1 00:00:00,000 --> 00:00:11,320 2 00:00:11,320 --> 00:00:13,260 >> DAVID Malan: Hello, na kuwakaribisha nyuma CS50. 3 00:00:13,260 --> 00:00:14,860 Hivyo hii ni ya mwisho wa wiki nne. 4 00:00:14,860 --> 00:00:16,680 Moja tu tangazo kwanza. 5 00:00:16,680 --> 00:00:19,600 Hivyo kinachojulikana tano Jumatatu ni kuja hii Jumatatu ijayo. 6 00:00:19,600 --> 00:00:22,800 Hii ni fursa ya kubadili kutoka SAT / UNSAT kwa daraja mbili, au kutoka 7 00:00:22,800 --> 00:00:24,130 barua daraja SAT / UNSAT. 8 00:00:24,130 --> 00:00:27,130 Annoyingly, mchakato kwamba haina zinahitaji sahihi, kwa sababu una kujaza 9 00:00:27,130 --> 00:00:28,770 nje moja ya aina ya wale pink kuongeza / tone. 10 00:00:28,770 --> 00:00:31,680 >> Kwa sababu kitaalam, SAT / UNSAT toleo na toleo barua daraja 11 00:00:31,680 --> 00:00:33,320 kuwa na idadi catalog tofauti. 12 00:00:33,320 --> 00:00:34,240 Lakini hakuna mpango mkubwa. 13 00:00:34,240 --> 00:00:36,620 Tu kuja kwangu au kwa Rob au Lauren katika hatua yoyote. 14 00:00:36,620 --> 00:00:39,550 Au barua pepe nasi kama huna aina ya makaratasi unahitaji leo, na sisi 15 00:00:39,550 --> 00:00:43,410 kuwa na uhakika na kukusaidia kuchukua huduma ya kwamba kabla ya Jumatatu. 16 00:00:43,410 --> 00:00:45,780 >> Haki ya wote, hivyo leo - 17 00:00:45,780 --> 00:00:47,630 kweli, kuna kidogo ya echo. 18 00:00:47,630 --> 00:00:51,070 Tunaweza sauti yangu chini kidogo? 19 00:00:51,070 --> 00:00:51,730 OK. 20 00:00:51,730 --> 00:00:54,850 Hivyo leo, sisi kuanzisha mada inayojulikana kama kuyatumia. 21 00:00:54,850 --> 00:00:57,770 Na mimi itabidi kukubali kwamba hii ni moja ya ngumu zaidi mada ya kwamba sisi huwa na 22 00:00:57,770 --> 00:01:00,960 kufunika katika darasa hili, au kweli yoyote utangulizi shaka kwamba anatumia C. 23 00:01:00,960 --> 00:01:05,510 >> Lakini kuchukua neno langu kwa ajili yake, hasa kama akili yako anahisi kidogo zaidi bent 24 00:01:05,510 --> 00:01:07,100 leo na katika wiki ijayo. 25 00:01:07,100 --> 00:01:10,340 Ni si mwakilishi wa wewe kupata yoyote mbaya wakati huu ni njia tu kwamba 26 00:01:10,340 --> 00:01:13,360 ni mada hasa kisasa kwamba mimi ahadi, wiki chache 27 00:01:13,360 --> 00:01:17,610 hivyo, itakuwa kuonekana yote pia yakawa moja kwa moja katika retrospect. 28 00:01:17,610 --> 00:01:18,720 >> Mimi bado kukumbuka siku hii. 29 00:01:18,720 --> 00:01:22,190 Mimi alikuwa ameketi katika Elliott Dining Hall, ameketi karibu na TF yangu Nishat Mehta, 30 00:01:22,190 --> 00:01:24,070 ambaye alikuwa mkazi wa Elliott nyumba. 31 00:01:24,070 --> 00:01:26,340 Na kwa sababu fulani, hii mada tu Clicks. 32 00:01:26,340 --> 00:01:29,430 Ambayo ni kusema kwamba mimi pia alijitahidi na ni kwa baadhi ya kiasi cha muda, lakini mimi 33 00:01:29,430 --> 00:01:33,610 kufanya bora yangu ya kusaidia kuepuka vile mapambano na mada kwamba hatimaye 34 00:01:33,610 --> 00:01:34,580 ni nguvu kabisa. 35 00:01:34,580 --> 00:01:37,350 >> Kwa kweli, moja ya mada tutaweza kujadili katika wiki ijayo ni kwamba 36 00:01:37,350 --> 00:01:41,130 ya usalama, na jinsi unaweza kweli kutumia mashine katika njia 37 00:01:41,130 --> 00:01:42,320 kwamba walikuwa si nia. 38 00:01:42,320 --> 00:01:45,850 Na wale exploitations ni kawaida matokeo ya mende makosa, kwamba sisi 39 00:01:45,850 --> 00:01:49,740 watu kufanya na si kuelewa baadhi ya ya utekelezaji ya msingi 40 00:01:49,740 --> 00:01:52,250 maelezo kupitia programu ambayo ni kufanywa. 41 00:01:52,250 --> 00:01:55,410 >> Sasa kufanya hii wanaonekana mtumiaji wote zaidi kirafiki, nilifikiri ningependa kucheza 10 42 00:01:55,410 --> 00:01:59,680 pili hakikisho ya claymation kidogo takwimu aitwaye Binky ambaye aliletwa 43 00:01:59,680 --> 00:02:03,020 maisha na rafiki ya yetu katika Stanford, profesa Nick Parlante. 44 00:02:03,020 --> 00:02:06,753 Hivyo naomba kukupa hii teaser ya Binky hapa. 45 00:02:06,753 --> 00:02:09,520 >> [Video avspelning] 46 00:02:09,520 --> 00:02:10,380 >> -Hey, Binky. 47 00:02:10,380 --> 00:02:11,050 Kuamka. 48 00:02:11,050 --> 00:02:13,610 Ni wakati kwa ajili ya kujifurahisha pointer. 49 00:02:13,610 --> 00:02:14,741 >> -Ni nini hiyo? 50 00:02:14,741 --> 00:02:16,440 Kujifunza kuhusu kuyatumia? 51 00:02:16,440 --> 00:02:17,928 Oh, goodie. 52 00:02:17,928 --> 00:02:18,920 >> [MWISHO video avspelning] 53 00:02:18,920 --> 00:02:20,670 >> DAVID Malan: Hiyo ni Stanford sayansi ya kompyuta. 54 00:02:20,670 --> 00:02:23,194 Hivyo zaidi juu ya kwamba kuja. 55 00:02:23,194 --> 00:02:24,930 >> [Makofi] 56 00:02:24,930 --> 00:02:26,660 >> DAVID Malan: Samahani, Nick. 57 00:02:26,660 --> 00:02:30,680 >> Hivyo kukumbuka kuwa mara ya mwisho sisi kumalizika hii cliffhanger kweli kusisimua 58 00:02:30,680 --> 00:02:32,960 ambapo kazi hii tu hawakuwa na kazi. 59 00:02:32,960 --> 00:02:34,960 Angalau intuitively, waliona kama ni lazima kazi. 60 00:02:34,960 --> 00:02:37,600 Tu swapping maadili wa wawili integers. 61 00:02:37,600 --> 00:02:40,915 Lakini kukumbuka kwamba wakati sisi kuchapishwa awali ya maadili katika moja kuu, na 62 00:02:40,915 --> 00:02:44,210 mbili, bado walikuwa moja na mbili na si mbili na moja. 63 00:02:44,210 --> 00:02:46,070 >> Hivyo basi mimi kweli kubadili juu ya appliance. 64 00:02:46,070 --> 00:02:50,180 Na niliandika juu kidogo ya maadili ya kiunzi katika mapema hapa, ambapo mimi kudai kwamba x 65 00:02:50,180 --> 00:02:52,500 itakuwa 1, y itakuwa 2. 66 00:02:52,500 --> 00:02:54,810 Mimi kisha magazeti nje wote wa zao maadili na f magazeti. 67 00:02:54,810 --> 00:02:57,540 >> Mimi kisha kudai chini hapa kwamba tunakwenda kubadilishana nao. 68 00:02:57,540 --> 00:03:00,800 Mimi kushoto doa tupu hapa kwetu kujaza leo katika muda tu. 69 00:03:00,800 --> 00:03:03,380 Basi, mimi nina kwenda kudai kwamba vigezo mbili wamekuwa walibadilishana. 70 00:03:03,380 --> 00:03:04,770 Basi mimi nina kwenda magazeti yao nje tena. 71 00:03:04,770 --> 00:03:07,090 Na hivyo hopefully, mimi lazima angalia 1, 2. 72 00:03:07,090 --> 00:03:07,380 2, 1. 73 00:03:07,380 --> 00:03:09,830 Hiyo ni rahisi super lengo hivi sasa. 74 00:03:09,830 --> 00:03:12,430 >> Hivyo ni jinsi gani sisi kwenda juu swapping mbili vigezo? 75 00:03:12,430 --> 00:03:17,220 Vizuri kama napendekeza hapa kwamba hawa vikombe wanaweza kuwakilisha kumbukumbu katika kompyuta. 76 00:03:17,220 --> 00:03:19,070 Hii ni kuumwa chache, hii mwingine ni kuumwa wachache. 77 00:03:19,070 --> 00:03:23,260 Inaweza tuna kujitolea kuja juu ya juu na kuchanganya sisi baadhi ya vinywaji, kama familiar? 78 00:03:23,260 --> 00:03:23,920 Kuja juu juu. 79 00:03:23,920 --> 00:03:24,815 Nini jina lako? 80 00:03:24,815 --> 00:03:25,260 >> JESS: Jess. 81 00:03:25,260 --> 00:03:25,690 >> DAVID Malan: Jess? 82 00:03:25,690 --> 00:03:26,540 Kuja juu juu, Jess. 83 00:03:26,540 --> 00:03:29,180 Kama wewe huna akili, tuna kuweka Google vya juu yenu ili tuweze 84 00:03:29,180 --> 00:03:30,430 immortalize hii. 85 00:03:30,430 --> 00:03:32,800 86 00:03:32,800 --> 00:03:34,670 OK, kioo. 87 00:03:34,670 --> 00:03:37,250 Kurekodi video. 88 00:03:37,250 --> 00:03:43,103 Na sawa, sisi ni nzuri kwa kwenda na Jess hapa. 89 00:03:43,103 --> 00:03:43,810 Wote haki. 90 00:03:43,810 --> 00:03:45,120 Nice kukutana na wewe. 91 00:03:45,120 --> 00:03:47,720 >> Basi nini Ningependa kufanya hapa - kama unaweza, kabisa haraka - 92 00:03:47,720 --> 00:03:51,040 tu hutoka sisi kioo nusu ya machungwa juisi na nusu glasi ya maziwa, 93 00:03:51,040 --> 00:03:55,710 anayewakilisha ufanisi namba 1 katika kikombe kimoja na 2 katika kikombe mengine. 94 00:03:55,710 --> 00:04:01,380 95 00:04:01,380 --> 00:04:02,630 >> Hii ni kwenda kuwa nzuri Footage. 96 00:04:02,630 --> 00:04:04,910 97 00:04:04,910 --> 00:04:05,860 >> JESS: Sorry. 98 00:04:05,860 --> 00:04:06,330 >> DAVID Malan: Hapana, hakuna. 99 00:04:06,330 --> 00:04:08,703 Ni sawa. 100 00:04:08,703 --> 00:04:10,120 Nice. 101 00:04:10,120 --> 00:04:12,950 Haki wote, hivyo tuna ka nne yenye thamani ya maji ya machungwa. 102 00:04:12,950 --> 00:04:14,460 Tutaweza kuitwa ni thamani 1. 103 00:04:14,460 --> 00:04:16,579 Sasa mwingine ka manne yenye thamani ya maziwa. 104 00:04:16,579 --> 00:04:18,519 Itakuwa kuiita thamani 2. 105 00:04:18,519 --> 00:04:20,440 Hivyo x na y, kwa mtiririko huo. 106 00:04:20,440 --> 00:04:23,450 >> Haki ya wote, hivyo sasa kama kazi ya saa mkono - kwa ajili yenu, Jess, mbele ya wote 107 00:04:23,450 --> 00:04:24,270 wa wanafunzi wako - 108 00:04:24,270 --> 00:04:28,510 ni wabadilishane maadili ya x na y vile kwamba tunataka maji ya machungwa katika 109 00:04:28,510 --> 00:04:32,070 nyingine kikombe na maziwa katika kikombe hiki, jinsi nguvu wewe - kabla ya kweli kufanya 110 00:04:32,070 --> 00:04:34,020 yake - kwenda juu ya kufanya hii? 111 00:04:34,020 --> 00:04:35,220 >> OK, hekima uamuzi. 112 00:04:35,220 --> 00:04:36,340 Hivyo unahitaji kidogo zaidi kumbukumbu. 113 00:04:36,340 --> 00:04:38,190 Basi hebu kutenga muda kikombe, kama wewe. 114 00:04:38,190 --> 00:04:40,540 Na sasa kuendelea wabadilishane x na y. 115 00:04:40,540 --> 00:04:52,950 116 00:04:52,950 --> 00:04:53,530 >> Bora. 117 00:04:53,530 --> 00:04:54,420 Hivyo vizuri sana kufanyika. 118 00:04:54,420 --> 00:04:55,670 Asante sana, Jess. 119 00:04:55,670 --> 00:04:59,520 120 00:04:59,520 --> 00:05:00,020 Hapa ni. 121 00:05:00,020 --> 00:05:01,950 souvenir kidogo. 122 00:05:01,950 --> 00:05:04,350 >> OK, hivyo ni wazi, super rahisi wazo. 123 00:05:04,350 --> 00:05:07,500 Kabisa angavu kwamba tunahitaji kidogo zaidi ya kuhifadhi nafasi - katika fomu hii, 124 00:05:07,500 --> 00:05:09,750 kikombe - kama sisi kweli unataka wabadilishane vigezo hizi mbili. 125 00:05:09,750 --> 00:05:11,110 Basi hebu kufanya hasa kwamba. 126 00:05:11,110 --> 00:05:14,330 Juu hapa nchini kati ya mahali ambapo mimi kudai mimi nina kwenda kufanya baadhi swapping, mimi itabidi 127 00:05:14,330 --> 00:05:15,720 kwenda mbele na kutangaza temp. 128 00:05:15,720 --> 00:05:17,980 Na mimi itabidi kuweka sawa na, kusema, x. 129 00:05:17,980 --> 00:05:21,110 >> Basi mimi nina kwenda na mabadiliko ya thamani ya x tu kama alivyofanya Jess hapa na 130 00:05:21,110 --> 00:05:23,200 maziwa na maji ya machungwa kuwa sawa na y. 131 00:05:23,200 --> 00:05:27,460 Na mimi nina kwenda na mabadiliko y kuwa sawa na si x, kwa sababu sasa tunataka kuwa 132 00:05:27,460 --> 00:05:29,530 kukwama katika mduara, lakini badala ya temp. 133 00:05:29,530 --> 00:05:33,170 Ambapo mimi muda - au ambapo Jess muda kuweka maji ya machungwa 134 00:05:33,170 --> 00:05:35,460 kabla clobbering kwamba kikombe na maziwa. 135 00:05:35,460 --> 00:05:37,250 >> Hivyo basi mimi kwenda mbele sasa na kufanya hii. 136 00:05:37,250 --> 00:05:39,210 Ni wito noswap.c. 137 00:05:39,210 --> 00:05:41,190 Na sasa basi mimi kukimbia hakuna kubadilishana. 138 00:05:41,190 --> 00:05:43,910 Na hakika Mimi naona, kama mimi kupanua dirisha kidogo, kwamba 139 00:05:43,910 --> 00:05:45,160 x ni 1, y ni 2. 140 00:05:45,160 --> 00:05:47,230 Na kisha x ni 2, y ni 1. 141 00:05:47,230 --> 00:05:51,910 >> Lakini kukumbuka kwamba Jumatatu tulifanya mambo tofauti kidogo ambapo mimi 142 00:05:51,910 --> 00:05:56,760 badala kutekelezwa kazi msaidizi, kama wewe, kwamba ilikuwa kweli tupu. 143 00:05:56,760 --> 00:05:58,010 Mimi kuitwa ni wabadilishane. 144 00:05:58,010 --> 00:06:01,600 Mimi akampa vigezo mbili, na mimi kuitwa wao na mimi aliwaita b. 145 00:06:01,600 --> 00:06:04,380 >> Kusema ukweli, mimi naweza kuwaita x na y. 146 00:06:04,380 --> 00:06:06,040 Kuna kitu kuacha mimi kutoka kufanya hivyo. 147 00:06:06,040 --> 00:06:08,140 Lakini napenda kusema ni basi utata kidogo. 148 00:06:08,140 --> 00:06:11,910 Sababu wanakumbuka kwa Jumatatu kwamba sisi alidai kwamba hawa walikuwa vigezo 149 00:06:11,910 --> 00:06:13,650 nakala za maadili ya kupita in 150 00:06:13,650 --> 00:06:15,640 Hivyo tu machafuko na yako akili, nadhani, kama matumizi ya 151 00:06:15,640 --> 00:06:17,370 hasa vigezo sawa. 152 00:06:17,370 --> 00:06:20,150 >> Hivyo mimi itabidi badala kuwaita na b, tu kwa uwazi. 153 00:06:20,150 --> 00:06:21,840 Lakini tungeweza kuwaita zaidi kitu tunataka. 154 00:06:21,840 --> 00:06:26,280 Na mimi nina kwenda na nakala na kuweka ufanisi kanuni hii kutoka huko 155 00:06:26,280 --> 00:06:27,170 chini ndani hapa. 156 00:06:27,170 --> 00:06:29,110 Kwa sababu mimi tu kuona kwamba kazi. 157 00:06:29,110 --> 00:06:30,790 Hivyo kwamba ni katika sura nzuri. 158 00:06:30,790 --> 00:06:37,390 Na mimi itabidi kubadili x yangu x, yangu ili, y yangu b na y yangu b. 159 00:06:37,390 --> 00:06:39,130 >> Hivyo kwa maneno mengine, exact mantiki. 160 00:06:39,130 --> 00:06:40,850 exact kitu kwamba Jess alivyofanya. 161 00:06:40,850 --> 00:06:44,350 Na kisha jambo moja mimi kufanya up hapa, bila shaka, ni sasa waomba hii 162 00:06:44,350 --> 00:06:45,990 kazi, au piga kazi huu. 163 00:06:45,990 --> 00:06:50,430 Hivyo mimi wito huu kazi na mbili pembejeo, x na y, na wimbo wa Hifadhi. 164 00:06:50,430 --> 00:06:52,300 >> Haki ya wote, hivyo kimsingi kitu kimoja. 165 00:06:52,300 --> 00:06:55,570 Kwa kweli, nimekuwa pengine alifanya mpango usiokuwa tata na 166 00:06:55,570 --> 00:07:00,820 kuandika kazi kwamba tu kuchukua baadhi ya mistari sita ya maadili ambapo mimi 167 00:07:00,820 --> 00:07:02,970 hapo awali alikuwa kutekelezwa hii katika tatu tu. 168 00:07:02,970 --> 00:07:06,230 >> Hivyo basi mimi kwenda mbele sasa na remake hii, kufanya hakuna kubadilishana. 169 00:07:06,230 --> 00:07:07,920 Haki zote, mimi Star juu hapa. 170 00:07:07,920 --> 00:07:11,290 Hii inapaswa kuwa makosa kwamba waweza kuona inazidi kawaida kama yako 171 00:07:11,290 --> 00:07:12,380 mipango ya kupata ngumu zaidi. 172 00:07:12,380 --> 00:07:13,470 Lakini kuna fix rahisi. 173 00:07:13,470 --> 00:07:15,650 Hebu kitabu nyuma hadi hapa. 174 00:07:15,650 --> 00:07:18,190 >> Na nini makosa ya kwanza mimi nina kuona? 175 00:07:18,190 --> 00:07:19,520 Kinachojitokeza tamko. 176 00:07:19,520 --> 00:07:21,466 Je, kwamba kwa kawaida zinaonyesha? 177 00:07:21,466 --> 00:07:22,830 Oh, I forgot mfano. 178 00:07:22,830 --> 00:07:26,900 Nimesahau kufundisha mkusanyaji kwamba wabadilishane ni kwenda kuwepo hata ingawa yeye 179 00:07:26,900 --> 00:07:28,920 haipo katika mwanzo sana wa mpango. 180 00:07:28,920 --> 00:07:35,780 Hivyo nina kwenda tu kusema batili, wabadilishane, int, b int, semicolon. 181 00:07:35,780 --> 00:07:37,280 >> Hivyo mimi nina si kwenda reimplement yake. 182 00:07:37,280 --> 00:07:39,140 Lakini sasa ni mechi nini hapa chini. 183 00:07:39,140 --> 00:07:42,530 Na notisi, ukosefu wa semicolon hapa, ambayo si muhimu wakati 184 00:07:42,530 --> 00:07:43,200 utekelezaji. 185 00:07:43,200 --> 00:07:46,010 >> Hivyo basi mimi remake hii, kufanya hakuna kubadilishana. 186 00:07:46,010 --> 00:07:46,910 Bora zaidi sura. 187 00:07:46,910 --> 00:07:48,130 Kukimbia hakuna kubadilishana. 188 00:07:48,130 --> 00:07:48,740 Na damn it. 189 00:07:48,740 --> 00:07:51,650 Sasa tuko nyuma ambapo tulikuwa juu ya Jumatatu, ambapo jambo hakuwa wabadilishane. 190 00:07:51,650 --> 00:07:55,410 >> Na nini maelezo angavu kwa nini hii ni kesi? 191 00:07:55,410 --> 00:07:56,380 Yeah? 192 00:07:56,380 --> 00:07:57,630 >> MWANAFUNZI: [inaudible]. 193 00:07:57,630 --> 00:08:04,140 194 00:08:04,140 --> 00:08:05,230 >> DAVID Malan: Hasa. 195 00:08:05,230 --> 00:08:07,330 Hivyo na b ni nakala za x na y. 196 00:08:07,330 --> 00:08:10,680 Na kwa kweli, wakati wowote wewe tumekuwa wito kazi hivi sasa kwamba 197 00:08:10,680 --> 00:08:12,540 hupita vigezo kama ints - 198 00:08:12,540 --> 00:08:14,470 tu kama wabadilishane ni kutarajia hapa - 199 00:08:14,470 --> 00:08:16,270 nyie wamekuwa kupita katika nakala. 200 00:08:16,270 --> 00:08:19,150 >> Sasa kwa kuwa ina maana inachukua kidogo ya muda, kupasuliwa pili, kwa ajili ya 201 00:08:19,150 --> 00:08:23,270 kompyuta na nakala bits kutoka kwa mmoja kutofautiana katika bits ya mwingine. 202 00:08:23,270 --> 00:08:24,610 Lakini si kwamba kama mpango kubwa. 203 00:08:24,610 --> 00:08:25,920 Lakini wao ni hata hivyo nakala. 204 00:08:25,920 --> 00:08:30,020 >> Na hivyo kwa sasa, katika mazingira ya kubadilishana, Mimi kwa kweli kwa mafanikio 205 00:08:30,020 --> 00:08:31,180 kubadilisha b na. 206 00:08:31,180 --> 00:08:33,000 Kwa kweli, hebu kufanya haraka sanity kuangalia. 207 00:08:33,000 --> 00:08:36,830 Magazeti f ni% i, mpya line. 208 00:08:36,830 --> 00:08:38,770 Na kuziba hebu katika. 209 00:08:38,770 --> 00:08:41,830 Sasa hebu kufanya kitu kimoja na b. 210 00:08:41,830 --> 00:08:43,640 Na hebu kufanya kitu kimoja hapa. 211 00:08:43,640 --> 00:08:47,260 >> Na sasa, napenda nakala mistari hizo hizo tena chini ya kazi 212 00:08:47,260 --> 00:08:51,250 tatu baada yangu mistari ya kuvutia wangeweza kunyongwa, na 213 00:08:51,250 --> 00:08:53,270 magazeti b na bado tena. 214 00:08:53,270 --> 00:08:56,030 Hivyo sasa hebu kufanya hii, kufanya hakuna kubadilishana. 215 00:08:56,030 --> 00:08:58,430 Napenda kufanya dirisha terminal kidogo mirefu, ili tuweze kuona 216 00:08:58,430 --> 00:08:59,520 zaidi ya mara moja. 217 00:08:59,520 --> 00:09:00,860 >> Na kukimbia hakuna kubadilishana. 218 00:09:00,860 --> 00:09:04,000 x ni 1, y ni 2. ni 1, b ni 2. 219 00:09:04,000 --> 00:09:06,070 Na kisha, ni 2, b ni 1. 220 00:09:06,070 --> 00:09:09,390 Hivyo ni kazi, kama Jess alivyofanya hapa ndani ya kubadilishana. 221 00:09:09,390 --> 00:09:13,090 Lakini bila shaka, ni kutokuwa na athari juu ya vigezo katika kuu. 222 00:09:13,090 --> 00:09:15,360 >> Hivyo tuliona hila litupasalo sisi inaweza kurekebisha hili, haki? 223 00:09:15,360 --> 00:09:19,560 Wakati wewe ni wanakabiliwa na hii scoping suala hilo, unaweza tu Punt na kufanya x 224 00:09:19,560 --> 00:09:22,400 na y aina gani ya vigezo badala yake? 225 00:09:22,400 --> 00:09:23,390 >> Unaweza kufanya nao kimataifa. 226 00:09:23,390 --> 00:09:27,560 Kuziweka katika sana juu ya faili kama tulivyofanya, hata katika mchezo wa 15. 227 00:09:27,560 --> 00:09:28,890 Sisi kutumia variable kimataifa. 228 00:09:28,890 --> 00:09:32,420 Lakini katika mazingira ya mchezo 15, ni busara kuwa na kimataifa 229 00:09:32,420 --> 00:09:37,170 kutofautiana anayewakilisha bodi, kwa sababu ukamilifu wa 15.c ni kila 230 00:09:37,170 --> 00:09:38,650 kuhusu utekelezaji kwamba mchezo. 231 00:09:38,650 --> 00:09:41,470 Hiyo ni nini faili ipo ya kufanya. 232 00:09:41,470 --> 00:09:44,170 >> Lakini katika kesi hii hapa, mimi nina wito wabadilishane kazi. 233 00:09:44,170 --> 00:09:45,380 Nataka wabadilishane vigezo mbili. 234 00:09:45,380 --> 00:09:48,950 Na ni lazima kuanza kuhisi tu sloppy kama ufumbuzi wa wetu wote 235 00:09:48,950 --> 00:09:51,300 matatizo wakati sisi kukimbia katika wigo masuala ya kufanya hivyo ni wa kimataifa. 236 00:09:51,300 --> 00:09:54,730 Kwa sababu ya haraka sana mpango wetu ni kwenda kuwa fujo kabisa. 237 00:09:54,730 --> 00:09:57,760 Na sisi gani kwamba sana haba kama matokeo katika 15.c. 238 00:09:57,760 --> 00:10:00,470 >> Lakini zinageuka kuna njia bora kabisa. 239 00:10:00,470 --> 00:10:05,600 Hebu kweli kwenda nyuma na kufuta magazeti ya f, tu kurahisisha kanuni hii. 240 00:10:05,600 --> 00:10:09,160 Na napenda kupendekeza kwamba hii, kwa hakika, ni mbaya. 241 00:10:09,160 --> 00:10:15,990 Lakini kama mimi badala kuongeza katika asterisks baadhi na nyota, siwezi badala kugeuka hii 242 00:10:15,990 --> 00:10:18,670 kazi katika moja kwamba ni kweli kazi. 243 00:10:18,670 --> 00:10:25,020 >> Hivyo basi mimi kwenda nyuma hapa na kukubali kusema asterisks daima ni mgumu, 244 00:10:25,020 --> 00:10:26,170 hivyo mimi itabidi kusema nyota. 245 00:10:26,170 --> 00:10:27,660 Mimi itabidi fess hadi kuwa moja. 246 00:10:27,660 --> 00:10:28,190 Wote haki. 247 00:10:28,190 --> 00:10:30,190 Na sasa, je, Mimi naenda kwa nini badala yake? 248 00:10:30,190 --> 00:10:34,130 >> Hivyo kwanza ya yote, mimi nina kwenda bayana kwamba badala ya kupita katika int 249 00:10:34,130 --> 00:10:37,980 kazi wabadilishane, mimi nina badala ya kwenda kusema nyota int. 250 00:10:37,980 --> 00:10:39,170 Sasa, je, nyota zinaonyesha? 251 00:10:39,170 --> 00:10:41,970 Hii ni kwamba dhana ya pointer kwamba Binky, tabia claymation, alikuwa 252 00:10:41,970 --> 00:10:43,465 akimaanisha wakati iliyopita. 253 00:10:43,465 --> 00:10:47,610 >> Hivyo kama sisi kusema nyota int, maana ya hii sasa ni kwamba si kwenda kuwa 254 00:10:47,610 --> 00:10:49,110 kupita katika na thamani yake. 255 00:10:49,110 --> 00:10:50,350 Ni si kwenda na kunakiliwa in 256 00:10:50,350 --> 00:10:54,700 Badala yake, anuani ya ni kwenda kuwa kupita in 257 00:10:54,700 --> 00:10:57,840 >> Hivyo kukumbuka kwamba ndani ya kompyuta yako ni rundo zima la kumbukumbu, vinginevyo 258 00:10:57,840 --> 00:10:58,760 inayojulikana kama RAM. 259 00:10:58,760 --> 00:11:00,520 Na RAM kwamba ni haki nzima rundo ya ka. 260 00:11:00,520 --> 00:11:03,320 Hivyo kama Mac au PC yako ina mbili gigabytes, una 2 261 00:11:03,320 --> 00:11:05,760 bilioni ka ya kumbukumbu. 262 00:11:05,760 --> 00:11:08,440 >> Sasa hebu tu tuseme kwamba tu kuweka mambo nzuri na mpangilio, sisi 263 00:11:08,440 --> 00:11:09,450 hawawajui anwani - 264 00:11:09,450 --> 00:11:10,170 idadi - 265 00:11:10,170 --> 00:11:12,270 kwa kila Byte ya RAM katika kompyuta yako. 266 00:11:12,270 --> 00:11:15,410 Byte sana kwanza ya wale 2 bilioni ni kwa sifuri idadi. 267 00:11:15,410 --> 00:11:18,572 moja ijayo ni Byte namba moja, idadi mbili, njia yote juu juu, dot dot 268 00:11:18,572 --> 00:11:20,530 dot, kwa takribani bilioni 2. 269 00:11:20,530 --> 00:11:23,640 >> Hivyo unaweza idadi ya ka wa kumbukumbu katika kompyuta yako. 270 00:11:23,640 --> 00:11:26,460 Hivyo hebu kudhani kwamba kwamba ni nini maana sisi na anwani. 271 00:11:26,460 --> 00:11:31,360 Hivyo wakati mimi kuona int nyota a, nini kinaendelea kuwa kupita katika kubadilishana sasa ni 272 00:11:31,360 --> 00:11:32,830 anuani ya. 273 00:11:32,830 --> 00:11:37,150 Si thamani yake, lakini chochote posta yake anuani ni, hivyo kusema - 274 00:11:37,150 --> 00:11:38,810 eneo lake katika RAM. 275 00:11:38,810 --> 00:11:41,250 >> Na vile vile kwa b, mimi naenda kusema kitu kimoja. 276 00:11:41,250 --> 00:11:42,720 Int, nyota, b. 277 00:11:42,720 --> 00:11:46,350 Kama kando, kitaalam nyota inaweza kwenda katika maeneo mengine. 278 00:11:46,350 --> 00:11:50,140 Lakini tutaweza sanifisha juu ya nyota kuwa haki ya karibu na ya aina data. 279 00:11:50,140 --> 00:11:54,080 >> Hivyo wabadilishane saini sasa ina maana, nipe anuani ya int, na wito 280 00:11:54,080 --> 00:11:55,400 kwamba anwani. 281 00:11:55,400 --> 00:11:58,690 Na nipe anwani nyingine ya int na wito kwamba b anwani. 282 00:11:58,690 --> 00:12:01,120 >> Lakini sasa kanuni yangu hapa ina mabadiliko. 283 00:12:01,120 --> 00:12:03,470 Kwa sababu kama mimi kutangaza temp int - 284 00:12:03,470 --> 00:12:05,580 ambayo bado ni ya int aina - 285 00:12:05,580 --> 00:12:08,700 lakini mimi kuhifadhi ndani yake, aina gani ya thamani? 286 00:12:08,700 --> 00:12:12,870 Kuwa wazi, mimi kuweka na kanuni kama imeandikwa hivi sasa? 287 00:12:12,870 --> 00:12:14,360 >> Mimi nina kuweka eneo katika. 288 00:12:14,360 --> 00:12:16,500 Lakini mimi sijali kuhusu mahali sasa, haki? 289 00:12:16,500 --> 00:12:21,940 Temp ipo tu Jess 'tatu kikombe kuwepo, kwa madhumuni gani? 290 00:12:21,940 --> 00:12:23,090 Kuhifadhi thamani. 291 00:12:23,090 --> 00:12:24,830 Maziwa au maji ya machungwa. 292 00:12:24,830 --> 00:12:28,520 Si kweli kuhifadhi anwani ya aidha ya mambo hayo, ambayo anahisi 293 00:12:28,520 --> 00:12:31,200 kidogo nonsensical katika hii halisi dunia muktadha anyway. 294 00:12:31,200 --> 00:12:34,990 >> Hivyo kweli, nini nataka kuweka katika temp si anuani ya, lakini 295 00:12:34,990 --> 00:12:36,180 yaliyomo. 296 00:12:36,180 --> 00:12:41,930 Hivyo kama ni idadi kama 123, hii ni Byte 123 ya kumbukumbu ya kwamba tu 297 00:12:41,930 --> 00:12:45,090 hutokea kwa kuwa occupying, kwamba thamani katika hutokea kwa kuwa uvamizi. 298 00:12:45,090 --> 00:12:49,040 >> Kama mimi nataka kwenda anuani kwamba, Mimi haja ya kusema nyota a. 299 00:12:49,040 --> 00:12:52,610 Vile vile, kama ningekuwa na mabadiliko ya nini katika anuani, mimi kubadili 300 00:12:52,610 --> 00:12:53,570 hii kuanza. 301 00:12:53,570 --> 00:12:58,185 Kama nataka kuhifadhi katika nini katika mahali na nini katika eneo 302 00:12:58,185 --> 00:13:02,180 saa b, b nyota nyota. 303 00:13:02,180 --> 00:13:05,340 >> Hivyo katika muda mfupi, hata kama hii si kabisa kuzama katika bado - na mimi bila kutarajia 304 00:13:05,340 --> 00:13:06,560 kwamba ingekuwa hivyo haraka - 305 00:13:06,560 --> 00:13:11,100 kutambua kwamba wote mimi kufanya ni prefixing nyota hizi kwa vigezo yangu, 306 00:13:11,100 --> 00:13:13,350 Msemo si kunyakua maadili. 307 00:13:13,350 --> 00:13:14,520 Wala mabadiliko ya maadili. 308 00:13:14,520 --> 00:13:17,600 Lakini badala yake, kwenda kwa wale anwani na kupata thamani. 309 00:13:17,600 --> 00:13:21,430 Kwenda kwamba anwani na mabadiliko thamani huko. 310 00:13:21,430 --> 00:13:25,500 >> Hivyo sasa napenda kitabu nyuma hadi juu, tu kurekebisha line hii hapa, 311 00:13:25,500 --> 00:13:27,690 mabadiliko ya mfano kwa mechi. 312 00:13:27,690 --> 00:13:30,280 Lakini mimi sasa haja ya kufanya jambo moja nyingine. 313 00:13:30,280 --> 00:13:35,500 Shirikishi, kama nimekuwa iliyopita aina ya hoja wabadilishane kwamba ni kutarajia, 314 00:13:35,500 --> 00:13:37,245 nini kingine nahitaji mabadiliko katika kanuni yangu? 315 00:13:37,245 --> 00:13:39,750 316 00:13:39,750 --> 00:13:40,840 >> Wakati mimi wito wabadilishane. 317 00:13:40,840 --> 00:13:43,340 Kwa sababu sasa hivi, kile ni Mimi kupita wabadilishane bado? 318 00:13:43,340 --> 00:13:47,450 x thamani na thamani ya y, au maziwa na maji ya machungwa. 319 00:13:47,450 --> 00:13:48,510 Lakini mimi sitaki kufanya hivyo. 320 00:13:48,510 --> 00:13:51,060 Mimi badala unataka kupita katika nini? 321 00:13:51,060 --> 00:13:53,050 eneo la x na eneo la y. 322 00:13:53,050 --> 00:13:55,300 Je, ni anwani zao za posta, hivyo kusema. 323 00:13:55,300 --> 00:13:57,600 >> Hivyo kufanya hivyo, kuna Ampersand. 324 00:13:57,600 --> 00:13:59,260 Ampersand aina ya inaonekana kama anwani. 325 00:13:59,260 --> 00:14:03,240 hivyo n, Ampersand, anuani ya x, na anuani ya y. 326 00:14:03,240 --> 00:14:06,790 Hivyo ni makusudi kwamba sisi kutumia ampersands wakati wito kazi, 327 00:14:06,790 --> 00:14:10,230 na nyota wakati kutangaza na wakati utekelezaji wa kazi. 328 00:14:10,230 --> 00:14:14,220 >> Na tu kufikiria Ampersand kama anuani ya operator, na nyota kama 329 00:14:14,220 --> 00:14:15,490 kwenda huko operator - 330 00:14:15,490 --> 00:14:18,640 au, vizuri zaidi, dereference operator. 331 00:14:18,640 --> 00:14:23,480 Hivyo kwamba ni mengi yote ya maneno tu kusema kwamba sasa, hopefully, wabadilishane ni kwenda 332 00:14:23,480 --> 00:14:24,440 kuwa sahihi. 333 00:14:24,440 --> 00:14:26,550 >> Hebu kwenda mbele na kufanya - 334 00:14:26,550 --> 00:14:30,940 hebu kweli rename faili, wasije mpango huu bado kuitwa hakuna kubadilishana. 335 00:14:30,940 --> 00:14:33,240 Mimi kudai kwamba tutaweza kuiita swap.c sasa. 336 00:14:33,240 --> 00:14:35,670 Hivyo kufanya, wabadilishane. 337 00:14:35,670 --> 00:14:37,520 Dot, kufyeka, wabadilishane. 338 00:14:37,520 --> 00:14:40,210 >> Na sasa kwa kweli, ni 1 x, y ni 2. 339 00:14:40,210 --> 00:14:44,040 Na kisha, x ni 2, y ni moja. 340 00:14:44,040 --> 00:14:46,500 Naam hebu angalia kama hatuwezi kufanya hii kidogo kidogo tofauti kama kwa nini 341 00:14:46,500 --> 00:14:47,180 kinachoendelea hapa. 342 00:14:47,180 --> 00:14:51,250 Kwanza, napenda kuvuta wetu kuchora screen hapa. 343 00:14:51,250 --> 00:14:54,160 Na napenda kupendekeza kwa sasa - na wakati mimi kuteka hapa itakuwa huonekana 344 00:14:54,160 --> 00:14:58,660 hadi sasa kuna - basi mimi kupendekeza kwamba hapa ni rundo zima la kumbukumbu, au 345 00:14:58,660 --> 00:15:00,540 RAM, ndani ya kompyuta yangu. 346 00:15:00,540 --> 00:15:04,140 >> Na hii itakuwa bite ya simu, hebu sema, 1. 347 00:15:04,140 --> 00:15:05,720 Hii itakuwa ka namba 2. 348 00:15:05,720 --> 00:15:08,220 Na mimi itabidi kufanya rundo zima zaidi, na kisha rundo la dots dot dot 349 00:15:08,220 --> 00:15:10,880 zinaonyesha kwamba kuna bilioni 2 ya mambo haya. 350 00:15:10,880 --> 00:15:13,520 4, 5, na kadhalika. 351 00:15:13,520 --> 00:15:17,055 >> Hivyo kuna mitano ya kwanza ka ya kumbukumbu ya kompyuta yangu. 352 00:15:17,055 --> 00:15:17,560 Wote haki? 353 00:15:17,560 --> 00:15:19,060 Wachache sana nje ya bilioni 2. 354 00:15:19,060 --> 00:15:21,120 Lakini sasa mimi naenda kupendekeza zifuatazo. 355 00:15:21,120 --> 00:15:27,490 Mimi nina kwenda kupendekeza kwamba x ni kwenda kuhifadhi namba 1, na y ni kwenda 356 00:15:27,490 --> 00:15:29,690 kuhifadhi namba 2. 357 00:15:29,690 --> 00:15:35,000 Na napenda kwenda mbele sasa na inawakilisha maadili haya kama ifuatavyo. 358 00:15:35,000 --> 00:15:41,510 >> Hebu kufanya hii kama ifuatavyo. 359 00:15:41,510 --> 00:15:42,870 Nipe moja tu ya pili. 360 00:15:42,870 --> 00:15:44,150 Moja ya pili. 361 00:15:44,150 --> 00:15:45,680 OK. 362 00:15:45,680 --> 00:15:47,560 Nataka kufanya hii kidogo - 363 00:15:47,560 --> 00:15:50,440 hebu kufanya hii tena. 364 00:15:50,440 --> 00:15:53,250 Vinginevyo mimi nina kwenda na kutumia hiyo namba, pasipo kukusudia, 365 00:15:53,250 --> 00:15:54,230 mara nyingi. 366 00:15:54,230 --> 00:15:57,320 >> Hivyo tu hivyo tuna idadi tofauti kuzungumzia, hebu simu hii Byte 367 00:15:57,320 --> 00:16:03,391 simu 123, 124, 125, 126, na dot dot dot. 368 00:16:03,391 --> 00:16:08,400 Na napenda sasa wanadai kwamba mimi nina kwenda kuweka thamani 1 hapa, na thamani ya 2 369 00:16:08,400 --> 00:16:11,990 hapa, inayojulikana kama x na y. 370 00:16:11,990 --> 00:16:15,300 Hivyo hivyo tu hutokea kwamba hii ni x, y ni hii. 371 00:16:15,300 --> 00:16:18,180 >> Na tu kwa baadhi ya nafasi random, kompyuta, mfumo wa uendeshaji, 372 00:16:18,180 --> 00:16:21,890 kilichotokea kwa kuweka x katika eneo simu 123. 373 00:16:21,890 --> 00:16:25,590 Na y kuishia kwenye eneo 124 - 374 00:16:25,590 --> 00:16:26,330 damn it. 375 00:16:26,330 --> 00:16:28,700 Mimi lazima fasta hii. 376 00:16:28,700 --> 00:16:34,040 Oh mtu, je, mimi kwa kweli wanataka kufanya hili? 377 00:16:34,040 --> 00:16:37,340 Ndiyo, nataka kurekebisha hii na b sahihi juu ya leo hii. 378 00:16:37,340 --> 00:16:39,950 Samahani, mpya saa hii. 379 00:16:39,950 --> 00:16:45,020 >> 127, 131, na mimi sitaki kuwa hii tata, lakini kwa nini mimi kubadili 380 00:16:45,020 --> 00:16:46,340 idadi huko? 381 00:16:46,340 --> 00:16:48,360 Sababu nataka ints kwa kweli kuwa wanne ka. 382 00:16:48,360 --> 00:16:49,810 Basi hebu kuwa super anal kuhusu hili. 383 00:16:49,810 --> 00:16:53,800 Ili kwamba kama 1 hutokea kushughulikiwa 123, 2 ni kwenda kuwa katika anuani 384 00:16:53,800 --> 00:16:55,730 127 kwa sababu ni 4 tu byes mbali. 385 00:16:55,730 --> 00:16:56,210 Hayo ni yote. 386 00:16:56,210 --> 00:16:58,640 Na tutaweza kusahau yote ya nyingine anwani katika dunia. 387 00:16:58,640 --> 00:17:03,320 >> Hivyo x ni katika eneo 123, y ni katika eneo 127. 388 00:17:03,320 --> 00:17:05,770 Na sasa, je, mimi kwa kweli wanataka kufanya? 389 00:17:05,770 --> 00:17:10,099 Wakati mimi wito wabadilishane sasa, nini hasa kinachoendelea? 390 00:17:10,099 --> 00:17:14,920 Naam, wakati mimi wito wabadilishane, mimi nina kupita katika anuani ya x na anuani ya y. 391 00:17:14,920 --> 00:17:18,540 Hivyo kwa mfano, kama hawa vipande viwili karatasi ya sasa kuwakilisha mbili 392 00:17:18,540 --> 00:17:23,510 hoja na b wabadilishane, nini mimi kwenda kuandika juu ya kwanza ya haya, 393 00:17:23,510 --> 00:17:27,720 ambayo mimi nina kwenda kuwaita rejea kama? 394 00:17:27,720 --> 00:17:30,610 >> Hasa, 123. 395 00:17:30,610 --> 00:17:31,905 Hivyo hii ni mimi kudai. 396 00:17:31,905 --> 00:17:32,955 Hii ni parameter. 397 00:17:32,955 --> 00:17:35,856 Mimi nina kuweka anuani ya x huko. 398 00:17:35,856 --> 00:17:38,152 >> Nini hiyo? 399 00:17:38,152 --> 00:17:40,890 >> Nini hiyo? 400 00:17:40,890 --> 00:17:41,190 >> Hapana, hakuna. 401 00:17:41,190 --> 00:17:41,720 Hiyo ni sawa. 402 00:17:41,720 --> 00:17:42,570 Bado ni nzuri, bado ni nzuri. 403 00:17:42,570 --> 00:17:43,530 Hivyo hii ni. 404 00:17:43,530 --> 00:17:46,240 Na sasa juu ya kipande cha pili cha karatasi, hii ni kwenda kuwa b, na nini mimi 405 00:17:46,240 --> 00:17:49,010 kwenda kuwa kuandika juu ya hii kipande cha karatasi? 406 00:17:49,010 --> 00:17:50,080 127. 407 00:17:50,080 --> 00:17:53,720 >> Hivyo kitu pekee ambacho iliyopita tangu kuwaambia yetu ya awali ya hadithi hii ni, 408 00:17:53,720 --> 00:17:58,590 badala ya literally 1 na 2, mimi nina kwenda kupita katika 123 na 127. 409 00:17:58,590 --> 00:18:02,130 Na mimi nina sasa kwenda kuweka hizi ndani ya ya sanduku hili, wote haki? 410 00:18:02,130 --> 00:18:04,640 Ili kwamba sanduku nyeusi sasa inawakilisha kazi wabadilishane. 411 00:18:04,640 --> 00:18:07,230 >> Wakati huo huo, hebu sasa kuwa na mtu kutekeleza kazi wabadilishane. 412 00:18:07,230 --> 00:18:09,090 Je mtu hapa kama kujitolea? 413 00:18:09,090 --> 00:18:09,560 Kuja juu juu. 414 00:18:09,560 --> 00:18:11,080 Nini jina lako? 415 00:18:11,080 --> 00:18:11,460 Charlie. 416 00:18:11,460 --> 00:18:12,080 Haki zote, Charlie. 417 00:18:12,080 --> 00:18:14,810 Kuja juu juu. 418 00:18:14,810 --> 00:18:17,310 >> Hivyo Charlie ni kwenda kucheza jukumu la sanduku wetu nyeusi. 419 00:18:17,310 --> 00:18:21,460 Na Charlie, nini Ningependa kufanya sasa ni kutekeleza wabadilishane katika namna 420 00:18:21,460 --> 00:18:25,320 kwamba, kutokana na wale anwani mbili, wewe walikuwa kweli kwenda 421 00:18:25,320 --> 00:18:26,330 na mabadiliko ya maadili. 422 00:18:26,330 --> 00:18:28,290 Na mimi itabidi tetesi katika sikio lako jinsi ya kuendesha TV hapa. 423 00:18:28,290 --> 00:18:29,930 >> Hivyo kwenda mbele, na wewe ni sanduku nyeusi. 424 00:18:29,930 --> 00:18:30,920 Kufikia huko. 425 00:18:30,920 --> 00:18:34,054 Maadili unaona nini kwa, na maadili unaona nini kwa ajili ya b? 426 00:18:34,054 --> 00:18:36,740 >> CHARLIE: ni 123 na b ni 127. 427 00:18:36,740 --> 00:18:37,530 >> DAVID Malan: OK, hasa. 428 00:18:37,530 --> 00:18:38,940 Sasa watakaa huko kwa muda tu. 429 00:18:38,940 --> 00:18:41,680 Jambo la kwanza ni kwenda kufanya sasa, kulingana na kanuni - ambayo 430 00:18:41,680 --> 00:18:43,220 Mimi itabidi sasa kuvuta juu ya screen - 431 00:18:43,220 --> 00:18:46,750 ni kwenda kuwa kutenga kidogo kidogo ya kumbukumbu iitwayo temp. 432 00:18:46,750 --> 00:18:48,850 Hivyo nina kwenda mbele na kukupa kwamba kumbukumbu. 433 00:18:48,850 --> 00:18:52,210 >> Hivyo hii ni kwenda kuwa kutofautiana tatu kwamba una kupatikana kwa 434 00:18:52,210 --> 00:18:54,080 wewe kuitwa temp. 435 00:18:54,080 --> 00:18:57,120 Na nini wewe ni kwenda kuandika kwenye kipande cha karatasi temp? 436 00:18:57,120 --> 00:19:02,524 437 00:19:02,524 --> 00:19:03,470 >> CHARLIE: kuyatumia, haki? 438 00:19:03,470 --> 00:19:04,790 >> DAVID Malan: OK, pia si lazima kuyatumia. 439 00:19:04,790 --> 00:19:07,230 Hivyo mstari wa kanuni kwamba nimekuwa yalionyesha upande wa kulia, 440 00:19:07,230 --> 00:19:07,900 hebu kuanza huko. 441 00:19:07,900 --> 00:19:08,890 Ni anasema nyota a. 442 00:19:08,890 --> 00:19:11,670 Hivyo kwa sasa ni kuhifadhi simu 123. 443 00:19:11,670 --> 00:19:16,660 Na tu intuitively, nini hakuwa nyota 123 mean? 444 00:19:16,660 --> 00:19:21,630 >> Lakini hasa, ikiwa ni 123, nyota maana yake nini? 445 00:19:21,630 --> 00:19:22,560 thamani ya. 446 00:19:22,560 --> 00:19:24,580 Au zaidi kawaida, kwenda huko. 447 00:19:24,580 --> 00:19:28,620 Hivyo basi mimi kupendekeza kwamba, kufanya katika mkono wako, kwenda mbele na kutibu kwamba 448 00:19:28,620 --> 00:19:29,430 kana kwamba ni ramani. 449 00:19:29,430 --> 00:19:32,940 Na kutembea mwenyewe juu ya kompyuta kumbukumbu, na kupata sisi ni nini 450 00:19:32,940 --> 00:19:36,520 katika eneo 123. 451 00:19:36,520 --> 00:19:37,720 Hasa. 452 00:19:37,720 --> 00:19:41,100 >> Hivyo tunaona katika eneo 123 ni nini, ni wazi? 453 00:19:41,100 --> 00:19:44,240 OK, hivyo nini thamani ya sasa ni wewe kwenda kuweka katika temp? 454 00:19:44,240 --> 00:19:44,750 Hasa. 455 00:19:44,750 --> 00:19:45,600 Hivyo kwenda mbele na kufanya hivyo. 456 00:19:45,600 --> 00:19:51,280 Na kuandika namba 1 katika kipande cha karatasi hiyo sasa yenye jina temp. 457 00:19:51,280 --> 00:19:53,540 >> Na sasa hatua inayofuata kwamba wewe ni kwenda kutekeleza 458 00:19:53,540 --> 00:19:54,310 ni kwenda kuwa nini. 459 00:19:54,310 --> 00:19:57,820 Naam, katika mkono wa kulia upande wa ijayo mstari wa kanuni ni nyota b. b, ya 460 00:19:57,820 --> 00:19:59,260 Bila shaka, maduka ya anwani. 461 00:19:59,260 --> 00:20:02,270 Kuwa anwani 127. 462 00:20:02,270 --> 00:20:06,620 Nyota b maana yake nini, casually akizungumza? 463 00:20:06,620 --> 00:20:08,700 >> Kwenda eneo hilo. 464 00:20:08,700 --> 00:20:14,988 Hivyo kwenda mbele na kupata sisi nini katika eneo 127. 465 00:20:14,988 --> 00:20:15,480 OK. 466 00:20:15,480 --> 00:20:19,170 Bila shaka, katika eneo 127, bado ni thamani 2. 467 00:20:19,170 --> 00:20:24,060 Basi ni nini kinachoendelea sasa katika kuhifadhi chochote ni katika eneo katika? 468 00:20:24,060 --> 00:20:26,860 Hivyo nyota njia kwenda mahali. 469 00:20:26,860 --> 00:20:29,770 Je, ni mahali? 470 00:20:29,770 --> 00:20:30,430 >> Hasa. 471 00:20:30,430 --> 00:20:34,190 Basi sasa, kama unataka kubadilisha nini katika eneo hilo - 472 00:20:34,190 --> 00:20:36,470 Mimi itabidi kwenda mbele na kukimbia Raba ni hapa. 473 00:20:36,470 --> 00:20:37,760 Na sasa kuiweka nyuma brashi. 474 00:20:37,760 --> 00:20:42,190 Nini idadi ni wewe kwenda kuandika katika sanduku tupu kwamba sasa? 475 00:20:42,190 --> 00:20:42,850 >> Hasa. 476 00:20:42,850 --> 00:20:46,470 Hivyo hii mstari wa kanuni, kuwa wazi - basi mimi pause nini Charlie kufanya na 477 00:20:46,470 --> 00:20:51,730 kumweka nje ya hapa, nini yeye tu kufanyika ni kuandika ndani ya boksi kuwa katika eneo 123 478 00:20:51,730 --> 00:20:55,150 thamani ya kwamba awali alikuwa katika b. 479 00:20:55,150 --> 00:20:59,140 Na hivyo tumekuwa sasa kutekelezwa kwa kweli line hii ya pili ya kificho. 480 00:20:59,140 --> 00:21:01,920 >> Sasa kwa bahati mbaya, kuna bado line moja iliyobaki. 481 00:21:01,920 --> 00:21:04,900 Sasa ni nini katika temp, literally? 482 00:21:04,900 --> 00:21:06,200 Ni wazi namba moja. 483 00:21:06,200 --> 00:21:07,020 Si kwamba anwani. 484 00:21:07,020 --> 00:21:09,380 Ni idadi tu, aina ya kutofautiana kutoka wiki moja. 485 00:21:09,380 --> 00:21:13,520 >> Na sasa wakati wewe kusema nyota b, kwamba maana ya kwenda b anwani, ambayo ni ya 486 00:21:13,520 --> 00:21:15,090 Bila shaka hapa. 487 00:21:15,090 --> 00:21:16,020 Hivyo mara moja kupata huko - 488 00:21:16,020 --> 00:21:18,320 Mimi itabidi kwenda mbele na kufuta nini kweli hapo - na ni nini 489 00:21:18,320 --> 00:21:20,820 kwenda kuandika sasa katika eneo 127? 490 00:21:20,820 --> 00:21:22,010 >> CHARLIE: Temp, ambayo ni moja. 491 00:21:22,010 --> 00:21:23,430 >> DAVID Malan: Temp, ambayo ni moja. 492 00:21:23,430 --> 00:21:25,670 Na nini kinatokea kwa temp katika mwisho? 493 00:21:25,670 --> 00:21:26,600 Naam, sisi kwa kweli sijui. 494 00:21:26,600 --> 00:21:27,420 Sisi si kweli huduma. 495 00:21:27,420 --> 00:21:31,090 Wakati wowote tumekuwa kutekelezwa kazi hivi sasa, yoyote vigezo mitaa una 496 00:21:31,090 --> 00:21:31,890 ni kweli mitaa. 497 00:21:31,890 --> 00:21:33,060 Na wao tu kutoweka. 498 00:21:33,060 --> 00:21:35,040 Wao ni reclaimed na uendeshaji mfumo hatimaye. 499 00:21:35,040 --> 00:21:39,800 >> Hivyo ukweli kwamba bado ana temp thamani 1 ni aina ya kimsingi 500 00:21:39,800 --> 00:21:41,150 uninteresting kwetu. 501 00:21:41,150 --> 00:21:43,100 Haki ya wote, hivyo pande zote ya applause kama tunaweza kwa Charlie. 502 00:21:43,100 --> 00:21:46,400 Vizuri sana kufanyika. 503 00:21:46,400 --> 00:21:51,520 >> Haki ya wote, hivyo nini zaidi anafanya hii ina maana tunaweza kufanya? 504 00:21:51,520 --> 00:21:54,400 Hivyo ni zamu nje ambazo tumekuwa kuwaambia chache uongo nyeupe 505 00:21:54,400 --> 00:21:55,540 kwa muda kabisa. 506 00:21:55,540 --> 00:21:59,990 Hakika, zinageuka kuwa kamba, yote ya wakati huu, si kweli 507 00:21:59,990 --> 00:22:02,190 mlolongo wa wahusika per se. 508 00:22:02,190 --> 00:22:03,980 Ni aina ya ni kwamba intuitively. 509 00:22:03,980 --> 00:22:08,270 >> Lakini kitaalam akizungumza, kamba ni data aina ya kwamba sisi alitangaza ndani ya 510 00:22:08,270 --> 00:22:12,170 Maktaba CS50 kurahisisha dunia kwa ajili ya kwanza wiki chache ya darasa. 511 00:22:12,170 --> 00:22:20,130 Nini string kweli ni ni anwani wa tabia ya mahali fulani katika RAM. 512 00:22:20,130 --> 00:22:25,530 kamba ya simu ni kweli, kama 123 au 127, kinachotokea kwa kuigawa 513 00:22:25,530 --> 00:22:28,420 ambapo kamba huanza katika kompyuta yako ya kumbukumbu. 514 00:22:28,420 --> 00:22:31,870 >> Lakini haina kuwakilisha kamba, per se, yenyewe. 515 00:22:31,870 --> 00:22:33,460 Na tunaweza kuona hii kama ifuatavyo. 516 00:22:33,460 --> 00:22:35,980 Hebu kwenda mbele na kufungua baadhi ya kanuni hiyo ni miongoni mwa 517 00:22:35,980 --> 00:22:38,340 chanzo leo kanuni mifano. 518 00:22:38,340 --> 00:22:42,225 Na mimi nina kwenda mbele na kufungua juu, hebu sema, kulinganisha-0.c. 519 00:22:42,225 --> 00:22:44,830 520 00:22:44,830 --> 00:22:48,790 Hii ni programu Buggy kwamba ni kwenda kutekelezwa kama ifuatavyo. 521 00:22:48,790 --> 00:22:49,040 >> Kwanza. 522 00:22:49,040 --> 00:22:50,420 Mimi nina kwenda kusema kitu. 523 00:22:50,420 --> 00:22:52,660 Basi mimi nina kwenda mbele na kupata kamba kutoka mtumiaji 524 00:22:52,660 --> 00:22:53,750 kwa kuwa mstari wa pili. 525 00:22:53,750 --> 00:22:55,370 Basi mimi nina kwenda kusema tena. 526 00:22:55,370 --> 00:22:57,540 Basi mimi naenda kupata mwingine kamba kutoka mtumiaji. 527 00:22:57,540 --> 00:23:00,390 >> Na notisi, mimi nina kuonyesha moja ya masharti katika variable kuitwa, na 528 00:23:00,390 --> 00:23:03,040 nyingine ya masharti hayo katika variable kuitwa t. 529 00:23:03,040 --> 00:23:07,480 Na sasa mimi nina kwenda kudai, sana sababu, kwamba kama s ni sawa sawa na t, 530 00:23:07,480 --> 00:23:08,940 masharti ni sawa. 531 00:23:08,940 --> 00:23:09,970 Unapoandika kitu kimoja. 532 00:23:09,970 --> 00:23:11,830 Mwingine, masharti ni si kitu kimoja. 533 00:23:11,830 --> 00:23:15,440 >> Baada ya yote, kama sisi pembejeo ints wawili, wawili chars, ikifungwa mbili, mara mbili mbili, yoyote ya 534 00:23:15,440 --> 00:23:18,400 aina ya data tumekuwa kuongelea hivi sasa kwa kulinganisha yao - 535 00:23:18,400 --> 00:23:22,070 wanakumbuka sisi alifanya wazi sana wakati iliyopita kwamba huna kufanya hivyo, kwa sababu 536 00:23:22,070 --> 00:23:25,840 moja ishara sawa ni ya kweli operator zoezi. 537 00:23:25,840 --> 00:23:26,820 Hivyo kwamba itakuwa mdudu. 538 00:23:26,820 --> 00:23:29,260 >> Sisi kutumia sawa sawa ishara, ambayo kwa hakika inalinganishwa 539 00:23:29,260 --> 00:23:31,050 mambo kwa usawa wa kweli. 540 00:23:31,050 --> 00:23:32,275 Lakini mimi kudai hii ni Buggy. 541 00:23:32,275 --> 00:23:37,400 Kama mimi kwenda mbele na kufanya kulinganisha sifuri, na kisha kufanya dot kufyeka kulinganisha sifuri. 542 00:23:37,400 --> 00:23:39,700 Na mimi aina katika, hebu sema, hello. 543 00:23:39,700 --> 00:23:41,590 Na kisha hebu kusema hello tena. 544 00:23:41,590 --> 00:23:46,040 Literally kitu kimoja, kompyuta madai mimi niliandika mambo mbalimbali. 545 00:23:46,040 --> 00:23:47,640 >> Sasa labda mimi tu mistyped kitu. 546 00:23:47,640 --> 00:23:49,910 Mimi itabidi aina jina langu wakati huu. 547 00:23:49,910 --> 00:23:52,580 I mean, hello. 548 00:23:52,580 --> 00:23:54,770 Hello. 549 00:23:54,770 --> 00:23:57,360 Ni tofauti kila wakati. 550 00:23:57,360 --> 00:23:58,430 >> Naam, kwa nini ni kwamba? 551 00:23:58,430 --> 00:24:00,140 Nini kweli kinachoendelea chini ya Hood? 552 00:24:00,140 --> 00:24:03,270 Naam, ni nini kweli kinachoendelea chini ya Hood ni kamba kisha 553 00:24:03,270 --> 00:24:07,410 Mimi niliandika katika wakati huo wa kwanza kwa mfano ni neno hujambo, bila shaka. 554 00:24:07,410 --> 00:24:11,660 Lakini kama sisi kuwakilisha hii chini ya kofia, kukumbuka kwamba 555 00:24:11,660 --> 00:24:13,470 kamba ni katika safu. 556 00:24:13,470 --> 00:24:15,040 Na tumekuwa alisema kama kiasi katika siku za nyuma. 557 00:24:15,040 --> 00:24:20,200 >> Hivyo kama mimi kuteka kwamba safu kama hii, mimi nina kwenda kuwakilisha kitu kabisa 558 00:24:20,200 --> 00:24:23,030 sawa na kile sisi alivyofanya wakati iliyopita. 559 00:24:23,030 --> 00:24:25,390 Na kuna kweli kitu maalum hapa, pia. 560 00:24:25,390 --> 00:24:28,090 Nini sisi kuamua ilikuwa katika mwisho wa kamba kila? 561 00:24:28,090 --> 00:24:30,760 Yeah, hii zero backslash, ambayo ni njia tu ya anayewakilisha, 562 00:24:30,760 --> 00:24:33,610 literally, 00000000. 563 00:24:33,610 --> 00:24:35,680 Nane 0 bits mfululizo. 564 00:24:35,680 --> 00:24:37,610 >> Sijui, kusema ukweli, nini baada ya hii. 565 00:24:37,610 --> 00:24:40,090 Hiyo tu rundo zaidi RAM ndani ya kompyuta yangu. 566 00:24:40,090 --> 00:24:40,970 Lakini hii ni safu. 567 00:24:40,970 --> 00:24:42,260 Kuongelea arrays kabla. 568 00:24:42,260 --> 00:24:45,010 Na sisi kawaida kuzungumzia arrays kama kuwa mahali sifuri, 569 00:24:45,010 --> 00:24:46,580 basi mmoja, basi wawili. 570 00:24:46,580 --> 00:24:47,950 Lakini hiyo ni kwa ajili ya urahisi. 571 00:24:47,950 --> 00:24:49,380 Na kwamba kabisa jamaa. 572 00:24:49,380 --> 00:24:53,010 >> Wakati wewe ni kweli kupata kumbukumbu kutoka kompyuta, ni bila shaka yoyote 573 00:24:53,010 --> 00:24:55,450 Bilioni 2 ka baadhi ya isiyo ya kawaida, uwezekano. 574 00:24:55,450 --> 00:24:59,100 Hivyo kweli chini ya Hood, muda wote huu, ndiyo. 575 00:24:59,100 --> 00:25:01,670 Hii inaweza vizuri sana kuwa mabano sifuri. 576 00:25:01,670 --> 00:25:04,780 Lakini kama wewe kuchimba hata zaidi chini ya Hood, kwamba ni kweli 577 00:25:04,780 --> 00:25:07,000 kushughulikia idadi 123. 578 00:25:07,000 --> 00:25:09,150 Hii ni anwani 124. 579 00:25:09,150 --> 00:25:11,040 Hii ni anwani 125. 580 00:25:11,040 --> 00:25:12,540 >> Na sikuwa screw up wakati huu. 581 00:25:12,540 --> 00:25:15,840 Haya sasa ni moja ka mbali kwa sababu gani? 582 00:25:15,840 --> 00:25:17,930 Jinsi kubwa ni Char? 583 00:25:17,930 --> 00:25:19,170 Char ni moja tu Byte. 584 00:25:19,170 --> 00:25:20,570 int ni kawaida ya nne ka. 585 00:25:20,570 --> 00:25:24,850 Hivyo kwamba ni kwa nini mimi alifanya hivyo 123, 127, 131 na kadhalika. 586 00:25:24,850 --> 00:25:27,560 Sasa naweza kutunza hesabu rahisi na tu kufanya pamoja na 1. 587 00:25:27,560 --> 00:25:30,510 Na hii sasa ni nini kweli kwenda juu ya chini ya Hood. 588 00:25:30,510 --> 00:25:37,760 >> Hivyo wakati wewe kutangaza kitu kama hii, kamba s, hii ni kweli - 589 00:25:37,760 --> 00:25:39,170 zinageuka - 590 00:25:39,170 --> 00:25:41,190 Char nyota. 591 00:25:41,190 --> 00:25:44,640 Nyota, bila shaka, maana anwani, aka pointer. 592 00:25:44,640 --> 00:25:46,200 Hivyo ni anuani ya kitu fulani. 593 00:25:46,200 --> 00:25:47,510 Ni nini anwani ya? 594 00:25:47,510 --> 00:25:47,760 >> Naam - 595 00:25:47,760 --> 00:25:51,680 Mimi ni mmoja tu ambaye anaweza kuona sana muhimu kumweka mimi nina kufanya, au kufikiri 596 00:25:51,680 --> 00:25:52,560 Mimi nina maamuzi. 597 00:25:52,560 --> 00:25:55,270 Hivyo kamba - 598 00:25:55,270 --> 00:25:57,180 Jambo la kusikitisha ni mimi na kufuatilia haki pale ambapo mimi 599 00:25:57,180 --> 00:25:58,100 ingeweza kuonekana kwamba. 600 00:25:58,100 --> 00:26:00,990 >> Haki wote, hivyo kamba s ni nini Mimi alitangaza hapo awali. 601 00:26:00,990 --> 00:26:04,600 Lakini zinageuka, shukrani kwa kidogo uchawi katika maktaba CS50, yote hii 602 00:26:04,600 --> 00:26:08,780 wakati kamba ana halisi imekuwa Char nyota. 603 00:26:08,780 --> 00:26:11,310 nyota tena ina maana pointer au anwani. 604 00:26:11,310 --> 00:26:14,180 ukweli kwamba ni flanking neno Char ina maana ni 605 00:26:14,180 --> 00:26:15,970 anuani ya tabia. 606 00:26:15,970 --> 00:26:23,100 >> Hivyo kama kupata kamba inaitwa, na ninapoandika katika H-E-L-L-O, sasa kupendekeza nini kupata 607 00:26:23,100 --> 00:26:27,330 kamba halisi imekuwa kurudi yote ya wakati huu, hata ingawa tumekuwa badala 608 00:26:27,330 --> 00:26:29,980 oversimplified ulimwengu? 609 00:26:29,980 --> 00:26:33,310 Je kupata kamba kweli kurudi kama kurudi thamani yake? 610 00:26:33,310 --> 00:26:35,830 611 00:26:35,830 --> 00:26:38,720 >> 123 katika kesi hii, kwa mfano. 612 00:26:38,720 --> 00:26:42,630 Tumekuwa awali alisema kwamba kupata kamba tu anarudi kamba, mlolongo wa 613 00:26:42,630 --> 00:26:43,300 wahusika. 614 00:26:43,300 --> 00:26:44,790 Lakini hiyo ni kidogo ya uongo nyeupe. 615 00:26:44,790 --> 00:26:48,010 njia kupata string kweli kazi chini ya Hood ni anapata 616 00:26:48,010 --> 00:26:48,930 kamba kutoka mtumiaji. 617 00:26:48,930 --> 00:26:51,530 Ni plops wahusika kuwa yeye au aina katika kumbukumbu. 618 00:26:51,530 --> 00:26:54,680 Ni unaweka sifuri backslash mwishoni ya wale mlolongo wa wahusika. 619 00:26:54,680 --> 00:26:57,310 >> Lakini basi ni nini kupata kamba literally kurudi? 620 00:26:57,310 --> 00:27:02,710 Ni halisi anarudi anwani ya sana kwanza ka katika RAM kwamba 621 00:27:02,710 --> 00:27:04,130 kutumika kwa nguvu kwamba. 622 00:27:04,130 --> 00:27:07,500 Na zinageuka kuwa tu na kurudi anwani moja ya 623 00:27:07,500 --> 00:27:12,120 kwanza tabia katika kamba, kwamba ni kutosha kwa ajili ya kutafuta ukamilifu wa 624 00:27:12,120 --> 00:27:12,630 kamba. 625 00:27:12,630 --> 00:27:16,930 >> Kwa maneno mengine, kupata kamba hana kurudi 123 na 124 na 125. 626 00:27:16,930 --> 00:27:19,950 Haina kunipa kwa muda mrefu orodha ya yote ya ka kwamba 627 00:27:19,950 --> 00:27:20,740 kamba wangu ni kutumia. 628 00:27:20,740 --> 00:27:22,670 Kwa sababu moja, wao ni wote nyuma kwa nyuma. 629 00:27:22,670 --> 00:27:28,160 Na mbili, ya msingi juu ya anwani ya kwanza, mimi unaweza kufikiri ambapo kamba mwisho. 630 00:27:28,160 --> 00:27:29,910 Jinsi gani? 631 00:27:29,910 --> 00:27:33,490 >> maalum null tabia, backslash sifuri mwishoni. 632 00:27:33,490 --> 00:27:35,430 Hivyo kwa maneno mengine, kama kupita kote - 633 00:27:35,430 --> 00:27:36,530 ndani ya vigezo - 634 00:27:36,530 --> 00:27:41,300 anuani ya Char, na kudhani kwamba mwisho wa kamba yoyote, 635 00:27:41,300 --> 00:27:45,040 mlolongo wa wahusika kama sisi binadamu kufikiri ya masharti, kama wewe kudhani kwamba 636 00:27:45,040 --> 00:27:48,600 mwisho wa kamba yoyote vile kuna sifuri backslash, wewe ni dhahabu. 637 00:27:48,600 --> 00:27:52,430 Kwa sababu unaweza daima kupata mwisho wa kamba. 638 00:27:52,430 --> 00:27:54,870 >> Sasa nini kweli kisha kwenda juu katika mpango huu? 639 00:27:54,870 --> 00:27:59,990 Kwa nini mpango huu, kulinganisha-0.c, Buggy? 640 00:27:59,990 --> 00:28:01,690 Nini ni kweli kuwa ikilinganishwa? 641 00:28:01,690 --> 00:28:02,420 Yeah? 642 00:28:02,420 --> 00:28:05,000 >> MWANAFUNZI: [inaudible]. 643 00:28:05,000 --> 00:28:05,730 >> DAVID Malan: Hasa. 644 00:28:05,730 --> 00:28:08,350 Ni kulinganisha maeneo ya masharti. 645 00:28:08,350 --> 00:28:12,420 Hivyo kama mtumiaji typed katika hodi mara moja, kama mimi, kumbukumbu inaweza kuishia 646 00:28:12,420 --> 00:28:13,430 kuangalia kama hii. 647 00:28:13,430 --> 00:28:18,210 Kama mtumiaji basi aina katika hodi tena, lakini kwa wito kupata kamba tena, c ni 648 00:28:18,210 --> 00:28:21,800 si hasa wajanja isipokuwa wewe kufundisha kuwa ni wajanja na kuandika code. 649 00:28:21,800 --> 00:28:22,430 >> C - 650 00:28:22,430 --> 00:28:23,860 na kompyuta kwa ujumla zaidi - 651 00:28:23,860 --> 00:28:27,370 kama wewe aina katika neno hodi tena, unajua nini wewe kwenda kupata. 652 00:28:27,370 --> 00:28:31,480 Wewe tu kwenda kupata safu ya pili ya kumbukumbu ya kwamba, ndiyo, hufanyika kuwa 653 00:28:31,480 --> 00:28:35,510 hifadhi ya H-E-L-L-O na kadhalika. 654 00:28:35,510 --> 00:28:38,240 >> Ni kwenda kuangalia huo kwa sisi binadamu, lakini hii anuani 655 00:28:38,240 --> 00:28:39,460 wanaweza kuwa 123. 656 00:28:39,460 --> 00:28:42,470 Inaweza tu hivyo kutokea kwamba mfumo wa uendeshaji ina baadhi inapatikana 657 00:28:42,470 --> 00:28:45,430 nafasi kwa mfano katika eneo - 658 00:28:45,430 --> 00:28:49,820 hebu kusema kitu kiholela, kama hii ni eneo 200. 659 00:28:49,820 --> 00:28:51,620 Na hii ni eneo 201. 660 00:28:51,620 --> 00:28:53,060 Na hii ni eneo 202. 661 00:28:53,060 --> 00:28:55,730 Sisi hatuna wazo ambapo hiyo ni kwenda kuwa katika kumbukumbu. 662 00:28:55,730 --> 00:28:59,110 >> Lakini nini maana ya hii ni kwamba ni nini kwenda kuhifadhiwa hatimaye katika s? 663 00:28:59,110 --> 00:29:00,750 simu 123. 664 00:29:00,750 --> 00:29:04,860 Nini kinaendelea kuhifadhiwa katika t, katika mfano huu holela? 665 00:29:04,860 --> 00:29:06,300 simu 200. 666 00:29:06,300 --> 00:29:11,410 Na wote kwamba ina maana basi ni wazi, 123 haina sawa 200. 667 00:29:11,410 --> 00:29:14,940 Na hivyo kama hali hii kamwe kutathmini kwa kweli. 668 00:29:14,940 --> 00:29:18,430 Kwa sababu kamba wa kupata ni kwa kutumia tofauti bonge la kumbukumbu kila wakati. 669 00:29:18,430 --> 00:29:20,360 >> Sasa tunaweza kuona hili tena katika mfano mwingine. 670 00:29:20,360 --> 00:29:23,764 Hebu kwenda mbele na kufungua nakala-0.c. 671 00:29:23,764 --> 00:29:28,770 Mimi kudai kwamba mfano huu ni kwenda kujaribu - lakini kushindwa - nakala masharti mawili 672 00:29:28,770 --> 00:29:29,910 kama ifuatavyo. 673 00:29:29,910 --> 00:29:31,730 >> Mimi nina kwenda kusema kitu kwa mtumiaji. 674 00:29:31,730 --> 00:29:34,490 Mimi kisha kwenda kupata kamba na kuiita s. 675 00:29:34,490 --> 00:29:36,400 Na sasa, mimi nina kufanya hii kuangalia hapa. 676 00:29:36,400 --> 00:29:37,990 Sisi zilizotajwa hii nyuma wakati. 677 00:29:37,990 --> 00:29:42,490 Lakini wakati ili kupata kamba kurudi null, mwingine tabia maalum, au maalum 678 00:29:42,490 --> 00:29:45,050 ishara hebu kusema. 679 00:29:45,050 --> 00:29:45,900 Kama ni nje ya kumbukumbu. 680 00:29:45,900 --> 00:29:48,970 >> Kwa mfano, kama mtumiaji ni kweli kuwa ngumu na aina mauaji 681 00:29:48,970 --> 00:29:51,220 idadi ya herufi katika keyboard na hits kuingia. 682 00:29:51,220 --> 00:29:54,580 Kama kwamba idadi ya herufi tu hawezi fit katika RAM kwa chochote mambo 683 00:29:54,580 --> 00:29:57,820 sababu, pamoja na kupata kamba nguvu vizuri sana kurudi null. 684 00:29:57,820 --> 00:30:01,080 >> Au kama programu yako yenyewe ni kufanya mengi ya mambo mengine na kuna tu 685 00:30:01,080 --> 00:30:03,790 si kumbukumbu ya kutosha kwa kamba wa kupata kufanikiwa, Ni ili mwisho 686 00:30:03,790 --> 00:30:05,240 hadi kurudi null. 687 00:30:05,240 --> 00:30:07,160 Lakini hebu kuwa sahihi zaidi kama yale hii ni. 688 00:30:07,160 --> 00:30:10,280 Je, ni s ya data aina kweli? 689 00:30:10,280 --> 00:30:11,610 Char nyota. 690 00:30:11,610 --> 00:30:14,560 >> Hivyo zinageuka sasa tunaweza peel nyuma ya safu ya null. 691 00:30:14,560 --> 00:30:17,500 Zinageuka, null ni - ndiyo, ni wazi alama maalum. 692 00:30:17,500 --> 00:30:19,190 Lakini ni nini kweli? 693 00:30:19,190 --> 00:30:25,220 Kweli, null ni ishara ya kwamba sisi binadamu kutumia kuwakilisha sifuri pia. 694 00:30:25,220 --> 00:30:29,010 >> Hivyo waandishi wa C, na kompyuta zaidi kwa ujumla, aliamua miaka iliyopita 695 00:30:29,010 --> 00:30:30,010 kwamba, unajua nini. 696 00:30:30,010 --> 00:30:34,850 Mbona sisi kuhakikisha kwamba hakuna mtumiaji data ni milele, milele, milele 697 00:30:34,850 --> 00:30:36,730 kuhifadhiwa katika sifuri bye? 698 00:30:36,730 --> 00:30:39,610 Kwa kweli, hata katika mfano wangu holela kabla, mimi si kuanza hesabu 699 00:30:39,610 --> 00:30:40,390 ka katika sifuri. 700 00:30:40,390 --> 00:30:41,540 Mimi kuanza saa moja. 701 00:30:41,540 --> 00:30:44,950 Kwa sababu nilijua watu kwamba katika ulimwengu wameamua hifadhi ya sifuri 702 00:30:44,950 --> 00:30:47,970 Byte katika RAM ya mtu yeyote kama kitu maalum. 703 00:30:47,970 --> 00:30:52,020 >> Sababu ya kuwa, wakati wowote unataka ishara kwamba kitu amekwenda vibaya 704 00:30:52,020 --> 00:30:55,960 kuhusiana na anwani, wewe akarudi null - inayojulikana kama sifuri - 705 00:30:55,960 --> 00:30:59,410 na kwa sababu unajua kwamba hakuna legit data katika anuani sifuri, ni wazi 706 00:30:59,410 --> 00:31:00,400 kwamba maana makosa. 707 00:31:00,400 --> 00:31:04,080 Na kwamba ni kwa nini sisi, kwa mkataba, angalia kwa ajili ya kitu null na kurudi 708 00:31:04,080 --> 00:31:06,260 kama moja katika kesi hizo. 709 00:31:06,260 --> 00:31:09,300 >> Hivyo kama sisi kitabu chini sasa, hii ni kisha baadhi ya kuangalia makosa, tu katika kesi 710 00:31:09,300 --> 00:31:10,610 kitu potoka na [? dhamana?] 711 00:31:10,610 --> 00:31:13,470 kabisa na kuacha mpango na kurudi mapema. 712 00:31:13,470 --> 00:31:19,030 Line hii sasa inaweza kuandikwa upya kama hii, ambayo maana yake nini? 713 00:31:19,030 --> 00:31:23,155 Upande wa kushoto, nipe mwingine pointer tabia, na kuiita t. 714 00:31:23,155 --> 00:31:26,935 Je, Mimi hifadhi ndani ya t, msingi juu ya mstari huu moja ya kanuni? 715 00:31:26,935 --> 00:31:30,950 716 00:31:30,950 --> 00:31:32,170 >> Mimi kuhifadhi mahali. 717 00:31:32,170 --> 00:31:34,742 Hasa eneo kwamba alikuwa katika s. 718 00:31:34,742 --> 00:31:39,000 Hivyo kama mtumiaji typed katika hello, na kwamba kwanza hujambo hufanyika na kuishia 719 00:31:39,000 --> 00:31:42,567 hapa, basi idadi ni 123 kwenda kuja nyuma kutoka kupata 720 00:31:42,567 --> 00:31:43,810 kamba na kuhifadhiwa - 721 00:31:43,810 --> 00:31:44,780 kama sisi alisema mapema - 722 00:31:44,780 --> 00:31:45,440 katika s. 723 00:31:45,440 --> 00:31:50,560 >> Wakati mimi sasa kutangaza mwingine pointer t Char na simu yake, ni nini idadi 724 00:31:50,560 --> 00:31:53,940 literally kwenda kuishia katika t kwa mujibu wa hadithi? 725 00:31:53,940 --> 00:31:55,420 Hivyo 123. 726 00:31:55,420 --> 00:32:00,310 >> Basi kitaalam sasa zote s na t ni akizungumzia halisi 727 00:32:00,310 --> 00:32:02,410 huo chunks ya kumbukumbu. 728 00:32:02,410 --> 00:32:06,140 Hivyo taarifa nini mimi kwenda kufanya sasa kwa kuthibitisha kwamba mpango huu ni Buggy. 729 00:32:06,140 --> 00:32:08,820 >> Kwanza mimi nina kwenda kudai, na f magazeti, kuyafanyia 730 00:32:08,820 --> 00:32:10,080 nakala ya kamba. 731 00:32:10,080 --> 00:32:11,660 Basi mimi naenda kufanya kidogo Hitilafu ya kuangalia. 732 00:32:11,660 --> 00:32:12,160 Mimi nina kwenda kuhakikisha. 733 00:32:12,160 --> 00:32:16,710 Hebu kuhakikisha kwamba t kamba ni saa angalau zaidi ya sifuri kwa urefu, 734 00:32:16,710 --> 00:32:19,190 hivyo kuna tabia ya baadhi ya huko kwa kweli capitalize. 735 00:32:19,190 --> 00:32:22,840 >> Na basi unaweza kukumbuka hii kutokana na mifano uliopita. 736 00:32:22,840 --> 00:32:25,630 2 ya juu - ambayo ni katika faili ctype.h. 737 00:32:25,630 --> 00:32:30,800 T mabano sifuri anitiaye sifuri tabia ya t kamba. 738 00:32:30,800 --> 00:32:34,360 Na 2 ya juu ya thamani hiyo hiyo, ya Bila shaka, waongofu kwa uppercase. 739 00:32:34,360 --> 00:32:38,230 >> Hivyo intuitively, hii yalionyesha line ya maadili ni kuyafanyia kwanza 740 00:32:38,230 --> 00:32:40,250 barua katika t. 741 00:32:40,250 --> 00:32:44,485 Lakini siyo kuyafanyia, shirikishi, barua ya kwanza katika s. 742 00:32:44,485 --> 00:32:48,130 Lakini kama wewe ni kufikiri mbele, nini mimi juu ya kuona wakati mimi kuendesha mpango huu 743 00:32:48,130 --> 00:32:54,220 na magazeti nje wote awali, s, na nakala kinachojulikana, t? 744 00:32:54,220 --> 00:32:55,350 >> Wao ni kweli kwenda kuwa sawa. 745 00:32:55,350 --> 00:32:56,600 Na kwa nini ni wao kwenda kuwa sawa? 746 00:32:56,600 --> 00:32:58,970 747 00:32:58,970 --> 00:33:01,020 Wao ni wawili akizungumzia hasa kitu kimoja. 748 00:33:01,020 --> 00:33:01,610 Basi hebu kufanya hili. 749 00:33:01,610 --> 00:33:03,160 >> Kufanya nakala sifuri. 750 00:33:03,160 --> 00:33:04,070 Inaandaa OK. 751 00:33:04,070 --> 00:33:06,500 Basi mimi kukimbia nakala sifuri. 752 00:33:06,500 --> 00:33:10,110 Hebu aina kitu kama hujambo katika lowercase wote kisha hit kuingia. 753 00:33:10,110 --> 00:33:16,520 Na ni madai kwamba wote ya awali na nakala ni kweli kufanana. 754 00:33:16,520 --> 00:33:17,920 >> Basi nini hasa kilichotokea hapa? 755 00:33:17,920 --> 00:33:20,100 Hebu redraw picha hii tu kuwaambia hadithi katika 756 00:33:20,100 --> 00:33:21,340 njia tofauti kidogo. 757 00:33:21,340 --> 00:33:26,060 Nini kweli kinachoendelea chini ya kofia wakati mimi kutangaza kitu kama 758 00:33:26,060 --> 00:33:30,410 Char kuanza s, au kamba s, I am kupata pointer - 759 00:33:30,410 --> 00:33:33,090 ambayo hutokea kwa kuwa wanne ka katika appliance CS50 760 00:33:33,090 --> 00:33:34,410 na katika mengi ya kompyuta. 761 00:33:34,410 --> 00:33:36,008 Na mimi naenda kuwaita hii s. 762 00:33:36,008 --> 00:33:39,810 Na hii sasa ina baadhi ya thamani haijulikani. 763 00:33:39,810 --> 00:33:43,900 >> Wakati wewe kutangaza kutofautiana, isipokuwa wewe mwenyewe kuweka thamani pale, ambao 764 00:33:43,900 --> 00:33:44,570 anajua kuna nini huko. 765 00:33:44,570 --> 00:33:48,110 Ni inaweza kuwa baadhi ya mlolongo random ya bits kutoka utekelezaji uliopita. 766 00:33:48,110 --> 00:33:52,490 Hivyo wakati mimi, katika line yangu ya maadili ya kufanya kupata kamba, na kisha kuhifadhi kurudi 767 00:33:52,490 --> 00:33:54,800 thamani katika s kupata kamba namna fulani - 768 00:33:54,800 --> 00:33:58,520 na hatimaye tutaweza peel nyuma jinsi kupata kamba kazi, kwa namna fulani kutenga 769 00:33:58,520 --> 00:34:00,480 safu kwamba pengine inaonekana kidogo kama hii. 770 00:34:00,480 --> 00:34:05,390 H-E-L-L-O, backslash sifuri. 771 00:34:05,390 --> 00:34:09,510 >> Hebu tuseme kwamba hii ni anwani 123 tu kwanza msimamo. 772 00:34:09,510 --> 00:34:13,000 Hivyo kupata faida kamba, katika yalionyesha line huko, kuirudisha 773 00:34:13,000 --> 00:34:15,000 idadi sisi alisema, 123. 774 00:34:15,000 --> 00:34:17,420 Hivyo kile kweli inakwenda ndani ya s hapa? 775 00:34:17,420 --> 00:34:26,590 >> Naam, ni nini kweli inakwenda ndani ya s ni 123. 776 00:34:26,590 --> 00:34:29,250 Lakini kusema ukweli, mimi nina kupata kidogo kuchanganyikiwa na wote wa anwani hizi, 777 00:34:29,250 --> 00:34:30,320 wote wa namba hizi kiholela. 778 00:34:30,320 --> 00:34:32,290 123, 124, 127. 779 00:34:32,290 --> 00:34:34,570 Basi hebu kweli kurahisisha dunia kidogo. 780 00:34:34,570 --> 00:34:38,800 >> Tunapozungumzia kuhusu kuyatumia, kusema ukweli, kwa sisi binadamu, ambaye heck anayejali ambapo 781 00:34:38,800 --> 00:34:39,870 mambo ni katika kumbukumbu? 782 00:34:39,870 --> 00:34:41,080 Hiyo kabisa holela. 783 00:34:41,080 --> 00:34:43,370 Ni kwenda itategemea jinsi kiasi RAM mtumiaji ana. 784 00:34:43,370 --> 00:34:46,590 Ni kwenda hutegemea wakati katika siku wewe kukimbia mpango, pengine, na 785 00:34:46,590 --> 00:34:48,250 nini pembejeo user anakupa. 786 00:34:48,250 --> 00:34:50,060 Sisi ni makao juu ya maelezo muhimu. 787 00:34:50,060 --> 00:34:54,230 >> Hivyo abstract hebu mbali na kusema kwamba, wakati kukimbia mstari wa kanuni kama hii, 788 00:34:54,230 --> 00:34:57,320 Char nyota s anapata kurudi thamani ya kamba wa kupata. 789 00:34:57,320 --> 00:35:02,720 Mbona sisi badala tu kuteka nini sisi kuweka wito pointer kama ingawa ni 790 00:35:02,720 --> 00:35:04,140 akionyesha kitu? 791 00:35:04,140 --> 00:35:07,000 Hivyo mimi kudai kwamba sasa s hadi kuna pointer - 792 00:35:07,000 --> 00:35:08,480 chini ya Hood ni anwani. 793 00:35:08,480 --> 00:35:11,330 Lakini ni tu akizungumzia Byte ya kwanza katika 794 00:35:11,330 --> 00:35:12,780 kamba kwamba imekuwa akarudi. 795 00:35:12,780 --> 00:35:16,710 >> Kama mimi sasa kurudi katika kanuni hapa, nini kinaendelea katika mstari huu? 796 00:35:16,710 --> 00:35:20,020 Naam, katika mstari huu yalionyesha sasa, Mimi kutangaza inaonekana mwingine 797 00:35:20,020 --> 00:35:21,070 variable kuitwa t. 798 00:35:21,070 --> 00:35:25,700 Lakini pia ni pointer, hivyo mimi nina kwenda kuteka ni kama, katika nadharia, halisi 799 00:35:25,700 --> 00:35:26,710 huo ukubwa sanduku. 800 00:35:26,710 --> 00:35:28,160 Na mimi nina kwenda kwa simu yake t. 801 00:35:28,160 --> 00:35:33,500 >> Na sasa kama sisi kurudi nyuma kwa kificho tena, wakati mimi kuhifadhi s ndani ya t, 802 00:35:33,500 --> 00:35:36,920 nini mimi kitaalam kuweka ndani ya t? 803 00:35:36,920 --> 00:35:39,350 Vizuri kitaalam, hii mara 123 ya simu. 804 00:35:39,350 --> 00:35:42,270 Hivyo kweli mimi lazima kuandika 123 ya simu huko. 805 00:35:42,270 --> 00:35:43,900 Lakini hebu kuchukua ni ngazi ya juu. 806 00:35:43,900 --> 00:35:48,090 t, ikiwa tu ni pointer, intuitively, ni hivyo tu. 807 00:35:48,090 --> 00:35:49,800 Hayo ni yote hiyo ni kuwa kuhifadhiwa katika huko. 808 00:35:49,800 --> 00:35:54,970 >> Hivyo sasa katika mistari ya mwisho ya kuvutia wa kanuni, wakati mimi kwa kweli kwenda juu 809 00:35:54,970 --> 00:36:00,680 kuyafanyia tabia sifuri katika t, ni nini kinaendelea? 810 00:36:00,680 --> 00:36:06,310 Naam, t mabano sifuri sasa akizungumzia kwa nini tabia, labda? 811 00:36:06,310 --> 00:36:07,460 >> Ni akizungumzia h. 812 00:36:07,460 --> 00:36:08,870 Kwa sababu t mabano sifuri - 813 00:36:08,870 --> 00:36:12,490 kukumbuka, hii ni ya zamani syntax. t bracket sifuri tu ina maana kama t ni kamba, t 814 00:36:12,490 --> 00:36:15,590 bracket sifuri ina maana kupata sifuri tabia kwa nguvu kwamba. 815 00:36:15,590 --> 00:36:18,650 Hivyo kile kwamba kweli ina maana ni kwenda safu hii - 816 00:36:18,650 --> 00:36:21,520 na ndiyo, hii inaweza kuwa 123, hii inaweza kuwa 124. 817 00:36:21,520 --> 00:36:22,790 Lakini zote ni jamaa, kukumbuka. 818 00:36:22,790 --> 00:36:25,640 Wakati wowote kuzungumza juu ya safu, tuna faida ya kuzungumza juu ya 819 00:36:25,640 --> 00:36:27,000 jamaa fahirisi. 820 00:36:27,000 --> 00:36:31,120 >> Na hivyo sasa tunaweza tu kudhani kwamba t mabano sifuri ni h. 821 00:36:31,120 --> 00:36:35,090 Hivyo kama mimi wito 2 ya juu juu yake, nini kwamba kweli kufanya ni kuwekeza 822 00:36:35,090 --> 00:36:38,290 h lowercase kwa uppercase H. Lakini bila shaka, ni nini s? 823 00:36:38,290 --> 00:36:41,010 Ni akizungumzia kamba huo darn. 824 00:36:41,010 --> 00:36:44,200 >> Hivyo hii ni kwamba wote ya kinachotokea katika kanuni hii hadi sasa. 825 00:36:44,200 --> 00:36:45,960 Basi nini basi maana? 826 00:36:45,960 --> 00:36:48,300 Jinsi gani sisi kurekebisha matatizo haya mawili? 827 00:36:48,300 --> 00:36:50,870 Jinsi gani sisi kulinganisha na masharti halisi? 828 00:36:50,870 --> 00:36:53,720 >> Vizuri intuitively, jinsi gani wewe kwenda juu ya kulinganisha mbili 829 00:36:53,720 --> 00:36:55,090 masharti kwa usawa wa kweli? 830 00:36:55,090 --> 00:36:58,920 831 00:36:58,920 --> 00:37:00,750 >> Ni nini maana kama mbili masharti ni sawa? 832 00:37:00,750 --> 00:37:04,330 Wazi si kwamba anwani zao ni sawa katika kumbukumbu, kwa sababu hiyo ni ya chini 833 00:37:04,330 --> 00:37:06,590 ngazi ya utekelezaji undani. 834 00:37:06,590 --> 00:37:08,360 Wahusika wote ni sawa. 835 00:37:08,360 --> 00:37:12,810 Hivyo basi mimi kupendekeza, na napenda kuanzisha katika toleo moja ya compare.c 836 00:37:12,810 --> 00:37:14,970 hapa, hivyo kulinganisha-1.c. 837 00:37:14,970 --> 00:37:19,590 >> Napenda kupendekeza kwamba sisi bado kupata pointer kuitwa, na kuhifadhi katika ni 838 00:37:19,590 --> 00:37:20,610 kurudi thamani ya string wa kupata. 839 00:37:20,610 --> 00:37:21,750 Hebu kufanya kitu kimoja na t. 840 00:37:21,750 --> 00:37:23,230 Hivyo hakuna wa kanuni ni tofauti. 841 00:37:23,230 --> 00:37:25,420 Mimi nina kwenda kuongeza kidogo zaidi kosa kuangalia sasa. 842 00:37:25,420 --> 00:37:29,390 Hivyo sasa kwamba sisi ni aina ya peeling nyuma hii tabaka katika CS50 wa kamba nini 843 00:37:29,390 --> 00:37:33,520 kweli ni, tunahitaji kuwa zaidi anal kuhusu kuhakikisha sisi si vibaya 844 00:37:33,520 --> 00:37:35,330 batili maadili kama null. 845 00:37:35,330 --> 00:37:36,440 >> Hivyo nina kwenda tu kuangalia. 846 00:37:36,440 --> 00:37:41,490 Kama s haina null sawa na t haina null sawa, kwamba ina maana sisi ni OK. 847 00:37:41,490 --> 00:37:44,460 Kupata kamba hakuwa screw up kupata ama ya wale masharti. 848 00:37:44,460 --> 00:37:51,270 Na unaweza labda nadhani sasa, nini haina STR CMP labda kufanya? 849 00:37:51,270 --> 00:37:52,000 Kamba kulinganisha. 850 00:37:52,000 --> 00:37:55,470 >> Hivyo kama wewe wameweza mpango java kabla, hii ni kama njia sawa katika 851 00:37:55,470 --> 00:37:56,490 kamba darasa. 852 00:37:56,490 --> 00:37:57,890 Lakini kwa wale ambao hawana iliyowekwa mbele, 853 00:37:57,890 --> 00:37:59,320 hii ni kazi c. 854 00:37:59,320 --> 00:38:02,180 Hutokea kwa kuja katika faili inayoitwa string.h. 855 00:38:02,180 --> 00:38:03,830 Hiyo ambapo ni alitangaza. 856 00:38:03,830 --> 00:38:05,110 >> Na kamba kulinganisha - 857 00:38:05,110 --> 00:38:07,530 Mimi kwa kweli kusahau matumizi yake, lakini kamwe akili kwamba. 858 00:38:07,530 --> 00:38:10,470 Kumbuka kwamba tunaweza kufanya mtu, koroga kulinganisha. 859 00:38:10,470 --> 00:38:12,590 Na hii ni kwenda kuleta Linux programmers mwongozo. 860 00:38:12,590 --> 00:38:14,060 Na ni, kusema ukweli, kidogo fumbo. 861 00:38:14,060 --> 00:38:15,270 Lakini mimi naona hapa kwamba, yep. 862 00:38:15,270 --> 00:38:17,570 Nina kuingiza string.h. 863 00:38:17,570 --> 00:38:20,590 >> Na inasema hapa chini ya maelezo, " kamba kulinganisha kazi inalinganishwa 864 00:38:20,590 --> 00:38:24,560 masharti mawili S1 na S2 ". Na S1 na S2 inaonekana ni mbili 865 00:38:24,560 --> 00:38:26,120 hoja kupita in 866 00:38:26,120 --> 00:38:28,650 Mimi si kweli kukumbuka kile const ni, lakini sasa taarifa - 867 00:38:28,650 --> 00:38:31,480 na unaweza kuona hii tayari wakati wameweza kutumia kurasa mtu kama wewe 868 00:38:31,480 --> 00:38:32,390 kuwa ni wote - 869 00:38:32,390 --> 00:38:36,220 kwamba nyota Char ni sawa na kamba. 870 00:38:36,220 --> 00:38:40,440 >> Hivyo inalinganishwa masharti mawili, S1 na S2, na kuirudisha integer chini 871 00:38:40,440 --> 00:38:44,930 zaidi au sawa na au zaidi ya sifuri kama S1 ni kupatikana, kwa mtiririko huo, kwa kuwa 872 00:38:44,930 --> 00:38:47,450 chini ya, au mechi, au kuwa zaidi ya S2. 873 00:38:47,450 --> 00:38:51,220 Hiyo ni njia tu ngumu sana ya kusema kwamba string kulinganisha anarudi 874 00:38:51,220 --> 00:38:55,760 sifuri kama mbili masharti ni shirikishi kufanana, tabia kwa 875 00:38:55,760 --> 00:38:57,120 tabia kwa ajili ya tabia. 876 00:38:57,120 --> 00:38:59,970 >> Kuirudisha simu hasi kama s, alphabetically, zinatakiwa 877 00:38:59,970 --> 00:39:01,010 kuja kabla ya t. 878 00:39:01,010 --> 00:39:05,300 Au anarudi idadi chanya kama s zinatakiwa kuja baada ya t 879 00:39:05,300 --> 00:39:06,170 alphabetically. 880 00:39:06,170 --> 00:39:08,360 Hivyo, pamoja na kazi hii rahisi, inaweza wewe, kwa mfano, aina 881 00:39:08,360 --> 00:39:09,770 nzima rundo la maneno? 882 00:39:09,770 --> 00:39:13,984 >> Hivyo katika toleo hili jipya, mimi naenda kwenda mbele na kufanya compare1. 883 00:39:13,984 --> 00:39:15,750 Dot kufyeka kulinganisha moja. 884 00:39:15,750 --> 00:39:18,030 Mimi itabidi aina katika hujambo katika kesi zote za chini. 885 00:39:18,030 --> 00:39:20,300 Mimi naenda aina katika hujambo katika lowercase yote tena. 886 00:39:20,300 --> 00:39:23,340 Na nashiriki sasa anatambua Mimi niliandika kitu kimoja. 887 00:39:23,340 --> 00:39:27,520 >> Wakati huo huo, kama mimi aina katika hodi katika chini kesi na na HELLO katika kesi ya juu 888 00:39:27,520 --> 00:39:29,710 kulinganisha yao, mimi niliandika mambo tofauti. 889 00:39:29,710 --> 00:39:32,530 Kwa sababu si tu ni anwani tofauti, lakini sisi ni kulinganisha 890 00:39:32,530 --> 00:39:35,350 tofauti wahusika tena na tena. 891 00:39:35,350 --> 00:39:37,320 >> Naam hebu kwenda moja na kurekebisha nyingine tatizo sasa. 892 00:39:37,320 --> 00:39:41,590 Napenda kufungua toleo moja ya nakala, ambayo sasa unashughulikia 893 00:39:41,590 --> 00:39:42,900 suala hili kama ifuatavyo. 894 00:39:42,900 --> 00:39:45,650 Na hii moja kwenda kuangalia kidogo ngumu zaidi. 895 00:39:45,650 --> 00:39:49,320 Lakini kama wewe kufikiri kuhusu nini tatizo sisi haja ya kutatua, hopefully hii itakuwa 896 00:39:49,320 --> 00:39:51,870 wazi katika muda tu sasa. 897 00:39:51,870 --> 00:39:57,280 >> Hivyo hii mstari wa kwanza, char kuanza t, katika layman suala inaweza kupendekeza mtu 898 00:39:57,280 --> 00:39:59,450 nini mstari huu hapa maana yake? 899 00:39:59,450 --> 00:40:01,050 Char nyota t, nini ni kwamba kufanya? 900 00:40:01,050 --> 00:40:06,660 901 00:40:06,660 --> 00:40:07,210 >> Nzuri. 902 00:40:07,210 --> 00:40:09,500 Kujenga pointer baadhi doa katika kumbukumbu. 903 00:40:09,500 --> 00:40:10,930 Na napenda kuburudisha ni kidogo kidogo. 904 00:40:10,930 --> 00:40:17,180 Kutangaza variable kwamba mapenzi kuhifadhi anuani ya baadhi Char katika kumbukumbu, tu 905 00:40:17,180 --> 00:40:18,480 kuwa zaidi kidogo sahihi. 906 00:40:18,480 --> 00:40:21,210 >> OK, hivyo sasa kwenye upande wa kulia, nimekuwa kamwe kuona moja ya kazi hizi 907 00:40:21,210 --> 00:40:22,660 kabla, malloc. 908 00:40:22,660 --> 00:40:26,980 Lakini, nini kinaweza kuwa na maana? 909 00:40:26,980 --> 00:40:28,050 Mgao wa kumbukumbu. 910 00:40:28,050 --> 00:40:29,410 Kumbukumbu mgao. 911 00:40:29,410 --> 00:40:33,050 >> Hivyo ni zamu nje, hadi sasa, sisi si kweli alikuwa na njia ya nguvu ya 912 00:40:33,050 --> 00:40:36,210 kuuliza mfumo wa uendeshaji, kunipatia kumbukumbu. 913 00:40:36,210 --> 00:40:39,980 Badala yake, sasa tuna kazi kuitwa malloc kwamba gani hasa kwamba. 914 00:40:39,980 --> 00:40:42,960 Hata ingawa hii ni kidogo ya ovyo sasa hivi, taarifa kwamba katika 915 00:40:42,960 --> 00:40:46,200 kati ya mabano mbili ni kwenda tu kuwa na idadi. 916 00:40:46,200 --> 00:40:48,510 Ambapo nimekuwa typed katika swali alama unaweza kuwa idadi. 917 00:40:48,510 --> 00:40:51,020 >> Na kwamba idadi hiyo ina maana, nipe ka 10. 918 00:40:51,020 --> 00:40:52,320 Nipe ka 20. 919 00:40:52,320 --> 00:40:53,820 Nipe ka 100. 920 00:40:53,820 --> 00:40:56,500 Na malloc kufanya bora zake kwa kuuliza mfumo wa uendeshaji - 921 00:40:56,500 --> 00:40:57,630 Linux, katika kesi hii - 922 00:40:57,630 --> 00:40:59,630 hey, ni zao 100 ka ya RAM inapatikana? 923 00:40:59,630 --> 00:41:04,320 Kama ni hivyo, kurudi ka wale kwangu kwa kurudi anuani ambayo ya 924 00:41:04,320 --> 00:41:06,610 wale ka, labda? 925 00:41:06,610 --> 00:41:07,610 sana kwanza moja. 926 00:41:07,610 --> 00:41:10,460 >> Hivyo hapa pia - na hii ni iliyoko katika C, wakati wowote wewe ni 927 00:41:10,460 --> 00:41:11,680 kushughulika na anwani? 928 00:41:11,680 --> 00:41:15,830 Wewe ni karibu daima kushughulika na kwanza vile anwani, hakuna jambo gani kubwa 929 00:41:15,830 --> 00:41:19,490 chunk ya kumbukumbu wewe ni kuwa mitupu nyuma, hivyo kusema. 930 00:41:19,490 --> 00:41:20,880 >> Basi hebu kupiga mbizi katika hapa. 931 00:41:20,880 --> 00:41:23,940 Mimi ni kujaribu kutenga jinsi wengi ka, hasa? 932 00:41:23,940 --> 00:41:24,080 Vizuri. 933 00:41:24,080 --> 00:41:26,090 Urefu wa kamba s - hebu kufanya mfano halisi. 934 00:41:26,090 --> 00:41:30,700 Kama s ni hello, H-E-L-L-O, nini urefu wa kamba s, ni wazi? 935 00:41:30,700 --> 00:41:32,010 Hivyo ni tano. 936 00:41:32,010 --> 00:41:34,590 Lakini mimi nina kufanya 1 pamoja na kwamba, kwa nini? 937 00:41:34,590 --> 00:41:37,700 Kwa nini mimi nataka ka sita badala ya tano? 938 00:41:37,700 --> 00:41:38,790 tabia null. 939 00:41:38,790 --> 00:41:41,210 >> Mimi si wanataka kuondoka mbali hii maalum null tabia. 940 00:41:41,210 --> 00:41:45,160 Kwa sababu kama mimi kufanya nakala ya Habari na tu kufanya H-E-L-L-O, lakini mimi si kuweka 941 00:41:45,160 --> 00:41:50,160 kwamba tabia maalum, kompyuta wanaweza kuwa na, kwa bahati, backslash 942 00:41:50,160 --> 00:41:51,730 sifuri pale kwa ajili yangu. 943 00:41:51,730 --> 00:41:55,570 Na hivyo kama mimi kujaribu kufikiri urefu wa nakala, mimi kufikiri kwamba 944 00:41:55,570 --> 00:41:59,360 ni 20 wahusika kwa muda mrefu, au milioni wahusika kwa muda mrefu kama mimi tu kutokea kamwe 945 00:41:59,360 --> 00:42:01,050 kuikumba sifuri backslash. 946 00:42:01,050 --> 00:42:05,780 >> Hivyo tunahitaji sita ka kuhifadhi H-E-L-L-O, backslash sifuri. 947 00:42:05,780 --> 00:42:07,870 Na kisha hii ni kuwa super anal. 948 00:42:07,870 --> 00:42:10,700 Tuseme kwamba mimi kusahau yale ukubwa wa Char ni. 949 00:42:10,700 --> 00:42:12,020 Sisi kuendelea kusema ni moja Byte. 950 00:42:12,020 --> 00:42:12,860 Na ni kawaida ni. 951 00:42:12,860 --> 00:42:15,425 Katika nadharia, inaweza kuwa kitu tofauti, juu ya Mac tofauti au 952 00:42:15,425 --> 00:42:16,250 tofauti PC. 953 00:42:16,250 --> 00:42:19,650 >> Hivyo ni zamu nje kuna operator hii kuitwa sizeof kwamba kama wewe kupita 954 00:42:19,650 --> 00:42:22,680 jina la aina data - kama Char, au int, au kuelea - 955 00:42:22,680 --> 00:42:26,930 itakuambia, dynamically, wangapi ka Char inachukua hadi juu ya hii 956 00:42:26,930 --> 00:42:28,090 hasa kompyuta. 957 00:42:28,090 --> 00:42:31,360 >> Hivyo hii ni ufanisi tu kama kusema mara 1 au 958 00:42:31,360 --> 00:42:32,440 mara kitu. 959 00:42:32,440 --> 00:42:36,340 Lakini mimi nina kufanya hivyo tu kuwa super anal, kwamba tu katika kesi Char hutofautiana 960 00:42:36,340 --> 00:42:40,610 kwenye kompyuta yako dhidi ya mgodi, kwa njia hii math daima kwenda kuangalia nje. 961 00:42:40,610 --> 00:42:43,720 >> Mwisho, chini hapa mimi kuangalia kwa null, ambayo daima ni mazoezi mazuri - tena, 962 00:42:43,720 --> 00:42:44,920 wakati wowote sisi ni kushughulika na kuyatumia. 963 00:42:44,920 --> 00:42:47,520 Kama malloc hakuwa na uwezo wa kutoa mimi sita byes - ambayo ni 964 00:42:47,520 --> 00:42:49,210 uwezekano, lakini tu katika kesi - 965 00:42:49,210 --> 00:42:50,730 kurudi moja mara moja. 966 00:42:50,730 --> 00:42:53,290 Na sasa, kwenda mbele na nakala kamba kama ifuatavyo. 967 00:42:53,290 --> 00:42:57,240 Na hii ni ukoo syntax, angalau katika nafasi tofauti. 968 00:42:57,240 --> 00:43:01,210 >> Mimi nina kwenda mbele na kupata kamba urefu wa s na kuhifadhi katika n. 969 00:43:01,210 --> 00:43:06,620 Mimi kisha kwenda iterate kutoka i sawa sifuri hadi na pamoja n, 970 00:43:06,620 --> 00:43:08,410 mkubwa kuliko au sawa na. 971 00:43:08,410 --> 00:43:13,540 Hivyo kwamba katika kila iteration, mimi kuweka idh tabia ya s katika idh 972 00:43:13,540 --> 00:43:15,380 tabia ya t. 973 00:43:15,380 --> 00:43:18,190 >> Basi nini kweli kinachoendelea chini ya Hood hapa? 974 00:43:18,190 --> 00:43:22,140 Vizuri kama hii, kwa mfano, ni s - 975 00:43:22,140 --> 00:43:26,400 na mimi kuwa typed katika neno H-E-L-L-O na kuna sifuri backslash. 976 00:43:26,400 --> 00:43:29,020 Na tena, hii ni s akizungumzia hapa. 977 00:43:29,020 --> 00:43:30,830 Na hapa sasa ni t. 978 00:43:30,830 --> 00:43:34,860 >> Na hii ni akizungumzia sasa nakala ya kumbukumbu, haki? 979 00:43:34,860 --> 00:43:37,340 Malloc amenipa nzima chunk ya kumbukumbu. 980 00:43:37,340 --> 00:43:41,440 Sijui awali nini yoyote ya maeneo hayo. 981 00:43:41,440 --> 00:43:44,340 Hivyo nina kwenda kufikiria haya kama kundi zima la alama swali. 982 00:43:44,340 --> 00:43:50,190 >> Lakini kwa haraka kama mimi kuanza looping kutoka sifuri juu juu kupitia urefu wa s, t 983 00:43:50,190 --> 00:43:52,790 mabano mabano sifuri na t 1 - 984 00:43:52,790 --> 00:43:55,080 na mimi itabidi kuweka hii sasa juu ya uendeshaji - 985 00:43:55,080 --> 00:44:04,190 t mabano sifuri na s mabano sifuri maana kwamba mimi nina kwenda kuwa kuiga 986 00:44:04,190 --> 00:44:09,875 iteratively h katika hapa, E-L-L-O. Plus, kwa sababu sikuwa pamoja 987 00:44:09,875 --> 00:44:12,370 1, backslash sifuri. 988 00:44:12,370 --> 00:44:19,060 >> Hivyo sasa katika kesi ya kulinganisha-1.c, katika mwisho, kama mimi magazeti nje 989 00:44:19,060 --> 00:44:24,760 mtaji wa t, tunapaswa kuona kwamba s ni bila kubadilika. 990 00:44:24,760 --> 00:44:26,090 Hebu kwenda mbele sasa na kufanya hii. 991 00:44:26,090 --> 00:44:28,630 Hivyo kufanya copy1. 992 00:44:28,630 --> 00:44:30,860 Dot kufyeka copy1. 993 00:44:30,860 --> 00:44:33,670 Mimi naenda aina katika hello, kuingia. 994 00:44:33,670 --> 00:44:37,430 Na sasa taarifa, tu nakala imekuwa mtaji. 995 00:44:37,430 --> 00:44:40,890 Kwa sababu mimi kweli kuwa mbili chunks ya kumbukumbu. 996 00:44:40,890 --> 00:44:44,390 >> Kwa bahati mbaya, unaweza kufanya baadhi pretty mbaya na pretty hatari mambo hapa. 997 00:44:44,390 --> 00:44:49,290 Hebu vuta hadi mfano hapa sasa, ambayo inatupa mfano wa wachache 998 00:44:49,290 --> 00:44:51,540 tofauti mistari. 999 00:44:51,540 --> 00:44:56,040 Hivyo tu intuitively hapa, mstari wa kwanza ya maadili, int nyota x, ni kutangaza 1000 00:44:56,040 --> 00:44:57,340 variable kuitwa x. 1001 00:44:57,340 --> 00:44:58,810 Na nini aina data ya kutofautiana kwamba? 1002 00:44:58,810 --> 00:45:01,820 1003 00:45:01,820 --> 00:45:04,290 Nini data aina ya kutofautiana kwamba? 1004 00:45:04,290 --> 00:45:06,980 Hiyo ilikuwa si cliffhanger. 1005 00:45:06,980 --> 00:45:08,350 >> aina ya data ni int nyota. 1006 00:45:08,350 --> 00:45:12,600 Hivyo nini maana gani? x mapenzi kuhifadhi anwani ya int. 1007 00:45:12,600 --> 00:45:13,520 Rahisi kama hiyo. 1008 00:45:13,520 --> 00:45:16,220 Y ni kwenda kuhifadhi anuani ya int. 1009 00:45:16,220 --> 00:45:18,390 Ni nini mstari wa tatu ya maadili ya kufanya huko? 1010 00:45:18,390 --> 00:45:21,850 Ni kugawa ngapi ka, uwezekano mkubwa zaidi? 1011 00:45:21,850 --> 00:45:22,350 Nne. 1012 00:45:22,350 --> 00:45:25,460 Sababu ya ukubwa wa int ni ujumla nne, malloc ya nne inatoa 1013 00:45:25,460 --> 00:45:29,950 mimi nyuma anuani ya chunk ya kumbukumbu, ya kwanza ya ka ambaye ni 1014 00:45:29,950 --> 00:45:32,110 kuhifadhiwa sasa katika x. 1015 00:45:32,110 --> 00:45:34,410 >> Sasa sisi ni kusonga kidogo haraka. 1016 00:45:34,410 --> 00:45:35,760 Nyota x maana yake nini? 1017 00:45:35,760 --> 00:45:38,480 1018 00:45:38,480 --> 00:45:42,590 Ina maana kwamba kwenda anuani na kuweka nini idadi huko? 1019 00:45:42,590 --> 00:45:43,870 Kuweka namba 42 huko. 1020 00:45:43,870 --> 00:45:47,590 Nyota y ina maana kwenda kwa nini saa y na kuweka namba 13 huko. 1021 00:45:47,590 --> 00:45:48,600 >> Lakini kusubiri dakika. 1022 00:45:48,600 --> 00:45:51,640 Je, ni katika y wakati huu? 1023 00:45:51,640 --> 00:45:54,950 Nini anwani ni y hifadhi? 1024 00:45:54,950 --> 00:45:55,770 Hatujui, haki? 1025 00:45:55,770 --> 00:45:59,230 Sisi kamwe mara moja kutumia zoezi operator kuwashirikisha y. 1026 00:45:59,230 --> 00:46:03,370 Hivyo y kama alitangaza juu ya mstari wa pili wa code ni baadhi tu ya thamani ya takataka, kubwa 1027 00:46:03,370 --> 00:46:04,760 alama ya kuuliza hivyo kusema. 1028 00:46:04,760 --> 00:46:07,230 Ni inaweza kuwa akizungumzia nasibu na kitu chochote katika kumbukumbu, ambayo 1029 00:46:07,230 --> 00:46:08,340 ujumla ni mbaya. 1030 00:46:08,340 --> 00:46:13,540 >> Hivyo kwa haraka kama sisi hit kwamba line huko, nyota y sawa na 13, kitu mbaya, 1031 00:46:13,540 --> 00:46:17,220 kitu mbaya sana ni juu ya kutokea kwa Binky. 1032 00:46:17,220 --> 00:46:25,810 Basi hebu angalia nini kinaendelea na kuishia kinachotokea kwa Binky hapa katika dakika hii 1033 00:46:25,810 --> 00:46:26,200 au ili kuangalia. 1034 00:46:26,200 --> 00:46:26,490 >> [Video avspelning] 1035 00:46:26,490 --> 00:46:26,745 >> -Hey, Binky. 1036 00:46:26,745 --> 00:46:27,000 Kuamka. 1037 00:46:27,000 --> 00:46:29,296 Ni wakati kwa ajili ya kujifurahisha pointer. 1038 00:46:29,296 --> 00:46:30,680 >> -Ni nini hiyo? 1039 00:46:30,680 --> 00:46:31,980 Kujifunza kuhusu kuyatumia? 1040 00:46:31,980 --> 00:46:34,010 Oh, goodie. 1041 00:46:34,010 --> 00:46:37,220 >> -Naam, kupata ilianza, mimi nadhani sisi ni kwenda haja ya kuyatumia wanandoa. 1042 00:46:37,220 --> 00:46:37,930 >> -OK. 1043 00:46:37,930 --> 00:46:41,650 Kanuni hii kutenga kuyatumia mbili ambayo unaweza kumweka kwa integers. 1044 00:46:41,650 --> 00:46:43,760 >> -OK, vizuri, naona kuyatumia mbili. 1045 00:46:43,760 --> 00:46:45,850 Lakini hawana wanaonekana kuwa na akizungumzia kitu. 1046 00:46:45,850 --> 00:46:46,490 >> -Hiyo ni haki. 1047 00:46:46,490 --> 00:46:48,630 Awali, kuyatumia hawana uhakika na kitu chochote. 1048 00:46:48,630 --> 00:46:51,700 mambo uhakika na walioitwa pointees, na kuweka yao juu ni 1049 00:46:51,700 --> 00:46:52,850 tofauti hatua. 1050 00:46:52,850 --> 00:46:53,740 >> -Oh, haki, haki. 1051 00:46:53,740 --> 00:46:54,500 Nilijua kwamba. 1052 00:46:54,500 --> 00:46:56,270 pointees ni tofauti. 1053 00:46:56,270 --> 00:46:58,553 Hivyo ni jinsi gani kutenga pointee? 1054 00:46:58,553 --> 00:46:59,480 >> -OK. 1055 00:46:59,480 --> 00:47:03,707 Naam, kanuni hii kutenga integers mpya pointee, na hii sehemu seti x 1056 00:47:03,707 --> 00:47:05,520 kwa uhakika na hilo. 1057 00:47:05,520 --> 00:47:06,760 >> -Hey, kwamba inaonekana zaidi. 1058 00:47:06,760 --> 00:47:08,520 Hivyo kufanya ni kufanya kitu. 1059 00:47:08,520 --> 00:47:09,530 >> -OK. 1060 00:47:09,530 --> 00:47:14,110 Mimi itabidi dereference x pointer kuhifadhi namba 42 katika pointee wake. 1061 00:47:14,110 --> 00:47:17,660 Kwa hila hii, mimi itabidi uchawi wangu wand ya dereferencing. 1062 00:47:17,660 --> 00:47:20,695 >> Wako-uchawi wand ya dereferencing? 1063 00:47:20,695 --> 00:47:22,632 Uh, kwamba ni kubwa. 1064 00:47:22,632 --> 00:47:24,620 >> -Hii ni nini kanuni inaonekana kama. 1065 00:47:24,620 --> 00:47:27,526 Mimi itabidi kuweka idadi, na - 1066 00:47:27,526 --> 00:47:28,250 >> -Hey, kuangalia. 1067 00:47:28,250 --> 00:47:29,680 Kuna unaendelea. 1068 00:47:29,680 --> 00:47:34,520 Kufanya hivyo dereference juu ya x ifuatavyo mshale wa kupata pointee wake. 1069 00:47:34,520 --> 00:47:36,690 Katika kesi hiyo, kuhifadhi 42 huko. 1070 00:47:36,690 --> 00:47:40,890 Hey, jaribu kutumia na kuhifadhi idadi 13 kupitia pointer nyingine, y. 1071 00:47:40,890 --> 00:47:42,125 >> -OK. 1072 00:47:42,125 --> 00:47:46,810 Mimi itabidi kwenda juu hapa y na kupata namba 13 kuanzisha. 1073 00:47:46,810 --> 00:47:50,890 Na kisha kuchukua wand ya dereferencing na tu - 1074 00:47:50,890 --> 00:47:52,430 Ho! 1075 00:47:52,430 --> 00:47:53,030 >> -Oh, hey. 1076 00:47:53,030 --> 00:47:54,610 Kwamba hakuwa na kazi. 1077 00:47:54,610 --> 00:47:58,200 Kusema, Binky, sidhani dereferencing y ni wazo nzuri, 1078 00:47:58,200 --> 00:48:01,370 kwa sababu ya kuanzisha pointee ni hatua tofauti. 1079 00:48:01,370 --> 00:48:03,460 Na sidhani sisi milele alifanya hivyo. 1080 00:48:03,460 --> 00:48:03,810 >> -Hmm. 1081 00:48:03,810 --> 00:48:05,160 Hatua nzuri. 1082 00:48:05,160 --> 00:48:07,410 >> -Yeah, sisi zilizotengwa y pointer. 1083 00:48:07,410 --> 00:48:10,045 Lakini sisi kamwe kuweka kwa uhakika na pointee. 1084 00:48:10,045 --> 00:48:10,490 >> -Hmm. 1085 00:48:10,490 --> 00:48:12,170 Sana mwangalifu. 1086 00:48:12,170 --> 00:48:13,790 >> -Hey, wewe ni kuangalia nzuri huko, Binky. 1087 00:48:13,790 --> 00:48:16,920 Je, unaweza kurekebisha ili y pointi kwa pointee huo kama x? 1088 00:48:16,920 --> 00:48:17,810 >> -Sure. 1089 00:48:17,810 --> 00:48:20,300 Mimi itabidi kutumia wand yangu ya uchawi wa pointer zoezi. 1090 00:48:20,300 --> 00:48:22,240 >> -Ni kwamba kwenda kuwa tatizo kama kabla? 1091 00:48:22,240 --> 00:48:22,665 >> -Hakuna. 1092 00:48:22,665 --> 00:48:24,300 Hii haina kugusa pointees. 1093 00:48:24,300 --> 00:48:27,880 Ni tu mabadiliko moja pointer kwa uhakika kwa kitu sawa kama mwingine. 1094 00:48:27,880 --> 00:48:28,970 >> -Oh, naona. 1095 00:48:28,970 --> 00:48:31,730 Sasa y pointi kwa nafasi sawa na x. 1096 00:48:31,730 --> 00:48:32,450 Hivyo kusubiri. 1097 00:48:32,450 --> 00:48:33,490 Sasa y ni fasta. 1098 00:48:33,490 --> 00:48:34,630 Ina pointee. 1099 00:48:34,630 --> 00:48:36,520 Hivyo unaweza kujaribu wand ya dereferencing tena 1100 00:48:36,520 --> 00:48:39,200 kutuma 13 juu. 1101 00:48:39,200 --> 00:48:39,840 >> -OK. 1102 00:48:39,840 --> 00:48:41,570 Hapa unaendelea. 1103 00:48:41,570 --> 00:48:42,870 >> -Hey, kuangalia kwamba. 1104 00:48:42,870 --> 00:48:44,320 Sasa dereferencing kazi juu y. 1105 00:48:44,320 --> 00:48:47,020 Na kwa sababu kuyatumia wanashiriki kwamba pointee mmoja, wao 1106 00:48:47,020 --> 00:48:48,585 wote kuona 13. 1107 00:48:48,585 --> 00:48:49,040 >> -Yeah. 1108 00:48:49,040 --> 00:48:49,670 Kugawana. 1109 00:48:49,670 --> 00:48:50,380 Chochote. 1110 00:48:50,380 --> 00:48:52,290 Hivyo ni sisi kwenda maeneo kubadili sasa? 1111 00:48:52,290 --> 00:48:52,970 >> -Oh, kuangalia. 1112 00:48:52,970 --> 00:48:54,150 Tuko nje ya muda. 1113 00:48:54,150 --> 00:48:55,200 >> -Lakini - 1114 00:48:55,200 --> 00:48:57,060 >> Kumbuka tu-tatu pointer sheria. 1115 00:48:57,060 --> 00:49:00,100 Namba moja, muundo wa msingi ni kwamba una pointer. 1116 00:49:00,100 --> 00:49:02,170 Na inaelekeza juu ya pointee. 1117 00:49:02,170 --> 00:49:04,160 Lakini pointer na pointee ni tofauti. 1118 00:49:04,160 --> 00:49:06,460 Na makosa ya kawaida ni kuanzisha pointer, lakini kwa 1119 00:49:06,460 --> 00:49:08,540 kusahau aliyopewa pointee. 1120 00:49:08,540 --> 00:49:12,460 >> Namba mbili, pointer dereferencing kuanza saa pointer na ifuatavyo yake 1121 00:49:12,460 --> 00:49:14,570 mshale juu ya kupata pointee wake. 1122 00:49:14,570 --> 00:49:18,640 Kama sisi wote kujua, hii kazi tu kama kuna ni pointee, ambayo anapata nyuma 1123 00:49:18,640 --> 00:49:19,790 kutawala namba moja. 1124 00:49:19,790 --> 00:49:23,670 >> Namba tatu, pointer zoezi inachukua moja pointer na mabadiliko yake kwa uhakika na 1125 00:49:23,670 --> 00:49:25,850 pointee huo kama pointer mwingine. 1126 00:49:25,850 --> 00:49:27,840 Hivyo baada ya kazi, kuyatumia mbili mapenzi 1127 00:49:27,840 --> 00:49:29,430 uhakika na pointee sawa. 1128 00:49:29,430 --> 00:49:31,600 Wakati mwingine kwamba wito kugawana. 1129 00:49:31,600 --> 00:49:33,430 Na kwamba wote kuna hiyo, kwa kweli. 1130 00:49:33,430 --> 00:49:33,840 Bye bye sasa. 1131 00:49:33,840 --> 00:49:34,300 >> [MWISHO video avspelning] 1132 00:49:34,300 --> 00:49:36,940 >> DAVID Malan: Hivyo zaidi juu ya kuyatumia, zaidi juu ya wiki Binky ijayo. 1133 00:49:36,940 --> 00:49:38,190 Tutaweza kuona juu ya Jumatatu. 1134 00:49:38,190 --> 00:49:42,187