraka maalum.

335
00:24:17,770 --> 00:24:19,940
Hivyo mimi sijui.

336
00:24:19,940 --> 00:24:23,820
Mimi naenda kuweka jina langu katika hapa na hivyo basi naweza kufanya moja ya mambo

337
00:24:23,820 --> 00:24:29,600
ambapo mimi hawawajui neno kwa kila barua au kitu kama hicho. Cool.

338
00:24:29,600 --> 00:24:31,900
Basi hiyo ni kamba urefu.

339
00:24:33,000 --> 00:24:34,640
Hivyo sisi ni nyuma ya Kaisari.

340
00:24:34,640 --> 00:24:38,620
Tuna zana chache juu ya jinsi sisi iterate juu ya kamba,

341
00:24:38,620 --> 00:24:41,250
jinsi sisi kupata kila kipengele binafsi.

342
00:24:41,250 --> 00:24:44,720
Hivyo sasa tunaweza kupata nyuma ya mpango.

343
00:24:44,720 --> 00:24:48,650
Kama nilivyoeleza hapo awali, katika meza ASCII, rafiki yako,

344
00:24:48,650 --> 00:24:52,300
utaenda kuona idadi kuwa ni kuhusishwa na kila barua.

345
00:24:52,300 --> 00:24:55,900
Hivyo hapa kusema maandishi wazi yetu ni mimi nina kizunguzungu!

346
00:24:55,900 --> 00:25:01,090
Ndipo kila mmoja wa wahusika hawa ni kwenda kuwa na idadi na thamani ASCII yanayohusiana na hayo,

347
00:25:01,090 --> 00:25:04,710
hata apostrophe, hata nafasi, hata alama Moderators,

348
00:25:04,710 --> 00:25:06,600
hivyo utasikia wanataka kuendelea kuwa katika akili.

349
00:25:06,600 --> 00:25:12,360
Hivyo kusema ufunguo yetu kwamba mtumiaji pamoja na katika hoja zao amri line ni 6.

350
00:25:12,360 --> 00:25:17,770
Hiyo ina maana kwa barua ya kwanza, ambayo ni mimi, ambayo ni kuwakilishwa na 73,

351
00:25:17,770 --> 00:25:25,610
unataka kurudi kwao chochote barua ni kuwakilishwa na thamani ya 73 + ASCII 6.

352
00:25:25,610 --> 00:25:29,020
Katika kesi hiyo ambayo itakuwa ya 79.

353
00:25:30,840 --> 00:25:35,040
Sasa tunataka kwenda kwa tabia ijayo.

354
00:25:35,040 --> 00:25:40,960
Hivyo ijayo katika index 1 ya maandishi wazi itakuwa apostrophe.

355
00:25:40,960 --> 00:25:46,780
Lakini kumbuka sisi tu wanataka encipher barua.

356
00:25:46,780 --> 00:25:50,040
Hivyo tunataka kuhakikisha kwamba apostrophe kweli anakaa huo,

357
00:25:50,040 --> 00:25:54,310
kwamba hatuwezi kubadilika kutoka 39 hadi 45 ni chochote.

358
00:25:54,310 --> 00:25:57,150
Tunataka kuitunza kama apostrophe.

359
00:25:57,150 --> 00:26:00,780
Hivyo tunataka kumbuka tu encipher barua

360
00:26:00,780 --> 00:26:04,560
sababu tunataka wote wa ishara nyingine kubaki unchanged katika programu yetu.

361
00:26:04,560 --> 00:26:07,130
Jambo jingine ni kwamba tunataka ni kulinda mtaji.

362
00:26:07,130 --> 00:26:10,250
Hivyo wakati una barua uppercase, ni lazima kukaa kama uppercase.

363
00:26:10,250 --> 00:26:12,830
Lowercases wanapaswa kukaa kama lowercase.

364
00:26:13,620 --> 00:26:19,480
Hivyo baadhi ya kazi muhimu kuwa na uwezo wa kukabiliana na barua tu enciphering

365
00:26:19,480 --> 00:26:22,380
na kuweka kuhifadhi mtaji wa mambo

366
00:26:22,380 --> 00:26:25,130
ni islower isalpha, isupper, kazi.

367
00:26:25,130 --> 00:26:29,270
Na hivyo haya ni kazi ya kwamba kurudi wewe thamani Boolean.

368
00:26:29,270 --> 00:26:34,180
Kimsingi, kweli au uongo. Je, hii ni uppercase? Je, hii ni alphanumeric?

369
00:26:34,180 --> 00:26:37,180
Je, hii ni barua, kimsingi.

370
00:26:37,180 --> 00:26:41,070
Hivyo hapa ni mifano 3 ya jinsi gani kutumia kazi.

371
00:26:41,070 --> 00:26:47,060
Kimsingi, unaweza mtihani kama thamani akarudi na wewe na kazi ambayo ni ya kweli au ya uongo

372
00:26:47,060 --> 00:26:49,400
msingi pembejeo kwamba.

373
00:26:49,400 --> 00:26:54,880
Aidha si encipher kitu au cipher au kuhakikisha kwamba ni uppercase, nk

374
00:26:54,880 --> 00:27:01,080
[Mwanafunzi] Je, unaweza kueleza tu wale kidogo zaidi na jinsi ya matumizi yao? >> Yeah, kwa uhakika.

375
00:27:01,080 --> 00:27:08,470
Hivyo kama sisi kuangalia nyuma, hapa tuna mtaji mimi, sawa?

376
00:27:08,470 --> 00:27:14,550
Hivyo tunajua kwamba mimi huenda kwa sababu mimi Enyi + 6 ni O.

377
00:27:14,550 --> 00:27:18,740
Lakini tunataka kuhakikisha kwamba O ni kwenda kuwa mji mkuu O.

378
00:27:18,740 --> 00:27:22,940
Hivyo kimsingi, kwamba ni aina ya kwenda na mabadiliko ya pembejeo yetu.

379
00:27:22,940 --> 00:27:26,870
Hivyo kama ni uppercase au si mapenzi ya aina ya kubadilisha njia ya kwamba sisi kukabiliana nayo.

380
00:27:26,870 --> 00:27:32,360
Hivyo basi kama sisi kutumia kazi isupper katika ripoti husika,

381
00:27:32,360 --> 00:27:36,480
hivyo isupper ("mimi"), kwamba anarudi kwa ajili yetu kweli, hivyo tunajua kwamba ni juu.

382
00:27:36,480 --> 00:27:40,360
Hivyo basi kwa kuzingatia kwamba, baadaye tutaweza kwenda katika formula

383
00:27:40,360 --> 00:27:42,750
kwamba wewe utakuwa kutumia kuhama mambo katika Kaisari,

384
00:27:42,750 --> 00:27:46,560
hivyo basi kimsingi, kuna kwenda kuwa formula tofauti kidogo kama ni uppercase

385
00:27:46,560 --> 00:27:50,670
kinyume na Herufi za chini. Mantiki?

386
00:27:51,020 --> 00:27:52,760
Yeah. Hakuna wasiwasi.

387
00:27:54,900 --> 00:27:58,990
Mimi kuongea kidogo kuhusu kuongeza 6 kwa barua, ambayo haina kabisa mantiki

388
00:27:58,990 --> 00:28:05,500
ila wakati sisi aina ya kuelewa kuwa hawa wahusika

389
00:28:05,500 --> 00:28:08,920
ni aina ya interchangeable na integers.

390
00:28:08,920 --> 00:28:11,250
Tunachofanya ni sisi aina ya akitoa matumizi thabiti.

391
00:28:11,250 --> 00:28:18,100
Tutaweza kwenda katika akitoa kidogo baadaye ambapo wewe kuchukua thamani na wewe kugeuka ndani ya aina mbalimbali

392
00:28:18,100 --> 00:28:20,440
kuliko awali alikuwa.

393
00:28:20,440 --> 00:28:25,910
Lakini pamoja na pset hii tutaweza kuwa na uwezo wa aina ya kubadilishana kutumia herufi

394
00:28:25,910 --> 00:28:30,880
na wao sambamba integer maadili.

395
00:28:30,880 --> 00:28:35,140
Hivyo kama wewe tu encase tabia na tu enda quotes,

396
00:28:35,140 --> 00:28:40,390
basi utakuwa na uwezo wa kufanya kazi na kwa integers, kukabiliana na ni kama integer.

397
00:28:40,390 --> 00:28:48,040
Hivyo C mtaji inahusiana na 67. F lowercase inahusiana na 102.

398
00:28:48,040 --> 00:28:51,480
Tena, kama unataka kujua maadili haya, kuangalia meza yako ASCII.

399
00:28:51,480 --> 00:28:56,160
Basi hebu kwenda katika baadhi ya mifano ya jinsi ya unavyoweza kuwa na uwezo wa Ondoa na kuongeza,

400
00:28:56,160 --> 00:29:03,130
jinsi unaweza kweli kweli kazi na wahusika hawa, matumizi yao kubadilishana.

401
00:29:03,870 --> 00:29:11,350
Nasema ASCIIMath kwamba ni kwenda kwa mahesabu ya nyongeza ya tabia kwa integer

402
00:29:11,350 --> 00:29:17,590
na kisha kuonyesha tabia matokeo kama vile matokeo ASCII thamani.

403
00:29:17,590 --> 00:29:22,290
Na hivyo hapa mimi kusema - we'll kukabiliana na sehemu hii baadaye -

404
00:29:22,290 --> 00:29:29,100
lakini kimsingi, mimi kusema kwamba mtumiaji lazima kusema kukimbia ASCIIMath pamoja na muhimu,

405
00:29:29,100 --> 00:29:30,880
na mimi kusema kwamba muhimu kwamba ni kwenda kuwa idadi

406
00:29:30,880 --> 00:29:34,600
ambayo sisi ni kwenda kuongeza tabia hii.

407
00:29:34,600 --> 00:29:38,560
Hivyo hapa taarifa kwamba tangu nina kudai muhimu,

408
00:29:38,560 --> 00:29:40,590
tangu mimi nina wanadai kwamba wao ni kunipa 1 kitu,

409
00:29:40,590 --> 00:29:45,600
Mimi nataka tu kukubali. / Asciimath na ufunguo.

410
00:29:45,600 --> 00:29:49,330
Hivyo nina kwenda kudai kwamba argc ni sawa na 2.

411
00:29:49,330 --> 00:29:54,360
Kama siyo, basi mimi naenda kurudi 1 na mpango exit.

412
00:29:55,070 --> 00:29:58,540
Hivyo mimi kusema muhimu si kwenda kuwa ya kwanza ya mstari amri hoja,

413
00:29:58,540 --> 00:30:05,080
itakavyo kuwa moja ya pili, na kama unaweza kuona hapa,

414
00:30:05,080 --> 00:30:11,790
Mimi naenda kugeuka kuwa ndani ya integer.

415
00:30:15,740 --> 00:30:19,230
Kisha Mimi naenda kuweka tabia kuwa r.

416
00:30:19,230 --> 00:30:23,970
Ona kwamba aina ya kutofautiana ni kweli CHR integer.

417
00:30:23,970 --> 00:30:30,480
njia ambayo nina uwezo wa kutumia r kama integer ni kwa encasing kwa hizi quotes moja.

418
00:30:33,850 --> 00:30:40,560
Hivyo nyuma kwa taarifa yetu printf ambapo tuna placeholder kwa tabia

419
00:30:40,560 --> 00:30:43,590
na kisha placeholder kwa integer,

420
00:30:43,590 --> 00:30:49,450
tabia ni kuwakilishwa na CHR, na integer ni muhimu.

421
00:30:49,450 --> 00:30:54,320
Na hivyo basi tunakwenda katika matokeo kuongeza 2 pamoja.

422
00:30:54,320 --> 00:30:58,420
Hivyo sisi ni kwenda kuongeza r + chochote muhimu ni,

423
00:30:58,420 --> 00:31:03,520
na kisha tunakwenda magazeti matokeo ya kwamba.

424
00:31:06,210 --> 00:31:14,220
Basi hebu kufanya asciimath. Ni juu ya tarehe, hivyo hebu kukimbia tu asciimath.

425
00:31:14,220 --> 00:31:18,290
Oh, lakini kuona, haina kufanya kitu chochote kwa sababu hatukuwa kweli kuwapa muhimu.

426
00:31:18,290 --> 00:31:23,850
Hivyo linapokuja tu akarudi 1, kazi yetu kuu, ni tu akarudi nyuma yetu.

427
00:31:23,850 --> 00:31:29,250
Hivyo basi hebu kupita katika muhimu. Mtu nipe namba. >> [Mwanafunzi] 4.

428
00:31:29,250 --> 00:31:30,920
4. Sawa.

429
00:31:30,920 --> 00:31:39,280
Hivyo r iliongezeka kwa 4 ni kwenda kutupa v, ambayo inalingana na thamani ASCII ya 118.

430
00:31:39,280 --> 00:31:43,880
Hivyo basi aina ya mantiki kwamba -

431
00:31:43,880 --> 00:31:51,250
Kweli, ninaweza kuuliza wewe, unafikiri nini thamani ASCII ya r ni kama r + 4 ni 118?

432
00:31:53,070 --> 00:31:55,470
Kisha yeah, r ni 114.

433
00:31:55,470 --> 00:32:03,010
Hivyo kama wewe kuangalia juu ya meza ASCII basi, uhakika wa kutosha, utaona r kwamba ni kuwakilishwa na 114.

434
00:32:03,010 --> 00:32:08,610
Hivyo sasa kwamba sisi kujua kwamba tunaweza kuongeza integers kwa wahusika, hii inaonekana pretty rahisi.

435
00:32:08,610 --> 00:32:12,740
Sisi ni kwenda tu iterate juu ya kamba kama tulivyoona katika mfano kabla.

436
00:32:12,740 --> 00:32:17,170
Tutaweza kuangalia kama ni barua.

437
00:32:17,170 --> 00:32:20,420
Kama ni, basi tutaweza kuhama hivyo kwa chochote muhimu ni.

438
00:32:20,420 --> 00:32:23,650
Pretty rahisi, isipokuwa wakati kupata kama hii,

439
00:32:23,650 --> 00:32:32,140
unaweza kuona kwamba z, kuwakilishwa na 122, basi bila kutoa tabia tofauti.

440
00:32:32,140 --> 00:32:37,770
Sisi kwa kweli wanataka kukaa ndani ya alfabeti yetu, haki?

441
00:32:37,770 --> 00:32:43,180
Hivyo tunahitaji kufikiri baadhi ya njia ya aina ya wrapping kote.

442
00:32:43,180 --> 00:32:47,190
Wakati kufikia Zed na unataka kuongeza kwa idadi fulani,

443
00:32:47,190 --> 00:32:51,230
hutaki kwenda ng'ambo ya sehemu ASCII alfabeti;

444
00:32:51,230 --> 00:32:54,140
unataka wrap nyuma njia yote ya A.

445
00:32:54,140 --> 00:32:58,550
Lakini kumbuka bado uko kuhifadhi kesi.

446
00:32:58,550 --> 00:33:00,980
Hivyo kwa kufahamu barua kwamba hawezi kuwa ishara

447
00:33:00,980 --> 00:33:05,290
tu kama ishara si kwenda kuwa kubadilisha pia.

448
00:33:05,290 --> 00:33:08,170
Katika pset mwisho wewe dhahiri hakuwa na haja ya,

449
00:33:08,170 --> 00:33:14,310
lakini chaguo lilikuwa kutekeleza pset yako tamaa na kutumia kazi modulus.

450
00:33:14,310 --> 00:33:17,230
Lakini sasa sisi ni kweli kwenda haja ya kutumia modulus,

451
00:33:17,230 --> 00:33:19,900
hivyo hebu tu kwenda juu kidogo hii ndogo.

452
00:33:19,900 --> 00:33:26,920
Kimsingi, wakati una x modulo y, kwamba anatoa salio ya x kugawanywa na y.

453
00:33:26,920 --> 00:33:30,930
Hapa ni baadhi ya mifano hapa. Tuna 27% 15.

454
00:33:30,930 --> 00:33:36,200
Kimsingi, wakati wewe Ondoa 15 kutoka 27 kwa mara nyingi kama inawezekana bila kupata hasi

455
00:33:36,200 --> 00:33:39,060
basi kupata 12 wa kushoto juu.

456
00:33:39,060 --> 00:33:44,650
Basi hiyo ni aina ya kama katika muktadha math, lakini ni jinsi gani tunaweza kweli matumizi ya hili?

457
00:33:44,650 --> 00:33:47,100
Ni kwenda kuwa na manufaa kwa wrapover yetu.

458
00:33:47,100 --> 00:33:55,420
Kwa hili, hebu sema tu mimi aliuliza wewe wote kujigawa katika vikundi 3.

459
00:33:55,420 --> 00:33:58,010
Wakati mwingine unaweza kufanya hili katika vikundi na kitu kama hicho.

460
00:33:58,010 --> 00:34:01,320
Sema mimi akasema, "Sawa, mimi nataka ninyi nyote kugawanywa katika 3."

461
00:34:01,320 --> 00:34:04,240
Jinsi gani unaweza kufanya hivyo?

462
00:34:04,240 --> 00:34:06,810
[Inaudible mwanafunzi majibu] Yeah, kwa uhakika. Hesabu mbali. Sawa.

463
00:34:06,810 --> 00:34:10,260
Hebu kweli kufanya hivyo. Je, unataka kuanza?

464
00:34:10,260 --> 00:34:13,810
[Wanafunzi kuhesabu off] 1, 2, 3, 4.

465
00:34:13,810 --> 00:34:16,620
Lakini kumbuka ... >> [Mwanafunzi] Oh, pole.

466
00:34:16,620 --> 00:34:18,730
Hiyo ni hatua nzuri kwa kweli.

467
00:34:18,730 --> 00:34:24,130
Wewe alisema 4, lakini sisi kweli nataka kusema 1 kwa sababu sisi tu kutaka makundi 3.

468
00:34:24,130 --> 00:34:30,159
Hivyo basi, jinsi - Hapana, hiyo ni mfano mzuri kwa sababu basi, jinsi utasema 1?

469
00:34:30,159 --> 00:34:33,370
Nini uhusiano kati ya 4 na 1?

470
00:34:33,370 --> 00:34:36,760
Naam, 4 Mod 3 ni 1.

471
00:34:36,760 --> 00:34:41,460
Hivyo kama wewe kuendelea, itakuwa 2.

472
00:34:41,460 --> 00:34:44,540
Hivyo tuna 1, 2, 3, 1, 2.

473
00:34:44,540 --> 00:34:49,420
Tena, wewe ni kweli mtu 5. Unajuaje kusema 2 badala ya 5?

474
00:34:49,420 --> 00:34:53,760
Unaweza kusema 5 Mod 3 ni 2.

475
00:34:53,760 --> 00:34:59,100
Nataka kuona jinsi makundi mengi ya 3 ni kushoto juu, kisha utaratibu upi ni I.

476
00:34:59,100 --> 00:35:02,860
Na hivyo basi kama sisi iliendelea pamoja chumba nzima,

477
00:35:02,860 --> 00:35:07,760
basi tunataka kuona kwamba sisi ni daima kwa kweli kutumia kazi Mod kwa wenyewe

478
00:35:07,760 --> 00:35:09,990
kwa aina ya kuhesabu mbali.

479
00:35:09,990 --> 00:35:14,490
Hiyo ni aina zaidi ya mfano yanayoonekana ya jinsi unaweza kutumia modulo

480
00:35:14,490 --> 00:35:17,960
kwa sababu mimi nina uhakika wengi wetu pengine wamekwenda kupitia mchakato wa kuwa

481
00:35:17,960 --> 00:35:19,630
ambapo tulikuwa na kuhesabu mbali.

482
00:35:19,630 --> 00:35:21,840
Maswali yoyote juu ya modulo?

483
00:35:21,840 --> 00:35:25,360
Itakuwa pretty muhimu kuelewa dhana hii,

484
00:35:25,360 --> 00:35:28,640
hivyo nataka kuhakikisha guys kuelewa.

485
00:35:28,640 --> 00:35:34,660
[Mwanafunzi] Kama kuna salio hakuna, je, ni kukupa idadi halisi?

486
00:35:34,660 --> 00:35:40,430
Kama moja ya kwanza 3 wao alikuwa amefanya hivyo, je, nimewapa kile kweli walikuwa,

487
00:35:40,430 --> 00:35:43,310
au ingekuwa ni nimewapa [inaudible] >> Hilo ni swali nzuri.

488
00:35:43,310 --> 00:35:48,750
Wakati hakuna salio kwa modulo - hivyo kusema kuwa 6 Mod 3 -

489
00:35:48,750 --> 00:35:52,340
kwamba kwa kweli anakupa nyuma 0.

490
00:35:53,670 --> 00:35:57,290
Tutazungumzia kwamba kidogo baadaye.

491
00:35:58,810 --> 00:36:07,720
Oh yeah, kwa mfano, mtu 3 - 3 Mod 3 ni kweli lakini alisema 0 3.

492
00:36:07,720 --> 00:36:14,900
Basi hiyo ni aina ya kama samaki wa ndani, kwa mfano,

493
00:36:14,900 --> 00:36:17,620
kama sawa, ikiwa ni Mod 0 basi mimi nitakuja kuwa mtu 3.

494
00:36:17,620 --> 00:36:22,740
Lakini tutaweza kupata katika aina ya jinsi sisi kutaka kukabiliana na kile 0 ni baadaye.

495
00:36:22,740 --> 00:36:32,750
Hivyo sasa sisi kwa namna fulani kuwa na njia ya ramani Zed kwa barua ya haki.

496
00:36:32,750 --> 00:36:34,920
Hivyo sasa tumeenda kwa njia ya mifano hii,

497
00:36:34,920 --> 00:36:37,880
sisi aina ya kuona jinsi Kaisari ili kazi.

498
00:36:37,880 --> 00:36:42,640
Unaweza kuona alphabets 2 na kisha kuwaona shifting.

499
00:36:42,640 --> 00:36:44,430
Basi hebu jaribu na kueleza kuwa katika suala la formula.

500
00:36:44,430 --> 00:36:46,940
Formula Hii ni kweli aliyopewa na wewe katika spec,

501
00:36:46,940 --> 00:36:52,070
lakini aina hebu ya kuangalia kwa nini kila variable maana yake.

502
00:36:52,070 --> 00:36:55,000
Mwisho wetu matokeo ni kwenda kuwa nakala ya siri.

503
00:36:55,000 --> 00:36:58,300
Hivyo hii anasema kwamba, tabia idh ya nakala ya siri

504
00:36:58,300 --> 00:37:02,500
ni kwenda yanahusiana na tabia idh ya maandishi wazi.

505
00:37:02,500 --> 00:37:08,130
Kwamba inafanya hisia kwa sababu tunataka daima bitana mambo haya juu.

506
00:37:08,130 --> 00:37:13,480
Hivyo ni kwenda kuwa tabia idh ya nakala ya siri plus k, ambayo ni muhimu yetu -

507
00:37:13,480 --> 00:37:17,230
kwamba inafanya hisia - na kisha tuna hii Mod 26.

508
00:37:17,230 --> 00:37:19,860
Kumbuka nyuma wakati tulikuwa na Zed

509
00:37:19,860 --> 00:37:24,190
sisi hakutaka kuingia katika tabia, hivyo sisi alitaka Mod ni

510
00:37:24,190 --> 00:37:26,540
na aina ya wrap kuzunguka alfabeti.

511
00:37:26,540 --> 00:37:33,430
Baada ya Zed ungependa kwenda, b, c, d, mpaka wewe got idadi ya haki.

512
00:37:33,430 --> 00:37:44,690
Hivyo tunajua kwamba Zed, ikiwa + 6, atatupa f kwa sababu baada ya Zed inakuja, b, c, d, e, f.

513
00:37:44,690 --> 00:37:52,530
Basi hebu kumbuka sisi kujua kwa uhakika kwamba zed + 6 ni kwenda kutupa f.

514
00:37:52,530 --> 00:38:03,530
Katika maadili ASCII, z ni 122 na f ni 102.

515
00:38:03,530 --> 00:38:10,570
Hivyo inabidi kutafuta baadhi ya njia ya maamuzi yetu Kaisari formula kutupatia 102

516
00:38:10,570 --> 00:38:13,590
baada ya kuchukua katika 122.

517
00:38:13,590 --> 00:38:19,550
Hivyo kama sisi tu kuomba hii formula,% ('z' + 6) 26, kwamba kwa kweli anakupa 24

518
00:38:19,550 --> 00:38:25,980
kwa sababu 122 + 6 ni 128; 128% 26 inakupa 24 salio.

519
00:38:25,980 --> 00:38:29,140
Lakini hiyo haina maana ya kweli f. Hiyo ni dhahiri si 102.

520
00:38:29,140 --> 00:38:33,590
Hiyo pia si barua 6 katika alfabeti.

521
00:38:33,590 --> 00:38:41,550
Hivyo ni wazi, tunahitaji kuwa na baadhi ya njia ya tweaking hii kidogo kidogo.

522
00:38:42,970 --> 00:38:51,340
Katika suala la alfabeti ya mara kwa mara, tunajua kwamba z ni barua 26 na f ni 6.

523
00:38:51,340 --> 00:38:55,460
Lakini tuko katika sayansi ya kompyuta, hivyo tunakwenda index saa 0.

524
00:38:55,460 --> 00:39:00,690
Hivyo basi badala ya z kuwa namba 26, sisi ni kwenda kusema idadi ni 25

525
00:39:00,690 --> 00:39:02,630
kwa sababu ni 0.

526
00:39:02,630 --> 00:39:04,770
Hivyo sasa hebu kuomba hii formula.

527
00:39:04,770 --> 00:39:11,710
Tuna z kuwakilishwa na 25 + 6, ambayo inakupa 31.

528
00:39:11,710 --> 00:39:15,790
Na 31 Mod 26 inakupa 5 kama salio.

529
00:39:15,790 --> 00:39:20,500
Hiyo ni kamili kwa sababu tunajua kwamba f ni barua 5 katika alfabeti.

530
00:39:20,500 --> 00:39:26,400
Lakini bado ni si f, haki? Ni bado ni si 102.

531
00:39:26,400 --> 00:39:32,730
Hivyo basi kwa pset hii, changamoto itakuwa kujaribu kujua uhusiano

532
00:39:32,730 --> 00:39:36,910
kati ya kuwageuza kati ya maadili haya ASCII na index alfabeti.

533
00:39:36,910 --> 00:39:40,280
Kimsingi, nini utasikia wanataka kufanya, unataka kuanza nje na maadili ASCII,

534
00:39:40,280 --> 00:39:45,390
lakini kisha unataka namna fulani kwamba kutafsiri katika index alfabeti

535
00:39:45,390 --> 00:39:52,610
kisha hesabu herufi gani ni lazima - kimsingi, nini wake herufi index ni

536
00:39:52,610 --> 00:39:57,660
wa tabia cipher - kisha kutafsiri kwamba nyuma ya maadili ASCII.

537
00:39:57,660 --> 00:40:04,870
Hivyo kama wewe mjeledi nje meza yako ASCII, basi kujaribu na kutafuta mahusiano kati ya, wanasema, 102 na 5

538
00:40:04,870 --> 00:40:10,440
au 122 na 25.

539
00:40:12,140 --> 00:40:15,690
Tumekuwa Gotten ufunguo wetu kutoka hoja mstari amri, tumekuwa Gotten maandishi wazi,

540
00:40:15,690 --> 00:40:17,520
tumekuwa enciphered yake.

541
00:40:17,520 --> 00:40:19,820
Sasa wote tuna baki ni magazeti hayo.

542
00:40:19,820 --> 00:40:22,040
Tunaweza kufanya hili michache ya njia tofauti.

543
00:40:22,040 --> 00:40:24,570
Nini tunaweza kufanya ni kweli magazeti kama sisi kwenda pamoja.

544
00:40:24,570 --> 00:40:28,250
Kama sisi iterate juu ya wahusika katika kamba,

545
00:40:28,250 --> 00:40:31,660
tunaweza tu tu magazeti haki basi wakati sisi hesabu yake.

546
00:40:31,660 --> 00:40:36,030
Vinginevyo, unaweza pia kuhifadhi katika safu na kuwa na safu ya wahusika

547
00:40:36,030 --> 00:40:39,280
na mwishoni iterate juu ya safu kwamba nzima na magazeti nje.

548
00:40:39,280 --> 00:40:40,980
Hivyo kuwa na michache ya chaguzi kwa ajili hiyo.

549
00:40:40,980 --> 00:40:47,280
Na kumbuka kwamba% c ni kwenda kuwa placeholder kwa kuchapa tabia.

550
00:40:47,280 --> 00:40:50,420
Hivyo kuna tuna Kaisari, na sasa sisi kuendelea na Vigenere,

551
00:40:50,420 --> 00:40:57,580
ambayo ni sawa na Kaisari lakini kidogo tu ngumu zaidi.

552
00:40:57,580 --> 00:41:03,310
Hivyo kimsingi na Vigenere ni wewe utaenda kupita katika Keyword.

553
00:41:03,310 --> 00:41:06,510
Hivyo badala ya namba, wewe utaenda kuwa na kamba,

554
00:41:06,510 --> 00:41:09,200
na ili kwenda kutenda kama Keyword yako.

555
00:41:09,200 --> 00:41:14,440
Kisha, kama kawaida, wewe ni kwenda kupata haraka kwa ajili ya kamba kutoka kwa mtumiaji

556
00:41:14,440 --> 00:41:19,050
na kisha encipher yake na kisha kuwapa nyuma nakala ya siri.

557
00:41:19,050 --> 00:41:24,650
Hivyo kama nilivyosema, ni sawa sana kwa Kaisari, ila badala ya shifting kwa idadi fulani,

558
00:41:24,650 --> 00:41:30,620
idadi ni kweli kwenda kubadili kila wakati kutoka tabia ya tabia.

559
00:41:30,620 --> 00:41:34,890
Kuwakilisha kwamba idadi halisi kuhama, ni kuwakilishwa na barua keyboard.

560
00:41:34,890 --> 00:41:43,150
Hivyo kama wewe kuingia katika mabadiliko ya, kwa mfano, basi hiyo itakuwa yanahusiana na mabadiliko ya 0.

561
00:41:43,150 --> 00:41:45,900
Hivyo ni tena nyuma index alfabeti.

562
00:41:45,900 --> 00:41:49,100
Nini kinaweza kuwa na manufaa kama wewe ni kuona kwamba sisi ni kweli kushughulika na maadili ASCII

563
00:41:49,100 --> 00:41:51,790
kama vile barua, kama vile index ya alfabeti,

564
00:41:51,790 --> 00:41:58,020
labda kupata au kufanya ASCII yako mwenyewe meza ambayo inaonyesha index herufi ya 25 kupitia 0,

565
00:41:58,020 --> 00:42:03,750
kupitia z, na maadili ASCII ili uweze aina ya kuona uhusiano

566
00:42:03,750 --> 00:42:07,020
na mchoro nje na kujaribu na kupata mwelekeo fulani.

567
00:42:07,020 --> 00:42:11,010
Vile vile, kama wewe walikuwa shifting katika mfano mmoja na f -

568
00:42:11,010 --> 00:42:21,110
na hii ni aidha f lowercase au uppercase - kisha ambayo yanahusiana na 5.

569
00:42:21,110 --> 00:42:24,180
Je, sisi nzuri hadi sasa?

570
00:42:25,770 --> 00:42:30,050
formula kwa Vigenere ni tofauti kidogo.

571
00:42:30,050 --> 00:42:32,960
Kimsingi, unaweza kuona kwamba ni tu kama Kaisari,

572
00:42:32,960 --> 00:42:37,390
isipokuwa tu badala ya k tuna k index j.

573
00:42:37,390 --> 00:42:44,810
Ona kwamba sisi siyo kutumia i kwa sababu kimsingi, urefu wa Keyword

574
00:42:44,810 --> 00:42:49,850
si lazima urefu wa nakala ya siri yetu.

575
00:42:49,850 --> 00:42:56,130
Hii itakuwa ni wazi kidogo wakati tunaona mfano kwamba mimi kuwa na kidogo baadaye.

576
00:42:56,130 --> 00:43:03,160
Kimsingi, kama wewe kuendesha programu yako kwa Keyword ya ohai,

577
00:43:03,160 --> 00:43:08,560
basi hiyo ina maana kwamba kila wakati, ohai ni kwenda na mabadiliko yako.

578
00:43:08,560 --> 00:43:11,060
Hivyo kutegemea na nini nafasi ya wewe ni katika Keyword yako,

579
00:43:11,060 --> 00:43:15,800
utaenda kuhama nakala ya siri yako fulani tabia kwa kiasi hicho.

580
00:43:15,800 --> 00:43:19,630
Tena, kama Kaisari, tunataka kuhakikisha kwamba sisi kuhifadhi mtaji wa mambo

581
00:43:19,630 --> 00:43:22,900
na sisi tu encipher barua, si wahusika au mazingira.

582
00:43:22,900 --> 00:43:26,330
Hivyo kuangalia nyuma kwa Kaisari juu ya majukumu ya kwamba unaweza kuwa kutumika,

583
00:43:26,330 --> 00:43:32,570
njia ambayo wewe kuamua jinsi ya kuhama mambo, na kuomba kwamba kwa mpango wako hapa.

584
00:43:32,570 --> 00:43:35,260
Basi hebu ramani hii nje.

585
00:43:35,260 --> 00:43:39,680
Tuna maandishi wazi kwamba tumekuwa wamezipata kutoka kwa mtumiaji kutoka GetString

586
00:43:39,680 --> 00:43:44,090
akisema huu ... ni CS50!

587
00:43:44,090 --> 00:43:47,090
Basi tuna neno la ufunguo wa ohai.

588
00:43:47,090 --> 00:43:50,930
kwanza 4 wahusika ni pretty rahisi.

589
00:43:50,930 --> 00:43:55,580
Tunajua kwamba T ni kwenda kuwa kubadilishwa kwa o,

590
00:43:55,580 --> 00:44:01,990
kisha h ni kwenda kubadilishwa na h, i ni kwenda kubadilishwa kwa.

591
00:44:01,990 --> 00:44:04,610
Hapa unaweza kuona kwamba inawakilisha 0,

592
00:44:04,610 --> 00:44:11,940
hivyo basi thamani mwisho ni kweli tu barua sawa kabla.

593
00:44:11,940 --> 00:44:15,250
Kisha s ni kubadilishwa kwa i.

594
00:44:15,250 --> 00:44:19,370
Lakini basi una vipindi hivi hapa.

595
00:44:19,370 --> 00:44:25,960
Sisi hatutaki encipher kwamba, hivyo basi hatuwezi kubadilisha kitu chochote na

596
00:44:25,960 --> 00:44:31,280
na tu magazeti nje kipindi unchanged.

597
00:44:31,280 --> 00:44:38,020
[Mwanafunzi] Sielewi jinsi unajua kwamba hii ni kubadilishwa kwa - wapi Ulifanya - >> Oh, sorry.

598
00:44:38,020 --> 00:44:41,620
Saa ya juu hapa unaweza kuona kwamba mstari amri hoja ohai hapa,

599
00:44:41,620 --> 00:44:43,740
kwamba itakuja kuwa Keyword.

600
00:44:43,740 --> 00:44:49,550
Na hivyo kimsingi, wewe baiskeli juu ya wahusika katika Keyword.

601
00:44:49,550 --> 00:44:52,020
[Mwanafunzi] Basi o ni kwenda shifting sawa -

602
00:44:52,020 --> 00:44:56,260
Hivyo o sambamba na idadi fulani katika alfabeti.

603
00:44:56,260 --> 00:44:58,400
[Mwanafunzi] Haki. Lakini wapi kupata sehemu CS50 kutoka?

604
00:44:58,400 --> 00:45:02,540
Oh. Hiyo ni katika GetString ambapo wewe ni kama, "Nipe kamba encode."

605
00:45:02,540 --> 00:45:07,510
[Mwanafunzi] Wao wanaenda kukupa kwamba hoja kuhama kwa

606
00:45:07,510 --> 00:45:09,380
na kisha utasikia kuuliza kwa kamba yako ya kwanza. >> Yeah.

607
00:45:09,380 --> 00:45:12,440
Basi walipo kuendesha programu, wao wanaenda pamoja Keyword

608
00:45:12,440 --> 00:45:14,740
katika amri zao line hoja wakati wao kukimbia.

609
00:45:14,740 --> 00:45:19,740
Kisha mara moja umefanya checked kwamba wameweza kweli kupeni 1 na si zaidi, si chini,

610
00:45:19,740 --> 00:45:23,750
kisha utaenda kuwachochea kwa kamba, wanasema, "Nipe kamba."

611
00:45:23,750 --> 00:45:27,630
Hivyo hiyo ambapo katika kesi hii wameweza kupeni huu ... ni CS50!

612
00:45:27,630 --> 00:45:32,090
Hivyo basi wewe ni kwenda kutumia kwamba na kutumia ohai na iterate juu.

613
00:45:32,090 --> 00:45:38,200
Ona kwamba hapa sisi skipped juu ya encrypting vipindi,

614
00:45:38,200 --> 00:45:51,660
lakini katika suala la msimamo wetu kwa ohai, moja ijayo sisi kutumika o.

615
00:45:51,660 --> 00:45:54,990
Katika kesi hii ni vigumu kidogo kuona kwa sababu hiyo ni 4,

616
00:45:54,990 --> 00:45:57,710
hivyo hebu kuendelea kidogo. Tu fimbo na mimi hapa.

617
00:45:57,710 --> 00:46:02,960
Basi tuna i na s, ambayo ni basi Tafsiri kwa o na h mtiririko huo.

618
00:46:02,960 --> 00:46:09,370
Basi tuna nafasi, na hivyo basi tunajua kwamba sisi si kwenda encipher mazingira.

619
00:46:09,370 --> 00:46:18,930
Lakini ona kwamba badala ya kwenda katika doa haki hii hapa,

620
00:46:18,930 --> 00:46:28,330
tuko encrypting na - mimi sijui kama unaweza kuona kwamba - haki hapa.

621
00:46:28,330 --> 00:46:33,710
Hivyo si kama wewe kweli predetermined, kusema, o huenda hapa, h huenda hapa,

622
00:46:33,710 --> 00:46:39,200
huenda hapa, i huenda hapa, o, h,, i, o, h,, i. Huwezi kufanya hivyo.

623
00:46:39,200 --> 00:46:43,760
Wewe tu kuhama nafasi yako katika Keyword

624
00:46:43,760 --> 00:46:51,020
wakati unajua kwamba wewe ni kweli kwenda kuwa encrypting barua halisi.

625
00:46:51,020 --> 00:46:53,920
Je, hiyo aina ya mantiki?

626
00:46:53,920 --> 00:46:55,800
Sawa.

627
00:46:56,490 --> 00:46:58,500
Hivyo baadhi tu kuwakumbusha.

628
00:46:58,500 --> 00:47:03,760
Wewe unataka kuhakikisha kwamba wewe tu mapema ili barua ijayo katika Keyword yako

629
00:47:03,760 --> 00:47:06,390
kama tabia yako katika maandishi wazi ni barua.

630
00:47:06,390 --> 00:47:09,120
Hivyo kusema sisi ni saa o.

631
00:47:09,120 --> 00:47:19,310
Tunaona kwamba, tabia ijayo, index i wa maandishi wazi, ni idadi, kwa mfano.

632
00:47:19,310 --> 00:47:31,630
Kisha sisi wala kuendeleza j, index kwa Keyword zetu, hata sisi kufikia barua nyingine.

633
00:47:31,630 --> 00:47:36,230
Tena, wewe pia wanataka kuhakikisha kuwa wewe iliyomficha mwanzo wa Keyword

634
00:47:36,230 --> 00:47:37,770
wakati uko katika mwisho wake.

635
00:47:37,770 --> 00:47:42,030
Kama unaweza kuona hapa sisi ni saa i, moja ijayo ina kuwa o.

636
00:47:42,030 --> 00:47:47,690
Hivyo unataka kupata baadhi ya njia ya kuwa na uwezo wa iliyomficha mwanzo wa Keyword yako

637
00:47:47,690 --> 00:47:49,470
kila wakati kwamba kufikia mwisho.

638
00:47:49,470 --> 00:47:55,040
Na hivyo tena, aina gani ya operator ni muhimu katika kesi hiyo kwa wrapping kote?

639
00:47:56,630 --> 00:47:59,840
Kama ilivyo katika kuhesabu mbali mfano.

640
00:47:59,840 --> 00:48:03,710
[Mwanafunzi] ishara asilimia. >> Yeah, ishara asilimia, ambayo ni modulo.

641
00:48:03,710 --> 00:48:11,250
Hivyo modulo atakuja katika Handy hapa wakati unataka wrap juu ya index katika ohai yako.

642
00:48:11,250 --> 00:48:17,700
Na tu ladha haraka: Jaribu kufikiria wrapping zaidi Keyword kidogo kama mbali kuhesabu,

643
00:48:17,700 --> 00:48:23,590
ambapo kama kuna 3 vikundi, mtu 4,

644
00:48:23,590 --> 00:48:30,610
idadi yao kuwa walisema ilikuwa 4 Mod 3, ambayo ilikuwa 1.

645
00:48:30,610 --> 00:48:32,880
Hivyo kujaribu na kufikiria njia hiyo.

646
00:48:34,770 --> 00:48:42,740
Kama wewe aliona katika formula, popote una ci na kisha pi lakini basi KJ,

647
00:48:42,740 --> 00:48:44,700
unataka kuhakikisha kwamba kuweka wimbo wa wale.

648
00:48:44,700 --> 00:48:47,580
Huna haja ya kumwita i, huna haja ya kuiita j,

649
00:48:47,580 --> 00:48:53,270
lakini wewe unataka kuhakikisha kwamba kuweka wimbo wa msimamo kuwa uko katika maandishi wazi katika yako

650
00:48:53,270 --> 00:48:55,790
kama vile nafasi ya kuwa uko katika katika Keyword yako

651
00:48:55,790 --> 00:48:59,840
kwa sababu wale si lazima kwenda kuwa sawa.

652
00:48:59,840 --> 00:49:06,400
Si tu haina Keyword - inaweza kuwa urefu tofauti kabisa kuliko maandishi wazi yako.

653
00:49:06,400 --> 00:49:09,140
Pia, maandishi wazi wako, kuna idadi na wahusika,

654
00:49:09,140 --> 00:49:14,450
hivyo si kwenda kikamilifu match up pamoja. Ndiyo.

655
00:49:14,450 --> 00:49:19,280
[Mwanafunzi] Je, kuna kazi ya kubadilisha kesi?

656
00:49:19,280 --> 00:49:24,530
Je, unaweza kubadilisha mji mkuu? >> Yeah, kuna dhahiri ni.

657
00:49:24,530 --> 00:49:27,890
Unaweza kuangalia - naamini toupper ni, wote neno 1.

658
00:49:30,650 --> 00:49:36,310
Lakini wakati wewe ni kujaribu cipher mambo na kuhifadhi maandishi,

659
00:49:36,310 --> 00:49:39,350
ni bora kimsingi kuwa na kesi tofauti.

660
00:49:39,350 --> 00:49:42,040
Kama ni uppercase, kisha unataka kuhama kwa hii

661
00:49:42,040 --> 00:49:46,460
kwa sababu katika formula yako, wakati ukiangalia nyuma jinsi tuna aina ya go

662
00:49:46,460 --> 00:49:50,900
kubadilishana kati ya njia ASCII ya anayewakilisha idadi

663
00:49:50,900 --> 00:49:55,020
na halisi alfabeti index, tunataka kuhakikisha

664
00:49:55,020 --> 00:50:01,850
kuna kwenda kuwa baadhi ya aina ya muundo kwamba utaenda kutumia.

665
00:50:01,850 --> 00:50:04,580
Mwingine kumbuka juu ya muundo, kwa kweli.

666
00:50:04,580 --> 00:50:07,250
Utaenda dhahiri kuwa kushughulika na idadi.

667
00:50:07,250 --> 00:50:11,280
Jaribu kutumia namba uchawi, ambayo ni mfano wa mtindo.

668
00:50:11,280 --> 00:50:18,470
Hivyo kusema unataka kila kitu wakati kuhama na kama -

669
00:50:18,470 --> 00:50:22,400
Sawa, hivyo ladha, spoiler mwingine ni wakati wewe ni kwenda kuwa kitu shifting

670
00:50:22,400 --> 00:50:26,310
kwa kiasi fulani, jaribu kuwakilisha kwamba kwa idadi halisi

671
00:50:26,310 --> 00:50:32,810
lakini badala ya kujaribu na kuona kama unaweza kutumia thamani ASCII, ambayo itakuwa ya aina ya kufanya zaidi ya akili.

672
00:50:32,810 --> 00:50:35,470
Mwingine kumbuka: Kwa sababu sisi ni kushughulika na formula,

673
00:50:35,470 --> 00:50:41,200
ingawa TF wako aina ya kujua nini mfano unaweza kutumia,

674
00:50:41,200 --> 00:50:44,430
bora katika aina yako maoni ya kueleza mantiki, kama,

675
00:50:44,430 --> 00:50:51,880
"Mimi nina kutumia muundo huu kwa sababu ..." na aina ya kueleza mfano succinctly katika maoni yako.

676
00:50:54,090 --> 00:50:58,990
[Hii ilikuwa walkthrough 2] Kama kuna mtu yoyote maswali mengine, basi mimi itabidi tu kukaa hapa kwa muda kidogo.

677
00:50:58,990 --> 00:51:04,370
Bahati nzuri na pset yako 2: Crypto na shukrani kwa kuja.

678
00:51:06,070 --> 00:51:08,620
[Mwanafunzi] Asante. >> Shukrani.

679
00:51:09,220 --> 00:51:10,800
[Media Offline intro]