1 00:00:07,590 --> 00:00:09,920 [Powered by Google Translate] DAVID J. Malan: zote haki, hii ni CS50 na hii ni 2 00:00:09,920 --> 00:00:15,250 mwisho wa Wiki 1, hivyo utafiti kadi ni katika na jumla ya idadi ya 3 00:00:15,250 --> 00:00:18,640 wanafunzi kuwa una mwaka huu ni 745. 4 00:00:18,640 --> 00:00:20,920 Na sisi ni hivyo furaha kuwa na hivyo wengi wenu katika kozi 5 00:00:20,920 --> 00:00:23,680 hii muhula, lakini hata kama kweli hii ni kubwa, 6 00:00:23,680 --> 00:00:26,090 kutambua kwamba ni mambo hayo kama chakula cha mchana Ijumaa, kama 7 00:00:26,090 --> 00:00:29,020 masaa ya ofisi, sehemu 15-mtu, na hivyo nje kwamba 8 00:00:29,020 --> 00:00:30,590 ni kweli maana ya kujenga hii ionekane zaidi 9 00:00:30,590 --> 00:00:31,140 mazingira. 10 00:00:31,140 --> 00:00:34,070 Hivyo hata ingawa tunaweza kukusanya mara moja au mbili kwa wiki, hapa katika 11 00:00:34,070 --> 00:00:36,420 Sanders, tunajua kwamba sehemu kubwa ya uzoefu wako katika kozi hii 12 00:00:36,420 --> 00:00:39,330 itakuwa sana kuwa mikono-juu ya pamoja ya wanafunzi wako 13 00:00:39,330 --> 00:00:40,730 na wafanyakazi kufundisha. 14 00:00:40,730 --> 00:00:43,960 >> Hivyo hapa sisi kwenda, Fall 2012. 15 00:00:43,960 --> 00:00:47,530 Hivyo kukumbuka kuwa wakati wa mwisho tuliishia kwenye note ya 16 00:00:47,530 --> 00:00:50,460 kutokuwa sahihi, kuzungumza juu ya uwakilishi wa idadi. 17 00:00:50,460 --> 00:00:52,950 Na sisi inaonekana katika moja ya kushindwa kwamba kilichotokea, katika 18 00:00:52,950 --> 00:00:54,920 ulimwengu halisi, wakati alikuja kutokuelewana 19 00:00:54,920 --> 00:00:55,890 jinsi ya kompyuta kazi. 20 00:00:55,890 --> 00:00:58,590 Naam, leo tutaweza kupitia upya mwingine mmoja wa wale mawazo kama 21 00:00:58,590 --> 00:01:01,410 vizuri kama kuendelea majadiliano yetu ya mteja CS50 22 00:01:01,410 --> 00:01:04,090 na C na nini maana yake kwa kweli kwa mpango. 23 00:01:04,090 --> 00:01:06,430 Lakini kwanza, michache tu ya matangazo kimbunga. 24 00:01:06,430 --> 00:01:08,930 >> Sehemu kuanza Jumapili hii, na wiki ya kwanza daima ni 25 00:01:08,930 --> 00:01:11,030 kidogo ya kuanza haraka, kwa sababu sisi tu got katika 26 00:01:11,030 --> 00:01:12,620 sehemu yako fomu. 27 00:01:12,620 --> 00:01:14,450 Sisi ni kufanya sawa, sasa, pamoja na wenzake mafundisho, sasa 28 00:01:14,450 --> 00:01:16,410 kwamba wao kujua ratiba yao, hivyo sisi ni lengo, kwa 29 00:01:16,410 --> 00:01:19,380 Jumamosi asubuhi, kufuatilia na wewe kwa sehemu yako 30 00:01:19,380 --> 00:01:20,760 zoezi na TF. 31 00:01:20,760 --> 00:01:22,770 Kutambua kwamba wao itabidi kuanza kesho, Jumapili 32 00:01:22,770 --> 00:01:24,510 au Jumatatu au Jumanne. 33 00:01:24,510 --> 00:01:27,730 Na kisha sisi mabadiliko ya malazi ya sehemu kama yanavyojitokeza 34 00:01:27,730 --> 00:01:28,690 katika siku zijazo. 35 00:01:28,690 --> 00:01:31,590 Ofisi ya masaa, wakati huo huo, ni, tena, usiku wa leo, 08:00 hadi 11, katika 36 00:01:31,590 --> 00:01:33,740 Annenberg, kama vile kesho usiku. 37 00:01:33,740 --> 00:01:36,150 Hata ingawa seti tatizo ni ujumla kutokana Alhamisi 38 00:01:36,150 --> 00:01:39,020 saa sita mchana, utambue kuwa hadi tano marehemu siku ya kutumia, 39 00:01:39,020 --> 00:01:42,430 hivyo upatikanaji wa masaa ya ofisi Alhamisi ikiwa 40 00:01:42,430 --> 00:01:45,930 wewe fedha katika moja ya siku hizo marehemu na hivyo, kuwasilisha 41 00:01:45,930 --> 00:01:47,070 kitu juu ya Ijumaa. 42 00:01:47,070 --> 00:01:50,850 Hebu zinaonyesha kwamba Scratch ni miongoni mwa furaha zaidi, miongoni mwa 43 00:01:50,850 --> 00:01:52,390 Asili muhimu zaidi tatizo seti. 44 00:01:52,390 --> 00:01:55,160 Na napenda hutegemea kwenye siku hizo marehemu, kimkakati, tu 45 00:01:55,160 --> 00:01:57,380 kwa ajili ya baadaye katika muhula wakati maisha huanza kupata njia 46 00:01:57,380 --> 00:01:59,470 na midterms na madarasa mengine. 47 00:01:59,470 --> 00:02:01,580 Tatizo Set 1, wakati huo huo, itakuwa posted kwenye kozi ya 48 00:02:01,580 --> 00:02:06,080 Tovuti hii ya Ijumaa, kama itakuwa katika kutembea mwendo wa 49 00:02:06,080 --> 00:02:08,789 kwa njia ya video, ambayo itakuwa saa 2:30 zingine juu ya Ijumaa 50 00:02:08,789 --> 00:02:11,890 na kisha posted online kwa siku ya pili. 51 00:02:11,890 --> 00:02:13,880 >> Hivyo sisi kumalizika Jumatatu. 52 00:02:13,880 --> 00:02:15,450 Nataka - kweli, mmoja kumbuka hapa. 53 00:02:15,450 --> 00:02:18,870 Kwa sababu madarasa - kwa sababu Sanders haina hasa mikopo 54 00:02:18,870 --> 00:02:22,220 yenyewe kwa kawaida & Q na kurudi vizuri sana, sisi ni 55 00:02:22,220 --> 00:02:24,030 kwenda kujaribu kitu kidogo mpya mwaka huu, ambapo 56 00:02:24,030 --> 00:02:26,160 kama wewe si vizuri kuinua mkono wako au wewe tu 57 00:02:26,160 --> 00:02:28,800 Na wala kunyanyua mkono wako katika chumba kama hii, 58 00:02:28,800 --> 00:02:30,710 tunakwenda kuwa na baadhi ya wenzake mafundisho na CAS 59 00:02:30,710 --> 00:02:33,260 Manning cs50.net/discuss wakati mihadhara. 60 00:02:33,260 --> 00:02:35,440 Hivyo kama una swali kwa sababu nilikuwa kabisa 61 00:02:35,440 --> 00:02:37,510 wazi kuhusu kitu au wewe ni curious kuhusu baadhi 62 00:02:37,510 --> 00:02:39,640 mada, jaribu posting huko. 63 00:02:39,640 --> 00:02:42,670 Tag ni pamoja na studio ya Qur'ani, na tutaweza kufanya kazi nzuri 64 00:02:42,670 --> 00:02:45,430 leo na wiki ijayo - we'll kujaribu hii nje - kwa shamba hilo 65 00:02:45,430 --> 00:02:47,990 aidha kielektroniki, online, au kama anahisi kama inavyopaswa 66 00:02:47,990 --> 00:02:50,430 kweli kulishughulikia sw masse, mmoja wa wenzake mafundisho au 67 00:02:50,430 --> 00:02:52,080 CAS itakuwa kuinua mikono yao na kuuliza 68 00:02:52,080 --> 00:02:53,480 anonymously kwa niaba yako. 69 00:02:53,480 --> 00:02:55,650 Hivyo tutaweza kutoa hii ya kujaribu na kuona jinsi vizuri kazi hii. 70 00:02:55,650 --> 00:02:58,540 Lakini, kwa njia zote, kuendelea kuinua mikono kama ungependa. 71 00:02:58,540 --> 00:03:11,420 >> Hivyo wakati wa mwisho sisi umebaini kuwa 10% au moja ya kumi si, katika 72 00:03:11,420 --> 00:03:13,840 kweli, 0.1, kama mlivyofundishwa miaka mingi iliyopita. 73 00:03:13,840 --> 00:03:15,390 Ni kwa kweli, thamani kama hii. 74 00:03:15,390 --> 00:03:16,970 Lakini si kwamba kweli kabisa, sawa? 75 00:03:16,970 --> 00:03:19,585 Sisi tu hii kikwazo katika kompyuta ambapo, kama wewe 76 00:03:19,585 --> 00:03:22,450 tu kuwa na kiasi kidogo cha kumbukumbu, RAM, au zaidi 77 00:03:22,450 --> 00:03:25,220 hasa bits, vizuri, kuna tu idadi finite 78 00:03:25,220 --> 00:03:26,980 wa mambo unaweza kuwakilisha. 79 00:03:26,980 --> 00:03:29,780 Kwa mfano, kama tuna idadi ya sifuri, na tunataka 80 00:03:29,780 --> 00:03:32,790 kuwakilisha katika binary, kwa kutumia bits nane, ambapo kidogo, 81 00:03:32,790 --> 00:03:34,710 tena, ni zero au moja, tupate 82 00:03:34,710 --> 00:03:39,240 kuiwakilisha kama 00,000,000. 83 00:03:39,240 --> 00:03:41,160 Na kwamba ni kidogo unnecessarily verbose. 84 00:03:41,160 --> 00:03:43,700 Kama ilivyo katika mfumo decimal katika ulimwengu wa kweli, 85 00:03:43,700 --> 00:03:47,040 ujumla, kama unataka kuandika 123 idadi, sisi 86 00:03:47,040 --> 00:03:52,240 binadamu pengine wala kuandika 00000123 hata ingawa, 87 00:03:52,240 --> 00:03:53,940 functionally, hiyo ni halisi idadi sawa. 88 00:03:53,940 --> 00:03:56,580 Sisi tone tu zeros kuongoza, hivyo kusema. 89 00:03:56,580 --> 00:03:58,270 >> Katika binary, tunaweza kufanya hivyo. 90 00:03:58,270 --> 00:04:01,440 Binary na sifuri, sifuri na binary ni sifuri. 91 00:04:01,440 --> 00:04:02,870 Unahitaji tu kidogo moja. 92 00:04:02,870 --> 00:04:05,020 Lakini tena, kitengo ya kawaida ya kipimo katika ulimwengu 93 00:04:05,020 --> 00:04:07,820 wa kompyuta ni ka, bits nane. 94 00:04:07,820 --> 00:04:09,720 Kwa sababu tu moja kidogo, pretty maana. 95 00:04:09,720 --> 00:04:12,020 Nane bits, si sana muhimu, lakini angalau ni zaidi 96 00:04:12,020 --> 00:04:14,280 muhimu zaidi kuliko kitengo moja ya kipimo. 97 00:04:14,280 --> 00:04:17,100 Hivyo, pamoja na bits nane, tutaweza kawaida kuwakilisha binary. 98 00:04:17,100 --> 00:04:20,459 Hivyo hapa sisi kuwa na idadi ya sifuri, moja, mbili, na kisha, kama 99 00:04:20,459 --> 00:04:24,200 Nate alivyofanya katika video yetu ya mwisho Jumatano, tunaweza kuendelea 100 00:04:24,200 --> 00:04:25,940 kuhesabu hadi saba, hadi nane. 101 00:04:25,940 --> 00:04:27,860 Na kisha kama sisi kutumia bits zaidi na zaidi, sisi 102 00:04:27,860 --> 00:04:29,880 unaweza kuhesabu hadi infinity. 103 00:04:29,880 --> 00:04:32,800 Lakini kama una idadi finite ya bits hizi, kama ni 104 00:04:32,800 --> 00:04:35,030 kesi katika mfumo kompyuta yoyote, au hata kombora 105 00:04:35,030 --> 00:04:36,670 mfumo, vizuri, hakika wewe tu 106 00:04:36,670 --> 00:04:37,900 finite kiasi cha usahihi. 107 00:04:37,900 --> 00:04:41,290 Hivyo kama unataka kuwakilisha idadi kama 0.1, vizuri, 108 00:04:41,290 --> 00:04:43,410 kompyuta ina kuchukua na kuchagua. 109 00:04:43,410 --> 00:04:45,970 Na kama ni tu ina idadi finite ya idadi inaweza 110 00:04:45,970 --> 00:04:50,490 kuwakilisha, inaweza kuja karibu na 0.1 kwa ajili yenu, lakini haiwezi 111 00:04:50,490 --> 00:04:53,730 lazima kukupa hasa thamani kwamba unataka. 112 00:04:53,730 --> 00:04:55,660 Na hii ni moja tu ya changamoto za kompyuta, 113 00:04:55,660 --> 00:04:57,090 chini ya Hood, nashiriki. 114 00:04:57,090 --> 00:04:59,110 >> Kama sisi kusonga mbele katika muhula, hizi ngazi ya chini 115 00:04:59,110 --> 00:05:02,310 maelezo pungua sana ya kuvutia, lakini kwa hakika 116 00:05:02,310 --> 00:05:05,700 maombi ya mawazo haya yanaweza kuwa na baadhi ya dunia halisi 117 00:05:05,700 --> 00:05:06,760 ramifications. 118 00:05:06,760 --> 00:05:08,190 Moja ni fun kidogo. 119 00:05:08,190 --> 00:05:12,150 Jinsi wengi umeona ajabu movie Ofisi Space? 120 00:05:12,150 --> 00:05:13,620 Kama una si, hiyo ni unofficial yako 121 00:05:13,620 --> 00:05:14,370 homework kwa wiki. 122 00:05:14,370 --> 00:05:16,730 Lakini katika Space Ofisi, wenzake katika movie kwamba kuchukua 123 00:05:16,730 --> 00:05:19,900 faida ya usahihi wazo hili, lakini kwa kweli aliiba 124 00:05:19,900 --> 00:05:21,270 ni kutoka mwingine movie kwamba unaweza kuwa na 125 00:05:21,270 --> 00:05:22,760 kuonekana, hata kabla ya miaka. 126 00:05:22,760 --> 00:05:24,920 Hivyo basi mimi kukupa sekunde chache ya trailer hii kutoka 127 00:05:24,920 --> 00:05:27,470 hii movie ajabu na hii ni mengi sana 128 00:05:27,470 --> 00:05:28,340 kimasomo husika. 129 00:05:28,340 --> 00:05:30,310 >> [Ina MOVIE] 130 00:05:30,310 --> 00:05:32,240 Kwa kweli mimi nina kuwa kukuzwa. 131 00:05:32,240 --> 00:05:33,360 Mimi unaweza mpango virusi kwamba mpasuko kwamba 132 00:05:33,360 --> 00:05:34,460 mahali mbali muda kubwa. 133 00:05:34,460 --> 00:05:35,770 Naam, jinsi gani kazi? 134 00:05:35,770 --> 00:05:37,836 Kila wakati kuna shughuli benki ambapo riba ni 135 00:05:37,836 --> 00:05:40,154 computed, kuna maelfu siku, kompyuta inaishia 136 00:05:40,154 --> 00:05:41,040 na haya FRACTIONS ya asilimia. 137 00:05:41,040 --> 00:05:43,050 Lakini mimi si kwenda kufanya kitu chochote kinyume cha sheria. 138 00:05:43,050 --> 00:05:46,730 Haramu? Samir, hii ya Kaskazini ni. 139 00:05:46,730 --> 00:05:48,010 Una kuapa kwa Mungu. 140 00:05:48,010 --> 00:05:51,870 Kama hakuna mtu anajua kuhusu jambo hili lakini sisi, wote haki? Familia, hakuna 141 00:05:51,870 --> 00:05:52,490 rafiki wa kike, hakuna. 142 00:05:52,490 --> 00:05:53,882 [Inaudible]. 143 00:05:53,882 --> 00:05:57,594 Usijali, mtu, mimi si kumwambia mtu yeyote ama. 144 00:05:57,594 --> 00:05:59,680 [MOVIE MWISHO] 145 00:05:59,680 --> 00:06:01,900 >> Haki zote, hivyo labda nimeona hii movie bora kuliko wengi 146 00:06:01,900 --> 00:06:05,530 watu hapa, lakini katika hali yoyote, virusi kwamba walikuwa 147 00:06:05,530 --> 00:06:06,400 kujaribu kujenga - 148 00:06:06,400 --> 00:06:08,410 na katika sinema, wakati wowote wao d kuwaita kitu virusi, 149 00:06:08,410 --> 00:06:09,770 ni ujumla si kweli virusi. 150 00:06:09,770 --> 00:06:11,600 Ni tu mpango kwamba mtu aliandika kufanya kitu fulani. 151 00:06:11,600 --> 00:06:13,800 Na katika kesi hii, guys walikuwa wanajaribu kuandika mpango 152 00:06:13,800 --> 00:06:16,610 kwamba alichukua faida ya kampuni yao iitwayo Innotech ya 153 00:06:16,610 --> 00:06:19,740 kompyuta mfumo, ambapo kompyuta, pia, hata wakati 154 00:06:19,740 --> 00:06:21,350 huja kwa fedha, unaweza si lazima 155 00:06:21,350 --> 00:06:23,490 kuwakilisha fedha usahihi. 156 00:06:23,490 --> 00:06:27,630 Hivyo hata ingawa unaweza kuwa na $ 0.10 katika akaunti yako ya benki, 157 00:06:27,630 --> 00:06:31,060 0.10, vizuri, kompyuta ili kweli kufikiria kuwa una 158 00:06:31,060 --> 00:06:33,560 hii senti nyingi katika akaunti yako ya benki. 159 00:06:33,560 --> 00:06:35,750 Na hivyo ni nini hawa guys walikuwa anayetaka kufanya - na wao 160 00:06:35,750 --> 00:06:38,240 aliiba wazo, zinageuka kutoka Superman III, ambapo 161 00:06:38,240 --> 00:06:41,210 Richard Pryor waliwafanyia - wao walikuwa kimsingi 162 00:06:41,210 --> 00:06:44,880 kuandika mipango kutamani kuchukua yote ya trailing 163 00:06:44,880 --> 00:06:46,930 idadi, aina ya vidogo, vidogo FRACTIONS, vidogo ya 164 00:06:46,930 --> 00:06:50,160 pennies, na wale siphoning mbali hivyo kuwa binadamu tu 165 00:06:50,160 --> 00:06:52,620 mawazo, oh, ni tu $ 0.10 huko, lakini wale wote 166 00:06:52,620 --> 00:06:54,410 trailing idadi hatimaye kuongeza up. 167 00:06:54,410 --> 00:06:57,490 Hivyo wazo ajabu na backfired hilariously katika kuwa 168 00:06:57,490 --> 00:06:58,250 Hasa filamu. 169 00:06:58,250 --> 00:07:01,800 >> Lakini katika ulimwengu wa kweli, pia, kuna mengi zaidi kuhusu 170 00:07:01,800 --> 00:07:03,190 matokeo ya aina hii ya mambo. 171 00:07:03,190 --> 00:07:05,450 Na moja ya sababu ya kupiga mbizi katika uwanja wa kompyuta 172 00:07:05,450 --> 00:07:07,620 sayansi ni, tena, applicability yake si kwa 173 00:07:07,620 --> 00:07:09,740 uhandisi sayansi peke yake, bali tu kwa 174 00:07:09,740 --> 00:07:10,650 mashamba mengine pia. 175 00:07:10,650 --> 00:07:14,760 Hivyo hii ni kuangalia chini lighthearted ya kile kinachoweza kwenda vibaya, lakini 176 00:07:14,760 --> 00:07:17,630 pia ni kabisa jicho ufunguzi, nadhani, linapokuja 177 00:07:17,630 --> 00:07:20,760 kuelewa hasa jinsi omnipresent teknolojia kama 178 00:07:20,760 --> 00:07:22,870 kompyuta na programu au siku hizi, 179 00:07:22,870 --> 00:07:23,930 katika fomu ya programu. 180 00:07:23,930 --> 00:07:26,500 Hivyo hii clip pili ni sita tu kuhusu dakika, inaendelea 181 00:07:26,500 --> 00:07:30,320 ambapo sisi kushoto mbali wakati wa mwisho, lakini inaruhusu sisi kuangalia kidogo 182 00:07:30,320 --> 00:07:33,370 zaidi katika kina katika moja vile ya masuala haya. 183 00:07:33,370 --> 00:07:35,270 Hebu ruka mbele ambapo sisi kushoto mbali, 184 00:07:35,270 --> 00:07:37,780 ambayo ilikuwa haki hapa. 185 00:07:37,780 --> 00:07:41,580 Na tuna sehemu mbili wa mbili, kwa dakika sita hapa. 186 00:07:41,580 --> 00:07:41,980 >> [PLAY MOVIE] 187 00:07:41,980 --> 00:07:45,430 Wanakumbana kisasa roketi teknolojia. 188 00:07:45,430 --> 00:07:49,280 Katika 1991, pamoja na mwanzo wa Vita ya Ghuba ya kwanza, Patriot 189 00:07:49,280 --> 00:07:51,350 kombora uzoefu aina sawa ya 190 00:07:51,350 --> 00:07:52,645 idadi uongofu tatizo. 191 00:07:52,645 --> 00:07:57,460 Na kama matokeo, watu 20, 20 American askari, waliuawa 192 00:07:57,460 --> 00:08:01,130 na juu ya 100 wengine walijeruhiwa, wakati Patriot, ambayo ilitakiwa 193 00:08:01,130 --> 00:08:03,400 na kulinda dhidi ya Scuds zinazoingia, 194 00:08:03,400 --> 00:08:06,020 alishindwa kwa moto kombora. 195 00:08:06,020 --> 00:08:09,350 >> Wakati Iraq walivamia Kuwait na Marekani ilizindua Jangwa 196 00:08:09,350 --> 00:08:13,530 Dhoruba katika 1991 mapema, Patriot kombora betri walikuwa 197 00:08:13,530 --> 00:08:16,970 uliotumika kulinda Saudi Arabia na Israeli kutoka Iraq 198 00:08:16,970 --> 00:08:19,810 Scud kombora mashambulizi. 199 00:08:19,810 --> 00:08:23,740 Patriot ni Marekani kati-mbalimbali uso-kwa-hewa mfumo, 200 00:08:23,740 --> 00:08:26,370 viwandani na kampuni Raytheon. 201 00:08:26,370 --> 00:08:30,860 ukubwa wa interceptor Patriot yenyewe, ni kuhusu 202 00:08:30,860 --> 00:08:35,650 takribani 20 miguu kwa muda mrefu na ni kizito kuhusu £ 2000. 203 00:08:35,650 --> 00:08:38,809 Na hubeba warhead ya juu - nadhani ni takribani 204 00:08:38,809 --> 00:08:40,169 £ 150. 205 00:08:40,169 --> 00:08:45,820 Na warhead yenyewe ni kulipuka high ambayo ina 206 00:08:45,820 --> 00:08:48,120 vipande ya kuzunguka. 207 00:08:48,120 --> 00:08:51,870 casing ya warhead ni iliyoundwa na kutenda kama buckshot. 208 00:08:51,870 --> 00:08:54,920 makombora ni kufanyika nne kwa kila chombo na ni 209 00:08:54,920 --> 00:08:57,850 kusafirishwa kwa Trailer nusu. 210 00:08:57,850 --> 00:09:02,940 >> Patriot kupambana kombora mfumo inakwenda nyuma angalau kwa 211 00:09:02,940 --> 00:09:05,530 Miaka 20 sasa. 212 00:09:05,530 --> 00:09:09,150 Ni mara awali iliyoundwa kama kombora hewa ulinzi kwa 213 00:09:09,150 --> 00:09:12,920 risasi chini ndege ya adui, katika Vita ya kwanza ya Ghuba. 214 00:09:12,920 --> 00:09:17,700 Wakati vita kwamba alikuja pamoja, Jeshi alitaka kuitumia kwa risasi 215 00:09:17,700 --> 00:09:19,880 chini Scuds, si ndege. 216 00:09:19,880 --> 00:09:24,860 Air Force Iraq haikuwa hivyo mengi ya tatizo, lakini Jeshi 217 00:09:24,860 --> 00:09:27,260 alikuwa na wasiwasi kuhusu Scuds. 218 00:09:27,260 --> 00:09:30,810 Na hivyo walijaribu kuboresha Patriot. 219 00:09:30,810 --> 00:09:33,770 Intercepting kombora adui kusafiri saa Mach 5 alikuwa anaenda 220 00:09:33,770 --> 00:09:35,790 ni changamoto ya kutosha. 221 00:09:35,790 --> 00:09:39,460 Lakini wakati Patriot alikimbizwa katika huduma, Jeshi 222 00:09:39,460 --> 00:09:43,730 hakuwa na ufahamu wa muundo wa Iraq kwamba alifanya yao 223 00:09:43,730 --> 00:09:46,510 Scuds karibu haiwezekani hit. 224 00:09:46,510 --> 00:09:50,040 >> Kilichotokea ni kwamba walikuwa Scuds 225 00:09:50,040 --> 00:09:51,360 kuja katika walikuwa imara. 226 00:09:51,360 --> 00:09:52,266 Walikuwa tikisika. 227 00:09:52,266 --> 00:09:56,300 Sababu ya hayo ni raia wa Iraq, ili kupata 600 228 00:09:56,300 --> 00:10:00,650 kilomita nje ya kombora kilomita 300 mbalimbali, alichukua 229 00:10:00,650 --> 00:10:02,423 uzito nje ya warhead mbele na 230 00:10:02,423 --> 00:10:03,990 alifanya warhead nyepesi. 231 00:10:03,990 --> 00:10:08,700 Hivyo sasa Patriot ya kujaribu kuja katika Scud, na zaidi ya 232 00:10:08,700 --> 00:10:11,192 wakati, idadi kubwa ya muda, ingekuwa 233 00:10:11,192 --> 00:10:13,450 tu ya kuruka kwa Scud. 234 00:10:13,450 --> 00:10:16,300 Mara tu mfumo wa Patriot waendeshaji alitambua Patriot 235 00:10:16,300 --> 00:10:20,160 amekosa lengo lake, wao detonated warhead Patriot. 236 00:10:20,160 --> 00:10:22,760 Ili kuepuka majeruhi iwezekanavyo, aliruhusiwa 237 00:10:22,760 --> 00:10:25,100 kuanguka chini. 238 00:10:25,100 --> 00:10:29,400 Hiyo ilikuwa nini watu wengi aliona, kama fireballs kubwa katika anga, 239 00:10:29,400 --> 00:10:34,930 na kutoeleweka kama intercepts ya warheads Scud. 240 00:10:34,930 --> 00:10:37,490 >> Pamoja na kwamba, katika anga la usiku, Patriots alionekana kuwa 241 00:10:37,490 --> 00:10:41,570 mafanikio kuharibiwa Scuds, saa Dhahran, kunaweza kuwa hakuna 242 00:10:41,570 --> 00:10:43,730 makosa kuhusu utendaji wake. 243 00:10:43,730 --> 00:10:46,370 Kuna, rada Patriot mfumo wa waliopotea track ya 244 00:10:46,370 --> 00:10:50,090 zinazoingia Scud na kamwe ilizindua kutokana 245 00:10:50,090 --> 00:10:51,340 kwa flaw programu. 246 00:10:54,030 --> 00:10:57,050 Ilikuwa Israel ambao kwanza aligundua kwamba tena 247 00:10:57,050 --> 00:11:02,000 mfumo ilikuwa juu, kubwa zaidi iliyopo wakati akawa, 248 00:11:02,000 --> 00:11:05,530 kutokana na saa iliyoingia katika mfumo wa kompyuta wa. 249 00:11:05,530 --> 00:11:09,060 Kuhusu wiki mbili kabla ya janga katika Dhahran, 250 00:11:09,060 --> 00:11:11,730 Israel taarifa kwa Wizara ya Ulinzi ya kwamba 251 00:11:11,730 --> 00:11:13,250 mfumo alikuwa kupoteza muda. 252 00:11:13,250 --> 00:11:15,610 Baada ya masaa nane ya mbio, waligundua kuwa, 253 00:11:15,610 --> 00:11:18,330 mfumo alikuwa kuwa noticeably chini sahihi. 254 00:11:18,330 --> 00:11:20,910 Wizara ya Ulinzi alijibu kwa kuwaambia yote ya 255 00:11:20,910 --> 00:11:23,710 Betri Patriot na si kuondoka mifumo 256 00:11:23,710 --> 00:11:25,450 kwa muda mrefu. 257 00:11:25,450 --> 00:11:28,010 Wao kamwe alisema nini muda mrefu alikuwa - masaa 8, 10 258 00:11:28,010 --> 00:11:29,690 masaa, masaa 1,000. 259 00:11:29,690 --> 00:11:31,940 Hakuna aliyejua. 260 00:11:31,940 --> 00:11:35,020 >> Betri Patriot stationed katika kambi ya saa Dhahran 261 00:11:35,020 --> 00:11:39,030 na ndani yake saa kiujanja alikuwa juu ya zaidi ya masaa 100 juu ya 262 00:11:39,030 --> 00:11:42,240 usiku wa Februari 25. 263 00:11:42,240 --> 00:11:46,580 Ni msisimko huo kwa usahihi ya juu ya kumi ya pili. 264 00:11:46,580 --> 00:11:48,830 Sasa ya kumi ya pili ni idadi ya kuvutia kwa sababu 265 00:11:48,830 --> 00:11:52,660 haiwezi kuwa walionyesha katika binary, hasa, ambayo ina maana 266 00:11:52,660 --> 00:11:54,940 haiwezi kuwa walionyesha hasa katika yoyote 267 00:11:54,940 --> 00:11:57,330 kisasa ya digital kompyuta. 268 00:11:57,330 --> 00:11:59,130 Ni vigumu kuamini. 269 00:11:59,130 --> 00:12:01,720 Lakini kutumia hii kama mfano. 270 00:12:01,720 --> 00:12:04,090 >> Hebu kuchukua namba moja ya tatu. 271 00:12:04,090 --> 00:12:07,950 Tatu Mtu hawezi kuwa walionyesha katika decimal, hasa. 272 00:12:07,950 --> 00:12:12,710 Moja ya tatu ni 0.333 kinachoendelea kwa infinity. 273 00:12:12,710 --> 00:12:17,050 Hakuna njia ya kufanya hivyo kwa usahihi kabisa katika decimal. 274 00:12:17,050 --> 00:12:19,340 Hiyo hasa aina moja ya tatizo kwamba kilichotokea katika 275 00:12:19,340 --> 00:12:20,190 Patriot. 276 00:12:20,190 --> 00:12:24,680 tena mfumo mbio, mbaya kosa wakati akawa. 277 00:12:24,680 --> 00:12:28,640 Baada ya masaa 100 ya operesheni, hitilafu katika wakati ilikuwa tu 278 00:12:28,640 --> 00:12:29,870 theluthi moja ya pili. 279 00:12:29,870 --> 00:12:34,790 Lakini katika suala la kulenga kombora kusafiri saa Mach 5, 280 00:12:34,790 --> 00:12:39,140 ni matokeo ya makosa ya kufuatilia zaidi ya mita 600. 281 00:12:39,140 --> 00:12:42,510 Itakuwa kosa mbaya kwa askari katika Dhahran. 282 00:12:42,510 --> 00:12:48,680 >> Ni nini kilichotokea uzinduzi Scud alikuwa wanaona kwa onyo mapema 283 00:12:48,680 --> 00:12:52,440 satelaiti na walijua ya kwamba Scud alikuwa anakuja katika zao 284 00:12:52,440 --> 00:12:53,350 ujumla mwelekeo. 285 00:12:53,350 --> 00:12:55,470 Hawakujua ambapo alikuwa anakuja. 286 00:12:55,470 --> 00:12:58,210 Ilikuwa sasa hadi sehemu ya rada ya Patriot 287 00:12:58,210 --> 00:13:01,920 mfumo, na kutetea Dhahran, na Machapisho na kuweka wimbo wa 288 00:13:01,920 --> 00:13:03,700 zinazoingia adui kombora. 289 00:13:03,700 --> 00:13:05,390 rada ilikuwa smart sana. 290 00:13:05,390 --> 00:13:07,570 Wewe ingekuwa kweli kufuatilia nafasi ya Scud na kisha 291 00:13:07,570 --> 00:13:10,340 kutabiri ambapo pengine itakuwa wakati ujao 292 00:13:10,340 --> 00:13:12,040 rada alimtuma Pulse nje. 293 00:13:12,040 --> 00:13:13,730 Hiyo ilikuwa inaitwa lango mbalimbali. 294 00:13:13,730 --> 00:13:18,820 Basi, mara moja anaamua Patriot muda wa kutosha kupita kwenda 295 00:13:18,820 --> 00:13:22,600 nyuma na kuangalia mahali ijayo kwa ajili ya hii wanaona 296 00:13:22,600 --> 00:13:24,190 kitu, unaendelea nyuma. 297 00:13:24,190 --> 00:13:27,940 Hivyo linapokuja akarudi mahali makosa, basi anaona hakuna 298 00:13:27,940 --> 00:13:31,000 kupinga, na anaamua kwamba kulikuwa hakuna kitu. 299 00:13:31,000 --> 00:13:34,370 Ilikuwa kugundua uongo na matone kufuatilia. 300 00:13:34,370 --> 00:13:37,630 >> Scud zinazoingia kutoweka kutoka screen rada. 301 00:13:37,630 --> 00:13:41,300 Na sekunde baadaye, slammed katika ngome ya jeshi. Scud 302 00:13:41,300 --> 00:13:44,730 kuuawa 28 na alikuwa mmoja wa mwisho fired wakati 303 00:13:44,730 --> 00:13:46,450 kwanza Vita ya Ghuba. 304 00:13:46,450 --> 00:13:50,570 Kusikitisha, programu updated aliwasili katika Dhahran 305 00:13:50,570 --> 00:13:52,060 siku iliyofuata. 306 00:13:52,060 --> 00:13:56,210 Na flaw programu amekuwa fasta, kufunga sura moja katika 307 00:13:56,210 --> 00:13:58,370 historia ya matatizo ya kombora Patriot. 308 00:14:01,790 --> 00:14:04,990 Wazalendo ni kweli kifupi kwa Tracking "phased Array 309 00:14:04,990 --> 00:14:08,516 Intercept ya Lugha. " 310 00:14:08,516 --> 00:14:13,390 >> Haki ya wote, hivyo matokeo mengi zaidi ya huzuni kabisa 311 00:14:13,390 --> 00:14:14,430 kuelewa dunia hii. 312 00:14:14,430 --> 00:14:18,180 Na takeaway, kwa kweli, kutoka katika filamu ni kwamba ufumbuzi 313 00:14:18,180 --> 00:14:20,790 kulikuwa reboot kombora yako mfumo wa ulinzi 314 00:14:20,790 --> 00:14:21,770 kila mara moja kwa wakati. 315 00:14:21,770 --> 00:14:24,280 Na hivyo tena, moja ya malengo ya kozi hii, hakika 316 00:14:24,280 --> 00:14:26,900 juu ya wadogo mnyenyekevu zaidi kuliko maombi hayo, ni kwa 317 00:14:26,900 --> 00:14:30,710 kweli wazi kila mtu macho hasa jinsi ya kwenda juu 318 00:14:30,710 --> 00:14:34,380 kufanya mashine kufanya nini unataka kufanya na jinsi ya kwenda 319 00:14:34,380 --> 00:14:37,180 juu ya kufanya kwamba usahihi, wakati njiani kufanya hivyo 320 00:14:37,180 --> 00:14:38,810 vizuri, elegantly, na kadhalika. 321 00:14:38,810 --> 00:14:41,680 Na hivyo leo, hebu tuzame ndani ya kidogo zaidi ya hii, lakini 322 00:14:41,680 --> 00:14:44,210 hivyo kwamba sisi si kwenda kwa haraka sana, hasa kwa wale chini 323 00:14:44,210 --> 00:14:46,590 starehe, lakini pia ili tuweze kuhifadhi na maslahi ya 324 00:14:46,590 --> 00:14:49,390 wale vizuri zaidi, hebu haraka tu kuanza na kidogo 325 00:14:49,390 --> 00:14:50,970 ya recap ya baadhi ya mawazo haya. 326 00:14:50,970 --> 00:14:53,710 Na tena, kuuliza mbali, wote katika mtu au online, kama una 327 00:14:53,710 --> 00:14:56,320 maswali ili tuweze kuweka kila mtu juu ya ukurasa huo. 328 00:14:56,320 --> 00:14:58,820 >> Hivyo Appliance CS50, haraka hatua nyuma, ni 329 00:14:58,820 --> 00:15:02,360 nini, kwa maneno yako mwenyewe? 330 00:15:02,360 --> 00:15:06,454 Ni sawa kama una sijui nini maneno hayo inaweza kuwa bado. 331 00:15:06,454 --> 00:15:07,830 [Inaudible] 332 00:15:07,830 --> 00:15:10,950 Sawa, hivyo interface zima kwa - 333 00:15:10,950 --> 00:15:11,900 kwamba sisi wote kushiriki. 334 00:15:11,900 --> 00:15:12,470 Kabisa. 335 00:15:12,470 --> 00:15:14,840 Hivyo tunaweza, kwa mfano, kukuambia kwenda baadhi 336 00:15:14,840 --> 00:15:16,910 tovuti, kupakua programu hii kwa ajili ya Mac OS. 337 00:15:16,910 --> 00:15:19,140 Shusha hii programu ya Windows, configure katika 338 00:15:19,140 --> 00:15:20,100 njia hii na kwamba. 339 00:15:20,100 --> 00:15:22,370 Lakini ukweli ni basi sisi kukimbia katika kiufundi wasiohesabika 340 00:15:22,370 --> 00:15:23,200 kuunga mkono masuala. 341 00:15:23,200 --> 00:15:26,630 Na pia siku hizi, mengi ya nini kinafanyika server upande, 342 00:15:26,630 --> 00:15:28,490 katika ulimwengu wa kompyuta, hasa linapokuja 343 00:15:28,490 --> 00:15:31,460 maendeleo ya mtandao na mtandao maombi ya msingi, ni kweli 344 00:15:31,460 --> 00:15:35,110 mara nyingi kabisa kufanyika kwenye kompyuta Unix au Linux, kinyume na 345 00:15:35,110 --> 00:15:36,800 Macs au Windows persondatorer. 346 00:15:36,800 --> 00:15:39,240 >> Hivyo kati ya upsides, basi, ya kutumia kitu kinachoitwa 347 00:15:39,240 --> 00:15:41,500 CS50 Appliance ni wote tutaweza kuwa na mazingira sawa. 348 00:15:41,500 --> 00:15:43,670 Hivyo kila mtu ni katika ukurasa huo huo bila kujali vifaa wewe 349 00:15:43,670 --> 00:15:46,650 alikuja na chuo lakini pia itakuwa dabbling katika hasa 350 00:15:46,650 --> 00:15:48,230 mazingira sawa kwamba wewe utakuwa kutumia kuelekea 351 00:15:48,230 --> 00:15:51,080 mwisho wa muhula na pia kwa ajili ya maendeleo ya mtandao, kama vile katika 352 00:15:51,080 --> 00:15:53,580 baadaye kwa ajili ya maombi ya ulimwengu halisi yake. 353 00:15:53,580 --> 00:15:56,350 Hivyo zaidi concretely, Appliance CS50 ni kipande bure ya 354 00:15:56,350 --> 00:15:59,400 programu ambayo inaruhusu wewe kukimbia mwingine mfumo wa uendeshaji, 355 00:15:59,400 --> 00:16:02,670 Linux, katika kesi hii, kwenye kompyuta yako mwenyewe, katika dirisha. 356 00:16:02,670 --> 00:16:04,750 Sasa huwezi download appliance. 357 00:16:04,750 --> 00:16:08,170 Unahitaji mpango ambayo kucheza au kukimbia appliance. 358 00:16:08,170 --> 00:16:11,220 Na kipande ile ya programu ni ujumla inayojulikana kama 359 00:16:11,220 --> 00:16:11,520 hypervisor. 360 00:16:11,520 --> 00:16:14,050 Hypervisors kuja katika mfumo wa bidhaa kama VMware, 361 00:16:14,050 --> 00:16:15,820 Virtual Box, uwiano. 362 00:16:15,820 --> 00:16:18,390 Kila aina ya makampuni kufanya programu, za bure na 363 00:16:18,390 --> 00:16:19,310 kibiashara, sawa. 364 00:16:19,310 --> 00:16:21,480 Nini utaona katika Tatizo Set 1 ni maelekezo ya jinsi ya 365 00:16:21,480 --> 00:16:23,440 kupata programu huru na ambayo kwa 366 00:16:23,440 --> 00:16:25,000 kukimbia Appliance CS50. 367 00:16:25,000 --> 00:16:28,060 Na mara tu kufanya, itabidi, katika dirisha juu ya Mac au PC yako, 368 00:16:28,060 --> 00:16:30,710 mazingira desktop kwamba inaonekana kabisa kama hii, ambapo 369 00:16:30,710 --> 00:16:33,100 ina Start menu-kama kitu katika 370 00:16:33,100 --> 00:16:34,510 chini kushoto kona. 371 00:16:34,510 --> 00:16:38,030 Ina folder Home, au directory Nyumbani, katika upande wa juu kushoto 372 00:16:38,030 --> 00:16:40,280 huko, takataka unaweza, na kadhalika. 373 00:16:40,280 --> 00:16:43,450 Hivyo tutaweza tease mbali maelezo muhimu kama sisi kwenda. 374 00:16:43,450 --> 00:16:46,430 >> Lakini sasa hebu kuanza kupiga mbizi katika C. 375 00:16:46,430 --> 00:16:49,200 Hivyo C ni lugha ya programu hii, sawa katika roho kwa 376 00:16:49,200 --> 00:16:52,390 Scratch, lakini mbali kidogo graphical, lakini hazijaingizwa mbali 377 00:16:52,390 --> 00:16:54,730 nguvu zaidi mara moja kupata savvy na hayo. 378 00:16:54,730 --> 00:16:58,970 Hivyo katika C, sisi kuandika mipango kwa kuandika chanzo code, ambayo ni 379 00:16:58,970 --> 00:17:01,640 hii syntax Kiingereza-kama, sawa na soksi 380 00:17:01,640 --> 00:17:05,609 maandamano ya kwamba sisi alivyofanya mara ya mwisho kwamba utapata 381 00:17:05,609 --> 00:17:07,910 kueleza mwenyewe uungwana just, ikiwa 382 00:17:07,910 --> 00:17:09,760 arcanely, kwa kompyuta. 383 00:17:09,760 --> 00:17:11,960 >> Hivyo ni aina gani ya bidhaa programu gani kwa kweli wanahitaji 384 00:17:11,960 --> 00:17:15,520 kuandika katika lugha ya programu kama C, kwa kuzingatia wetu 385 00:17:15,520 --> 00:17:17,492 mazungumzo juu ya Jumatatu? 386 00:17:17,492 --> 00:17:19,650 [Inaudible] 387 00:17:19,650 --> 00:17:21,079 OK, wewe tu haja ya mhariri wa maandishi. 388 00:17:21,079 --> 00:17:22,890 Huna haja yoyote ya programu maalum 389 00:17:22,890 --> 00:17:24,460 per se na kuandika mipango. 390 00:17:24,460 --> 00:17:27,220 Wewe tu haja ya mhariri Nakala kama Notepad, juu ya Windows, 391 00:17:27,220 --> 00:17:30,450 TextEdit ya Mac, au kitu kinachoitwa gedit, katika dunia ya 392 00:17:30,450 --> 00:17:32,020 Linux, ambayo tutaweza kutumia hapa. 393 00:17:32,020 --> 00:17:33,750 Na hiyo ni yake, na kuandika mipango. 394 00:17:33,750 --> 00:17:35,480 >> Lakini maandishi tu nusu ya equation. 395 00:17:35,480 --> 00:17:36,630 Wewe basi haja ya kukimbia kwao. 396 00:17:36,630 --> 00:17:38,320 Lakini ili kuendesha programu - 397 00:17:38,320 --> 00:17:39,600 huwezi kuendesha chanzo code. 398 00:17:39,600 --> 00:17:41,500 Wewe badala yake kuwa kufanya nini ni ya kwanza? 399 00:17:41,500 --> 00:17:41,900 Yeah. 400 00:17:41,900 --> 00:17:43,200 DAVID J. Malan: Unahitaji 401 00:17:43,200 --> 00:17:44,130 kukusanya yake. 402 00:17:44,130 --> 00:17:49,010 Na, mtu mwingine, kuandaa chanzo code ina maana - 403 00:17:49,010 --> 00:17:50,260 [Inaudible] 404 00:17:52,300 --> 00:17:52,700 DAVID J. Malan: Hasa. 405 00:17:52,700 --> 00:17:54,430 Kutafsiri kwa zeros na ndio. 406 00:17:54,430 --> 00:17:57,150 Kwa sababu sisi wote, siku hizi, na kompyuta ambayo CPUs, 407 00:17:57,150 --> 00:18:00,350 karibu wote ambao ni yaliyotolewa na kampuni iitwayo Intel, na 408 00:18:00,350 --> 00:18:03,320 Intel Ndani, ina maana kuna hii ndani ya ubongo wa yako 409 00:18:03,320 --> 00:18:04,990 kompyuta, inayojulikana kama CPU. 410 00:18:04,990 --> 00:18:07,570 Na moja ya mambo kwamba ubongo ni kwamba hana, anajua 411 00:18:07,570 --> 00:18:10,390 jinsi ya kuelewa mifumo ya zeros na ndio. 412 00:18:10,390 --> 00:18:13,240 Ni anajua mfano wa bits inawakilisha Aidha, nini 413 00:18:13,240 --> 00:18:15,500 mfano inawakilisha vipunguzi, nini mfano wa 414 00:18:15,500 --> 00:18:18,890 bits kuwakilisha uchapishaji, na kujenga sauti ya kusikika. 415 00:18:18,890 --> 00:18:22,450 >> Hivyo katika muda mfupi, CPU, pamoja na mfumo wa uendeshaji, 416 00:18:22,450 --> 00:18:25,230 ambayo ni kipande cha programu kwamba anaendesha juu ya CPU, 417 00:18:25,230 --> 00:18:26,050 hivyo kusema. 418 00:18:26,050 --> 00:18:29,850 Pamoja, wale vipande viwili kujua jinsi ya kuendesha mipango 419 00:18:29,850 --> 00:18:31,070 sisi wanadamu kuandika. 420 00:18:31,070 --> 00:18:34,040 >> Hivyo kama mimi kwenda katika appliance CS50 hapa, mimi haja ya kufungua 421 00:18:34,040 --> 00:18:35,660 up mhariri asilia na mimi wanaweza kupata hii 422 00:18:35,660 --> 00:18:36,560 katika michache ya njia. 423 00:18:36,560 --> 00:18:39,060 Naweza aidha kwenda Menu, Programming, 424 00:18:39,060 --> 00:18:40,230 na kisha naweza kuchagua - 425 00:18:40,230 --> 00:18:40,810 nope, si kwamba menu. 426 00:18:40,810 --> 00:18:43,860 Naweza kwenda Accessories / gedit hapa kwa kufungua 427 00:18:43,860 --> 00:18:45,090 Nakala yangu kidogo mhariri. 428 00:18:45,090 --> 00:18:48,030 Au kwa urahisi zaidi, naweza bofya ikoni hii kidogo katika chini 429 00:18:48,030 --> 00:18:48,970 mkono wa kushoto kona. 430 00:18:48,970 --> 00:18:50,430 Na sasa mimi kupata hii mazingira hapa. 431 00:18:50,430 --> 00:18:52,590 Ni pretty kukumbusha ya mhariri rahisi Nakala, pamoja na haki 432 00:18:52,590 --> 00:18:53,820 moja au mbili tofauti. 433 00:18:53,820 --> 00:18:56,420 Katika ya juu, ambapo mshale ni blinking sasa, hii ni mahali ambapo 434 00:18:56,420 --> 00:18:57,900 Naweza kuanza kuandika code yangu. 435 00:18:57,900 --> 00:19:00,415 Katika ya chini ni kitu hii inaitwa dirisha terminal. 436 00:19:00,415 --> 00:19:03,400 Na ni aina gani ya mambo yanaweza mimi kwa hii 437 00:19:03,400 --> 00:19:04,960 kinachojulikana terminal dirisha? 438 00:19:04,960 --> 00:19:06,680 [Inaudible] 439 00:19:06,680 --> 00:19:07,890 >> Sawa, hivyo mimi itabidi kukimbia amri. 440 00:19:07,890 --> 00:19:10,300 Na baadhi ya amri sisi mbio Jumatatu walikuwa kidogo 441 00:19:10,300 --> 00:19:15,070 cryptic mara ya kwanza, lakini ls kwa orodha, cd kwa saraka ya mabadiliko, 442 00:19:15,070 --> 00:19:16,540 rm, kwa kuondoa. 443 00:19:16,540 --> 00:19:19,680 Hivyo ni aina ya njia ya zamani-shule ya navigering yako 444 00:19:19,680 --> 00:19:22,310 kompyuta, kwa kutumia tu keyboard yako na amri textual, 445 00:19:22,310 --> 00:19:24,130 na si, kwa ujumla, kwa kutumia mouse. 446 00:19:24,130 --> 00:19:25,960 Lakini tutaweza kuona, kabla ya muda mrefu, hii kwa kweli inatupa 447 00:19:25,960 --> 00:19:28,520 kidogo nguvu zaidi na zaidi kidogo usahihi na ambayo kwa 448 00:19:28,520 --> 00:19:29,600 kueleza sisi wenyewe. 449 00:19:29,600 --> 00:19:31,330 Na kisha juu hapa kushoto, sisi ni kwenda tu kuona, 450 00:19:31,330 --> 00:19:34,360 kama sisi kuanza kuandika programu, muhtasari kidogo ya 451 00:19:34,360 --> 00:19:36,350 mpango kwamba tumekuwa yaliyoandikwa juu kushoto. 452 00:19:36,350 --> 00:19:38,360 Lakini tutaweza kuona kwamba tena kabla ya muda mrefu. 453 00:19:38,360 --> 00:19:40,050 >> Basi hebu kufanya kitu haki rahisi hapa. 454 00:19:40,050 --> 00:19:43,440 Hebu kwanza kwenda mbele na kwenda faili, Ila, na mimi nina haki 455 00:19:43,440 --> 00:19:45,970 kwenda bonyeza jharvard hapa, juu ya kushoto, na 456 00:19:45,970 --> 00:19:48,930 jharvard ni, tena, jina kwa ajili ya nyumba folder yangu, 457 00:19:48,930 --> 00:19:52,110 binafsi files, mimi, sasa kuwa Yohana Harvard, kama yote ya wewe 458 00:19:52,110 --> 00:19:54,230 hivi karibuni kuwa Yohana Harvard katika mazingira haya. 459 00:19:54,230 --> 00:19:57,360 Anacho saraka hii Home, My Documents na kadhalika, 460 00:19:57,360 --> 00:19:58,900 kwamba mimi nataka kuokoa, sasa, faili hii in 461 00:19:58,900 --> 00:20:01,520 Hivyo nina kwenda kwa simu yake hello.c. Kisha mimi nina kwenda 462 00:20:01,520 --> 00:20:05,770 mbele na bonyeza Ila, na sasa nini mimi hapa ni tab 463 00:20:05,770 --> 00:20:09,440 kuitwa hello.c, hivyo kiasi kama aina nyingine ya mhariri. 464 00:20:09,440 --> 00:20:11,760 >> Hivyo sasa napenda kwenda mbele na kuanza kuandika mpango. 465 00:20:11,760 --> 00:20:14,440 int kuu (utupu). 466 00:20:14,440 --> 00:20:18,150 Na kisha mimi tu alifanya wakati wa mwisho, printf, kwa ajili ya magazeti formatted, 467 00:20:18,150 --> 00:20:22,120 ("Hello, ulimwengu!" 468 00:20:22,120 --> 00:20:24,500 );. 469 00:20:24,500 --> 00:20:25,630 Karibu kukamilisha. 470 00:20:25,630 --> 00:20:27,130 Lakini mimi kukosa michache ya maelezo. 471 00:20:27,130 --> 00:20:30,210 Ni nini kinachokosekana ya mpango huu kwamba mimi kwa kweli wanahitaji kwa 472 00:20:30,210 --> 00:20:31,890 kwa kweli kukusanya? 473 00:20:31,890 --> 00:20:32,130 Yeah. 474 00:20:32,130 --> 00:20:33,980 [Inaudible]? 475 00:20:33,980 --> 00:20:35,770 >> DAVID J. Malan: Yeah, hivyo mimi haja ya ni pamoja na kiwango 476 00:20:35,770 --> 00:20:36,700 I / O maktaba. 477 00:20:36,700 --> 00:20:39,470 Hivyo hii mahitaji ya kwenda juu kuu, hivyo mimi nina kwenda tu 478 00:20:39,470 --> 00:20:40,790 kufanya baadhi ya chumba kwa ajili yake huko. 479 00:20:40,790 --> 00:20:44,420 Na mimi naenda kufanya # pamoja . 480 00:20:44,420 --> 00:20:46,570 Na taarifa ya mabano angled huko. 481 00:20:46,570 --> 00:20:49,410 Na kama kando, gedit ni mtumiaji kidogo kirafiki, ikiwa 482 00:20:49,410 --> 00:20:52,420 wakati mwingine utata kidogo, kwa kuwa inajaribu kusaidia yako 483 00:20:52,420 --> 00:20:54,770 macho ilani nini yanaendana na nini. 484 00:20:54,770 --> 00:20:57,760 Hivyo ukweli kwamba mshale wangu ni haki ya karibu na hii angled 485 00:20:57,760 --> 00:21:00,600 bracket, taarifa jinsi ni mwangaza angled nyingine 486 00:21:00,600 --> 00:21:01,920 bracket plus hii moja. 487 00:21:01,920 --> 00:21:03,770 Na kwamba tu kuteka mawazo yangu na ukweli kwamba mimi 488 00:21:03,770 --> 00:21:04,460 vina ulinganifu. 489 00:21:04,460 --> 00:21:07,010 Na ulinganifu katika programu ujumla ni jambo jema. 490 00:21:07,010 --> 00:21:10,270 Vile vile, kama mimi hoja yangu mshale hadi mwisho, taarifa jinsi 491 00:21:10,270 --> 00:21:13,630 braces curly line up kuonyesha kwamba, ndiyo, nina moja wazi 492 00:21:13,630 --> 00:21:15,160 na moja imefungwa, hivyo kusema. 493 00:21:15,160 --> 00:21:16,640 >> Yote ya haki, na mimi siwezi kufanya kitu moja nyingine. 494 00:21:16,640 --> 00:21:20,090 Ni muhimu si madhubuti, lakini mazoezi mazuri, kusema 495 00:21:20,090 --> 00:21:21,250 kurudi 0. 496 00:21:21,250 --> 00:21:24,140 Na kurudi 0 anafanya nini kwa sisi hapa? 497 00:21:24,140 --> 00:21:25,584 Au kunaashiria nini? 498 00:21:25,584 --> 00:21:27,480 [Inaudible] 499 00:21:27,480 --> 00:21:28,300 DAVID J. Malan: Lakini ni kitu kibaya. 500 00:21:28,300 --> 00:21:30,280 Na kusema ukweli ni vigumu kwa kiasi cha kwenda vibaya katika 501 00:21:30,280 --> 00:21:31,250 mpango huu mfupi. 502 00:21:31,250 --> 00:21:33,930 Hivyo nina tu kuwa super wazi kwamba yote ni sawa. 503 00:21:33,930 --> 00:21:36,740 Mimi, binadamu, wakati mimi kukimbia katika mpango huu, mapenzi pengine kamwe 504 00:21:36,740 --> 00:21:38,150 kuona kwamba 0. 505 00:21:38,150 --> 00:21:41,070 Kwa ujumla, nambari hizi kuwa ni kuwa alirejea kutoka kuu 506 00:21:41,070 --> 00:21:43,540 tu cha nyuma vichwa vyao kwa binadamu wakati 507 00:21:43,540 --> 00:21:44,360 kitu fulani kitaenda vibaya. 508 00:21:44,360 --> 00:21:46,640 Na kupata pop kidogo juu kosa akisema mfumo, moja, 509 00:21:46,640 --> 00:21:48,760 mbili, tatu, au chochote idadi ilikuwa kwamba 510 00:21:48,760 --> 00:21:50,100 alikuwa kweli akarudi. 511 00:21:50,100 --> 00:21:52,870 Hivyo kitu kingine chochote kibaya na hili? 512 00:21:52,870 --> 00:21:55,300 [Inaudible] 513 00:21:55,300 --> 00:21:58,100 >> DAVID J. Malan: Hivyo hii si kiasi kosa kazi 514 00:21:58,100 --> 00:21:59,240 lakini moja aesthetic. 515 00:21:59,240 --> 00:22:02,340 Mimi lazima pengine kuweka katika tabia newline huko 516 00:22:02,340 --> 00:22:05,240 mwisho wa kamba hii ili kwamba sisi kweli hoja cursor 517 00:22:05,240 --> 00:22:08,340 mstari unaofuata, na mpango tu inaonekana kidogo prettier. 518 00:22:08,340 --> 00:22:10,340 >> Hivyo sasa napenda kwenda chini kwa terminal dirisha yangu 519 00:22:10,340 --> 00:22:11,490 na zoom nyuma in 520 00:22:11,490 --> 00:22:13,390 Na jambo hili hapa, ni wito wa haraka. 521 00:22:13,390 --> 00:22:16,760 Ni tu kuwakumbusha yangu mimi ni nani, jharvard @ appliance, ambapo 522 00:22:16,760 --> 00:22:18,850 appliance ni jina la kompyuta mimi nina juu. 523 00:22:18,850 --> 00:22:22,380 Katika mabano ni hii tilde, alama squiggle, ambayo 524 00:22:22,380 --> 00:22:24,160 inawakilisha nini? 525 00:22:24,160 --> 00:22:25,590 Watazamaji: Nyumbani directory. 526 00:22:25,590 --> 00:22:26,350 DAVID J. Malan: Nyumbani directory. 527 00:22:26,350 --> 00:22:29,350 Basi hiyo ni tu nukuu shorthand kwa kusema wewe ni katika 528 00:22:29,350 --> 00:22:32,780 folder yako binafsi ambapo wote wa files yako kwenda kwa default. 529 00:22:32,780 --> 00:22:36,080 Hivyo sasa, katika hapa, mimi unaweza aina ls kwa orodha. 530 00:22:36,080 --> 00:22:40,020 Na kitu tu naona hapa wakati huu ni hello.c. 531 00:22:40,020 --> 00:22:41,770 Na kwamba ni nzuri kwa sababu mimi tu aliandika hii. 532 00:22:41,770 --> 00:22:44,380 >> Hivyo basi mimi kwenda mbele na kufanya kufanya hello. 533 00:22:44,380 --> 00:22:46,830 Na taarifa mimi nina kuandika kufanya hello.c. 534 00:22:46,830 --> 00:22:50,300 Badala yake, mimi nina tu kuandika jina ya msingi ya SVG, hello. 535 00:22:50,300 --> 00:22:53,690 Na kufanya, kama tuliona juu ya Jumatatu, itakuwa tu ya kudai kuwa nataka 536 00:22:53,690 --> 00:22:54,920 C. Faili. 537 00:22:54,920 --> 00:22:56,820 Hivyo sasa nimekuwa typed kufanya hello. 538 00:22:56,820 --> 00:22:59,280 Sasa naona hii amri uungwana muda mrefu na itaendelea 539 00:22:59,280 --> 00:23:00,480 kuona hii tena na tena. 540 00:23:00,480 --> 00:23:03,620 Lakini kwa kuwa wazi, Clang, neno kwamba tu alionekana, 541 00:23:03,620 --> 00:23:05,340 hiyo ni mkusanyaji halisi. 542 00:23:05,340 --> 00:23:08,200 Kufanya ni tu shirika kujenga. 543 00:23:08,200 --> 00:23:11,900 Ni tu zaidi user friendly mpango kwamba anaokoa mimi, katika 544 00:23:11,900 --> 00:23:15,310 muda mrefu kukimbia, kutoka kuwa na aina nje incredibly tedious muda mrefu 545 00:23:15,310 --> 00:23:17,020 amri kama hiyo moja. 546 00:23:17,020 --> 00:23:18,950 Hivyo unaweza kukimbia Clang manually. 547 00:23:18,950 --> 00:23:20,530 Unaweza aina yote ya kwamba manually. 548 00:23:20,530 --> 00:23:21,580 Tu anapata tedious sana. 549 00:23:21,580 --> 00:23:24,720 Na hivyo kufanya ni tu mpango kwamba simplifies maisha yetu na 550 00:23:24,720 --> 00:23:27,120 anaendesha amri ngumu zaidi kwa ajili yetu. 551 00:23:27,120 --> 00:23:29,410 >> Haki ya wote, hivyo sasa nini faili lazima nina 552 00:23:29,410 --> 00:23:31,540 katika saraka yangu ya sasa? 553 00:23:31,540 --> 00:23:36,310 Si tu hello.c, lakini pia hello. 554 00:23:36,310 --> 00:23:39,710 Hivyo kama nataka kukimbia hello, wanakumbuka kwamba nasema dot slash, 555 00:23:39,710 --> 00:23:42,220 ambapo dot njia kwenda katika folder sasa, popote 556 00:23:42,220 --> 00:23:46,060 ni, na kisha kukimbia programu inayoitwa hello, na kwa kweli, sasa, 557 00:23:46,060 --> 00:23:48,080 Nina dunia hello. 558 00:23:48,080 --> 00:23:51,640 Haki zote, maswali yoyote juu ya workflow au syntax ya 559 00:23:51,640 --> 00:23:52,890 nini sisi tu alivyofanya? 560 00:23:55,380 --> 00:23:57,040 >> Haki zote, hivyo hebu kuchukua mambo juu notch tena. 561 00:23:57,040 --> 00:24:00,430 Hivyo hii ilikuwa aghali kwa kuandika tu mpango kwamba tu 562 00:24:00,430 --> 00:24:01,790 milele anasema hello, ulimwengu. 563 00:24:01,790 --> 00:24:03,920 Hivyo sisi iliyopita yake, juu ya Jumatatu, kusema, hello, Daudi. 564 00:24:03,920 --> 00:24:06,560 Ni kidogo zaidi ya binafsi, lakini tu kama ngumu kama coded 565 00:24:06,560 --> 00:24:07,410 kwanza version. 566 00:24:07,410 --> 00:24:08,780 Hivyo si yote ya kulazimisha. 567 00:24:08,780 --> 00:24:13,120 Lakini kuna lipo, katika C, kazi ya shaka badala ya 568 00:24:13,120 --> 00:24:15,700 magazeti, kazi ambayo basi kupata mtumiaji pembejeo. 569 00:24:15,700 --> 00:24:17,990 Na njia ya sisi alifanya hivyo, siku nyingine, ilikuwa kama ifuatavyo. 570 00:24:17,990 --> 00:24:21,440 Kabla ya mimi kwa kweli magazeti nje kitu, mimi kwanza got 571 00:24:21,440 --> 00:24:22,410 kitu kutoka kwa mtumiaji. 572 00:24:22,410 --> 00:24:23,370 Hivyo basi mimi kufanya hii tena. 573 00:24:23,370 --> 00:24:26,580 >> Kamba s, ambapo s ni jina tu kiholela, hapa, kwa 574 00:24:26,580 --> 00:24:30,600 kamba, sawa GetString. 575 00:24:30,600 --> 00:24:32,070 Hivyo kile GetString? 576 00:24:32,070 --> 00:24:34,630 Ni wazi anapata kamba, msingi juu ya jina lake. 577 00:24:34,630 --> 00:24:37,560 Lakini ni nini, zaidi kitaalam? 578 00:24:37,560 --> 00:24:38,440 Ni kazi. 579 00:24:38,440 --> 00:24:41,790 Hivyo ni kazi ambayo haina kuja na C per se. 580 00:24:41,790 --> 00:24:43,660 CS50 wafanyakazi aliandika hii. 581 00:24:43,660 --> 00:24:46,940 Na hivyo kwa kutumia hii, huwezi tu ni pamoja na stdio.h, 582 00:24:46,940 --> 00:24:49,630 Unahitaji pia ni pamoja na nini? 583 00:24:49,630 --> 00:24:50,060 Yeah. 584 00:24:50,060 --> 00:24:54,210 Hivyo cs50.h, ambayo ni tu faili sisi aliandika baadhi ya miaka iliyopita. 585 00:24:54,210 --> 00:24:57,130 Sisi imewekwa juu ya appliance kwa wewe pamoja 586 00:24:57,130 --> 00:24:58,490 wote wa files standard. 587 00:24:58,490 --> 00:25:00,500 Na hivyo katika wiki hizi chache kwanza wa darasa, tutaweza kutumia 588 00:25:00,500 --> 00:25:02,820 hii tu kurahisisha mchakato wa kufanya msingi sana 589 00:25:02,820 --> 00:25:04,600 mambo kama kupata mtumiaji pembejeo. 590 00:25:04,600 --> 00:25:07,370 Kwa sababu kama tutaweza kuona katika wiki chache, kupata pembejeo mtumiaji katika 591 00:25:07,370 --> 00:25:10,180 Lugha kama C ni kweli kushangaza tata, 592 00:25:10,180 --> 00:25:14,360 hasa kwa sababu huna kujua mapema, kwa kawaida, jinsi 593 00:25:14,360 --> 00:25:17,030 mambo mengi mtumiaji anaenda aina in 594 00:25:17,030 --> 00:25:20,340 Na wakati huna kujua ni kiasi gani data kutarajia, huna 595 00:25:20,340 --> 00:25:22,380 kujua ni kiasi gani kumbukumbu kutenga. 596 00:25:22,380 --> 00:25:25,480 Na kama kweli wana mtumiaji adversarial ambaye ni kujaribu 597 00:25:25,480 --> 00:25:28,180 hack katika mfumo wako, ajali kompyuta yako, vizuri, 598 00:25:28,180 --> 00:25:31,600 ujumla njia ya kwanza ya mashambulizi ni, kama mimi alifanya juu ya 599 00:25:31,600 --> 00:25:34,950 Jumatatu, aina zima mrefu mlolongo wa wahusika random, 600 00:25:34,950 --> 00:25:37,020 hit Enter, na kuona nini mapumziko. 601 00:25:37,020 --> 00:25:40,800 Kwa sababu kwa ujumla, kama mapumziko mpango, anadokeza kwamba 602 00:25:40,800 --> 00:25:42,650 flaw usalama, uwezekano. 603 00:25:42,650 --> 00:25:45,250 Ni hakika anadokeza wewe, programu, baada ya kufanya 604 00:25:45,250 --> 00:25:49,050 makosa, lakini zaidi hatari, unaweza kuwa alifanya 605 00:25:49,050 --> 00:25:52,430 yanayohusiana na usalama makosa, na kwa ujumla tutaweza kuona kwamba 606 00:25:52,430 --> 00:25:54,840 hiyo ni jinsi mashine ni kuathirika kwa siku hii, wote 607 00:25:54,840 --> 00:25:56,620 katika dunia ya mtandao na programu katika 608 00:25:56,620 --> 00:25:58,070 amri line, kama hii. 609 00:25:58,070 --> 00:25:58,350 >> Wote haki. 610 00:25:58,350 --> 00:26:00,460 Hivyo string s sawa GetString. 611 00:26:00,460 --> 00:26:03,380 Hivyo zaidi concretely sasa, nini mstari 6 kufanya hapa? 612 00:26:03,380 --> 00:26:05,640 Hivyo kazi juu ya haki anapata kamba, 613 00:26:05,640 --> 00:26:06,890 inachukua jinsi hoja nyingi? 614 00:26:09,458 --> 00:26:09,900 Sawa. 615 00:26:09,900 --> 00:26:10,400 Hivyo hakuna. 616 00:26:10,400 --> 00:26:11,360 sanity kidogo kuangalia. 617 00:26:11,360 --> 00:26:15,380 hoja, tena, ni tu pembejeo ya kazi ya kubadilisha 618 00:26:15,380 --> 00:26:17,250 default yake tabia katika baadhi ya njia. 619 00:26:17,250 --> 00:26:19,540 Lakini katika kesi hii, mimi sitaki kubadilisha 620 00:26:19,540 --> 00:26:20,650 tabia ya GetString. 621 00:26:20,650 --> 00:26:22,430 Mimi nilitaka kupata kamba. 622 00:26:22,430 --> 00:26:25,190 Basi, mimi kuweka kitu katika mabano, na kisha mimi kuweka 623 00:26:25,190 --> 00:26:27,550 semicolon demarking mwisho wa mstari wa kanuni. 624 00:26:27,550 --> 00:26:29,840 Sasa, alama ya usawa haina maana sawa, per se. 625 00:26:29,840 --> 00:26:32,690 Ina maana kazi, ambayo ina maana ya kuweka chochote anapata 626 00:26:32,690 --> 00:26:36,060 outputted ndani ya haki ya chochote ni juu ya kushoto. 627 00:26:36,060 --> 00:26:39,400 >> Hivyo upande wa kushoto, sisi kusema kwamba sisi wametangaza 628 00:26:39,400 --> 00:26:41,630 kamba kuitwa s. 629 00:26:41,630 --> 00:26:44,240 Na hasa zaidi, tumekuwa zilizotengwa kumbukumbu ndani ya 630 00:26:44,240 --> 00:26:46,340 ambayo tutaweza kuweka bits kwamba inawakilisha mlolongo wa 631 00:26:46,340 --> 00:26:46,850 wahusika. 632 00:26:46,850 --> 00:26:49,400 Lakini kwa leo, tumetenga 633 00:26:49,400 --> 00:26:51,450 au alitangaza kamba. 634 00:26:51,450 --> 00:26:51,790 Wote haki. 635 00:26:51,790 --> 00:26:54,760 Hivyo sasa, mara moja mimi tumefanya hii, nataka kuziba kwa thamani ya 636 00:26:54,760 --> 00:26:56,535 s, si thamani ya Daudi. 637 00:26:56,535 --> 00:27:00,200 Hivyo hii ni makosa kwa nini? 638 00:27:03,060 --> 00:27:04,870 Hivyo hii ni haki halisi ni vigumu-coded. 639 00:27:04,870 --> 00:27:06,870 Ni kusema "hello, s," ambayo si nini nataka. 640 00:27:06,870 --> 00:27:07,790 Hivyo siwezi kufanya hivyo. 641 00:27:07,790 --> 00:27:10,330 ishara asilimia ni kishika, lakini sasa mimi haja ya 642 00:27:10,330 --> 00:27:12,520 kupita katika magazeti hoja ya pili. 643 00:27:12,520 --> 00:27:15,160 Kumbuka kwamba hoja ya utendaji ni waliojitenga na 644 00:27:15,160 --> 00:27:20,300 koma, hivyo koma ijayo hapa mimi kuweka baada ya hii ya barua. 645 00:27:20,300 --> 00:27:23,740 Na katika muktadha huu sasa, s ni kutofautiana, na printf, 646 00:27:23,740 --> 00:27:25,550 juu ya kupokea pembejeo hizo mbili - 647 00:27:25,550 --> 00:27:29,440 kamba upande wa kushoto na kutofautiana jina la juu ya haki - 648 00:27:29,440 --> 00:27:32,750 itakuwa kuziba mwisho ndani ya zamani kwa ajili yetu, na 649 00:27:32,750 --> 00:27:34,600 tu magazeti nje nzuri nzuri zenye string 650 00:27:34,600 --> 00:27:36,770 chochote ni kwamba sisi typed in 651 00:27:36,770 --> 00:27:37,560 >> Basi hebu jaribu hii. 652 00:27:37,560 --> 00:27:38,860 Kwenda mbele na zoom nje, nyuma 653 00:27:38,860 --> 00:27:40,250 terminal dirisha yangu. 654 00:27:40,250 --> 00:27:41,840 Zoom katika chini hapa. 655 00:27:41,840 --> 00:27:44,070 Retype kufanya hello. 656 00:27:44,070 --> 00:27:45,870 Clang inaonekana kuwa rerun. 657 00:27:45,870 --> 00:27:49,280 Mimi naenda aina /. Hello, Ingiza. 658 00:27:49,280 --> 00:27:52,145 Kitu inaonekana kuwa kinachotokea bado, lakini ni wakati huu wa haraka 659 00:27:52,145 --> 00:27:55,700 kwamba naweza andika kitu kama Nate, Ingieni, na sasa tuna 660 00:27:55,700 --> 00:27:56,380 Hello, Nate. 661 00:27:56,380 --> 00:27:59,600 Na siwezi kufanya hivyo tena na Rob, na kadhalika. 662 00:27:59,600 --> 00:28:03,410 Hivyo hopefully sasa mpango huu ni tabia kama mimi na nia. 663 00:28:03,410 --> 00:28:05,720 >> Sasa, si kwamba mtumiaji yote ya kirafiki. 664 00:28:05,720 --> 00:28:07,930 Nina wazo nini kuwa inatarajiwa yangu. 665 00:28:07,930 --> 00:28:09,620 Hivyo tunaweza shaka safi hii juu kidogo. 666 00:28:09,620 --> 00:28:13,270 Hebu nirejee nyuma hapa juu, na badala ya mbizi katika na 667 00:28:13,270 --> 00:28:16,480 kuuliza mtumiaji kwa kamba, basi mimi kupanga kuwaambia 668 00:28:16,480 --> 00:28:17,750 user nini mimi kutarajia. 669 00:28:17,750 --> 00:28:21,610 Hivyo printf ("Ingiza uzi:" 670 00:28:21,610 --> 00:28:24,080 ); 671 00:28:24,080 --> 00:28:25,510 Hivyo hakuna vigezo hapa. 672 00:28:25,510 --> 00:28:26,750 Ishara asilimia No. 673 00:28:26,750 --> 00:28:28,550 Rahisi tu Kiingereza maneno. 674 00:28:28,550 --> 00:28:34,030 Hebu sasa kwenda chini hapa na rerun mpango wangu. 675 00:28:34,030 --> 00:28:35,380 Lakini kitu inaonekana kuwa iliyopita. 676 00:28:35,380 --> 00:28:37,350 Kwa nini? 677 00:28:37,350 --> 00:28:38,380 Nina recompile yake. 678 00:28:38,380 --> 00:28:39,570 Hivyo kosa rahisi kutengeneza. 679 00:28:39,570 --> 00:28:41,700 Lakini una si tu kuokoa faili lakini 680 00:28:41,700 --> 00:28:43,260 recompile mpango. 681 00:28:43,260 --> 00:28:46,640 Na hivyo kama mimi kuendesha upya kufanya hello, sasa Clang anaendesha. 682 00:28:46,640 --> 00:28:51,800 Sasa siwezi kukimbia /. Hello. Na sasa naona "Ingiza uzi:". 683 00:28:51,800 --> 00:28:52,050 Sawa. 684 00:28:52,050 --> 00:28:53,440 Sasa ni zaidi kidogo user-kirafiki. 685 00:28:53,440 --> 00:28:55,850 Nate, Ingieni, hello, Nate. 686 00:28:55,850 --> 00:28:57,310 >> Naam, hebu jaribu hii tena na kuanza kufikiri 687 00:28:57,310 --> 00:28:58,080 kuhusu kona kesi. 688 00:28:58,080 --> 00:29:00,520 Hivyo kama katika Scratch, wewe ni moyo au ni kuwa 689 00:29:00,520 --> 00:29:03,180 moyo katika spec kwa aina ya kufikiri juu ya nini inaweza kwenda 690 00:29:03,180 --> 00:29:06,610 makosa kama huna wanatarajia kila kitu mtumiaji anaweza kufanya. 691 00:29:06,610 --> 00:29:08,050 Bugs, kwa hiyo, ili zichukuliwe. 692 00:29:08,050 --> 00:29:09,710 Basi ingieni string - 693 00:29:09,710 --> 00:29:11,130 nini kesi kona hapa? 694 00:29:11,130 --> 00:29:13,320 Nini hali ambayo mimi, programu, wanaweza kuwa na 695 00:29:13,320 --> 00:29:16,070 kutarajia? 696 00:29:16,070 --> 00:29:17,600 Yeah. 697 00:29:17,600 --> 00:29:17,920 Sawa. 698 00:29:17,920 --> 00:29:22,060 Basi nini kama mimi aina kwa idadi kama hii? 699 00:29:22,060 --> 00:29:22,500 Wote haki. 700 00:29:22,500 --> 00:29:24,490 Hivyo bado kazi. 701 00:29:24,490 --> 00:29:25,880 Gramatically haina mantiki. 702 00:29:25,880 --> 00:29:27,180 Lakini angalau mpango kazi. 703 00:29:27,180 --> 00:29:28,650 >> Nini kesi nyingine pembeni? 704 00:29:28,650 --> 00:29:29,610 Kitu sikuweza kutarajia. 705 00:29:29,610 --> 00:29:31,590 Yeah? 706 00:29:31,590 --> 00:29:31,940 Sawa. 707 00:29:31,940 --> 00:29:34,950 Hivyo tunaweza kufanya kitu kama idadi kweli, kweli kubwa. 708 00:29:34,950 --> 00:29:37,270 Basi hebu kufanya hivyo hapa. 709 00:29:37,270 --> 00:29:40,880 Hebu zoom nje kwa ajili ya pili, napenda kuonyesha. 710 00:29:40,880 --> 00:29:42,250 Hawawezi nakala na kuweka chini hapa. 711 00:29:42,250 --> 00:29:42,470 Wote haki. 712 00:29:42,470 --> 00:29:44,440 Hivyo siwezi nakala na kuweka katika dirisha hili terminal, hivyo tutaweza 713 00:29:44,440 --> 00:29:46,950 tu simulate yake. 714 00:29:46,950 --> 00:29:51,340 Hebu zoom nje, kwenda wrap. 715 00:29:51,340 --> 00:29:52,700 Sitakuja kufanya hivyo kwa muda mrefu sana, kwa sababu itakuwa si 716 00:29:52,700 --> 00:29:54,440 kweli kuvunja katika mpango huu. 717 00:29:54,440 --> 00:29:55,260 Lakini naweza. 718 00:29:55,260 --> 00:29:55,830 Kuingia. 719 00:29:55,830 --> 00:29:56,580 Lakini haikuwa hivyo. 720 00:29:56,580 --> 00:29:57,050 Wote haki. 721 00:29:57,050 --> 00:29:58,440 Lakini ni kweli kona kesi. 722 00:29:58,440 --> 00:30:01,610 Na sababu tu kwamba walijivuna vizuri, kwa hiyo kwa 723 00:30:01,610 --> 00:30:05,820 kuzungumza, ni kwa sababu CS50 kazi GetString ni kweli 724 00:30:05,820 --> 00:30:08,040 iliyoundwa chini ya Hood, kama tutaweza kuona katika wiki chache, 725 00:30:08,040 --> 00:30:11,570 moja kwa moja kutenga zaidi na zaidi RAM, zaidi na zaidi 726 00:30:11,570 --> 00:30:14,330 kumbukumbu kutoka mfumo wa uendeshaji, wakati anatambua, wow, 727 00:30:14,330 --> 00:30:16,670 ve kweli typed katika kitu muda mrefu kabisa. 728 00:30:16,670 --> 00:30:18,500 Sasa, hii ni kidogo ya uongo nyeupe. 729 00:30:18,500 --> 00:30:22,020 Kama sisi kweli paused kwa muda kabisa na mimi typed katika 730 00:30:22,020 --> 00:30:24,640 kitu kama wahusika bilioni 5 katika keyboard 731 00:30:24,640 --> 00:30:28,060 hapa, au kweli hit nakala-kuweka kidogo kabisa, sisi kabisa uwezekano 732 00:30:28,060 --> 00:30:29,730 inaweza kusababisha mpango kwa ajali. 733 00:30:29,730 --> 00:30:32,130 Kidogo tu vigumu kuiga kwamba pamoja na finite 734 00:30:32,130 --> 00:30:33,740 kiasi cha muda. 735 00:30:33,740 --> 00:30:37,320 >> Nini kesi nyingine kona tunaweza kujaribu? 736 00:30:37,320 --> 00:30:38,730 Yeah? 737 00:30:38,730 --> 00:30:39,020 Yeah. 738 00:30:39,020 --> 00:30:40,360 Hivyo kwa nini sisi kujibu chochote? 739 00:30:40,360 --> 00:30:43,130 Hivyo sisi kweli kuwa na kuchukua baadhi ya hatua, kwa sababu vinginevyo 740 00:30:43,130 --> 00:30:45,060 mpango kinaendelea kukaa huko blinking siku zote. 741 00:30:45,060 --> 00:30:46,860 Lakini kama mimi tu hit Enter - 742 00:30:46,860 --> 00:30:48,780 Sawa, sasa, bado inaonekana makosa. 743 00:30:48,780 --> 00:30:51,670 Je si ajali, lakini labda sasa kuna fursa ya 744 00:30:51,670 --> 00:30:54,190 kuanza kutekeleza mpango wa ukali zaidi 745 00:30:54,190 --> 00:30:55,290 kwamba kweli hundi. 746 00:30:55,290 --> 00:30:57,640 Na kama kamba, sentensi, neno kwamba mimi 747 00:30:57,640 --> 00:31:00,890 typed katika ina urefu 0, vizuri, labda mimi lazima yell katika 748 00:31:00,890 --> 00:31:03,770 mtumiaji, au kumwambia au wake kuingia string tena, ili 749 00:31:03,770 --> 00:31:06,560 sisi kweli kupata kile kinachoonekana kama tabia sahihi na si 750 00:31:06,560 --> 00:31:08,570 tu kamili kusimamia kwa upande wangu. 751 00:31:08,570 --> 00:31:11,130 >> Swali katika nyuma? 752 00:31:11,130 --> 00:31:11,970 Idadi decimal. 753 00:31:11,970 --> 00:31:13,120 Hivyo tunaweza kujaribu kuwa, pia. 754 00:31:13,120 --> 00:31:16,840 1.10000005. 755 00:31:16,840 --> 00:31:19,470 Inaonekana kama ambayo inaenda tu kazi kweli sawa. 756 00:31:19,470 --> 00:31:21,160 Na kwamba kwa kweli inatarajiwa. 757 00:31:21,160 --> 00:31:24,550 Hata ingawa sisi tupate kuwa typed kwamba idadi huko, au 758 00:31:24,550 --> 00:31:28,200 kubwa ya idadi ya awali, kutambua kwamba wakati sisi ni kuandika mtumiaji 759 00:31:28,200 --> 00:31:31,070 pembejeo na sisi ni kutumia kazi GetString, haina 760 00:31:31,070 --> 00:31:34,380 jambo kama nini mimi kuandika inaonekana kama idadi. 761 00:31:34,380 --> 00:31:36,720 Kumbuka kwamba kulingana na ASCII, kila kitu juu yako 762 00:31:36,720 --> 00:31:39,920 keyboard ina thamani namba ambayo yanaweza mapped 763 00:31:39,920 --> 00:31:41,480 tabia, char. 764 00:31:41,480 --> 00:31:44,490 Hivyo katika kesi hii, hata ingawa mimi ili aina ya namba, 765 00:31:44,490 --> 00:31:48,190 kompyuta ni kwenda kufikiria hivyo, ili kuzungumza, kama kamba - 766 00:31:48,190 --> 00:31:49,870 kitu ambacho inaonekana kama idadi, lakini ni 767 00:31:49,870 --> 00:31:51,090 si kweli idadi. 768 00:31:51,090 --> 00:31:53,450 Lakini hiyo ni kweli segue kamili, kwa sababu sasa tunaweza 769 00:31:53,450 --> 00:31:55,450 kweli ya mpito kwa mipango ya kuandika kwamba 770 00:31:55,450 --> 00:31:56,730 kutumia data aina nyingine. 771 00:31:56,730 --> 00:32:01,840 >> Hivyo badala ya kutumia chars, au tuseme, badala ya kutumia masharti, 772 00:32:01,840 --> 00:32:04,510 kutambua kwamba tuna data aina nyingine katika C kama vile katika 773 00:32:04,510 --> 00:32:05,230 lugha nyingine. 774 00:32:05,230 --> 00:32:08,480 Char, kama jina linavyosema, ni tu tabia moja. 775 00:32:08,480 --> 00:32:12,150 kuelea ni floating kumweka thamani, na kwamba tu dhana 776 00:32:12,150 --> 00:32:14,470 njia ya kusema idadi halisi - kitu ambacho hakina decimal 777 00:32:14,470 --> 00:32:17,410 uhakika katika hilo na idadi ya baadhi ya kushoto na / au kulia. 778 00:32:17,410 --> 00:32:21,370 int ni integer, ambayo ni idadi tu kama 123. 779 00:32:21,370 --> 00:32:24,170 Na sasa zaidi linalovutia ni mambo kama mara mbili. 780 00:32:24,170 --> 00:32:28,540 Nini sisi kusema mara mbili mara ya mwisho wakati? 781 00:32:28,540 --> 00:32:30,050 Ni 64, haki. 782 00:32:30,050 --> 00:32:33,560 Hivyo ambapo kawaida kuelea ni 32-bit - 783 00:32:33,560 --> 00:32:37,340 hivyo ni hii ya muda mrefu katika kumbukumbu, inatumia zeros 32 na ndio 784 00:32:37,340 --> 00:32:40,530 kuwakilisha maadili - mara mbili ni literally mara mbili, ambayo 785 00:32:40,530 --> 00:32:43,810 ina maana kuwa unaweza ama kuwakilisha idadi kubwa zaidi, au 786 00:32:43,810 --> 00:32:45,810 unaweza kuwakilisha idadi sahihi zaidi. 787 00:32:45,810 --> 00:32:48,690 Hivyo unaweza kuwa na idadi zaidi baada ya uhakika decimal, lakini 788 00:32:48,690 --> 00:32:51,520 kama wenzake alisema katika video, hata kitu rahisi 789 00:32:51,520 --> 00:32:55,360 conceptually kama 1/3 haiwezi kuwakilishwa just kwa 790 00:32:55,360 --> 00:32:58,330 kompyuta, kwa sababu hatimaye kukimbia nje ya bits, na 791 00:32:58,330 --> 00:33:02,510 Basi unaweza tu kufanya hivyo mara nyingi .33333333, katika 792 00:33:02,510 --> 00:33:05,050 ambayo uhakika wewe tu kusema mimi nina nje ya uwakilishi 793 00:33:05,050 --> 00:33:08,120 nafasi, nina tu kuiita siku na kuiwakilisha 794 00:33:08,120 --> 00:33:10,200 kiasi fulani imprecisely kama hiyo. 795 00:33:10,200 --> 00:33:11,110 Na muda mrefu - 796 00:33:11,110 --> 00:33:13,880 kijinga jina, lakini ni kwa sababu kuna data aina inayojulikana kama 797 00:33:13,880 --> 00:33:19,350 muda mrefu katika C ambayo ni mara nyingi 32 coincidentally bits, kama tu 798 00:33:19,350 --> 00:33:21,670 int ni 32 bits, lakini muda mrefu ni 799 00:33:21,670 --> 00:33:23,560 ujumla 64 bits. 800 00:33:23,560 --> 00:33:25,740 Hivyo njia tu unaweza kuwakilisha kubwa 801 00:33:25,740 --> 00:33:26,990 idadi zaidi kuliko huu. 802 00:33:26,990 --> 00:33:27,410 >> Wote haki. 803 00:33:27,410 --> 00:33:29,390 Hivyo kama sisi kweli unataka kuanza anayewakilisha mambo, sisi 804 00:33:29,390 --> 00:33:31,030 kuhitaji zaidi aina ya kisasa, na 805 00:33:31,030 --> 00:33:32,340 hiyo ndiyo sababu tuna kamba. 806 00:33:32,340 --> 00:33:36,450 Hivyo katika maktaba CS50, kwamba faili inayoitwa cs50.h, tumekuwa 807 00:33:36,450 --> 00:33:41,110 kweli alitangaza data aina, hivyo kusema, iitwayo kamba, 808 00:33:41,110 --> 00:33:42,710 lakini kamba si kweli zipo. 809 00:33:42,710 --> 00:33:44,780 Hii ni mara ya pili, moja ya tabaka hizi tunakwenda peel 810 00:33:44,780 --> 00:33:47,490 nyuma katika wiki moja au mbili na kutupa mbali, na kwa kweli 811 00:33:47,490 --> 00:33:49,640 kuangalia chini ya Hood katika kile string kweli ni, na 812 00:33:49,640 --> 00:33:50,840 jinsi gani kuwakilishwa. 813 00:33:50,840 --> 00:33:53,520 Sisi ni pia kwenda kuangalia maadili Boolean. 814 00:33:53,520 --> 00:33:56,040 >> Basi nini ilikuwa bool katika muktadha wa Scratch? 815 00:33:59,154 --> 00:34:00,300 Ni kweli au uongo. 816 00:34:00,300 --> 00:34:03,900 Hivyo ni thamani tu kwamba ni kweli au uongo, juu au mbali, 1 au 817 00:34:03,900 --> 00:34:06,140 0, hata hivyo unataka kuona dunia. 818 00:34:06,140 --> 00:34:09,739 Hivyo katika C, shukrani kwa maktaba CS50, ambayo kwa upande 819 00:34:09,739 --> 00:34:12,179 ni pamoja na mwingine maktaba chini ya Hood, tuna 820 00:34:12,179 --> 00:34:14,909 upatikanaji wa data aina hiyo iitwayo bool, ambayo itakuwa 821 00:34:14,909 --> 00:34:18,730 literally kuruhusu sisi hawawajui maadili kweli au uongo kwa 822 00:34:18,730 --> 00:34:20,219 mambo katika mpango. 823 00:34:20,219 --> 00:34:23,880 >> Basi hebu kwenda mbele hapa na kuandika mpango kidogo kwamba 824 00:34:23,880 --> 00:34:26,330 haina kitu kuwashirikisha idadi badala yake. 825 00:34:26,330 --> 00:34:29,840 Hivyo basi mimi kurejea Appliance CS50, napenda kwenda mbele na 826 00:34:29,840 --> 00:34:32,770 kuunda faili mpya hapa inaitwa - 827 00:34:32,770 --> 00:34:35,460 hebu sema tu kitu rahisi, kama math.c. 828 00:34:38,270 --> 00:34:38,710 Wote haki. 829 00:34:38,710 --> 00:34:41,600 Na sasa kwenda hadi juu ya mpango wangu, mimi nina 830 00:34:41,600 --> 00:34:42,510 kwenda kufanya kawaida - 831 00:34:42,510 --> 00:34:44,780 # Pamoja , ili niweze kutumia 832 00:34:44,780 --> 00:34:46,860 printf, int kuu (utupu) - 833 00:34:46,860 --> 00:34:49,270 tutaweza kurudi, hatimaye, nini maana ya int 834 00:34:49,270 --> 00:34:52,389 hapa, nini maana ya utupu hapa, lakini kwa sasa, tu kujua kwamba 835 00:34:52,389 --> 00:34:54,270 una kuanza programu kama hii. 836 00:34:54,270 --> 00:34:56,280 Sasa mimi nina kwenda mbele na kusema kitu kidogo 837 00:34:56,280 --> 00:35:02,110 tofauti - printf ("Nipe namba:" 838 00:35:02,110 --> 00:35:03,570 );. 839 00:35:03,570 --> 00:35:09,220 Kisha mimi naenda kufanya int n = GetInt, kwa sababu ni 840 00:35:09,220 --> 00:35:12,770 zamu nje GetInt ni kazi nyingine katika maktaba CS50 841 00:35:12,770 --> 00:35:14,060 badala GetString. 842 00:35:14,060 --> 00:35:17,340 Na sasa mimi naenda kufanya kitu kijinga, kama "shukrani 843 00:35:17,340 --> 00:35:25,760 kwa d%, "kwa ajili ya decimal integer, na kisha n comma, na 844 00:35:25,760 --> 00:35:26,620 kisha kurudi 0. 845 00:35:26,620 --> 00:35:28,940 Hivyo tena, kurudi 0 hauhusiani na idadi mimi nina 846 00:35:28,940 --> 00:35:30,080 kuuliza mtumiaji kwa ajili ya. 847 00:35:30,080 --> 00:35:33,620 Tu kunaashiria mwishoni kwamba wote, labda, ni vizuri. 848 00:35:33,620 --> 00:35:36,290 >> Hivyo basi mimi kwenda chini kwa terminal dirisha yangu hapa. 849 00:35:36,290 --> 00:35:39,590 Hebu aina kufanya math, kuingia. 850 00:35:39,590 --> 00:35:41,360 Na kitu kibaya. 851 00:35:41,360 --> 00:35:44,620 Kufanya math hawakuwa na kazi. 852 00:35:44,620 --> 00:35:46,170 Hapa ni ya kwanza ya ujumbe wetu kosa. 853 00:35:46,170 --> 00:35:46,570 Kwa nini? 854 00:35:46,570 --> 00:35:49,720 cryptic kidogo, lakini - 855 00:35:49,720 --> 00:35:50,060 Yeah. 856 00:35:50,060 --> 00:35:51,240 Hivyo cs50.h. 857 00:35:51,240 --> 00:35:53,900 Hivyo tena, hasa mapema, utapata kuandika yako ya kwanza 858 00:35:53,900 --> 00:35:56,590 mpango kwa pset 1 katika sehemu, katika ofisi ya masaa, na 859 00:35:56,590 --> 00:35:59,050 shahiri, utakuwa ni balaa wakati mwingine mambo haya 860 00:35:59,050 --> 00:36:00,000 ni kweli kusema. 861 00:36:00,000 --> 00:36:01,890 Lakini utasikia kutambua haraka sana wao kuanza kuanguka 862 00:36:01,890 --> 00:36:06,120 ndani ya ndoo ambapo hii moja ina maana kwamba ve kushoto mbali moja 863 00:36:06,120 --> 00:36:08,290 wa ni pamoja na # ya wakati juu ya faili. 864 00:36:08,290 --> 00:36:10,960 Na Clang, mkusanyaji, ni taarifa yenu ya hii na 865 00:36:10,960 --> 00:36:14,090 akisema, badala fancifully, thabiti tamko la 866 00:36:14,090 --> 00:36:15,990 kazi GetInt ni batili. 867 00:36:15,990 --> 00:36:16,310 >> Wote haki. 868 00:36:16,310 --> 00:36:17,520 Hiyo ni nini maana ya kwamba? 869 00:36:17,520 --> 00:36:22,080 Ni njia tu ve implicitly alitangaza GetInt katika 870 00:36:22,080 --> 00:36:24,850 hisia kwamba wewe si wazi amekiri kuwa ni. 871 00:36:24,850 --> 00:36:27,300 Kupanga kutangaza int, una kufundisha 872 00:36:27,300 --> 00:36:28,740 Clang kwamba ipo. 873 00:36:28,740 --> 00:36:32,020 Na ufumbuzi rahisi sana kwa kuwa ni kufundisha na 874 00:36:32,020 --> 00:36:34,780 ikiwa ni pamoja na faili hii nyingine, cs50.h, katika 875 00:36:34,780 --> 00:36:35,850 juu ya faili yako. 876 00:36:35,850 --> 00:36:40,380 Kwa sababu halisi, nini ni pamoja # haina ni inavyo Clang 877 00:36:40,380 --> 00:36:44,030 pretty kiasi cha kwenda kupata faili inayoitwa cs50.h, nakala, 878 00:36:44,030 --> 00:36:48,150 kuweka ni moja kwa moja ndani ya juu ya mpango wangu kwa ajili yangu, 879 00:36:48,150 --> 00:36:50,850 na kisha kuwabadili source code kwa zeros na ndio. 880 00:36:50,850 --> 00:36:52,850 Lakini kwamba itakuwa ni wazi kuwa tedious sana kama sisi binadamu alikuwa 881 00:36:52,850 --> 00:36:55,370 kwenda kuiga na pasting hizi files kubwa wakati wote, 882 00:36:55,370 --> 00:36:58,540 hivyo ni pamoja # tu anafanya yote kuwa moja kwa moja bila 883 00:36:58,540 --> 00:37:01,550 muddying code yangu na maktaba ya mtu mwingine. 884 00:37:01,550 --> 00:37:06,370 Na maktaba ni mwingine tu file zenye majukumu na 885 00:37:06,370 --> 00:37:08,340 mambo mengine ambayo mtu mwingine ameandika, kwamba sisi ni 886 00:37:08,340 --> 00:37:10,270 leveraging kwa ajili yetu wenyewe. 887 00:37:10,270 --> 00:37:10,580 >> Wote haki. 888 00:37:10,580 --> 00:37:11,200 Hebu jaribu tena. 889 00:37:11,200 --> 00:37:12,250 Kufanya math. 890 00:37:12,250 --> 00:37:13,120 Kuingia. 891 00:37:13,120 --> 00:37:13,530 Nzuri. 892 00:37:13,530 --> 00:37:14,880 Hivyo kwamba inaonekana kuwa na kazi. 893 00:37:14,880 --> 00:37:18,330 Hivyo basi mimi sasa kukimbia math; / math.. 894 00:37:18,330 --> 00:37:21,100 Ingiza anitiaye idadi, 123. 895 00:37:21,100 --> 00:37:22,620 Shukrani kwa 123. 896 00:37:22,620 --> 00:37:24,490 Sasa hebu jaribu kesi nyingine kona. 897 00:37:24,490 --> 00:37:26,530 kamba ni pretty ukarimu, kwa sababu 898 00:37:26,530 --> 00:37:27,620 kamba inaweza kuwa kitu chochote. 899 00:37:27,620 --> 00:37:28,910 Inaweza kuangalia kama namba, kuangalia kama 900 00:37:28,910 --> 00:37:30,600 wahusika, kuangalia kama maneno. 901 00:37:30,600 --> 00:37:31,900 Lakini int ni int. 902 00:37:31,900 --> 00:37:34,370 Hivyo sasa kama nina mtumiaji vigumu, na ni kusema "Nipe 903 00:37:34,370 --> 00:37:38,730 idadi, "nini kama mimi kujaribu kufanya kitu kama 0.1? 904 00:37:38,730 --> 00:37:41,510 Naam, hiyo ni idadi, na ni thabiti na 905 00:37:41,510 --> 00:37:44,180 sarufi mimi kutumika hapa, lakini chini ya Hood, mimi nina ya 906 00:37:44,180 --> 00:37:45,610 Bila shaka kutumia GetInt kazi. 907 00:37:45,610 --> 00:37:46,610 >> Basi hebu angalia nini kinatokea. 908 00:37:46,610 --> 00:37:48,250 Kuingia, jaribu tena. 909 00:37:48,250 --> 00:37:48,560 Wote haki. 910 00:37:48,560 --> 00:37:50,570 Hebu kuwa vigumu na tu hit Enter tena. 911 00:37:50,570 --> 00:37:51,700 Kuingia, Ingiza. 912 00:37:51,700 --> 00:37:53,890 Hivyo sasa inaonekana GetInt, ambayo ni kidogo zaidi 913 00:37:53,890 --> 00:37:55,240 nguvu zaidi kuliko GetString. 914 00:37:55,240 --> 00:37:58,540 Sisi, wafanyakazi, kutekelezwa katika njia kwamba kama sisi taarifa vile 915 00:37:58,540 --> 00:38:02,100 wewe si ametupa int - na int ni idadi decimal 916 00:38:02,100 --> 00:38:04,785 zenye zeros, ndio, wawili-wawili, watatu, wane, na umri wa miaka mitano, sixes, 917 00:38:04,785 --> 00:38:05,540 saba saba, eights, au nines. 918 00:38:05,540 --> 00:38:06,310 Na kwamba ni. 919 00:38:06,310 --> 00:38:08,810 Hakuna pointi decimal, hakuna wahusika, hakuna alama za uakifishi. 920 00:38:08,810 --> 00:38:10,390 Inaonekana kwamba tuna kushirikiana. 921 00:38:10,390 --> 00:38:13,680 Hivyo basi mimi kujaribu nne, tano, sita, na kwamba anapata mimi kwa kupitia. 922 00:38:13,680 --> 00:38:16,760 Hivyo kweli, kuwa anal hapa, mimi lazima pengine kusema "Nipe 923 00:38:16,760 --> 00:38:20,310 integer "ili kufikisha kwa mtumiaji 924 00:38:20,310 --> 00:38:22,620 hasa nini mimi na nia. 925 00:38:22,620 --> 00:38:24,090 >> Sasa hebu fikiria kuhusu chini ya Hood. 926 00:38:24,090 --> 00:38:27,930 Sisi siyo kwenda kuangalia jinsi cs50.h ni kutekelezwa leo, 927 00:38:27,930 --> 00:38:29,080 kwamba maktaba. 928 00:38:29,080 --> 00:38:33,600 Lakini kama ni kuvaa akisema retry, retry, retry, nini programu 929 00:38:33,600 --> 00:38:36,970 kujenga mimi labda kwa kutumia chini ya Hood kwa 930 00:38:36,970 --> 00:38:39,000 kutekeleza hilo? 931 00:38:39,000 --> 00:38:39,980 Hivyo tu kitanzi, haki? 932 00:38:39,980 --> 00:38:41,930 Moja ya mawazo rahisi kuwa tuliona juu ya Scratch. 933 00:38:41,930 --> 00:38:45,050 Forever kujenga, Rudia kujenga. 934 00:38:45,050 --> 00:38:47,320 Labda, katika mpango huu, chini ya Hood, hata 935 00:38:47,320 --> 00:38:49,470 ingawa Imeandikwa katika C na si scratch, ni kufanya 936 00:38:49,470 --> 00:38:54,300 kitu kinachoitwa sawa na milele kama mtumiaji hana 937 00:38:54,300 --> 00:38:58,710 typed katika integer, kusema retry, retry, retry, retry, hivyo 938 00:38:58,710 --> 00:39:01,220 kisha hatimaye wakati sisi kufanya kupata integer, basi 939 00:39:01,220 --> 00:39:02,970 kuvunja nje ya kitanzi kwamba. 940 00:39:02,970 --> 00:39:05,610 >> Basi nini kazi nyingine tunaweza kutumia hapa katika maktaba CS50 wa? 941 00:39:05,610 --> 00:39:07,880 Naam, aina ya wale wa dhahiri, angalau kwa kuzingatia 942 00:39:07,880 --> 00:39:09,570 data aina ya kwamba sisi sasa kujua kuwepo. 943 00:39:09,570 --> 00:39:12,900 Sisi kutekelezwa GetString, GetInt, lakini katika 944 00:39:12,900 --> 00:39:15,680 kwanza ya wiki ya muda, unaweza pia kutumia GetFloat na 945 00:39:15,680 --> 00:39:18,870 GetDouble na GetLongLong ili kupata usahihi 946 00:39:18,870 --> 00:39:20,030 data aina kwamba unataka. 947 00:39:20,030 --> 00:39:24,030 Kwa sababu undani muhimu hapa ni kuwa tofauti na baadhi ya lugha, 948 00:39:24,030 --> 00:39:26,630 kama Chatu na Ruby, ambapo huna lazima kuwa na 949 00:39:26,630 --> 00:39:29,730 kutangaza data aina ya kutofautiana - 950 00:39:29,730 --> 00:39:32,390 huna kuiambia kompyuta nini aina ya mambo ya 951 00:39:32,390 --> 00:39:34,000 utaenda kuweka katika variable - 952 00:39:34,000 --> 00:39:36,640 katika C, una kuwa milele hivyo sahihi. 953 00:39:36,640 --> 00:39:40,060 Hivyo kama unataka variable kuitwa n, chunk ya kuhifadhi 954 00:39:40,060 --> 00:39:42,900 kwamba katika kesi hii hutokea kwa kuwa 32 bits na mkataba, wewe 955 00:39:42,900 --> 00:39:45,660 tuwaeleze kompyuta kwamba hawa bits ni 956 00:39:45,660 --> 00:39:47,840 kwenda kuhifadhi idadi - 957 00:39:47,840 --> 00:39:50,630 si tabia, si kamba, si kuelea. 958 00:39:50,630 --> 00:39:52,620 Na hii anwani suala sisi kwa ufanisi 959 00:39:52,620 --> 00:39:53,760 mbio katika wiki ya mwisho. 960 00:39:53,760 --> 00:39:57,050 Kama sisi ni kutumia zeros na idadi ndio kuwakilisha sio tu 961 00:39:57,050 --> 00:40:00,770 idadi lakini Kama na Bs na Cs, jinsi katika dunia ni 962 00:40:00,770 --> 00:40:03,460 kompyuta kwenda kujua kwamba muundo huu wa bits kweli 963 00:40:03,460 --> 00:40:07,650 inawakilisha idadi 65, kinyume na anayewakilisha 964 00:40:07,650 --> 00:40:09,860 barua A, ambayo kwa bahati, kulingana na 965 00:40:09,860 --> 00:40:13,440 ASCII, kukumbuka, ilikuwa sawa na 65? 966 00:40:13,440 --> 00:40:16,550 >> Hivyo aina ya data hizi kutoa muktadha wa kompyuta, hivyo 967 00:40:16,550 --> 00:40:18,810 kwamba anajua kama bits hizi lazima kufasiriwa kama 968 00:40:18,810 --> 00:40:23,660 int au kama kamba. 969 00:40:23,660 --> 00:40:26,500 Maswali yoyote, basi, juu ya hili? 970 00:40:26,500 --> 00:40:28,149 Yeah? 971 00:40:34,780 --> 00:40:35,270 DAVID J. Malan: Good swali. 972 00:40:35,270 --> 00:40:39,140 Kama sisi kuchukua nje stdio.h, sisi ila faili - 973 00:40:39,140 --> 00:40:44,360 napenda kwenda chini kwa dirisha terminal na kukimbia kufanya math, zoom 974 00:40:44,360 --> 00:40:45,530 katika na kuingia - 975 00:40:45,530 --> 00:40:47,700 sasa mimi kupata kosa tofauti, kwa sababu mimi nina implicitly 976 00:40:47,700 --> 00:40:49,650 wakieleza kazi sasa? 977 00:40:49,650 --> 00:40:50,700 Printf. 978 00:40:50,700 --> 00:40:52,970 Hivyo sasa nimekuwa umba tatizo mpya, ambao ni suluhisho 979 00:40:52,970 --> 00:40:53,890 kimsingi huo. 980 00:40:53,890 --> 00:40:55,365 Nahitaji kuweka kwamba nyuma. 981 00:40:55,365 --> 00:40:56,615 Watazamaji: [inaudible] 982 00:41:03,534 --> 00:41:04,030 DAVID J. Malan: Oh. 983 00:41:04,030 --> 00:41:04,850 Hivyo kama mimi kuchukua nje - 984 00:41:04,850 --> 00:41:05,360 Okay, yeah. 985 00:41:05,360 --> 00:41:08,960 Hivyo kama mimi kuondoa kuingizwa kiwango I / O maktaba hadi 986 00:41:08,960 --> 00:41:12,020 hapa, na kisha wewe kusema kama mimi kujikwamua printf, kupata 987 00:41:12,020 --> 00:41:13,450 kuondoa ya printf? 988 00:41:13,450 --> 00:41:13,810 Ndiyo. 989 00:41:13,810 --> 00:41:18,450 Hii lazima kazi, kwa sababu mimi nina tena kutumia yoyote - Lo. 990 00:41:18,450 --> 00:41:20,110 Je, mimi tu uongo? 991 00:41:20,110 --> 00:41:21,650 Oh, sawa. 992 00:41:21,650 --> 00:41:25,640 Hii si kazi kwa sababu ya hitilafu mpya sisi tu vishawishi. 993 00:41:25,640 --> 00:41:28,390 Na hii ni moja ya kidogo zaidi self-maelezo. 994 00:41:28,390 --> 00:41:29,440 >> Nini tatizo? 995 00:41:29,440 --> 00:41:30,680 Isiyotumika variable n. 996 00:41:30,680 --> 00:41:34,040 Hivyo kosa hili ni matokeo ya yetu kuwa configured 997 00:41:34,040 --> 00:41:36,640 appliance kuwa hasa pedantic, kwa kweli yell katika 998 00:41:36,640 --> 00:41:39,060 wewe kwa kila kosa iwezekanavyo, hata kama ni aina ya 999 00:41:39,060 --> 00:41:41,950 makosa yasiyo mbaya kama hii - ni kweli kubwa vile 1000 00:41:41,950 --> 00:41:44,820 kukabiliana kwamba mimi zilizotengwa int, kuweka idadi ndani yake, na kisha 1001 00:41:44,820 --> 00:41:46,030 tu walifanya chochote kwa hayo? 1002 00:41:46,030 --> 00:41:47,020 Hivyo functionally, hakuna. 1003 00:41:47,020 --> 00:41:50,410 Hiyo si kwenda kuvunja mpango. 1004 00:41:50,410 --> 00:41:51,490 Ni aina tu ya kijinga, haki? 1005 00:41:51,490 --> 00:41:54,220 Hakuna thamani kwa akaomba kwamba idadi hiyo, kuhifadhiwa 1006 00:41:54,220 --> 00:41:56,370 ni katika variable, kama wewe ni kamwe kwenda kufanya kitu chochote 1007 00:41:56,370 --> 00:41:58,000 pamoja na hayo, kama magazeti au atayaokoa. 1008 00:41:58,000 --> 00:42:00,270 Hivyo katika kesi hii, Clang ni kutambua kama mengi, na 1009 00:42:00,270 --> 00:42:02,010 ni kusema n outnyttjade kutofautiana. 1010 00:42:02,010 --> 00:42:05,380 >> Hivyo tunaweza kurekebisha hii ikiwa kweli tunataka. 1011 00:42:05,380 --> 00:42:07,250 Lakini tena, hii si nzuri ya programu sasa. 1012 00:42:07,250 --> 00:42:09,310 Hivyo mimi nilikuwa tu kufanya hivyo - 1013 00:42:09,310 --> 00:42:12,060 kwenda chini hapa, basi mimi wazi screen, kufanya math. 1014 00:42:12,060 --> 00:42:13,090 Kwamba kazi. 1015 00:42:13,090 --> 00:42:18,110 Sasa siwezi kukimbia math yangu mpango, inachukua pembejeo - 1016 00:42:18,110 --> 00:42:18,700 vizuri, kwamba ilikuwa mbaya. 1017 00:42:18,700 --> 00:42:23,450 Inachukua pembejeo, na kwamba ni wote ni sawa, katika kesi hii. 1018 00:42:23,450 --> 00:42:25,220 >> Hivyo kweli, hebu jaribu moja nyingine kona kesi ya kwamba sisi 1019 00:42:25,220 --> 00:42:26,300 hakufikiri wa mapema. 1020 00:42:26,300 --> 00:42:28,220 Katika kesi hii - hapa, hebu kwenda nyuma ya moja ambayo 1021 00:42:28,220 --> 00:42:29,500 kidogo zaidi user-kirafiki. 1022 00:42:29,500 --> 00:42:32,580 Hebu nirejee nyuma hapa na kukimbia kufanya math tena. 1023 00:42:32,580 --> 00:42:34,190 Whoops, nini mimi kufanya makosa? 1024 00:42:34,190 --> 00:42:35,400 Got nirudishe zaidi. 1025 00:42:35,400 --> 00:42:36,390 Sawa. 1026 00:42:36,390 --> 00:42:38,490 Sasa tuko nyuma katika hali ya awali, ambapo wote 1027 00:42:38,490 --> 00:42:39,990 ni hopefully vizuri. 1028 00:42:39,990 --> 00:42:43,360 Na sasa kama mimi kukimbia math, 123 inaonekana kazi. 1029 00:42:43,360 --> 00:42:46,010 Lakini hii si kweli ushahidi madhubuti, kwa kusema tu 1030 00:42:46,010 --> 00:42:47,930 sawa, kwamba kazi. 1031 00:42:47,930 --> 00:42:49,120 789, kwamba kazi. 1032 00:42:49,120 --> 00:42:50,100 Muda wa kuwasilisha. 1033 00:42:50,100 --> 00:42:51,870 Kwa sababu kuna wengine kona kesi hapa. 1034 00:42:51,870 --> 00:42:55,040 kamba si kweli kutupa shida sana kwa kuandika katika 1035 00:42:55,040 --> 00:42:56,510 zima mengi ya wahusika. 1036 00:42:56,510 --> 00:42:59,580 Lakini nini kama mimi aina katika hili? 1037 00:42:59,580 --> 00:43:04,850 Kupiga namba 1 mengi yote, nzima mengi hapa - 1038 00:43:04,850 --> 00:43:06,300 haki zote, ni kupata boring kidogo, hivyo mimi nina kwenda 1039 00:43:06,300 --> 00:43:10,040 kusimama hapa, na mimi nina kwenda hit Enter. 1040 00:43:10,040 --> 00:43:11,290 >> Nini kuzimu tu kilichotokea? 1041 00:43:14,110 --> 00:43:17,680 Hivyo hii kweli anaweza alielezea. 1042 00:43:17,680 --> 00:43:18,920 Hivyo alifanya hivyo kuchukua ni kama binary? 1043 00:43:18,920 --> 00:43:21,130 mawazo mazuri, lakini hakuna, siyo kweli kwamba alichukua 1044 00:43:21,130 --> 00:43:22,815 kama binary, kwa sababu kwa kweli, kwamba ilikuwa tu aina ya 1045 00:43:22,815 --> 00:43:23,080 bahati mbaya. 1046 00:43:23,080 --> 00:43:23,930 Tunaweza kufanya hii tena. 1047 00:43:23,930 --> 00:43:26,530 Hivyo hakuna 2 katika mfumo binary, hiyo ni 1048 00:43:26,530 --> 00:43:27,420 pengine kutosha anyway. 1049 00:43:27,420 --> 00:43:28,780 Kuingia. 1050 00:43:28,780 --> 00:43:30,140 Hivyo hiyo haikuwa tatizo. 1051 00:43:30,140 --> 00:43:31,390 Gani kingine? 1052 00:43:34,650 --> 00:43:35,400 Hasa. 1053 00:43:35,400 --> 00:43:37,830 >> Hivyo kufikiri nyuma kwa nini int kweli ni. 1054 00:43:37,830 --> 00:43:40,970 Ni 32 bits ambazo kwa pamoja ni kufasiriwa 1055 00:43:40,970 --> 00:43:42,090 kama idadi. 1056 00:43:42,090 --> 00:43:44,730 Kama una bits 32, kwamba maana kila bits inaweza kuwa 1057 00:43:44,730 --> 00:43:46,690 0 au 1, 0 au 1. 1058 00:43:46,690 --> 00:43:49,090 Hivyo kwamba maana kuna uwezekano mbili kwa kidogo hii, 1059 00:43:49,090 --> 00:43:51,140 mbili uwezekano kwa ajili ya hii, wawili uwezekano huu 1060 00:43:51,140 --> 00:43:52,570 kidogo - hivyo ndiyo 2 kuzidisha kwa 2 - 1061 00:43:52,570 --> 00:43:55,480 hivyo ndiyo 2 kwa nguvu 32 ni jumla ya idadi ya 1062 00:43:55,480 --> 00:43:58,960 permutations ya zeros na ndio kama una 32 1063 00:43:58,960 --> 00:44:01,400 placeholders, zeros au ndio, mbele yenu. 1064 00:44:01,400 --> 00:44:04,250 Hivyo kama nina 2-32, kihisabati, kwamba ni nini? 1065 00:44:07,080 --> 00:44:07,840 Hivyo ni mengi. 1066 00:44:07,840 --> 00:44:09,910 Ni bilioni 4, kutoa au kuchukua. 1067 00:44:09,910 --> 00:44:13,510 Bilioni 4 na haionekani kuwa kile kuchapishwa hapa. 1068 00:44:13,510 --> 00:44:16,290 Kwa kweli, hii inaonekana karibu na bilioni 2. 1069 00:44:16,290 --> 00:44:17,970 Lakini hii si bahati mbaya. 1070 00:44:17,970 --> 00:44:21,590 ukweli kwamba kompyuta ina misinterpreted namba yangu mkubwa, 1071 00:44:21,590 --> 00:44:24,260 mlolongo yangu kubwa ya wale na kisha mlolongo yangu kubwa ya wawiliwawili, 1072 00:44:24,260 --> 00:44:26,880 kama takribani bilioni 2, ni alielezea jinsi gani? 1073 00:44:30,250 --> 00:44:32,180 Kuna cap juu int. 1074 00:44:32,180 --> 00:44:34,970 Kuna hakika thamani ya kiwango cha kuwa unaweza kuwakilisha. 1075 00:44:34,970 --> 00:44:36,370 Lakini ni kawaida bilioni 4, sawa? 1076 00:44:36,370 --> 00:44:39,100 Kama 2-32 ni takribani bilioni 4, kwamba inaonekana kama 1077 00:44:39,100 --> 00:44:40,350 hiyo ni idadi kubwa. 1078 00:44:42,420 --> 00:44:45,240 Hivyo si salio, lakini mawazo mazuri. 1079 00:44:45,240 --> 00:44:46,340 Hasi idadi. 1080 00:44:46,340 --> 00:44:49,570 Hivyo kama una bilioni 4 mambo iwezekanavyo unaweza 1081 00:44:49,570 --> 00:44:52,970 kuwakilisha na permutations haya mbalimbali ya sekunde 0 32 na 1082 00:44:52,970 --> 00:44:55,600 1s, vizuri, anasimama kwa sababu ya kuwa sisi binadamu kutaka 1083 00:44:55,600 --> 00:44:57,110 kuwakilisha sio tu integers chanya 1084 00:44:57,110 --> 00:44:58,240 lakini hasi integers. 1085 00:44:58,240 --> 00:45:00,410 Na kwa kweli, hilo ni wazo kuwa C hufanya. 1086 00:45:00,410 --> 00:45:03,550 Hivyo, pamoja na bits 32, unaweza kuwakilisha takribani hasi 2 1087 00:45:03,550 --> 00:45:06,630 bilioni wote njia hadi chanya bilioni 2. 1088 00:45:06,630 --> 00:45:08,750 Na hivyo katika kesi hii, kile sisi ni kweli kuona ni tu 1089 00:45:08,750 --> 00:45:13,600 pindo ya uwezo wa integer yetu, na sisi, hivyo 1090 00:45:13,600 --> 00:45:15,860 kuzungumza, ilifurika integer. 1091 00:45:15,860 --> 00:45:19,180 Tumejaribu kwa cram bits zaidi ndani yake kuliko unaweza kweli inafaa. 1092 00:45:19,180 --> 00:45:22,960 Hivyo matokeo ya mwisho ni sisi kimsingi kuwa na bits wote 1. 1093 00:45:22,960 --> 00:45:25,280 Tumekuwa flipped wote wa bits yetu juu, tumekuwa alijaribu kuwakilisha 1094 00:45:25,280 --> 00:45:27,630 idadi kubwa iwezekanavyo, lakini ni wazi si karibu 1095 00:45:27,630 --> 00:45:30,960 kubwa ya kutosha kuwakilisha mambo mawili nimekuwa tu typed in 1096 00:45:30,960 --> 00:45:31,730 Yeah? 1097 00:45:31,730 --> 00:45:32,980 Watazamaji: [inaudible] 1098 00:45:37,230 --> 00:45:37,830 >> DAVID J. Malan: Good swali. 1099 00:45:37,830 --> 00:45:40,080 Kwa nini hatuwezi tu kuwakilisha kwamba hasi 1100 00:45:40,080 --> 00:45:41,500 saini kama tu tabia? 1101 00:45:41,500 --> 00:45:44,200 Hivyo sisi kabisa alivyoweza, na tunaweza kisha kuokoa 1102 00:45:44,200 --> 00:45:45,470 kidogo ya ziada. 1103 00:45:45,470 --> 00:45:49,100 Lakini bado uko kwenda na kuwakilisha kwamba dash, na 1104 00:45:49,100 --> 00:45:50,700 ambayo inaenda gharama angalau kitu, 1105 00:45:50,700 --> 00:45:52,220 labda kidogo. 1106 00:45:52,220 --> 00:45:55,610 Hivyo ndiyo, tunaweza kuwa na bits 32 kutumika kwa ajili ya idadi yetu, lakini sasa 1107 00:45:55,610 --> 00:45:57,610 tunahitaji mwingine kidogo kutumika kwa ajili ya dash wetu 1108 00:45:57,610 --> 00:45:58,810 ishara, ishara bala. 1109 00:45:58,810 --> 00:46:01,470 Hivyo basi, tuna 33 maadili kidogo, ambayo tunaweza kufanya, lakini ni 1110 00:46:01,470 --> 00:46:02,570 si tu njia ni kosa. 1111 00:46:02,570 --> 00:46:05,140 Sisi alifanya hukumu wito miaka iliyopita, 32 bits ni aina ya 1112 00:46:05,140 --> 00:46:06,170 kitengo cha kipimo hapa. 1113 00:46:06,170 --> 00:46:08,120 Hivyo sisi ni kwenda kutumia moja ya bits wale ufanisi kwa 1114 00:46:08,120 --> 00:46:12,950 kuwakilisha negativity, na bits 31 kuwakilisha idadi. 1115 00:46:12,950 --> 00:46:15,550 Maswali mengine? 1116 00:46:15,550 --> 00:46:15,670 Wote haki. 1117 00:46:15,670 --> 00:46:16,030 Hiyo ni mengi. 1118 00:46:16,030 --> 00:46:17,930 Mbona sisi kwenda mbele na kuchukua yetu dakika tano mapumziko hapa? 1119 00:46:23,580 --> 00:46:24,270 >> Wote haki. 1120 00:46:24,270 --> 00:46:31,250 Hivyo tena, si kwa overemphasize maombi ya hisabati 1121 00:46:31,250 --> 00:46:33,840 ya programu, hebu tu konoa mfano huu mmoja 1122 00:46:33,840 --> 00:46:36,590 kabla ya kuendelea katika constructs nyingine, kwa sababu tu 1123 00:46:36,590 --> 00:46:39,430 itaonyesha chache kawaida pointi kikwazo juu ya baadhi ya 1124 00:46:39,430 --> 00:46:41,520 misingi linapokuja programu kuandika. 1125 00:46:41,520 --> 00:46:44,360 Katika kesi hii, kufanya hesabu misemo kwamba kuwa na baadhi ya 1126 00:46:44,360 --> 00:46:48,010 kuvutia umuhimu kwa syntax. 1127 00:46:48,010 --> 00:46:50,430 >> Hivyo hii ni tu formula ambayo tunaweza kuwabadili 1128 00:46:50,430 --> 00:46:52,690 joto kutoka Fahrenheit kwa Celsius. 1129 00:46:52,690 --> 00:46:54,600 Kama wewe si unakumbuka, hii ni formula. 1130 00:46:54,600 --> 00:46:58,870 Hivyo kama sisi kuziba katika Fahrenheit thamani ya digrii 32, ambayo ni 1131 00:46:58,870 --> 00:47:02,850 kufungia, kwamba ni kwenda kuwa 32 minus 32 ni 0, na kwa kweli, 1132 00:47:02,850 --> 00:47:05,130 0 katika Celsius pia ni kufungia. 1133 00:47:05,130 --> 00:47:08,210 Hivyo sanity haraka kuangalia pale - kwamba ni formula familiar. 1134 00:47:08,210 --> 00:47:10,880 Nivuke kwa appliance, ingawa, na kuanza 1135 00:47:10,880 --> 00:47:13,920 kuandika mpango ujulikanao kama, f2c; "Fahrenheit kwa 1136 00:47:13,920 --> 00:47:15,920 Celsius dot c ". 1137 00:47:15,920 --> 00:47:18,930 Na juu kwa juu hapa, mimi naenda kuanza mbali na ni pamoja na # 1138 00:47:18,930 --> 00:47:22,190 stdio.h, na mimi naenda kufanya kuu int (utupu), na 1139 00:47:22,190 --> 00:47:24,680 tena, tutaweza kuja nyuma katika siku zijazo kama yale int ina maana 1140 00:47:24,680 --> 00:47:26,820 kuna na nini utupu maana huko. 1141 00:47:26,820 --> 00:47:28,770 Na sasa napenda kwenda mbele na kutekeleza mpango kwamba 1142 00:47:28,770 --> 00:47:31,170 kimsingi gani hii uongofu kwa ajili yetu. 1143 00:47:31,170 --> 00:47:36,830 >> Hivyo printf, hebu sema, joto katika Fahrenheit. 1144 00:47:36,830 --> 00:47:40,140 Na kisha napenda kwenda mbele na kupata thamani kutoka kwa mtumiaji. 1145 00:47:40,140 --> 00:47:43,120 Ni aina gani ya thamani lazima mimi kupata kutoka kwa mtumiaji kama nataka 1146 00:47:43,120 --> 00:47:45,620 yao kunipa joto katika Fahrenheit? 1147 00:47:45,620 --> 00:47:48,090 Yeah? 1148 00:47:48,090 --> 00:47:50,090 Gani unaweza kupendekeza? 1149 00:47:50,090 --> 00:47:50,410 Yeah. 1150 00:47:50,410 --> 00:47:51,960 Hivyo kuelea anahisi pretty busara. 1151 00:47:51,960 --> 00:47:53,950 Tuna, tena, tu chaguzi chache kwamba 1152 00:47:53,950 --> 00:47:55,310 tumeona hivi sasa. 1153 00:47:55,310 --> 00:48:00,100 Tuna vitu kama Char kuelea, mbili, int, muda mrefu, 1154 00:48:00,100 --> 00:48:01,150 bool, kamba. 1155 00:48:01,150 --> 00:48:03,510 Hivyo haya, kuelea anahisi pretty busara. 1156 00:48:03,510 --> 00:48:06,340 Tunaweza kutumia mara mbili, haki, kwa sababu kama kweli tunataka 1157 00:48:06,340 --> 00:48:07,580 kuwakilisha joto ya binadamu - 1158 00:48:07,580 --> 00:48:10,730 98.60000 - 1159 00:48:10,730 --> 00:48:12,990 tunaweza kutumia bits 64 kufanya hivyo, lakini anahisi kama 1160 00:48:12,990 --> 00:48:14,200 overkill kwa joto. 1161 00:48:14,200 --> 00:48:16,380 Basi hebu tu kwenda na kuelea. 1162 00:48:16,380 --> 00:48:18,100 Sasa mimi haja kutofautiana. 1163 00:48:18,100 --> 00:48:20,500 Tu kuweka mambo rahisi, mimi naenda kuiita f, lakini mimi 1164 00:48:20,500 --> 00:48:23,370 inaweza tu kama usahihi kuiita joto, 1165 00:48:23,370 --> 00:48:24,600 lakini aidha ni faini. 1166 00:48:24,600 --> 00:48:27,610 Hivyo kuelea f = GetFloat. 1167 00:48:27,610 --> 00:48:30,220 Haraka kama mimi sasa wameamua kutumia GetFloat, ingawa, mimi 1168 00:48:30,220 --> 00:48:33,340 haja ya kufanya marekebisho moja. 1169 00:48:33,340 --> 00:48:33,720 Yeah. 1170 00:48:33,720 --> 00:48:37,460 Hivyo tunahitaji # pamoja , vinginevyo ni mkusanyaji 1171 00:48:37,460 --> 00:48:39,000 kwenda yell saa yetu. 1172 00:48:39,000 --> 00:48:41,720 Sasa kwa kuwa nina kuelea, napenda kwenda mbele na kufanya 1173 00:48:41,720 --> 00:48:42,460 uongofu. 1174 00:48:42,460 --> 00:48:44,980 >> Hivyo kwanza, napenda pia kuingia katika tabia ya hapa 1175 00:48:44,980 --> 00:48:46,310 kutoa maoni yangu code. 1176 00:48:46,310 --> 00:48:49,820 Hivyo tena, maoni ni nukuu kwa binadamu kwamba ni 1177 00:48:49,820 --> 00:48:52,600 si sehemu ya mpango per se, lakini moja, husaidia 1178 00:48:52,600 --> 00:48:55,010 kuelewa nini alifanya asubuhi iliyofuata, au ujao 1179 00:48:55,010 --> 00:48:57,570 mwezi, inasaidia mafundisho wenzako kuelewa nini alifanya 1180 00:48:57,570 --> 00:48:59,230 au nini nia ya kufanya, hivyo ni 1181 00:48:59,230 --> 00:49:00,950 ujumla nzuri sana mazoezi. 1182 00:49:00,950 --> 00:49:02,940 Kila mistari michache ya kificho, na kuandika maoni ya 1183 00:49:02,940 --> 00:49:04,490 mwenyewe au mwenzake yako. 1184 00:49:04,490 --> 00:49:08,460 Hivyo hapa, mimi naenda kwa kusema, "Uliza mtumiaji kwa joto." 1185 00:49:08,460 --> 00:49:10,890 Je, si kuwa sentensi kamili, tu maneno mfupi. 1186 00:49:10,890 --> 00:49:14,270 Lakini wazo nyuma ya kutoa maoni katika C ni kwamba kila moja ya yako 1187 00:49:14,270 --> 00:49:17,980 maoni lazima kuwawezesha wewe - au, kusema, TF au mwenzake - 1188 00:49:17,980 --> 00:49:21,290 kwa skim mpango wako na kujua hasa nini anafanya, na si 1189 00:49:21,290 --> 00:49:24,650 sana kusoma kanuni, lakini kwa kusoma maoni, ambayo 1190 00:49:24,650 --> 00:49:26,220 lazima succinct na wazi. 1191 00:49:26,220 --> 00:49:29,030 Haki ya wote, hivyo sasa napenda kwenda mbele na kusema, "Convert 1192 00:49:29,030 --> 00:49:32,660 Fahrenheit kwa Celsius. "Kwa hiyo mimi nina kwenda mbele na kufanya, 1193 00:49:32,660 --> 00:49:34,340 hebu sema, kuelea c. 1194 00:49:34,340 --> 00:49:36,610 Tutaweka Celsius kama thamani floating uhakika. 1195 00:49:36,610 --> 00:49:37,630 >> Na napenda kuchukua kumchoma saa hii. 1196 00:49:37,630 --> 00:49:40,350 formula ni, tena, juu hapa. 1197 00:49:40,350 --> 00:49:45,510 Kama 5/9 mara F minus 32. 1198 00:49:45,510 --> 00:49:46,360 Basi hebu kufanya hili. 1199 00:49:46,360 --> 00:49:50,450 Hivyo 5 kugawanywa na 9, minus - 1200 00:49:50,450 --> 00:49:52,330 Whoops, mimi messed it up tayari. 1201 00:49:52,330 --> 00:49:53,070 Times. 1202 00:49:53,070 --> 00:49:56,550 Hivyo 5/9 mara F minus 32. 1203 00:49:56,550 --> 00:49:59,650 Hivyo F minus 32, semicolon. 1204 00:49:59,650 --> 00:50:02,000 Na sasa, chini hapa, mimi naenda kwa kwenda mbele 1205 00:50:02,000 --> 00:50:03,220 na kusema, magazeti matokeo. 1206 00:50:03,220 --> 00:50:05,160 Na sehemu hii ni rahisi. Printf. 1207 00:50:05,160 --> 00:50:07,980 Jinsi gani mimi kwenda kuhusu uchapishaji huu? 1208 00:50:07,980 --> 00:50:16,890 Naam, mimi naweza kusema "Hiyo idadi katika Celsius ni% f \ n", 1209 00:50:16,890 --> 00:50:18,060 tu kwa baadhi aesthetics. 1210 00:50:18,060 --> 00:50:20,450 Na kisha nini thamani mimi nataka kuziba katika hapa kama ya printf 1211 00:50:20,450 --> 00:50:21,360 pili hoja? 1212 00:50:21,360 --> 00:50:21,650 Sawa. 1213 00:50:21,650 --> 00:50:22,540 Hivyo tu c. 1214 00:50:22,540 --> 00:50:24,760 Hivyo tutaweza kuanza na hili na kisha kurudi tu 0. 1215 00:50:24,760 --> 00:50:25,960 Tena, ina chochote cha kufanya na math. 1216 00:50:25,960 --> 00:50:27,610 Ni tu ina maana yote ni sawa. 1217 00:50:27,610 --> 00:50:31,210 >> Sasa, hii ni sahihi, programu hii? 1218 00:50:31,210 --> 00:50:31,520 Wote haki. 1219 00:50:31,520 --> 00:50:33,630 Hivyo nimekuwa alifanya makosa ya baadhi ya. 1220 00:50:33,630 --> 00:50:35,980 Hata kama wewe hawana wazo nini ni programu, unaweza aina 1221 00:50:35,980 --> 00:50:37,120 ya infer nyuma ya shule ya daraja gani 1222 00:50:37,120 --> 00:50:38,740 makosa ya hapa inaweza kuwa. 1223 00:50:38,740 --> 00:50:40,050 Nini moja ya kwanza? 1224 00:50:40,050 --> 00:50:41,256 Watazamaji: [inaudible] 1225 00:50:41,256 --> 00:50:41,660 DAVID J. Malan: Yeah. 1226 00:50:41,660 --> 00:50:42,940 Hivyo sisi ni kukosa mabano. 1227 00:50:42,940 --> 00:50:45,420 Ilikuwa makusudi kwamba sikuwa mabano katika Akitoa 1228 00:50:45,420 --> 00:50:48,130 slide hapa, kwa sababu kuna kweli wazo hili la utaratibu 1229 00:50:48,130 --> 00:50:51,590 wa shughuli, au precedence, ambapo baadhi ya shughuli - 1230 00:50:51,590 --> 00:50:52,890 kuzidisha - 1231 00:50:52,890 --> 00:50:56,000 kuwa juu kisheria, kuwa juu precedence, kuliko mambo 1232 00:50:56,000 --> 00:50:58,050 Aidha kama au kutoa. 1233 00:50:58,050 --> 00:51:00,550 Hivyo tumefanya hii kwa miaka tu kufanya hasa wazi 1234 00:51:00,550 --> 00:51:02,840 nini operesheni ya hisabati kifanyike kwanza. 1235 00:51:02,840 --> 00:51:05,010 Basi, mimi lazima pengine mimic hasa hii. 1236 00:51:05,010 --> 00:51:08,990 Vinginevyo, kompyuta ni labda kwenda kujaribu kufanya 1237 00:51:08,990 --> 00:51:13,090 kitu kama mgawanyiko wa 5 na 9, kisha kuzidisha F, kisha toa 1238 00:51:13,090 --> 00:51:14,850 32 kutoka jambo zima. 1239 00:51:14,850 --> 00:51:16,480 Ambayo si, kwa kweli, ni nini tunataka kufanya. 1240 00:51:16,480 --> 00:51:17,340 Basi hebu parenthesize. 1241 00:51:17,340 --> 00:51:20,860 Hebu kuongeza mabano mabano yangu hapa, hapa. 1242 00:51:20,860 --> 00:51:22,670 Hebu kuweka hii hapa. 1243 00:51:22,670 --> 00:51:25,130 Hapa, mimi tu niliona mwingine kosa mimi kufanywa njiani. 1244 00:51:25,130 --> 00:51:25,680 Yeah? 1245 00:51:25,680 --> 00:51:26,930 Watazamaji: [inaudible] 1246 00:51:29,632 --> 00:51:30,130 >> DAVID J. Malan: Ah. 1247 00:51:30,130 --> 00:51:30,470 Nzuri. 1248 00:51:30,470 --> 00:51:32,400 Hivyo sisi kweli kuwa integer sawa 1249 00:51:32,400 --> 00:51:34,020 mgawanyiko suala mbele. 1250 00:51:34,020 --> 00:51:35,800 Mimi kusahihisha kwamba, hebu angalia nini dalili ni. 1251 00:51:35,800 --> 00:51:36,990 Lakini sisi ni kwenda na kusahihisha moja 1252 00:51:36,990 --> 00:51:37,680 nyingine makosa hapa. 1253 00:51:37,680 --> 00:51:38,015 Yeah? 1254 00:51:38,015 --> 00:51:39,540 Watazamaji: [inaudible] 1255 00:51:39,540 --> 00:51:40,070 DAVID J. Malan: Ndiyo. 1256 00:51:40,070 --> 00:51:43,130 Hivyo, stupid kosa mimi kufanywa, lakini ya muhimu. 1257 00:51:43,130 --> 00:51:45,870 kompyuta si kwenda tu kugeuka vipofu na basi 1258 00:51:45,870 --> 00:51:48,770 mimi kutumia mtaji F, wakati mimi kwa kweli alitangaza variable 1259 00:51:48,770 --> 00:51:51,360 kama f lowercase hapa, katika mstari wa 8. 1260 00:51:51,360 --> 00:51:54,470 Kwa hiyo mimi haja ya kurekebisha katika mtaji wa mstari 11 yangu, ambayo 1261 00:51:54,470 --> 00:51:56,820 wakati uliopita ilikuwa F mtaji kwa makosa. 1262 00:51:56,820 --> 00:51:57,610 Je kuhusu hapa? 1263 00:51:57,610 --> 00:51:59,980 Je hii kuwa lowercase vile vile? 1264 00:51:59,980 --> 00:52:02,260 Ni lazima, lakini hiyo ni bahati mbaya. 1265 00:52:02,260 --> 00:52:05,070 Hiyo f% hauhusiani na kutofautiana. 1266 00:52:05,070 --> 00:52:07,980 Hivyo tu kuwa super wazi hapa, napenda kwenda mbele na 1267 00:52:07,980 --> 00:52:10,710 rename hii, kwa ufupi, "joto." Hebu rename 1268 00:52:10,710 --> 00:52:15,050 hii "joto." Basi mimi si rename hii. 1269 00:52:15,050 --> 00:52:18,180 Kwa sababu, tena,% f kimataifa maana yake, "floating kumweka thamani." 1270 00:52:18,180 --> 00:52:19,950 Ana kitu cha kufanya na variable yangu. 1271 00:52:19,950 --> 00:52:23,080 Lakini "joto" kila mahali ni kidogo tu wordy, 1272 00:52:23,080 --> 00:52:25,370 hivyo mimi nina kwenda nyuma lowercase yangu ya "f". 1273 00:52:25,370 --> 00:52:27,890 >> Sasa, basi mimi kwenda mbele chini ya dirisha yangu hapa. 1274 00:52:27,890 --> 00:52:29,190 Matokeo f2c - 1275 00:52:29,190 --> 00:52:31,200 ambayo ilikuwa, tena, jina holela mimi 1276 00:52:31,200 --> 00:52:32,590 akawapa faili hii. 1277 00:52:32,590 --> 00:52:33,690 Inaonekana kuwa compiled. 1278 00:52:33,690 --> 00:52:35,080 Hebu kukimbia f2c. 1279 00:52:35,080 --> 00:52:35,780 Kuingia. 1280 00:52:35,780 --> 00:52:37,786 Joto katika Fahrenheit - wacha kufanya moja rahisi. 1281 00:52:37,786 --> 00:52:39,370 32. 1282 00:52:39,370 --> 00:52:40,910 OK, kusahihisha. 1283 00:52:40,910 --> 00:52:45,910 Lakini, ikiwa mimi sasa kufanya 212 kwa kiwango - 1284 00:52:45,910 --> 00:52:46,630 damn. 1285 00:52:46,630 --> 00:52:47,030 Wote haki. 1286 00:52:47,030 --> 00:52:50,780 Hiyo, ni wazi si sahihi, kama TF yako anajaribu 1287 00:52:50,780 --> 00:52:51,800 angalau wawili maadili. 1288 00:52:51,800 --> 00:52:53,340 Basi nini tatizo hapa? 1289 00:52:53,340 --> 00:52:55,970 Naam, tayari kuweka kidole yako juu ya nini suala hilo ni. 1290 00:52:55,970 --> 00:52:57,600 Lakini kwa nini ni kwamba kesi? 1291 00:52:57,600 --> 00:53:00,630 Hadi hapa, wakati mimi nina kufanya math ya 5 kugawanywa na 9. 1292 00:53:00,630 --> 00:53:02,190 Hivyo conceptually, hiyo ni kikamilifu sahihi. 1293 00:53:02,190 --> 00:53:03,690 Kabisa sambamba na formula. 1294 00:53:03,690 --> 00:53:05,940 Lakini kompyuta tu kufanya just nini wewe 1295 00:53:05,940 --> 00:53:06,760 kuwaambia cha kufanya. 1296 00:53:06,760 --> 00:53:08,940 Na nini tuko ufanisi kuiambia kompyuta hapa ni 1297 00:53:08,940 --> 00:53:12,320 kugawanya 5 integer na 9 integer 1298 00:53:12,320 --> 00:53:13,670 na nipe matokeo. 1299 00:53:13,670 --> 00:53:16,230 Tatizo ni, ingawa, wakati wa kufanya mgawanyiko kwa kutumia data 1300 00:53:16,230 --> 00:53:20,220 aina, pato ni sawa data aina kama pembejeo. 1301 00:53:20,220 --> 00:53:23,670 Na hivyo kama pembejeo mbili ni wawili ints, pato ni kwenda 1302 00:53:23,670 --> 00:53:25,110 kuwa int. 1303 00:53:25,110 --> 00:53:28,770 Na hivyo 5 kugawanywa na 9 ni uhakika kitu. 1304 00:53:28,770 --> 00:53:32,320 Lakini nini integer karibu kwa uhakika kitu? 1305 00:53:32,320 --> 00:53:33,630 Hivyo, ni kweli 0. 1306 00:53:33,630 --> 00:53:36,620 Hivyo kama sisi kujadiliwa siku ya Jumatatu, kila kitu baada ya decimal 1307 00:53:36,620 --> 00:53:37,940 uhakika anapata truncated. 1308 00:53:37,940 --> 00:53:39,495 Ni tu anapata kutupwa mbali. 1309 00:53:39,495 --> 00:53:42,760 Hivyo hili ni kosa kamili, kwa sababu mimi ili kama vile tu 1310 00:53:42,760 --> 00:53:44,700 kuzidisha kila kitu kwa 0 hapa. 1311 00:53:44,700 --> 00:53:46,550 >> Sasa, siwezi kurekebisha hii katika michache ya njia. 1312 00:53:46,550 --> 00:53:48,080 Mimi naweza kufanya hili. 1313 00:53:48,080 --> 00:53:50,490 5.0 kugawanywa na 9.0. 1314 00:53:50,490 --> 00:53:52,110 Kitaalam, sijui hata haja ya kufanya hivyo. 1315 00:53:52,110 --> 00:53:55,780 Ni gani inatosha tu kufanya moja ya idadi kuelea - 1316 00:53:55,780 --> 00:53:58,290 au mara mbili - kwa kuweka uhakika decimal hapa. 1317 00:53:58,290 --> 00:54:01,740 Kwa sababu kile kinachotokea sasa ni wakati kugawanya integer na 1318 00:54:01,740 --> 00:54:04,670 kuelea, au mara mbili, kompyuta kinaendelea kwa kutambua 1319 00:54:04,670 --> 00:54:06,830 oh, mmoja wa wale ni sahihi zaidi. 1320 00:54:06,830 --> 00:54:09,420 Hebu apotee upande wa kutoa zaidi kuliko usahihi 1321 00:54:09,420 --> 00:54:10,310 wewe lengo. 1322 00:54:10,310 --> 00:54:12,700 Hivyo itakuwa kubadilisha matokeo - 1323 00:54:12,700 --> 00:54:16,240 itakuwa kurudi matokeo kama thamani floating kumweka pia. 1324 00:54:16,240 --> 00:54:17,330 Hivyo kwamba ingekuwa kazi. 1325 00:54:17,330 --> 00:54:18,060 Hii ingekuwa kazi. 1326 00:54:18,060 --> 00:54:20,010 Na kuna mtu mwingine utaratibu kwamba tutaweza kuona katika 1327 00:54:20,010 --> 00:54:21,390 zaidi undani wiki ijayo. 1328 00:54:21,390 --> 00:54:24,690 Unaweza kweli, kama programu, kuiambia kompyuta 1329 00:54:24,690 --> 00:54:27,930 kwa kweli kutibu data aina moja kama 1330 00:54:27,930 --> 00:54:29,260 ingawa walikuwa mwingine. 1331 00:54:29,260 --> 00:54:30,990 >> Kwa hiyo mimi nilikuwa kwa kweli kufanya kazi hii. 1332 00:54:30,990 --> 00:54:35,280 Katika mabano, siwezi kusema kitu kama (kuelea), wazi 1333 00:54:35,280 --> 00:54:36,350 Paren, karibu Paren. 1334 00:54:36,350 --> 00:54:39,050 Na hii ni nini inayoitwa "akitoa." Tena, zaidi 1335 00:54:39,050 --> 00:54:39,940 juu ya hili wiki ijayo. 1336 00:54:39,940 --> 00:54:42,280 Lakini hii ni njia tu ya programu ya kuwaambia 1337 00:54:42,280 --> 00:54:45,910 kompyuta, yeah Mimi najua 9 ni integer au mrefu. 1338 00:54:45,910 --> 00:54:47,700 Najua ni si floating kumweka thamani. 1339 00:54:47,700 --> 00:54:49,420 Lakini kutibu kama vile anyway. 1340 00:54:49,420 --> 00:54:52,000 Hivyo kuwafukuza data aina maana ya kubadilisha 1341 00:54:52,000 --> 00:54:53,310 kutoka moja hadi nyingine. 1342 00:54:53,310 --> 00:54:55,790 Kwa kweli, huu ni kidogo tu ugly, hivyo napenda kupendekeza sisi kwenda 1343 00:54:55,790 --> 00:54:58,830 nyuma kwa maoni ya awali ya tu kuwabadili 1344 00:54:58,830 --> 00:55:00,770 mambo haya kwa yaliyo maadili uhakika manually. 1345 00:55:00,770 --> 00:55:02,890 Kwa sababu sasa ni kama tu super wazi nini kinaendelea, na 1346 00:55:02,890 --> 00:55:04,280 si wote kwamba bughudha. 1347 00:55:04,280 --> 00:55:06,710 >> Basi hebu sasa kurudi nyuma katika terminal dirisha yangu. 1348 00:55:06,710 --> 00:55:07,990 Matokeo f2c. 1349 00:55:07,990 --> 00:55:09,430 Hebu kwenda mbele na kukimbia hii. 1350 00:55:09,430 --> 00:55:12,340 Na, kama kando, wewe kupata kuchoka kuandika amri hizi 1351 00:55:12,340 --> 00:55:14,910 tena na tena, kutambua kompyuta kwamba, kama Linux hapa, 1352 00:55:14,910 --> 00:55:16,010 zinaelekea kuwa pretty smart. 1353 00:55:16,010 --> 00:55:18,890 Na kama mimi hit Up, tunaweza kwenda kwa historia yangu yote ya 1354 00:55:18,890 --> 00:55:20,380 amri, na Up Down. 1355 00:55:20,380 --> 00:55:23,840 Hivyo katika kesi hii hapa, mimi unaweza tu kwenda Hadi kukimbia kufanya f2c. 1356 00:55:23,840 --> 00:55:25,830 Mimi nina kuwa yelled saa, kwa sababu mimi tu walifanya pili iliyopita. 1357 00:55:25,830 --> 00:55:27,030 Ni tayari hadi sasa. 1358 00:55:27,030 --> 00:55:30,720 Hivyo sasa siwezi kukimbia f2c tena. 1359 00:55:30,720 --> 00:55:33,260 Hebu jaribu 32 Fahrenheit. 1360 00:55:33,260 --> 00:55:36,720 Sasa hebu jaribu 212 Fahrenheit. 1361 00:55:36,720 --> 00:55:37,250 >> Phew. 1362 00:55:37,250 --> 00:55:38,250 Inaonekana kazi. 1363 00:55:38,250 --> 00:55:41,760 Sasa, hii ni nzuri, lakini anahisi kidogo kiholela kwamba 1364 00:55:41,760 --> 00:55:44,890 Mimi nina kuonyesha namba sita baada ya pointi decimal. 1365 00:55:44,890 --> 00:55:45,070 Haki? 1366 00:55:45,070 --> 00:55:47,830 Kama wewe ni mtu wa hali ya hewa kwenye TV, wewe ni aina ya doofus 1367 00:55:47,830 --> 00:55:49,150 kama wewe ni kusoma kwa joto 1368 00:55:49,150 --> 00:55:50,070 hii shahada ya usahihi. 1369 00:55:50,070 --> 00:55:51,270 Basi hebu kurahisisha hii. 1370 00:55:51,270 --> 00:55:53,880 Basi hebu kweli kwenda juu hapa, kwa printf yangu. 1371 00:55:53,880 --> 00:55:55,490 Na yeah, nataka kuelea. 1372 00:55:55,490 --> 00:55:57,570 Lakini nataka sasa kutaja usahihi. 1373 00:55:57,570 --> 00:55:59,070 Na mimi nina kwenda kuwa succinct kidogo. 1374 00:55:59,070 --> 00:56:03,090 Mimi nina kwenda kusema, nipe moja ya uhakika baada ya mahali decimal. 1375 00:56:03,090 --> 00:56:07,590 Hivyo badala ya kusema% f, mimi nina kwenda kusema% 0.1 f. 1376 00:56:07,590 --> 00:56:09,760 Na hii ina maana tu nipe nafasi moja 1377 00:56:09,760 --> 00:56:11,410 baada ya uhakika decimal. 1378 00:56:11,410 --> 00:56:11,700 Wote haki. 1379 00:56:11,700 --> 00:56:12,570 Hebu jaribu hii tena. 1380 00:56:12,570 --> 00:56:15,590 Hebu kuendesha upya baada ya kuandaa. 1381 00:56:15,590 --> 00:56:18,160 Na sasa ninapoandika katika 32, na mimi kupata nyuma 1382 00:56:18,160 --> 00:56:19,310 zaidi succinct thamani. 1383 00:56:19,310 --> 00:56:22,480 Na siwezi aina katika, sasa, 212, na kupata nyuma succinct zaidi 1384 00:56:22,480 --> 00:56:23,260 thamani pia. 1385 00:56:23,260 --> 00:56:25,190 Na kuna mambo mengine unaweza kufanya na printf. 1386 00:56:25,190 --> 00:56:27,950 Unaweza kweli bayana jinsi pana idadi lazima. 1387 00:56:27,950 --> 00:56:30,900 Kama unataka kuwa na padding juu yake, hivyo unaweza haki-align au 1388 00:56:30,900 --> 00:56:32,360 kushoto-align wote wa namba yako au 1389 00:56:32,360 --> 00:56:33,400 kujaribu mambo katikati. 1390 00:56:33,400 --> 00:56:35,340 Hivyo kutambua kuna kidogo tricks unaweza kufanya huko. 1391 00:56:35,340 --> 00:56:38,420 Lakini wao tu chemsha chini codes format, 1392 00:56:38,420 --> 00:56:39,600 kama tuna huko. 1393 00:56:39,600 --> 00:56:41,090 >> Hivyo katika suala hili la precedence. 1394 00:56:41,090 --> 00:56:43,820 Hii ndiyo meza boring sana kupitia methodically. 1395 00:56:43,820 --> 00:56:46,780 Lakini kutambua kwamba waandishi wa C wamekuja na 1396 00:56:46,780 --> 00:56:50,190 sheria kwamba kutaja waendeshaji kuwa juu 1397 00:56:50,190 --> 00:56:53,680 precedence, unaofunga zaidi nguvu, kuliko wengine. 1398 00:56:53,680 --> 00:56:55,890 Hivyo wakati katika shule ya daraja, sisi ujumla alijua kuwa ilikuwa ni 1399 00:56:55,890 --> 00:56:58,930 kuzidisha na kugawanya, kisha kujumlisha na kutoa, 1400 00:56:58,930 --> 00:56:59,950 kisha baadhi ya mambo mengine. 1401 00:56:59,950 --> 00:57:01,720 Katika ulimwengu wa programu, kuna mengi 1402 00:57:01,720 --> 00:57:03,360 tena orodha ya mambo. 1403 00:57:03,360 --> 00:57:05,150 Na hii si kitu yenye thamani ya kukariri sasa. 1404 00:57:05,150 --> 00:57:07,310 Utasikia kupata acclimated hiyo kabla ya muda mrefu. 1405 00:57:07,310 --> 00:57:10,690 Lakini tu kama katika shule ya daraja, mabano ujumla kutatua 1406 00:57:10,690 --> 00:57:12,990 masuala ya precedence, kwa kufanya super wazi kwa 1407 00:57:12,990 --> 00:57:15,620 kompyuta na binadamu sawa yale yaliyokusudiwa. 1408 00:57:15,620 --> 00:57:17,770 Hivyo kufikiria hili kidogo tu kudanganya karatasi huko. 1409 00:57:17,770 --> 00:57:21,690 Lakini wengi wa wale maelezo hatutaweza kupata kwa wakati fulani. 1410 00:57:21,690 --> 00:57:21,900 >> Wote haki. 1411 00:57:21,900 --> 00:57:24,120 Sasa, hebu kujenga na kuondokana na kidogo hizi silly 1412 00:57:24,120 --> 00:57:25,460 hisabati mifano. 1413 00:57:25,460 --> 00:57:27,500 Bado kutumia misingi sawa, lakini kuanza 1414 00:57:27,500 --> 00:57:29,960 akielezea wenyewe zaidi kidogo kama Scratch. 1415 00:57:29,960 --> 00:57:31,660 Hivyo katika Scratch, tulikuwa na maneno hayo Boolean. 1416 00:57:31,660 --> 00:57:34,890 Na katika Kiingereza, kujieleza Boolean ni nini? 1417 00:57:34,890 --> 00:57:35,580 Kweli au uongo. 1418 00:57:35,580 --> 00:57:38,300 Ni kitu ambacho kutathmini kwa kweli au uongo. 1419 00:57:38,300 --> 00:57:39,060 1 au 0. 1420 00:57:39,060 --> 00:57:39,870 Juu au mbali. 1421 00:57:39,870 --> 00:57:41,000 Chochote unataka simu yake. 1422 00:57:41,000 --> 00:57:43,210 Sasa katika Scratch, vipande puzzle inaonekana kama hii. 1423 00:57:43,210 --> 00:57:45,850 Na kwamba ni mchanganyiko, juu ya chini huko, ya tatu 1424 00:57:45,850 --> 00:57:47,980 puzzle vipande vipande. 1425 00:57:47,980 --> 00:57:48,980 Muunganiko mmoja - 1426 00:57:48,980 --> 00:57:51,710 kitu ambayo ina tupu na tupu. 1427 00:57:51,710 --> 00:57:53,970 Na kisha mbili Boolean maneno ndani yake. 1428 00:57:53,970 --> 00:57:56,460 Hivyo unaweza kiota Boolean misemo kupata zaidi 1429 00:57:56,460 --> 00:57:59,360 ngumu misemo Boolean. 1430 00:57:59,360 --> 00:58:03,930 Kwa mfano, kama ni Jumamosi, na ni nzuri 1431 00:58:03,930 --> 00:58:06,180 hali ya hewa, kisha kwenda nje. 1432 00:58:06,180 --> 00:58:07,500 Au kitu kama hicho holela. 1433 00:58:07,500 --> 00:58:10,090 Hivyo unaweza kujiunga misemo Boolean kuja na 1434 00:58:10,090 --> 00:58:12,780 kubwa thamani ukweli, ambao jibu ni msingi 1435 00:58:12,780 --> 00:58:13,800 juu ya wale madogo. 1436 00:58:13,800 --> 00:58:15,770 >> Sasa, katika C, nashiriki, ramani hii ni 1437 00:58:15,770 --> 00:58:16,720 kweli pretty rahisi. 1438 00:58:16,720 --> 00:58:18,820 Mabano kusaidia kufanya mambo wazi hapa. 1439 00:58:18,820 --> 00:58:21,700 && Ni nini maana ya "na." Basi hiyo ni jinsi 1440 00:58:21,700 --> 00:58:24,700 tunakwenda kubadili vitalu wale kutoka kwa Scratch C. 1441 00:58:24,700 --> 00:58:27,590 Na kwa hali tuliona katika Scratch, kwa upande wa kushoto 1442 00:58:27,590 --> 00:58:31,150 upande huko, siwezi stack yao vile vile katika C. Kama x ni chini 1443 00:58:31,150 --> 00:58:32,970 kuliko y, kisha kufanya hili. 1444 00:58:32,970 --> 00:58:35,100 Mwingine kama x ni mkubwa kuliko y, kisha kufanya hili. 1445 00:58:35,100 --> 00:58:38,030 Mwingine kimantiki ni lazima kuwa sawa, hivyo kusema 1446 00:58:38,030 --> 00:58:39,140 kwamba wao ni sawa. 1447 00:58:39,140 --> 00:58:41,210 Basi, tunaweza sasa kuanza kujenga mambo haya juu. 1448 00:58:41,210 --> 00:58:42,170 >> Basi hebu kufanya mfano. 1449 00:58:42,170 --> 00:58:45,550 Hebu kufungua faili hilo kwenye tovuti shaka kwamba 1450 00:58:45,550 --> 00:58:47,270 Mimi aliandika mapema. 1451 00:58:47,270 --> 00:58:50,540 Hiyo inaitwa nonswitch.c. 1452 00:58:50,540 --> 00:58:52,270 Na tutaweza kuona nini katika muda tu. 1453 00:58:52,270 --> 00:58:54,770 Hivyo katika faili hii - nonswitch.c-- 1454 00:58:54,770 --> 00:58:56,830 kwanza kutambua kwamba kuna rundo zima la 1455 00:58:56,830 --> 00:58:58,460 maoni juu. 1456 00:58:58,460 --> 00:59:00,110 Hiyo tu kueleza jina la faili, ni nini 1457 00:59:00,110 --> 00:59:01,260 gani, na kadhalika. 1458 00:59:01,260 --> 00:59:04,390 Na inaonekana inaonyesha matumizi ya Boolean NA-ing - 1459 00:59:04,390 --> 00:59:06,220 conjoining misemo miwili. 1460 00:59:06,220 --> 00:59:07,670 >> Basi hebu angalia jinsi gani mpango huu unavyofanya kazi. 1461 00:59:07,670 --> 00:59:10,840 Mimi ni pamoja wangu files mbili, cs50.h na stdio.h. 1462 00:59:10,840 --> 00:59:13,180 Kama mimi kitabu chini, sasa, kwa mpango, ni muda mrefu kidogo 1463 00:59:13,180 --> 00:59:15,730 kuliko tumekuwa iliyoandikwa kabla, lakini pretty someka. 1464 00:59:15,730 --> 00:59:18,360 Basi, mimi kwanza magazeti kwa mtumiaji, juu ya mstari 18, 1465 00:59:18,360 --> 00:59:20,460 "Nipe integer kati ya 1 na 10." Hivyo 1466 00:59:20,460 --> 00:59:21,530 hiyo ni haki huko. 1467 00:59:21,530 --> 00:59:23,410 Sasa mimi kupata integer. 1468 00:59:23,410 --> 00:59:25,380 Lakini kutambua kwamba GetInt - pretty rahisi. 1469 00:59:25,380 --> 00:59:26,510 Ni tu kwenda kupata int. 1470 00:59:26,510 --> 00:59:28,830 Ni kwenda kuhakikisha kwamba hana kupata int na si 1471 00:59:28,830 --> 00:59:30,060 kamba au kamba ya kuelea. 1472 00:59:30,060 --> 00:59:32,390 Lakini si kwenda kufanya aina yoyote ya kuangalia mipaka. 1473 00:59:32,390 --> 00:59:34,750 Ni si kwenda kuchuja idadi kuwa kati ya 1474 00:59:34,750 --> 00:59:35,630 fulani mbalimbali. 1475 00:59:35,630 --> 00:59:37,730 Hivyo tuna kutekeleza kwamba sisi wenyewe. 1476 00:59:37,730 --> 00:59:40,680 Hivyo kama katika Scratch, ambapo mimi naweza kufanya kushirikiana ya 1477 00:59:40,680 --> 00:59:43,560 mbili misemo, siwezi kufanya hivyo katika C kama ifuatavyo. 1478 00:59:43,560 --> 00:59:48,660 Kama n, ni mkubwa kuliko au sawa na 1, na n ni chini ya na 1479 00:59:48,660 --> 00:59:52,220 au sawa na 3, mimi naenda sana amri kiholela kwamba 1480 00:59:52,220 --> 00:59:53,830 idadi kuwa idadi ndogo. 1481 00:59:53,830 --> 00:59:56,730 Tu kwa ajili ya taarifa hiyo. 1482 00:59:56,730 --> 01:00:00,210 Mwingine ikiwa n ni kati ya 4 na 6, magazeti "Wewe ilichukua kati 1483 01:00:00,210 --> 01:00:03,440 idadi. "Else ikiwa n ni kati ya 7 na 10, magazeti" Wewe ilichukua 1484 01:00:03,440 --> 01:00:06,390 kubwa idadi. "Else magazeti" Wewe kuchukua idadi batili. " 1485 01:00:06,390 --> 01:00:07,900 Kwa sababu mantiki, kwamba ifuatavyo ikiwa tumekuwa 1486 01:00:07,900 --> 01:00:09,230 nimechoka mbalimbali wetu. 1487 01:00:09,230 --> 01:00:12,400 >> Hivyo kutambua hii si kabisa jinsi sisi kuandika zaidi au 1488 01:00:12,400 --> 01:00:15,000 sawa na katika darasa math. 1489 01:00:15,000 --> 01:00:15,160 Haki? 1490 01:00:15,160 --> 01:00:17,430 Wewe kawaida kuteka ni kama hii, na mstari chini yake. 1491 01:00:17,430 --> 01:00:19,250 Lakini hakuna ufunguo vile kwenye keyboard yangu. 1492 01:00:19,250 --> 01:00:22,390 Hivyo alama katika C kwa kueleza zaidi au 1493 01:00:22,390 --> 01:00:25,770 sawa na ni herufi mbili, na ishara kwa chini ya 1494 01:00:25,770 --> 01:00:29,100 au sawa na ni herufi mbili vilevile. 1495 01:00:29,100 --> 01:00:29,330 Wote haki. 1496 01:00:29,330 --> 01:00:31,910 Hivyo kama mimi kukimbia katika mpango huu, pengine unaweza nadhani nini ni 1497 01:00:31,910 --> 01:00:32,650 kwenda kufanya. 1498 01:00:32,650 --> 01:00:36,180 Kama mimi kwenda mbele na kufanya nonswitch, Ingiza. 1499 01:00:36,180 --> 01:00:38,130 Na kisha kukimbia nonswitch. 1500 01:00:38,130 --> 01:00:39,530 Nipe namba kati ya 1 na 10. 1501 01:00:39,530 --> 01:00:40,870 Mimi naenda kuwapa 11. 1502 01:00:40,870 --> 01:00:42,280 Mimi ilichukua idadi batili. 1503 01:00:42,280 --> 01:00:44,090 Hebu jaribu namba 3. 1504 01:00:44,090 --> 01:00:45,990 Mimi ilichukua idadi ndogo. 1505 01:00:45,990 --> 01:00:48,360 Hivyo haki moja kwa moja huko. 1506 01:00:48,360 --> 01:00:52,230 >> Nini kama nataka kubadili tabia ya mpango huu na 1507 01:00:52,230 --> 01:00:54,250 kufanya kitu tofauti kidogo badala yake? 1508 01:00:54,250 --> 01:00:57,620 Hebu kwenda mbele na kusema hii. 1509 01:00:57,620 --> 01:00:59,480 Hebu kujikwamua yote hii. 1510 01:00:59,480 --> 01:01:03,780 Na napenda kusema kama (n == 42). 1511 01:01:03,780 --> 01:01:08,730 Na kisha mimi nina kwenda mbele na kusema magazeti "Wewe ilichukua 1512 01:01:08,730 --> 01:01:16,340 haki jibu. "Else tunakwenda kwenda mbele na kusema, 1513 01:01:16,340 --> 01:01:18,460 printf ("Wewe ilichukua 1514 01:01:18,460 --> 01:01:21,170 dhulumu jibu ");. Sawa. 1515 01:01:21,170 --> 01:01:22,040 Kwa sababu tu. 1516 01:01:22,040 --> 01:01:23,890 >> Sasa, pointi chache tunaweza kufanya hapa. 1517 01:01:23,890 --> 01:01:26,570 Moja, sikuweza aina ishara kwamba unaweza kudhani ni 1518 01:01:26,570 --> 01:01:27,390 nzuri zaidi. 1519 01:01:27,390 --> 01:01:30,110 Wakati nataka kuangalia usawa, zinageuka huna matumizi 1520 01:01:30,110 --> 01:01:30,910 sawa ishara. 1521 01:01:30,910 --> 01:01:34,000 Wewe badala yake kutumia sawa sawa ishara. 1522 01:01:34,000 --> 01:01:36,440 Na kwa nini kinaweza kuwa kuwa, tu intuitively? 1523 01:01:36,440 --> 01:01:37,030 Yeah. 1524 01:01:37,030 --> 01:01:39,330 Watazamaji: [inaudible] 1525 01:01:39,330 --> 01:01:39,615 DAVID J. Malan: Sahihi. 1526 01:01:39,615 --> 01:01:41,630 ishara sawa tayari kutumika kwa ajili ya zoezi. 1527 01:01:41,630 --> 01:01:43,020 Mtu hawakuwa kweli nadhani hii kupitia. 1528 01:01:43,020 --> 01:01:45,820 Na hivyo sasa, linapokuja kupima usawa, tuna 1529 01:01:45,820 --> 01:01:48,850 kuwa wazi zaidi, na kusema sawa sawa. 1530 01:01:48,850 --> 01:01:52,110 makosa ya kawaida sana ni kufanya hili. 1531 01:01:52,110 --> 01:01:54,800 Na, kama katika ofisi ya masaa au wakati mwingine wiki ijayo au katika 1532 01:01:54,800 --> 01:01:58,340 ijayo wiki mbili wewe kufanya kitu kama hiki na kisha 1533 01:01:58,340 --> 01:02:00,920 mapambano na ni kwa ajili ya 10, dakika 20 kujaribu kufikiri 1534 01:02:00,920 --> 01:02:03,330 nini mdudu damn ni, kutambua kwamba wewe ni mmoja wa wale 1535 01:02:03,330 --> 01:02:04,470 watu ambao alifanya hii kosa. 1536 01:02:04,470 --> 01:02:06,030 Hivyo, super rahisi kutengeneza. 1537 01:02:06,030 --> 01:02:08,240 Lakini lengo sasa ni kuizuia hii kosa. 1538 01:02:08,240 --> 01:02:11,840 Hii inaweza kutathmini, kwa sababu ni nini kweli hii kusema? 1539 01:02:11,840 --> 01:02:15,010 Kama n anapata 42. 1540 01:02:15,010 --> 01:02:18,250 Hivyo watu kitenzi kutumia, maneno, ya kueleza 1541 01:02:18,250 --> 01:02:21,800 dhana ya zoezi ni "anapata." Hivyo kama n anapata 42. 1542 01:02:21,800 --> 01:02:24,060 Hivyo kwamba maana hawawajui 42 kwa n. 1543 01:02:24,060 --> 01:02:26,250 Sasa nina kujieleza Boolean katika mabano, 1544 01:02:26,250 --> 01:02:30,230 ndani ya hali hii, ambayo ni ya thamani 42. 1545 01:02:30,230 --> 01:02:30,390 Haki? 1546 01:02:30,390 --> 01:02:32,690 Kwa sababu kama wewe ni kutoka nje kutathmini ndani, jumla ya 1547 01:02:32,690 --> 01:02:34,100 jibu, sasa, ni 42. 1548 01:02:34,100 --> 01:02:37,360 >> Hivyo kama mimi aliuliza swali, "kama (42)," ni nini 1549 01:02:37,360 --> 01:02:38,410 kwamba kweli kusema? 1550 01:02:38,410 --> 01:02:40,990 Naam, Boolean misemo inaweza tu kuwa ni kweli au uongo. 1551 01:02:40,990 --> 01:02:42,010 1 au 0. 1552 01:02:42,010 --> 01:02:43,010 Juu au mbali. 1553 01:02:43,010 --> 01:02:45,240 Hivyo sisi tunaonekana kuwa na kesi kona hapa, ambapo wote wa 1554 01:02:45,240 --> 01:02:50,060 ghafla, mimi kusema "kama (42)". Hiyo siyo thamani Boolean. 1555 01:02:50,060 --> 01:02:54,500 Hivyo kile kompyuta kufanya, ingawa, ni kimsingi equates 1556 01:02:54,500 --> 01:02:58,620 chochote ambacho si 0 ni kufasiriwa kuwa ni kweli. 1557 01:02:58,620 --> 01:02:59,340 1. 1558 01:02:59,340 --> 01:02:59,690 On. 1559 01:02:59,690 --> 01:03:01,510 Wao ni wote functionally sawa. 1560 01:03:01,510 --> 01:03:05,070 Tu thamani 0, au Keyword uongo, kama tutaweza 1561 01:03:05,070 --> 01:03:07,860 hatimaye kuona, ni kweli uongo. 1562 01:03:07,860 --> 01:03:15,040 Hivyo "kama (42)" ingekuwa kweli kuwa kweli, kwa sababu ni zisizo sifuri. 1563 01:03:15,040 --> 01:03:18,620 Hivyo kwa kuwa sahihi zaidi hapa, thamani Boolean ni kweli si hivyo 1564 01:03:18,620 --> 01:03:20,680 mengi ya kweli au uongo, lakini kwa hili 1565 01:03:20,680 --> 01:03:24,650 kesi, ikiwa ni 0 au yasiyo ya sifuri. 1566 01:03:24,650 --> 01:03:26,330 Hivyo uongo au si ya uongo. 1567 01:03:26,330 --> 01:03:28,640 Na kwamba inaruhusu sisi imewazunguka wote zaidi 1568 01:03:28,640 --> 01:03:30,980 uwezekano katika kujieleza parenthetical. 1569 01:03:30,980 --> 01:03:33,840 Hivyo tunahitaji, milele hivyo kwa uangalifu, kusema hii - 1570 01:03:33,840 --> 01:03:35,620 kama (n == 42). 1571 01:03:35,620 --> 01:03:39,100 Ni kwa sababu tu tunahitaji kutaja mtihani wa usawa, 1572 01:03:39,100 --> 01:03:40,930 si zoezi la thamani. 1573 01:03:40,930 --> 01:03:42,830 >> Kile kingine ni thamani akibainisha hapa? 1574 01:03:42,830 --> 01:03:46,030 Hizi braces curly ni kweli si lazima. 1575 01:03:46,030 --> 01:03:48,650 Nimekuwa kufanya nao tu kuwa NIT-picky hapa. 1576 01:03:48,650 --> 01:03:51,350 Lakini wakati una hali ya kuwa tu ana mstari mmoja wa 1577 01:03:51,350 --> 01:03:55,100 code, kama urahisi, programmers hawana haja ya kutumia 1578 01:03:55,100 --> 01:03:56,030 braces curly. 1579 01:03:56,030 --> 01:03:59,370 Inatosha tu Indent, kwa sababu za estetiska, na 1580 01:03:59,370 --> 01:04:01,050 kisha kuandika wako mstari wa kificho. 1581 01:04:01,050 --> 01:04:04,160 Tu wakati unataka kuandika mistari miwili ya code - kwa 1582 01:04:04,160 --> 01:04:08,230 mfano, mwingine printf ("Bye!"). Kama unataka kufanya 1583 01:04:08,230 --> 01:04:09,540 kwamba, hii ni kuvunjwa. 1584 01:04:09,540 --> 01:04:11,700 Unaweza Indent unataka wote, lakini ukweli kwamba una 1585 01:04:11,700 --> 01:04:14,600 typed mistari miwili ya kificho bila kutumia braces curly 1586 01:04:14,600 --> 01:04:16,860 ina maana kwamba programu hii itakuwa si kukimbia usahihi au nguvu 1587 01:04:16,860 --> 01:04:18,530 hata kukusanya usahihi. 1588 01:04:18,530 --> 01:04:21,040 Hivyo kwa sasa, kwa kuwa waaminifu, nadhani tabia bora ni tu 1589 01:04:21,040 --> 01:04:24,460 kutumia braces curly, na utapata kwamba wao kufanya 1590 01:04:24,460 --> 01:04:25,750 super wazi nini kinaendelea. 1591 01:04:25,750 --> 01:04:29,410 >> Pia, kama kando - hasa kama wewe ni miongoni mwa wale ambao wanatumia 1592 01:04:29,410 --> 01:04:31,700 vitabu ilipendekeza au rasilimali online - 1593 01:04:31,700 --> 01:04:33,480 kutambua kwamba kuna wazo hili la mtindo katika 1594 01:04:33,480 --> 01:04:34,130 programu. 1595 01:04:34,130 --> 01:04:37,280 Na baadhi ya watu kweli wanapendelea kuweka brace curly 1596 01:04:37,280 --> 01:04:38,720 juu hapa kwenye mstari. 1597 01:04:38,720 --> 01:04:41,520 Baadhi ya watu wanapendelea kufanya mambo ujinga, 1598 01:04:41,520 --> 01:04:43,830 kama kuziweka hapa. 1599 01:04:43,830 --> 01:04:45,140 Hakuna jibu sahihi linapokuja 1600 01:04:45,140 --> 01:04:46,710 style, lakini hii ni sahihi. 1601 01:04:46,710 --> 01:04:47,700 Lakini baadhi ya watu kufanya hivyo. 1602 01:04:47,700 --> 01:04:49,160 [Kicheko] 1603 01:04:49,160 --> 01:04:51,760 DAVID J. Malan: Kwa hiyo mimi kutaja hili sasa, kwa sababu tu kama 1604 01:04:51,760 --> 01:04:54,400 wewe kusoma juu ya mambo katika vitabu au online, wewe ni kwenda kupata 1605 01:04:54,400 --> 01:04:55,990 mbalimbali ujumbe kutoka kwa walimu tofauti na 1606 01:04:55,990 --> 01:04:56,730 tofauti waandishi. 1607 01:04:56,730 --> 01:04:58,640 Na tu kutambua kwamba, functionally, wao uko 1608 01:04:58,640 --> 01:05:00,740 ujumla sawa, lakini kuwa thabiti. 1609 01:05:00,740 --> 01:05:02,850 Hivyo katika kesi hii, tutaweza standardize juu ya curly 1610 01:05:02,850 --> 01:05:04,650 braces wamejipanga hapa upande wa kushoto. 1611 01:05:04,650 --> 01:05:04,910 >> Wote haki. 1612 01:05:04,910 --> 01:05:07,040 Basi hebu kwenda mbele sasa na kukimbia hii, na kuona nini kinatokea 1613 01:05:07,040 --> 01:05:07,780 na mpango huu. 1614 01:05:07,780 --> 01:05:09,970 Matokeo nonswitch. 1615 01:05:09,970 --> 01:05:11,040 Kisha kukimbia nonswitch. 1616 01:05:11,040 --> 01:05:13,900 Nipe integer kati ya 0 na - hivyo si kwamba husika 1617 01:05:13,900 --> 01:05:16,480 tena, lakini nina kwenda tu kiholela kusema 42. 1618 01:05:16,480 --> 01:05:17,850 Na mimi ilichukua jibu sahihi. 1619 01:05:17,850 --> 01:05:20,430 Naam sasa, hebu kweli kuchukua hii katika mwelekeo tofauti. 1620 01:05:20,430 --> 01:05:22,070 Ni zinageuka kuna baadhi syntax nyingine sisi 1621 01:05:22,070 --> 01:05:23,480 wanaweza kutumia katika mpango. 1622 01:05:23,480 --> 01:05:27,310 Hapa ni kipande mpya ya syntax kwamba ni functionally sawa, 1623 01:05:27,310 --> 01:05:30,680 lakini tu utangulizi njia nyingine ya kuonyesha sisi wenyewe. 1624 01:05:30,680 --> 01:05:32,830 Hivyo hii ni kile kinachoitwa "kubadili kauli." Na 1625 01:05:32,830 --> 01:05:34,820 kubadili kauli inafanya kazi kama ifuatavyo. 1626 01:05:34,820 --> 01:05:37,580 Inachukua, katika mabano, thamani ya kwamba unataka 1627 01:05:37,580 --> 01:05:38,860 "Kubadili" juu. 1628 01:05:38,860 --> 01:05:41,490 Unataka tabia tofauti kulingana na thamani yake. 1629 01:05:41,490 --> 01:05:44,360 Hivyo hii ina maana kubadili juu ya thamani ya n. 1630 01:05:44,360 --> 01:05:45,480 Na nini maana ya hii? 1631 01:05:45,480 --> 01:05:50,530 Naam, kama n ni 1 au 2 au 3, kwenda mbele na magazeti nje "Wewe 1632 01:05:50,530 --> 01:05:52,680 ilichukua idadi kubwa "na kisha kuvunja. 1633 01:05:52,680 --> 01:05:55,720 sababu kwa ajili ya mapumziko ni kwamba njia C kazi ni kama 1634 01:05:55,720 --> 01:05:59,790 haraka kama anaona kesi kwamba mechi, ni kuanza utekelezaji 1635 01:05:59,790 --> 01:06:01,610 yote ya maadili ya chini yake. 1636 01:06:01,610 --> 01:06:04,580 Hivyo kama nina moja mstari wa kanuni, kama mimi kufanya hapa kwenye mstari 27, ni 1637 01:06:04,580 --> 01:06:05,360 anapata kunyongwa. 1638 01:06:05,360 --> 01:06:07,520 Kama mimi kuongeza line nyingine hapa, anapata kunyongwa. 1639 01:06:07,520 --> 01:06:09,350 Mstari mwingine hapa, anapata kunyongwa. 1640 01:06:09,350 --> 01:06:12,460 mpango tu ataacha utekelezaji nini hapo chini 1641 01:06:12,460 --> 01:06:14,680 husika kesi taarifa wakati mimi wazi 1642 01:06:14,680 --> 01:06:17,210 kusema "kuvunja." Hivyo vibaya. 1643 01:06:17,210 --> 01:06:19,220 Haki, katika kesi hii, kama matokeo. 1644 01:06:19,220 --> 01:06:22,130 Uchunguzi 4 au 5 au 6, vile vile, ni kwenda 1645 01:06:22,130 --> 01:06:23,160 kuchapa nje ujumbe. 1646 01:06:23,160 --> 01:06:24,410 Katika kesi hiyo, kati ya idadi. 1647 01:06:24,410 --> 01:06:25,200 Break. 1648 01:06:25,200 --> 01:06:28,160 Uchunguzi 7, 8, 9, 10, ni ya kwenda magazeti nje "Wewe ilichukua kubwa 1649 01:06:28,160 --> 01:06:28,950 namba ". Break. 1650 01:06:28,950 --> 01:06:31,290 Na kisha kuna literally Keyword kuitwa "default" 1651 01:06:31,290 --> 01:06:34,090 hiyo ni kwa ufanisi kama "mwingine" kujenga. 1652 01:06:34,090 --> 01:06:36,010 Hivyo mpya syntax, lakini kielimu, 1653 01:06:36,010 --> 01:06:37,060 kitu hapa yote mapya. 1654 01:06:37,060 --> 01:06:38,280 Ni kama tu Scratch. 1655 01:06:38,280 --> 01:06:41,040 Kama, mwingine kama, mwingine kama, aina ya block. 1656 01:06:41,040 --> 01:06:44,560 >> Basi hiyo ni toleo switched ya mpango huu. 1657 01:06:44,560 --> 01:06:46,280 Lakini taarifa kwamba sisi alifanya hivyo kwa namba hapa. 1658 01:06:46,280 --> 01:06:49,040 Hebu kufungua toleo la pili, tu kuonyesha 1659 01:06:49,040 --> 01:06:50,670 kitu kidogo zaidi zege. 1660 01:06:50,670 --> 01:06:52,840 Hivyo hapa tuna darasa badala yake. 1661 01:06:52,840 --> 01:06:55,540 Zinageuka unaweza kutumia swichi si tu juu ya integers, lakini juu ya 1662 01:06:55,540 --> 01:06:56,340 wahusika. 1663 01:06:56,340 --> 01:06:58,930 Si katika aina ya data zote, lakini angalau juu ya wahusika. 1664 01:06:58,930 --> 01:07:02,670 Hivyo hapa, tunaweza kufanya kitu kama kama thamani ya C kwamba 1665 01:07:02,670 --> 01:07:06,230 user typed katika, katika mstari 19, kwa kutumia kazi GetChar, 1666 01:07:06,230 --> 01:07:09,410 ni mtaji au Herufi za chini, hebu kutafsiri kama daraja, 1667 01:07:09,410 --> 01:07:11,340 na wanasema ilichukua daraja bora. 1668 01:07:11,340 --> 01:07:14,690 Na chini pamoja kauli kubadili, je, tuna nyingine 1669 01:07:14,690 --> 01:07:17,950 kesi kwa ajili ya "B" s na "C", na kadhalika. 1670 01:07:17,950 --> 01:07:19,780 Lakini hebu sasa pande zote nje ya mtu mwingine kitu. 1671 01:07:19,780 --> 01:07:21,130 Na tena, aina ya kuruka kwa njia ya 1672 01:07:21,130 --> 01:07:22,200 baadhi ya mifano hii. 1673 01:07:22,200 --> 01:07:26,990 Lakini ni kweli ili tuweze kuyatumia, sasa - 1674 01:07:26,990 --> 01:07:28,880 au kweli, tu kutafsiri yao sasa - 1675 01:07:28,880 --> 01:07:32,220 kwa C. 1676 01:07:32,220 --> 01:07:33,310 >> Hivyo basi mimi kwenda mbele na kufanya hili. 1677 01:07:33,310 --> 01:07:34,830 Mimi naenda kufungua faili mpya. 1678 01:07:34,830 --> 01:07:39,430 Na mimi naenda kufanya ni pamoja na . 1679 01:07:39,430 --> 01:07:42,770 Na kisha mimi naenda kufanya int kuu (utupu). 1680 01:07:42,770 --> 01:07:46,390 Hebu kuokoa faili hii kama loop.c. 1681 01:07:46,390 --> 01:07:48,280 Tu kama mfano. 1682 01:07:48,280 --> 01:07:49,910 Na mimi nina kwenda mbele na kufanya yafuatayo. 1683 01:07:49,910 --> 01:07:54,180 Nataka kuandika mpango tedious sana. 1684 01:07:54,180 --> 01:07:56,170 Hivyo 10. 1685 01:07:56,170 --> 01:07:58,862 Hebu kufanya hili. 1686 01:07:58,862 --> 01:07:59,320 9. 1687 01:07:59,320 --> 01:08:00,360 Wote haki. 1688 01:08:00,360 --> 01:08:02,120 Haraka kama wewe kuanza kufanya hili katika programu, wewe ni 1689 01:08:02,120 --> 01:08:03,490 pengine kufanya kitu kibaya. 1690 01:08:03,490 --> 01:08:04,950 Lakini tutaweza kuanza huko anyway. 1691 01:08:04,950 --> 01:08:05,430 Lo. 1692 01:08:05,430 --> 01:08:06,950 Hiyo ni kweli sawa. 1693 01:08:06,950 --> 01:08:08,230 7. 1694 01:08:08,230 --> 01:08:09,440 6. 1695 01:08:09,440 --> 01:08:10,750 5. 1696 01:08:10,750 --> 01:08:11,200 4. 1697 01:08:11,200 --> 01:08:12,450 Hakuna kitu ambacho kinaenda kutokea wakati sisi kupata 0. 1698 01:08:12,450 --> 01:08:13,290 3. 1699 01:08:13,290 --> 01:08:14,590 2. 1700 01:08:14,590 --> 01:08:15,630 1. 1701 01:08:15,630 --> 01:08:16,020 Sawa. 1702 01:08:16,020 --> 01:08:17,560 0. 1703 01:08:17,560 --> 01:08:18,689 Futa. 1704 01:08:18,689 --> 01:08:19,029 >> Wote haki. 1705 01:08:19,029 --> 01:08:20,029 Hivyo kurudi 0. 1706 01:08:20,029 --> 01:08:22,010 Hivyo mpango huu ambacho ni wazi anaenda kufanya kile sana 1707 01:08:22,010 --> 01:08:23,310 tediously anasema ni kwenda kufanya. 1708 01:08:23,310 --> 01:08:24,060 Ni kwenda na magazeti yote ya wale 1709 01:08:24,060 --> 01:08:25,290 maadili, kuanzia juu hadi chini. 1710 01:08:25,290 --> 01:08:27,140 Hivyo basi mimi kufanya kufanya kitanzi. 1711 01:08:27,140 --> 01:08:28,640 Na kisha - Lo. 1712 01:08:28,640 --> 01:08:29,700 Kufanya kitanzi. 1713 01:08:29,700 --> 01:08:31,479 Mimi nilikuwa katika saraka ya makosa. 1714 01:08:31,479 --> 01:08:33,300 Na sasa napenda kukimbia kitanzi. 1715 01:08:33,300 --> 01:08:34,140 Kuingia. 1716 01:08:34,140 --> 01:08:34,620 Safi. 1717 01:08:34,620 --> 01:08:35,270 Nzuri sana. 1718 01:08:35,270 --> 01:08:36,279 Nice, muda mrefu wa mpango. 1719 01:08:36,279 --> 01:08:38,109 >> Yote ya haki, lakini sasa hebu kufanya hili vizuri. 1720 01:08:38,109 --> 01:08:40,810 Kama ilivyo katika Scratch, wakati wewe kuanza kutumia looping 1721 01:08:40,810 --> 01:08:43,149 kujenga, badala ya kuiga na pasting yote ya 1722 01:08:43,149 --> 01:08:45,580 puzzle vipande, basi mimi kuanzisha hii kitu. 1723 01:08:45,580 --> 01:08:48,609 Hivyo katika C, kuna mbalimbali constructs looping, 1724 01:08:48,609 --> 01:08:50,540 moja ambayo inaonekana kama hii. 1725 01:08:50,540 --> 01:08:55,069 "Kwa" kitanzi ina mambo matatu, kutengwa kwa semicolons mbili. 1726 01:08:55,069 --> 01:08:57,770 Na kisha, ndani ya mwili wa kitanzi, hivyo kusema - 1727 01:08:57,770 --> 01:08:59,390 mambo ya ndani ya braces curly - 1728 01:08:59,390 --> 01:09:01,010 tunaweza kufanya kitu tena na tena. 1729 01:09:01,010 --> 01:09:02,310 Basi nini mimi hapa kwenye screen, hii ni 1730 01:09:02,310 --> 01:09:03,300 literally tu maoni. 1731 01:09:03,300 --> 01:09:05,380 / / Maana hiyo inakuja maoni. 1732 01:09:05,380 --> 01:09:06,180 Hii si code. 1733 01:09:06,180 --> 01:09:08,890 Hii ni tu Kiingereza maelezo, na mimi, binadamu. 1734 01:09:08,890 --> 01:09:11,300 >> Hivyo initializations, hali, na updates. 1735 01:09:11,300 --> 01:09:12,770 Naam, hebu angalia jinsi hii matendo. 1736 01:09:12,770 --> 01:09:15,520 Hii inaruhusu mimi rewrite ya programu hii kama ifuatavyo. 1737 01:09:15,520 --> 01:09:16,399 Kwa - 1738 01:09:16,399 --> 01:09:18,029 hivyo hapa anakuja kitanzi wangu - 1739 01:09:18,029 --> 01:09:19,439 int i - 1740 01:09:19,439 --> 01:09:21,330 inakuja variable inayoitwa "i" - 1741 01:09:21,330 --> 01:09:23,140 anapata initialized hadi 10. 1742 01:09:23,140 --> 01:09:25,260 Hivyo kuna initialization yangu. 1743 01:09:25,260 --> 01:09:29,450 Nataka kufanya hii kitanzi muda mrefu kama "i" ni zaidi au 1744 01:09:29,450 --> 01:09:30,899 sawa na 0. 1745 01:09:30,899 --> 01:09:32,880 Na juu ya kila iteration ya kitanzi hii, nataka 1746 01:09:32,880 --> 01:09:34,979 kufanya i -. 1747 01:09:34,979 --> 01:09:36,310 Hivyo tuliona + + Jumatatu. 1748 01:09:36,310 --> 01:09:37,660 - Ni kinyume. 1749 01:09:37,660 --> 01:09:39,410 Ni decrements thamani kwa 1. 1750 01:09:39,410 --> 01:09:43,319 Ndani ya kitanzi hii, nataka kwa kweli kufanya kitu. 1751 01:09:43,319 --> 01:09:46,390 Hivyo nina kwenda kwa kusema kitu kama printf. 1752 01:09:46,390 --> 01:09:48,939 Sitaki kusema 10 sasa, kwa sababu hii ni wazi ni tu 1753 01:09:48,939 --> 01:09:50,000 kwenda magazeti thamani sawa. 1754 01:09:50,000 --> 01:09:52,246 Nini nataka magazeti badala yake, pengine? 1755 01:09:52,246 --> 01:09:52,590 Yeah. 1756 01:09:52,590 --> 01:09:55,270 Hivyo "i." Hivyo% d, i. 1757 01:09:55,270 --> 01:09:57,340 >> Hivyo nina kwenda kuiba moja ya mawazo hayo kutoka mapema - 1758 01:09:57,340 --> 01:09:59,640 hii badala ya namba format - 1759 01:09:59,640 --> 01:10:01,620 na kisha chini hapa, chini, mimi itabidi kurudi 0, tu 1760 01:10:01,620 --> 01:10:02,710 kwa hatua nzuri. 1761 01:10:02,710 --> 01:10:04,740 Lakini sasa, nina zaidi succinct mpango. 1762 01:10:04,740 --> 01:10:07,490 Ni tu mistari michache, na mistari si baadhi 10 au 11. 1763 01:10:07,490 --> 01:10:09,440 Hebu kwenda haraka yangu chini hapa. 1764 01:10:09,440 --> 01:10:10,630 Remake kitanzi. 1765 01:10:10,630 --> 01:10:12,140 Rerun kitanzi. 1766 01:10:12,140 --> 01:10:13,570 Na inaonekana kuwa sawa. 1767 01:10:13,570 --> 01:10:15,550 Sasa, mpango hakuna zaidi ya kuvutia. 1768 01:10:15,550 --> 01:10:17,180 Lakini sasa mimi unaweza aina ya kitu kama hii. 1769 01:10:17,180 --> 01:10:18,970 Mimi naweza kubadili hii kwa 100. 1770 01:10:18,970 --> 01:10:21,400 Naweza kisha recompile mpango wangu. 1771 01:10:21,400 --> 01:10:23,360 Na kisha naweza kuendesha upya mpango wangu. 1772 01:10:23,360 --> 01:10:26,390 Na sasa unaendelea super-haraka juu ya kompyuta ya leo. 1773 01:10:26,390 --> 01:10:27,820 Lakini kuna nina - 1774 01:10:27,820 --> 01:10:29,620 na kweli, scrollback yangu buffer haina 1775 01:10:29,620 --> 01:10:30,890 hata kwenda mbali. 1776 01:10:30,890 --> 01:10:31,680 Kuna sisi kwenda. 1777 01:10:31,680 --> 01:10:34,090 Hivyo kuna tuna kila 100. 1778 01:10:34,090 --> 01:10:35,880 Lakini ni rahisi kufanya makosa hapa. 1779 01:10:35,880 --> 01:10:37,920 Nini kinaendelea kuwa tabia yanayotarajiwa kama mimi 1780 01:10:37,920 --> 01:10:41,150 ajali kufanya hivyo? 1781 01:10:41,150 --> 01:10:42,550 Hivyo anahisi kama usio. 1782 01:10:42,550 --> 01:10:44,670 Basi hebu angalia kama kompyuta kutenda. 1783 01:10:44,670 --> 01:10:47,020 >> Hivyo basi mimi kwenda mbele na kufanya kitanzi. 1784 01:10:47,020 --> 01:10:48,355 Na napenda kukimbia kitanzi. 1785 01:10:53,590 --> 01:10:55,210 Basi hebu kuja nyuma na kwamba katika muda tu. 1786 01:10:55,210 --> 01:10:56,720 Tutaweza basi kwamba kukimbia. 1787 01:10:56,720 --> 01:10:59,520 Kwa sababu kile lazima sisi kuhesabu hadi, minimally? 1788 01:10:59,520 --> 01:11:02,200 Pengine angalau bilioni 2, kama tuna kwamba bits wengi, na 1789 01:11:02,200 --> 01:11:03,660 sisi ni kutumia maadili mazuri. 1790 01:11:03,660 --> 01:11:04,890 Basi hebu kuruka nyuma hapa. 1791 01:11:04,890 --> 01:11:07,810 Licha ya aina hii ya tanzi, tuna nini wanaitwa wakati 1792 01:11:07,810 --> 01:11:09,430 matanzi. Hivyo, kama vile katika Scratch, wewe alikuwa Forever 1793 01:11:09,430 --> 01:11:11,240 vitalu, na wewe alikuwa vitalu Repeat. 1794 01:11:11,240 --> 01:11:13,270 Vile vile, katika C, wewe tu njia nyingine 1795 01:11:13,270 --> 01:11:14,260 ya kuonyesha mwenyewe. 1796 01:11:14,260 --> 01:11:17,110 Hivyo kuwa na wazo hili la wakati kitanzi kwamba utapata 1797 01:11:17,110 --> 01:11:18,860 kueleza mwenyewe tofauti kidogo. 1798 01:11:18,860 --> 01:11:21,490 Na kisha una kitu kinachoitwa kitanzi do-wakati, 1799 01:11:21,490 --> 01:11:24,200 ambayo inafanya kazi tofauti kidogo kama vizuri. 1800 01:11:24,200 --> 01:11:25,320 Na tutaweza tease hizi mbali zaidi ya muda. 1801 01:11:25,320 --> 01:11:28,630 >> Lakini hebu tuangalie moja hii ya mwisho hapa. 1802 01:11:28,630 --> 01:11:30,160 Kama sisi kwenda katika - 1803 01:11:30,160 --> 01:11:31,466 bado mbio. 1804 01:11:31,466 --> 01:11:32,770 Ni pretty usio. 1805 01:11:32,770 --> 01:11:36,870 Hivyo basi mimi kwenda katika chanya, na kuonyesha jinsi tunaweza kweli 1806 01:11:36,870 --> 01:11:39,410 serikali ya mtumiaji mchango mdogo kwa ufanisi zaidi. 1807 01:11:39,410 --> 01:11:40,910 Ni mpango pretty mfupi. 1808 01:11:40,910 --> 01:11:43,730 Na hapa sisi, katika kuu, int n tamko. 1809 01:11:43,730 --> 01:11:46,570 Basi nipe variable kuitwa n. Sasa, mimi literally kusema 1810 01:11:46,570 --> 01:11:48,340 "Kufanya." Na kisha mimi nimepata wazi curly 1811 01:11:48,340 --> 01:11:49,630 Brace, karibu curly Brace. 1812 01:11:49,630 --> 01:11:52,000 Na kisha taarifa, haki baada ya kwamba, anasema wakati n 1813 01:11:52,000 --> 01:11:53,790 ni chini ya 1. 1814 01:11:53,790 --> 01:11:55,300 Hivyo taarifa kwamba mistari haya - 1815 01:11:55,300 --> 01:11:56,740 19-24 - 1816 01:11:56,740 --> 01:11:59,450 kutunga pamoja kitanzi do-wakati. 1817 01:11:59,450 --> 01:12:01,280 Na tena, mpya syntax, si wazo jipya. 1818 01:12:01,280 --> 01:12:03,740 Ni tu njia nyingine ya looping, syntactically. 1819 01:12:03,740 --> 01:12:04,890 Hiyo ni nini hii nini? 1820 01:12:04,890 --> 01:12:08,000 Kufanya yafuatayo wakati n ni chini ya 1. 1821 01:12:08,000 --> 01:12:09,080 Basi nini nataka kufanya? 1822 01:12:09,080 --> 01:12:11,390 Mimi kudai kwamba wewe nipe sifuri. 1823 01:12:11,390 --> 01:12:14,110 Kisha mimi kwa kweli kujaribu kupata integer kutoka kwa mtumiaji. 1824 01:12:14,110 --> 01:12:16,740 Lakini katika suala la utaratibu wa shughuli hapa, kwa sababu 1825 01:12:16,740 --> 01:12:21,850 wakati hali ni chini hapa, mimi nina kisha kwenda kuangalia, ni n 1826 01:12:21,850 --> 01:12:23,100 chini ya 1? 1827 01:12:23,100 --> 01:12:24,600 Hivyo kudhani kuwa user - 1828 01:12:24,600 --> 01:12:26,450 baada ya kuwa alidai katika njia hii - 1829 01:12:26,450 --> 01:12:29,190 aina katika 0 thamani. 1830 01:12:29,190 --> 01:12:34,510 Hali hii ni kwenda kuwa kweli au uongo? 1831 01:12:34,510 --> 01:12:35,820 Naam, ni kweli kwenda kuwa kweli. 1832 01:12:35,820 --> 01:12:38,700 Kwa sababu ni n 0, na ni chini ya 0 1. 1833 01:12:38,700 --> 01:12:40,140 Hiyo ni nini kwamba kuashiria? 1834 01:12:40,140 --> 01:12:41,160 Kufanya hivyo tena. 1835 01:12:41,160 --> 01:12:41,990 Kufanya hivyo tena. 1836 01:12:41,990 --> 01:12:42,640 Kufanya hivyo tena. 1837 01:12:42,640 --> 01:12:46,080 Mara moja tu sharti kwamba kutathmini kwa uongo. 1838 01:12:46,080 --> 01:12:47,510 Kama mimi aina katika 42. 1839 01:12:47,510 --> 01:12:49,690 Naam hakuna, 42 ni si chini ya 1. 1840 01:12:49,690 --> 01:12:52,320 Basi kitanzi hii inafanywa utekelezaji. 1841 01:12:52,320 --> 01:12:54,650 Na hivyo katika hatua hiyo, mpango watasema, shukrani kwa ajili ya 1842 01:12:54,650 --> 01:12:57,530 42, katika kesi hii. 1843 01:12:57,530 --> 01:13:00,320 Sasa una njia hii ya kuonyesha mwenyewe - 1844 01:13:00,320 --> 01:13:02,360 Sisi lazima si kusubiri kwa hili hadi mwisho. 1845 01:13:02,360 --> 01:13:03,620 Ni kwenda kuchukua muda. 1846 01:13:03,620 --> 01:13:04,990 Kuendelezwa wakati mwingine, labda. 1847 01:13:04,990 --> 01:13:08,050 >> Lakini sasa, una uwezo wa hopefully kuelewa 1848 01:13:08,050 --> 01:13:09,060 kidogo ya ucheshi geek. 1849 01:13:09,060 --> 01:13:11,560 Apologies. 1850 01:13:11,560 --> 01:13:13,620 Hii si mwakilishi wa ucheshi katika sayansi ya kompyuta 1851 01:13:13,620 --> 01:13:14,870 dunia, lakini ni cute. 1852 01:13:21,020 --> 01:13:23,890 Mwisho [anacheka] Hebu kumbuka kwamba. 1853 01:13:23,890 --> 01:13:25,750 Na sisi kuona juu ya Jumatatu. 1854 01:13:25,750 --> 01:13:31,629 [Applause]