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[Powered by Google Translate] [Sehemu ya 6] [Zaidi Starehe]

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[Rob Bowden] [Chuo Kikuu cha Harvard]

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[Hii ni CS50.] [CS50.TV]

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>> Tunaweza kichwa na sehemu yetu ya maswali.

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Mimi nimewatuma URL kwa nafasi kabla.

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mwanzo wa sehemu ya maswali kusema-

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inaonekana mimi si kabisa unsick-ni swali rahisi sana

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ya kile tu ni valgrind?

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Je valgrind kufanya?

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Mtu unataka kusema nini valgrind gani?

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[Mwanafunzi] Checks kumbukumbu uvujaji.

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Yeah, ni valgrind ujumla kumbukumbu kusahihisha.

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Ni, mwisho, anakwambia kama una uvujaji yoyote kumbukumbu,

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ambayo ni zaidi ya kile tunayatumia kwa sababu kama unataka

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kufanya vizuri katika kuweka tatizo au kama unataka

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kupata kwenye bodi kubwa, unahitaji kuwa na uvujaji hakuna kumbukumbu yo yote,

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na katika kesi una leak kumbukumbu kwamba huwezi kupata,

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pia kukumbuka kwamba wakati wowote wewe kufungua faili

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na kama huna kulifunga, hiyo leak kumbukumbu.

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>> mengi ya watu ni kuangalia kwa baadhi nodi kwamba wao siyo kumkomboa

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wakati kwa kweli, hawakuwa karibu kamusi katika hatua ya kwanza kabisa.

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Unakuelekeza pia kama una batili anasoma au anaandika,

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ambayo ina maana kama wewe kujaribu na kuweka thamani

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hiyo ni zaidi ya mwisho wa lundo na haina kutokea kwa kosa seg

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lakini valgrind upatikanaji wa samaki, kama ni lazima si kweli kuwa kuandika huko,

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na hivyo wewe dhahiri wanapaswa kuwa yoyote ya wale aidha.

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Jinsi gani unaweza kutumia valgrind?

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Jinsi gani unaweza kutumia valgrind?

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>> Ni swali ya jumla ya

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aina ya kukimbia na kuangalia pato.

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pato ni balaa mengi ya nyakati.

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Kuna pia furaha makosa ambapo kama una baadhi kitu vibaya sana

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yanayotokea katika kitanzi, kisha hatimaye kusema, "makosa Njia nyingi sana.

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Mimi naenda kuacha kuhesabu sasa. "

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Ni kimsingi textual pato kwamba una kuchanganua.

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Katika mwisho, itakuambia uvujaji yoyote kumbukumbu kwamba una,

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wangapi vitalu, ambayo inaweza kuwa na manufaa kwa sababu

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ikiwa ni moja ya kuzuia unfreed, basi ni kawaida rahisi kupata

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kuliko 1000 vitalu unfreed.

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1000 vitalu unfreed pengine ina maana wewe si kumkomboa

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orodha yako wanaohusishwa ipasavyo au kitu.

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Hiyo valgrind.

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>> Sasa tuna sehemu yetu ya maswali,

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ambayo huna haja ya shusha.

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Unaweza bonyeza juu ya jina langu na kuvuta yao juu katika nafasi.

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Sasa bonyeza yangu.

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Marekebisho 1 itakuwa stack, ambayo sisi ni kufanya kwanza.

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Marekebisho 2 itakuwa foleni, na Revision 3 itakuwa moja moja wanaohusishwa orodha.

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Kuanzia mbali na stack yetu.

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Kama anasema hapa, stack ni moja ya msingi zaidi,

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msingi data miundo ya sayansi ya kompyuta.

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mfano sana prototypical ni

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stack ya trays katika ukumbi dining.

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Ni kimsingi wakati wewe ni kuwa ilianzisha stack,

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mtu ni kwenda kusema, "Oh, kama stack ya trays."

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Wewe stack trays up.

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Kisha wakati wa kwenda kuvuta tray,

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tray kwanza hiyo kupata vunjwa ni moja ya mwisho kwamba ilikuwa kuweka juu ya stack.

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stack pia-kama inavyosema hapa-

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tuna sehemu ya kumbukumbu ya kuitwa stack.

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Na ni kwa nini inaitwa stack?

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>> Kwa sababu, kama muundo stack data,

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inasukuma na POP muafaka stack juu ya stack,

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ambapo muafaka stack ni kama wito maalum wa kazi.

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Na kama stack, utakuwa daima kuwa na kurudi

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kutoka kwa mwito wa kazi kabla ya wewe wanaweza kupata chini ndani ya muafaka chini stack tena.

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Huwezi kuwa kuu wito foo wito bar na kurudi bar moja kwa moja kuu.

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Ni daima got kufuata stack sahihi kusukuma na popping.

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shughuli mbili, kama nilivyosema, ni kushinikiza na pop.

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Wale ni zima masharti.

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Unapaswa kujua kushinikiza na pop katika suala la mwingi bila kujali.

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Tutaweza kuona foleni ni aina ya tofauti.

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Ni kweli haina muda wote, lakini msukumo na pop ni zima kwa mwingi.

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Push ni kuweka tu juu ya stack.

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Picha ni kuchukua mbali stack.

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Na tunaona hapa tuna struct wetu typedef stack,

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hivyo tuna masharti Char **.

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Msitishwe kwa ** yoyote.

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Hii ni kwenda kuishia kuwa safu ya masharti

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au safu ya kuyatumia kwa wahusika, ambapo

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kuyatumia kwa wahusika huwa na kuwa masharti.

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Haina kuwa masharti, lakini hapa, wao wanaenda kuwa masharti.

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>> Tuna safu ya masharti.

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Tuna kawaida, ambayo inawakilisha jinsi wengi mambo ni sasa juu ya stack,

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na kisha tuna uwezo, ambayo ni wangapi vipengele inaweza kuwa juu ya stack.

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uwezo wanapaswa kuanza mbali kama kitu zaidi ya 1,

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lakini ukubwa ni kwenda kuanza off kama 0.

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Sasa, kuna kimsingi tatu tofauti ambazo unaweza kufikiri ya stack.

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Naam, kuna pengine zaidi, lakini njia mbili kuu ni

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unaweza kutekeleza ni kutumia safu, au unaweza kutekeleza ni kutumia orodha zinazoungwa.

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Wanaohusishwa orodha ni aina ya trivial kufanya mwingi kutoka.

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Ni rahisi sana kufanya stack kutumia orodha zilizounganishwa,

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hivyo hapa, sisi ni kwenda kufanya stack kutumia arrays,

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na kisha kwa kutumia arrays, pia kuna njia mbili unaweza kufikiri juu yake.

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Kabla ya hapo, mimi alisema tuna uwezo kwa stack,

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hivyo tunaweza fit kipengele juu ya stack.

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>> njia moja inaweza kutokea ni haraka kama wewe hit vipengele 10, basi wewe ni kosa.

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Unaweza kujua kwamba kuna ghorofani amefungwa ya mambo 10 katika ulimwengu

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kwamba hutaweza kuwa na mambo zaidi ya 10 juu ya stack yako,

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katika kesi ambayo unaweza kuwa juu amefungwa juu ya ukubwa wa stack yako.

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Au unaweza kuwa na stack yako kuwa unbounded,

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lakini kama wewe ni kufanya safu, hiyo ina maana kwamba kila wakati wewe hit vipengele 10,

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basi wewe ni kwenda na kukua kwa vipengele 20, na wakati hit vipengele 20,

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wewe utaenda kuwa na kukua safu yako ya vipengele 30 au vipengele 40.

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Wewe ni kwenda haja ya kuongeza uwezo, ambayo ni nini tunakwenda kufanya hapa.

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Kila wakati sisi kufikia upeo wa ukubwa wa stack yetu,

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wakati sisi kushinikiza juu ya kitu kingine, sisi ni kwenda haja ya kuongeza uwezo.

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Hapa, tuna msukumo alitangaza kama kushinikiza bool (Char * str).

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Char * str ni string kwamba sisi ni kusukuma kwenye stack,

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na bool tu anasema iwapo sisi ilifanikiwa au alishindwa.

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>> Tutashindwaje?

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Je, ni hali tu kwamba unaweza kufikiria

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ambapo tunataka haja ya kurudi uongo?

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Yeah.

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[Mwanafunzi] Kama ni kamili na sisi ni kutumia utekelezaji imepakana.

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Yeah, hivyo ni jinsi gani sisi define-yeye akajibu

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kama ni kamili na sisi ni kutumia utekelezaji imepakana.

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Kisha sisi dhahiri kurudi uongo.

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Haraka kama sisi hit mambo 10 katika safu, hatuwezi fit 11, hivyo sisi kurudi uongo.

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Nini kama ni unbounded? Yeah.

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Kama huwezi kupanua safu kwa sababu fulani.

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Yeah, hivyo kumbukumbu ni rasilimali mdogo,

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na hatimaye, kama sisi kuweka mambo kusukuma kwenye stack tena na tena,

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sisi ni kwenda kujaribu na kutenga safu kubwa ya kifafa

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uwezo mkubwa zaidi, na malloc au chochote sisi ni kutumia ni kwenda na kurudi uongo.

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Naam, malloc atarudi null.

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>> Kumbuka, kila wakati milele kupiga malloc, unapaswa kuwa kuangalia ili kuona kama

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anarudi null au mwingine kwamba ni punguzo usahihi.

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Tangu tunataka kuwa na stack unbounded,

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Kesi tu tunakwenda tunarudi uongo ni kama tutajaribu

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kuongeza uwezo na malloc au chochote anarudi uongo.

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Kisha pop inachukua hoja hakuna,

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na kuirudisha string kwamba ni juu ya stack.

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Chochote alikuwa hivi karibuni juu ya kusukuma stack ni nini pop ni kurudi,

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na pia kuondosha ni kutoka stack.

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Na taarifa kwamba kuirudisha null kama kuna chochote juu ya stack.

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Daima ni kwamba inawezekana stack ni tupu.

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Katika Java, kama wewe ni kutumika kwamba, au lugha nyingine,

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kujaribu pop kutoka stack tupu inaweza kusababisha ubaguzi au kitu.

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>> Lakini katika C, null ni aina ya mengi ya matukio jinsi sisi kushughulikia matatizo haya.

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Msimamizi wa null ni jinsi tunakwenda yanamaanisha kwamba stack ilikuwa tupu.

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Tumekuwa zinazotolewa kificho kwamba mtihani utendaji stack yako,

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kutekeleza kushinikiza na pop.

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Hii haitakuwa mengi ya code.

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Nami-kweli, kabla ya sisi kufanya hivyo, ladha, ladha-

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kama si kuiona, malloc si kazi tu

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kwamba inatenga kumbukumbu juu ya lundo kwa ajili yenu.

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Kuna familia ya kazi alloc.

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kwanza ni malloc, ambayo wewe ni kutumika.

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Kisha kuna calloc, ambayo haina kitu kimoja kama malloc,

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lakini itakuwa sifuri kila kitu kwa ajili yenu.

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Kama ve milele alitaka kuweka kila kitu kwa null baada mallocing kitu

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unapaswa kuwa tu kutumika calloc katika nafasi ya kwanza badala ya kuandika

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kwa kitanzi kwa sifuri nje block nzima ya kumbukumbu.

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>> Realloc ni kama malloc na ina mengi ya matukio maalum,

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lakini kimsingi nini realloc gani ni

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inachukua pointer kwamba alikuwa tayari zimetengwa.

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Realloc ni kazi unataka kulipa kipaumbele hapa.

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Inachukua pointer kwamba alikuwa tayari kurudi kutoka malloc.

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Hebu sema wewe kuomba kutoka malloc pointer ya ka 10.

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Kisha baadaye wewe kutambua alitaka ka 20,

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hivyo wewe piga juu ya realloc kwamba pointer na ka 20,

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na realloc moja kwa moja nakala juu ya kila kitu kwa ajili yenu.

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Kama wewe tu kuitwa malloc tena, kama nina block ya ka 10.

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Sasa mimi haja block ya ka 20,

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hivyo kama mimi malloc ka 20, basi nina manually nakala zaidi ya ka 10 ni kitu cha kwanza

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katika jambo la pili na kisha bure jambo la kwanza.

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Realloc kushughulikia kwamba kwa ajili yenu.

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>> Notice signature ni kwenda kuwa utupu *,

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ambayo ni haki ya kurudi pointer block ya kumbukumbu,

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kisha utupu * PTR.

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Unaweza kufikiri ya * utupu kama pointer generic.

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Kwa ujumla, kamwe kukabiliana na * batili,

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lakini malloc ni kurudi * batili, na kisha ni kutumika tu kama

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hii ni kweli kwenda kuwa * Char.

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uliopita utupu * ambayo yamekuwa akarudi na malloc

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sasa inaenda kuwa kupita kwa realloc, na kisha ukubwa

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ni idadi mpya ya ka unataka kutenga, hivyo uwezo wako mpya.

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Mimi nitakupa dakika kadhaa, na kufanya hivyo katika nafasi yetu.

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Anza na Revision 1.

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Mimi nitaacha wewe baada hopefully kuhusu muda wa kutosha wa kutekeleza kushinikiza,

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na kisha mimi nitakupa mwingine mapumziko kufanya pop.

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Lakini ni kweli si kwamba code sana wakati wote.

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code zaidi pengine ni mambo kupanua, kupanua uwezo.

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Sawa, hakuna shinikizo kabisa kufanyika,

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lakini muda mrefu kama wewe kujisikia kama uko kwenye njia ya haki, kwamba ni vizuri.

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>> Je, mtu yeyote yoyote code wao kujisikia vizuri na mimi kuunganisha up?

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Yeah, mimi, bali haina mtu yeyote yoyote code naweza kuvuta up?

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Sawa, unaweza kuanza, ila it, chochote ni?

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Mimi daima kusahau kwamba hatua.

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Okay, kuangalia kushinikiza,

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unataka kueleza code yako?

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[Mwanafunzi] Awali ya yote, mimi kuongezeka ukubwa.

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Nadhani labda mimi lazima kuwa na kwamba-anyway, mimi kuongezeka ukubwa,

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na mimi kuona kama ni chini ya uwezo.

196
00:13:31,000 --> 00:13:36,000
Na kama ni chini ya uwezo, mimi kuongeza safu ya kwamba tayari tunao.

197
00:13:36,000 --> 00:13:42,000
Na kama siyo, mimi nitaongeza uwezo kwa 2,

198
00:13:42,000 --> 00:13:50,000
na mimi reallocate safu masharti kwa kitu fulani na ukubwa kubwa uwezo sasa.

199
00:13:50,000 --> 00:13:55,000
Na kisha kama kwamba inashindwa, nawaambia mtumiaji na kurudi uongo,

200
00:13:55,000 --> 00:14:04,000
na ikiwa ni faini, basi mimi kuweka kamba katika doa mpya.

201
00:14:04,000 --> 00:14:07,000
>> [Rob B.] Pia taarifa kwamba sisi kutumika nzuri bitwise operator hapa

202
00:14:07,000 --> 00:14:09,000
kuzidisha kwa 2.

203
00:14:09,000 --> 00:14:11,000
Kumbuka, kuhama kushoto ni daima kwenda tele kwa 2.

204
00:14:11,000 --> 00:14:15,000
Kuhama haki ni kugawanywa na 2 kwa muda mrefu kama wewe kumbuka kwamba ina maana

205
00:14:15,000 --> 00:14:18,000
kugawanya na 2 kama katika integer kugawanywa na 2.

206
00:14:18,000 --> 00:14:20,000
Ni wanaweza butu 1 hapa au pale.

207
00:14:20,000 --> 00:14:26,000
Lakini mabadiliko ya kushoto na 1 daima ni kwenda kuwa kuyagawa kwa 2,

208
00:14:26,000 --> 00:14:32,000
isipokuwa wewe kufurika mipaka ya integer, na basi itakuwa si kuwa.

209
00:14:32,000 --> 00:14:34,000
maoni upande.

210
00:14:34,000 --> 00:14:39,000
Mimi kama kufanya-hii si kwenda na mabadiliko ya coding njia yoyote chochote,

211
00:14:39,000 --> 00:14:48,000
lakini mimi kama kwa kufanya kitu kama hiki.

212
00:14:48,000 --> 00:14:51,000
Ni kweli ni kwenda kufanya ni kidogo tena.

213
00:15:04,000 --> 00:15:08,000
Labda hii si kesi kamili kuonyesha hili,

214
00:15:08,000 --> 00:15:14,000
lakini mimi kama sehemu ya ndani ya vitalu haya ya-

215
00:15:14,000 --> 00:15:17,000
sawa, kama hii ikiwa ikitokea, basi mimi naenda kufanya kitu fulani,

216
00:15:17,000 --> 00:15:19,000
na kisha kazi ni kosa.

217
00:15:19,000 --> 00:15:22,000
Mimi hawana haja ya basi kitabu macho yangu njia yote chini kazi

218
00:15:22,000 --> 00:15:25,000
kuona nini kinatokea baada ya mwingine.

219
00:15:25,000 --> 00:15:27,000
Ni kama hii ikiwa ikitokea, basi mimi tu kurudi.

220
00:15:27,000 --> 00:15:30,000
Ni pia ina nice aliongeza faida ya kila kitu zaidi ya hii

221
00:15:30,000 --> 00:15:33,000
sasa ni kubadilishwa kushoto mara moja.

222
00:15:33,000 --> 00:15:40,000
Mimi hakuna haja tena-kama wewe milele karibu ridiculously mrefu mistari,

223
00:15:40,000 --> 00:15:45,000
kisha wale ka 4 inaweza kusaidia, na pia kitu zaidi ni kushoto,

224
00:15:45,000 --> 00:15:48,000
chini kuzidiwa unaweza kujisikia kama kama-sawa, mimi na kukumbuka

225
00:15:48,000 --> 00:15:53,000
Mimi nina sasa katika kitanzi wakati ndani ya ndani ya mwingine wa kwa kitanzi.

226
00:15:53,000 --> 00:15:58,000
Popote unaweza kufanya hivyo kurudi mara moja, mimi aina ya kama.

227
00:15:58,000 --> 00:16:05,000
Ni kabisa hiari na si inatarajiwa kwa njia yoyote.

228
00:16:05,000 --> 00:16:12,000
>> [Mwanafunzi] kuwe kawaida - katika hali ya kushindwa?

229
00:16:12,000 --> 00:16:19,000
hali ya kushindwa hapa ni sisi kushindwa realloc, hivyo ndiyo.

230
00:16:19,000 --> 00:16:22,000
Angalia jinsi katika hali ya kushindwa, labda,

231
00:16:22,000 --> 00:16:26,000
isipokuwa sisi bure stuff baadaye, sisi ni daima kwenda kushindwa

232
00:16:26,000 --> 00:16:29,000
hakuna jambo mara ngapi sisi kujaribu kushinikiza kitu.

233
00:16:29,000 --> 00:16:32,000
Kama tutaendelea kusukuma, sisi kuendelea incrementing kawaida,

234
00:16:32,000 --> 00:16:36,000
ingawa sisi si kuweka kitu chochote kwenye stack.

235
00:16:36,000 --> 00:16:39,000
Kawaida hatuwezi increment ukubwa mpaka

236
00:16:39,000 --> 00:16:43,000
baada tumefanikiwa kuweka kwenye stack.

237
00:16:43,000 --> 00:16:50,000
Tunataka kufanya hivyo, wanasema, aidha hapa na hapa.

238
00:16:50,000 --> 00:16:56,000
Na kisha badala ya kusema s.size ≤ uwezo, ni chini ya uwezo,

239
00:16:56,000 --> 00:17:01,000
tu kwa sababu sisi wakiongozwa ambapo kila kitu kilikuwa.

240
00:17:01,000 --> 00:17:07,000
>> Na kumbuka, mahali tu kwamba sisi inaweza uwezekano kurudi uongo

241
00:17:07,000 --> 00:17:14,000
ni hapa, ambapo realloc akarudi null,

242
00:17:14,000 --> 00:17:19,000
na kama kutokea kwa kukumbuka makosa ya hali,

243
00:17:19,000 --> 00:17:22,000
labda unaweza kufikiria kesi hii ambapo unataka magazeti makosa ya hali,

244
00:17:22,000 --> 00:17:26,000
hivyo fprintf stderr badala ya kuchapa moja kwa moja na nje ya kiwango.

245
00:17:26,000 --> 00:17:31,000
Tena, kwamba si matumaini, lakini kama ni makosa,

246
00:17:31,000 --> 00:17:41,000
aina printf, basi unaweza wanataka kufanya hivyo magazeti kwa makosa ya hali badala ya nje ya kiwango.

247
00:17:41,000 --> 00:17:44,000
>> Mtu yeyote kuwa kitu kingine kukumbuka? Ndiyo.

248
00:17:44,000 --> 00:17:47,000
[Mwanafunzi] Je, unaweza kwenda zaidi ya [inaudible]?

249
00:17:47,000 --> 00:17:55,000
[Rob B.] Ndiyo, binariness wake halisi au tu ni nini?

250
00:17:55,000 --> 00:17:57,000
[Mwanafunzi] Basi wewe kuzidisha ni kwa 2?

251
00:17:57,000 --> 00:17:59,000
[Rob B.] Yeah, kimsingi.

252
00:17:59,000 --> 00:18:11,000
Katika nchi binary, sisi daima kuwa kuweka wetu wa tarakimu.

253
00:18:11,000 --> 00:18:22,000
Shifting hii kushoto na 1 kimsingi kuwekeza hapa upande wa kulia.

254
00:18:22,000 --> 00:18:25,000
Rudi hii, tu kukumbuka kwamba kila kitu katika binary

255
00:18:25,000 --> 00:18:28,000
ni nguvu ya 2, hivyo hii inawakilisha 2-0,

256
00:18:28,000 --> 00:18:30,000
hii 2-1, hii 2-2.

257
00:18:30,000 --> 00:18:33,000
Kwa kuingiza 0 kwa upande wa kulia sasa, sisi tu kuhama kila kitu juu.

258
00:18:33,000 --> 00:18:38,000
Nini kutumika kuwa 2-0 ni sasa 2-1, ni 2-2.

259
00:18:38,000 --> 00:18:41,000
upande wa kulia kwamba sisi kuingizwa

260
00:18:41,000 --> 00:18:44,000
ni lazima itakuwa 0,

261
00:18:44,000 --> 00:18:46,000
ambayo hufanya akili.

262
00:18:46,000 --> 00:18:49,000
Kama umewahi kuzidisha idadi na 2, si kwenda kuishia isiyo ya kawaida,

263
00:18:49,000 --> 00:18:54,000
hivyo 2 mahali 0 lazima 0,

264
00:18:54,000 --> 00:18:59,000
na hii ni kile nusu alionya kuhusu kabla ni kama huna kutokea kuhama

265
00:18:59,000 --> 00:19:01,000
zaidi ya idadi ya sarafu katika integer,

266
00:19:01,000 --> 00:19:04,000
kisha 1 huu ni kwenda kuishia kwenda mbali.

267
00:19:04,000 --> 00:19:10,000
Hiyo tu wasiwasi kama kutokea kwa kuwa kushughulika na uwezo kweli kubwa.

268
00:19:10,000 --> 00:19:15,000
Lakini katika hatua hiyo, basi wewe ni kushughulika na safu ya mabilioni ya mambo,

269
00:19:15,000 --> 00:19:25,000
ambayo inaweza kufaa katika kumbukumbu anyway.

270
00:19:25,000 --> 00:19:31,000
>> Sasa tunaweza kupata pop, ambayo ni rahisi hata.

271
00:19:31,000 --> 00:19:36,000
Unaweza kufanya hivyo kama kama wewe kutokea pop rundo zima,

272
00:19:36,000 --> 00:19:38,000
na sasa uko katika uwezo nusu tena.

273
00:19:38,000 --> 00:19:42,000
Unaweza realloc shrink kiasi cha kumbukumbu una,

274
00:19:42,000 --> 00:19:47,000
lakini huna na wasiwasi juu ya kwamba, hivyo tu realloc kesi ni kwenda kuwa

275
00:19:47,000 --> 00:19:50,000
kuongezeka kumbukumbu, kamwe kushuka kumbukumbu,

276
00:19:50,000 --> 00:19:59,000
ambayo ni kwenda kufanya super pop rahisi.

277
00:19:59,000 --> 00:20:02,000
Sasa foleni, ambayo ni kwenda kuwa kama mwingi,

278
00:20:02,000 --> 00:20:06,000
lakini ili kwamba kuchukua mambo ya nje ni kuachwa.

279
00:20:06,000 --> 00:20:10,000
Mfano wa foleni ni mstari,

280
00:20:10,000 --> 00:20:12,000
hivyo mimi nadhani kama ungekuwa Kiingereza, napenda kuwa alisema

281
00:20:12,000 --> 00:20:17,000
Mfano wa foleni ni foleni.

282
00:20:17,000 --> 00:20:22,000
Hivyo kama mstari, kama wewe ni mtu wa kwanza katika mstari,

283
00:20:22,000 --> 00:20:24,000
wanatarajia kuwa mtu wa kwanza nje ya mstari.

284
00:20:24,000 --> 00:20:31,000
Kama wewe ni mtu wa mwisho katika mstari, wewe ni kwenda kuwa mtu wa mwisho serviced.

285
00:20:31,000 --> 00:20:35,000
Tunatoa wito kuwa mfano FIFO, ambapo ilikuwa stack LIFO mfano.

286
00:20:35,000 --> 00:20:40,000
Wale maneno ni pretty zima.

287
00:20:40,000 --> 00:20:46,000
>> Kama mwingi na tofauti na arrays, foleni kawaida hawana kuruhusu upatikanaji wa vipengele katika katikati.

288
00:20:46,000 --> 00:20:50,000
Hapa, stack, tuna msukumo na pop.

289
00:20:50,000 --> 00:20:54,000
Hapa, sisi kutokea kwa niliyowaitia enqueue na dequeue.

290
00:20:54,000 --> 00:20:58,000
Mimi pia aliwasikia kuitwa kuhama na unshift.

291
00:20:58,000 --> 00:21:02,000
Nimesikia watu wakisema kushinikiza na pop na pia yanahusu foleni.

292
00:21:02,000 --> 00:21:05,000
Nimesikia Insert, kuondoa,

293
00:21:05,000 --> 00:21:11,000
hivyo kushinikiza na pop, kama wewe ni kuzungumza juu mwingi, wewe ni kusukuma na popping.

294
00:21:11,000 --> 00:21:16,000
Kama wewe ni kuzungumza kuhusu foleni, unaweza kuchukua maneno unataka kutumia

295
00:21:16,000 --> 00:21:23,000
kwa Infogande na kuondolewa, na hakuna makubaliano juu ya kile lazima kuitwa.

296
00:21:23,000 --> 00:21:27,000
Lakini hapa, tuna enqueue na dequeue.

297
00:21:27,000 --> 00:21:37,000
Sasa, struct inaonekana karibu kufanana na struct stack.

298
00:21:37,000 --> 00:21:40,000
Lakini tuna kuweka wimbo wa kichwa.

299
00:21:40,000 --> 00:21:44,000
Nadhani anasema chini hapa, lakini kwa nini tunahitaji kichwa?

300
00:21:53,000 --> 00:21:57,000
prototypes kimsingi kufanana na kushinikiza na pop.

301
00:21:57,000 --> 00:21:59,000
Unaweza kufikiria kama msukumo na pop.

302
00:21:59,000 --> 00:22:08,000
Tofauti tu ni pop ni kurudi-badala ya mwisho, ni kurudi kwanza.

303
00:22:08,000 --> 00:22:12,000
2, 1, 3, 4, au kitu.

304
00:22:12,000 --> 00:22:14,000
Na hapa ni mwanzo.

305
00:22:14,000 --> 00:22:17,000
Foleni yetu ni kabisa kamili, hivyo kuna nne vipengele ndani yake.

306
00:22:17,000 --> 00:22:21,000
mwisho wa foleni yetu kwa sasa ni 2,

307
00:22:21,000 --> 00:22:24,000
na sasa sisi kwenda Insert kitu kingine.

308
00:22:24,000 --> 00:22:29,000
>> Wakati tunataka Insert kwamba kitu kingine, nini tulifanya kwa toleo stack

309
00:22:29,000 --> 00:22:36,000
ni sisi kupanuliwa block wetu wa kumbukumbu.

310
00:22:36,000 --> 00:22:40,000
Je, ni tatizo na hili?

311
00:22:40,000 --> 00:22:45,000
[Mwanafunzi] Wewe hoja 2.

312
00:22:45,000 --> 00:22:51,000
Kile alisema kabla kuhusu mwisho wa foleni,

313
00:22:51,000 --> 00:22:57,000
hii haina mantiki kwamba sisi kuanza saa 1,

314
00:22:57,000 --> 00:23:01,000
kisha tunataka dequeue 1, kisha dequeue 3, kisha dequeue 4,

315
00:23:01,000 --> 00:23:05,000
kisha dequeue 2, kisha dequeue hii moja.

316
00:23:05,000 --> 00:23:08,000
Hatuwezi kutumia realloc sasa,

317
00:23:08,000 --> 00:23:11,000
au kwa uchache sana, una matumizi realloc katika njia tofauti.

318
00:23:11,000 --> 00:23:15,000
Lakini pengine lazima sio tu kutumia realloc.

319
00:23:15,000 --> 00:23:18,000
Wewe ni kwenda kuwa na manually nakala ya kumbukumbu yako.

320
00:23:18,000 --> 00:23:21,000
>> Kuna kazi mbili kunakili kumbukumbu.

321
00:23:21,000 --> 00:23:25,000
Kuna memcopy na memmove.

322
00:23:25,000 --> 00:23:29,000
Mimi sasa kusoma kurasa mtu kuona ambayo moja wewe ni kwenda unataka kutumia.

323
00:23:29,000 --> 00:23:35,000
Okay, memcopy, tofauti ni

324
00:23:35,000 --> 00:23:38,000
kwamba memcopy na memmove, mmoja Hushughulikia kesi usahihi

325
00:23:38,000 --> 00:23:41,000
ambapo wewe ni kuiga katika kanda ambayo hufanyika na hufunika kanda

326
00:23:41,000 --> 00:23:46,000
wewe ni kuiga kutoka.

327
00:23:46,000 --> 00:23:50,000
Memcopy haina kushughulikia hilo. Memmove gani.

328
00:23:50,000 --> 00:23:59,000
Unaweza kufikiri ya tatizo kama-

329
00:23:59,000 --> 00:24:09,000
hebu sema nataka nakala hii guy,

330
00:24:09,000 --> 00:24:13,000
hizi nne kwa this guy zaidi.

331
00:24:13,000 --> 00:24:16,000
Katika mwisho, nini safu inapaswa kuangalia kama

332
00:24:16,000 --> 00:24:26,000
baada ya nakala ni 2, 1, 2, 1, 3, 4, na kisha baadhi ya mambo mwishoni.

333
00:24:26,000 --> 00:24:29,000
Lakini hii ni tegemezi kwa utaratibu ambao sisi kweli nakala,

334
00:24:29,000 --> 00:24:32,000
tangu kama hatuwezi kufikiria ukweli kwamba mkoa tuko ndani ya kuiga

335
00:24:32,000 --> 00:24:35,000
overlaps moja tuko kuiga kutoka,

336
00:24:35,000 --> 00:24:46,000
basi tunaweza kufanya kama mwanzo hapa, nakala 2 ndani ya mahali tunataka kwenda,

337
00:24:46,000 --> 00:24:52,000
kisha kuondoka kuyatumia yetu mbele.

338
00:24:52,000 --> 00:24:56,000
>> Sasa sisi ni kwenda kuwa hapa na hapa, na sasa tunataka nakala

339
00:24:56,000 --> 00:25:04,000
this guy juu ya guy hii na hoja kuyatumia yetu mbele.

340
00:25:04,000 --> 00:25:07,000
Nini sisi ni kwenda kuishia kupata ni 2, 1, 2, 1, 2, 1

341
00:25:07,000 --> 00:25:10,000
badala ya 2 inafaa, 1, 2, 1, 3, 4 kwa sababu

342
00:25:10,000 --> 00:25:15,000
2, 1 overrode 3 awali, 4.

343
00:25:15,000 --> 00:25:19,000
Memmove Hushughulikia kwamba usahihi.

344
00:25:19,000 --> 00:25:23,000
Katika kesi hiyo, kimsingi tu daima kutumia memmove

345
00:25:23,000 --> 00:25:26,000
sababu Hushughulikia kwa usahihi.

346
00:25:26,000 --> 00:25:29,000
Ni kawaida haina kufanya yoyote mbaya.

347
00:25:29,000 --> 00:25:32,000
Wazo ni badala ya kuanzia mwanzo na kuiga njia hii

348
00:25:32,000 --> 00:25:35,000
kama sisi tu alifanya hapa, ni kuanza kutoka mwisho na nakala katika,

349
00:25:35,000 --> 00:25:38,000
na katika kesi hiyo, unaweza kamwe kuwa na tatizo.

350
00:25:38,000 --> 00:25:40,000
Kuna utendaji hakuna waliopotea.

351
00:25:40,000 --> 00:25:47,000
Daima kutumia memmove. Kamwe wasiwasi kuhusu memcopy.

352
00:25:47,000 --> 00:25:51,000
Na kwamba ni wapi utaenda kuwa na tofauti memmove

353
00:25:51,000 --> 00:26:01,000
sehemu amefungwa kuzunguka ya foleni yako.

354
00:26:01,000 --> 00:26:04,000
Hakuna wasiwasi kama si kabisa kufanyika.

355
00:26:04,000 --> 00:26:10,000
Hii ni ngumu zaidi kuliko stack, pop kushinikiza, na.

356
00:26:10,000 --> 00:26:15,000
>> Mtu yeyote kuwa yoyote code tunaweza kufanya kazi na?

357
00:26:15,000 --> 00:26:21,000
Hata kama kabisa incomplete?

358
00:26:21,000 --> 00:26:23,000
[Mwanafunzi] Yeah, ni kabisa hayajakamilika, ingawa.

359
00:26:23,000 --> 00:26:27,000
Kabisa incomplete ni faini kwa muda mrefu kama sisi-unaweza kujiokoa marekebisho?

360
00:26:27,000 --> 00:26:32,000
Mimi kusahau kwamba kila wakati.

361
00:26:32,000 --> 00:26:39,000
Okay, kupuuza kile kinachotokea wakati tunahitaji resize mambo.

362
00:26:39,000 --> 00:26:42,000
Kabisa kupuuza resize.

363
00:26:42,000 --> 00:26:49,000
Eleza kanuni hii.

364
00:26:49,000 --> 00:26:54,000
Mimi nina kuangalia kwanza ya yote kama kawaida ni chini ya nakala ya kwanza ya yote

365
00:26:54,000 --> 00:27:01,000
na kisha baada ya mimi Insert-Mimi kuchukua kichwa + ukubwa,

366
00:27:01,000 --> 00:27:05,000
na mimi kuhakikisha Wraps kuzunguka uwezo wa safu,

367
00:27:05,000 --> 00:27:08,000
na mimi Insert string mpya katika nafasi hiyo.

368
00:27:08,000 --> 00:27:12,000
Kisha mimi kuongeza ukubwa na kurudi kweli.

369
00:27:12,000 --> 00:27:22,000
>> [Rob B.] Hii ni dhahiri moja ya kesi hizo ambapo utaenda wanataka kutumia Mod.

370
00:27:22,000 --> 00:27:25,000
Aina yoyote ya kesi ambapo una wrapping kote, ikiwa unafikiri wrapping kote,

371
00:27:25,000 --> 00:27:29,000
mawazo ya haraka lazima Mod.

372
00:27:29,000 --> 00:27:36,000
Kama optimization haraka / kufanya code yako mstari mmoja mfupi,

373
00:27:36,000 --> 00:27:42,000
taarifa kwamba line mara baada ya hii moja

374
00:27:42,000 --> 00:27:53,000
ni tu ukubwa + +, hivyo kuunganisha kwamba katika mstari huu, ukubwa + +.

375
00:27:53,000 --> 00:27:58,000
Sasa chini hapa, tuna kesi

376
00:27:58,000 --> 00:28:01,000
ambapo hatuna kumbukumbu ya kutosha,

377
00:28:01,000 --> 00:28:05,000
hivyo sisi ni kuongeza uwezo wetu kwa 2.

378
00:28:05,000 --> 00:28:09,000
Nadhani unaweza kuwa na tatizo moja hapa, lakini hatuwezi kupuuza sasa,

379
00:28:09,000 --> 00:28:13,000
ambapo kama umeshindwa kuongeza uwezo wako,

380
00:28:13,000 --> 00:28:18,000
basi wewe ni kwenda kutaka kupunguza uwezo wako na 2 tena.

381
00:28:18,000 --> 00:28:24,000
Mwingine note mfupi ni kama tu unaweza kufanya + =,

382
00:28:24,000 --> 00:28:30,000
unaweza pia kufanya << =.

383
00:28:30,000 --> 00:28:43,000
Karibu chochote unaweza kwenda mbele sawa, + =, | =, & =, << =.

384
00:28:43,000 --> 00:28:52,000
Char * mpya ni ya kuzuia wetu mpya wa kumbukumbu.

385
00:28:52,000 --> 00:28:55,000
Oh, zaidi ya hapa.

386
00:28:55,000 --> 00:29:02,000
>> Nini watu wanadhani kuhusu aina ya kuzuia wetu mpya wa kumbukumbu?

387
00:29:02,000 --> 00:29:06,000
[Mwanafunzi] Ni lazima Char **.

388
00:29:06,000 --> 00:29:12,000
Kufikiri nyuma struct yetu hapa juu,

389
00:29:12,000 --> 00:29:14,000
masharti ni nini sisi ni reallocating.

390
00:29:14,000 --> 00:29:21,000
Sisi ni maamuzi mzima mpya nguvu kwa ajili ya kuhifadhi mambo katika foleni.

391
00:29:21,000 --> 00:29:25,000
Nini sisi ni kwenda kuwa kumshirikisha kwa masharti yako ni nini tuko mallocing sasa hivi,

392
00:29:25,000 --> 00:29:30,000
na hivyo mpya ni itakuwa ** Char.

393
00:29:30,000 --> 00:29:34,000
Ni kwenda kuwa safu ya masharti.

394
00:29:34,000 --> 00:29:38,000
Basi ni nini kesi ya chini ambayo tunakwenda kurudi uongo?

395
00:29:38,000 --> 00:29:41,000
[Mwanafunzi] Je, sisi kufanya * Char?

396
00:29:41,000 --> 00:29:44,000
[Rob B.] Ndiyo, nzuri wito.

397
00:29:44,000 --> 00:29:46,000
[Mwanafunzi] Nini ilikuwa hivyo?

398
00:29:46,000 --> 00:29:49,000
[Rob B.] Sisi alitaka kufanya ukubwa wa * Char kwa sababu sisi ni tena-

399
00:29:49,000 --> 00:29:53,000
hii ingekuwa kweli kuwa tatizo kubwa sana kwa sababu sizeof (Char) itakuwa 1.

400
00:29:53,000 --> 00:29:55,000
Sizeof Char * ni kwenda kuwa 4,

401
00:29:55,000 --> 00:29:58,000
hivyo mengi ya mara wakati wewe ni kushughulika na ints,

402
00:29:58,000 --> 00:30:01,000
wewe huwa na kupata mbali na hilo kwa sababu ya ukubwa wa int na ukubwa wa * int

403
00:30:01,000 --> 00:30:04,000
juu ya mfumo wa 32-bit ni kwenda kuwa kitu kimoja.

404
00:30:04,000 --> 00:30:09,000
Lakini hapa, sizeof (Char) na sizeof (Char *) sasa kwenda kuwa kitu kimoja.

405
00:30:09,000 --> 00:30:15,000
>> Je, ni hali ambapo sisi kurudi uongo?

406
00:30:15,000 --> 00:30:17,000
[Mwanafunzi] Mpya ni null.

407
00:30:17,000 --> 00:30:23,000
Yeah, ikiwa ni mpya null, sisi kurudi uongo,

408
00:30:23,000 --> 00:30:34,000
na mimi nina kwenda kutupa chini hapa-

409
00:30:34,000 --> 00:30:37,000
[Mwanafunzi] [inaudible]

410
00:30:37,000 --> 00:30:39,000
[Rob B.] Yeah, hii ni faini.

411
00:30:39,000 --> 00:30:46,000
Unaweza ama kufanya 2 mara uwezo au kuhama uwezo 1 na kisha tu akiweke chini hapa au chochote.

412
00:30:46,000 --> 00:30:52,000
Tutaweza kufanya hivyo kama sisi alikuwa ni.

413
00:30:52,000 --> 00:30:56,000
Uwezo >> = 1.

414
00:30:56,000 --> 00:31:08,000
Na wewe kamwe kwenda kuwa na wasiwasi juu ya kupoteza nafasi ya 1

415
00:31:08,000 --> 00:31:12,000
kwa sababu wewe kushoto kubadilishwa na 1, hivyo mahali 1 ni lazima 0,

416
00:31:12,000 --> 00:31:16,000
hivyo haki shifting na 1, wewe bado itakuwa faini.

417
00:31:16,000 --> 00:31:19,000
[Mwanafunzi] Je, unahitaji kufanya hivyo kabla ya kurudi?

418
00:31:19,000 --> 00:31:29,000
[Rob B.] Ndiyo, hii inafanya kabisa hakuna maana.

419
00:31:29,000 --> 00:31:36,000
>> Sasa kudhani tunakwenda kuishia kurejea kweli hadi mwisho.

420
00:31:36,000 --> 00:31:39,000
njia tunakwenda kufanya memmoves hizi,

421
00:31:39,000 --> 00:31:45,000
tunahitaji kuwa makini na jinsi sisi kufanya nao.

422
00:31:45,000 --> 00:31:50,000
Je, mtu yeyote una mapendekezo yoyote kwa jinsi sisi kufanya nao?

423
00:32:17,000 --> 00:32:21,000
Hapa ni kuanza yetu.

424
00:32:21,000 --> 00:32:28,000
Inevitably, tunataka kuanza tena mwanzoni

425
00:32:28,000 --> 00:32:35,000
na nakala ya mambo katika kutoka huko, 1, 3, 4, 2.

426
00:32:35,000 --> 00:32:41,000
Jinsi gani unaweza kufanya hivyo?

427
00:32:41,000 --> 00:32:52,000
Kwanza, mimi na kuangalia ukurasa mtu kwa memmove tena.

428
00:32:52,000 --> 00:32:57,000
Memmove, utaratibu wa hoja zote ni muhimu.

429
00:32:57,000 --> 00:33:01,000
Tunataka marudio yetu ya kwanza, chanzo pili, ukubwa wa tatu.

430
00:33:01,000 --> 00:33:06,000
Kuna mengi ya kazi ambayo kubadili chanzo na marudio.

431
00:33:06,000 --> 00:33:11,000
Marudio, chanzo huelekea kuwa thabiti kiasi fulani.

432
00:33:17,000 --> 00:33:21,000
Hoja, kile ni kurudi?

433
00:33:21,000 --> 00:33:27,000
Kuirudisha pointer kwa marudio, kwa sababu yoyote unaweza kutaka kuwa.

434
00:33:27,000 --> 00:33:32,000
Siwezi picha kusoma, lakini tunataka kuhamia katika eneo letu.

435
00:33:32,000 --> 00:33:35,000
>> Nini marudio yetu kwenda kuwa?

436
00:33:35,000 --> 00:33:37,000
[Mwanafunzi] Mpya.

437
00:33:37,000 --> 00:33:39,000
[Rob B.] Ndiyo, na ambapo ni sisi kuiga kutoka?

438
00:33:39,000 --> 00:33:43,000
Jambo la kwanza sisi ni kuiga ni hii 1, 3, 4.

439
00:33:43,000 --> 00:33:50,000
Je, ni-hii 1, 3, 4.

440
00:33:50,000 --> 00:33:55,000
Nini ni anuani ya hii 1?

441
00:33:55,000 --> 00:33:58,000
Nini ni anuani ya kwamba 1?

442
00:33:58,000 --> 00:34:01,000
[Mwanafunzi] [inaudible]

443
00:34:01,000 --> 00:34:03,000
[Rob B.] Mkuu + anuani ya kipengele kwanza.

444
00:34:03,000 --> 00:34:05,000
Jinsi gani sisi kupata kipengele kwanza katika safu?

445
00:34:05,000 --> 00:34:10,000
[Mwanafunzi] Foleni.

446
00:34:10,000 --> 00:34:15,000
[Rob B.] Ndiyo, q.strings.

447
00:34:15,000 --> 00:34:20,000
Kumbuka, hapa, kichwa yetu ni 1.

448
00:34:20,000 --> 00:34:24,000
Darn yake. Mimi tu nadhani ni magically-

449
00:34:24,000 --> 00:34:29,000
Hapa, kichwa yetu ni 1. Mimi nina kwenda na mabadiliko ya rangi yangu pia.

450
00:34:29,000 --> 00:34:36,000
Na hapa ni masharti.

451
00:34:36,000 --> 00:34:41,000
Hii, tunaweza ama kuandika ni kama sisi alifanya juu hapa

452
00:34:41,000 --> 00:34:43,000
na vichwa + q.strings.

453
00:34:43,000 --> 00:34:51,000
mengi ya watu pia kuandika & q.strings [kichwa].

454
00:34:51,000 --> 00:34:55,000
Hii si kweli yoyote chini ya ufanisi.

455
00:34:55,000 --> 00:34:58,000
Unaweza kufikiria kama wewe ni dereferencing yake na kisha kupata anuani ya,

456
00:34:58,000 --> 00:35:04,000
lakini compiler ni kwenda kutafsiri kwa nini tulikuwa kabla anyway, q.strings + kichwa.

457
00:35:04,000 --> 00:35:06,000
Aidha njia unataka kufikiria hivyo.

458
00:35:06,000 --> 00:35:11,000
>> Na jinsi gani sisi wengi ka unataka kunakili?

459
00:35:11,000 --> 00:35:15,000
[Mwanafunzi] Uwezo - kichwa.

460
00:35:15,000 --> 00:35:18,000
Uwezo - kichwa.

461
00:35:18,000 --> 00:35:21,000
Na kisha unaweza daima kuandika mfano

462
00:35:21,000 --> 00:35:23,000
kufikiri kama hiyo ni haki.

463
00:35:23,000 --> 00:35:26,000
[Mwanafunzi] Inahitaji kugawanywa na 2 hapo.

464
00:35:26,000 --> 00:35:30,000
Yeah, hivyo mimi nadhani tunaweza kutumia kawaida.

465
00:35:30,000 --> 00:35:35,000
Sisi bado tuna kawaida kuwa-

466
00:35:35,000 --> 00:35:39,000
kutumia ukubwa, tuna kawaida sawa na 4.

467
00:35:39,000 --> 00:35:42,000
Kawaida yetu ni 4. Kichwa yetu ni 1.

468
00:35:42,000 --> 00:35:46,000
Tunataka nakala mambo haya 3.

469
00:35:46,000 --> 00:35:54,000
Hiyo sanity kuangalia kwamba ukubwa - kichwa ni usahihi 3.

470
00:35:54,000 --> 00:35:58,000
Na kuja nyuma hapa, kama sisi alisema kabla,

471
00:35:58,000 --> 00:36:00,000
kama sisi kutumika uwezo, basi tunatarajia kuwa kwa kugawanya na 2

472
00:36:00,000 --> 00:36:04,000
kwa sababu tumekuwa tayari mzima uwezo wetu, hivyo badala yake, sisi ni kwenda kutumia kawaida.

473
00:36:11,000 --> 00:36:13,000
Hiyo nakala kwamba sehemu.

474
00:36:13,000 --> 00:36:18,000
Sasa, sisi haja ya kunakili sehemu nyingine, sehemu iliyosalia ya mwanzo.

475
00:36:18,000 --> 00:36:28,000
>> Hiyo inaenda memmove katika kile msimamo?

476
00:36:28,000 --> 00:36:32,000
[Mwanafunzi] Plus kawaida - kichwa.

477
00:36:32,000 --> 00:36:38,000
Ndiyo, hivyo sisi tayari kunakiliwa katika kawaida - ka kichwa,

478
00:36:38,000 --> 00:36:43,000
na hivyo ambapo tunataka nakala ka iliyobaki ni mpya

479
00:36:43,000 --> 00:36:48,000
na kisha ukubwa bala-vizuri, idadi ya ka tumekuwa tayari kunakiliwa in

480
00:36:48,000 --> 00:36:52,000
Na kisha ambapo ni sisi kuiga kutoka?

481
00:36:52,000 --> 00:36:54,000
[Mwanafunzi] Q.strings [0].

482
00:36:54,000 --> 00:36:56,000
[Rob B.] Ndiyo, q.strings.

483
00:36:56,000 --> 00:37:02,000
Tunaweza aidha kufanya & q.strings [0].

484
00:37:02,000 --> 00:37:05,000
Hii ni kwa kiasi kikubwa chini ya kawaida zaidi kuliko huu.

485
00:37:05,000 --> 00:37:14,000
Kama ni kwenda tu kuwa 0, basi utasikia huwa na kuona q.strings.

486
00:37:14,000 --> 00:37:16,000
Hiyo ambapo sisi ni kuiga kutoka.

487
00:37:16,000 --> 00:37:18,000
Jinsi ka wengi hawana sisi wameondoka kunakili? >> [Mwanafunzi] 10.

488
00:37:18,000 --> 00:37:20,000
Haki.

489
00:37:20,000 --> 00:37:25,000
[Mwanafunzi] Je, tuna kuzidisha 5-10 ukubwa wa mara ka au kitu?

490
00:37:25,000 --> 00:37:30,000
Yeah, hivyo hii ni wapi-nini hasa ni sisi kuiga?

491
00:37:30,000 --> 00:37:32,000
[Mwanafunzi] [inaudible]

492
00:37:32,000 --> 00:37:34,000
Je, ni aina ya kitu sisi ni kuiga?

493
00:37:34,000 --> 00:37:36,000
[Mwanafunzi] [inaudible]

494
00:37:36,000 --> 00:37:41,000
Yeah, hivyo Char * Ni kwamba sisi ni kuiga, hatujui ambapo wale wanaotoka katika.

495
00:37:41,000 --> 00:37:47,000
Naam, uko wapi akizungumzia, kama masharti, sisi kuishia kusukuma ni kwenye foleni

496
00:37:47,000 --> 00:37:49,000
au enqueuing kwenye foleni.

497
00:37:49,000 --> 00:37:51,000
Ambapo wale wanaotoka katika, hatuna wazo.

498
00:37:51,000 --> 00:37:56,000
Sisi tu haja ya kuweka wimbo wa Char * s wenyewe.

499
00:37:56,000 --> 00:38:00,000
Hatutaki nakala kawaida - kichwa ka.

500
00:38:00,000 --> 00:38:03,000
Tunataka nakala kawaida - kichwa Char * s,

501
00:38:03,000 --> 00:38:11,000
hivyo tunakwenda kuzidisha hili kwa sizeof (Char *).

502
00:38:11,000 --> 00:38:17,000
Same chini hapa, kichwa * sizeof (Char *).

503
00:38:17,000 --> 00:38:24,000
>> [Mwanafunzi] Je kuhusu [inaudible]?

504
00:38:24,000 --> 00:38:26,000
Haki hii hapa?

505
00:38:26,000 --> 00:38:28,000
[Mwanafunzi] Hapana, chini ya kwamba, ukubwa - kichwa.

506
00:38:28,000 --> 00:38:30,000
[Rob B.] Haki hii hapa?

507
00:38:30,000 --> 00:38:32,000
Pointer hesabu.

508
00:38:32,000 --> 00:38:35,000
Jinsi pointer arithmetic ni kwenda kufanya kazi ni

509
00:38:35,000 --> 00:38:40,000
ni moja kwa moja humzidishia na ukubwa wa aina ya kwamba sisi ni kushughulika na.

510
00:38:40,000 --> 00:38:46,000
Tu kama zaidi ya hapa, mpya + (ukubwa - kichwa)

511
00:38:46,000 --> 00:38:56,000
ni hasa sawa na [size - kichwa] & mpya

512
00:38:56,000 --> 00:39:00,000
mpaka tunatarajia kwamba kwa kufanya kazi kwa usahihi,

513
00:39:00,000 --> 00:39:04,000
tangu kama sisi ni kushughulika na safu int, basi sisi si index na int-

514
00:39:04,000 --> 00:39:07,000
au kama ni ya ukubwa wa 5 na unataka kipengele 4, basi sisi katika index

515
00:39:07,000 --> 00:39:10,000
int safu [4].

516
00:39:10,000 --> 00:39:14,000
Wewe don't-[4] * ukubwa wa int.

517
00:39:14,000 --> 00:39:21,000
Kwamba Hushughulikia ni moja kwa moja, na hii kesi

518
00:39:21,000 --> 00:39:29,000
ni literally sawa, hivyo syntax bracket

519
00:39:29,000 --> 00:39:34,000
ni kwenda tu kuwa waongofu kwa hii haraka kama wewe kukusanya.

520
00:39:34,000 --> 00:39:38,000
Hiyo ni kitu unahitaji kuwa makini ya kwamba

521
00:39:38,000 --> 00:39:42,000
wakati wewe ni kuongeza ukubwa - kichwa

522
00:39:42,000 --> 00:39:45,000
wewe ni akiongeza si moja Byte.

523
00:39:45,000 --> 00:39:53,000
Wewe ni kuongeza moja Char *, ambayo inaweza kuwa moja ka au chochote.

524
00:39:53,000 --> 00:39:56,000
>> Maswali mengine?

525
00:39:56,000 --> 00:40:04,000
Okay, dequeue ni kwenda kuwa rahisi zaidi.

526
00:40:04,000 --> 00:40:11,000
Mimi nitakupa dakika kutekeleza.

527
00:40:11,000 --> 00:40:18,000
Oh, na mimi nadhani hii ni hali kama hiyo ambapo

528
00:40:18,000 --> 00:40:21,000
nini kesi enqueue, kama sisi ni enqueuing null,

529
00:40:21,000 --> 00:40:24,000
labda tunataka kushughulikia hilo, labda sisi si.

530
00:40:24,000 --> 00:40:27,000
Sisi si kufanya tena hapa, lakini sawa stack kesi yetu.

531
00:40:27,000 --> 00:40:34,000
Kama sisi enqueue null, sisi kutaka kupuuza yake.

532
00:40:34,000 --> 00:40:40,000
Mtu yeyote kuwa baadhi ya kanuni siwezi kuvuta up?

533
00:40:40,000 --> 00:40:45,000
[Mwanafunzi] Mimi tu dequeue.

534
00:40:45,000 --> 00:40:56,000
Version 2 ni kwamba-sawa.

535
00:40:56,000 --> 00:40:59,000
Unataka kueleza?

536
00:40:59,000 --> 00:41:01,000
[Mwanafunzi] Kwanza, kuhakikisha kuna kitu katika foleni

537
00:41:01,000 --> 00:41:07,000
na kwamba ukubwa ni kwenda chini kwa 1.

538
00:41:07,000 --> 00:41:11,000
Unahitaji kufanya hivyo, na kisha kurudi kichwa

539
00:41:11,000 --> 00:41:13,000
na kisha kusonga kichwa up 1.

540
00:41:13,000 --> 00:41:19,000
Okay, kwa hivyo kuna kesi kona tuna kufikiria. Yeah.

541
00:41:19,000 --> 00:41:24,000
[Mwanafunzi] Kama kichwa yako ni katika kipengele mwisho,

542
00:41:24,000 --> 00:41:26,000
basi hutaki kichwa kwa kumweka nje ya safu.

543
00:41:26,000 --> 00:41:29,000
>> Yeah, hivyo kwa haraka kama kichwa hits mwisho wa safu yetu,

544
00:41:29,000 --> 00:41:35,000
wakati sisi dequeue, kichwa zetu zinapaswa modded nyuma 0.

545
00:41:35,000 --> 00:41:40,000
Kwa bahati mbaya, hatuwezi kufanya hivyo katika hatua moja.

546
00:41:40,000 --> 00:41:44,000
Nadhani njia ningependa pengine kurekebisha ni

547
00:41:44,000 --> 00:41:52,000
hii ni kwenda kuwa * Char, nini tuko kurudi,

548
00:41:52,000 --> 00:41:55,000
jina lolote yako variable anataka kuwa.

549
00:41:55,000 --> 00:42:02,000
Kisha tunataka Mod kichwa na uwezo wetu

550
00:42:02,000 --> 00:42:10,000
na kisha kurudi ret.

551
00:42:10,000 --> 00:42:14,000
mengi ya watu hapa wapate kufanya-

552
00:42:14,000 --> 00:42:19,000
hii ni kesi ya-you'll kuona watu kufanya kama kichwa

553
00:42:19,000 --> 00:42:29,000
ni mkubwa kuliko uwezo, kufanya kichwa - uwezo.

554
00:42:29,000 --> 00:42:36,000
Na hiyo tu kazi kuzunguka kile Mod ni.

555
00:42:36,000 --> 00:42:41,000
Mkuu Mod = uwezo ni safi zaidi

556
00:42:41,000 --> 00:42:51,000
ya wrapping karibu zaidi kuliko kama kichwa kubwa kuliko uwezo kichwa - uwezo.

557
00:42:51,000 --> 00:42:56,000
>> Maswali?

558
00:42:56,000 --> 00:43:02,000
Okay, jambo la mwisho tuna kushoto ni orodha yetu na uhusiano nao.

559
00:43:02,000 --> 00:43:07,000
Unaweza kutumika kwa baadhi ya tabia wanaohusishwa orodha kama alivyofanya

560
00:43:07,000 --> 00:43:11,000
wanaohusishwa orodha katika meza yako hash, kama alivyofanya meza hash.

561
00:43:11,000 --> 00:43:15,000
Ninawaasa kufanya meza hash.

562
00:43:15,000 --> 00:43:17,000
Unaweza kuwa tayari amefanya trie,

563
00:43:17,000 --> 00:43:23,000
lakini inajaribu ni magumu zaidi.

564
00:43:23,000 --> 00:43:27,000
Katika nadharia, wao uko asymptotically bora.

565
00:43:27,000 --> 00:43:30,000
Lakini tu kuangalia bodi kubwa,

566
00:43:30,000 --> 00:43:35,000
na inajaribu kamwe kufanya vizuri, na wao kuchukua kumbukumbu zaidi.

567
00:43:35,000 --> 00:43:43,000
Kila kitu kuhusu anajaribu kuishia kuwa mbaya zaidi kwa ajili ya kazi zaidi.

568
00:43:43,000 --> 00:43:49,000
Ni nini ufumbuzi Daudi Malan siku zote ni

569
00:43:49,000 --> 00:43:56,000
ni yeye daima posts ufumbuzi wake trie, na hebu angalia ambapo yeye sasa ni.

570
00:43:56,000 --> 00:44:00,000
Nini ilikuwa chini ya yeye, Daudi J?

571
00:44:00,000 --> 00:44:06,000
Yeye ni # 18, hivyo si kwamba sana mbaya,

572
00:44:06,000 --> 00:44:09,000
na kwamba kinaendelea kuwa moja ya bora inajaribu unaweza kufikiria

573
00:44:09,000 --> 00:44:17,000
au mojawapo ya bora ya anajaribu trie.

574
00:44:17,000 --> 00:44:23,000
Je, ni hata ufumbuzi wake wa awali?

575
00:44:23,000 --> 00:44:29,000
Najisikia kama trie ufumbuzi huwa na kuwa zaidi katika hili mbalimbali ya matumizi ya RAM.

576
00:44:29,000 --> 00:44:33,000
>> Kwenda chini hadi juu sana, na RAM ni matumizi katika tarakimu moja.

577
00:44:33,000 --> 00:44:36,000
Nenda chini kuelekea chini, na kisha wewe kuanza kuona anajaribu

578
00:44:36,000 --> 00:44:41,000
ambapo unaweza kupata kabisa mkubwa RAM matumizi,

579
00:44:41,000 --> 00:44:45,000
na inajaribu ni magumu zaidi.

580
00:44:45,000 --> 00:44:53,000
Si kabisa thamani yake lakini uzoefu wa elimu kama alivyofanya moja.

581
00:44:53,000 --> 00:44:56,000
Jambo la mwisho ni orodha yetu zilizounganishwa,

582
00:44:56,000 --> 00:45:04,000
na mambo haya matatu, mwingi, foleni, na orodha zilizounganishwa,

583
00:45:04,000 --> 00:45:09,000
kitu baadaye wewe milele kufanya katika sayansi ya kompyuta

584
00:45:09,000 --> 00:45:12,000
kudhani una uzoefu na mambo haya.

585
00:45:12,000 --> 00:45:19,000
Wao ni hivyo tu la msingi kwa kila kitu.

586
00:45:19,000 --> 00:45:25,000
>> Wanaohusishwa orodha, na hapa tuna orodha moja moja wanaohusishwa ni kwenda kuwa utekelezaji wetu.

587
00:45:25,000 --> 00:45:34,000
Nini maana ya moja moja wanaohusishwa kinyume na doubly wanaohusishwa? Ndiyo.

588
00:45:34,000 --> 00:45:37,000
[Mwanafunzi] Ni tu anaonyesha pointer ijayo kuliko kuyatumia,

589
00:45:37,000 --> 00:45:39,000
kama moja kabla yake na moja baada yake.

590
00:45:39,000 --> 00:45:44,000
Yeah, hivyo katika format picha, nini mimi tu kufanya?

591
00:45:44,000 --> 00:45:48,000
Nina mambo mawili. Nina picha na picha.

592
00:45:48,000 --> 00:45:51,000
Katika format picha, wanaohusishwa zetu moja moja orodha,

593
00:45:51,000 --> 00:45:57,000
inevitably, tuna baadhi ya aina ya pointer kwa mkuu wa orodha yetu,

594
00:45:57,000 --> 00:46:02,000
na kisha ndani ya orodha yetu, sisi tu kuyatumia,

595
00:46:02,000 --> 00:46:05,000
na labda hii pointi null.

596
00:46:05,000 --> 00:46:08,000
Ni kwenda kuwa kuchora yako mfano wa orodha moja moja wanaohusishwa.

597
00:46:08,000 --> 00:46:14,000
orodha doubly wanaohusishwa, unaweza kwenda nyuma.

598
00:46:14,000 --> 00:46:19,000
Kama mimi kukupa yoyote nodi katika orodha, basi unaweza lazima kupata

599
00:46:19,000 --> 00:46:23,000
yoyote nodi nyingine katika orodha ikiwa ni orodha doubly zinazoungwa.

600
00:46:23,000 --> 00:46:27,000
Lakini kama mimi kupata wewe nodi ya tatu katika orodha na ni orodha moja moja wanaohusishwa,

601
00:46:27,000 --> 00:46:30,000
hakuna njia wewe milele kwenda kupata nodes kwanza na pili.

602
00:46:30,000 --> 00:46:34,000
Na kuna faida na detriments, na moja dhahiri moja

603
00:46:34,000 --> 00:46:42,000
ni wewe kuchukua zaidi ukubwa, na una kuweka wimbo wa ambapo mambo haya ni akizungumzia sasa.

604
00:46:42,000 --> 00:46:49,000
Lakini sisi tu huduma ya juu moja moja wanaohusishwa.

605
00:46:49,000 --> 00:46:53,000
>> mambo machache sisi itawabidi kutekeleza.

606
00:46:53,000 --> 00:47:00,000
Struct yako typedef nodi, int i: struct nodi * ijayo; nodi.

607
00:47:00,000 --> 00:47:09,000
Typedef kwamba lazima kuchomwa ndani ya akili yako.

608
00:47:09,000 --> 00:47:14,000
Quiz 1 lazima kama kutoa typedef ya nodi wanaohusishwa orodha,

609
00:47:14,000 --> 00:47:18,000
na unapaswa kuwa na uwezo wa mara chorochoro kwamba chini

610
00:47:18,000 --> 00:47:22,000
bila hata kufikiria kuhusu hilo.

611
00:47:22,000 --> 00:47:27,000
Mimi nadhani maswali wanandoa, kwa nini tunahitaji struct hapa?

612
00:47:27,000 --> 00:47:32,000
Kwa nini hawawezi sisi kusema * nodi?

613
00:47:32,000 --> 00:47:35,000
[Mwanafunzi] [inaudible]

614
00:47:35,000 --> 00:47:38,000
Yeah.

615
00:47:38,000 --> 00:47:44,000
Kitu tu kwamba amefafanua nodi kama kitu

616
00:47:44,000 --> 00:47:47,000
ni typedef yenyewe.

617
00:47:47,000 --> 00:47:55,000
Lakini kama ya hatua hii, wakati tuko aina ya parsing kupitia ufafanuzi huu nodi struct,

618
00:47:55,000 --> 00:48:01,000
sisi si kumaliza typedef wetu bado, hivyo tangu typedef imekuwa si kumaliza,

619
00:48:01,000 --> 00:48:05,000
nodi haipo.

620
00:48:05,000 --> 00:48:12,000
Lakini struct nodi gani, na hii nodi katika hapa,

621
00:48:12,000 --> 00:48:14,000
hii inaweza pia kuitwa kitu kingine chochote.

622
00:48:14,000 --> 00:48:16,000
Hii inaweza kuitwa n.

623
00:48:16,000 --> 00:48:19,000
Ni inaweza kuitwa zilizounganishwa orodha nodi.

624
00:48:19,000 --> 00:48:21,000
Inaweza kuitwa kitu.

625
00:48:21,000 --> 00:48:26,000
Lakini hii nodi struct anahitaji kuitwa kitu sawa kama nodi hii struct.

626
00:48:26,000 --> 00:48:29,000
Nini wewe piga hii ina pia kuwa hapa,

627
00:48:29,000 --> 00:48:32,000
na hivyo kuwa pia unajibu hatua ya pili ya swali

628
00:48:32,000 --> 00:48:37,000
ambayo ni kwa nini-ya mara nyingi wakati unaweza kuona structs na typedefs ya structs,

629
00:48:37,000 --> 00:48:42,000
utaona structs bila majina ambapo utasikia tu kuona struct typedef,

630
00:48:42,000 --> 00:48:47,000
utekelezaji wa kamusi struct,, au chochote.

631
00:48:47,000 --> 00:48:51,000
>> Kwa nini hapa tunahitaji kusema nodi?

632
00:48:51,000 --> 00:48:54,000
Kwa nini hawawezi kuwa struct bila majina?

633
00:48:54,000 --> 00:48:56,000
Ni karibu jibu sawa.

634
00:48:56,000 --> 00:48:58,000
[Mwanafunzi] Unahitaji rejea ni ndani ya struct.

635
00:48:58,000 --> 00:49:04,000
Yeah, ndani ya struct, unahitaji kwa kutaja struct yenyewe.

636
00:49:04,000 --> 00:49:10,000
Kama wewe si kutoa struct jina, kama ni struct bila majina, huwezi kutaja hayo.

637
00:49:10,000 --> 00:49:17,000
Na mwisho lakini si angalau-haya lazima wote kuwa fulani moja kwa moja,

638
00:49:17,000 --> 00:49:20,000
na wao wanapaswa kukusaidia kutambua kama wewe kuandika hii chini

639
00:49:20,000 --> 00:49:24,000
kuwa wewe ni kufanya kitu kibaya kama hawa aina ya mambo hazina maana.

640
00:49:24,000 --> 00:49:28,000
Mwisho lakini si uchache, kwa nini hii kuwa struct nodi *?

641
00:49:28,000 --> 00:49:34,000
Kwa nini hawawezi tu kuwa struct nodi ijayo?

642
00:49:34,000 --> 00:49:37,000
[Mwanafunzi] Pointer kwa struct ijayo.

643
00:49:37,000 --> 00:49:39,000
Hiyo ni inevitably nini tunataka.

644
00:49:39,000 --> 00:49:42,000
Mbona hakuweza kamwe kuwa struct nodi ijayo?

645
00:49:42,000 --> 00:49:50,000
Kwa nini ni kuwa kwa kuwa struct nodi * ijayo? Yeah.

646
00:49:50,000 --> 00:49:53,000
[Mwanafunzi] Ni kama kitanzi usio.

647
00:49:53,000 --> 00:49:55,000
Yeah.

648
00:49:55,000 --> 00:49:57,000
[Mwanafunzi] Ingekuwa wote kuwa katika moja.

649
00:49:57,000 --> 00:50:02,000
Yeah, nadhani tu wa jinsi tunataka kufanya ukubwa wa au kitu.

650
00:50:02,000 --> 00:50:08,000
Ukubwa wa struct kimsingi ni + au - baadhi mfano hapa au pale.

651
00:50:08,000 --> 00:50:15,000
Ni kimsingi kwenda kuwa jumla ya ukubwa wa mambo katika struct.

652
00:50:15,000 --> 00:50:18,000
Haki hii hapa, bila ya kubadilisha kitu chochote, ukubwa ni kwenda kuwa rahisi.

653
00:50:18,000 --> 00:50:24,000
Ukubwa wa nodi struct ni kwenda kuwa ukubwa wa kawaida i + ya pili.

654
00:50:24,000 --> 00:50:27,000
Ukubwa wa i ni kwenda kuwa 4. Ukubwa wa pili ni kwenda kuwa 4.

655
00:50:27,000 --> 00:50:30,000
Ukubwa wa nodi struct ni kwenda kuwa 8.

656
00:50:30,000 --> 00:50:34,000
Kama hatuna *, kufikiri ya sizeof,

657
00:50:34,000 --> 00:50:37,000
kisha sizeof (i) ni kwenda kuwa 4.

658
00:50:37,000 --> 00:50:43,000
Ukubwa wa nodi struct ijayo itakuwa ni ya kawaida ya i + ukubwa wa nodi ijayo struct

659
00:50:43,000 --> 00:50:46,000
+ Ukubwa wa kawaida i + ya struct nodi ijayo.

660
00:50:46,000 --> 00:50:55,000
Itakuwa recursion usio wa nodi.

661
00:50:55,000 --> 00:51:00,000
Hii ni kwa nini hii ni jinsi mambo kuwa.

662
00:51:00,000 --> 00:51:03,000
>> Tena, dhahiri kukariri kwamba,

663
00:51:03,000 --> 00:51:06,000
au angalau kuelewa kutosha kwamba unaweza kuwa na uwezo wa

664
00:51:06,000 --> 00:51:12,000
sababu kwa nini ni lazima kuangalia kama.

665
00:51:12,000 --> 00:51:14,000
mambo tunakwenda wanataka kutekeleza.

666
00:51:14,000 --> 00:51:18,000
Kama urefu wa orodha-

667
00:51:18,000 --> 00:51:21,000
unaweza kudanganya na kuweka karibu

668
00:51:21,000 --> 00:51:24,000
kimataifa urefu au kitu, lakini sisi siyo kwenda kufanya hiyo.

669
00:51:24,000 --> 00:51:28,000
Sisi ni kwenda kuhesabu urefu wa orodha.

670
00:51:28,000 --> 00:51:34,000
Sisi ina, hivyo ndiyo kimsingi kama kutafuta,

671
00:51:34,000 --> 00:51:41,000
hivyo tuna orodha ya wanaohusishwa integers kuona kama integer hii ni katika orodha zinazoungwa.

672
00:51:41,000 --> 00:51:44,000
Prepend ni kwenda Insert katika mwanzo wa orodha.

673
00:51:44,000 --> 00:51:46,000
Append ni kwenda Insert mwishoni.

674
00:51:46,000 --> 00:51:53,000
Insert_sorted ni kwenda Insert katika nafasi sorted katika orodha.

675
00:51:53,000 --> 00:52:01,000
Insert_sorted aina ya akubali kwamba wewe kamwe kutumika prepend au append katika njia mbaya.

676
00:52:01,000 --> 00:52:09,000
>> Insert_sorted wakati wewe ni kutekeleza insert_sorted-

677
00:52:09,000 --> 00:52:13,000
hebu sema tuna orodha yetu zinazoungwa.

678
00:52:13,000 --> 00:52:18,000
Hii ni nini sasa inaonekana kama, 2, 4, 5.

679
00:52:18,000 --> 00:52:24,000
Nataka Insert 3, hivyo muda mrefu kama orodha yenyewe tayari Iliyopangwa,

680
00:52:24,000 --> 00:52:27,000
ni rahisi kupata ambapo 3 ni mali.

681
00:52:27,000 --> 00:52:29,000
Mimi kuanza saa 2.

682
00:52:29,000 --> 00:52:32,000
Okay, 3, ni mkubwa kuliko 2, hivyo nataka kuendelea.

683
00:52:32,000 --> 00:52:35,000
Oh, 4 ni kubwa mno, hivyo najua 3 yataenda katika kati ya 2 na 4,

684
00:52:35,000 --> 00:52:39,000
na nina kurekebisha kuyatumia na mambo ambayo yote.

685
00:52:39,000 --> 00:52:43,000
Lakini kama sisi hawakuwa madhubuti kutumia insert_sorted,

686
00:52:43,000 --> 00:52:50,000
kama hebu sema tu mimi prepend 6,

687
00:52:50,000 --> 00:52:55,000
kisha orodha yangu zilizounganishwa inaenda kuwa hii.

688
00:52:55,000 --> 00:53:01,000
Ni sasa haina mantiki, hivyo kwa insert_sorted, unaweza kudhani tu

689
00:53:01,000 --> 00:53:04,000
kwamba orodha ni Iliyopangwa, ingawa shughuli zipo

690
00:53:04,000 --> 00:53:09,000
ambayo inaweza kusababisha kwa si sorted, na hiyo ni yake.

691
00:53:09,000 --> 00:53:20,000
Kupata msaada Insert-hivyo hayo ni mambo kuu utaenda kuwa na kutekeleza.

692
00:53:20,000 --> 00:53:24,000
>> Kwa sasa, kuchukua dakika kufanya urefu na ina,

693
00:53:24,000 --> 00:53:30,000
na wale lazima relativt haraka.

694
00:53:41,000 --> 00:53:48,000
Nearing kufunga wakati, hivyo mtu yeyote kuwa na kitu chochote au kwa urefu ina?

695
00:53:48,000 --> 00:53:50,000
Wao wanaenda kuwa karibu kufanana.

696
00:53:50,000 --> 00:53:57,000
[Mwanafunzi] Muda.

697
00:53:57,000 --> 00:54:01,000
Hebu angalia, marekebisho.

698
00:54:01,000 --> 00:54:04,000
Sawa.

699
00:54:12,000 --> 00:54:15,000
Unataka kueleza?

700
00:54:15,000 --> 00:54:21,000
[Mwanafunzi] mimi tu kujenga nodi pointer na initialize kwa kwanza, ambayo ni variable wetu kimataifa,

701
00:54:21,000 --> 00:54:27,000
na kisha mimi kuangalia kuona kama ni null hivyo mimi si kupata kosa seg na kurudi 0 kama kwamba ni kesi.

702
00:54:27,000 --> 00:54:34,000
Vinginevyo, mimi kitanzi kupitia, kuweka wimbo wa ndani integer

703
00:54:34,000 --> 00:54:38,000
mara ngapi nimekuwa accessed kipengele pili ya orodha

704
00:54:38,000 --> 00:54:43,000
na katika operesheni hiyo increment pia kupata kwamba kipengele halisi,

705
00:54:43,000 --> 00:54:47,000
na kisha mimi kuendelea kufanya hundi ya kuona kama ni null,

706
00:54:47,000 --> 00:54:56,000
na kama ni null, basi aborts na anarudi tu idadi ya vipengele nimekuwa kupatikana.

707
00:54:56,000 --> 00:55:01,000
>> [Rob B.] Je, mtu yeyote kuwa na maoni yoyote juu ya kitu chochote?

708
00:55:01,000 --> 00:55:06,000
Hii inaonekana usahihi faini busara.

709
00:55:06,000 --> 00:55:10,000
[Mwanafunzi] sidhani unahitaji nodi == null.

710
00:55:10,000 --> 00:55:13,000
Yeah, hivyo kama nodi == null kurudi 0.

711
00:55:13,000 --> 00:55:18,000
Lakini kama nodi == null basi hii-oh, kuna suala usahihi.

712
00:55:18,000 --> 00:55:23,000
Ni mara tu wewe ni kurudi i, lakini siyo katika wigo hivi sasa.

713
00:55:23,000 --> 00:55:30,000
Wewe tu haja int i, hivyo i = 0.

714
00:55:30,000 --> 00:55:34,000
Lakini kama nodi ni null, basi i bado itakuwa 0,

715
00:55:34,000 --> 00:55:39,000
na sisi ni kwenda na kurudi 0, hivyo kesi hii ni kufanana.

716
00:55:39,000 --> 00:55:48,000
Jambo jingine ni ya kawaida kwa kuweka tangazo

717
00:55:48,000 --> 00:55:51,000
ya nodi ndani ya kwa kitanzi.

718
00:55:51,000 --> 00:55:54,000
Unaweza kusema-oh, hakuna.

719
00:55:54,000 --> 00:55:56,000
Hebu kuitunza kama hii.

720
00:55:56,000 --> 00:55:59,000
Mimi pengine ingekuwa kuweka int i = 0 hapa,

721
00:55:59,000 --> 00:56:05,000
kisha nodi * nodi = kwanza katika hapa.

722
00:56:05,000 --> 00:56:11,000
Na hii pengine ni jinsi-ya kuepuka kupata hii sasa.

723
00:56:11,000 --> 00:56:14,000
Hii pengine ni jinsi mimi ingekuwa imeandikwa yake.

724
00:56:14,000 --> 00:56:21,000
Unaweza pia-kuangalia ni kama hii.

725
00:56:21,000 --> 00:56:25,000
Hii kwa muundo kitanzi haki hapa

726
00:56:25,000 --> 00:56:30,000
wanapaswa kuwa karibu kama asili na wewe kama kwa int i = 0

727
00:56:30,000 --> 00:56:33,000
i ni chini ya urefu wa safu i + +.

728
00:56:33,000 --> 00:56:38,000
Kama kwamba ni jinsi gani wewe iterate juu ya safu, hii ni jinsi gani iterate juu ya orodha zinazoungwa.

729
00:56:38,000 --> 00:56:45,000
>> Hii inapaswa kuwa asili ya pili wakati fulani.

730
00:56:45,000 --> 00:56:50,000
Kwa kuwa katika akili, hii ni kwenda kuwa karibu kitu kimoja.

731
00:56:50,000 --> 00:56:57,000
Utaenda kutaka iterate juu ya orodha zilizounganishwa.

732
00:56:57,000 --> 00:57:02,000
Kama nodi-mimi sielewi nini thamani inaitwa.

733
00:57:02,000 --> 00:57:04,000
Node i.

734
00:57:04,000 --> 00:57:15,000
Kama thamani kwenye nodi kwamba = i kurudi kweli, na hiyo ni yake.

735
00:57:15,000 --> 00:57:18,000
Ona kwamba njia pekee ya sisi milele kurudi uongo

736
00:57:18,000 --> 00:57:23,000
ni kama sisi iterate juu ya orodha nzima wanaohusishwa na kamwe kurudi kweli,

737
00:57:23,000 --> 00:57:29,000
hivyo kwamba ni nini hii gani.

738
00:57:29,000 --> 00:57:36,000
Kama upande note-sisi pengine si kupata append au prepend.

739
00:57:36,000 --> 00:57:39,000
>> Quick mwisho note.

740
00:57:39,000 --> 00:57:52,000
Kama unaweza kuona Keyword tuli, hivyo hebu kusema tuli int kuhesabu = 0,

741
00:57:52,000 --> 00:57:56,000
kisha sisi kufanya kuhesabu + +, unaweza kimsingi kufikiria kama variable kimataifa,

742
00:57:56,000 --> 00:58:00,000
hata mimi tu alisema hii si jinsi sisi ni kwenda kutekeleza urefu.

743
00:58:00,000 --> 00:58:06,000
Mimi nina kufanya hii hapa, na kisha kuhesabu + +.

744
00:58:06,000 --> 00:58:11,000
Njia yoyote tunaweza kuingia ndani ya nodi orodha yetu zilizounganishwa sisi ni incrementing kuhesabu yetu.

745
00:58:11,000 --> 00:58:15,000
hatua ya hii ni nini maana ya Keyword tuli.

746
00:58:15,000 --> 00:58:20,000
Kama mimi tu alikuwa kuhesabu int = 0 kwamba itakuwa mara kwa mara zamani wa kimataifa kutofautiana.

747
00:58:20,000 --> 00:58:25,000
Nini tuli int kuhesabu njia ni kwamba ni variable kimataifa kwa ajili ya faili hii.

748
00:58:25,000 --> 00:58:28,000
Ni vigumu kwa baadhi ya faili nyingine,

749
00:58:28,000 --> 00:58:34,000
kama kufikiria pset 5, kama wewe kuanza.

750
00:58:34,000 --> 00:58:39,000
Kuwa wote speller.c, na una dictionary.c,

751
00:58:39,000 --> 00:58:42,000
na kama wewe tu kutangaza kitu kimataifa, basi chochote katika speller.c

752
00:58:42,000 --> 00:58:45,000
kulipata katika dictionary.c na kinyume chake.

753
00:58:45,000 --> 00:58:48,000
Vigezo Global ni kupatikana kwa faili yoyote c.,

754
00:58:48,000 --> 00:58:54,000
lakini vigezo tuli kupatikana tu kutoka ndani ya faili yenyewe,

755
00:58:54,000 --> 00:59:01,000
hivyo ndani ya Spell kusahihisha au ndani ya dictionary.c,

756
00:59:01,000 --> 00:59:06,000
hii ni aina ya jinsi napenda kutangaza variable yangu kwa ukubwa wa safu yangu

757
00:59:06,000 --> 00:59:10,000
au ukubwa wa namba yangu ya maneno katika kamusi.

758
00:59:10,000 --> 00:59:15,000
Tangu Sitaki kutangaza variable kimataifa kwamba yupo mtu kupata,

759
00:59:15,000 --> 00:59:18,000
Mimi kwa kweli tu huduma ya juu ni kwa makusudi yangu mwenyewe.

760
00:59:18,000 --> 00:59:21,000
>> Jambo nzuri kuhusu hili ni pia jina zima mgongano stuff.

761
00:59:21,000 --> 00:59:27,000
Kama baadhi ya faili nyingine anajaribu kutumia variable kimataifa aitwaye kuhesabu, mambo kwenda sana, vibaya sana,

762
00:59:27,000 --> 00:59:33,000
hivyo hii nicely anaendelea mambo salama, na tu unaweza kupata hiyo,

763
00:59:33,000 --> 00:59:38,000
na hakuna mtu mwingine anaweza, na kama mtu mwingine anatangaza variable kimataifa aitwaye kuhesabu,

764
00:59:38,000 --> 00:59:43,000
basi itakuwa si kuingilia kati na variable yako tuli kuitwa kuhesabu.

765
00:59:43,000 --> 00:59:47,000
Hiyo ni nini tuli ni. Ni faili kimataifa kutofautiana.

766
00:59:47,000 --> 00:59:52,000
>> Maswali juu ya kitu chochote?

767
00:59:52,000 --> 00:59:59,000
Kuweka wote. Bye.

768
00:59:59,000 --> 01:00:03,000
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