1 00:00:00,000 --> 00:00:05,530 2 00:00:05,530 --> 00:00:09,790 >> PROFESA: Kwa hiyo ajenda kwa wiki hii, si mambo ambayo mengi. 3 00:00:09,790 --> 00:00:12,801 Lakini pengine sana, inasaidia sana na muhimu kwa nyie wiki hii. 4 00:00:12,801 --> 00:00:15,550 Lakini tunakwenda kutumia labda 15, Dakika 20 tu kwa haraka kuzungumza 5 00:00:15,550 --> 00:00:17,370 kuhusu orodha kiungo. 6 00:00:17,370 --> 00:00:19,694 Orodha kiungo ni kwenda kufunikwa juu ya jaribio. 7 00:00:19,694 --> 00:00:22,610 Hivyo labda itakuwa msaada sana kujifunza kidogo kuhusu nini kwamba ni. 8 00:00:22,610 --> 00:00:25,210 >> Tunakwenda kutumia kubwa Wengi wa kifungu cha leo 9 00:00:25,210 --> 00:00:27,640 kwenda juu Jaribio sifuri matatizo mazoezi. 10 00:00:27,640 --> 00:00:30,970 Na kisha tutaweza kuokoa labda 20, dakika 30 mwishoni kwa maswali yoyote kuenea 11 00:00:30,970 --> 00:00:32,850 mtu ana. 12 00:00:32,850 --> 00:00:34,610 >> Na kisha, mwisho dakika tano, mimi nina kwenda 13 00:00:34,610 --> 00:00:36,467 kutoa pampu up hotuba kwa jaribio. 14 00:00:36,467 --> 00:00:38,050 Nyie wote wanataka kuwa hapa kwa ajili hiyo. 15 00:00:38,050 --> 00:00:39,591 Kwa sababu ni kwenda kuwa na muda mzuri. 16 00:00:39,591 --> 00:00:42,650 17 00:00:42,650 --> 00:00:49,230 >> Sawa, hivyo baadhi nyenzo kwenye orodha kiungo. 18 00:00:49,230 --> 00:00:52,620 Jinsi re kawaida muundo ni una kile kinachoitwa nodi, sawa? 19 00:00:52,620 --> 00:00:54,870 Una mambo haya kuitwa nodes, ambayo ni structs. 20 00:00:54,870 --> 00:00:57,360 Nitakwenda juu ya jinsi ya kujenga nodi katika slide ijayo. 21 00:00:57,360 --> 00:01:00,680 Lakini kimsingi wote wanaohusishwa orodha ni ni takwimu ambazo 22 00:01:00,680 --> 00:01:03,340 imekuwa strung pamoja kupitia kuyatumia. 23 00:01:03,340 --> 00:01:09,110 >> Na hivyo faida tuna ya kutumia orodha wanaohusishwa juu, 24 00:01:09,110 --> 00:01:11,280 pengine, kama safu, ni ukweli kwamba katika safu 25 00:01:11,280 --> 00:01:15,000 unahitaji moja contiguous kuzuia wa kumbukumbu zote katika sehemu moja, moja 26 00:01:15,000 --> 00:01:16,870 baada ya mwingine, ili kuwa na uwezo wa kuwa na kwamba. 27 00:01:16,870 --> 00:01:20,200 Wakati orodha wanaohusishwa, ungeweza na vipande random kidogo cha kumbukumbu 28 00:01:20,200 --> 00:01:23,020 duniani kompyuta yako strung pamoja na kuyatumia. 29 00:01:23,020 --> 00:01:26,270 >> Na kwa njia hii wanaweza kupata habari 30 00:01:26,270 --> 00:01:28,610 kuja moja baada ya mengine, baada ya nyingine 31 00:01:28,610 --> 00:01:32,720 bila wanaohitaji tu chunk kubwa ya kumbukumbu katika kompyuta yako mahali fulani. 32 00:01:32,720 --> 00:01:35,910 Na hivyo hii ni moja ya kubwa sababu kwa nini tunatumia orodha kiungo. 33 00:01:35,910 --> 00:01:40,300 >> Pili, ni rahisi sana dynamically resize orodha kiungo kwa sababu katika safu, 34 00:01:40,300 --> 00:01:44,720 wakati kutangaza safu, una baadhi ya thamani kuweka. 35 00:01:44,720 --> 00:01:47,340 Hebu sema mimi alitaka kujenga safu ya 10 integers. 36 00:01:47,340 --> 00:01:49,970 Mimi kuunda safu ya 10 integers, na hiyo ni yake. 37 00:01:49,970 --> 00:01:50,580 Ni 10. 38 00:01:50,580 --> 00:01:52,038 Sijui nini cha kufanya baada ya hapo. 39 00:01:52,038 --> 00:01:53,680 Kama nilitaka kufanya hivyo 11, hawawezi kufanya hivyo. 40 00:01:53,680 --> 00:01:55,710 Kama mimi wanataka kufanya hivyo 9, hawawezi kufanya hivyo. 41 00:01:55,710 --> 00:01:59,910 >> Ambapo katika orodha kiungo, unaweza kuongeza na kufuta na kuingiza popote unataka. 42 00:01:59,910 --> 00:02:04,940 Unaweza dynamically resize yako muundo wa hapa, muundo yako data. 43 00:02:04,940 --> 00:02:08,370 Na kwamba inatupa mengi zaidi aliongeza kubadilika 44 00:02:08,370 --> 00:02:11,320 kwamba hatuna kawaida kuwa na arrays. 45 00:02:11,320 --> 00:02:15,210 >> Mtu yeyote kuchanganyikiwa juu ya msingi muundo wa jinsi orodha kiungo ni 46 00:02:15,210 --> 00:02:17,930 au kwa nini tuna kutumia moja juu ya safu? 47 00:02:17,930 --> 00:02:20,330 Naam, tutaweza kwenda juu kwa undani jinsi ya kweli kujenga moja. 48 00:02:20,330 --> 00:02:24,121 Lakini hii ni aina tu ya maana ya jumla ya hivi sasa. 49 00:02:24,121 --> 00:02:24,620 Baridi. 50 00:02:24,620 --> 00:02:28,770 Na hivyo arrays ni strung pamoja wa haya mambo lovely kidogo 51 00:02:28,770 --> 00:02:29,960 aitwaye nodes. 52 00:02:29,960 --> 00:02:32,210 Nodi yote ni aina ya struct. 53 00:02:32,210 --> 00:02:36,090 Kumbuka, struct ni kama alitaka kujenga aina fulani ya kutofautiana 54 00:02:36,090 --> 00:02:39,850 katika C kwamba hana tayari zipo, wewe, kama programu, 55 00:02:39,850 --> 00:02:42,030 kweli anaweza kujenga kwamba wewe mwenyewe. 56 00:02:42,030 --> 00:02:46,540 >> Na hivyo aina hii ya data muundo inaitwa nodi, 57 00:02:46,540 --> 00:02:50,770 ana kweli imekuwa kuundwa kwa yetu, ili haipo ndani ya C juu yake mwenyewe. 58 00:02:50,770 --> 00:02:53,150 Na kwa njia hiyo wewe kujenga moja ni una 59 00:02:53,150 --> 00:02:57,170 kichwa cha typedef struct, ambayo anaelezea compiler mimi nina 60 00:02:57,170 --> 00:02:59,640 kuhusu kujenga struct. 61 00:02:59,640 --> 00:03:00,830 >> Tunakwenda jina hilo "nodi." 62 00:03:00,830 --> 00:03:03,350 Na ndani ya tunakwenda kutangaza kutofautiana katika, 63 00:03:03,350 --> 00:03:05,060 ambayo ni kwenda kuhifadhi thamani. 64 00:03:05,060 --> 00:03:09,320 Na kisha sisi ni pia kwenda kuwa pointer kuitwa "pili" 65 00:03:09,320 --> 00:03:12,090 kwamba pointi kwa ijayo nodi katika orodha ya kiungo. 66 00:03:12,090 --> 00:03:14,730 Na kisha kumaliza kwamba mbali na kurudia tu nodi tena hivyo 67 00:03:14,730 --> 00:03:17,490 compiler anajua, sawa hiyo ni mwisho wa struct yangu. 68 00:03:17,490 --> 00:03:22,540 >> Na hivyo kwa njia hii, tuko aina ya kujenga cute kidogo safu 69 00:03:22,540 --> 00:03:25,450 aina ya kitu kwa thamani na kwa pointer. 70 00:03:25,450 --> 00:03:27,757 Na unaweza kuhusisha watu wote pamoja na kuyatumia hizo. 71 00:03:27,757 --> 00:03:30,090 Ili waweze kuwa na kila aina strung pamoja katika mlolongo. 72 00:03:30,090 --> 00:03:32,920 73 00:03:32,920 --> 00:03:34,162 >> Baridi. 74 00:03:34,162 --> 00:03:35,453 Je, unaweza kusikia kwamba kidogo bora? 75 00:03:35,453 --> 00:03:36,140 >> Watazamaji: Naam. 76 00:03:36,140 --> 00:03:38,540 >> PROFESA: zote haki. 77 00:03:38,540 --> 00:03:44,280 Hivyo njia hiyo, kama wewe guys unaweza kuona, kawaida kiungo orodha ni muundo 78 00:03:44,280 --> 00:03:45,500 ni una kichwa. 79 00:03:45,500 --> 00:03:49,460 Una thamani kichwa ambayo si kuwa alisema na pointer mwingine yeyote. 80 00:03:49,460 --> 00:03:53,177 Lakini itakuja kumweka katika, au rejea, nodi mwingine. 81 00:03:53,177 --> 00:03:56,510 Nodi baada anaenda rejea nodi baada ya hapo, na kadhalika na kadhalika 82 00:03:56,510 --> 00:03:59,170 mpaka hatimaye kugonga Mwisho wa kiungo orodha yako. 83 00:03:59,170 --> 00:04:00,980 Na wewe tu wala kuwa pointer huko. 84 00:04:00,980 --> 00:04:04,659 >> Na hivyo, nadhani kama, juu ya mlolongo, au hata kama mmoja wenu guys alifanya, mimi sijui, 85 00:04:04,659 --> 00:04:06,450 kama na matunda Loops ulipokuwa mdogo. 86 00:04:06,450 --> 00:04:08,590 Wewe ungekuwa kamba yao pamoja na kuvaa kwao shingoni yako. 87 00:04:08,590 --> 00:04:09,840 Nadhani ni halisi kitu kimoja. 88 00:04:09,840 --> 00:04:12,964 Una mambo haya kidogo kwamba Unaweza kamba pamoja kwamba hatua kwa moja 89 00:04:12,964 --> 00:04:15,291 baada ya hayo, ili moja baada ya yake, na kadhalika na kadhalika 90 00:04:15,291 --> 00:04:17,040 mpaka una mlolongo muundo wa data 91 00:04:17,040 --> 00:04:21,190 kwamba unaweza kutumia hata hivyo wewe kama. 92 00:04:21,190 --> 00:04:27,370 >> Hivyo njia kwamba hii tunataka kawaida kuingiza au kufuta 93 00:04:27,370 --> 00:04:30,020 node yoyote kutoka kwa kiungo orodha ni tofauti sana 94 00:04:30,020 --> 00:04:31,970 kulingana na pale kwamba nodi ni. 95 00:04:31,970 --> 00:04:34,880 Hivyo, kwa mfano, kwa sababu kuyatumia ni daima 96 00:04:34,880 --> 00:04:38,645 akionyesha thamani maalum, wakati kufuta au kuingiza nodi, 97 00:04:38,645 --> 00:04:41,770 unataka kuhakikisha kwamba pointer yote ni akionyesha mambo ya haki. 98 00:04:41,770 --> 00:04:46,200 >> Hivyo kama alitaka uwezekano wa kuingiza nodi mpya kwa thamani ya moja 99 00:04:46,200 --> 00:04:48,379 ndani ya kiungo yamepangwa orodha, sisi wote tunajua hapa 100 00:04:48,379 --> 00:04:51,170 kutoka picha kwamba itakuja kwenda katika kati ya kichwa na mbili, sawa? 101 00:04:51,170 --> 00:04:52,620 Kwa sababu moja inafaa haki pale. 102 00:04:52,620 --> 00:04:59,060 Lakini njia ambayo tunataka kufanya kwamba ni na dereferencing pointer 103 00:04:59,060 --> 00:05:02,160 kutoka kichwa na kutuma kwamba kwa moja. 104 00:05:02,160 --> 00:05:05,040 >> Lakini sisi kuja katika tatizo hapa. 105 00:05:05,040 --> 00:05:08,280 Je, mtu yeyote kuona nini tatizo ni kama tulikuwa dereference kwanza 106 00:05:08,280 --> 00:05:10,090 pointer kutoka kichwa na moja? 107 00:05:10,090 --> 00:05:14,202 Nini tatizo gani sisi kukimbia katika kama sisi kujaribu kuongeza hii mbele ya safu yetu? 108 00:05:14,202 --> 00:05:15,409 >> Watazamaji: [inaudible] 109 00:05:15,409 --> 00:05:16,200 PROFESA: Hasa. 110 00:05:16,200 --> 00:05:20,000 Hivyo hapa tuna pointer kwamba alikuwa mara moja akizungumzia kutoka kichwa na mbili. 111 00:05:20,000 --> 00:05:23,120 Lakini kama wewe kujikwamua kwamba pointer, wewe kumweka kwa moja, 112 00:05:23,120 --> 00:05:26,500 sisi sasa kuwa na wazo wapi pa kwenda kupata mbili. 113 00:05:26,500 --> 00:05:29,850 Kwa sababu kama nilivyosema hapo kabla, nimepata kubwa chunk ya kumbukumbu katika kompyuta yako. 114 00:05:29,850 --> 00:05:31,860 Nodes haya yote naweza nasibu Kukifuatiwa 115 00:05:31,860 --> 00:05:33,350 katika sehemu yoyote katika kompyuta yako. 116 00:05:33,350 --> 00:05:36,140 Na wewe hawajui jinsi kwenda juu ya kutafuta hiyo. 117 00:05:36,140 --> 00:05:40,420 >> Na hivyo unahitaji kuwa na kuyatumia akizungumzia nodes wote mwishoni. 118 00:05:40,420 --> 00:05:42,420 Au mwingine kama ajali dereference moja 119 00:05:42,420 --> 00:05:44,485 bila kumshirikisha kwanza thamani kwanza, uko 120 00:05:44,485 --> 00:05:47,410 tu kwenda kupoteza kila kitu baadaye. 121 00:05:47,410 --> 00:05:49,720 >> Kwa hiyo kile tunakwenda kufanya ni, wewe ungekuwa kwanza 122 00:05:49,720 --> 00:05:53,270 unataka kujenga pointer juu ya nodi unataka kuingiza. 123 00:05:53,270 --> 00:05:55,270 Kumweka ambapo wewe wanataka kuingiza kwa, 124 00:05:55,270 --> 00:05:59,410 na kisha baadaye wewe inaweza kumweka kichwa nyuma moja. 125 00:05:59,410 --> 00:06:02,800 >> Je, hiyo mantiki kwa kila mtu hapa? 126 00:06:02,800 --> 00:06:03,346 Kubwa. 127 00:06:03,346 --> 00:06:04,720 Fikiria kama tu kama mlolongo. 128 00:06:04,720 --> 00:06:07,420 Ikiwa kuongeza mlolongo, ni aina ya Intuitive 129 00:06:07,420 --> 00:06:10,742 jinsi wewe d kwenda juu ya kuingiza hilo. 130 00:06:10,742 --> 00:06:15,274 >> OK, hivyo kwamba ni kweli sana mfupi kuliko mimi walidhani itakuwa, 131 00:06:15,274 --> 00:06:16,690 dakika tano sapa katika orodha ya kiungo. 132 00:06:16,690 --> 00:06:19,960 Hivyo tu nyie na wazo msingi wa kile ambacho ni. 133 00:06:19,960 --> 00:06:23,580 >> Hapa tuna ajenda kwa jaribio sifuri. 134 00:06:23,580 --> 00:06:24,895 Je, si lazima hii kuwatisha ninyi. 135 00:06:24,895 --> 00:06:26,270 Najua ni mengi ya habari. 136 00:06:26,270 --> 00:06:27,580 Inaonekana sana inatisha. 137 00:06:27,580 --> 00:06:33,130 Ni pia mengi ya, mimi kufikiri, CSC aina ya masharti. 138 00:06:33,130 --> 00:06:37,440 Mambo kama masharti hexadecimal, kuyatumia, mgao wa kumbukumbu ya nguvu 139 00:06:37,440 --> 00:06:40,120 ni suala sana inatisha sounding. 140 00:06:40,120 --> 00:06:42,700 >> Lakini tunakwenda kuvunja yao chini, kufanya baadhi ya matatizo mazoezi 141 00:06:42,700 --> 00:06:44,980 ili nyie wote ni tayari kwa mtihani huu. 142 00:06:44,980 --> 00:06:47,104 Ni wangapi wenu guys kuwa tayari kuanza kusoma? 143 00:06:47,104 --> 00:06:50,040 144 00:06:50,040 --> 00:06:53,670 >> OK, nyie pengine wanataka kuanza kupata kuanza 145 00:06:53,670 --> 00:06:56,480 juu ya kwamba, kwa sababu ya jaribio ni kesho. 146 00:06:56,480 --> 00:06:58,739 Au Alhamisi kwa baadhi yenu. 147 00:06:58,739 --> 00:07:01,030 Yeah, hivyo sisi ni kwenda juu ya baadhi ya matatizo mazoezi. 148 00:07:01,030 --> 00:07:04,600 Kama nyie wote wanataka kuchukua nje ya karatasi, kalamu. 149 00:07:04,600 --> 00:07:07,310 Tunakwenda kutumia tu idadi kubwa ya kifungu cha leo 150 00:07:07,310 --> 00:07:11,590 kwenda juu baadhi ya kwamba hivyo nyie na wazo la nini cha kutarajia juu ya jaribio. 151 00:07:11,590 --> 00:07:14,957 152 00:07:14,957 --> 00:07:16,890 >> SAWA. 153 00:07:16,890 --> 00:07:19,730 Michache ya vifaa maelezo pia, kwa mtu yeyote 154 00:07:19,730 --> 00:07:25,120 ambao haijawahi kwa kiungo kwamba kuna, kama kwenda cs50.yale.edu, juu ya mbele 155 00:07:25,120 --> 00:07:28,566 ukurasa huu kuna uhusiano kwamba anasema "Kuhusu Quiz sifuri." 156 00:07:28,566 --> 00:07:29,440 Kiungo inachukua wewe huko. 157 00:07:29,440 --> 00:07:31,065 Kama si kusoma, tafadhali kusoma. 158 00:07:31,065 --> 00:07:34,470 Kwa sababu atakwambia kweli ni muhimu habari kuhusu jaribio. 159 00:07:34,470 --> 00:07:37,410 >> Mimi nina kwenda kuvuta hii nje kutoka kwamba kwa sababu tu, kimwili, 160 00:07:37,410 --> 00:07:40,200 kama nyie sijui wapi kwenda, tutakuwa na matatizo. 161 00:07:40,200 --> 00:07:44,220 Na hivyo kama jana wako katika suala kwa A kwa N, kwenda ukumbi sheria shule. 162 00:07:44,220 --> 00:07:47,500 Na kama kuanza yako ya mwisho na P A to Z, kwenda Davies Ukumbi wa. 163 00:07:47,500 --> 00:07:50,240 Na hii inatumika tu kwa Watu katika sehemu ya Jumatano. 164 00:07:50,240 --> 00:07:53,420 >> Kama wewe ni kuchukua jaribio kwenye Alhamisi, wewe kwenda SSS 114 165 00:07:53,420 --> 00:07:55,078 ambapo hotuba yako kawaida ni. 166 00:07:55,078 --> 00:07:55,953 Watazamaji: [inaudible] 167 00:07:55,953 --> 00:07:59,316 168 00:07:59,316 --> 00:08:01,940 PROFESA: O to Z, wewe ni kwenda kwenda Davies ukumbi. 169 00:08:01,940 --> 00:08:03,273 Mimi nina kwenda kubadili hali hiyo, haki? 170 00:08:03,273 --> 00:08:05,670 171 00:08:05,670 --> 00:08:09,698 >> Oh, yeah, wewe tu kushindwa moja kwa moja. 172 00:08:09,698 --> 00:08:11,753 >> Oh yeah, hiyo ni wewe Christa. 173 00:08:11,753 --> 00:08:15,190 174 00:08:15,190 --> 00:08:16,030 Naam, mbaya wangu. 175 00:08:16,030 --> 00:08:17,610 Yep, O to Z, wewe ni kwenda kwenda Davies Auditorim. 176 00:08:17,610 --> 00:08:19,140 Mimi nina kwenda kurekebisha hili mara moja mimi kupakia. 177 00:08:19,140 --> 00:08:20,320 Naam. 178 00:08:20,320 --> 00:08:22,160 >> Na kisha pia kitu muhimu kwa akili 179 00:08:22,160 --> 00:08:25,290 ni kwamba Jumatano, ikiwa ni rasmi waliojiunga na kifungu cha Jumatano, 180 00:08:25,290 --> 00:08:26,832 lazima kuchukua jaribio yako siku ya Jumatano. 181 00:08:26,832 --> 00:08:29,706 Na kama wewe ni waliojiunga na Alhamisi, lazima kuchukua jaribio yako Alhamisi. 182 00:08:29,706 --> 00:08:31,000 Na ni wakati darasani. 183 00:08:31,000 --> 00:08:35,970 Ambapo, nadhani ni kama 1:00 kwa 02:15 juu ya Jumatano na 2:30-03:45 184 00:08:35,970 --> 00:08:37,220 Alhamisi. 185 00:08:37,220 --> 00:08:41,710 >> Kama una migogoro irreconcilable, Visingizio Dean wa ni kitu pekee, 186 00:08:41,710 --> 00:08:43,030 kwa bahati mbaya, tunaweza kuchukua. 187 00:08:43,030 --> 00:08:45,560 Kwa sababu tumekuwa na idadi kubwa ya maombi 188 00:08:45,560 --> 00:08:47,970 kubadili kutoka Jumatano Alhamisi. 189 00:08:47,970 --> 00:08:51,265 Ambayo hatuwezi kutimiza isipokuwa tuna ombi Dean wa. 190 00:08:51,265 --> 00:08:52,650 >> SAWA. 191 00:08:52,650 --> 00:08:57,000 Hivyo kabla ya sisi kupata kuanza juu ya michache ya matatizo mazoezi, 192 00:08:57,000 --> 00:09:00,540 Mimi tu kwenda juu Andy tips msaada kwa ajili ya mafanikio. 193 00:09:00,540 --> 00:09:04,140 Nyie, wakati wewe kujifunza, kwa kweli wanataka kufanya mazoezi ya kuandika kificho kwa mkono. 194 00:09:04,140 --> 00:09:07,050 Mara ya kwanza mimi milele alichukua Jaribio CS, nilikuwa na si 195 00:09:07,050 --> 00:09:09,960 kuandika mazoezi kificho kwa mkono kabla na ilikuwa kubwa mno 196 00:09:09,960 --> 00:09:11,890 kushangaza jinsi ilivyokuwa vigumu. 197 00:09:11,890 --> 00:09:16,125 >> Wakati nyie si kupata katika tabia ya kuandika nje kila kitu, 198 00:09:16,125 --> 00:09:20,260 inakuja sana kawaida kuwa uwezo wa kuwa autocompleted 199 00:09:20,260 --> 00:09:22,015 mabano na semicolons huko. 200 00:09:22,015 --> 00:09:23,890 Wakati kuandika ni nje kwa mkono, wakati mwingine ni 201 00:09:23,890 --> 00:09:27,100 sana, ni rahisi sana kusahau semicolon, au kusahau kwa karibu mabano, 202 00:09:27,100 --> 00:09:30,970 au kusahau kwa karibu matumbo, au kitu kama hicho. 203 00:09:30,970 --> 00:09:34,322 >> Hivyo wakati wewe kuandika kanuni kwa mkono, ni kujisikia tofauti sana. 204 00:09:34,322 --> 00:09:37,280 Hivyo nyie, wakati wewe ni kazi kupitia baadhi ya matatizo mazoezi, 205 00:09:37,280 --> 00:09:38,904 ingekuwa nzuri kwa kweli mazoezi leo. 206 00:09:38,904 --> 00:09:41,770 Au kesho, nadhani, kama wewe ni kuchukua chemsha bongo siku ya Alhamisi. 207 00:09:41,770 --> 00:09:45,280 >> Pili, tuna iliyopita, kama, thamani nane mwaka wa mazoezi 208 00:09:45,280 --> 00:09:47,070 Quizzes online. 209 00:09:47,070 --> 00:09:50,759 Jaribio la mwaka huu pengine kuwa sana, ni sawa na wote. 210 00:09:50,759 --> 00:09:51,800 Wao ni wote ni sawa. 211 00:09:51,800 --> 00:09:54,220 Aina ya kupata katika mtindo wa aina ya maswali 212 00:09:54,220 --> 00:09:57,250 tuyaombayo, aina ya kazi ambayo tutaweza kuandika katika, 213 00:09:57,250 --> 00:09:58,580 nakadhalika, nakadhalika. 214 00:09:58,580 --> 00:10:01,980 >> Hivyo kuchukua Quizzes mazoezi, hasa chini ya vikwazo wakati. 215 00:10:01,980 --> 00:10:05,390 Dakika 75 kufanya jaribio ni si mengi ya kiasi cha muda. 216 00:10:05,390 --> 00:10:07,254 Ni sana, mrefu sana. 217 00:10:07,254 --> 00:10:09,670 Na hivyo nyie kweli wanataka kuhakikisha kwamba nyie ni 218 00:10:09,670 --> 00:10:11,990 katika tabia ya kuandika kificho kwa mkono haraka. 219 00:10:11,990 --> 00:10:15,070 Kwa sababu wewe hawataki kwanza muda wa kuona jaribio la kuwa urefu 220 00:10:15,070 --> 00:10:16,560 kuwa juu ya jaribio lako. 221 00:10:16,560 --> 00:10:20,540 Nyie kweli wanataka kuhakikisha kwamba zoezi kabla. 222 00:10:20,540 --> 00:10:24,550 >> Nne, unataka kupitia hotuba na sehemu slides. 223 00:10:24,550 --> 00:10:25,980 Huna kwa kukariri mambo. 224 00:10:25,980 --> 00:10:30,430 Kwa kweli, kila mtu anaruhusiwa karatasi moja ya maelezo ya karatasi nyeupe, 225 00:10:30,430 --> 00:10:31,090 mbele na nyuma. 226 00:10:31,090 --> 00:10:32,920 Nyie unaweza aina au kuandika. 227 00:10:32,920 --> 00:10:37,070 Kama wewe mwenyewe kupata wanaohitaji kukariri kitu chochote, kuiweka chini kwenye karatasi hiyo. 228 00:10:37,070 --> 00:10:40,810 >> Mimi kuhakikisha wewe, hawataki kuwa kukwama katikati ya jaribio kwamba 229 00:10:40,810 --> 00:10:43,890 kuwa kama, oh yeah, nini Runtime wa aina hii dhidi ya aina hiyo. 230 00:10:43,890 --> 00:10:46,490 Tu kuiweka chini na nakala yake moja kwa moja kutoka kumbuka karatasi yako. 231 00:10:46,490 --> 00:10:50,420 Basi unaweza kweli kutumia tu yako ubongo kufikiri juu ya matatizo 232 00:10:50,420 --> 00:10:52,190 badala ya kuwa na kukumbuka ukweli. 233 00:10:52,190 --> 00:10:55,250 Na hivyo kweli kuchukua faida ya maelezo yoyote niche 234 00:10:55,250 --> 00:11:00,140 ambayo unadhani unahitaji kukariri, plop ni chini ya mapitio karatasi. 235 00:11:00,140 --> 00:11:02,680 >> Sawa, maswali yoyote logistically Jaribio kuhusu 236 00:11:02,680 --> 00:11:05,510 kabla ya kuanza baadhi matatizo Jaribio mazoezi? 237 00:11:05,510 --> 00:11:06,416 Yeah? 238 00:11:06,416 --> 00:11:10,040 >> Watazamaji: Mimi si alikuwa na nafasi kuangalia jaribio [inaudible] 239 00:11:10,040 --> 00:11:11,757 lakini je, ni kwenda kuwa maombi zaidi, 240 00:11:11,757 --> 00:11:14,090 au ni kuna pia kwenda kuwa, kama, maswali maarifa? 241 00:11:14,090 --> 00:11:14,940 >> PROFESA: Ni mengi. 242 00:11:14,940 --> 00:11:16,731 Hivyo, kwa njia hiyo mimi ingekuwa ilivyoelezwa Jaribio 243 00:11:16,731 --> 00:11:18,810 is-- mimi kuweka pamoja baadhi ya matatizo mazoezi 244 00:11:18,810 --> 00:11:20,960 kwamba mimi vunjwa kutoka pande zote za Quizzes. 245 00:11:20,960 --> 00:11:25,210 Lakini utaona kwamba kuna kuu mbili aina ya maswali tutakuuliza wewe. 246 00:11:25,210 --> 00:11:28,750 >> Moja ni kiwango cha chini sana undani wa mambo ya ajabu. 247 00:11:28,750 --> 00:11:31,720 Tutaweza kukupa chunk ndogo ya kificho na kusema, je kuna kosa hapa? 248 00:11:31,720 --> 00:11:33,110 Nini itakuwa uchapishaji nje hapa? 249 00:11:33,110 --> 00:11:35,980 Nini kanuni hii kuzalisha, nakadhalika. 250 00:11:35,980 --> 00:11:38,710 Hivyo kiwango cha chini sana habari maelezo. 251 00:11:38,710 --> 00:11:42,700 >> Na upande wa flip, tutaweza kuwa sana kiwango cha juu maswali elimu makao. 252 00:11:42,700 --> 00:11:45,190 Je, unaweza kueleza kile Tofauti kati ya binary tafuta 253 00:11:45,190 --> 00:11:46,148 na tafuta linear ni? 254 00:11:46,148 --> 00:11:48,500 Kwa nini tunataka kutumia moja juu ya nyingine? 255 00:11:48,500 --> 00:11:49,960 Labda, ni nini GDB? 256 00:11:49,960 --> 00:11:51,560 Kwa nini tunataka kutumia GDB? 257 00:11:51,560 --> 00:11:54,590 Ngazi ya juu, zaidi ya msingi uelewa maswali. 258 00:11:54,590 --> 00:11:58,240 Hivyo utaona mchanganyiko wa wawili kati yao juu ya jaribio lako. 259 00:11:58,240 --> 00:12:01,462 >> Kitu kingine chochote kabla ya sisi kichwa moja kwa moja ndani yake? 260 00:12:01,462 --> 00:12:02,879 SAWA. 261 00:12:02,879 --> 00:12:03,670 Watazamaji: Moja zaidi. 262 00:12:03,670 --> 00:12:04,030 PROFESA: Oh, moja zaidi. 263 00:12:04,030 --> 00:12:04,340 Pole. 264 00:12:04,340 --> 00:12:05,631 >> Watazamaji: Yeah, ni sawa. 265 00:12:05,631 --> 00:12:10,140 Hivyo ni kusema dakika 75 ni mfupi mno, kama hakuna uwezekano 266 00:12:10,140 --> 00:12:11,640 kwamba sisi kumaliza? 267 00:12:11,640 --> 00:12:13,571 Au, kama, dakika 75 ni wakati hasa kama kiasi 268 00:12:13,571 --> 00:12:15,700 kama tunataka haja kama tulikuwa ipasavyo tayari? 269 00:12:15,700 --> 00:12:17,450 PROFESA: Sawa, hivyo Jaribio ni changamoto. 270 00:12:17,450 --> 00:12:19,550 Ni dhahiri changamoto. 271 00:12:19,550 --> 00:12:21,092 Utapata mwenyewe short kwa wakati. 272 00:12:21,092 --> 00:12:24,341 Pengine wewe kwenda kuikumba, kama 10, Dakika 15 kwenda, na kuwa kama, shit. 273 00:12:24,341 --> 00:12:25,520 I have sana kufanywa. 274 00:12:25,520 --> 00:12:26,520 Na hiyo ndiyo kabisa faini. 275 00:12:26,520 --> 00:12:28,740 Kila mtu kwenda kuhisi kwa njia hiyo. 276 00:12:28,740 --> 00:12:31,074 >> Tu kuwa makini sana ya muda kiasi gani una. 277 00:12:31,074 --> 00:12:33,490 Na hivyo ndiyo sababu nawaambia guys kufanya Quizzes mazoezi. 278 00:12:33,490 --> 00:12:36,672 Kwa sababu ni kweli anatoa maana kubwa nini jaribio ni kwenda kuwa kama. 279 00:12:36,672 --> 00:12:39,130 Hivyo kama wewe mwenyewe kupata kuwa uwezo wa kumaliza mazoezi 280 00:12:39,130 --> 00:12:41,671 Quizzes katika kiasi nzuri ya muda, unaweza kasi mwenyewe vizuri, 281 00:12:41,671 --> 00:12:45,695 basi si kuwa na tatizo Jumatano au Alhamisi. 282 00:12:45,695 --> 00:12:46,575 >> Baridi. 283 00:12:46,575 --> 00:12:49,200 Hivyo kama kila mtu wants-- Nadhani watu wengi kuwa karatasi 284 00:12:49,200 --> 00:12:49,810 nje tayari. 285 00:12:49,810 --> 00:12:52,604 Mimi nina kwenda kimsingi tu kukupa maswali sampuli, 286 00:12:52,604 --> 00:12:54,520 kukupa guys, kama, a dakika chache kwa kuyafanya. 287 00:12:54,520 --> 00:12:59,610 Na tutaweza kwenda juu kama darasa nini majibu yao ni. 288 00:12:59,610 --> 00:13:02,860 >> Hivyo hii ni ya kawaida sana swali mapema tutaweza 289 00:13:02,860 --> 00:13:06,720 kuuliza wewe, kuwabadili tu nambari kati ya kali tofauti. 290 00:13:06,720 --> 00:13:09,070 Mapacha, kama nyie Unaweza wanakumbuka, ni msingi mbili. 291 00:13:09,070 --> 00:13:12,470 Alisema ni msingi 10, au nini sisi kama binadamu kwa kawaida kutafsiri. 292 00:13:12,470 --> 00:13:17,120 Hexadesimoli ni msingi 16, ambayo ni sifuri kupitia tisa ikiwa ni pamoja na kupitia F. 293 00:13:17,120 --> 00:13:19,990 >> Hivyo kuna namba nne mimi nina kuuliza nyie kubadili hapa. 294 00:13:19,990 --> 00:13:23,909 Mimi nitakupa wewe kama, tatu kwa dakika nne kufikiri kupitia jinsi 295 00:13:23,909 --> 00:13:25,200 tunataka kwenda kuhusu utatuzi huu. 296 00:13:25,200 --> 00:13:32,832 297 00:13:32,832 --> 00:13:35,710 >> Watazamaji: Je, ni halali calculators? 298 00:13:35,710 --> 00:13:37,630 >> PROFESA: Wewe si haja calculators, yeah. 299 00:13:37,630 --> 00:13:42,420 Nadhani Aidha msingi, nadhani, ni nyie wote atatakiwa kufanya. 300 00:13:42,420 --> 00:14:41,700 301 00:14:41,700 --> 00:14:45,070 >> Na hivyo tu mimi aina ya kuwa na hisia ya wakati kila mtu ni kosa, kuangalia juu, 302 00:14:45,070 --> 00:14:47,429 nguvu, sijui, tabasamu, kuangalia na furaha kama wewe ni kosa. 303 00:14:47,429 --> 00:14:47,929 Naam. 304 00:14:47,929 --> 00:17:21,680 305 00:17:21,680 --> 00:17:23,945 Labda wanandoa dakika zaidi. 306 00:17:23,945 --> 00:18:28,080 307 00:18:28,080 --> 00:18:29,600 >> OK, hebu kuleta katika. 308 00:18:29,600 --> 00:18:31,580 Mimi makusudi kwenda kutoa nyie muda kidogo 309 00:18:31,580 --> 00:18:33,760 kuliko pengine haja ya kufanya baadhi ya matatizo haya, 310 00:18:33,760 --> 00:18:37,124 tu kwa sababu nataka kuhakikisha kwamba tunapata kupitia rundo la matatizo. 311 00:18:37,124 --> 00:18:39,290 Hivyo hakuna wasiwasi kama alivyofanya si kuwa na nafasi ya kumaliza. 312 00:18:39,290 --> 00:18:43,770 Kabisa sawa kwa muda mrefu kama una wazo la jinsi ya kwenda kuhusu hili. 313 00:18:43,770 --> 00:18:45,850 Basi hebu kwenda mbele na kufanya moja ya kwanza. 314 00:18:45,850 --> 00:18:52,690 315 00:18:52,690 --> 00:18:57,870 >> Hivyo kwanza, haina mtu yeyote wanataka kuniambia katika mapacha, je kila mmoja tarakimu haya 316 00:18:57,870 --> 00:19:00,484 kuwakilisha katika suala la maadili yao? 317 00:19:00,484 --> 00:19:01,250 Yeah? 318 00:19:01,250 --> 00:19:03,349 >> Watazamaji: Mbili kwa nguvu sifuri, 2-1. 319 00:19:03,349 --> 00:19:04,140 PROFESA: Hasa. 320 00:19:04,140 --> 00:19:04,640 So. 321 00:19:04,640 --> 00:19:13,430 322 00:19:13,430 --> 00:19:16,430 >> Haki, hivyo kawaida wakati tuko katika wigo 10 323 00:19:16,430 --> 00:19:20,580 haya yote ni wa kuwakilisha, kama, 10 ya msingi ya sifuri, sawa? 324 00:19:20,580 --> 00:19:21,810 Hiyo ni sehemu moja yako. 325 00:19:21,810 --> 00:19:24,520 Wote wako mahali 10 ni ni 10 kwa nguvu za yule. 326 00:19:24,520 --> 00:19:26,600 Wewe 100 mahali ni 10 kwa nguvu ya mbili. 327 00:19:26,600 --> 00:19:29,570 >> Chochote msingi uko katika kinaenda cha kufanya na halisi kitu kimoja, 328 00:19:29,570 --> 00:19:31,480 tu na msingi tofauti. 329 00:19:31,480 --> 00:19:34,130 Hivyo binary, kila kitu kilicho ni msingi mbili. 330 00:19:34,130 --> 00:19:37,110 Wewe ni kwenda kubadilisha wote tarakimu katika mbili kwa nguvu chochote 331 00:19:37,110 --> 00:19:38,190 ya kwamba tarakimu. 332 00:19:38,190 --> 00:19:41,450 Na hivyo kwa maana hii, sisi unaweza kuwa njia rahisi 333 00:19:41,450 --> 00:19:43,800 ya kuweza kuongeza hadi au kuhitimisha namba zote ili 334 00:19:43,800 --> 00:19:46,010 kubadili ndani ya wigo 10. 335 00:19:46,010 --> 00:19:50,362 >> Hivyo haina mtu yeyote wanataka kuniambia nini jibu la moja kwanza ni katika wigo wa kumi? 336 00:19:50,362 --> 00:19:51,674 >> Watazamaji: Mbili, [inaudible] 337 00:19:51,674 --> 00:19:52,340 PROFESA: Naam. 338 00:19:52,340 --> 00:19:53,230 Watazamaji: 42. 339 00:19:53,230 --> 00:19:56,560 PROFESA: 42, kuna kwenda. 340 00:19:56,560 --> 00:20:00,660 Hivyo njia tulipata jibu hili lilikuwa na kufanya mbili za kwanza, hizo ni mbili. 341 00:20:00,660 --> 00:20:02,760 Plus mbili ya tatu, ambayo ni nane. 342 00:20:02,760 --> 00:20:07,590 Plus mbili kwa tano, ambayo ni chochote ni kushoto juu. 343 00:20:07,590 --> 00:20:09,390 Wewe kuhitimisha yao juu na ni 42. 344 00:20:09,390 --> 00:20:12,000 >> Ni mtu yeyote kuchanganyikiwa juu ya jinsi sisi got kwamba? 345 00:20:12,000 --> 00:20:15,630 Aidha hivyo msingi, kama Nilisema, unapaswa kuwa sawa. 346 00:20:15,630 --> 00:20:17,410 Kama siyo, vizuri, tunaweza kufanya mazoezi kwamba pia. 347 00:20:17,410 --> 00:20:18,720 Lakini hiyo ni sawa. 348 00:20:18,720 --> 00:20:20,560 Baridi. 349 00:20:20,560 --> 00:20:25,570 >> Je, mtu yeyote wanataka kunipa kujibu kwa moja pili vile vile? 350 00:20:25,570 --> 00:20:26,860 >> 50? 351 00:20:26,860 --> 00:20:27,600 Nzuri. 352 00:20:27,600 --> 00:20:30,044 Mtu yeyote kuchanganyikiwa juu ya jinsi tulipata kuwa ama? 353 00:20:30,044 --> 00:20:31,960 Baridi, mimi itabidi majibu juu ya slide ijayo. 354 00:20:31,960 --> 00:20:34,440 Hivyo hakuna wasiwasi kama wewe haja ya nakala yake chini. 355 00:20:34,440 --> 00:20:38,860 >> OK, hivyo hexadecimal ni kidogo trickier. 356 00:20:38,860 --> 00:20:41,840 lakini mimi nina kwenda kuonyesha nyie njia ya mkato kwa jinsi ya kufanya hivyo. 357 00:20:41,840 --> 00:20:44,800 Hivyo hexadecimal, kama wewe kumbuka, yote ni kuwa 16. 358 00:20:44,800 --> 00:20:48,920 Na kwa sababu sisi kama binadamu si kweli kuwa na idadi 16 kuiwakilisha kwamba, 359 00:20:48,920 --> 00:20:56,940 sisi kwenda kutoka sifuri hadi tisa, ambayo yetu ya kwanza Maadili ya 10, na kisha sisi kufanya kupitia F, 360 00:20:56,940 --> 00:20:58,630 ambayo ni karibu maadili sita. 361 00:20:58,630 --> 00:21:03,040 >> Na hivyo njia rahisi ya kwenda kutoka idadi yoyote mapacha kwa hexadesimoli 362 00:21:03,040 --> 00:21:05,350 ni kuvunja yao juu katika nusu. 363 00:21:05,350 --> 00:21:10,042 Na hivyo idadi yoyote binary tutaweza kutoa unaweza kuwa na tarakimu nane. 364 00:21:10,042 --> 00:21:11,750 Unaweza tu kuvunja yao juu katikati. 365 00:21:11,750 --> 00:21:17,460 >> Hivyo kwanza one-- moja moja, moja moja, moja, moja, moja moja. 366 00:21:17,460 --> 00:21:21,340 Aina ya kufikiri it up, unajua, kuteka kufyeka au comma katika baina yao. 367 00:21:21,340 --> 00:21:23,800 Na unaweza kubadilisha tu moja kwa moja chochote 368 00:21:23,800 --> 00:21:26,670 hii ni kwa kwanza idadi ya hexadecimal, 369 00:21:26,670 --> 00:21:29,880 na chochote hapa ni pili ya hexadesimoli. 370 00:21:29,880 --> 00:21:37,584 >> Basi kumbuka kutoka nukuu ya kawaida, je maadili hexadecimal kuanza na? 371 00:21:37,584 --> 00:21:38,460 >> Watazamaji: sifuri. 372 00:21:38,460 --> 00:21:39,270 >> PROFESA: 0x. 373 00:21:39,270 --> 00:21:45,210 Hivyo tunajua kwamba wakati wowote tunakuomba kubadili idadi yoyote ya hexadecimal, 374 00:21:45,210 --> 00:21:48,230 au wakati wowote unaweza kuona yoyote idadi hiyo inaanza na 0x, 375 00:21:48,230 --> 00:21:50,230 unajua kwamba ni thamani hexadecimal. 376 00:21:50,230 --> 00:21:54,160 >> Na kisha utaenda kuulizwa kuamua nini tarakimu hizi mbili ni. 377 00:21:54,160 --> 00:21:59,690 Na njia ya kufanya hivyo, kuhesabu up kuwa nusu na kuhesabu up kwamba nusu. 378 00:21:59,690 --> 00:22:02,870 Hivyo katika mfano huu, ni nini ingekuwa moja, moja, moja, moja kuwa? 379 00:22:02,870 --> 00:22:04,890 Nini thamani ingekuwa kwamba kuwa? 380 00:22:04,890 --> 00:22:06,040 Hiyo d kuwa F, sawa? 381 00:22:06,040 --> 00:22:08,050 Hiyo d kuwa 15. 382 00:22:08,050 --> 00:22:11,780 >> Hivyo hii itakuwa F. One, moja, moja, moja hapa ni pia 383 00:22:11,780 --> 00:22:21,270 F. Hivyo moja, moja, moja, moja, moja, moja, moja, moja katika hexadesimoli, yote ni ni 0XFF. 384 00:22:21,270 --> 00:22:25,350 Kwa sababu nusu huu kuwakilishwa F, thamani ya 15, 385 00:22:25,350 --> 00:22:27,331 na nusu huu kuwakilishwa F, thamani 15. 386 00:22:27,331 --> 00:22:29,456 Kwa sababu kumbuka, tuko kuhesabu kutoka sifuri hadi tisa. 387 00:22:29,456 --> 00:22:35,290 A ni kama 10, B ni kama 11, F ni 15. 388 00:22:35,290 --> 00:22:41,690 >> Je, hiyo mantiki kwa kila mtu jinsi tulipata kutoka mapacha kwa hexadesimoli? 389 00:22:41,690 --> 00:22:44,595 >> Watazamaji: Na hivyo jinsi gani sisi kupata 15 kutoka moja, moja, moja, moja? 390 00:22:44,595 --> 00:22:46,220 PROFESA: Yeah, hii ni mapacha, sawa? 391 00:22:46,220 --> 00:22:48,090 Fikiria hii ni idadi mapacha. 392 00:22:48,090 --> 00:22:50,792 Hivyo kuwa wawili kwa 0, ambayo ni moja. 393 00:22:50,792 --> 00:22:51,500 Watazamaji: Oh, Sawa. 394 00:22:51,500 --> 00:22:51,670 Hivyo wewe tu jumla nje. 395 00:22:51,670 --> 00:22:52,670 >> PROFESA: Yeah, na kisha wewe tu jumla kwamba nje. 396 00:22:52,670 --> 00:22:53,380 Hayo ni yote ni. 397 00:22:53,380 --> 00:22:54,890 >> Watazamaji: Sawa. 398 00:22:54,890 --> 00:22:55,830 >> PROFESA: Sawa. 399 00:22:55,830 --> 00:23:00,740 >> Watazamaji: Hivyo wewe kwenda kutoka mapacha kwa decimal ya hexadecimal? 400 00:23:00,740 --> 00:23:04,590 >> PROFESA: Hiyo ni Njia rahisi ya kufanya hivyo, yeah. 401 00:23:04,590 --> 00:23:11,390 Wewe si kwenda kwa decimal sababu alisema ana sifuri hadi tisa tu. 402 00:23:11,390 --> 00:23:13,410 Tuko tu aina ya kugawanyika huu juu katika wawili. 403 00:23:13,410 --> 00:23:15,201 >> Watazamaji: [inaudible] kutumia alisema kupata 404 00:23:15,201 --> 00:23:17,809 nini mechi hadi katika hexadesimoli. 405 00:23:17,809 --> 00:23:20,100 PROFESA: I mean, wewe ni kuhesabu kwa kutumia hisabati za msingi. 406 00:23:20,100 --> 00:23:20,725 Watazamaji: Naam. 407 00:23:20,725 --> 00:23:22,300 PROFESA: Yeah, pretty much. 408 00:23:22,300 --> 00:23:23,630 Ni kidogo utata. 409 00:23:23,630 --> 00:23:26,410 Lakini tu kujua kwamba wewe Unaweza kugawanya chochote 410 00:23:26,410 --> 00:23:28,160 thamani huu ni katika nusu tu. 411 00:23:28,160 --> 00:23:29,570 Angalia, ni nini hii katika binary? 412 00:23:29,570 --> 00:23:30,610 Nini idadi ni kwamba? 413 00:23:30,610 --> 00:23:33,270 Ni kwenda kuwa kitu kutoka sifuri hadi F. 414 00:23:33,270 --> 00:23:35,722 >> Hapa pia ni kwenda kuwa kitu kutoka sifuri hadi F. 415 00:23:35,722 --> 00:23:37,722 Na kisha unaweza kuweka tu hizo mbili pale pale. 416 00:23:37,722 --> 00:23:38,263 >> Watazamaji: Sawa. 417 00:23:38,263 --> 00:23:38,910 PROFESA: Yep. 418 00:23:38,910 --> 00:23:39,410 SAWA. 419 00:23:39,410 --> 00:23:42,320 Hivyo wewe guys wanataka kujaribu moja ijayo basi? 420 00:23:42,320 --> 00:23:49,601 Sifuri, moja, sifuri moja, moja, sifuri, moja sifuri. 421 00:23:49,601 --> 00:23:52,350 Mimi nitakupa guys kama sekunde 30, tangu wewe pengine hawakujua 422 00:23:52,350 --> 00:23:53,850 hila kwa jinsi ya kufanya hivyo mapema. 423 00:23:53,850 --> 00:24:24,950 424 00:24:24,950 --> 00:24:27,381 >> OK, mtu yeyote wanataka kupata risasi hili? 425 00:24:27,381 --> 00:24:28,774 >> 0X5A. 426 00:24:28,774 --> 00:24:29,440 PROFESA: 0X5A. 427 00:24:29,440 --> 00:24:30,470 5a. 428 00:24:30,470 --> 00:24:31,340 Nzuri. 429 00:24:31,340 --> 00:24:37,050 Hivyo hii hapa ingekuwa be-- unataka kutuambia jinsi got kwamba? 430 00:24:37,050 --> 00:24:38,920 Kwanza, umeingiaje tano? 431 00:24:38,920 --> 00:24:42,030 >> Watazamaji: Kwa sababu sifuri, moja, sifuri, moja ni watano. 432 00:24:42,030 --> 00:24:45,170 >> PROFESA: Je, kila mtu kuelewa kwa nini sifuri, moja, sifuri, moja ni tano? 433 00:24:45,170 --> 00:24:46,260 Nimepata moja hapa. 434 00:24:46,260 --> 00:24:48,010 Una kitu katika wawili kwa kwanza. 435 00:24:48,010 --> 00:24:50,300 Vipande viwili kwa pili, wewe kuwa moja, ambayo ni nne. 436 00:24:50,300 --> 00:24:52,600 Hivyo kuongeza pamoja nne moja, una tano. 437 00:24:52,600 --> 00:24:53,600 Kila mtu mwema? 438 00:24:53,600 --> 00:24:54,100 SAWA. 439 00:24:54,100 --> 00:24:56,570 Na kisha nini hii na kwa nini? 440 00:24:56,570 --> 00:24:58,350 Nini idadi gani A yanahusiana na? 441 00:24:58,350 --> 00:24:59,350 >> Watazamaji: 10. 442 00:24:59,350 --> 00:25:00,976 >> PROFESA: Na nini hii katika msingi mawili hata lini? 443 00:25:00,976 --> 00:25:01,850 Watazamaji: [inaudible] 444 00:25:01,850 --> 00:25:03,010 PROFESA: Hasa. 445 00:25:03,010 --> 00:25:06,370 Hivyo hii thamani pili hapa itakuwa 0X5A. 446 00:25:06,370 --> 00:25:08,410 >> Kila mtu mzuri kuhusu jinsi ya kubadilisha? 447 00:25:08,410 --> 00:25:10,770 Ni rahisi sana kuliko unafikiri ni. 448 00:25:10,770 --> 00:25:13,330 Nataka tu kuhakikisha unajua tips msaada 449 00:25:13,330 --> 00:25:14,950 na mbinu kwa jinsi ya kufanya hivyo. 450 00:25:14,950 --> 00:25:18,432 >> Watazamaji: Kwa nini unaweza tu kupasuliwa ni katikati kama hayo? 451 00:25:18,432 --> 00:25:21,390 Tu kuwa kama, sawa, mimi nina kwenda tu kwa huduma kuhusu hizi kwanza [inaudible]? 452 00:25:21,390 --> 00:25:24,240 >> PROFESA: Kwa sababu hiyo ni kweli njia maadili hexadecimal ni kuwakilishwa. 453 00:25:24,240 --> 00:25:26,890 0x, kwamba kwa kweli ina maana chochote zaidi nawaambia 454 00:25:26,890 --> 00:25:28,710 kuwa ni hexadesimoli idadi. 455 00:25:28,710 --> 00:25:31,580 Na hii mara zote inawakilisha nne za kwanza tarakimu. 456 00:25:31,580 --> 00:25:34,330 Na hii mara zote inawakilisha mwisho nne ya tarakimu. 457 00:25:34,330 --> 00:25:37,835 Na hivyo tarakimu hizi mbili tu yanahusiana na vipande mbalimbali. 458 00:25:37,835 --> 00:25:39,200 >> Watazamaji: Hivyo sisi always-- 459 00:25:39,200 --> 00:25:41,830 >> PROFESA: Wewe ni daima kwenda kupata nane thamani bits. 460 00:25:41,830 --> 00:25:44,580 >> Watazamaji: Je, hivyo tu kama jambo hapa au kwamba kitu duniani? 461 00:25:44,580 --> 00:25:46,883 PROFESA: Hiyo tu Jambo katika kompyuta, yep. 462 00:25:46,883 --> 00:25:47,424 Watazamaji: Sawa. 463 00:25:47,424 --> 00:25:48,240 Kutisha. 464 00:25:48,240 --> 00:25:51,290 >> PROFESA: Pia, hivyo katika mfano huu sisi kubadilishwa kutoka mapacha kwa decimal, 465 00:25:51,290 --> 00:25:53,290 na kutoka mapacha kwa hexadesimoli. 466 00:25:53,290 --> 00:25:56,610 Nyie unataka kuhakikisha wewe pia mazoezi kwenda njia nyingine kote. 467 00:25:56,610 --> 00:26:03,370 Hivyo kama mimi alitoa wewe 0XFF, ungeweza kuteka kwamba nje katika binary, sawa? 468 00:26:03,370 --> 00:26:06,820 >> Kubadilisha F katika binary, ambayo ni moja, moja, moja, moja, 469 00:26:06,820 --> 00:26:09,380 kubadilisha F kwa binary, ambayo ni moja, moja, moja, moja. 470 00:26:09,380 --> 00:26:11,310 >> Hivyo tunaweza kuuliza wewe kufanya njia nyingine kote. 471 00:26:11,310 --> 00:26:14,817 Hivyo alisema kwa binary, au hexadecimal kwa mapacha. 472 00:26:14,817 --> 00:26:16,650 Kwa hiyo unataka kufanya uhakika unajua njia zote mbili. 473 00:26:16,650 --> 00:26:19,371 Tutaweza pengine kuuliza macho ya mbili. 474 00:26:19,371 --> 00:26:20,660 >> Yeah, una swali? 475 00:26:20,660 --> 00:26:22,724 Siwezi see-- wewe ni vizuri? 476 00:26:22,724 --> 00:26:23,348 Watazamaji: Naam. 477 00:26:23,348 --> 00:26:24,560 PROFESA: Sawa. 478 00:26:24,560 --> 00:26:26,101 Mimi ni nzuri ili kufuta hili? 479 00:26:26,101 --> 00:26:26,600 Kubwa. 480 00:26:26,600 --> 00:26:33,965 481 00:26:33,965 --> 00:26:40,437 >> Haki wote, hivyo majibu ni hapa kama kuna mtu ni wadadisi baadaye na kupata kuchanganyikiwa. 482 00:26:40,437 --> 00:26:41,844 SAWA. 483 00:26:41,844 --> 00:26:46,070 >> Watazamaji: Je, ni jambo kama sisi kuweka barua yetu katika mji mkuu au lowercase? 484 00:26:46,070 --> 00:26:50,360 >> PROFESA: Ni gani, kwa sababu katika hexadesimoli, na mkataba huo, 485 00:26:50,360 --> 00:26:52,840 wahusika wote ni uppercase. 486 00:26:52,840 --> 00:26:54,650 Hivyo kupitia F ni kwenda kuwa uppercase. 487 00:26:54,650 --> 00:26:58,660 Kama kuweka ndogo a, sijui kama tunataka lazima alama yake vibaya. 488 00:26:58,660 --> 00:27:00,679 Lakini kinadharia, hiyo ni si kitaalam 489 00:27:00,679 --> 00:27:01,970 jinsi wewe walidhani kuwa nayo. 490 00:27:01,970 --> 00:27:03,303 Basi lazima wote uppercase. 491 00:27:03,303 --> 00:27:05,910 Yeah, swali zuri. 492 00:27:05,910 --> 00:27:07,780 >> SAWA. 493 00:27:07,780 --> 00:27:08,790 Pili swali. 494 00:27:08,790 --> 00:27:12,750 Fikiria mpango huu lovely hapa. 495 00:27:12,750 --> 00:27:15,180 Mimi itabidi kuuliza swali, Nitarudi hii. 496 00:27:15,180 --> 00:27:23,170 >> Hivyo, kwanza, nini ndani ya kiwango cha io.h hiyo ni ya manufaa kwa mpango? 497 00:27:23,170 --> 00:27:26,640 Pili, ni nini utupu yanamaanisha katika mstari tatu? 498 00:27:26,640 --> 00:27:30,572 Na tatu, ni nini kurudi sifuri kutoka kuu, kama mstari sita, kwa ujumla yanamaanisha? 499 00:27:30,572 --> 00:27:33,280 Kama nyie unataka kuandika wale chini, tangu nina kubadili nyuma 500 00:27:33,280 --> 00:27:36,810 kwa slide tu hivyo unaweza kuona kanuni. 501 00:27:36,810 --> 00:27:40,400 Huu ni mfano wa, kama, labda swali ngazi za juu ambapo tunakuomba 502 00:27:40,400 --> 00:27:42,435 mambo maana katika mpango huo. 503 00:27:42,435 --> 00:27:47,290 504 00:27:47,290 --> 00:27:49,215 >> Kila mtu mwema kwa ajili yangu na kurudi nyuma na slide? 505 00:27:49,215 --> 00:27:53,400 506 00:27:53,400 --> 00:27:54,361 OK, baridi. 507 00:27:54,361 --> 00:27:57,610 Hivyo mimi nitakupa guys kama labda tatu dakika ya kuangalia moja ya haraka hii ya kweli. 508 00:27:57,610 --> 00:28:41,330 509 00:28:41,330 --> 00:28:44,140 >> OK, hivyo hii moja ya kama haki rahisi, conceptually. 510 00:28:44,140 --> 00:28:49,280 Je, mtu yeyote wanataka kuniambia nini kwanza ndani ya hash na ikiwa ni pamoja na 511 00:28:49,280 --> 00:28:52,630 kiwango chetu io.h maktaba faili? 512 00:28:52,630 --> 00:28:55,510 Kwa nini tunahitaji kuwa maktaba pamoja na kwa mpango huu? 513 00:28:55,510 --> 00:28:56,930 Nini hapa tunahitaji ni kwa? 514 00:28:56,930 --> 00:28:56,980 >> Yeah? 515 00:28:56,980 --> 00:28:58,340 >> Watazamaji: Je, kwamba wakati kuweka kwamba printf? 516 00:28:58,340 --> 00:28:59,131 >> PROFESA: Hasa. 517 00:28:59,131 --> 00:29:01,780 Hivyo printf, wakati wowote kuchukua pembejeo kutoka kwa mtumiaji 518 00:29:01,780 --> 00:29:04,140 na magazeti kitu screen, hiyo ni 519 00:29:04,140 --> 00:29:05,600 pembejeo kiwango, maktaba pato. 520 00:29:05,600 --> 00:29:07,170 Fikiria ni kwamba way-- pembejeo, pato. 521 00:29:07,170 --> 00:29:08,430 >> Je nina pato? 522 00:29:08,430 --> 00:29:09,207 Ndiyo, mimi kufanya. 523 00:29:09,207 --> 00:29:12,040 Hivyo najua kwamba mimi nina daima kwenda haja maktaba standardize i.o. 524 00:29:12,040 --> 00:29:16,400 >> Hivyo printf ni kazi ambayo tunahitaji kupata 525 00:29:16,400 --> 00:29:19,370 na hashtag ni pamoja na kiwango cha i.o maktaba. 526 00:29:19,370 --> 00:29:20,280 SAWA. 527 00:29:20,280 --> 00:29:22,660 >> Pili, je, utupu yanamaanisha? 528 00:29:22,660 --> 00:29:26,970 Tuna int kuu (utupu), ni nini utupu hapa maana hapa kwenye mstari tatu? 529 00:29:26,970 --> 00:29:28,080 Yeah, katika nyuma. 530 00:29:28,080 --> 00:29:29,020 >> Watazamaji: [inaudible] 531 00:29:29,020 --> 00:29:29,920 >> PROFESA: Hasa. 532 00:29:29,920 --> 00:29:33,320 Basi kumbuka, tumejifunza kuanzia na pset yetu 533 00:29:33,320 --> 00:29:35,360 kuwa unaweza kweli kutaja mstari amri 534 00:29:35,360 --> 00:29:39,010 hoja kwamba mpango wako, kwamba Kazi kuu, inachukua kama wewe, mtumiaji, 535 00:29:39,010 --> 00:29:39,650 simu yake. 536 00:29:39,650 --> 00:29:42,650 Kama tuna batili, hiyo ina maana kwamba wewe inaweza tu kukimbia mpango moja kwa moja 537 00:29:42,650 --> 00:29:44,680 bila yoyote hoja mstari amri. 538 00:29:44,680 --> 00:29:46,160 Kila mtu wazi juu ya hilo? 539 00:29:46,160 --> 00:29:46,660 SAWA. 540 00:29:46,660 --> 00:29:52,850 >> Na mwisho kwa nini sisi kujisumbua kufanya hii kitu kurudi sifuri hapa? 541 00:29:52,850 --> 00:29:54,740 Kwa nini sisi hata kuwa int kuu? 542 00:29:54,740 --> 00:29:57,330 Kwa nini hatuwezi tu na utupu kuu utupu? 543 00:29:57,330 --> 00:29:59,216 Yeah? 544 00:29:59,216 --> 00:30:01,590 Watazamaji: Hivyo tu kwamba tunaweza kuwa na uhakika kuwa mpango huo ni 545 00:30:01,590 --> 00:30:04,247 exiting kwa mafanikio, kama kinyume na kama ilikuwa kuhesabiwa. 546 00:30:04,247 --> 00:30:06,580 Na tunataka kujua kwamba hiyo ni aina mbalimbali ya upotevu. 547 00:30:06,580 --> 00:30:07,621 >> PROFESA: Yeah, kwa uhakika. 548 00:30:07,621 --> 00:30:10,670 Hii ni sana Jambo kawaida kwamba sisi kufanya, 549 00:30:10,670 --> 00:30:13,840 ni kwamba tu mwishoni mwa mpango wako, tu kuhakikisha 550 00:30:13,840 --> 00:30:15,830 kwamba kazi yako kuu anagombea kwa usahihi, 551 00:30:15,830 --> 00:30:17,940 sisi daima wanataka kufanya kurudi sifuri. 552 00:30:17,940 --> 00:30:21,160 Hata kama tunaweza lazima hawaoni kwamba kuchapishwa mahali popote. 553 00:30:21,160 --> 00:30:25,092 >> Kwa sababu kama programmers, unajua, kama una mengi ya mistari tofauti ya maadili 554 00:30:25,092 --> 00:30:27,050 na wewe sijui wapi haya ni kwenda vibaya, 555 00:30:27,050 --> 00:30:30,240 na kama kosa hutokea unataka kuhakikisha kuwa wewe kupata kosa hilo. 556 00:30:30,240 --> 00:30:33,240 Na hivyo kawaida kama kitu fulani kitaenda vibaya tutaweza kuwa kurudi kwa moja tu 557 00:30:33,240 --> 00:30:34,669 kuhakikisha tunajua kwamba ni. 558 00:30:34,669 --> 00:30:36,460 Hivyo kama unaweza kuona kurudi sifuri, kwamba kwa kawaida 559 00:30:36,460 --> 00:30:38,293 ina maana mpango wako ni kunyongwa kwa mafanikio. 560 00:30:38,293 --> 00:30:40,490 561 00:30:40,490 --> 00:30:40,990 Nzuri? 562 00:30:40,990 --> 00:30:45,180 563 00:30:45,180 --> 00:30:45,680 Baridi. 564 00:30:45,680 --> 00:30:48,710 565 00:30:48,710 --> 00:30:52,680 >> Sawa, mpango wa pili hapa. 566 00:30:52,680 --> 00:30:54,827 Fikiria jambo hilo. 567 00:30:54,827 --> 00:30:56,910 Na kama nyie ona kuelea, nyie Unaweza pengine 568 00:30:56,910 --> 00:31:00,810 kuwa na wazo nzuri ya nini Mimi nina kuhusu kuuliza. 569 00:31:00,810 --> 00:31:05,200 >> Hivyo wakati mpango huu executes, kama unaweza kuona, 570 00:31:05,200 --> 00:31:09,330 Mimi kutangaza kuelea ndani ya kazi yangu kuu. 571 00:31:09,330 --> 00:31:13,470 Mimi kutaja ni "kujibu," na mimi nina kuweka kuwa sawa na mtu kugawanywa na 10. 572 00:31:13,470 --> 00:31:17,860 Mimi uchapishaji nje, kwa moja mahali alisema kwamba kuelea. 573 00:31:17,860 --> 00:31:19,880 Na kisha mimi nina kurudi sifuri. 574 00:31:19,880 --> 00:31:24,470 >> Hivyo wakati utekelezaji wa mpango, kufikiri nyuma kwa tamaa sasa, 575 00:31:24,470 --> 00:31:26,550 mpango huu Prints 0.0. 576 00:31:26,550 --> 00:31:29,993 Kama sisi wote kujua, pengine sisi wote Unajua, moja kugawanywa na 10 ni si 0.00, 577 00:31:29,993 --> 00:31:32,350 ni 0.1. 578 00:31:32,350 --> 00:31:37,810 Lakini kueleza kwa nini mpango huu anadhani kuwa 1 kugawanywa na 10 prints kwa 0.1 mengine 579 00:31:37,810 --> 00:31:39,504 ya 0.1? 580 00:31:39,504 --> 00:31:42,545 Mimi nitakupa guys labda kama 30 sekunde kwa haraka tu kufikiri juu ya kwamba 581 00:31:42,545 --> 00:31:43,878 na mimi itabidi kurudi nyuma na mpango huo. 582 00:31:43,878 --> 00:32:17,800 583 00:32:17,800 --> 00:32:20,290 >> SAWA. 584 00:32:20,290 --> 00:32:22,205 Mtu yeyote wanataka kuwapa risasi? 585 00:32:22,205 --> 00:32:24,330 Katika hukumu tatu au chini, kwa sababu kwa kawaida tuko 586 00:32:24,330 --> 00:32:27,650 kwenda kuzuia majibu yote kwa hukumu tatu au chini 587 00:32:27,650 --> 00:32:31,130 hivyo huna tu regurgitate mambo random kwenye jaribio yako. 588 00:32:31,130 --> 00:32:32,740 >> Naam, kuchukua risasi. 589 00:32:32,740 --> 00:32:36,390 >> Watazamaji: Hivyo nadhani kuna hii Jambo kuitwa, kama, [inaudible] 590 00:32:36,390 --> 00:32:42,320 Hivyo huenda kuna, kwa mfano, huenda kuna, kama, 0.09, 591 00:32:42,320 --> 00:32:47,250 kwamba ambapo magazeti kwanza tarakimu, itakuwa kwa 0.0? 592 00:32:47,250 --> 00:32:49,100 >> PROFESA: Karibu, si kabisa. 593 00:32:49,100 --> 00:32:49,810 Christabell? 594 00:32:49,810 --> 00:32:51,770 >> Watazamaji: Wewe ni kugawa moja na 10, na wao uko integers zote mbili. 595 00:32:51,770 --> 00:32:54,610 Na hivyo kwa njia hiyo itakuja kuhifadhi ni kama integer. 596 00:32:54,610 --> 00:32:56,480 Na hivyo integer karibu itakuwa 0.0. 597 00:32:56,480 --> 00:32:57,471 Na hivyo ndiyo 0.1. 598 00:32:57,471 --> 00:32:58,970 PROFESA: Yeah, hiyo ni nzuri kwa kweli. 599 00:32:58,970 --> 00:33:00,040 Hiyo ni jibu sahihi. 600 00:33:00,040 --> 00:33:03,597 Hivyo hii ni utata sana dhana kwa mengi ya watoto. 601 00:33:03,597 --> 00:33:06,680 Na kwa kweli mimi nataka kuhakikisha kuwa hii ni kushinikizwa katika kichwa kila mtu. 602 00:33:06,680 --> 00:33:10,090 >> Hivyo kile tunachokiita yaliyo hatua kutokuwa sahihi, 603 00:33:10,090 --> 00:33:12,800 ambapo sababu ni kwa nini kura wa mipango yako katika tamaa 604 00:33:12,800 --> 00:33:17,010 hakuwa na kazi ya awali ilikuwa ni kwa sababu alisahau kutupwa kutofautiana yako. 605 00:33:17,010 --> 00:33:19,370 Kwa hiyo kile Christabell alisema ilikuwa sahihi kabisa. 606 00:33:19,370 --> 00:33:21,990 >> Kuelea ni asili imprecise. 607 00:33:21,990 --> 00:33:26,400 Kwa sababu katika kompyuta, haki, tuna kiasi kidogo cha vipande vya kumbukumbu 608 00:33:26,400 --> 00:33:28,480 tunaweza kutumia kuwakilisha idadi. 609 00:33:28,480 --> 00:33:33,480 Hivyo, kwa mfano, hii ID CS50 is-- Nadhani ni kompyuta 64-bit. 610 00:33:33,480 --> 00:33:37,520 >> Kuelea inaweza tu kuwakilishwa na kiasi kidogo cha vipande hayo. 611 00:33:37,520 --> 00:33:42,260 Na hivyo 0.1 na zeros usio na mipaka, kwamba aliitwa 0.1 ni, sawa? 612 00:33:42,260 --> 00:33:45,450 Lakini hatuwezi kweli kuhifadhi kwamba idadi katika kompyuta yetu. 613 00:33:45,450 --> 00:33:47,810 Sisi tu hawana kumbukumbu ya kutosha ya kufanya hivyo. 614 00:33:47,810 --> 00:33:52,340 >> Na hivyo karibu zaidi ya makadirio ya nini kuhifadhiwa katika kumbukumbu ni kweli 615 00:33:52,340 --> 00:33:55,390 kitu kama 0.000 kitu, kitu, kitu, kitu fulani. 616 00:33:55,390 --> 00:34:01,240 Ambayo, mara moja butu hivyo, raundi chini ya 0.0. 617 00:34:01,240 --> 00:34:05,640 >> Na hivyo mfano hii ni moja tu kwamba inaonyesha kura ya masuala 618 00:34:05,640 --> 00:34:08,469 tuna wakati wowote tuko kujaribu kimakosa kufanya hesabu 619 00:34:08,469 --> 00:34:11,000 bila akitoa kama integer tofauti. 620 00:34:11,000 --> 00:34:14,870 Hivyo tu kuwa na wasiwasi wa jambo hili kutokea. 621 00:34:14,870 --> 00:34:18,239 >> On Quizzes, kama sisi kukupa kuzuia wa kanuni na ni kama, 622 00:34:18,239 --> 00:34:19,510 nini Prints nje mwishoni? 623 00:34:19,510 --> 00:34:24,096 Na kama ni baadhi ya thamani random wewe guys wanapaswa kujua kwa nini kinatokea. 624 00:34:24,096 --> 00:34:24,909 Yeah? 625 00:34:24,909 --> 00:34:27,926 >> Watazamaji: Truncate ni kujikwamua kila kitu baada ya hatua fulani? 626 00:34:27,926 --> 00:34:28,513 [Inaudible] 627 00:34:28,513 --> 00:34:30,929 PROFESA: Yeah, hivyo kweli huu ni mfano mbaya kweli kweli, 628 00:34:30,929 --> 00:34:37,870 kwa sababu 0.100 chochote kweli ingekuwa butu hadi 0.1. 629 00:34:37,870 --> 00:34:41,389 Lakini kama ungekuwa na kukimbia it-- mimi si kumbuka, kwa sababu mwaka jana wao 630 00:34:41,389 --> 00:34:42,830 mbio ni juu ya mpango tofauti. 631 00:34:42,830 --> 00:34:45,300 Wao mbio katika kitu kinachoitwa Appliance CS50, ambayo 632 00:34:45,300 --> 00:34:46,389 ni tofauti na ID. 633 00:34:46,389 --> 00:34:48,520 Hiyo ilikuwa ni mfumo wa 32-bit, nadhani. 634 00:34:48,520 --> 00:34:50,290 Na hivyo kulikuwa na idadi tofauti. 635 00:34:50,290 --> 00:34:53,330 >> Lakini kimsingi, tu kujua kwamba dhana nzima ya truncation 636 00:34:53,330 --> 00:34:54,815 na jinsi tu kupunguzwa mambo mbali. 637 00:34:54,815 --> 00:34:55,690 Na hivyo kama rounds-- 638 00:34:55,690 --> 00:34:56,300 >> Watazamaji: Bila rounding. 639 00:34:56,300 --> 00:34:57,370 >> PROFESA: Hasa. 640 00:34:57,370 --> 00:34:57,870 Naam. 641 00:34:57,870 --> 00:35:02,330 642 00:35:02,330 --> 00:35:04,380 Baridi. 643 00:35:04,380 --> 00:35:05,250 >> Hi, katika nyuma. 644 00:35:05,250 --> 00:35:07,634 Tunakwenda zaidi ya baadhi Jaribio mapitio maswali. 645 00:35:07,634 --> 00:35:08,430 >> Sawa. 646 00:35:08,430 --> 00:35:10,150 Hivyo kufikiria mpango tofauti hapa. 647 00:35:10,150 --> 00:35:12,797 648 00:35:12,797 --> 00:35:15,380 Mimi nina kwenda kukupa guys a dakika kadhaa kusoma juu ya hili. 649 00:35:15,380 --> 00:35:18,588 Hili ni jambo ambalo lilikuwa kwa sana Hivi karibuni kwamba nadhani akapiga mengi ya wewe 650 00:35:18,588 --> 00:35:19,142 guys ya akili. 651 00:35:19,142 --> 00:35:21,100 Lakini sisi ni kwenda kuzungumza kwa njia hii tena tu 652 00:35:21,100 --> 00:35:24,152 kuhakikisha kuelewa kabisa. 653 00:35:24,152 --> 00:35:24,652 SAWA. 654 00:35:24,652 --> 00:35:41,280 655 00:35:41,280 --> 00:35:41,780 SAWA. 656 00:35:41,780 --> 00:35:44,342 Mtu yeyote wanahitaji muda zaidi wa kusoma kwa njia ya kificho hili? 657 00:35:44,342 --> 00:35:45,650 SAWA. 658 00:35:45,650 --> 00:35:50,630 >> Hivyo inaonekana kwangu kuwa katika mpango huu mimi nina 659 00:35:50,630 --> 00:35:53,460 kujenga masharti mawili kwa kutumia GetString. 660 00:35:53,460 --> 00:35:55,180 Mtu mmoja aitwaye s na mtu mmoja aitwaye t. 661 00:35:55,180 --> 00:35:58,680 Na kama uko sawa sawa kwa kila mmoja, 662 00:35:58,680 --> 00:36:00,880 ni lazima magazeti "Wewe aina kitu kimoja. " 663 00:36:00,880 --> 00:36:04,170 >> Lakini elsewise, ingekuwa magazeti, "Wewe typed mambo mbalimbali, "sawa? 664 00:36:04,170 --> 00:36:05,990 Inaonekana sana, rahisi sana. 665 00:36:05,990 --> 00:36:08,720 Lakini, hata hivyo, kama mimi kwa kweli jaribu kuandika mpango huu, 666 00:36:08,720 --> 00:36:12,230 inaonekana kwamba hata wakati mimi pembejeo halisi masharti sawa, 667 00:36:12,230 --> 00:36:15,490 bado Prints nje, "Wewe typed mambo mbalimbali! " 668 00:36:15,490 --> 00:36:18,020 Je, mtu yeyote unataka kuchukua risasi katika nini mpango huu daima 669 00:36:18,020 --> 00:36:20,370 anajibu kwamba pembejeo za ni tofauti, hata 670 00:36:20,370 --> 00:36:22,090 wakati maneno yenyewe ni sawa? 671 00:36:22,090 --> 00:36:24,870 672 00:36:24,870 --> 00:36:29,170 >> Hivyo kama ningekuwa input-- David upendo kutumia mfano kama mama, sawa? 673 00:36:29,170 --> 00:36:37,890 Lowercase M-O-M kwa S, T sawa lowercase M-O-M. 674 00:36:37,890 --> 00:36:40,340 Kama mimi mbio hili kwa njia ya kwamba kanuni, kwa nini ni 675 00:36:40,340 --> 00:36:44,180 magazeti nje "uliyochapa mambo mbalimbali?" 676 00:36:44,180 --> 00:36:46,336 >> Je, mtu yeyote haja zaidi muda wa kufikiria kuhusu hili? 677 00:36:46,336 --> 00:36:47,294 Sawa, nafikiri sisi ni nzuri. 678 00:36:47,294 --> 00:36:48,716 Yeah? 679 00:36:48,716 --> 00:36:53,930 >> Watazamaji: Sawa, hivyo ni kitu kuhusu ambapo ni kuhifadhiwa katika kumbukumbu, sawa? 680 00:36:53,930 --> 00:36:54,890 >> PROFESA: Yep. 681 00:36:54,890 --> 00:37:00,400 >> Watazamaji: wapi ni kama, kama hii kamba s ni kuhifadhiwa katika kumbukumbu spot-- 682 00:37:00,400 --> 00:37:01,689 Mimi mzushi Haya ni sifuri. 683 00:37:01,689 --> 00:37:02,355 PROFESA: Ni kweli. 684 00:37:02,355 --> 00:37:05,290 Watazamaji: Na kamba t ni kuhifadhiwa katika kumbukumbu doa, 685 00:37:05,290 --> 00:37:11,000 kama, 167, na kisha sifuri haina sawa 167. 686 00:37:11,000 --> 00:37:12,610 >> PROFESA: Hasa. 687 00:37:12,610 --> 00:37:18,350 OK, hivyo kumbuka hii ya ajabu ufunuo sisi alielezea kwa nyie 688 00:37:18,350 --> 00:37:21,530 wiki hii iliyopita, kwamba masharti si kweli zipo? 689 00:37:21,530 --> 00:37:25,380 Wakati sisi kujenga kitu kinachoitwa kamba tuko, katika hali halisi, 690 00:37:25,380 --> 00:37:29,330 kujenga kitu kinachoitwa Char nyota. 691 00:37:29,330 --> 00:37:34,470 Ambao wote ni ni pointer kamba au kwa safu ya chars. 692 00:37:34,470 --> 00:37:39,480 >> Na hivyo katika mfano huu, ikiwa mimi walikuwa na pembejeo M-O-M njia 693 00:37:39,480 --> 00:37:49,350 kwamba kompyuta yangu ingekuwa kuhifadhi ni ndani ya kumbukumbu sifuri backslash, sawa? 694 00:37:49,350 --> 00:37:53,180 Wale nne wahusika, chars, itakuwa kuhifadhiwa mahali fulani. 695 00:37:53,180 --> 00:37:59,290 >> Na kisha hizi nne wahusika, sifuri backslash, 696 00:37:59,290 --> 00:38:01,275 ni kuhifadhiwa mahali pengine, sawa? 697 00:38:01,275 --> 00:38:04,685 Mimi sijui ambapo anwani ni, wao uko mahali fulani katika kompyuta yangu. 698 00:38:04,685 --> 00:38:07,080 Lakini mimi si hasa kujua walipo. 699 00:38:07,080 --> 00:38:10,170 >> Wakati mimi kujenga kamba s, kila kwamba kweli ni 700 00:38:10,170 --> 00:38:15,550 ni pointer kuanza ya kamba hii. 701 00:38:15,550 --> 00:38:21,130 Na wakati mimi kujenga thamani huu t, yote ambayo ni pointer kwa hapa. 702 00:38:21,130 --> 00:38:23,980 Na hivyo wakati wewe ni kujaribu equate na kuangalia 703 00:38:23,980 --> 00:38:27,710 ili kuona kama s ni sawa sawa na t, kompyuta 704 00:38:27,710 --> 00:38:31,635 ni kweli tu ya kurejea wewe pepe ya m huu 705 00:38:31,635 --> 00:38:33,390 na anuani ya kuwa m. 706 00:38:33,390 --> 00:38:36,230 Na kwa sababu wao ni wawili vipande tofauti vya data 707 00:38:36,230 --> 00:38:38,750 kwamba ni kuhifadhiwa katika mbili tofauti anwani katika kompyuta yako, 708 00:38:38,750 --> 00:38:41,750 kompyuta yako kamwe kwenda kutambua yao kama kuwa sawa. 709 00:38:41,750 --> 00:38:43,500 Je, mtu yeyote wanataka kutoa risasi katika kile sisi 710 00:38:43,500 --> 00:38:46,900 ingekuwa kufanya kama sisi alitaka kusahihisha huu na kuwa sahihi mpango mbio 711 00:38:46,900 --> 00:38:49,360 badala yake? 712 00:38:49,360 --> 00:38:52,070 Fikiria kwamba kwa sekunde kadhaa. 713 00:38:52,070 --> 00:38:54,929 Je, tunahitaji mabadiliko ya kupata hii kazi mpango 714 00:38:54,929 --> 00:38:56,220 njia tunataka kufanya kazi? 715 00:38:56,220 --> 00:39:17,260 716 00:39:17,260 --> 00:39:18,918 >> Naam, nataka kuchukua kumchoma katika hilo? 717 00:39:18,918 --> 00:39:24,082 >> Watazamaji: Je, sisi kujaribu dereference pointer na kuangalia kupitia safu? 718 00:39:24,082 --> 00:39:25,540 PROFESA: Hiyo ni njia moja ya kufanya hivyo. 719 00:39:25,540 --> 00:39:27,880 Hivyo, nini jina yako tena? 720 00:39:27,880 --> 00:39:29,010 Samahani, unikumbushe. 721 00:39:29,010 --> 00:39:29,589 >> Zee: Zee. 722 00:39:29,589 --> 00:39:32,130 PROFESA: Yeah, hivyo nini Zee alipendekeza ingekuwa kabisa kazi. 723 00:39:32,130 --> 00:39:32,629 Sawa? 724 00:39:32,629 --> 00:39:35,730 Tunaweza dereference pointer na kweli kwenda na upatikanaji 725 00:39:35,730 --> 00:39:38,460 data ya kimwili ndani ya hapa. 726 00:39:38,460 --> 00:39:40,300 Na tunaweza tu kulinganisha screen nzima. 727 00:39:40,300 --> 00:39:43,670 >> Tunaweza kusema, sawa, pointer, nipe nini ndani hapa. 728 00:39:43,670 --> 00:39:44,960 Itakuwa kurudi m. 729 00:39:44,960 --> 00:39:47,168 Na naweza kusema, pointer, nipe nini ndani hapa. 730 00:39:47,168 --> 00:39:47,750 Kurudi m. 731 00:39:47,750 --> 00:39:48,410 Je, wale mechi? 732 00:39:48,410 --> 00:39:49,410 Ndiyo. 733 00:39:49,410 --> 00:39:50,340 Kisha sisi kusonga mbele. 734 00:39:50,340 --> 00:39:54,240 >> Sisi kuendelea kuangalia mbili nzima masharti njia yote hadi mpaka mwisho 735 00:39:54,240 --> 00:39:56,635 na kuona kama hizo ni sawa, kama maadili yote ni sawa. 736 00:39:56,635 --> 00:39:59,680 Na kama maadili yote ni sawa, basi tunajua masharti ni kweli. 737 00:39:59,680 --> 00:40:01,600 Kabisa, hiyo ni jinsi tunataka kufanya hivyo? 738 00:40:01,600 --> 00:40:03,930 >> Je, mtu yeyote kuchanganyikiwa yoyote ya hili? 739 00:40:03,930 --> 00:40:06,970 Dhana nzima ya jinsi masharti ni kuyatumia kweli tu, 740 00:40:06,970 --> 00:40:08,440 na jinsi wao si kweli zipo? 741 00:40:08,440 --> 00:40:10,480 Na kwa nini sisi kupata makosa kama njia ya sisi kupata? 742 00:40:10,480 --> 00:40:15,070 Kwa sababu mimi kuhakikisha nyie, kuyatumia na kamba mgao na kumbukumbu 743 00:40:15,070 --> 00:40:16,470 yatakuja juu. 744 00:40:16,470 --> 00:40:17,410 >> Yeah? 745 00:40:17,410 --> 00:40:21,072 >> Watazamaji: [inaudible] dereference hivyo, wewe tu kuweka nyota [inaudible] 746 00:40:21,072 --> 00:40:21,780 PROFESA: Haki. 747 00:40:21,780 --> 00:40:28,430 Hivyo kwa derererence pointer njia kwenda kuwa pepe ya pointer 748 00:40:28,430 --> 00:40:30,390 na kupata taarifa, thamani huko. 749 00:40:30,390 --> 00:40:32,700 Na njia ya kufanya hivyo ni nyota pointer. 750 00:40:32,700 --> 00:40:34,262 Usiwachanganye hiyo. 751 00:40:34,262 --> 00:40:35,186 >> Watazamaji: [inaudible]. 752 00:40:35,186 --> 00:40:35,852 >> PROFESA: Naam. 753 00:40:35,852 --> 00:40:39,750 Watazamaji: Hivyo unaweza tu kuandika kama nyota s sawa sawa nyota t. 754 00:40:39,750 --> 00:40:40,630 >> PROFESA: Naam, hapana. 755 00:40:40,630 --> 00:40:40,960 Hakuna 756 00:40:40,960 --> 00:40:41,640 >> Watazamaji: Hiyo siyo nzuri ya kutosha, sawa? 757 00:40:41,640 --> 00:40:43,760 >> PROFESA: Siyo, kwa sababu wewe ni kuangalia tu barua ya kwanza. 758 00:40:43,760 --> 00:40:46,010 Pengine wewe kwenda kwa haja baadhi ya aina ya kitanzi kwamba 759 00:40:46,010 --> 00:40:49,055 iterates kwa njia ya kila mmoja tabia katika masharti yote mawili. 760 00:40:49,055 --> 00:40:49,837 Naam. 761 00:40:49,837 --> 00:40:52,920 Hivyo kama alitaka kuangalia tu kuona kama ilianza na kitu kimoja, 762 00:40:52,920 --> 00:40:58,220 unaweza kufanya kama, nyota s ni sawa na nyota t. 763 00:40:58,220 --> 00:41:01,300 Basi, unajua kwamba angalau wao ilianza na tabia hiyo. 764 00:41:01,300 --> 00:41:01,952 >> Yeah? 765 00:41:01,952 --> 00:41:04,056 >> Watazamaji: Hivyo njia huna kwamba itakuwa 766 00:41:04,056 --> 00:41:06,064 kama iliyoingia kwa kitanzi au pointer? 767 00:41:06,064 --> 00:41:06,730 PROFESA: Naam. 768 00:41:06,730 --> 00:41:08,170 Pretty much tu kwa kitanzi. 769 00:41:08,170 --> 00:41:12,430 Kumbuka, Daudi darasani zilizotajwa bure kisintaksia sukari? 770 00:41:12,430 --> 00:41:17,690 Naye alikuwa na haya sana Jambo utata wa nyota t 771 00:41:17,690 --> 00:41:22,030 pamoja na moja, ambapo itakuwa kuunganisha kupitia na hoja ya pointer? 772 00:41:22,030 --> 00:41:29,910 Njia rahisi ya kufanya hii ni t ya i. 773 00:41:29,910 --> 00:41:31,090 >> Hivyo ni tu safu. 774 00:41:31,090 --> 00:41:34,630 Njia hiyo ingekuwa kwa kitanzi kwamba mbio kutoka sifuri kwa i, ambapo 775 00:41:34,630 --> 00:41:36,580 i ni urefu wa kamba, ungeweza tu 776 00:41:36,580 --> 00:41:39,510 kuandika kwamba badala ya kufanya pointer nzima, akimaanisha kitu. 777 00:41:39,510 --> 00:41:43,510 Hivyo mambo haya ni hasa sawa katika kompyuta yako. 778 00:41:43,510 --> 00:41:45,905 >> Nyie pengine si wanahitaji kujua kwamba, 779 00:41:45,905 --> 00:41:48,280 lakini ni vizuri tu aina ya kuwa katika nyuma ya akili yako. 780 00:41:48,280 --> 00:41:52,630 Tu kujua kwamba kompyuta inatambua vitalu mbalimbali ya maadili 781 00:41:52,630 --> 00:41:53,890 kama kitu kimoja. 782 00:41:53,890 --> 00:41:57,510 Kwa sababu hii ni mbali zaidi user kirafiki kwa sisi sasa ni kama ni 783 00:41:57,510 --> 00:41:58,150 safu. 784 00:41:58,150 --> 00:42:00,990 Ni rahisi tu. 785 00:42:00,990 --> 00:42:02,719 >> Watazamaji: Hivyo kutumia strlen kama, get-- 786 00:42:02,719 --> 00:42:03,385 PROFESA: Naam. 787 00:42:03,385 --> 00:42:03,926 Watazamaji: Sawa. 788 00:42:03,926 --> 00:42:05,940 PROFESA: Ungeweza kutumia strlen au, kama 789 00:42:05,940 --> 00:42:10,420 hawakuwa na strlen unaweza tu kufanya up mpaka hit sifuri backslash kwa wote. 790 00:42:10,420 --> 00:42:11,568 Aidha ingekuwa kazi. 791 00:42:11,568 --> 00:42:12,068 Naam. 792 00:42:12,068 --> 00:42:14,871 793 00:42:14,871 --> 00:42:17,996 Watazamaji: Hivyo ni dereference kila tabia moja kama tulikuwa kweli 794 00:42:17,996 --> 00:42:21,044 kuandika kanuni hii, sisi inaweza tu kufanya mabano t i 795 00:42:21,044 --> 00:42:22,460 kama na nyota mbele yake? 796 00:42:22,460 --> 00:42:27,700 >> PROFESA: Yeah, sawa sawa s mabano i, na kisha kusonga i 797 00:42:27,700 --> 00:42:29,790 chini hadi kugonga mwisho. 798 00:42:29,790 --> 00:42:31,286 Yeah, hiyo ni nini ungependa kufanya. 799 00:42:31,286 --> 00:42:33,660 Na mimi itabidi kweli kuwa ijayo mfano wa wakati sisi kweli 800 00:42:33,660 --> 00:42:36,740 kuandika strlen hivyo nyie mapenzi aina ya kupata kucheza karibu na hayo kidogo. 801 00:42:36,740 --> 00:42:43,567 >> Ndivyo ilivyo kwa mtu wazi juu ya kumbukumbu tu, masharti, kuyatumia, ubora anwani? 802 00:42:43,567 --> 00:42:46,650 Baadhi ya dhana ngazi za juu kuwa wewe mapenzi kwa haja uhakika wa kujua juu ya jaribio 803 00:42:46,650 --> 00:42:48,928 kesho. 804 00:42:48,928 --> 00:42:49,904 >> Sawa. 805 00:42:49,904 --> 00:42:50,404 Nzuri. 806 00:42:50,404 --> 00:42:54,824 807 00:42:54,824 --> 00:42:55,324 Yep. 808 00:42:55,324 --> 00:42:58,770 809 00:42:58,770 --> 00:43:04,180 OK, hivyo jambo moja kwamba tutaweza pia kuuliza wewe, kama sisi kufanya kila mwaka juu ya jaribio, ni, 810 00:43:04,180 --> 00:43:08,340 tuseme kwamba tumesahau (ambayo tunaonekana kusahau kufanya kila mwaka) 811 00:43:08,340 --> 00:43:10,810 ambao kichwa faili strlen ni alitangaza. 812 00:43:10,810 --> 00:43:13,860 Na hivyo inabidi kuandika upya wenyewe. 813 00:43:13,860 --> 00:43:16,350 >> Hapa ni orodha ya miongozo tuweze sasa wewe 814 00:43:16,350 --> 00:43:20,660 guys ambapo unaweza kupata kudhani kuwa s kamba haitakuwa null. 815 00:43:20,660 --> 00:43:23,830 Unaweza kudhani kuwa s itakuwa kuachishwa na backslash sifuri. 816 00:43:23,830 --> 00:43:26,670 Hivyo unajua kwamba ni nini itakuja mwisho na. 817 00:43:26,670 --> 00:43:29,500 >> Na, kwa mfano, kwamba urefu wa hodi itakuwa tano. 818 00:43:29,500 --> 00:43:32,890 Hivyo unaweza kudhani kuwa hodi Itakuwa tano, H-E-L-L-O. 819 00:43:32,890 --> 00:43:35,890 Huwezi kuwa kudhani kuwa backside sifuri akaunti kwa urefu. 820 00:43:35,890 --> 00:43:39,720 821 00:43:39,720 --> 00:43:42,300 >> Hii jambo la mwisho hapa, hawana wasiwasi kuhusu integer kufurika. 822 00:43:42,300 --> 00:43:45,270 Je, mtu yeyote kumbuka nini integer kufurika ni? 823 00:43:45,270 --> 00:43:48,041 >> Watazamaji: Goes zaidi urefu wa [inaudible]. 824 00:43:48,041 --> 00:43:50,740 >> PROFESA: Yeah, unaweza kueleza kidogo, hiyo ina maana gani? 825 00:43:50,740 --> 00:43:55,330 >> Watazamaji: Hivyo, mimi nadhani unaendelea nyuma kwa mfano truncating mapema. 826 00:43:55,330 --> 00:43:58,380 Lakini kama una tu idadi mingi kwamba kwenda zaidi ya idadi ya bits 827 00:43:58,380 --> 00:44:01,409 kwamba unaweza kweli hawawajui kwamba itakuwa tu aina ya kukatwa. 828 00:44:01,409 --> 00:44:04,242 PROFESA: Yeah, kadhalika kawaida kompyuta, jinsi vipande wengi hawana tuna? 829 00:44:04,242 --> 00:44:05,306 Watazamaji: 32? 830 00:44:05,306 --> 00:44:06,430 PROFESA: Yeah, 32, wa kulia. 831 00:44:06,430 --> 00:44:10,030 Na hivyo ndiyo, ni nini, nne bilioni, bilioni mbili? 832 00:44:10,030 --> 00:44:13,579 Nne bilioni, hadi bilioni nne integers chanya, sawa? 833 00:44:13,579 --> 00:44:15,370 Bilioni mbili hasi, bilioni mbili chanya, 834 00:44:15,370 --> 00:44:16,900 inategemea jinsi gani unataka kufanya hivyo. 835 00:44:16,900 --> 00:44:21,470 >> Na hivyo kimsingi tunaweza kuwa integers kutosha kwamba unaweza kwenda juu 836 00:44:21,470 --> 00:44:25,800 kwa mawili kwa 31 bala 1, sawa? 837 00:44:25,800 --> 00:44:27,980 Kwa sababu mara moja sisi kugonga mbili kwa 32, hatufanyi 838 00:44:27,980 --> 00:44:30,040 na kwamba kumbukumbu nyingi katika kompyuta yetu. 839 00:44:30,040 --> 00:44:32,310 >> Na hivyo, kinadharia, mimi tunaweza kuja na idadi 840 00:44:32,310 --> 00:44:34,560 yaani, kama, mbili kwa 46. 841 00:44:34,560 --> 00:44:38,040 Ni kubwa-punda idadi, lakini kinadharia unaweza. 842 00:44:38,040 --> 00:44:42,730 Na hivyo integer kufurika ni kama kujaribu kujenga integer kwamba huenda zaidi ya kile 843 00:44:42,730 --> 00:44:44,790 kompyuta yako ni uwezo wa kuhifadhi. 844 00:44:44,790 --> 00:44:46,590 >> Na hivyo nyie kwa mfano huu hawana 845 00:44:46,590 --> 00:44:51,330 na wasiwasi kuhusu sisi kutoa kubwa kamba kwamba ni wawili kwa chars 32 846 00:44:51,330 --> 00:44:51,830 muda mrefu. 847 00:44:51,830 --> 00:44:54,010 Kwamba itakuwa kweli maana. 848 00:44:54,010 --> 00:44:59,430 >> Haki wote, hivyo mimi nina kwenda tu kukupa nyie muundo msingi wa hili. 849 00:44:59,430 --> 00:45:02,020 Wewe ni kwenda kujenga kazi kuitwa int strlen ambapo 850 00:45:02,020 --> 00:45:08,436 a kupita katika, nyota Char, au kamba, pointer kamba kuitwa s. 851 00:45:08,436 --> 00:45:10,820 >> Wote haki, kila mtu nakala kwamba chini. 852 00:45:10,820 --> 00:45:13,550 853 00:45:13,550 --> 00:45:14,850 Baridi. 854 00:45:14,850 --> 00:45:17,020 Njia nyingine Oops--. 855 00:45:17,020 --> 00:45:21,360 >> Hivyo hii ni aina ya kama vigumu kipande cha tatizo, 856 00:45:21,360 --> 00:45:25,320 hivyo mimi nitakupa guys labda tano kwa dakika sita ili aina ya wachangie 857 00:45:25,320 --> 00:45:27,478 na kuandika kazi hii nje. 858 00:45:27,478 --> 00:45:29,710 >> Watazamaji: Hatuna akaunti kwa [inaudible], 859 00:45:29,710 --> 00:45:30,200 hatuna kutumia integer? 860 00:45:30,200 --> 00:45:31,241 >> PROFESA: Hapana, huna. 861 00:45:31,241 --> 00:48:05,847 862 00:48:05,847 --> 00:48:06,930 Mimi nitakupa guys ladha. 863 00:48:06,930 --> 00:48:12,325 Kitanzi wakati wanaweza kuwa muhimu sana hapa. 864 00:48:12,325 --> 00:48:12,825 Naam. 865 00:48:12,825 --> 00:48:44,995 866 00:48:44,995 --> 00:48:45,495 Hapa ni 867 00:48:45,495 --> 00:48:45,995 pipi. 868 00:48:45,995 --> 00:48:49,980 869 00:48:49,980 --> 00:48:53,410 Pipi pia inapatikana kwa jaribio, nadhani. 870 00:48:53,410 --> 00:48:55,315 Hivyo nyie itakuwa wote sugared hadi kesho. 871 00:48:55,315 --> 00:49:01,110 872 00:49:01,110 --> 00:49:02,962 Je, I-- wewe got it. 873 00:49:02,962 --> 00:49:03,718 >> Watazamaji: Sawa. 874 00:49:03,718 --> 00:49:04,384 PROFESA: Naam. 875 00:49:04,384 --> 00:49:10,550 876 00:49:10,550 --> 00:49:11,870 >> Labda sekunde 30 zaidi au hivyo. 877 00:49:11,870 --> 00:50:02,220 878 00:50:02,220 --> 00:50:07,340 >> Haki wote, kama wewe ni si kosa, hakuna wasiwasi. 879 00:50:07,340 --> 00:50:08,810 Tutaweza hoja kwa njia hii pamoja. 880 00:50:08,810 --> 00:50:09,310 SAWA. 881 00:50:09,310 --> 00:50:13,800 Hivyo nina kwenda tu mpangilio muundo wa msingi kwa kazi hii hapa. 882 00:50:13,800 --> 00:50:17,255 Int strlen. 883 00:50:17,255 --> 00:50:20,040 884 00:50:20,040 --> 00:50:23,460 Kwanza, haina mtu yeyote nataka kuwaambia mimi nini kwamba int kunaashiria? 885 00:50:23,460 --> 00:50:25,160 Tunahitaji kuwa na katika kazi hii. 886 00:50:25,160 --> 00:50:26,709 >> Watazamaji: Strlen [inaudible]. 887 00:50:26,709 --> 00:50:27,500 PROFESA: Hasa. 888 00:50:27,500 --> 00:50:31,140 Hivyo chochote kinachotokea katika hapa, tunahitaji kurudi integer. 889 00:50:31,140 --> 00:50:36,367 Na kama maalum katika spec, tunataka return-- 890 00:50:36,367 --> 00:50:37,700 Kwenda kwa hayo guys, tu kuendelea. 891 00:50:37,700 --> 00:50:40,480 Ni wote nzuri. 892 00:50:40,480 --> 00:50:42,960 Kula yote hivyo sina kuchukua ni nyuma, kwa kweli. 893 00:50:42,960 --> 00:50:46,022 894 00:50:46,022 --> 00:50:48,855 Int tu kunaashiria kwamba wewe ni kwenda kuwa kurudi integer. 895 00:50:48,855 --> 00:50:55,350 896 00:50:55,350 --> 00:50:57,106 >> Ni hii nyota Char s nini? 897 00:50:57,106 --> 00:50:58,640 Hiyo ina maana gani? 898 00:50:58,640 --> 00:51:00,879 >> Watazamaji: Kama, nini kuwa pembejeo katika. 899 00:51:00,879 --> 00:51:01,670 PROFESA: Hasa. 900 00:51:01,670 --> 00:51:04,142 Na kile ambacho ni karibu kitu kimoja kama Char nyota? 901 00:51:04,142 --> 00:51:04,850 Watazamaji: Kamba? 902 00:51:04,850 --> 00:51:05,641 PROFESA: Hasa. 903 00:51:05,641 --> 00:51:09,080 Basi wote sisi ni kufanya ni kutoa hii pointer kamba. 904 00:51:09,080 --> 00:51:09,580 SAWA. 905 00:51:09,580 --> 00:51:12,860 906 00:51:12,860 --> 00:51:13,360 Baridi. 907 00:51:13,360 --> 00:51:16,650 >> Pia, usisahau, kama sisi kusahau kukupa mabano haya, 908 00:51:16,650 --> 00:51:18,330 usisahau kuandika nao mwenyewe. 909 00:51:18,330 --> 00:51:20,720 Kwa sababu kinadharia, kanuni yako ni sahihi kama wewe kusahau kuandika yao. 910 00:51:20,720 --> 00:51:21,803 Daima tu makini. 911 00:51:21,803 --> 00:51:23,750 Kama, mambo kidogo kwamba huna taarifa 912 00:51:23,750 --> 00:51:26,917 wakati wewe ni programu juu ya mbali, kwa sababu mbali yako anafanya hivyo kwa ajili yenu? 913 00:51:26,917 --> 00:51:28,624 Usisahau wakati wewe ni kuandika kwa mkono. 914 00:51:28,624 --> 00:51:29,170 Yeah? 915 00:51:29,170 --> 00:51:30,954 >> Watazamaji: Lakini jinsi sahihi? 916 00:51:30,954 --> 00:51:33,190 Kama, tunapata tatizo vibaya nzima? 917 00:51:33,190 --> 00:51:34,190 >> PROFESA: Hapana, hapana. 918 00:51:34,190 --> 00:51:34,860 Msiwe na wasiwasi. 919 00:51:34,860 --> 00:51:39,270 Ni kweli kinadharia iwezekanavyo kwa ajili ya kupata pointi kamili juu ya swali 920 00:51:39,270 --> 00:51:41,980 hata kama kanuni yako mapenzi kamwe kukimbia katika maisha halisi. 921 00:51:41,980 --> 00:51:46,052 Mimi zinaonyesha huna kujaribu kufanya kutokea. 922 00:51:46,052 --> 00:51:48,260 Kwa mfano, kama kama kila kitu hiyo ni hapa ni haki, 923 00:51:48,260 --> 00:51:51,850 lakini wewe kusahau matumbo au mabano, kificho wako si kweli kuendesha. 924 00:51:51,850 --> 00:51:53,740 Lakini tunaweza kuwa na huruma. 925 00:51:53,740 --> 00:51:54,394 >> Yeah? 926 00:51:54,394 --> 00:51:56,050 >> Watazamaji: Je, una kutoa maoni juu ya hati zetu? 927 00:51:56,050 --> 00:51:57,758 >> PROFESA: Hapana, hapana, hapana wasiwasi juu ya hilo. 928 00:51:57,758 --> 00:51:58,440 Hakuna maoni. 929 00:51:58,440 --> 00:51:59,400 Mtindo lazima kuwa nzuri. 930 00:51:59,400 --> 00:52:01,470 Kama, si Smush kila kitu kwenye mstari mmoja. 931 00:52:01,470 --> 00:52:04,580 Hatutakuwa na furaha na wewe kama wewe kufanya hivyo. 932 00:52:04,580 --> 00:52:07,250 >> Je, mtu yeyote wanataka nipe mstari wa kwanza? 933 00:52:07,250 --> 00:52:08,633 Ladha, ni rahisi sana. 934 00:52:08,633 --> 00:52:09,320 >> Yeah? 935 00:52:09,320 --> 00:52:11,920 >> Watazamaji: Int, n sawa na sifuri. 936 00:52:11,920 --> 00:52:13,734 Tu kuanzisha kukabiliana. 937 00:52:13,734 --> 00:52:15,900 PROFESA: Hivyo tunataka baadhi aina ya kukabiliana, sawa? 938 00:52:15,900 --> 00:52:19,780 Mimi tu kwenda kwa jina hilo "kuhesabu" kwa ajili ya readability. 939 00:52:19,780 --> 00:52:21,265 Je, tunataka kuweka kwa sawa? 940 00:52:21,265 --> 00:52:21,890 >> Watazamaji: sifuri. 941 00:52:21,890 --> 00:52:23,840 PROFESA: Yep. 942 00:52:23,840 --> 00:52:24,340 Semicolon. 943 00:52:24,340 --> 00:52:26,250 Ni pia weird sana kuchora semicolons. 944 00:52:26,250 --> 00:52:28,870 Tu mazoezi ya kufanya hivyo. 945 00:52:28,870 --> 00:52:31,990 >> Hivyo tunataka kwanza na kukabiliana ya aina int. 946 00:52:31,990 --> 00:52:35,360 Kwa sababu tunataka kuhesabu hadi jinsi wahusika wengi au barua ni 947 00:52:35,360 --> 00:52:36,780 katika kamba hii, sawa? 948 00:52:36,780 --> 00:52:38,330 Rahisi sana hatua ya kwanza. 949 00:52:38,330 --> 00:52:42,140 >> OK, labda kidogo ngumu zaidi sasa, jinsi ni sisi kwenda kufanya hivyo? 950 00:52:42,140 --> 00:52:45,400 Je, mtu yeyote wanataka nipe mstari wa kanuni 951 00:52:45,400 --> 00:52:48,450 ambazo zinaweza kuwa na uwezo wa kusaidia kitanzi kupitia chochote hii ni? 952 00:52:48,450 --> 00:52:54,540 953 00:52:54,540 --> 00:52:56,900 >> Naam, jasiri nafsi katika nyuma? 954 00:52:56,900 --> 00:53:06,832 >> Watazamaji: sawa, hivyo wakati hatua Stars, yeah, nyota wa s, 955 00:53:06,832 --> 00:53:09,465 si sawa na sifuri, basi kufanya kitu? 956 00:53:09,465 --> 00:53:11,090 PROFESA: Hiyo ni kweli, kweli karibu. 957 00:53:11,090 --> 00:53:11,835 Kweli karibu. 958 00:53:11,835 --> 00:53:13,710 Hivyo nina kwenda kushughulikia mambo mawili na kwamba. 959 00:53:13,710 --> 00:53:18,240 Awali ya yote, siyo hasa sifuri. 960 00:53:18,240 --> 00:53:20,110 Ni nini? 961 00:53:20,110 --> 00:53:22,550 Ni null Terminator, ambayo ni backslash sifuri. 962 00:53:22,550 --> 00:53:24,960 Hivyo wao ni tofauti katika suala la jinsi wao ni kuhifadhiwa. 963 00:53:24,960 --> 00:53:26,270 Hivyo wewe ni kweli karibu. 964 00:53:26,270 --> 00:53:30,330 >> Na pili, hatutaki kwa hoja tu pointer. 965 00:53:30,330 --> 00:53:32,320 Tunataka kweli kupata maadili, haki? 966 00:53:32,320 --> 00:53:34,050 Na hivyo ni jinsi gani sisi kufanya hivyo? 967 00:53:34,050 --> 00:53:34,550 Rahisi sana. 968 00:53:34,550 --> 00:53:36,841 Sidhani kuhusu kuyatumia, sidhani kuhusu kumbukumbu. 969 00:53:36,841 --> 00:53:38,525 Kurudi nyuma na wiki mbili bila shaka hii. 970 00:53:38,525 --> 00:53:39,555 >> Watazamaji: [inaudible]. 971 00:53:39,555 --> 00:53:40,680 PROFESA: Kama ya, kumbuka? 972 00:53:40,680 --> 00:53:41,400 Masharti ni nini? 973 00:53:41,400 --> 00:53:42,650 Jinsi ndio kuhifadhiwa katika kumbukumbu? 974 00:53:42,650 --> 00:53:43,300 >> Watazamaji: Wao ni kukulia. 975 00:53:43,300 --> 00:53:43,810 >> PROFESA: Wao ni kukulia. 976 00:53:43,810 --> 00:53:45,550 Hivyo ni jinsi gani sisi kupata kila tabia ndani? 977 00:53:45,550 --> 00:53:46,466 >> Watazamaji: [inaudible]. 978 00:53:46,466 --> 00:53:47,530 PROFESA: Hasa. 979 00:53:47,530 --> 00:53:53,195 Hivyo while-- yale yanayoendelea ndani ya hapa? 980 00:53:53,195 --> 00:53:54,940 S ya - 981 00:53:54,940 --> 00:53:55,920 >> Watazamaji: I. 982 00:53:55,920 --> 00:53:58,216 >> PROFESA: Oh, i haipo, gani? 983 00:53:58,216 --> 00:53:59,620 >> Watazamaji: Oh, kuhesabu? 984 00:53:59,620 --> 00:54:01,640 >> PROFESA: Tunaweza tu kutumia kuhesabu, hawawezi sisi? 985 00:54:01,640 --> 00:54:03,050 >> Watazamaji: Samahani, mimi kuitwa ni i. 986 00:54:03,050 --> 00:54:04,341 >> PROFESA: Yeah, ni wote nzuri. 987 00:54:04,341 --> 00:54:06,710 988 00:54:06,710 --> 00:54:10,760 Tuna kutofautiana hapa hiyo ni tayari imetangazwa kama kukabiliana yetu. 989 00:54:10,760 --> 00:54:13,650 Hivyo kwa nini sio sisi tu kutumia kwamba hoja kwa njia ya kitanzi wakati? 990 00:54:13,650 --> 00:54:15,230 Je, hiyo mantiki? 991 00:54:15,230 --> 00:54:20,864 >> Hivyo wakati s ya count-- haina mtu yeyote wanataka kunipa kile kinachotokea baada ya hapa? 992 00:54:20,864 --> 00:54:22,030 Watazamaji: Ni haina sawa. 993 00:54:22,030 --> 00:54:23,405 PROFESA: Je, si sawa, sawa? 994 00:54:23,405 --> 00:54:26,200 Ni bang sawa, Moderators kumweka sawa, 995 00:54:26,200 --> 00:54:28,500 chochote guys wanataka kuiita haina equal-- 996 00:54:28,500 --> 00:54:29,496 >> Watazamaji: [inaudible]. 997 00:54:29,496 --> 00:54:30,990 >> PROFESA: Naam. 998 00:54:30,990 --> 00:54:37,110 Kumbuka moja kunukuu ni kwa Char, quotes mbili ni kwa kamba. 999 00:54:37,110 --> 00:54:38,630 Kuwa makini wakati kutumia yao. 1000 00:54:38,630 --> 00:54:42,430 Hivyo wakati sisi ni kutafuta njia ya safu, tabia mwisho, 1001 00:54:42,430 --> 00:54:46,420 tunajua hatutaki kuwa ni backslash sifuri. 1002 00:54:46,420 --> 00:54:47,340 >> Hivyo wakati. 1003 00:54:47,340 --> 00:54:48,840 Sisi si mwisho wa kamba. 1004 00:54:48,840 --> 00:54:52,335 Je, tunataka kufanya ndani? 1005 00:54:52,335 --> 00:54:55,269 >> Watazamaji: Tunataka kuongeza kukabiliana hivyo ni makosa pamoja pamoja? 1006 00:54:55,269 --> 00:54:56,060 PROFESA: Hasa. 1007 00:54:56,060 --> 00:55:03,064 Hivyo hapa sisi ni kwenda kufanya kuhesabu, kuhesabu pamoja pamoja. 1008 00:55:03,064 --> 00:55:03,980 Kukosa moja zaidi line. 1009 00:55:03,980 --> 00:55:05,090 Tuko karibu na hapo. 1010 00:55:05,090 --> 00:55:07,398 Je, ni sisi kusahau kufanya nini? 1011 00:55:07,398 --> 00:55:08,770 >> Watazamaji: Kurudi sifuri? 1012 00:55:08,770 --> 00:55:10,820 >> PROFESA: Unataka kurudi sifuri? 1013 00:55:10,820 --> 00:55:12,962 >> Watazamaji: Hakuna, kurudi kwa strlen. 1014 00:55:12,962 --> 00:55:13,511 Kusubiri. 1015 00:55:13,511 --> 00:55:14,760 PROFESA: Ni ni kuhifadhiwa katika? 1016 00:55:14,760 --> 00:55:15,090 Watazamaji: Hesabu. 1017 00:55:15,090 --> 00:55:15,589 Kuhesabu. 1018 00:55:15,589 --> 00:55:17,150 PROFESA: Hasa. 1019 00:55:17,150 --> 00:55:20,760 Hivyo hapa sisi ni kwenda na kurudi kuhesabu. 1020 00:55:20,760 --> 00:55:23,450 1021 00:55:23,450 --> 00:55:25,380 >> Kwa sababu gani tuko kufanya hapa ultimately-- 1022 00:55:25,380 --> 00:55:29,780 tuna kukabiliana kutofautiana hiyo ni kwenda increment kupitia kamba yetu. 1023 00:55:29,780 --> 00:55:33,050 Tunakwenda kuendelea, kuweka kwenda, kwa kuzunguka katika kitanzi hii. 1024 00:55:33,050 --> 00:55:37,700 Na wakati sisi siyo tarehe ya mwisho ya hii kamba, ambayo ni null Terminator. 1025 00:55:37,700 --> 00:55:40,410 >> Na kila wakati sisi kwenda kwa njia ya hivyo, sisi ni kuongeza ili kukabiliana na yetu. 1026 00:55:40,410 --> 00:55:42,640 Na tunakwenda zaidi pamoja katika safu hii. 1027 00:55:42,640 --> 00:55:44,880 Na mwisho, mara moja sisi kugonga null Terminator, 1028 00:55:44,880 --> 00:55:48,469 tunajua, loo, tunaweza kuvunja, kurudi kuhesabu. 1029 00:55:48,469 --> 00:55:49,260 Tuna strlen yetu. 1030 00:55:49,260 --> 00:55:52,280 1031 00:55:52,280 --> 00:55:56,400 >> Je, kila mtu kupata jinsi hii ilikuwa kutekelezwa? 1032 00:55:56,400 --> 00:55:58,830 Wakati loops-- Najua kuwa hatuna amefanya sana pamoja nao, 1033 00:55:58,830 --> 00:56:01,240 lakini wao ni kawaida sana, muhimu sana kama 1034 00:56:01,240 --> 00:56:05,390 sijui nini wewe kuacha hali lazima ina kuwa. 1035 00:56:05,390 --> 00:56:06,220 >> Swali? 1036 00:56:06,220 --> 00:56:10,080 >> Watazamaji: Je, sisi kuandika null kwa masharti wakati? 1037 00:56:10,080 --> 00:56:10,940 >> PROFESA: Wakati? 1038 00:56:10,940 --> 00:56:15,304 Yeah, hivyo katika tatizo hili nilikuwa wewe guys kudhani kuwa s haitakuwa null. 1039 00:56:15,304 --> 00:56:17,220 Kwa sababu kumbuka, kinadharia, ikiwa niliokupa 1040 00:56:17,220 --> 00:56:21,180 pointer kwamba alikuwa pia kikubwa cha kumbukumbu, ingekuwa kukupa null, haki? 1041 00:56:21,180 --> 00:56:23,770 Hilo ndilo uendeshaji mfumo atafanya. 1042 00:56:23,770 --> 00:56:26,960 >> Hivyo kama mimi Sikuwaambieni kwa kudhani s itakuwa batili, unahitaji kuangalia. 1043 00:56:26,960 --> 00:56:32,050 Hivyo hapa up, ungependa kufanya kama sawa sawa na null, kurudi moja. 1044 00:56:32,050 --> 00:56:33,028 Kitu kama hicho. 1045 00:56:33,028 --> 00:56:34,153 Watazamaji: [inaudible] sifuri. 1046 00:56:34,153 --> 00:56:37,287 1047 00:56:37,287 --> 00:56:39,370 PROFESA: Sawa, mimi nitakuambia wewe kwa nini hatuwezi kufanya hivyo. 1048 00:56:39,370 --> 00:56:43,357 Kwa sababu kumbuka katika kumbukumbu, haki, hapa. 1049 00:56:43,357 --> 00:56:43,940 Tutaweza kwenda hapa. 1050 00:56:43,940 --> 00:56:49,940 1051 00:56:49,940 --> 00:56:54,090 >> Nimepata vitalu kubwa ya kumbukumbu zote na grids 1052 00:56:54,090 --> 00:56:56,680 kwamba duka maadili tofauti, sawa? 1053 00:56:56,680 --> 00:57:00,110 Na hivyo kamba zote is-- kwa mfano, kama sisi ni pembejeo hodi, 1054 00:57:00,110 --> 00:57:05,490 itakuwa H-E-L-L-O sifuri backslash, sawa? 1055 00:57:05,490 --> 00:57:09,570 Na kisha ambaye anajua, kama random mambo ambayo ni katika hapa baada yake. 1056 00:57:09,570 --> 00:57:11,220 >> Sisi si kweli kujua nini huko. 1057 00:57:11,220 --> 00:57:13,350 Na hivyo kama ungekuwa kufanya badala ya backslash sifuri, 1058 00:57:13,350 --> 00:57:15,590 null, inaweza kuwa null. 1059 00:57:15,590 --> 00:57:17,680 Kwa sababu tu inaweza kuwa na maana baadhi ya mambo mengine random 1060 00:57:17,680 --> 00:57:19,270 ambayo si mali katika kamba yako. 1061 00:57:19,270 --> 00:57:23,219 Na hivyo kwa njia hiyo sisi daima kujua kwamba kamba mwisho ni pamoja na backslash sifuri. 1062 00:57:23,219 --> 00:57:25,760 Na hivyo ndiyo siku zote jinsi sisi kuangalia kuona mwisho wa kamba. 1063 00:57:25,760 --> 00:57:30,820 >> Batili, njia kwamba wote ni kama una pointer haupo, kwanza ya yote, 1064 00:57:30,820 --> 00:57:36,160 au kama kumbukumbu yako ni tu kubwa kwamba huwezi kurudi, basi ni d kuwa null. 1065 00:57:36,160 --> 00:57:40,150 Hivyo kuwa makini sana wakati kutofautisha Tofauti kati null 1066 00:57:40,150 --> 00:57:42,130 na backslash sifuri. 1067 00:57:42,130 --> 00:57:43,670 Naam. 1068 00:57:43,670 --> 00:57:46,886 >> Kila mtu sawa na hili? 1069 00:57:46,886 --> 00:57:48,150 SAWA. 1070 00:57:48,150 --> 00:57:50,440 >> Kwa hiyo mimi alikuwa nyie kuandika strlen. 1071 00:57:50,440 --> 00:57:53,790 Kuchukuliwa kwa tungeweza pia kuuliza wewe kuandika nje kwa mimi, kumbuka kwamba "Atwoa" 1072 00:57:53,790 --> 00:57:55,400 au chochote nyie unataka simu yake? 1073 00:57:55,400 --> 00:57:58,010 Hiyo kazi katika Vigenere na Kaisari, kwamba 1074 00:57:58,010 --> 00:58:00,900 waongofu Ascii thamani ya integer? 1075 00:58:00,900 --> 00:58:04,360 Hiyo pia ina kuja juu ya siku za nyuma Quizzes wa majukumu tumekuwa aliuliza wewe kuandika. 1076 00:58:04,360 --> 00:58:08,280 >> Pretty much kazi yoyote kwamba umetumia na ni 1077 00:58:08,280 --> 00:58:11,660 rahisi sana kuandika mwenyewe, sensorer kama ni ya chini, 1078 00:58:11,660 --> 00:58:14,620 ni juu, ili kupunguza, kwa juu. 1079 00:58:14,620 --> 00:58:17,964 Kazi hiyo inaweza kubadilisha kamba kutoka lowercase kwa uppercase. 1080 00:58:17,964 --> 00:58:19,380 Sote tunajua jinsi ya kufanya hivyo, sawa? 1081 00:58:19,380 --> 00:58:21,100 Ni rahisi sana. 1082 00:58:21,100 --> 00:58:24,770 Nataka tu kuhakikisha kuwa wewe can-- ni mawazo mchakato huo. 1083 00:58:24,770 --> 00:58:26,940 Wewe tu iterate kupitia na kurejea mambo. 1084 00:58:26,940 --> 00:58:30,190 Wewe ama hesabu au wakati kurejea mambo tofauti. 1085 00:58:30,190 --> 00:58:32,280 >> Napenda suggest-- mimi sijui kama tunakwenda 1086 00:58:32,280 --> 00:58:39,080 kuuliza kukariri kile mtaji au mji mkuu Z, au lowercase A au lowercase 1087 00:58:39,080 --> 00:58:42,640 z ni katika Ascii, lakini napenda kupendekeza labda kuandika kwamba chini katika kesi 1088 00:58:42,640 --> 00:58:44,124 tunafanya. 1089 00:58:44,124 --> 00:58:45,540 Hivyo tu nyie na kumbukumbu. 1090 00:58:45,540 --> 00:58:47,180 Kama uppercase A ni, nini, 197? 1091 00:58:47,180 --> 00:58:51,320 Na kisha lowercase ni kama 50 na kitu. 1092 00:58:51,320 --> 00:58:52,492 65, yeah, kuna kwenda. 1093 00:58:52,492 --> 00:58:54,950 Hivyo tu pretty much kujua tofauti kati yao ni 32. 1094 00:58:54,950 --> 00:58:57,670 Hiyo ni pretty muhimu. 1095 00:58:57,670 --> 00:58:58,170 Naam. 1096 00:58:58,170 --> 00:59:01,445 Mimi ni nzuri juu ya hili? 1097 00:59:01,445 --> 00:59:01,945 SAWA. 1098 00:59:01,945 --> 00:59:03,109 >> Watazamaji: Tunaweza kinadharia kuandika baadhi 1099 00:59:03,109 --> 00:59:04,410 ya hizi chini pamoja juu ya little-- yetu 1100 00:59:04,410 --> 00:59:07,035 >> PROFESA: Wewe kinadharia inaweza tu nakala kazi chini. 1101 00:59:07,035 --> 00:59:08,482 Hiyo ni kweli. 1102 00:59:08,482 --> 00:59:11,080 >> Watazamaji: Si [inaudible]. 1103 00:59:11,080 --> 00:59:12,720 >> PROFESA: You guys kuwa na karatasi. 1104 00:59:12,720 --> 00:59:14,194 Nyie na karatasi kumbuka. 1105 00:59:14,194 --> 00:59:14,860 Unaweza aina hiyo. 1106 00:59:14,860 --> 00:59:15,490 Unaweza kuandika hayo. 1107 00:59:15,490 --> 00:59:17,031 Unaweza kufanya chochote unataka na hayo. 1108 00:59:17,031 --> 00:59:18,530 Naam. 1109 00:59:18,530 --> 00:59:21,406 Hivyo kinadharia, ikiwa unataka, kwenda kwa. 1110 00:59:21,406 --> 00:59:23,338 >> Watazamaji: [inaudible] lakini sisi si kweli 1111 00:59:23,338 --> 00:59:25,994 lazima haja ya kukumbuka thamani, tunaweza tu 1112 00:59:25,994 --> 00:59:28,914 kutumia juu au kwa kazi chini, sawa? 1113 00:59:28,914 --> 00:59:29,580 PROFESA: Naam. 1114 00:59:29,580 --> 00:59:32,740 Lakini kama tuliyowapa swali inayosema kuandika kwa juu, 1115 00:59:32,740 --> 00:59:34,350 basi ingekuwa haja ya kuandika. 1116 00:59:34,350 --> 00:59:38,150 Hivyo wewe guys unaweza kudhani kuwa wewe guys kupata kazi zote, 1117 00:59:38,150 --> 00:59:41,523 lakini kama unataka kutumia kwa juu au kwa chini, je, pia una kufanya? 1118 00:59:41,523 --> 00:59:43,840 >> Watazamaji: [inaudible] kutumia CS50 [inaudible] 1119 00:59:43,840 --> 00:59:44,840 >> PROFESA: Je, ni CS50.h? 1120 00:59:44,840 --> 00:59:47,320 1121 00:59:47,320 --> 00:59:48,310 Kuwa makini huko. 1122 00:59:48,310 --> 00:59:50,640 >> Hivyo kwa juu, kupunguza, ni juu, ni ya chini, 1123 00:59:50,640 --> 00:59:52,990 kazi ambazo zinahusisha kamba kudanganywa ni 1124 00:59:52,990 --> 00:59:55,490 yote ndani ama Ascii au ndani ya maktaba math 1125 00:59:55,490 --> 00:59:57,350 au ndani ya maktaba kamba. 1126 00:59:57,350 --> 01:00:00,290 Hivyo kama wewe guys kutumia wale kazi, kuwa makini na kukumbuka 1127 01:00:00,290 --> 01:00:01,451 ni pamoja na mpira wa kichwa hicho. 1128 01:00:01,451 --> 01:00:03,950 Hivyo labda pia jambo unataka pamoja katika karatasi yako, 1129 01:00:03,950 --> 01:00:04,892 kile ni kichwa? 1130 01:00:04,892 --> 01:00:06,600 Ni maktaba nini tumekuwa kutumia? 1131 01:00:06,600 --> 01:00:08,550 Nini kazi ni ndani ya maktaba hizo? 1132 01:00:08,550 --> 01:00:09,230 Ni muhimu. 1133 01:00:09,230 --> 01:00:10,420 >> Yeah? 1134 01:00:10,420 --> 01:00:12,570 >> Watazamaji: Je sisi tu askari nje na kufanya alama 1135 01:00:12,570 --> 01:00:14,955 kupitia kabisa kila barua tumekuwa milele 1136 01:00:14,955 --> 01:00:17,340 kuonekana kama juu ya maswali yote? 1137 01:00:17,340 --> 01:00:18,320 >> PROFESA: Wewe naweza. 1138 01:00:18,320 --> 01:00:20,361 Sijui jinsi ya furaha tunakwenda kuwa na daraja 1139 01:00:20,361 --> 01:00:25,090 Jaribio kwamba wakati kila kipande cha kanuni ni mara mbili kwa muda mrefu kama kuna haja kuwa. 1140 01:00:25,090 --> 01:00:27,200 Sijui, tupate kuchukua mbali hatua kwa mtindo. 1141 01:00:27,200 --> 01:00:28,790 Lakini kinadharia yako kificho itakuwa haki. 1142 01:00:28,790 --> 01:00:30,915 Nyie naweza askari nje na tu ni pamoja na kila kitu. 1143 01:00:30,915 --> 01:00:32,044 Hiyo ni sawa pia, yeah. 1144 01:00:32,044 --> 01:00:32,960 Watazamaji: [inaudible]. 1145 01:00:32,960 --> 01:00:33,270 PROFESA: Naam. 1146 01:00:33,270 --> 01:00:34,900 Ningependa kupendekeza si kufanya hivyo ingawa. 1147 01:00:34,900 --> 01:00:35,505 Naam. 1148 01:00:35,505 --> 01:00:36,130 Watazamaji: Moto. 1149 01:00:36,130 --> 01:00:36,620 PROFESA: Swali Mwema. 1150 01:00:36,620 --> 01:00:37,480 Watazamaji: Hivyo, mazingira ya kesi mbaya. 1151 01:00:37,480 --> 01:00:38,563 PROFESA: hali mbaya zaidi. 1152 01:00:38,563 --> 01:00:40,350 Kama kabisa kusahau, unaweza kufanya hivyo. 1153 01:00:40,350 --> 01:00:40,850 Naam. 1154 01:00:40,850 --> 01:00:43,870 1155 01:00:43,870 --> 01:00:45,400 >> Yep, kanuni ni haki pale. 1156 01:00:45,400 --> 01:00:49,176 Nilikuwa n badala ya kuhesabu lakini, wewe Unajua, chochote ikifungwa mashua yako. 1157 01:00:49,176 --> 01:00:51,092 Watazamaji: Ngoja, hivyo sisi bila kuwa na alama 1158 01:00:51,092 --> 01:00:53,460 pamoja na sababu tuko kuanzia saa int? 1159 01:00:53,460 --> 01:00:56,150 1160 01:00:56,150 --> 01:00:59,924 >> PROFESA: Yeah, I just kudhani kuwa sisi waliombwa kuandika kazi. 1161 01:00:59,924 --> 01:01:02,340 Kama alitaka kuwa salama, wewe inaweza pengine kuiweka huko. 1162 01:01:02,340 --> 01:01:05,650 Lakini mimi tu haikujali, yeah. 1163 01:01:05,650 --> 01:01:09,919 >> Mimi wala hata kujua kama wewe haja maktaba yoyote kwa hili. 1164 01:01:09,919 --> 01:01:12,710 Kwa sababu wewe si kweli uchapishaji nje chochote au kitu chochote, sawa? 1165 01:01:12,710 --> 01:01:16,500 1166 01:01:16,500 --> 01:01:19,568 Naam, mimi sijui kama unahitaji maktaba. 1167 01:01:19,568 --> 01:01:22,400 >> SAWA. 1168 01:01:22,400 --> 01:01:26,020 Hii pia ni kidogo zaidi pamoja mistari ya kumbukumbu kudanganywa. 1169 01:01:26,020 --> 01:01:27,400 Aina hii ya kidogo Tricky. 1170 01:01:27,400 --> 01:01:28,960 Fikiria kuhusu hili. 1171 01:01:28,960 --> 01:01:30,580 Una kazi kuitwa func. 1172 01:01:30,580 --> 01:01:33,570 Mimi nilikuwa na jina lake ni chochote, lakini mimi kuchagua jina hilo func. 1173 01:01:33,570 --> 01:01:36,000 Mimi kuwa ni juu kuu wangu. 1174 01:01:36,000 --> 01:01:39,790 Kumbuka, unataka kuwa na kazi baada kuu yako, 1175 01:01:39,790 --> 01:01:42,370 unataka kuhakikisha pamoja na mfano wa juu. 1176 01:01:42,370 --> 01:01:45,750 >> Lakini katika kesi hii ilikuwa ni ya muda mfupi kwamba nilihisi kuwa mimi naweza tu 1177 01:01:45,750 --> 01:01:47,260 pamoja na hayo atop kuu. 1178 01:01:47,260 --> 01:01:51,170 Mimi hakuwa na haja ya kuwa na mfano, kwa sababu ni tayari imeandikwa juu. 1179 01:01:51,170 --> 01:01:55,430 Basi wote mimi nina kufanya katika kazi yangu kuu ni kujenga integer x sawa 10. 1180 01:01:55,430 --> 01:02:00,490 Mimi nina wito func yangu kazi, na kisha kuchapisha up kitu. 1181 01:02:00,490 --> 01:02:02,840 >> Na kisha hiyo ni kweli nini func ni kufanya. 1182 01:02:02,840 --> 01:02:04,340 Nyie nataka kufikiri kwa njia hii. 1183 01:02:04,340 --> 01:02:05,423 Kwa sababu ni kidogo suala gumu. 1184 01:02:05,423 --> 01:02:07,220 Ni sana, gumu sana, kwa kweli. 1185 01:02:07,220 --> 01:02:09,549 Kufikiri kwa nini hii Mpango itakuwa outputting. 1186 01:02:09,549 --> 01:02:10,840 Mimi nitakupa guys dakika mbili. 1187 01:02:10,840 --> 01:03:36,660 1188 01:03:36,660 --> 01:03:37,891 >> Majadiliano nzuri? 1189 01:03:37,891 --> 01:03:38,853 >> Watazamaji: Naam. 1190 01:03:38,853 --> 01:03:39,815 >> PROFESA: Naam. 1191 01:03:39,815 --> 01:03:42,220 Haki wote, hivyo hii ni gumu kwa sababu. 1192 01:03:42,220 --> 01:03:44,845 Na hii ni kwa nini nilitaka kuleta huu kwa mawazo ya kila mtu. 1193 01:03:44,845 --> 01:03:47,870 1194 01:03:47,870 --> 01:03:51,147 Je, mtu yeyote wanataka kunipa maoni, jaribio? 1195 01:03:51,147 --> 01:03:52,230 Kitu gani hii magazeti nje? 1196 01:03:52,230 --> 01:03:53,930 Kabisa faini kama wewe ni sahihi. 1197 01:03:53,930 --> 01:03:55,619 Yeah? 1198 01:03:55,619 --> 01:03:59,483 >> Watazamaji: Nadhani ni 100 na kisha 10 juu ya mistari mbili tofauti. 1199 01:03:59,483 --> 01:04:00,940 >> PROFESA: Na 10? 1200 01:04:00,940 --> 01:04:03,154 Je, mtu yeyote kuwa na guesses nyingine yoyote? 1201 01:04:03,154 --> 01:04:04,150 Yeah? 1202 01:04:04,150 --> 01:04:09,040 >> Watazamaji: Labda tu kwa sababu 10 func si kurudi kitu chochote? 1203 01:04:09,040 --> 01:04:11,610 >> PROFESA: Sawa, hivyo sisi na nadhani namba moja 1204 01:04:11,610 --> 01:04:14,990 ni kwamba nadhani namba mbili ni tu kwenda magazeti nje 10. 1205 01:04:14,990 --> 01:04:17,623 Je, mtu yeyote kuwa na guesses nyingine yoyote? 1206 01:04:17,623 --> 01:04:19,654 SAWA. 1207 01:04:19,654 --> 01:04:21,070 Basi hebu kutembea kwa njia hii, sawa? 1208 01:04:21,070 --> 01:04:23,903 Wakati wowote kupata kipande cha kanuni, si tu kuangalia ni na kuwa kama, 1209 01:04:23,903 --> 01:04:25,060 ah, hiyo ni mambo sana! 1210 01:04:25,060 --> 01:04:26,460 Mimi hivyo kuchanganyikiwa! 1211 01:04:26,460 --> 01:04:28,220 Kama, utulivu mwenyewe chini. 1212 01:04:28,220 --> 01:04:31,602 Tu kujua kwamba unaweza tu kuangalia njia kificho mstari kwa mstari. 1213 01:04:31,602 --> 01:04:32,310 Hayo ni yote ni. 1214 01:04:32,310 --> 01:04:33,840 Ni kama kusoma kitabu. 1215 01:04:33,840 --> 01:04:38,000 >> Hivyo, pamoja na kazi yoyote, sisi daima kuanza saa kuu. 1216 01:04:38,000 --> 01:04:40,860 Hivyo sisi ni kwenda kwa kuanza saa int kuu utupu, 1217 01:04:40,860 --> 01:04:43,010 hata mpango huo tayari kukimbia chini, sawa? 1218 01:04:43,010 --> 01:04:45,070 Kuanza saa katika utupu kuu. 1219 01:04:45,070 --> 01:04:48,030 Int x ni sawa na 10. 1220 01:04:48,030 --> 01:04:50,400 >> Hivyo nina kwenda kwa kufuta hii. 1221 01:04:50,400 --> 01:04:55,179 1222 01:04:55,179 --> 01:04:58,470 Mimi nina kwenda kuteka kumbukumbu tu hivyo guys unaweza aina ya kuona nini kinatokea. 1223 01:04:58,470 --> 01:05:02,190 >> Kumbuka chini hapa tuna mkusanyiko wetu? 1224 01:05:02,190 --> 01:05:05,810 Hadi hapa tuna wetu chungu mahali fulani hapa. 1225 01:05:05,810 --> 01:05:07,470 Stack kukua, sawa? 1226 01:05:07,470 --> 01:05:10,150 Na ndani ya stack, una mains kazi kama vile 1227 01:05:10,150 --> 01:05:12,230 wote wa vigezo mains ndani. 1228 01:05:12,230 --> 01:05:14,310 >> Hivyo hapa, int x sawa 10. 1229 01:05:14,310 --> 01:05:17,670 Ndani ya kazi yetu kuu tuko kujenga variable kuitwa x. 1230 01:05:17,670 --> 01:05:20,590 Sisi ni kuweka kwamba sawa na 10. 1231 01:05:20,590 --> 01:05:24,200 Hapa nimepata baadhi x, na uko kuweka kwamba sawa na 10, kulia, 1232 01:05:24,200 --> 01:05:25,400 ndani ya kuu. 1233 01:05:25,400 --> 01:05:27,430 Kila mtu mwema? 1234 01:05:27,430 --> 01:05:28,070 >> Kazi. 1235 01:05:28,070 --> 01:05:30,330 Hivyo sasa, ndani ya kuu yetu kazi, sisi ni wito 1236 01:05:30,330 --> 01:05:31,810 kazi tumekuwa imeandikwa hapo juu. 1237 01:05:31,810 --> 01:05:34,550 Hivyo sisi ni sasa kuingia kazi ya pili. 1238 01:05:34,550 --> 01:05:40,120 Tunakwenda kuunda nyingine kutofautiana int x sawa 100. 1239 01:05:40,120 --> 01:05:42,410 Nini kinatokea hapa katika stack? 1240 01:05:42,410 --> 01:05:46,980 Nini kinatokea wakati wewe piga kazi ambayo inajenga vigezo mpya? 1241 01:05:46,980 --> 01:05:50,038 Nini kinatokea hapa katika stack? 1242 01:05:50,038 --> 01:05:52,134 >> Watazamaji: [inaudible] piles juu? 1243 01:05:52,134 --> 01:05:52,800 PROFESA: Naam. 1244 01:05:52,800 --> 01:05:54,050 Hivyo ni kweli inajenga nakala. 1245 01:05:54,050 --> 01:05:56,560 1246 01:05:56,560 --> 01:05:57,740 Na aina ya piles juu. 1247 01:05:57,740 --> 01:06:00,700 Fikiria stack-- mkusanyiko ya vitabu, mkusanyiko wa kitu chochote. 1248 01:06:00,700 --> 01:06:06,520 Piles juu, kwanza katika mwisho nje, mara ya mwisho katika, kwanza nje. 1249 01:06:06,520 --> 01:06:08,471 >> Hivyo ni kwenda kujenga x hapa. 1250 01:06:08,471 --> 01:06:12,080 1251 01:06:12,080 --> 01:06:14,450 >> Hiyo inaenda kuwa funcs zote vigezo. 1252 01:06:14,450 --> 01:06:14,950 Kubwa. 1253 01:06:14,950 --> 01:06:20,980 Hivyo basi, tuna mbili tofauti x kwamba kuwakilisha mambo mawili tofauti sana. 1254 01:06:20,980 --> 01:06:24,470 Kisha tunakwenda magazeti nje integer ya x. 1255 01:06:24,470 --> 01:06:26,430 Basi hebu magazeti 100, sawa? 1256 01:06:26,430 --> 01:06:29,389 Kwa sababu hapa ni 100. 1257 01:06:29,389 --> 01:06:31,680 Hivyo hiyo ni jambo la kwanza kwamba ni kwenda magazeti nje. 1258 01:06:31,680 --> 01:06:35,710 Kama hii anarudi kazi kitu, sasa kwamba kazi, kwamba mstari katika kuu 1259 01:06:35,710 --> 01:06:37,070 ni kosa. 1260 01:06:37,070 --> 01:06:39,160 Kila mtu mzuri na mimi hadi sasa? 1261 01:06:39,160 --> 01:06:43,034 >> Hivyo sisi ni sasa kupitia wawili kati ya mistari mitatu ya kazi yetu kuu. 1262 01:06:43,034 --> 01:06:44,450 Sasa tunakwenda mstari wa tatu. 1263 01:06:44,450 --> 01:06:46,350 Tunakwenda printf. 1264 01:06:46,350 --> 01:06:48,222 Ni hii x ndani ya kuu ni nini? 1265 01:06:48,222 --> 01:06:49,263 Je, hiyo kuwakilisha? 1266 01:06:49,263 --> 01:06:52,720 1267 01:06:52,720 --> 01:06:54,280 >> Nini thamani ya x sasa? 1268 01:06:54,280 --> 01:06:55,220 >> Watazamaji: 100. 1269 01:06:55,220 --> 01:06:56,799 >> PROFESA: Ni 100? 1270 01:06:56,799 --> 01:06:57,590 Watazamaji: Bado 10. 1271 01:06:57,590 --> 01:06:58,878 PROFESA: Bado 10. 1272 01:06:58,878 --> 01:07:00,870 Naam. 1273 01:07:00,870 --> 01:07:06,810 Kwa sababu kumbuka, ndani ya func yetu, x sawa 100. 1274 01:07:06,810 --> 01:07:09,690 Lakini kama sisi kurudi nyuma kwa kazi yetu kuu, 1275 01:07:09,690 --> 01:07:12,440 kwamba kutofautiana ni kuhifadhiwa katika mahali tofauti juu ya stack yetu. 1276 01:07:12,440 --> 01:07:16,250 >> Hivyo sasa tunahitaji kurudi nyuma na stack kuu, mains vigezo mitaa. 1277 01:07:16,250 --> 01:07:18,460 Na hapa x ni sawa na 10. 1278 01:07:18,460 --> 01:07:20,300 Na hivyo sisi ni kwenda magazeti nje 10. 1279 01:07:20,300 --> 01:07:22,530 >> Hivyo yeye alikuwa na haki kabisa. 1280 01:07:22,530 --> 01:07:25,053 Tunakwenda kuwa na pato la 100 na 10. 1281 01:07:25,053 --> 01:07:25,553 Yeah? 1282 01:07:25,553 --> 01:07:28,700 Watazamaji: Wakati wewe malloc, je, ni lundo au stack kwamba ni [inaudible]? 1283 01:07:28,700 --> 01:07:31,950 PROFESA: Wakati malloc, wewe ni kuchukua kumbukumbu kutoka lundo 1284 01:07:31,950 --> 01:07:32,830 na kugawa yake. 1285 01:07:32,830 --> 01:07:34,950 Hivyo kwamba huna kwa fujo na yoyote ya hii. 1286 01:07:34,950 --> 01:07:38,100 Kwa hiyo mimi nadhani takeaway kubwa hapa ni kitu kinachoitwa wigo. 1287 01:07:38,100 --> 01:07:39,650 >> Kwa wale ambao walikuwa katika mapitio kikao jana usiku, 1288 01:07:39,650 --> 01:07:41,080 sisi aliyesema ufupi juu ya jambo hili. 1289 01:07:41,080 --> 01:07:45,380 Wigo amefafanua jinsi na wakati vigezo yako kuwepo. 1290 01:07:45,380 --> 01:07:48,050 Au ndani ya kile muafaka kufanya vigezo yako kuwepo. 1291 01:07:48,050 --> 01:07:51,690 >> Pretty sana utawala wa kidole gumba kwa ujumla ni, variables-- yako kama wewe kujenga yao 1292 01:07:51,690 --> 01:07:56,660 ndani ya curly braces zipo tu ndani ya braces wale curly. 1293 01:07:56,660 --> 01:08:00,312 >> Hivyo kwa mfano katika kazi yetu ya func, unaweza kuona wale braces mbili. 1294 01:08:00,312 --> 01:08:02,020 Kama wewe ni kujenga chochote ndani yake, 1295 01:08:02,020 --> 01:08:06,500 nafasi ni yote wewe kufanya ni kujenga stack na kuhifadhi kwamba kuna. 1296 01:08:06,500 --> 01:08:07,430 Same kitu katika kuu. 1297 01:08:07,430 --> 01:08:09,950 Hiyo tu kuhifadhiwa ndani ya kuu. 1298 01:08:09,950 --> 01:08:13,560 >> Pia unataka kuwa mwangalifu sana hapa. 1299 01:08:13,560 --> 01:08:18,310 Kwa sababu ya wigo pia lends yenyewe kwa mifano mbalimbali. 1300 01:08:18,310 --> 01:08:25,950 Hivyo kwa mfano a kwa kitanzi, kwa int i sawa 0. 1301 01:08:25,950 --> 01:08:28,460 Mimi ni chini ya, sijui, 10. 1302 01:08:28,460 --> 01:08:32,111 Mimi pamoja na plus. 1303 01:08:32,111 --> 01:08:34,560 Na nimepata kificho ndani yake, sawa? 1304 01:08:34,560 --> 01:08:38,830 >> Wapi kutofautiana hii, i, kwa kweli tu zipo? 1305 01:08:38,830 --> 01:08:40,510 Tu ndani ya yako kwa kitanzi. 1306 01:08:40,510 --> 01:08:43,640 Hivyo I bet wengi wenu guys kuwa pengine ilipata hitilafu hii wakati 1307 01:08:43,640 --> 01:08:45,930 unafanya mipango katika psets yako. 1308 01:08:45,930 --> 01:08:49,990 Ni wangapi wenu guys wamejaribu kutumia i nje ya kwa kitanzi na alikuwa makosa? 1309 01:08:49,990 --> 01:08:53,310 Kama integers unreferenced au kitu kama hicho? 1310 01:08:53,310 --> 01:08:56,069 >> Sababu ni kwa nini kitu kinachotokea ni kwa sababu hapa uko 1311 01:08:56,069 --> 01:08:59,109 kujenga kitu ambacho tu ipo ndani ya yako kwa kitanzi. 1312 01:08:59,109 --> 01:09:01,972 Na kama wewe kujaribu kuitumia, i hana kweli zipo nje ya hiyo. 1313 01:09:01,972 --> 01:09:04,930 Hivyo kimsingi kompyuta wakisema, Mimi hawajui nini wewe kuzungumza juu. 1314 01:09:04,930 --> 01:09:08,689 Najua wote ni kwamba i alikuwa hapa, lakini sasa hakuna tena. 1315 01:09:08,689 --> 01:09:12,580 >> Hivyo kama ningekuwa kujenga kwa kitanzi ndani, sawa? 1316 01:09:12,580 --> 01:09:19,080 Na mimi nina kwenda kujenga mwingine, kama int j, na kuwa ni kufanya chochote. 1317 01:09:19,080 --> 01:09:23,689 Na una kificho ndani ya kuwa kitanzi, j tu ipo hapa. 1318 01:09:23,689 --> 01:09:26,029 Lakini hiyo pia ipo ndani ya i. 1319 01:09:26,029 --> 01:09:29,310 Na hivyo j ipo tu ndani ya hii kwa kitanzi, 1320 01:09:29,310 --> 01:09:33,850 ambapo i ipo katika jambo zima. 1321 01:09:33,850 --> 01:09:34,500 >> Kila mtu wazi? 1322 01:09:34,500 --> 01:09:37,416 Same kitu na kauli masharti kama unataka kujenga kitu chochote. 1323 01:09:37,416 --> 01:09:40,390 Same kitu na wakati tanzi kama unataka kujenga kitu chochote. 1324 01:09:40,390 --> 01:09:42,390 Hiyo ni kitu cha mwangalifu sana kuhusu. 1325 01:09:42,390 --> 01:09:45,681 Hivyo hii ilikuwa ni tatizo mzuri katika kuhisi kwamba alionyesha mambo mawili. 1326 01:09:45,681 --> 01:09:47,160 Ni alionyesha kwanza, wigo. 1327 01:09:47,160 --> 01:09:49,550 Na alionyesha pia mgao kumbukumbu. 1328 01:09:49,550 --> 01:09:54,130 Kwa sababu nyie anapaswa kujua kuwa kazi kukua zaidi katika stack. 1329 01:09:54,130 --> 01:09:56,710 Na kwamba wakati wewe piga kazi, wewe ni kujenga 1330 01:09:56,710 --> 01:09:59,060 kimsingi stack mpya wa kumbukumbu. 1331 01:09:59,060 --> 01:10:02,100 Hiyo ni tofauti sana na nini mains yako kumbukumbu ni. 1332 01:10:02,100 --> 01:10:03,300 Naam. 1333 01:10:03,300 --> 01:10:03,800 Whew! 1334 01:10:03,800 --> 01:10:05,470 Kila mtu sawa katika suala hilo? 1335 01:10:05,470 --> 01:10:06,750 Hiyo ilikuwa ni utata. 1336 01:10:06,750 --> 01:10:09,380 Mada nzuri sana ya kwenda juu, kwa sababu wewe pengine 1337 01:10:09,380 --> 01:10:12,255 kwenda kupata baadhi gumu mambo kama hayo juu ya jaribio. 1338 01:10:12,255 --> 01:10:13,350 Naam. 1339 01:10:13,350 --> 01:10:13,850 Baridi. 1340 01:10:13,850 --> 01:10:16,014 1341 01:10:16,014 --> 01:10:18,430 Mimi itabidi kuweka wewe kupata 100 juu ya moja mstari na kisha 10 kwa upande mwingine. 1342 01:10:18,430 --> 01:10:21,468 Naam, nzuri sana. 1343 01:10:21,468 --> 01:10:26,350 >> Sawa, sasa nyie kupata nafasi ya kuwa TAS. 1344 01:10:26,350 --> 01:10:30,600 Kupata kujibu zote nzuri barua pepe kwamba mimi wakati mwingine kupata. 1345 01:10:30,600 --> 01:10:34,290 >> Kwa hiyo, Ndugu Andi, naona Nadhani kitu ni kwenda vibaya na mkusanyaji yangu. 1346 01:10:34,290 --> 01:10:37,910 Nina hakika kwamba kanuni yangu ni sahihi, lakini mimi kuendelea kupata kosa segmentation 1347 01:10:37,910 --> 01:10:39,074 kila wakati mimi kukimbia. 1348 01:10:39,074 --> 01:10:39,740 Nini kinaendelea? 1349 01:10:39,740 --> 01:10:42,844 Tafadhali msaada, kura ya upendo. 1350 01:10:42,844 --> 01:10:45,740 1351 01:10:45,740 --> 01:10:49,410 >> Kama nyie got kitu kama kwamba jinsi gani unaweza kuitikia? 1352 01:10:49,410 --> 01:10:51,860 Hizi ni kweli ya kawaida sana maswali tutakuuliza wewe. 1353 01:10:51,860 --> 01:10:54,090 Ni kama, tutaweza kukupa mazingira, tutaweza kutupa 1354 01:10:54,090 --> 01:10:56,350 nadhani wako bora katika nini kinaendelea. 1355 01:10:56,350 --> 01:11:00,710 Mtu yeyote kuwa kumchoma katika nini kinaendelea? 1356 01:11:00,710 --> 01:11:02,654 Yeah? 1357 01:11:02,654 --> 01:11:06,056 >> Watazamaji: Labda dereferenced null, kitu kama pointer 1358 01:11:06,056 --> 01:11:08,924 ni akionyesha kitu null. 1359 01:11:08,924 --> 01:11:11,590 PROFESA: Yeah, kwamba d kuwa mfano wa wakati ambayo ingeweza kutokea. 1360 01:11:11,590 --> 01:11:14,467 Lakini nini picha kubwa ya nini kinaendelea hapa? 1361 01:11:14,467 --> 01:11:17,050 Watazamaji: Je, ni wewe ni kujaribu kupata kumbukumbu kwamba wewe si 1362 01:11:17,050 --> 01:11:18,175 zinatakiwa kuwa na upatikanaji wa? 1363 01:11:18,175 --> 01:11:19,200 PROFESA: Hasa. 1364 01:11:19,200 --> 01:11:24,800 Hivyo kufikiria seg kosa, mbali mipaka, vikwazo eneo katika kumbukumbu 1365 01:11:24,800 --> 01:11:27,780 kwamba unapaswa kuwa kugusa. 1366 01:11:27,780 --> 01:11:31,670 >> Hivyo pretty much wakati wewe ni kujaribu kwa index-- kama kwa mfano, 1367 01:11:31,670 --> 01:11:34,110 umefanya alitangaza safu kutoka sifuri hadi tisa. 1368 01:11:34,110 --> 01:11:37,360 Lakini wewe kujaribu kugusa kwamba 10 thamani, huna upatikanaji wa jambo hilo. 1369 01:11:37,360 --> 01:11:38,694 Kwa kuwa si amekiri kuwa ni. 1370 01:11:38,694 --> 01:11:40,943 Na hivyo kompyuta yako ni kwenda kuangalia kwamba kama, 1371 01:11:40,943 --> 01:11:43,440 uh oh, wewe ni kujaribu kwenda nje ya mipaka ya ripoti. 1372 01:11:43,440 --> 01:11:45,270 Mimi nina kwenda kukupa segmentation kosa. 1373 01:11:45,270 --> 01:11:46,590 >> Fikiria kama sehemu, sawa? 1374 01:11:46,590 --> 01:11:49,665 Sehemu ya ziada, kosa hilo ni wakati wewe kujaribu uvunjaji kitu 1375 01:11:49,665 --> 01:11:50,790 na unapaswa kuwa huko. 1376 01:11:50,790 --> 01:11:53,660 Segmentation kosa ni wakati wowote wewe kujaribu kugusa mambo 1377 01:11:53,660 --> 01:11:54,970 kwamba unapaswa kuwa kugusa. 1378 01:11:54,970 --> 01:11:56,815 >> Mifano jambo la kawaida ni ripoti. 1379 01:11:56,815 --> 01:11:58,940 Bila shaka, kama wewe ni kujaribu kugusa kwamba alikuwa null, 1380 01:11:58,940 --> 01:12:00,220 ambayo ingeweza pia kazi vizuri. 1381 01:12:00,220 --> 01:12:02,300 Kama pointer yako alikuwa anajaribu kugusa mambo ambayo hawapaswi kugusa, 1382 01:12:02,300 --> 01:12:03,730 kwamba pia anaweza kufanya kazi pamoja. 1383 01:12:03,730 --> 01:12:07,120 Wengi kawaida utasikia kuona hii katika safu. 1384 01:12:07,120 --> 01:12:07,740 Kila mtu mwema? 1385 01:12:07,740 --> 01:12:10,374 >> Watazamaji: Hivyo kama unataka kupata hatua 10 1386 01:12:10,374 --> 01:12:12,290 na kuna tu kikomo ya tisa au kitu. 1387 01:12:12,290 --> 01:12:13,160 >> PROFESA: Yeah, kwa uhakika. 1388 01:12:13,160 --> 01:12:13,660 Pretty much. 1389 01:12:13,660 --> 01:12:15,930 1390 01:12:15,930 --> 01:12:16,430 Baridi. 1391 01:12:16,430 --> 01:12:19,070 1392 01:12:19,070 --> 01:12:19,920 >> Ndugu Andi. 1393 01:12:19,920 --> 01:12:23,440 Hivyo sisi tumepewa hizi za ajabu mambo kuitwa kila aina. 1394 01:12:23,440 --> 01:12:25,472 Kama kuunganisha sort-- kama sisi msumeno katika mfano wakati 1395 01:12:25,472 --> 01:12:27,180 Daudi alifanya nzima Jambo katika class-- kwa nini, 1396 01:12:27,180 --> 01:12:29,760 kama ni hivyo kwa kasi zaidi kuliko yoyote ya aina nyingine, 1397 01:12:29,760 --> 01:12:33,310 kwa nini sisi hata bother kujua yoyote ya aina nyingine? 1398 01:12:33,310 --> 01:12:35,100 >> Ni swali hili kweli kuuliza wewe nini? 1399 01:12:35,100 --> 01:12:36,659 Nini tatu word-- 1400 01:12:36,659 --> 01:12:37,950 Watazamaji: Nini biashara-off? 1401 01:12:37,950 --> 01:12:38,530 PROFESA: Hasa. 1402 01:12:38,530 --> 01:12:39,946 Hilo ndilo swali kuuliza. 1403 01:12:39,946 --> 01:12:43,682 Nini biashara-off kati ya Kuunganisha aina mistari aina nyingine yoyote? 1404 01:12:43,682 --> 01:12:45,850 >> Watazamaji: inachukua kumbukumbu, sawa? 1405 01:12:45,850 --> 01:12:47,720 >> PROFESA: Je, kueleza kwamba kidogo zaidi? 1406 01:12:47,720 --> 01:12:49,490 Kwanza hebu kueleza Unganisha kuhifadhi. 1407 01:12:49,490 --> 01:12:50,970 Ni kwa jinsi gani kuunganisha aina kazi? 1408 01:12:50,970 --> 01:12:55,220 >> Watazamaji: Hivyo ni kazi na kugawa kila kitu katika nusu 1409 01:12:55,220 --> 01:13:00,660 na kisha kuweka pamoja na reallocating hivyo ili, 1410 01:13:00,660 --> 01:13:02,862 kama kila wakati kuunganisha seti. 1411 01:13:02,862 --> 01:13:03,820 PROFESA: Pretty sana. 1412 01:13:03,820 --> 01:13:06,861 Hivyo siwezi kuteka hii nje, lakini ingekuwa kuchukua yangu dakika tano kuteka ni nje. 1413 01:13:06,861 --> 01:13:10,220 Kuangalia nyuma juu ya slides sehemu ambapo sisi kufunikwa Unganisha namna yo yote. 1414 01:13:10,220 --> 01:13:10,790 Hasa. 1415 01:13:10,790 --> 01:13:13,406 >> Hivyo njia kuunganisha aina matendo je, ni mgawanyiko mambo katika nusu, 1416 01:13:13,406 --> 01:13:15,780 na kisha tu inaangalia maadili ya kwanza ya wote 1417 01:13:15,780 --> 01:13:17,000 na aina tu kwamba. 1418 01:13:17,000 --> 01:13:20,364 Kuendelea inajenga arrays mpya na unaweka mambo zaidi na zaidi katika utaratibu. 1419 01:13:20,364 --> 01:13:23,030 Na hivyo wakati hiyo ni kweli, kweli haraka kwa sababu it's-- unajua, 1420 01:13:23,030 --> 01:13:25,380 tafuta binary ni n logi ya n. 1421 01:13:25,380 --> 01:13:27,880 Wewe ni kujenga mengi arrays mbalimbali kwamba wewe ni 1422 01:13:27,880 --> 01:13:29,700 kutumia kiasi kikubwa cha kumbukumbu. 1423 01:13:29,700 --> 01:13:33,080 Na hivyo wakati ni kasi, biashara mbali hapa ni kwamba unatumia kumbukumbu zaidi. 1424 01:13:33,080 --> 01:13:38,490 >> Na hivyo, ladha, aina na utafutaji walikuwa kufunikwa mengi zaidi mwaka huu 1425 01:13:38,490 --> 01:13:41,610 kuliko wao wamekuwa katika miaka ya nyuma. 1426 01:13:41,610 --> 01:13:45,100 Nyie lazima kuona kwamba yalijitokeza ipasavyo juu ya jaribio. 1427 01:13:45,100 --> 01:13:49,160 Napenda dhahiri kutumia muda kwenda juu ya nini yote ya aina mbalimbali 1428 01:13:49,160 --> 01:13:52,320 ni, tafuta jinsi binary, jinsi linear kazi ya utafutaji. 1429 01:13:52,320 --> 01:13:54,750 Jinsi ya labda pseudocode kanuni hizo nje. 1430 01:13:54,750 --> 01:13:55,950 Ni mara mbio ni nini? 1431 01:13:55,950 --> 01:13:59,210 Kitu kama mbio nyakati ni sana rahisi nakala chini kwenye karatasi kumbuka, 1432 01:13:59,210 --> 01:13:59,710 sawa? 1433 01:13:59,710 --> 01:14:01,420 >> Ni kweli ni vigumu wakati uko katikati ya mtihani 1434 01:14:01,420 --> 01:14:02,390 na una kufikiri kuwa nje. 1435 01:14:02,390 --> 01:14:03,160 Nakala yake chini. 1436 01:14:03,160 --> 01:14:05,550 Mimi kuhakikisha uko kwenda haja ya kujua kwamba. 1437 01:14:05,550 --> 01:14:06,860 Biashara awamu ya pili ni nini? 1438 01:14:06,860 --> 01:14:10,064 Kesi mbaya, matukio bora kesi kwa ajili yao wote, kupata sana kujua. 1439 01:14:10,064 --> 01:14:10,564 Yeah? 1440 01:14:10,564 --> 01:14:12,730 >> Watazamaji: Je, tunahitaji kujua jinsi ya kanuni Unganisha aina? 1441 01:14:12,730 --> 01:14:15,470 Kama, tunahitaji kumbuka kujirudia? 1442 01:14:15,470 --> 01:14:18,950 >> PROFESA: Mimi sana shaka, tu kwa sababu ni kama haki ngumu. 1443 01:14:18,950 --> 01:14:22,282 Lakini inaweza kuwa infeasible kama sisi kuuliza wewe kutumia pseudocode nje. 1444 01:14:22,282 --> 01:14:22,781 Naam. 1445 01:14:22,781 --> 01:14:25,470 1446 01:14:25,470 --> 01:14:29,170 >> Yep, sawa, moja zaidi. 1447 01:14:29,170 --> 01:14:31,387 Hii inaweza wamekuja katika wewe mwisho kipande katika kidogo. 1448 01:14:31,387 --> 01:14:42,101 1449 01:14:42,101 --> 01:14:43,090 Yeah? 1450 01:14:43,090 --> 01:14:44,930 Je, kila mtu kusikia kwamba? 1451 01:14:44,930 --> 01:14:48,360 >> OK, hivyo pretty much kwanza ya wote, ni aina gani ya mpango 1452 01:14:48,360 --> 01:14:51,000 itakuwa kutoa pato kama hii? 1453 01:14:51,000 --> 01:14:54,350 Kumbuka sisi aliuliza wewe kujifunza kuhusu aina hii mpya ya debugging chombo? 1454 01:14:54,350 --> 01:14:57,340 Jina lake lilikuwa lipi? 1455 01:14:57,340 --> 01:14:59,460 Valgrind, haki 1456 01:14:59,460 --> 01:15:02,600 >> Ilikuwa ni mpango ambapo unaweza wito kwamba anaweza 1457 01:15:02,600 --> 01:15:05,940 kuweka wimbo wa kumbukumbu zote uko kutumia katika mpango wako na kinachoendelea. 1458 01:15:05,940 --> 01:15:11,090 Hivyo kama wewe nimepata kitu, kama, dhahiri waliopotea, 40 ka katika kuzuia moja. 1459 01:15:11,090 --> 01:15:14,870 Pengine wewe si kukumbuka kwa bure hilo. 1460 01:15:14,870 --> 01:15:18,710 Kwa sababu kama unatumia ka ya kumbukumbu, hiyo ina maana umefanya kupatikana kwamba kumbukumbu, 1461 01:15:18,710 --> 01:15:20,240 lakini wewe hawajaweza kwa bure. 1462 01:15:20,240 --> 01:15:21,948 Kwa hiyo unataka kufanya kuhakikisha kwamba uko pia 1463 01:15:21,948 --> 01:15:31,420 kutumia free-- hiyo ni function-- kwa bure zote 1464 01:15:31,420 --> 01:15:34,930 ya kumbukumbu reallocated na malloc. 1465 01:15:34,930 --> 01:15:35,500 >> Baridi. 1466 01:15:35,500 --> 01:15:37,140 Hivyo slide huu, mimi itabidi it up. 1467 01:15:37,140 --> 01:15:41,050 Ni kila mahali katika mengi ya mihadhara, katika mengi ya slides sehemu. 1468 01:15:41,050 --> 01:15:44,254 Kweli unataka kuhakikisha wewe tu kujua yote haya. 1469 01:15:44,254 --> 01:15:47,170 Aidha katika kumbuka karatasi yako au kama wewe wanataka kukariri, kujisikia huru na. 1470 01:15:47,170 --> 01:15:48,836 Hiyo ni kweli, kweli, kweli ni muhimu. 1471 01:15:48,836 --> 01:15:53,200 1472 01:15:53,200 --> 01:15:56,890 >> Pia ni nzuri sana swali kwamba tunaweza kuomba. 1473 01:15:56,890 --> 01:16:00,320 Kwa nini Uchaguzi sort-- kuangalia Uchaguzi sort-- wote wa runtimes 1474 01:16:00,320 --> 01:16:02,060 ni n squared. 1475 01:16:02,060 --> 01:16:06,714 Bila kujali jinsi orodha suala la wewe kama, hivyo kwa nini ni Uchaguzi sort-- 1476 01:16:06,714 --> 01:16:08,630 Mimi nitakupa guys 30 pili kufikiri juu ya hili. 1477 01:16:08,630 --> 01:16:10,700 Kwa sababu ni aina ya utata. 1478 01:16:10,700 --> 01:16:12,710 Inahusisha baadhi ya mawazo dhana. 1479 01:16:12,710 --> 01:16:16,470 Kwa nini mara kukimbia kuwa sawa katika wote matukio mbaya na bora kesi? 1480 01:16:16,470 --> 01:16:28,850 1481 01:16:28,850 --> 01:16:30,000 >> Yeah? 1482 01:16:30,000 --> 01:16:38,084 >> Watazamaji: Kwa sababu Uteuzi aina kila msimamo au nafasi katika hii safu kidogo 1483 01:16:38,084 --> 01:16:40,350 Jambo au chochote. 1484 01:16:40,350 --> 01:16:44,430 Hivyo hata katika bora kesi, hata kama ni kikamilifu yamepangwa, 1485 01:16:44,430 --> 01:16:47,380 bado bila kuwa kama, sawa, moja. 1486 01:16:47,380 --> 01:16:49,000 Katika nafasi yangu ya kwanza nina moja. 1487 01:16:49,000 --> 01:16:50,250 Na kwenda kwa njia ya wote. 1488 01:16:50,250 --> 01:16:51,249 OK, moja ni ndogo. 1489 01:16:51,249 --> 01:16:53,053 Na kisha unaendelea tena na ni kama, sawa, wawili 1490 01:16:53,053 --> 01:16:54,594 ni ndogo kuliko mambo yote. 1491 01:16:54,594 --> 01:16:56,804 Lakini bado ana kuangalia kila mmoja na kila mmoja. 1492 01:16:56,804 --> 01:16:57,470 PROFESA: Naam. 1493 01:16:57,470 --> 01:17:00,490 Hivyo kwa mfano, hebu sema tu tuna orodha, tayari Iliyopangwa, 1494 01:17:00,490 --> 01:17:03,390 safu moja hadi tano. 1495 01:17:03,390 --> 01:17:07,100 Njia hiyo aina Uchaguzi ni kwamba huenda kwa njia, ni hundi hizi mbili. 1496 01:17:07,100 --> 01:17:08,234 Basi ni hundi hizo mbili. 1497 01:17:08,234 --> 01:17:09,650 Na kisha ni hundi, na ni hundi. 1498 01:17:09,650 --> 01:17:13,285 Anaendelea kuangalia wote, bila kujali kama au si 1499 01:17:13,285 --> 01:17:14,160 ni kweli yamepangwa. 1500 01:17:14,160 --> 01:17:16,450 Kwa sababu hiyo ni tu njia ya aina kazi. 1501 01:17:16,450 --> 01:17:19,530 >> Na hivyo swali hili ni aina ya kama swali dhana tutakuuliza. 1502 01:17:19,530 --> 01:17:21,430 Ambapo kwanza, kwa kujua nini aina Uchaguzi 1503 01:17:21,430 --> 01:17:23,304 ni, haki, kuwa na uwezo kujibu swali. 1504 01:17:23,304 --> 01:17:26,200 Wewe kuwa na uwezo wa kuelewa conceptually nini kinaendelea. 1505 01:17:26,200 --> 01:17:30,760 Na kisha unaweza kuomba na kufikiri, OK hebu tu kufikiria mazingira ya kesi mbaya. 1506 01:17:30,760 --> 01:17:32,230 Wao ni wote katika utaratibu wa kushuka. 1507 01:17:32,230 --> 01:17:33,290 Jinsi gani yanayoathiri yake? 1508 01:17:33,290 --> 01:17:34,650 >> Nini kama ni wakipanda ili? 1509 01:17:34,650 --> 01:17:35,640 Kama ni tayari Iliyopangwa? 1510 01:17:35,640 --> 01:17:37,240 Jinsi gani yanayoathiri runtimes? 1511 01:17:37,240 --> 01:17:40,270 Na kisha Uteuzi aina, utasikia taarifa kuwa haina kweli jambo. 1512 01:17:40,270 --> 01:17:43,500 Kwa sababu wewe ni kuangalia zote maadili bila kujali nini kinatokea. 1513 01:17:43,500 --> 01:17:45,810 >> Na hivyo mambo vizuri kukumbuka. 1514 01:17:45,810 --> 01:17:50,290 Kwa nini baadhi aina tofauti na wengine na namna bora na matukio ya kesi mbaya 1515 01:17:50,290 --> 01:17:52,740 utaathiri wote. 1516 01:17:52,740 --> 01:17:56,700 >> Mimi nina kwenda kwa kweli kugonga katika aina kwa sababu hiyo itakuwa juu ya jaribio. 1517 01:17:56,700 --> 01:17:57,199 Naam. 1518 01:17:57,199 --> 01:18:00,820 1519 01:18:00,820 --> 01:18:01,320 SAWA. 1520 01:18:01,320 --> 01:18:05,590 Kuna dakika sita wa kushoto. 1521 01:18:05,590 --> 01:18:09,880 Naweza kuchukua dakika tatu ya maswali. 1522 01:18:09,880 --> 01:18:12,290 Mimi pia hutegemea kuzunguka kwa kama dakika 20 baada ya kifungu cha 1523 01:18:12,290 --> 01:18:13,850 kama unataka kuuliza maswali kama vile. 1524 01:18:13,850 --> 01:18:16,330 Je, mtu yeyote tu na kwa kweli mafupi maswali au masuala dhana 1525 01:18:16,330 --> 01:18:17,360 wao uko wazi juu hivi sasa? 1526 01:18:17,360 --> 01:18:17,832 Yeah? 1527 01:18:17,832 --> 01:18:19,720 >> Watazamaji: Je, unaweza kuongea kidogo kidogo kuhusu kampuni za bitwise? 1528 01:18:19,720 --> 01:18:20,280 >> PROFESA: Naam. 1529 01:18:20,280 --> 01:18:22,446 Waendeshaji bitwise hivyo ni kitu ambacho pengine 1530 01:18:22,446 --> 01:18:24,170 kutaka tu kuweka kwenye karatasi yako. 1531 01:18:24,170 --> 01:18:27,540 Hivyo quickly-- Sitaki kwenda sana katika kina 1532 01:18:27,540 --> 01:18:31,164 kwa sababu Kikuu cha Harvard, katika mapitio yao kikao, kufunikwa ni pretty vizuri. 1533 01:18:31,164 --> 01:18:33,080 Bitwise operator, kuna watano kati yao, sawa? 1534 01:18:33,080 --> 01:18:41,370 >> Kuna hii, ambayo ni x au kazi, kuna ampersand, ambayo ni na. 1535 01:18:41,370 --> 01:18:44,050 Bomba, ambayo ni au. 1536 01:18:44,050 --> 01:18:46,790 Na kisha una mbili aina mbalimbali za mabadiliko. 1537 01:18:46,790 --> 01:18:50,610 >> Kama mimi kukupa maadili mbili, kama Nawapa, kama, moja na moja. 1538 01:18:50,610 --> 01:18:52,390 Nini ambacho ingekuwa kutathmini kwa? 1539 01:18:52,390 --> 01:18:55,490 Kama mimi kukupa kweli na kweli, ni kweli? 1540 01:18:55,490 --> 01:18:56,930 Je kuhusu kweli au uongo? 1541 01:18:56,930 --> 01:18:57,830 Bado kweli, haki? 1542 01:18:57,830 --> 01:18:59,762 Kwa sababu kuna au. 1543 01:18:59,762 --> 01:19:01,220 Tutaweza zaidi uwezekano kukupa namba. 1544 01:19:01,220 --> 01:19:03,780 Basi kumbuka, moja sawa na kweli, sifuri ni sawa na za uongo. 1545 01:19:03,780 --> 01:19:07,407 Na tupate kutoa mambo haya wewe na kuuliza wewe kutuambia nini kinatokea. 1546 01:19:07,407 --> 01:19:10,240 Harvard inashughulikia ndani kwanza Dakika 10 ya kikao yao utafiti 1547 01:19:10,240 --> 01:19:11,230 kweli, kweli vizuri. 1548 01:19:11,230 --> 01:19:14,260 Hivyo nyie wanataka kufanya kuhakikisha kuangalia nyuma juu ya hilo. 1549 01:19:14,260 --> 01:19:16,387 >> Watazamaji: Je, pisa5 kwenda kuwa juu ya jaribio? 1550 01:19:16,387 --> 01:19:16,970 PROFESA: Hapana 1551 01:19:16,970 --> 01:19:18,240 Je, si hata kuangalia pisa5 hivi sasa. 1552 01:19:18,240 --> 01:19:18,810 Ni vigumu. 1553 01:19:18,810 --> 01:19:22,830 Tu hawana hata bother kuangalia pisa5. 1554 01:19:22,830 --> 01:19:25,665 >> Hata hivyo, kama baadhi ya mwanga na mapendekezo, mimi 1555 01:19:25,665 --> 01:19:28,320 kupendekeza wewe kuanza pisa5 haraka kama jaribio ni juu. 1556 01:19:28,320 --> 01:19:30,319 Hii itakuwa ni gumu wiki, lakini basi nyie 1557 01:19:30,319 --> 01:19:34,590 itakuwa kupita kwenye vilima ya rolling kijani na puppies, 1558 01:19:34,590 --> 01:19:36,115 na ni faini. 1559 01:19:36,115 --> 01:19:39,810 >> Darasa hili anapata muhimu rahisi baada ya pset tano. 1560 01:19:39,810 --> 01:19:41,560 Watazamaji: Ofisi ya masaa ni Jumapili, Jumatatu? 1561 01:19:41,560 --> 01:19:44,260 PROFESA: Yeah, hivyo masaa ya ofisi mapenzi Jumapili Jumatatu kwa ajili ya pset. 1562 01:19:44,260 --> 01:19:47,009 Ofisi ya masaa usiku wa leo kimsingi tu kuwa mapitio ya jaribio. 1563 01:19:47,009 --> 01:19:50,350 Kama mtu anataka kuja na kuuliza TAS swali, tutaweza kuwa huko. 1564 01:19:50,350 --> 01:19:53,220 >> Mimi itabidi kuchukua swali labda moja zaidi kama mtu ana swali? 1565 01:19:53,220 --> 01:19:53,809 Yeah? 1566 01:19:53,809 --> 01:19:55,850 Watazamaji: Wakati uko kufafanua nodes, [inaudible] 1567 01:19:55,850 --> 01:20:00,700 kama wewe kusema nyota nodi na kisha ijayo, gani kompyuta moja kwa moja 1568 01:20:00,700 --> 01:20:03,610 kuelewa kwamba wewe ni akimaanisha pointer mwingine? 1569 01:20:03,610 --> 01:20:04,580 >> PROFESA: Hapana 1570 01:20:04,580 --> 01:20:06,710 >> Watazamaji: Una relink ni [inaudible]? 1571 01:20:06,710 --> 01:20:09,270 >> PROFESA: Kwa hiyo kimsingi struct nodi ya ni, kumbuka, 1572 01:20:09,270 --> 01:20:12,620 ni kama kujenga nodi na basi una pointer iitwayo ijayo. 1573 01:20:12,620 --> 01:20:14,630 Wote wewe kufanya ni kuwa na muundo wa huko. 1574 01:20:14,630 --> 01:20:16,387 Una kuwapa kwamba pointer mahali fulani. 1575 01:20:16,387 --> 01:20:18,470 Hivyo kompyuta haina kujua nini ni kufanya bado. 1576 01:20:18,470 --> 01:20:20,250 Una kweli hawawajui wakati wewe ni kujenga orodha yako wanaohusishwa. 1577 01:20:20,250 --> 01:20:22,170 Na kwamba ni nini hasa pset 5 itakuwa juu. 1578 01:20:22,170 --> 01:20:24,106 Hivyo hakuna wasiwasi kuhusu yoyote ya kuwa hivi sasa. 1579 01:20:24,106 --> 01:20:26,380 >> Watazamaji: Hivyo hatuna haja ya kuzingatia sana juu ya orodha kiungo, tu 1580 01:20:26,380 --> 01:20:27,440 mkuu mimba? 1581 01:20:27,440 --> 01:20:30,980 >> PROFESA: Tu mwingi pretty much, foleni, orodha kiungo, miti, meza hash. 1582 01:20:30,980 --> 01:20:33,639 Tu kuwa na uwezo wa kujua nini hao. 1583 01:20:33,639 --> 01:20:35,680 Sisi siyo kwenda kuuliza wewe kama kitu chochote maalum 1584 01:20:35,680 --> 01:20:39,300 kwa sababu sisi si kweli amefanya pset kwamba inashughulikia yoyote ya kuwa bado. 1585 01:20:39,300 --> 01:20:45,540 >> Hivyo katika dakika mbili za mwisho kabla ya Mimi kukuweka huru kuua jaribio hili. 1586 01:20:45,540 --> 01:20:49,370 Pretty sana, kama, fikiria jinsi mbali nyie wamekuja katika darasa hili. 1587 01:20:49,370 --> 01:20:52,820 >> Nakumbuka wakati wiki mbili ya darasa hili, baadhi yenu 1588 01:20:52,820 --> 01:20:55,720 kutumia masaa matatu kuandika maji. 1589 01:20:55,720 --> 01:20:57,970 Muda gani itachukua wewe guys kuandika maji sasa? 1590 01:20:57,970 --> 01:20:59,670 Sekunde 30, labda? 1591 01:20:59,670 --> 01:21:01,810 Fikiria juu ya ni kiasi gani nyie wamejifunza. 1592 01:21:01,810 --> 01:21:04,320 CS ni chini kweli, kweli ngumu. 1593 01:21:04,320 --> 01:21:06,190 Hakuna shaka ya kwamba. 1594 01:21:06,190 --> 01:21:09,160 Ni vigumu, kwamba ni kwa nini hakuna mtu anasoma yake. 1595 01:21:09,160 --> 01:21:10,730 Ni vigumu tu. 1596 01:21:10,730 --> 01:21:11,650 Na ni kabisa faini. 1597 01:21:11,650 --> 01:21:14,150 >> Na mimi nina kweli fahari kwamba kila mtu ana yake hii alifanya mbali. 1598 01:21:14,150 --> 01:21:16,380 Psets si rahisi. 1599 01:21:16,380 --> 01:21:17,790 Wao kuchukua muda mwingi. 1600 01:21:17,790 --> 01:21:22,580 Nyie, mimi kamwe kuuliza wewe kuandika mchezo wa 15 au Vigenere juu ya pset. 1601 01:21:22,580 --> 01:21:24,160 Hakuna haja ya tu kituko nje juu ya hilo. 1602 01:21:24,160 --> 01:21:28,080 Wote sisi ni kupima hapa ni kufanya tathmini ya maarifa yako dhana, ikiwa ni pamoja 1603 01:21:28,080 --> 01:21:31,524 kama baadhi ya ujuzi wako msingi ya coding. 1604 01:21:31,524 --> 01:21:33,440 Mtihani imeundwa kuwa kweli changamoto. 1605 01:21:33,440 --> 01:21:36,180 Kama, ni iliyoundwa kwa wewe kupata 100. 1606 01:21:36,180 --> 01:21:39,880 Ni pia iliyoundwa kwa ajili yenu kwa pengine kuwa na uwezo wa kumaliza katika muda wa dakika 75. 1607 01:21:39,880 --> 01:21:41,995 Na hiyo ndiyo kabisa faini. 1608 01:21:41,995 --> 01:21:42,870 Nina mwanafunzi mwenyewe. 1609 01:21:42,870 --> 01:21:45,960 Mimi najua, I hate ni wakati mimi kutembea nje ya jaribio kuwa kama, shit. 1610 01:21:45,960 --> 01:21:47,044 Hiyo ilikuwa ni ngumu kweli kweli. 1611 01:21:47,044 --> 01:21:49,460 Pengine nini kinaendelea happen-- na kwamba ni kabisa faini, 1612 01:21:49,460 --> 01:21:50,751 Mimi nawaambia guys hivi sasa. 1613 01:21:50,751 --> 01:21:53,190 Njia juu ya mambo haya si juu wakati wote. 1614 01:21:53,190 --> 01:21:55,360 >> Na kwa wale ambao wamekuwa kupata, kama, 1615 01:21:55,360 --> 01:21:57,870 threes juu ya seti tatizo lako, hiyo haina maana wewe ni 1616 01:21:57,870 --> 01:21:59,536 kwenda kupata asilimia 60 katika darasa hili. 1617 01:21:59,536 --> 01:22:01,440 Kama kupata 60% juu ya Jaribio, kwamba hana 1618 01:22:01,440 --> 01:22:03,330 maana wewe ni kwenda kupata D katika darasa hili. 1619 01:22:03,330 --> 01:22:05,740 Tunaona, hasa mimi, kwa wale katika sehemu yangu, 1620 01:22:05,740 --> 01:22:07,406 Mimi naona ni vigumu nyie ni wote wanaofanya kazi. 1621 01:22:07,406 --> 01:22:09,190 Na mimi kuweka wimbo wa jambo hilo. 1622 01:22:09,190 --> 01:22:11,420 >> Nyie itakuwa vizuri. 1623 01:22:11,420 --> 01:22:14,580 Hakuna kumbukumbu ya kitaasisi ya furaha mwishoni mwa muhula. 1624 01:22:14,580 --> 01:22:16,840 Kwa sababu wote Harvard watoto ni kuwaambia marafiki zao, loo, wewe utakuwa na faini. 1625 01:22:16,840 --> 01:22:18,381 Hakuna mtu ni kuwaambia nyie kwamba hapa. 1626 01:22:18,381 --> 01:22:20,950 Hivyo nina kukuambia guys kwamba hapa. 1627 01:22:20,950 --> 01:22:22,280 >> Nyie itakuwa vizuri. 1628 01:22:22,280 --> 01:22:24,080 Mimi hivyo fahari ya yote ya nyie. 1629 01:22:24,080 --> 01:22:25,680 Mtihani itakuwa vigumu. 1630 01:22:25,680 --> 01:22:28,140 Kujifunza kwa ajili yake, na baadaye tu kutupa mbali. 1631 01:22:28,140 --> 01:22:31,280 Kupata tayari kujifunza mambo mapya. 1632 01:22:31,280 --> 01:22:33,990 Na kula pipi. 1633 01:22:33,990 --> 01:22:35,940 Tumekuwa na kura ya pipi. 1634 01:22:35,940 --> 01:22:37,760 >> Kupata usingizi usiku mzuri wa. 1635 01:22:37,760 --> 01:22:40,420 Je, si kulala, kwa sababu kwamba d kuwa kweli mbaya. 1636 01:22:40,420 --> 01:22:41,490 CS mengi ya mantiki. 1637 01:22:41,490 --> 01:22:44,960 Kama huna kulala, huwezi kazi, na ubongo wako hawezi kufanya kazi. 1638 01:22:44,960 --> 01:22:48,780 Na mimi itakuwa hapa kwa 20 ijayo dakika kama kuna mtu anataka hutegemea kuzunguka. 1639 01:22:48,780 --> 01:22:51,150 Nyie ni kwenda kumchinja. 1640 01:22:51,150 --> 01:22:53,000 Bahati nzuri. 1641 01:22:53,000 --> 01:22:55,663