1 00:00:00,000 --> 00:00:05,410 2 00:00:05,410 --> 00:00:07,640 >> DOUG LLOYD: zote haki, hivyo hebu majadiliano juu ya mizunguko. 3 00:00:07,640 --> 00:00:10,015 Hivyo mizunguko ni aina ya baridi kwa sababu wao kuruhusu mpango wako 4 00:00:10,015 --> 00:00:12,050 kutekeleza mstari wa kanuni tena na tena na tena. 5 00:00:12,050 --> 00:00:15,600 Tena na tena, bila ya kuwa na nakala na kuweka au vinginevyo kurudia kwao. 6 00:00:15,600 --> 00:00:17,630 Kuna tatu kuu aina ya mizunguko utaona. 7 00:00:17,630 --> 00:00:21,010 Pengine utasikia kuwa na nafasi ya kutumia kila mmoja kama wewe maendeleo kwa njia CS50. 8 00:00:21,010 --> 00:00:22,940 Baadhi ya mizunguko hizi ni mzuri ukoo na wewe kutoka Scratch, 9 00:00:22,940 --> 00:00:25,814 hivyo tena, kama tulivyofanya kwa conditionals, tutaweza kuweka yao juu bega kwa bega 10 00:00:25,814 --> 00:00:28,930 kama kuna mfano tunaweza kuchora. 11 00:00:28,930 --> 00:00:33,600 >> Kwanza ni milele kutoka Scratch, ambayo inalinganishwa na wakati (wa kweli). 12 00:00:33,600 --> 00:00:35,390 Hii ni nini sisi kuwaita kitanzi usio. 13 00:00:35,390 --> 00:00:38,560 Mstari wa kanuni kati ya curly braces, kiasi kama vipande puzzle 14 00:00:38,560 --> 00:00:41,190 kuwa fit ndani ya C ya milele kuzuia, 15 00:00:41,190 --> 00:00:45,290 nitafanya tena na tena toka juu hadi chini, tena na tena na tena, 16 00:00:45,290 --> 00:00:46,085 milele. 17 00:00:46,085 --> 00:00:48,710 Baada ya yote, kama unakumbuka yetu mjadala wa maneno Boolean, 18 00:00:48,710 --> 00:00:51,060 kweli ni kweli daima. 19 00:00:51,060 --> 00:00:53,250 Hivyo kama sisi ni kufanya kitu ili mradi kweli 20 00:00:53,250 --> 00:00:58,227 ni true-- inaonekana silly-- kidogo kweli ni kweli daima, hivyo itabidi daima kukimbia. 21 00:00:58,227 --> 00:01:00,060 Kutakuwa na kukimbia milele na milele na milele mpaka sisi 22 00:01:00,060 --> 00:01:02,900 kutafuta njia ya kuvunja nje ya hiyo kwa mapumziko kauli, ambayo tena, 23 00:01:02,900 --> 00:01:06,350 tuliona kidogo iliyopita sisi walikuwa wanazungumza juu ya kubadili. 24 00:01:06,350 --> 00:01:08,725 >> Au vinginevyo kuua tu wetu mpango, ambayo kwa bahati, 25 00:01:08,725 --> 00:01:11,110 kama wewe milele kupata mwenyewe katika hali na kitanzi usio 26 00:01:11,110 --> 00:01:13,484 na wewe sijui jinsi ya kuacha mpango wako kutoka mbio. 27 00:01:13,484 --> 00:01:16,527 Hit tu ya kudhibiti na C na kwamba kutakuwa na kuua mpango wako kwa ajili yenu. 28 00:01:16,527 --> 00:01:18,360 Lakini hii, tena, ni aitwaye kitanzi usio. 29 00:01:18,360 --> 00:01:19,818 Ni kitanzi kwamba inakwenda milele. 30 00:01:19,818 --> 00:01:22,570 31 00:01:22,570 --> 00:01:25,610 Sasa, wakati tanzi si daima usio na mipaka, kwa sababu pia 32 00:01:25,610 --> 00:01:27,880 tunaweza kuchukua nafasi ya Boolean kujieleza na kitu 33 00:01:27,880 --> 00:01:29,867 muhimu zaidi kidogo kuliko tu ya kweli. 34 00:01:29,867 --> 00:01:30,950 Hivyo hapa ni mfano mwingine. 35 00:01:30,950 --> 00:01:34,600 Wakati na baadhi Boolean kujieleza na braces curly kisha. 36 00:01:34,600 --> 00:01:38,310 Hiyo ni pretty much sawa kurudia mpaka, kutoka mwanzo. 37 00:01:38,310 --> 00:01:40,700 Ingawa katika pili, mimi itabidi kuelezea tofauti. 38 00:01:40,700 --> 00:01:44,310 >> Hivyo katika C, kama kujieleza Boolean ndani ya kitanzi wakati 39 00:01:44,310 --> 00:01:47,980 kutathmini kwa kweli, mistari ya kificho kati ya braces curly 40 00:01:47,980 --> 00:01:51,900 nitafanya tena na tena tena na tena na juu ya mpaka kujieleza Boolean 41 00:01:51,900 --> 00:01:55,174 kutathmini kwa uongo. 42 00:01:55,174 --> 00:01:57,340 Hivyo kwa mfano, waweza kuwa na aina fulani ya kukabiliana. 43 00:01:57,340 --> 00:02:01,440 Hivyo kusema wewe mwanzoni mwa kitanzi hii kusema int x sawa sifuri. 44 00:02:01,440 --> 00:02:06,370 Wakati x ni chini ya 100, kufanya michache mambo ndani ya kwamba braces curly, 45 00:02:06,370 --> 00:02:10,570 kisha katika mwisho wa kitanzi yako, unasema x pamoja pamoja, wewe ni incrementing x. 46 00:02:10,570 --> 00:02:13,360 Hatimaye x kupata 100 na wewe 47 00:02:13,360 --> 00:02:15,760 kuacha kwa sababu hali x ni chini ya 100 48 00:02:15,760 --> 00:02:19,416 tena kuwa kweli kama Mara tu x ni sawa na 100. 49 00:02:19,416 --> 00:02:21,820 100 ni si chini ya 100. 50 00:02:21,820 --> 00:02:25,870 >> Sasa kwa kiasi fulani confusingly, tabia ya kuzuia mwanzo ni kuachwa. 51 00:02:25,870 --> 00:02:29,110 Hivyo kuwa makini kweli kama hii ni kuliingia yako ya kwanza katika kutumia mizunguko. 52 00:02:29,110 --> 00:02:33,630 Kimsingi, kurudia mpaka kuzuia katika Scratch 53 00:02:33,630 --> 00:02:35,970 kurudia kitu tena na tena na tena, 54 00:02:35,970 --> 00:02:40,460 mpaka kujieleza, Boolean kujieleza katika hexagons ni kweli. 55 00:02:40,460 --> 00:02:43,860 Hivyo itakuwa kuendelea kufanya mpaka ni kweli. 56 00:02:43,860 --> 00:02:48,881 Wakati huo huo, wakati kitanzi mapenzi kuendelea kufanya hivyo mpaka ni ya uongo. 57 00:02:48,881 --> 00:02:51,630 Hivyo wao ni sawa kabisa, lakini kuna tofauti kidogo tu kwamba 58 00:02:51,630 --> 00:02:55,140 kuwa makini ya hasa kama wewe kufanya kuliingia yako ya kwanza kutoka kipindi cha mpito 59 00:02:55,140 --> 00:02:58,149 kwa Scratch katika c. 60 00:02:58,149 --> 00:03:00,190 Aina ya pili ya kitanzi ni kweli pretty sawa. 61 00:03:00,190 --> 00:03:02,860 Ni wito kufanya wakati kitanzi. 62 00:03:02,860 --> 00:03:07,060 Kitanzi hii nitafanya mistari yote wa kanuni kati ya braces curly mara moja, 63 00:03:07,060 --> 00:03:09,530 na basi itakuwa kuangalia kujieleza Boolean. 64 00:03:09,530 --> 00:03:11,700 Kama kujieleza Boolean kutathmini kwa kweli, 65 00:03:11,700 --> 00:03:14,340 kutakuwa na kurudi nyuma na kurudia kwamba mchakato tena na tena 66 00:03:14,340 --> 00:03:17,690 na juu ya mpaka Boolean kujieleza kutathmini kwa uongo. 67 00:03:17,690 --> 00:03:23,370 Hivyo kitanzi hii, tofauti na kitanzi wakati, ni uhakika ya kuendesha angalau mara moja. 68 00:03:23,370 --> 00:03:26,080 Hii inaweza kuwa pretty muhimu. 69 00:03:26,080 --> 00:03:28,011 >> Mwisho, tuna kwa kitanzi. 70 00:03:28,011 --> 00:03:30,010 Kwa mizunguko ni aina ya syntactically unattractive 71 00:03:30,010 --> 00:03:32,330 na kuna mengi kwenda juu ya hapa, hivyo kuzaa na mimi 72 00:03:32,330 --> 00:03:34,640 kama sisi kujaribu na kuvunja vipande hayo mbali. 73 00:03:34,640 --> 00:03:36,810 Kwa ujumla, kesi ya matumizi ya kwa kitanzi ni wewe 74 00:03:36,810 --> 00:03:40,136 wanataka kurudia kitu a maalum ya idadi ya nyakati. 75 00:03:40,136 --> 00:03:42,010 Katika mfano huu hapa, Nina kuzuia kurudia 76 00:03:42,010 --> 00:03:44,010 kutoka Scratch, ambayo ni sawa na kwa kitanzi 77 00:03:44,010 --> 00:03:47,340 katika C, kurudia kitu mara 10. 78 00:03:47,340 --> 00:03:49,250 Na kwa kitanzi juu ya kushoto huko, ambayo 79 00:03:49,250 --> 00:03:51,410 ni kitanzi nne ambazo ingekuwa kufanya kitu kimoja. 80 00:03:51,410 --> 00:03:52,570 Hii aliamua kwenda mara 10. 81 00:03:52,570 --> 00:03:56,720 Kuhesabu kutoka sifuri, sisi increment kila mwanya wa kitanzi. 82 00:03:56,720 --> 00:03:59,220 Na sisi kuendelea kufanya hivyo mpaka i ni chini ya 10. 83 00:03:59,220 --> 00:04:00,134 >> Hivyo kile kinachotokea? 84 00:04:00,134 --> 00:04:01,550 Kuna mengi yote ya kificho huko. 85 00:04:01,550 --> 00:04:03,424 Hebu kuvunja chini kwa kile kinachotokea hatua 86 00:04:03,424 --> 00:04:05,684 kwa hatua kama sisi kuchimba kupitia kwa kitanzi. 87 00:04:05,684 --> 00:04:08,350 Jambo la kwanza kwamba kilichotokea ni kukabiliana na kutofautiana ni kituo cha. 88 00:04:08,350 --> 00:04:11,970 Kila kitu kwa upande wa kushoto wa kwanza semicolon ndani ya mabano 89 00:04:11,970 --> 00:04:12,970 ni kunyongwa. 90 00:04:12,970 --> 00:04:15,180 Katika kesi hiyo, sisi ni akisema int i sawa 0. 91 00:04:15,180 --> 00:04:18,709 Kutangaza variable mpya iitwayo i, kwamba vigezo ni aina integer 92 00:04:18,709 --> 00:04:22,570 na sisi ni kusema thamani ndani ya kwamba kutofautiana ni kwenda kuwa sifuri. 93 00:04:22,570 --> 00:04:25,480 >> Jambo la pili sisi kufanya ni sisi kisha mara moja kutathmini 94 00:04:25,480 --> 00:04:26,750 kujieleza Boolean. 95 00:04:26,750 --> 00:04:30,100 Kujieleza Boolean ni katika katikati ya semicolons mbili. 96 00:04:30,100 --> 00:04:31,360 Mimi ni chini ya 10. 97 00:04:31,360 --> 00:04:32,410 Hiyo ni kweli hapa, sawa? 98 00:04:32,410 --> 00:04:36,030 Sisi tu alisema i ni sawa na sifuri, na hivyo 0 ni chini ya 10, 99 00:04:36,030 --> 00:04:38,040 na hivyo hali hiyo Ni kweli na sisi sasa 100 00:04:38,040 --> 00:04:40,640 kuendelea kutekeleza mwili wa kitanzi. 101 00:04:40,640 --> 00:04:41,480 Kama ilivyokuwa uongo. 102 00:04:41,480 --> 00:04:46,380 Kama, kwa mfano, mimi alisema badala ya i sawa 0 kuna nilivyosema i sawa 15, 103 00:04:46,380 --> 00:04:47,820 int i sawa 15. 104 00:04:47,820 --> 00:04:51,450 Naam 15 ni si chini ya 10, hivyo sisi kamwe kuingia kwenye mwili wa kitanzi 105 00:04:51,450 --> 00:04:55,450 kwa sababu kujieleza Boolean ingekuwa kuna kutathmini kuwa uongo. 106 00:04:55,450 --> 00:04:59,060 >> Baada ya sisi kwenda kwa njia ya kutoka juu hadi chini, sisi kukutana kwamba kufunga curly brace, 107 00:04:59,060 --> 00:05:00,830 Jambo la tatu kinatokea. 108 00:05:00,830 --> 00:05:03,840 Kutofautiana kukabiliana ni incremented, au tuseme, mistari 109 00:05:03,840 --> 00:05:07,790 ya kanuni za kauli baada semicolon pili ndani ya 110 00:05:07,790 --> 00:05:10,500 kwa mizunguko mabano ni kunyongwa. 111 00:05:10,500 --> 00:05:13,250 Hivyo sisi kuanza nje kwa akisema int i sawa 0. 112 00:05:13,250 --> 00:05:15,770 Kisha sisi kuangalia kama au kujieleza Boolean ni kweli. 113 00:05:15,770 --> 00:05:17,469 0 ni chini ya 10 hivyo ni kweli. 114 00:05:17,469 --> 00:05:19,510 Hivyo sisi ni kwenda kuendelea ndani ya mwili kitanzi. 115 00:05:19,510 --> 00:05:22,676 Mambo kutokea ndani ya kitanzi, na wakati sisi kukutana kwamba kufunga curly 116 00:05:22,676 --> 00:05:25,660 Brace, jambo la pili sisi kufanya ni tunasema i pamoja, pamoja. 117 00:05:25,660 --> 00:05:28,860 Nilikuwa sifuri sasa i ni moja. 118 00:05:28,860 --> 00:05:33,100 Basi, sisi tena kuangalia thamani ya kujieleza Boolean katikati. 119 00:05:33,100 --> 00:05:34,900 Moja ni chini ya 10. 120 00:05:34,900 --> 00:05:38,325 Hivyo tutaweza kwenda kwa njia hii mchakato tena na tena. 121 00:05:38,325 --> 00:05:40,590 Tutaweza kupata kufunga curly brace tena. 122 00:05:40,590 --> 00:05:44,090 Tutaweza increment i kutoka 1 hadi 2 na 2-3. 123 00:05:44,090 --> 00:05:48,290 Na kadhalika na kadhalika na kadhalika, mpaka hatimaye thamani i huwa 10. 124 00:05:48,290 --> 00:05:49,950 Ni 10 chini ya 10? 125 00:05:49,950 --> 00:05:51,200 Hakuna 126 00:05:51,200 --> 00:05:53,800 Kuhesabu kutoka 0, tumeenda kwa njia ya 10 iterations ya kitanzi. 127 00:05:53,800 --> 00:05:57,204 Tumekuwa alirudia mara 10, tu kama tulivyofanya katika kuzuia Scratch. 128 00:05:57,204 --> 00:05:59,370 Na hivyo ndiyo kimsingi mchakato kwa kitanzi nne. 129 00:05:59,370 --> 00:06:01,630 >> Sasa kuzichukua kanuni halisi na kuweka 130 00:06:01,630 --> 00:06:05,120 katika baadhi tu ya msingi kauli ujumla. 131 00:06:05,120 --> 00:06:06,550 Hapa ni nini kinatokea. 132 00:06:06,550 --> 00:06:09,290 Taarifa zote katika kuanza ni kunyongwa kwanza. 133 00:06:09,290 --> 00:06:11,260 Unaweza kuwa na zaidi ya moja. 134 00:06:11,260 --> 00:06:13,440 Kisha, kujieleza Boolean ni checked. 135 00:06:13,440 --> 00:06:17,850 Kama usemi kutathmini kwa kweli, kutekeleza mwili kitanzi wakati mmoja. 136 00:06:17,850 --> 00:06:21,060 Kama usemi kutathmini kwa uongo, sisi ni kosa. 137 00:06:21,060 --> 00:06:23,040 Hatuna kutekeleza mwili wa kitanzi wakati wote. 138 00:06:23,040 --> 00:06:25,530 Baada tumekuwa kunyongwa mwili kitanzi wakati mmoja, 139 00:06:25,530 --> 00:06:29,487 sisi kisha kufanya kile ambacho ni katika nyongeza sehemu huko. 140 00:06:29,487 --> 00:06:31,820 Ambayo ni kawaida kwenda kuwa kitu kama i pamoja, pamoja na 141 00:06:31,820 --> 00:06:34,510 au kitu kama hicho, kwamba modifies kukabiliana kutofautiana. 142 00:06:34,510 --> 00:06:37,390 Kisha, baada ya sisi increment, sisi kuangalia kujieleza tena 143 00:06:37,390 --> 00:06:41,120 na kurudia hatua hizo tena na tena na juu ya mpaka kujieleza ni 144 00:06:41,120 --> 00:06:42,890 kweli tena. 145 00:06:42,890 --> 00:06:44,469 >> Kwa hiyo kile kesi kwa kitanzi matumizi ni? 146 00:06:44,469 --> 00:06:46,760 Kutumia matumizi kitanzi wakati wakati unataka kitanzi kurudia 147 00:06:46,760 --> 00:06:51,200 idadi isiyojulikana ya nyakati, lakini ni uwezekano wanaweza kukimbia yote. 148 00:06:51,200 --> 00:06:53,940 Mfano kweli ya kawaida ya wakati looping inatumiwa 149 00:06:53,940 --> 00:06:56,480 ni kukimbia kudhibiti mtiririko kwa ajili ya mchezo. 150 00:06:56,480 --> 00:06:59,040 Unaweza kujua ni muda gani user ni kwenda kuwa kucheza, 151 00:06:59,040 --> 00:07:01,440 lakini unataka kuweka kufanya kitu kimoja. 152 00:07:01,440 --> 00:07:04,970 Kuhuisha nafasi za sprites mbalimbali juu ya bodi. 153 00:07:04,970 --> 00:07:07,490 Unataka kuweka mambo kusonga wakati wote, 154 00:07:07,490 --> 00:07:09,110 lakini nyinyi hamjui wakati user ni kwenda kuacha kucheza 155 00:07:09,110 --> 00:07:10,450 au wakati wao wanaenda kukimbia nje ya maisha. 156 00:07:10,450 --> 00:07:12,741 Hivyo kitanzi wakati ni kweli nzuri kwa ajili ya kitu kama hicho. 157 00:07:12,741 --> 00:07:14,130 Hiyo ni nzuri matumizi ya kesi. 158 00:07:14,130 --> 00:07:16,230 >> Kwa kufanya wakati kitanzi, ni pretty sawa. 159 00:07:16,230 --> 00:07:19,746 Unataka kitanzi kurudia haijulikani idadi ya nyakati, lakini angalau mara moja. 160 00:07:19,746 --> 00:07:22,370 Unaweza kutumia hii kwa mchezo pia, lakini matumizi ya kawaida kesi kweli 161 00:07:22,370 --> 00:07:24,420 ni kusababisha mtumiaji kwa ajili ya pembejeo. 162 00:07:24,420 --> 00:07:28,609 Kwa ujumla, unaweza kusema kitu kama, nipe sifuri, 163 00:07:28,609 --> 00:07:30,650 na unaweza kuweka kwamba ndani ya kufanya wakati kitanzi. 164 00:07:30,650 --> 00:07:33,900 Hivyo itakuwa daima kuuliza yao katika mara moja angalau kwa sifuri. 165 00:07:33,900 --> 00:07:36,850 Kama wao kukupa sifuri, unaweza kuvunja nje ya kitanzi. 166 00:07:36,850 --> 00:07:37,599 Unaweza kufanywa. 167 00:07:37,599 --> 00:07:39,900 Kujieleza Boolean katika kufanya wakati inaweza kuwa ni uongo. 168 00:07:39,900 --> 00:07:41,137 >> Na huwezi kuwauliza tena. 169 00:07:41,137 --> 00:07:44,470 Kama wao kukupa namba hasi ambapo wao aina baadhi neno au kitu ambacho ni 170 00:07:44,470 --> 00:07:46,630 si muhimu kweli kweli kwa wewe, unaweza kutumia 171 00:07:46,630 --> 00:07:49,770 Je, kitanzi wakati wa kurudi nyuma na kufanya tena na tena na tena. 172 00:07:49,770 --> 00:07:52,410 Wewe dhahiri wanataka kuuliza wao kukupa idadi mara moja, 173 00:07:52,410 --> 00:07:56,350 lakini wewe sijui mara ngapi baada wapate kuwa wadudu. 174 00:07:56,350 --> 00:08:00,540 Na hivyo kufanya wakati ni matumizi makubwa kesi kwa kusababisha mtumiaji kwa ajili ya pembejeo. 175 00:08:00,540 --> 00:08:03,060 Na kwa mizunguko kutumia kesi kawaida ni wakati 176 00:08:03,060 --> 00:08:06,230 unataka kurudia kitanzi idadi Diskret wa nyakati, 177 00:08:06,230 --> 00:08:08,230 ingawa waweza si kujua idadi ya nyakati 178 00:08:08,230 --> 00:08:10,040 wakati mpango ni ulioandaliwa. 179 00:08:10,040 --> 00:08:15,510 >> Hivyo kwa mfano, labda una mpango ambapo kuchochea mtumiaji kwa idadi. 180 00:08:15,510 --> 00:08:17,660 Na wao kuingia 100. 181 00:08:17,660 --> 00:08:20,510 Na kisha yako kwa kitanzi mapenzi katika kesi hiyo kukimbia mara 100. 182 00:08:20,510 --> 00:08:22,480 Au labda wao kuingia 1,000 katika mpango wako 183 00:08:22,480 --> 00:08:24,570 na kisha kukimbia kitanzi mara 1,000. 184 00:08:24,570 --> 00:08:26,987 Ni idadi maalum ya nyakati. 185 00:08:26,987 --> 00:08:28,820 Wao si lazima kujua nini idadi hiyo 186 00:08:28,820 --> 00:08:31,010 ni wakati mpango ni ulioandaliwa. 187 00:08:31,010 --> 00:08:35,010 Siyo kama kitanzi wakati ambapo inaweza kuwa kubwa. 188 00:08:35,010 --> 00:08:37,127 Ni badala idadi kwamba wewe tu hawajui. 189 00:08:37,127 --> 00:08:39,210 Sasa hata mimi wameweza ilivyoainishwa hizi kesi zote matumizi, 190 00:08:39,210 --> 00:08:41,501 unapaswa kujua kwamba katika pretty much kila hali, 191 00:08:41,501 --> 00:08:44,110 unaweza interchange zote tatu ya mizunguko hizi. 192 00:08:44,110 --> 00:08:46,890 Unaweza kutumia kwa kitanzi ambapo ingekuwa vinginevyo kutumia kitanzi wakati. 193 00:08:46,890 --> 00:08:49,860 Unaweza kutumia kwa kitanzi popote d kutumia kitanzi do-wakati, na kadhalika. 194 00:08:49,860 --> 00:08:53,680 Ni inaweza kuwa gumu kidogo wakati mwingine, hivyo kwa ujumla ni mazoezi mazuri 195 00:08:53,680 --> 00:08:55,140 kuambatana na matumizi ya kawaida kesi. 196 00:08:55,140 --> 00:08:57,599 Kutumia kitanzi do-wakati kama wewe alitaka kitu mara moja, angalau. 197 00:08:57,599 --> 00:09:00,514 Kutumia kwa kitanzi kama unataka kufanya kitu idadi maalum ya nyakati. 198 00:09:00,514 --> 00:09:03,730 Baada ya yote, kwamba ni kwa nini kuna watu aina tatu tofauti ya mizunguko. 199 00:09:03,730 --> 00:09:06,172 >> Ili waweze kutumiwa katika mazingira ya haki. 200 00:09:06,172 --> 00:09:07,880 Lakini unaweza interchange yao kama unataka. 201 00:09:07,880 --> 00:09:10,790 Kama wewe kujisikia vizuri na wakati tanzi na wewe siku zote wanataka kutumia wakati matanzi. 202 00:09:10,790 --> 00:09:12,623 Ni kitu ambacho unaweza kufanya, ingawa 203 00:09:12,623 --> 00:09:15,590 inaweza kuwa syntactically kidogo gumu, ambapo kwa kitanzi 204 00:09:15,590 --> 00:09:17,850 itakuwa mengi moja kwa moja zaidi. 205 00:09:17,850 --> 00:09:21,100 >> Jina langu ni Doug Lloyd na hii ni CS50. 206 00:09:21,100 --> 00:09:22,688