1 00:00:00,000 --> 00:00:02,952 >> [Music kucheza] 2 00:00:02,952 --> 00:00:11,316 3 00:00:11,316 --> 00:00:13,284 >> [Music kucheza] 4 00:00:13,284 --> 00:00:18,722 5 00:00:18,722 --> 00:00:19,680 DAVID Malan: zote haki. 6 00:00:19,680 --> 00:00:21,983 Hii ni CS50. 7 00:00:21,983 --> 00:00:24,108 [MUSIC KUCHEZA Tritonal, Cash Cash,  "Untouchable"] 8 00:00:24,108 --> 00:01:40,846 9 00:01:40,846 --> 00:01:41,844 [Music kucheza] 10 00:01:41,844 --> 00:01:45,337 SPIKA 1: Mimi nina kwenda Ufaransa, na wewe ni kwenda, pia. 11 00:01:45,337 --> 00:01:48,331 [Music kucheza] 12 00:01:48,331 --> 00:02:38,100 13 00:02:38,100 --> 00:02:41,930 DAVID Malan: Hii ni CS50, kuanzishwa Chuo Kikuu cha Harvard 14 00:02:41,930 --> 00:02:44,520 kwa akili makampuni ya sayansi ya kompyuta 15 00:02:44,520 --> 00:02:47,940 na sanaa ya program-- na kwa mara ya kwanza katika historia, 16 00:02:47,940 --> 00:02:49,800 Chuo Kikuu cha Yale pia. 17 00:02:49,800 --> 00:02:53,830 Kwa kweli, iwe uko hapa katika Cambridge au katika New Haven au Miami au St. Louis 18 00:02:53,830 --> 00:02:55,550 au Amsterdam au mahali popote duniani kote 19 00:02:55,550 --> 00:03:00,080 kuchukua CS50, kompyuta sayansi E50, CS50x, CS50 AP, 20 00:03:00,080 --> 00:03:02,090 sisi wote ni kitu kimoja na hicho. 21 00:03:02,090 --> 00:03:04,490 Karibu CS50. 22 00:03:04,490 --> 00:03:05,380 >> Nini sisi have-- 23 00:03:05,380 --> 00:03:06,348 >> [Makofi] 24 00:03:06,348 --> 00:03:07,800 >> [Anacheka] 25 00:03:07,800 --> 00:03:10,220 >> [Makofi] 26 00:03:10,220 --> 00:03:13,610 27 00:03:13,610 --> 00:03:16,920 >> Hivyo mimi alifanya makosa mwenyewe baadhi wakati iliyopita wakati mimi ilianza chuo. 28 00:03:16,920 --> 00:03:21,580 Na I got chuo, na niliamua kusema ukweli, fimbo ndani ya eneo la faraja yangu. 29 00:03:21,580 --> 00:03:24,475 Mimi kuishia kutangaza viwango, au kubwa, za serikali. 30 00:03:24,475 --> 00:03:27,880 Ant kwamba ilikuwa zaidi kazi ya me kuwa pretty ukoo na serikali 31 00:03:27,880 --> 00:03:31,270 au angalau historia au mimi kwa kweli walipenda sheria ya kikatiba katika shule ya sekondari. 32 00:03:31,270 --> 00:03:34,150 Na hivyo nilipofika hapa, mimi aina ya gravitated kuelekea mambo 33 00:03:34,150 --> 00:03:35,800 na ambayo nilikuwa tayari ukoo. 34 00:03:35,800 --> 00:03:36,300 Haki? 35 00:03:36,300 --> 00:03:38,167 Hasha mimi kufanya vibaya darasani. 36 00:03:38,167 --> 00:03:40,250 Mimi hakika alitaka kukaa ndani ya eneo la faraja yangu, 37 00:03:40,250 --> 00:03:43,010 na haikuwa mpaka mwaka sophomore kwamba mimi hatimaye 38 00:03:43,010 --> 00:03:46,820 aliamka ujasiri wa hatua ya mguu darasani aitwaye CS50. 39 00:03:46,820 --> 00:03:51,150 Na katika hatua hiyo, je, mimi hatimaye kutambua kwamba, Mungu wangu, kazi za nyumbani naweza kweli 40 00:03:51,150 --> 00:03:51,910 kuwa na furaha. 41 00:03:51,910 --> 00:03:54,410 >> Hakika, nilikuwa mmoja wa watoto wale kwamba siku ya Ijumaa jioni wakati 42 00:03:54,410 --> 00:03:57,640 P-seti itakuwa iliyotolewa, I aliamua kwenda nyuma ya chumba yangu na kupiga mbizi 43 00:03:57,640 --> 00:03:58,790 katika P-seti usiku. 44 00:03:58,790 --> 00:04:01,606 Na kwa ajili yangu, hiyo ilikuwa ni ishara kwamba hii ilikuwa ni uwanja kwa ajili yangu. 45 00:04:01,606 --> 00:04:04,480 Lakini nini ni muhimu zaidi ilikuwa ukweli kwamba mimi kupata up ujasiri huu 46 00:04:04,480 --> 00:04:08,000 kuchunguza maji usio wa kawaida kwangu na kupata zaidi ya zone yangu mwenyewe faraja 47 00:04:08,000 --> 00:04:12,320 na kusema ukweli, mimi tu alikuwa na uwezo wa kufanya hivyo sophomore mwaka kwa kuchukua darasa hili 48 00:04:12,320 --> 00:04:13,050 kupita / kushindwa. 49 00:04:13,050 --> 00:04:16,470 >> Hakika, ilikuwa ni siku ya mwisho kabisa kwamba Mimi hatimaye switched juu na hatimaye 50 00:04:16,470 --> 00:04:19,707 alitangaza CS kama mkusanyiko yangu, kuweka gov katika hatua hiyo nyuma yangu. 51 00:04:19,707 --> 00:04:22,290 Na hivyo sisi siyo kuweka nje katika Bila shaka hii kugeuka nyote 52 00:04:22,290 --> 00:04:25,780 katika CS majors au concentrators, lakini badala kukupa nafasi 53 00:04:25,780 --> 00:04:29,780 kwa hopefully kwenda zaidi ya dunia na ambayo wewe ni sasa ukoo 54 00:04:29,780 --> 00:04:33,660 na kuleta nyuma kutoka dunia hii ujuzi na maarifa na savvy 55 00:04:33,660 --> 00:04:36,220 kwamba unaweza kuomba kwa yako dunia mwenyewe, kama hiyo ni 56 00:04:36,220 --> 00:04:39,080 katika sanaa, sayansi ya jamii, sayansi ya asili, au zaidi. 57 00:04:39,080 --> 00:04:40,871 >> Hakika, kama wewe ni hisia kidogo intrepid 58 00:04:40,871 --> 00:04:43,250 juu ya kuwa katika chumba hiki achilia mbali katika darasa hili, 59 00:04:43,250 --> 00:04:47,560 kutambua kwamba kama historia ni ishara yoyote, 72% ya wewe 60 00:04:47,560 --> 00:04:49,802 hawajawahi kuchukuliwa shaka CS kabla. 61 00:04:49,802 --> 00:04:52,760 Hivyo ni kwa njia zote si kesi kwamba mwanafunzi ameketi upande wa kushoto 62 00:04:52,760 --> 00:04:56,850 au kulia au mbele au nyuma yenu anajua mbali zaidi kuhusu CS 63 00:04:56,850 --> 00:04:58,820 au programu hasa kuliko wewe. 64 00:04:58,820 --> 00:05:00,432 Hiyo si kweli kesi. 65 00:05:00,432 --> 00:05:02,140 Na hakika, kiasi cha muundo msaada 66 00:05:02,140 --> 00:05:04,600 kwamba tumekuwa kuanzisha katika hii Bila shaka katika kipindi cha miaka mingi 67 00:05:04,600 --> 00:05:08,840 imekuwa kwa hasa kwamba reason-- kwa kutoa juu ya njia panda kwamba bado exits 68 00:05:08,840 --> 00:05:11,640 tu kama usahihi mkubwa na tu kama juu kama ever-- 69 00:05:11,640 --> 00:05:14,860 lakini mteremko wa ambayo kuruhusu wanafunzi chini ya starehe na vizuri zaidi 70 00:05:14,860 --> 00:05:18,420 sawa ya kufanikiwa bila kujali wenye asili ya yake kabla. 71 00:05:18,420 --> 00:05:20,610 >> Hakika, nini hatimaye mambo katika darasa hili si 72 00:05:20,610 --> 00:05:22,830 sana ambapo wewe kuishia jamaa na wanafunzi wako 73 00:05:22,830 --> 00:05:26,000 lakini ambapo katika wiki 12 kuishia jamaa na wewe mwenyewe 74 00:05:26,000 --> 00:05:28,720 katika wiki sifuri, ambayo ni ambapo sisi ni hapa leo. 75 00:05:28,720 --> 00:05:32,315 >> Hakika na hii inaweza vizuri sana na pengine haina kuangalia kama Kigiriki 76 00:05:32,315 --> 00:05:32,940 kwa wengi wenu. 77 00:05:32,940 --> 00:05:35,200 Lakini wengine uhakika, kwamba huu na hivyo zaidi 78 00:05:35,200 --> 00:05:38,990 ni kwenda kuwa kabisa ndani yako kufahamu katika tu kidogo ya muda. 79 00:05:38,990 --> 00:05:41,410 >> Lakini leo hii, sisi kuzingatia baadhi ya kiwango cha juu ya mawazo 80 00:05:41,410 --> 00:05:43,822 kukupa ladha ya CS50 na sayansi ya kompyuta 81 00:05:43,822 --> 00:05:45,530 kwa maana ya kile wewe ni kusainiwa kwa ajili ya. 82 00:05:45,530 --> 00:05:48,000 Na hakika, sayansi ya kompyuta yapate distilled zaidi 83 00:05:48,000 --> 00:05:51,209 tu kama thinking-- computational kufikiri kama kompyuta, kama wewe. 84 00:05:51,209 --> 00:05:54,000 Na kuna mambo mengi tofauti viungo kwamba kwenda katika hiyo, 85 00:05:54,000 --> 00:05:56,240 lakini hebu kupendekeza tatu tu kwa leo. 86 00:05:56,240 --> 00:05:59,420 Kama lengo la daraja la hatimaye si kwa kufundisha wewe programu, 87 00:05:59,420 --> 00:06:03,022 si kufundisha C au PHP au SQL au idadi yoyote ya maneno 88 00:06:03,022 --> 00:06:04,730 na Vifupisho katika maelezo kozi ya, 89 00:06:04,730 --> 00:06:07,850 lakini badala ya kufundisha wewe kutatua matatizo kwa ufanisi zaidi 90 00:06:07,850 --> 00:06:11,670 na kufikiri methodically zaidi na algorithmically zaidi, hivyo kusema. 91 00:06:11,670 --> 00:06:13,610 Hebu angalia hasa hii inamaanisha nini. 92 00:06:13,610 --> 00:06:17,000 >> Hivyo napenda kupendekeza kwamba kufikiri computationally majipu chini 93 00:06:17,000 --> 00:06:17,834 kwa kutatua matatizo. 94 00:06:17,834 --> 00:06:19,333 Je, unahitaji kutatua tatizo? 95 00:06:19,333 --> 00:06:21,470 Unahitaji pembejeo kama pembejeo kwa problem-- 96 00:06:21,470 --> 00:06:23,636 unahitaji pato, ambayo ni hopefully ufumbuzi, 97 00:06:23,636 --> 00:06:26,720 na kisha unahitaji mchakato kwa ambayo kutatua tatizo hilo, ambayo 98 00:06:26,720 --> 00:06:30,030 tutaweza kuwaita algorithm seti ya maelekezo kwa ajili ya kutatua tatizo fulani. 99 00:06:30,030 --> 00:06:33,340 >> Lakini kwanza, hebu kuzingatia kwanza na mwisho wa haya pembejeo na mazao. 100 00:06:33,340 --> 00:06:38,070 Kompyuta baada ya yote, inaonekana tu anaelewa zeros na ndio. 101 00:06:38,070 --> 00:06:39,299 Lakini jinsi gani kwamba uwezekano kuwa? 102 00:06:39,299 --> 00:06:42,090 Hata kama wewe si ukoo wakati wote na nini chini ya Hood, 103 00:06:42,090 --> 00:06:44,980 pengine angalau kusikia kwamba kompyuta kuelewa binary-- 104 00:06:44,980 --> 00:06:48,050 zeros tu na ones-- lakini jinsi gani wewe pengine kufanya kitu chochote kuvutia? 105 00:06:48,050 --> 00:06:49,960 >> Naam, moja ya kaulimbiu ya darasa ni kwenda 106 00:06:49,960 --> 00:06:53,293 kuwa hii layering-- ambapo leo, tutaweza kuchukua mtazamo wa haraka katika ngazi ya chini kabisa 107 00:06:53,293 --> 00:06:55,620 maelezo, lakini kwa kila kupita siku, ambapo sisi safu 108 00:06:55,620 --> 00:06:59,420 au abstract juu ya wale maelezo kwa kweli kutatua ngazi za juu 109 00:06:59,420 --> 00:07:01,080 matatizo ya riba na sisi. 110 00:07:01,080 --> 00:07:04,730 >> Hivyo hapa ni nini sisi tupate kuwaita binary-- na tu alfabeti ya 0 na 1. 111 00:07:04,730 --> 00:07:06,960 Lakini sisi binadamu ni zaidi ukoo na decimal. 112 00:07:06,960 --> 00:07:08,130 Desemba maana 10. 113 00:07:08,130 --> 00:07:09,070 Bi maana mbili. 114 00:07:09,070 --> 00:07:12,100 Na hivyo katika decimal mfumo, tuna tatu 10 115 00:07:12,100 --> 00:07:14,099 katika disposal-- yetu ya Bila shaka, sifuri kupitia tisa. 116 00:07:14,099 --> 00:07:16,140 Hivyo kama ukiangalia idadi kama hii, wengi wenu 117 00:07:16,140 --> 00:07:19,016 intuitively tu kufahamu kwamba ni 123. 118 00:07:19,016 --> 00:07:20,640 Kuna kitu ngumu kweli kweli juu ya hilo. 119 00:07:20,640 --> 00:07:22,452 Lakini ni kwa nini 123? 120 00:07:22,452 --> 00:07:24,660 Naam, kama wewe kufikiri nyuma daraja school-- au angalau 121 00:07:24,660 --> 00:07:26,410 njia Mimi kujifunza hii aina ya world-- wewe 122 00:07:26,410 --> 00:07:29,640 kukumbuka kwamba sisi kutibiwa hizi mambo katika nguzo, au maeneo. 123 00:07:29,640 --> 00:07:31,412 >> Hivyo tuna ndio nafasi ya juu ya haki. 124 00:07:31,412 --> 00:07:32,620 mamia mahali katikati. 125 00:07:32,620 --> 00:07:34,240 mamia mahali upande wa kushoto. 126 00:07:34,240 --> 00:07:36,980 Na kisha jinsi gani sisi kupata kutoka muundo huu symbols-- 127 00:07:36,980 --> 00:07:41,771 1 2 3-- kwa kiwango hiki juu wazo kwamba sisi kujua kama 123? 128 00:07:41,771 --> 00:07:43,461 Naam, ni baadhi tu ya hesabu rahisi. 129 00:07:43,461 --> 00:07:43,960 Haki? 130 00:07:43,960 --> 00:07:48,960 >> moja kuna kimsingi ina maana kutupa mara 100 1 plus mara 10 131 00:07:48,960 --> 00:07:50,410 2 plus 1 mara 3. 132 00:07:50,410 --> 00:07:53,430 Na bila shaka kama sisi kufanya nje math huko, ni 100 plus 20 133 00:07:53,430 --> 00:07:56,480 plus 3-- inayojulikana kama 123. 134 00:07:56,480 --> 00:07:58,820 >> Hivyo kama wewe ni juu ya ukurasa huo huo kama haki kwamba 135 00:07:58,820 --> 00:08:02,320 sasa na ni starehe na kinachojulikana mfumo decimal kama binadamu, 136 00:08:02,320 --> 00:08:05,750 ni kweli vizuri ndani upeo wako wa faraja 137 00:08:05,750 --> 00:08:07,220 kufikiria sasa mfumo binary. 138 00:08:07,220 --> 00:08:10,110 Kuchukua porini guess-- hii inawakilisha, katika ulimwengu wa kompyuta 139 00:08:10,110 --> 00:08:12,001 katika binary-- idadi gani? 140 00:08:12,001 --> 00:08:12,500 Sifuri. 141 00:08:12,500 --> 00:08:13,580 >> Lakini kwa nini ni kwamba? 142 00:08:13,580 --> 00:08:17,460 Naam, zinageuka kuwa nguzo au maeneo here-- wao siyo nguvu za 10. 143 00:08:17,460 --> 00:08:19,670 1, 10, 100, 1000, na kadhalika. 144 00:08:19,670 --> 00:08:21,890 Wao ni badala yake, kabisa tu, madaraka ya 2. 145 00:08:21,890 --> 00:08:25,400 Hivyo, 1, 2, 4, 8, 16, 32, na kadhalika. 146 00:08:25,400 --> 00:08:29,630 Na hivyo sasa sisi bila shaka kupata 0 hapa tu kwa sababu tuna mara 4 147 00:08:29,630 --> 00:08:34,510 0 plus 2 mara 0 plus 1 mara 0, ambayo bila shaka inatupa 0. 148 00:08:34,510 --> 00:08:37,399 >> Lakini jinsi gani mimi kwenda kuhusu anayewakilisha namba 1? 149 00:08:37,399 --> 00:08:39,440 Nini mfano wa zeros na ndio kuiwakilisha 150 00:08:39,440 --> 00:08:42,720 idadi sisi binadamu kujua kama 1? 151 00:08:42,720 --> 00:08:44,280 001. 152 00:08:44,280 --> 00:08:46,370 Na 2? 153 00:08:46,370 --> 00:08:47,480 010. 154 00:08:47,480 --> 00:08:49,760 >> Na sasa mfano anaanza kurudia. 155 00:08:49,760 --> 00:08:50,890 Sasa ni 011. 156 00:08:50,890 --> 00:08:54,310 Na tena, 0 fours, moja 2, moja 1. 157 00:08:54,310 --> 00:08:55,180 Hivyo 2 plus 1. 158 00:08:55,180 --> 00:08:56,140 Hiyo ni 3. 159 00:08:56,140 --> 00:08:59,069 >> Na sasa kuiwakilisha 4, sisi si tu mabadiliko hayo 0 kwa 1. 160 00:08:59,069 --> 00:09:01,360 Wewe aina ya kuwa na kubeba, hivyo kusema, na nambari 161 00:09:01,360 --> 00:09:03,700 kuanza flipping kuzunguka tu kama katika dunia decimal. 162 00:09:03,700 --> 00:09:04,670 >> Hivyo hii ni 4. 163 00:09:04,670 --> 00:09:05,410 Hii ni 5. 164 00:09:05,410 --> 00:09:06,330 Hii ni 6. 165 00:09:06,330 --> 00:09:07,580 Hii ni 7. 166 00:09:07,580 --> 00:09:09,720 Na hivyo tumekuwa kuhesabiwa kama juu kama 7. 167 00:09:09,720 --> 00:09:12,400 >> Sasa wote sisi tu haja ni zaidi a bits-- zaidi zero na mtu. 168 00:09:12,400 --> 00:09:15,700 Na hakika "bits", kama wameweza aliposikia hayo term-- binary tarakimu. 169 00:09:15,700 --> 00:09:17,470 Kidogo ni wapi kwamba linatokana na. 170 00:09:17,470 --> 00:09:20,190 Na hivyo kama tunataka kuwakilisha idadi kubwa, tunahitaji bits zaidi. 171 00:09:20,190 --> 00:09:24,360 Lakini hebu kuondokana na slides sasa kwa kitu kidogo zaidi halisi. 172 00:09:24,360 --> 00:09:27,540 Tuseme kwamba tunataka kweli kuwakilisha jambo hili. 173 00:09:27,540 --> 00:09:31,790 >> Naam hebu tuangalie sasa katika maandamano kidogo. 174 00:09:31,790 --> 00:09:35,270 Hivyo hii ni mtandao msingi maombi kuwa moja ya CS50 ya mwenyewe, Michael G, 175 00:09:35,270 --> 00:09:38,160 kuweka pamoja hii majira ya kusaidia sisi elucidate hasa wazo hili. 176 00:09:38,160 --> 00:09:40,420 Na je mtu kama kujitosa juu ya hatua 177 00:09:40,420 --> 00:09:42,915 mbele ya wanafunzi wenzao yake yote? 178 00:09:42,915 --> 00:09:43,790 Haki pale mbele. 179 00:09:43,790 --> 00:09:45,660 Kuja juu juu. 180 00:09:45,660 --> 00:09:48,350 >> Wewe kuwa vizuri kwenye kamera na internet. 181 00:09:48,350 --> 00:09:50,930 182 00:09:50,930 --> 00:09:52,450 Oh, haki hapa. 183 00:09:52,450 --> 00:09:52,950 SAWA. 184 00:09:52,950 --> 00:09:53,740 Tuko OK. 185 00:09:53,740 --> 00:09:54,240 Sawa. 186 00:09:54,240 --> 00:09:54,740 Kuja juu juu. 187 00:09:54,740 --> 00:09:56,150 Jina lako nani? 188 00:09:56,150 --> 00:09:58,550 Emily kuja juu juu. 189 00:09:58,550 --> 00:09:59,410 Hivyo hii ni Emily. 190 00:09:59,410 --> 00:10:00,840 mwaka Je, ni wewe? 191 00:10:00,840 --> 00:10:01,660 >> Freshman. 192 00:10:01,660 --> 00:10:02,810 >> Emily, vyema kukutana na wewe. 193 00:10:02,810 --> 00:10:03,310 David. 194 00:10:03,310 --> 00:10:03,810 >> Sawa. 195 00:10:03,810 --> 00:10:06,120 Hivyo up kwenye screen hapa, tuna screen hii kugusa 196 00:10:06,120 --> 00:10:08,425 ambayo ni kwenda kuruhusu sisi kweli kuingiliana na mpango huu, 197 00:10:08,425 --> 00:10:09,265 na ni tu browser. 198 00:10:09,265 --> 00:10:11,390 Ni Chrome full kupimwa kwa wakati huu, lakini ni 199 00:10:11,390 --> 00:10:14,030 wamekuwa iliyowekwa na Michael kwa kujibu kwa njia ambayo inaruhusu 200 00:10:14,030 --> 00:10:15,970 sisi kucheza karibu na tatu mapacha. 201 00:10:15,970 --> 00:10:20,220 >> Hivyo kwa mfano, hapa tuna si tatu lakini nane zeros bits-- na ndio. 202 00:10:20,220 --> 00:10:22,000 Hivi sasa, tuko kuangalia idadi 0. 203 00:10:22,000 --> 00:10:25,150 Na hakika, zeros zote nane katika decimal ina maana zero. 204 00:10:25,150 --> 00:10:26,900 Hivyo hiyo ni yote yale ambayo ni kuwa aligusia saa hapa. 205 00:10:26,900 --> 00:10:29,395 >> Hivyo kama wewe alitaka kuwakilisha idadi 8, 206 00:10:29,395 --> 00:10:31,520 nini mfano wa zeros na wale ambao unataka? 207 00:10:31,520 --> 00:10:35,160 Unaweza tu bomba juu au chini au namba wenyewe. 208 00:10:35,160 --> 00:10:35,660 Sawa. 209 00:10:35,660 --> 00:10:37,659 Hivyo kwamba bila shaka ni 8, kama unaweza kuona huko. 210 00:10:37,659 --> 00:10:41,260 Na kama sisi alitaka je 16, tunafanya nini? 211 00:10:41,260 --> 00:10:42,701 >> Yep, tu kugusa tena. 212 00:10:42,701 --> 00:10:43,200 16. 213 00:10:43,200 --> 00:10:43,870 Sawa. 214 00:10:43,870 --> 00:10:46,522 Hivyo hii yote ni mzuri na mwema, bado ni kiwango cha chini sana. 215 00:10:46,522 --> 00:10:48,230 Tunahitaji njia katika ulimwengu wa kweli kwa Emily 216 00:10:48,230 --> 00:10:50,550 ya alimwakilisha mambo haya. 217 00:10:50,550 --> 00:10:54,230 Na hivyo tuseme kwamba sisi kugeuka hizi zeros na ndio, ambayo ni sana 218 00:10:54,230 --> 00:10:55,980 dhana, katika balbu halisi mwanga. 219 00:10:55,980 --> 00:10:56,480 Haki? 220 00:10:56,480 --> 00:10:59,540 >> kompyuta ni kimwili, mitambo, umeme kifaa. 221 00:10:59,540 --> 00:11:02,220 Na pembejeo zake angalau kama kuziba katika au malipo it-- 222 00:11:02,220 --> 00:11:05,090 ni kuwa na nguvu ya betri na elektroni inapita ndani na nje. 223 00:11:05,090 --> 00:11:08,150 >> Hivyo sasa, kwa nini sio sisi kuacha kufikiri kuhusu bits kama zeros na ndio, 224 00:11:08,150 --> 00:11:10,470 lakini kitu zaidi ya kimwili kama balbu mwanga hapa. 225 00:11:10,470 --> 00:11:13,815 Na kama Dan Armendáriz inaweza kujiunga na me kwa ajili tu moment-- kuja juu up-- 226 00:11:13,815 --> 00:11:15,440 tunakwenda foleni hadi maombi. 227 00:11:15,440 --> 00:11:15,940 >> Kuja juu juu, Emily. 228 00:11:15,940 --> 00:11:18,270 Sorry hii ni zaidi Awkward demo kwa ajili yenu milele. 229 00:11:18,270 --> 00:11:20,330 Kuja juu juu hapa. 230 00:11:20,330 --> 00:11:22,080 Tunakwenda foleni juu na shukrani kwa Dan 231 00:11:22,080 --> 00:11:25,300 Armendáriz, mwanachama mwingine wa wafanyakazi wetu, maombi inayojulikana kama bulb mapacha. 232 00:11:25,300 --> 00:11:28,070 >> Hivyo nini sisi hapa ni maombi iPad 233 00:11:28,070 --> 00:11:31,970 ambayo ina user zifuatazo interface juu ya screen kwa Emily. 234 00:11:31,970 --> 00:11:35,400 Ni tu got huo halisi UI kimsingi hiyo ni zaidi ya hapo. 235 00:11:35,400 --> 00:11:39,220 Na kama wewe sasa wanataka kuwakilisha idadi, wanasema 8, 236 00:11:39,220 --> 00:11:42,094 jinsi gani unaweza kwenda juu ya kufanya noticing hii katika haki, 237 00:11:42,094 --> 00:11:43,510 balbu mwanga kwamba sisi hapa? 238 00:11:43,510 --> 00:11:46,576 239 00:11:46,576 --> 00:11:47,620 Ah-ha. 240 00:11:47,620 --> 00:11:48,290 Kichawi. 241 00:11:48,290 --> 00:11:51,830 Hivyo kama tunataka sasa upande huu katika kitu kidogo changamoto zaidi, 242 00:11:51,830 --> 00:11:58,100 na hebu kwenda mbele na kuchukua random idadi kama idadi 50 hapa. 243 00:11:58,100 --> 00:11:59,015 Pembejeo hii. 244 00:11:59,015 --> 00:12:01,640 Na kama unaweza sasa kuwa changamoto kuja na idadi 50, 245 00:12:01,640 --> 00:12:04,268 tutaweza kuwa tuzo fabulous kwa ajili yenu. 246 00:12:04,268 --> 00:12:06,144 >> EMILY: OK. 247 00:12:06,144 --> 00:12:08,692 Mungu wangu. 248 00:12:08,692 --> 00:12:10,650 DAVID Malan: Hesabu ni kweli ngumu mbele 249 00:12:10,650 --> 00:12:12,860 ya mamia ya wanafunzi wako. 250 00:12:12,860 --> 00:12:16,260 Lakini 50 imekuwa jibu hapa. 251 00:12:16,260 --> 00:12:18,132 >> [Makofi] 252 00:12:18,132 --> 00:12:21,875 >> Na hivyo sasa, hii ni maana ya kuwa demonstrative kwa Emily. 253 00:12:21,875 --> 00:12:24,315 Hivyo, katika hapa, ni baadhi ya mwanga balbu kabisa kama haya, 254 00:12:24,315 --> 00:12:26,190 lakini ni kweli kidogo magnetic bidragen. 255 00:12:26,190 --> 00:12:28,570 Na nini baridi kuhusu haya na sababu sisi kuzitumia katika CS50 256 00:12:28,570 --> 00:12:31,640 ni kwamba wanaunga mkono kitu kinachoitwa API-- programu ya maombi 257 00:12:31,640 --> 00:12:34,681 interface, ambayo ni njia tu dhana ya kusema kwamba kile moja ya wafanyakazi wetu 258 00:12:34,681 --> 00:12:37,284 hakuwa juu ya jua ilikuwa kujenga maombi kutumika hapa 259 00:12:37,284 --> 00:12:39,700 kwamba mazungumzo juu ya mtandao kwa balbu mwanga zaidi ya hapa, 260 00:12:39,700 --> 00:12:41,810 ambayo ni wirelessly kushikamana na kifaa kingine. 261 00:12:41,810 --> 00:12:43,912 Lakini hii sasa ni chaguo kwa ajili ya miradi ya mwisho. 262 00:12:43,912 --> 00:12:46,370 Na hivyo Emily, kama wewe ungekuwa hivyo kama, mwishoni mwa muhula, 263 00:12:46,370 --> 00:12:48,703 unaweza kupamba Dorm chumba yako katika huo huo na wale. 264 00:12:48,703 --> 00:12:50,376 Asante kwa Emily vilevile. 265 00:12:50,376 --> 00:12:53,244 >> [Makofi] 266 00:12:53,244 --> 00:12:56,590 267 00:12:56,590 --> 00:13:00,055 >> Lakini sasa, hebu kurejea usikivu wetu kwa nini 268 00:13:00,055 --> 00:13:03,180 ujumbe kwamba anaweza kuwa inaonekana kama, na ni kitu kidogo kama hii. 269 00:13:03,180 --> 00:13:05,320 Kwa kweli, hii ni mfano kama teaser 270 00:13:05,320 --> 00:13:08,400 ya nini kuja ya nini aitwaye ombi API. 271 00:13:08,400 --> 00:13:11,409 Na hivyo kile sisi hapa ni tu hasa aina ya ujumbe 272 00:13:11,409 --> 00:13:13,200 kwamba baada ya wiki chache wakati katika CS50, utasikia 273 00:13:13,200 --> 00:13:16,590 kuwa na uwezo wa kutuma kwa kitu haki ukoo kama kwamba kwa kweli 274 00:13:16,590 --> 00:13:18,100 kurejea kwao na mbali. 275 00:13:18,100 --> 00:13:19,350 Lakini hii yote ni mzuri na mwema. 276 00:13:19,350 --> 00:13:19,850 Haki? 277 00:13:19,850 --> 00:13:22,710 Tuna mfano wa akili hopefully kwa anayewakilisha idadi na 278 00:13:22,710 --> 00:13:23,660 zero na mtu. 279 00:13:23,660 --> 00:13:26,290 Na kutoka zeros na ndio, tunaweza kupata idadi kubwa kama 50, 280 00:13:26,290 --> 00:13:29,460 kama Emily tu alifanya, au sisi unaweza hoja juu na kwamba. 281 00:13:29,460 --> 00:13:32,160 Na mimi kudai kwamba tunaweza kuwakilisha mambo kama barua vilevile. 282 00:13:32,160 --> 00:13:32,660 Haki? 283 00:13:32,660 --> 00:13:35,360 >> Kompyuta ni mbali zaidi kuvutia zaidi kuliko idadi tu. 284 00:13:35,360 --> 00:13:37,340 Na hivyo jinsi gani unaweza kwenda kuhusu anayewakilisha maneno 285 00:13:37,340 --> 00:13:39,420 juu ya screen au barua pepe au insha au kama? 286 00:13:39,420 --> 00:13:43,170 Naam, ni zamu nje kwamba kompyuta tu abstract juu ya kiwango cha chini hawa 287 00:13:43,170 --> 00:13:47,380 maelezo, na binadamu baadhi ya wakati uliopita, alikuja juu na holela, lakini thabiti, 288 00:13:47,380 --> 00:13:51,710 ramani ya namba kwa letters-- hivyo kwamba wakati wowote unaweza kuona herufi 289 00:13:51,710 --> 00:13:54,170 kwenye kompyuta yako screen, ni tabia mbaya nini 290 00:13:54,170 --> 00:13:57,370 chini ya kofia ni mfano wa zeros na ndio 291 00:13:57,370 --> 00:14:00,650 kwamba kuwakilisha idadi, per chati hii, 65. 292 00:14:00,650 --> 00:14:02,830 >> Na zaidi kimwili ndani ya kompyuta yako, 293 00:14:02,830 --> 00:14:06,450 ni mamilioni ya mambo kuitwa transistors-- days-- haya ambayo 294 00:14:06,450 --> 00:14:10,190 ni tu swichi kama wewe, mambo ambayo yanaweza kwenda na mbali na hivyo kufikiria. 295 00:14:10,190 --> 00:14:14,130 Si nane ya hizi kubwa balbu mwanga lakini mamilioni ya hayo vidogo mwanga kidogo 296 00:14:14,130 --> 00:14:17,490 balbu, au swichi au transistors, ambayo inaweza kugeuka na mbali 297 00:14:17,490 --> 00:14:19,170 kulingana na jinsi wewe mpango yao. 298 00:14:19,170 --> 00:14:22,120 Na hivyo sasa tuna njia ya anayewakilisha barua vilevile. 299 00:14:22,120 --> 00:14:25,300 >> Kwa kweli, kama ningekuwa kutumia hii ramani hapa na kujaribu kweli 300 00:14:25,300 --> 00:14:28,731 Spell kitu nje, sisi ili kuangalia katika muundo huu wa tatu decimal 301 00:14:28,731 --> 00:14:29,230 sasa hivi. 302 00:14:29,230 --> 00:14:31,354 Hivyo sisi siyo kwenda hata kuzingatia binary tena. 303 00:14:31,354 --> 00:14:35,910 Hebu tu kufikiria haya kama idadi decimal 72, 73, 33. 304 00:14:35,910 --> 00:14:38,044 Lakini nini inaweza hii kuwakilisha? 305 00:14:38,044 --> 00:14:39,960 Mtu yeyote kuwa kutosha kumbukumbu ya picha 306 00:14:39,960 --> 00:14:43,060 kujua nini yameandikwa juu ya screen hapa? 307 00:14:43,060 --> 00:14:43,560 Yeah chache. 308 00:14:43,560 --> 00:14:44,190 Hivyo hi. 309 00:14:44,190 --> 00:14:48,330 H-I na kisha kumweka Moderators, ambayo ilikuwa si kweli juu ya screen. 310 00:14:48,330 --> 00:14:51,060 Lakini kwa kweli kuna ramani kwa kila barua kwa kila idadi 311 00:14:51,060 --> 00:14:53,340 kwamba unaweza kutaka aina kwenye keyboard yako. 312 00:14:53,340 --> 00:14:55,430 >> Lakini idadi huna kuwakilisha barua tu. 313 00:14:55,430 --> 00:14:55,930 Haki? 314 00:14:55,930 --> 00:14:59,570 Sote tunajua kuhusu picha na picha na mafaili ya redio 315 00:14:59,570 --> 00:15:00,870 na mafaili video na kadhalika. 316 00:15:00,870 --> 00:15:03,580 Hivyo ni wazi tunaweza kuwakilisha kiwango cha mambo ya juu bado. 317 00:15:03,580 --> 00:15:06,920 Na hivyo kile kompyuta gani ni tu kuchagua 318 00:15:06,920 --> 00:15:11,240 kutafsiri chati ya ndio zero tofauti kulingana na mazingira. 319 00:15:11,240 --> 00:15:13,130 >> Kama wewe bonyeza mara mbili Microsoft Word icon, 320 00:15:13,130 --> 00:15:15,900 unaweza kuona maneno juu ya screen badala ya rangi na picha 321 00:15:15,900 --> 00:15:18,850 kwa sababu neno anajua kwamba hii ni insha kwamba umefanya kweli typed. 322 00:15:18,850 --> 00:15:21,510 Kama wewe badala click mara mbili juu ya JPEG au GIF au PNG, 323 00:15:21,510 --> 00:15:27,070 ni kufungua na ni mfano kwa sababu PNG au docx au chochote file 324 00:15:27,070 --> 00:15:30,450 ugani ni na chochote programu unatumia anajua kutafsiri 325 00:15:30,450 --> 00:15:34,420 mfano wa zeros na ndio tofauti kulingana na kile madhumuni yake katika maisha ni. 326 00:15:34,420 --> 00:15:37,330 >> Hivyo kwa mfano, hii huo mlolongo wa idadi 327 00:15:37,330 --> 00:15:41,250 wanaweza kuwakilisha kiasi gani nyekundu kufanya wewe wanataka, ni kiasi gani kijani Unataka, 328 00:15:41,250 --> 00:15:42,810 na kiasi gani bluu kufanya unataka. 329 00:15:42,810 --> 00:15:47,490 Na hakika, kama wameweza milele kusikia RGB-- hivyo tu nyekundu kijani bluu. 330 00:15:47,490 --> 00:15:51,380 Na hivyo kama mimi kuona idadi kama, hii nipe 72 nyekundu, nipe 73 kijani, 331 00:15:51,380 --> 00:15:56,910 na 33 bluu, hii ni jinsi gani kompyuta kwa kutumia tatu ka ambapo 332 00:15:56,910 --> 00:16:01,470 Byte ni bits nane au 24 bits-- kitawakilisha kivuli pretty nasty 333 00:16:01,470 --> 00:16:03,660 ya kahawia au njano hapa. 334 00:16:03,660 --> 00:16:07,500 Na katika mazingira tofauti, naweza wale halisi chati hiyo katika zeros na ndio 335 00:16:07,500 --> 00:16:10,780 maana kitu kabisa tofauti pia. 336 00:16:10,780 --> 00:16:13,899 >> Hivyo tuna sasa njia ya anayewakilisha zeros information-- na ndio. 337 00:16:13,899 --> 00:16:15,190 Juu ya kwamba, sisi kupata barua. 338 00:16:15,190 --> 00:16:16,860 Juu ya kwamba, tuweze kupata rangi. 339 00:16:16,860 --> 00:16:19,730 Na hebu kudhani kwa leo tuweze kupata redio na video 340 00:16:19,730 --> 00:16:22,590 na mambo mengi zaidi kisasa kuliko hiyo. 341 00:16:22,590 --> 00:16:25,370 >> Lakini sasa hebu fikiria jinsi ya kutumia pembejeo wale 342 00:16:25,370 --> 00:16:27,390 na kuzalisha wale matokeo sasa kwamba tuna 343 00:16:27,390 --> 00:16:29,830 njia za kuwasilisha taarifa hiyo. 344 00:16:29,830 --> 00:16:31,820 Naam, tunahitaji kitu aitwaye algorithm. 345 00:16:31,820 --> 00:16:34,320 Tena, seti ya maelekezo kwa ajili ya kutatua tatizo fulani 346 00:16:34,320 --> 00:16:37,580 hatua kwa step-- na sahihi zaidi, bora. 347 00:16:37,580 --> 00:16:42,090 >> Na hivyo mfano na ambayo binadamu ni admittedly chini ya ukoo siku hizi, 348 00:16:42,090 --> 00:16:44,300 lakini hata hivyo bado ni na sisi katika programu, 349 00:16:44,300 --> 00:16:47,490 ni mchakato wa kuangalia up mtu katika kitabu cha simu. 350 00:16:47,490 --> 00:16:51,690 >> Sasa, chache na chache folks kujua kila Mwaka gani masalio hii kwa kweli ni hapa. 351 00:16:51,690 --> 00:16:53,470 Lakini nyuma katika siku yangu, hii ilikuwa kitabu cha simu 352 00:16:53,470 --> 00:16:57,266 na maelfu ya kurasa na idadi na majina ya watu kutoka kupitia Z. 353 00:16:57,266 --> 00:17:00,390 Na hata kama sisi ni aina ya cheating a bit-- hii ni zaidi ya kurasa njano. 354 00:17:00,390 --> 00:17:01,920 Pia kulikuwa na nyeupe kurasa wakati huo, ambayo 355 00:17:01,920 --> 00:17:04,720 alikuwa wote wa majina hayo na idadi ya binadamu halisi. 356 00:17:04,720 --> 00:17:07,970 >> Na kama mimi alitaka kuangalia mtu up katika kitabu cha simu kama leo hii, bila shaka, 357 00:17:07,970 --> 00:17:11,010 Mimi tu aina katika michache ya kwanza wahusika wa jina lake, 358 00:17:11,010 --> 00:17:13,480 na simu yangu imegundua kwamba habari. 359 00:17:13,480 --> 00:17:15,970 Lakini utaratibu ambao yako iPhone au Android simu 360 00:17:15,970 --> 00:17:18,730 au chochote ni kweli kutafuta mtu katika mawasiliano orodha yako 361 00:17:18,730 --> 00:17:22,099 ni kufanana na kile sisi binadamu pengine wamefanya kwa muda fulani. 362 00:17:22,099 --> 00:17:24,260 >> Sasa mimi naweza kuchukua hii tatizo, kama wewe, 363 00:17:24,260 --> 00:17:26,220 na pembejeo hapa si zeros na ndio. 364 00:17:26,220 --> 00:17:28,730 Wao ni pages-- kama, hebu sema kurasa 1,000. 365 00:17:28,730 --> 00:17:32,650 Na kama mimi alitaka kuangalia up mtu kama Mike Smith katika kitabu hiki simu, 366 00:17:32,650 --> 00:17:35,570 Mimi naweza kuanza mwanzoni na kuona kwamba mimi niko katika A kifungu cha 367 00:17:35,570 --> 00:17:38,300 na kisha kugeuka ukurasa mmoja muda, kuangalia na kuangalia 368 00:17:38,300 --> 00:17:42,820 kama mimi kufanya kwa B na C na D's na kadhalika kwa Mike Smith. 369 00:17:42,820 --> 00:17:46,000 Smith kuanzia na S, mimi itabidi hopefully hatimaye kumpata. 370 00:17:46,000 --> 00:17:50,090 >> Ni algorithm hii kwamba process-- sahihi? 371 00:17:50,090 --> 00:17:50,590 Yeah. 372 00:17:50,590 --> 00:17:51,610 Ni sahihi. 373 00:17:51,610 --> 00:17:57,040 Mimi utapata Mike kama yeye ni katika hapa, lakini nini caveat kwamba unaweza kutoa. 374 00:17:57,040 --> 00:17:57,541 Ni mwepesi. 375 00:17:57,541 --> 00:17:58,040 Haki? 376 00:17:58,040 --> 00:18:00,975 Najua Mike S ni aina ya kuelekea mwisho nusu ya kitabu cha simu. 377 00:18:00,975 --> 00:18:02,766 Kwa nini heck mimi kuanzia mwanzoni 378 00:18:02,766 --> 00:18:04,349 na kwenda ukurasa kwa ukurasa kwa ukurasa. 379 00:18:04,349 --> 00:18:06,890 Hivyo bila shaka, mimi naweza flip ni karibu na kuanza kutoka nyuma, 380 00:18:06,890 --> 00:18:08,973 lakini hiyo ni kwenda kupata me there kwa kiwango hicho, 381 00:18:08,973 --> 00:18:10,930 kama wewe willl-- ukurasa baada ukurasa baada ya ukurasa. 382 00:18:10,930 --> 00:18:14,190 Na si kwenda kufanya kazi kama nataka kutafuta mtu mwingine ambaye 383 00:18:14,190 --> 00:18:15,880 jina linatokana mapema katika alfabeti. 384 00:18:15,880 --> 00:18:17,240 >> Basi nini kama mimi kufanya nini mimi kujifunza katika shule ya daraja, 385 00:18:17,240 --> 00:18:19,205 tena, kufanya mambo si na ndio lakini wawili-wawili. 386 00:18:19,205 --> 00:18:23,060 Hivyo 2, 4, 6, 8, 10, 12, na kadhalika. 387 00:18:23,060 --> 00:18:23,740 Ni kwamba ni sahihi? 388 00:18:23,740 --> 00:18:27,030 389 00:18:27,030 --> 00:18:27,560 Hakuna 390 00:18:27,560 --> 00:18:28,830 Ni aina ya sahihi. 391 00:18:28,830 --> 00:18:33,210 Lakini baadhi yenu ambao walikuwa wananung'unika hakuna, ambapo ni tatizo, au mdudu, 392 00:18:33,210 --> 00:18:34,240 makosa hivyo kusema. 393 00:18:34,240 --> 00:18:34,580 Yeah. 394 00:18:34,580 --> 00:18:36,570 >> STUDENT: Unaweza ruka juu ya kuingia haki. 395 00:18:36,570 --> 00:18:37,320 >> DAVID Malan: Yeah. 396 00:18:37,320 --> 00:18:40,340 Nipate ruka juu Mike Smith ni kwa sababu nimekuwa kuchukuliwa kurasa mbili kwa mara moja 397 00:18:40,340 --> 00:18:43,190 na yeye tu hutokea kwa kuwa ipo kati ya kurasa hizo mbili. 398 00:18:43,190 --> 00:18:46,500 Nipate kutambua kwamba Mimi nina juu ya kwa T kifungu cha 399 00:18:46,500 --> 00:18:48,690 wasiukute Mike Smith bado. 400 00:18:48,690 --> 00:18:50,820 >> Na hivyo kile inaweza fasta kuna kuwa? 401 00:18:50,820 --> 00:18:52,709 Naam, kama mimi kufanya kugonga Ts katika kitabu cha simu, 402 00:18:52,709 --> 00:18:54,500 Nipate haja ya mara mbili kuunga ukurasa mmoja au hivyo. 403 00:18:54,500 --> 00:18:56,830 Hivyo ni fixable, lakini siyo kabisa kama rahisi 404 00:18:56,830 --> 00:18:59,170 kama tu kwenda kwa wawili kuharakisha utendaji wangu. 405 00:18:59,170 --> 00:18:59,680 Lakini nini? 406 00:18:59,680 --> 00:19:00,180 Kuja juu. 407 00:19:00,180 --> 00:19:03,530 Je, ni yale ambayo wanadamu wengi ni kwenda cha kufanya na aina hii ya kitabu cha simu? 408 00:19:03,530 --> 00:19:04,696 Wewe ni kupewa kitabu cha simu. 409 00:19:04,696 --> 00:19:06,280 Unafanya nini? 410 00:19:06,280 --> 00:19:06,922 >> Nini kile? 411 00:19:06,922 --> 00:19:07,630 Kwenda katikati. 412 00:19:07,630 --> 00:19:10,620 Hivyo nikasikia kwenda katikati, na mimi kupata mwenyewe takribani katika M sehemu, 413 00:19:10,620 --> 00:19:11,120 hivyo kusema. 414 00:19:11,120 --> 00:19:12,670 Na sasa nini mimi nataka kufanya? 415 00:19:12,670 --> 00:19:14,077 Kazi nzuri. 416 00:19:14,077 --> 00:19:14,785 Jina lako nani? 417 00:19:14,785 --> 00:19:15,350 >> JAMES: James. 418 00:19:15,350 --> 00:19:15,890 >> DAVID Malan: James, sawa. 419 00:19:15,890 --> 00:19:16,829 Je, nini baada ya hapo? 420 00:19:16,829 --> 00:19:18,620 JAMES: Unaweza kwenda katika nusu ambayo ina S ya. 421 00:19:18,620 --> 00:19:18,740 DAVID Malan: zote haki. 422 00:19:18,740 --> 00:19:20,910 Mimi nina kwenda katika nusu kwamba ina S ndani yake kwa sababu, tena, 423 00:19:20,910 --> 00:19:22,920 stipulation hapa ilikuwa kwamba jambo hili ni Iliyopangwa. 424 00:19:22,920 --> 00:19:25,461 Ni pretty haina maana 1,000 kurasa kama Verizon haina kweli 425 00:19:25,461 --> 00:19:27,339 kutatua mambo haya kwa ajili yetu kupitia Z. 426 00:19:27,339 --> 00:19:30,130 Hivyo kama mimi kujua Mike pengine ni katika mwisho nusu ya kitabu cha simu, 427 00:19:30,130 --> 00:19:31,536 Naweza sasa. 428 00:19:31,536 --> 00:19:33,388 >> [Anacheka] 429 00:19:33,388 --> 00:19:35,240 430 00:19:35,240 --> 00:19:37,391 >> Machozi tatizo katika nusu. 431 00:19:37,391 --> 00:19:38,615 >> [Makofi] 432 00:19:38,615 --> 00:19:39,115 433 00:19:39,115 --> 00:19:40,300 Asante. 434 00:19:40,300 --> 00:19:42,510 Machozi tatizo katika nusu. 435 00:19:42,510 --> 00:19:44,440 Kwamba alikuwa kweli real-- kwamba mapambano. 436 00:19:44,440 --> 00:19:47,050 Hivyo machozi kitabu cha simu katika nusu, na kuacha mwenyewe 437 00:19:47,050 --> 00:19:48,580 na kimsingi tatizo moja. 438 00:19:48,580 --> 00:19:50,060 Lakini bila shaka, nusu kama kubwa. 439 00:19:50,060 --> 00:19:52,550 Na kama mimi kufuata James Ushauri tena, na mimi kwenda hapa. 440 00:19:52,550 --> 00:19:54,400 Nasema, loo sasa niko katika T sehemu. 441 00:19:54,400 --> 00:19:56,460 >> Na hivyo bila shaka, mimi unaweza machozi kitabu cha simu 442 00:19:56,460 --> 00:19:59,660 katika nusu ya wakati mmoja zaidi, na kuacha me na tatizo hilo 443 00:19:59,660 --> 00:20:00,810 sasa robo ya kawaida. 444 00:20:00,810 --> 00:20:05,335 Hivyo nimekuwa wamekwenda kutoka 1,000 hadi 500 250 kwa 125 na kadhalika. 445 00:20:05,335 --> 00:20:07,350 Ni anahisi kama mimi nina kuchukua kuumwa kubwa nje 446 00:20:07,350 --> 00:20:10,615 ya tatizo hili na kila iteration, au kila hatua katika hilo. 447 00:20:10,615 --> 00:20:15,580 >> Na hakika, wakati mimi nina kwenda kutumia kutafuta Mike Smith katika mfano huu 448 00:20:15,580 --> 00:20:18,970 ni kiasi kidogo kwa sababu hatimaye mimi nina kwenda whittle hii kitabu pone chini 449 00:20:18,970 --> 00:20:20,192 kwa lone ukurasa mmoja tu. 450 00:20:20,192 --> 00:20:23,010 Na kama Mike ni juu ya ukurasa huo, mimi nina kwenda mbele na kumpa 451 00:20:23,010 --> 00:20:24,670 wito baada ya kupatikana kwake. 452 00:20:24,670 --> 00:20:27,030 >> Lakini tu jinsi bora zaidi ni kwamba algorithm 453 00:20:27,030 --> 00:20:29,690 kwamba kuthubutu kusema Intuitive algorithm kuliko wale sisi 454 00:20:29,690 --> 00:20:34,920 ilianza na ambayo tuko linear-- sana kushoto na right-- kwa kasi ya 1 au 2x? 455 00:20:34,920 --> 00:20:36,100 >> Naam, hebu njama hii. 456 00:20:36,100 --> 00:20:39,380 Hatuna wasiwasi sana kuhusu math au namba katika kesi hii hapa. 457 00:20:39,380 --> 00:20:40,550 Sisi tu kuangalia njama. 458 00:20:40,550 --> 00:20:43,600 Kadhalika x, au usawa mhimili, ni ukubwa wa problem-- 459 00:20:43,600 --> 00:20:44,700 jinsi kurasa nyingi ni pale. 460 00:20:44,700 --> 00:20:46,760 On y, au wima mhimili, ni muda kiasi gani 461 00:20:46,760 --> 00:20:48,218 ni kwenda kuchukua yangu ya kulitatua. 462 00:20:48,218 --> 00:20:50,760 Na labda hiyo ni wangapi ukurasa zamu, sekunde ngapi, 463 00:20:50,760 --> 00:20:52,370 jinsi wengi baadhi kitengo cha hatua. 464 00:20:52,370 --> 00:20:57,810 >> Na nimekuwa inayotolewa nyekundu mistari moja kwa moja hapa kwa sababu kama kila ukurasa ziada 465 00:20:57,810 --> 00:21:01,740 ya kitabu cha simu, mimi zinahitaji kufanya hatua moja ya ziada. 466 00:21:01,740 --> 00:21:03,680 Hivyo kama Verizon anaongeza moja zaidi ukurasa mwaka ujao, 467 00:21:03,680 --> 00:21:06,970 Nipate kuwa na flip zaidi ukurasa mmoja kupata mtu kama Mike Smith. 468 00:21:06,970 --> 00:21:11,340 >> Wakati huo huo, algorithm ya pili, ambayo Nilikwenda wawili-wawili, ni umbo moja. 469 00:21:11,340 --> 00:21:15,220 Bado ni linear sana, kushoto sana haki, kuchukua ka sawa kila wakati, 470 00:21:15,220 --> 00:21:16,900 lakini mteremko ni chini kidogo. 471 00:21:16,900 --> 00:21:23,590 >> Kwa mfano, ikiwa na ukubwa wa Tatizo walikuwa takribani hapa 472 00:21:23,590 --> 00:21:25,990 na mimi kutumika algorithm yangu ya kwanza, Mimi inaweza kuishia njia yote 473 00:21:25,990 --> 00:21:27,480 utafutaji juu ya mstari kwamba nyekundu. 474 00:21:27,480 --> 00:21:29,390 Lakini kama mimi badala yake kutumia kwa twosies mbinu, 475 00:21:29,390 --> 00:21:31,480 line njano unaonyesha kwa sababu ni ya chini, 476 00:21:31,480 --> 00:21:33,790 kwamba ni kwenda kuchukua me muda kidogo kutatua. 477 00:21:33,790 --> 00:21:37,400 >> Lakini nini sura ya tatu algorithm tena, arguably 478 00:21:37,400 --> 00:21:38,707 wengi Intuitive algorithm? 479 00:21:38,707 --> 00:21:40,540 Naam, inaonekana kidogo kitu kama hiki. 480 00:21:40,540 --> 00:21:43,480 Ni curved, au logarithmic, katika sura. 481 00:21:43,480 --> 00:21:46,510 Na hata kama ni kamwe aina ya kunasiliba nje, 482 00:21:46,510 --> 00:21:50,770 ni asymptotically inches juu na juu na juu lakini sana polepole 483 00:21:50,770 --> 00:21:52,129 dhidi ya kila kitu kingine. 484 00:21:52,129 --> 00:21:53,170 Na nini kuchukua? 485 00:21:53,170 --> 00:21:54,215 Naam, sisi kuiita logi n. 486 00:21:54,215 --> 00:21:55,820 Lakini ni nini kwamba kweli maana? 487 00:21:55,820 --> 00:21:58,580 Naam kama Verizon mara mbili idadi ya kurasa katika kitabu cha simu 488 00:21:58,580 --> 00:22:00,810 mwaka ujao kutoka 1,000 hadi 2,000. 489 00:22:00,810 --> 00:22:04,600 Jinsi hatua zaidi wengi ni yangu algorithm kwanza kwenda kuchukua? 490 00:22:04,600 --> 00:22:05,440 >> algorithm yangu ya kwanza. 491 00:22:05,440 --> 00:22:06,399 Labda 1,000 hatua zaidi. 492 00:22:06,399 --> 00:22:08,106 Kama wao mara mbili kitabu cha simu, mimi nina kwenda 493 00:22:08,106 --> 00:22:10,590 kuwa na flip kupitia mwingine 1,000 kurasa kupata Mike. 494 00:22:10,590 --> 00:22:13,240 Bila shaka, kama pili algorithm, labda 500 kwa sababu mimi nina 495 00:22:13,240 --> 00:22:14,610 kwenda mara mbili kwa haraka. 496 00:22:14,610 --> 00:22:18,380 >> Lakini kama Verizon maradufu idadi ya kurasa kati ya mwaka huu na ujao, 497 00:22:18,380 --> 00:22:21,650 na wa tatu yangu algorithm mgawanyiko na kushinda kwamba James mapendekezo, 498 00:22:21,650 --> 00:22:24,450 kwenda katika nusu na nusu na half-- hatua jinsi wengi zaidi mapenzi 499 00:22:24,450 --> 00:22:29,030 ni kuchukua yangu mwaka ujao kuwa na kitabu cha simu ya kawaida 2,000? 500 00:22:29,030 --> 00:22:29,670 Moja tu. 501 00:22:29,670 --> 00:22:34,110 Kwa sababu kwa bite moja, siwezi kuchukua, nje ya tatizo hilo, nusu ya kurasa 502 00:22:34,110 --> 00:22:34,694 mbali. 503 00:22:34,694 --> 00:22:37,860 Na kama unadhani kuhusu hili kidogo crazily now-- kama kitabu cha simu hana 504 00:22:37,860 --> 00:22:41,810 na 1,000 au 2000 ukurasa, lakini hebu sema bilioni 4 pages-- 505 00:22:41,810 --> 00:22:45,282 ni simu kubwa book-- jinsi mara nyingi au jinsi hatua nyingi 506 00:22:45,282 --> 00:22:47,740 ni kwenda kuchukua mimi kupata Mike Smith katika kitabu cha simu 507 00:22:47,740 --> 00:22:50,489 na kurasa bilioni 4. 508 00:22:50,489 --> 00:22:52,030 Unaweza aina ya kuanza kufanya math. 509 00:22:52,030 --> 00:22:52,200 Sawa. 510 00:22:52,200 --> 00:22:53,175 bilioni 4 kugawanywa na 2. 511 00:22:53,175 --> 00:22:54,550 Hivyo hiyo ni bilioni 2 kugawanywa na 1. 512 00:22:54,550 --> 00:22:55,510 Hiyo ni bilioni 1. 513 00:22:55,510 --> 00:22:56,410 Kisha nusu bilioni. 514 00:22:56,410 --> 00:22:59,940 Kisha 250-- hivyo unaweza kufanya hivyo tena na tena lakini si kwamba mara nyingi kabla ya 515 00:22:59,940 --> 00:23:01,020 kupata ukurasa mmoja. 516 00:23:01,020 --> 00:23:04,360 >> Na hakika, hata kama simu kitabu ni bilioni 4 kurasa muda mrefu 517 00:23:04,360 --> 00:23:08,340 au database wewe ni kutafuta ni bilioni 4 rekodi kwa muda mrefu, 518 00:23:08,340 --> 00:23:12,720 ni kwenda kuchukua wewe kutoa au kuchukua hatua 32 tu kupata Mike Smith. 519 00:23:12,720 --> 00:23:15,990 Na kama wewe mara mbili kitabu cha simu ijayo mwaka kutoka bilioni 4 kwa bilioni 8, 520 00:23:15,990 --> 00:23:19,010 hatua 33 badala ya 32 tu. 521 00:23:19,010 --> 00:23:21,100 >> Na hii ni ushahidi kwa moja ya mawazo 522 00:23:21,100 --> 00:23:24,100 tupate kukumbatia katika kompyuta sayansi kwa ujumla zaidi, ambayo 523 00:23:24,100 --> 00:23:26,760 ni fikra hii computational na inakaribia tatizo 524 00:23:26,760 --> 00:23:29,479 kusema ukweli kwa kutumia zana kutoka chombo yako tayari ukoo 525 00:23:29,479 --> 00:23:31,520 kit-- dunia yako halisi na ambayo wewe ni ukoo, 526 00:23:31,520 --> 00:23:34,730 lakini kuimarisha mawazo hayo kwa kweli kutatua matatizo. 527 00:23:34,730 --> 00:23:37,200 >> Lakini tunahitaji kurasimisha yetu ufumbuzi wa matatizo haya. 528 00:23:37,200 --> 00:23:40,200 Na hivyo basi mimi kuanzisha kwa muda kitu tunachoweza kukiita pseudocode. 529 00:23:40,200 --> 00:23:44,260 Mengi ya muhula, tutaweza kutumia kutumia halisi code kwa lugha kama C na PHP 530 00:23:44,260 --> 00:23:46,570 na JavaScript na SQL na kadhalika. 531 00:23:46,570 --> 00:23:49,000 >> Lakini kwa sasa, hebu tu kuangalia katika kitu haki angavu 532 00:23:49,000 --> 00:23:49,930 kama Kiingereza. 533 00:23:49,930 --> 00:23:52,490 Nipate distill kwamba algorithm ambayo 534 00:23:52,490 --> 00:23:54,650 Nimeona Mike katika hatua kama hii. 535 00:23:54,650 --> 00:23:55,760 >> Pick up kitabu cha simu 536 00:23:55,760 --> 00:23:57,121 >> Open katikati ya kitabu cha simu 537 00:23:57,121 --> 00:23:57,870 Angalia katika jina la 538 00:23:57,870 --> 00:23:59,290 Kama Mike ni miongoni mwa jina la 539 00:23:59,290 --> 00:24:00,450 Wito Mike 540 00:24:00,450 --> 00:24:02,290 Mwingine kama Smith ni mapema katika kitabu 541 00:24:02,290 --> 00:24:04,540 Open katikati ya kushoto nusu ya kitabu 542 00:24:04,540 --> 00:24:06,244 Mwingine kwenda kujipanga 3 543 00:24:06,244 --> 00:24:07,660 Mwingine kama Smith ni baadaye katika kitabu 544 00:24:07,660 --> 00:24:09,330 Open katikati ya nusu haki ya kitabu 545 00:24:09,330 --> 00:24:09,996 Kwenda kujipanga tatu 546 00:24:09,996 --> 00:24:10,720 kingine 547 00:24:10,720 --> 00:24:11,500 Kata tamaa 548 00:24:11,500 --> 00:24:15,360 Na kuna sifa chache sasa hiyo ambayo ni thamani ya kusema. 549 00:24:15,360 --> 00:24:18,370 Hivyo moja, mistari yote Nimekuwa yalionyesha katika njano 550 00:24:18,370 --> 00:24:21,430 tunakwenda kuanza wito kauli au kazi au taratibu. 551 00:24:21,430 --> 00:24:24,160 Wao ni vitendo tu kufanya huu, na kuna si 552 00:24:24,160 --> 00:24:26,400 kwamba tofauti zote mengi ya hayo. 553 00:24:26,400 --> 00:24:30,850 >> hatua ya pili hapa ingawa, ni haya conditions-- kama, mwingine, mwingine kama, mwingine. 554 00:24:30,850 --> 00:24:34,020 Na haya ndiyo inaitwa hali au matawi, na wao uko pointi uamuzi. 555 00:24:34,020 --> 00:24:36,780 Nao kuruhusu sisi kufanya kitu kwa masharti. 556 00:24:36,780 --> 00:24:39,650 >> Na kwa kweli, hebu kuchukua haraka tuangalie labda face-- ukoo 557 00:24:39,650 --> 00:24:43,380 tutaweza kumwita Bill-- na nini hali hizi hasa, 558 00:24:43,380 --> 00:24:45,670 jinsi haya inaweza kutumika. 559 00:24:45,670 --> 00:24:48,230 >> BILL GATES: Watu kufanya maamuzi kila siku. 560 00:24:48,230 --> 00:24:51,800 Kwa mfano, kabla ya kwenda nje wewe aina ya kuwa kama taarifa kwamba anasema, 561 00:24:51,800 --> 00:24:55,650 kama ni mvua, basi mimi Unahitaji kupata koti langu. 562 00:24:55,650 --> 00:25:00,990 >> Na kompyuta ni ajabu mara moja kuamua aina wale wa kauli 563 00:25:00,990 --> 00:25:06,450 waweze reliably nitafanya mambo hayo kwa kasi ya ajabu. 564 00:25:06,450 --> 00:25:12,470 Na hivyo programu ya kompyuta kweli ni kidogo ya math na baadhi 565 00:25:12,470 --> 00:25:16,890 kama kauli ambapo uamuzi anapata alifanya. 566 00:25:16,890 --> 00:25:19,432 >> DAVID Malan: Hivyo sasa hebu lengo juu ya lines-- chache tofauti 567 00:25:19,432 --> 00:25:21,140 wale nimekuwa yalionyesha katika njano hapa. 568 00:25:21,140 --> 00:25:23,890 Na ni zamu huko nje ni tofauti njia za kueleza wazo hili. 569 00:25:23,890 --> 00:25:28,550 Lakini intuitively nini mistari yetu 8 na 11 kwamba nimepata yalionyesha hapa nawaambia 570 00:25:28,550 --> 00:25:29,100 kufanya? 571 00:25:29,100 --> 00:25:33,081 Ndiyo, kwenda kujipanga 3, lakini kile tabia ni kwamba kweli inducing? 572 00:25:33,081 --> 00:25:35,580 Ni aina fulani ya kitanzi au mzunguko, na unaweza aina ya kuona. 573 00:25:35,580 --> 00:25:36,079 Haki? 574 00:25:36,079 --> 00:25:39,710 Kama kwenye mstari 8, wewe kwenda nyuma ya mstari 3, na kisha kugonga line 8 tena, 575 00:25:39,710 --> 00:25:42,700 unaweza kwenda nyuma ya mstari wa 3, nyuma ya mstari wa 3, nyuma ya kujipanga 3. 576 00:25:42,700 --> 00:25:44,530 Kuna aina hii ya mzunguko au kitanzi. 577 00:25:44,530 --> 00:25:47,177 Na hakika, hiyo ikiwa katika line 11 uwezekano vilevile. 578 00:25:47,177 --> 00:25:49,260 Na hii ni msingi programu kujenga vilevile. 579 00:25:49,260 --> 00:25:51,593 >> Unaweza si unataka tu kufanya kitu kwa kauli 580 00:25:51,593 --> 00:25:54,280 au kufanya kitu kwa masharti na hali au tawi. 581 00:25:54,280 --> 00:25:56,644 Unaweza kutaka kufanya kitu cyclically na kitanzi. 582 00:25:56,644 --> 00:25:59,810 Na tutaweza kuwa na mtu mwingine ambaye unaweza kuwa familiar-- tutaweza kumwita 583 00:25:59,810 --> 00:26:02,996 Mark-- kuelezea dhana hii hapa. 584 00:26:02,996 --> 00:26:04,870 Mark Zuckerberg: One Jambo kwamba kompyuta ni 585 00:26:04,870 --> 00:26:07,460 mzuri katika ni kurudia amri. 586 00:26:07,460 --> 00:26:09,510 Kama mtu, wewe Ningependa kupata kweli kuchoka kama wewe 587 00:26:09,510 --> 00:26:12,310 alikuwa na kufanya kitu kimoja kura ya mara katika mstari, 588 00:26:12,310 --> 00:26:16,230 lakini iliyokaa na unaweza kufanya kitu kimoja mamilioni au hata mabilioni ya mara 589 00:26:16,230 --> 00:26:18,930 na si kupata kuchoka na kuwa na uwezo kubeba kwamba nje vizuri. 590 00:26:18,930 --> 00:26:21,240 >> Hivyo kwa mfano, kama mimi kuwatakia kila mtu 591 00:26:21,240 --> 00:26:24,450 katika Picha furaha ya kuzaliwa na kuwapeleka email, 592 00:26:24,450 --> 00:26:27,037 inaweza kuchukua mimi zaidi kuliko karne ya kweli kuandika nje 593 00:26:27,037 --> 00:26:28,370 yote ya barua pepe wale kwa kila mtu. 594 00:26:28,370 --> 00:26:33,500 Lakini mistari na chache tu ya kificho, naweza kuwa na mfumo tuma barua pepe kwa kila mtu 595 00:26:33,500 --> 00:26:35,460 katika Picha wanaotaka nao furaha ya kuzaliwa. 596 00:26:35,460 --> 00:26:38,330 >> Hivyo kwamba ni nini loops ni na nini wao uko thamani na kitu 597 00:26:38,330 --> 00:26:40,076 kwamba kompyuta anaweza kufanya vizuri sana. 598 00:26:40,076 --> 00:26:43,109 >> DAVID Malan: Wengi shukrani kwa marafiki zetu katika code.org kwa ajili ya filamu hizo mbili. 599 00:26:43,109 --> 00:26:46,150 Na tu wiki iliyopita, unaweza kuwa na kuonekana kwamba Mark Zuckerberg na Facebook 600 00:26:46,150 --> 00:26:47,940 zilizowekwa tangazo hili, ambayo ni kwamba wao tu 601 00:26:47,940 --> 00:26:50,398 imepita muhimu hatua kwa mara ya kwanza kabisa. 602 00:26:50,398 --> 00:26:54,320 Watu bilioni 1 kutumika katika Picha siku moja, hasa Jumatatu iliyopita. 603 00:26:54,320 --> 00:26:58,650 Moja kwa binadamu saba Duniani inaonekana watumiaji katika Facebook. 604 00:26:58,650 --> 00:27:03,310 >> Naam, hii inaonekana fursa nzuri kuangalia nyuma juu ambapo Facebook ilianza, 605 00:27:03,310 --> 00:27:06,840 na sisi akaenda kwa njia ya CS50 ya mwenyewe nyaraka kwa sababu ni zamu nje mwaka 2005, 606 00:27:06,840 --> 00:27:10,020 Mark alitoa hotuba mgeni katika CS50. 607 00:27:10,020 --> 00:27:13,870 Utaona kwamba maadili ya uzalishaji hawakuwa kabisa nyuma moja basi 608 00:27:13,870 --> 00:27:16,110 katika suala la teknolojia inapatikana, na utasikia pia 609 00:27:16,110 --> 00:27:18,310 kuona kwamba uwepo ya hii hotuba mgeni 610 00:27:18,310 --> 00:27:22,470 haikuwa lazima pique maslahi ya mwanafunzi mwili, watangulizi yako, 611 00:27:22,470 --> 00:27:24,910 kama vile ni kuwa na miaka michache baadaye. 612 00:27:24,910 --> 00:27:27,902 >> Hivyo basi tuangalie katika Sayansi Center C. 613 00:27:27,902 --> 00:27:29,389 614 00:27:29,389 --> 00:27:31,014 SPIKA 2: Tafadhali kujiunga na mimi, na kuwakaribisha. 615 00:27:31,014 --> 00:27:33,374 616 00:27:33,374 --> 00:27:36,577 [Makofi] 617 00:27:36,577 --> 00:27:37,410 Mark Zuckerberg: Yo. 618 00:27:37,410 --> 00:27:37,900 Sawa. 619 00:27:37,900 --> 00:27:40,420 Cool hii ni mara ya kwanza nimekuwa milele wamekuwa na kushikilia moja ya mambo haya. 620 00:27:40,420 --> 00:27:42,336 Hivyo mimi nina kwenda tu ambatisha kweli haraka. 621 00:27:42,336 --> 00:27:54,354 622 00:27:54,354 --> 00:27:54,854 Sawa. 623 00:27:54,854 --> 00:27:57,314 Je, unaweza kusikia? 624 00:27:57,314 --> 00:27:58,298 Je, hii ni nzuri? 625 00:27:58,298 --> 00:28:00,684 Je, hii ni alijiinua wakati wote? 626 00:28:00,684 --> 00:28:01,184 Sawa. 627 00:28:01,184 --> 00:28:02,040 Tamu. 628 00:28:02,040 --> 00:28:06,860 Hivyo, hii ni kama moja ya nyakati wa kwanza Nimekuwa na hotuba katika Harvard, 629 00:28:06,860 --> 00:28:08,660 but-- 630 00:28:08,660 --> 00:28:12,510 >> DAVID Malan: Hivyo hatimaye Sayansi Center alifanya kuvuta video, 631 00:28:12,510 --> 00:28:15,110 lakini si kabla ya ukamataji huu excerpt ambapo Marko kuzungumza, 632 00:28:15,110 --> 00:28:18,230 ambayo yeye kujadiliwa yake roommate, Dustin, ambaye 633 00:28:18,230 --> 00:28:20,885 alitaka kukopesha mkono na hii tovuti inayoitwa Facebook.com 634 00:28:20,885 --> 00:28:24,540 na kubaini kuwa Mark ni kuhusu kutaja na programu languages-- 635 00:28:24,540 --> 00:28:27,290 mtu mmoja aitwaye Perl, moja aitwaye PHP-- kama yeye kujadili 636 00:28:27,290 --> 00:28:28,840 Asili ya mchango Dustin. 637 00:28:28,840 --> 00:28:31,499 638 00:28:31,499 --> 00:28:33,290 Mark Zuckerberg: Mimi kuanza mbio tovuti 639 00:28:33,290 --> 00:28:37,770 na ilizindua hiyo kwa Harvard mwezi Februari, 2004. 640 00:28:37,770 --> 00:28:39,540 Kwa hiyo mimi nadhani karibu miaka miwili iliyopita sasa. 641 00:28:39,540 --> 00:28:42,322 Na ndani ya wiki kadhaa, a watu elfu chache alikuwa saini up, 642 00:28:42,322 --> 00:28:45,280 na sisi kuanza kupata barua pepe baadhi kutoka kwa watu katika vyuo vingine kuuliza 643 00:28:45,280 --> 00:28:47,520 kwa sisi kuzindua ni katika shule zao. 644 00:28:47,520 --> 00:28:49,455 >> Na nilikuwa kuchukua 161 wakati huo. 645 00:28:49,455 --> 00:28:52,080 Hivyo mimi sijui kama wewe guys kujua sifa bila shaka kwamba, 646 00:28:52,080 --> 00:28:54,402 lakini ilikuwa ni aina ya nzito. 647 00:28:54,402 --> 00:28:57,110 Ilikuwa shaka kweli ni furaha, lakini hakuwa na kuondoka na muda mwingi 648 00:28:57,110 --> 00:28:59,260 kufanya kitu kingine chochote na Facebook. 649 00:28:59,260 --> 00:29:04,309 Hivyo roommate yangu Dustin, ambaye mimi nadhani alikuwa tu kumaliza CS50, ilikuwa kama, hey. 650 00:29:04,309 --> 00:29:05,100 Nataka kusaidia nje. 651 00:29:05,100 --> 00:29:08,760 Nataka kufanya upanuzi na kusaidia wewe kufikiri jinsi ya kufanya mambo ya ajabu. 652 00:29:08,760 --> 00:29:10,780 >> Hivyo mimi nilikuwa kama, hiyo ni pretty baridi, dude. 653 00:29:10,780 --> 00:29:13,130 Lakini wewe si kweli kujua yoyote PHP au kitu kama hicho. 654 00:29:13,130 --> 00:29:16,444 Hivyo mwishoni mwa wiki kwamba alikwenda nyumbani, kununua kitabu Perl for Dummies, 655 00:29:16,444 --> 00:29:17,860 akarudi na ilikuwa kama, sawa. 656 00:29:17,860 --> 00:29:18,940 Mimi niko tayari kwenda. 657 00:29:18,940 --> 00:29:23,010 >> Mimi nilikuwa kama, dude, tovuti Imeandikwa katika PHP si Perl, lakini hiyo ni cool. 658 00:29:23,010 --> 00:29:28,530 >> Hivyo yeye ilichukua PHP juu ya siku kama wachache kwa sababu mimi 659 00:29:28,530 --> 00:29:30,790 ahadi kwamba kama una background nzuri katika C, 660 00:29:30,790 --> 00:29:32,970 PHP ni jambo rahisi sana kuchukua. 661 00:29:32,970 --> 00:29:37,480 Naye aina tu ya alikwenda kazi. 662 00:29:37,480 --> 00:29:40,500 >> Kabla ya sisi kuangalia sasa katika ambapo bila shaka ni kwenda, 663 00:29:40,500 --> 00:29:43,047 naomba kukaribisha baadhi tu ya wafanyakazi SC50 ya juu kwa hatua. 664 00:29:43,047 --> 00:29:44,880 Baadhi yao ni ununuzi kozi yao wenyewe. 665 00:29:44,880 --> 00:29:48,390 Lakini kama wale TFS na CAS na shaka vichwa ambao ni hapa inaweza kuja juu juu 666 00:29:48,390 --> 00:29:50,230 na kujiunga na mimi kwa hodi haraka. 667 00:29:50,230 --> 00:29:54,670 >> Naomba kuanzisha hasa, Hanna, Maria, Daven, na Rob, 668 00:29:54,670 --> 00:29:59,666 Bila shaka CS50 anaongoza hapa katika Cambridge. 669 00:29:59,666 --> 00:30:02,106 >> [Makofi] 670 00:30:02,106 --> 00:30:07,490 671 00:30:07,490 --> 00:30:11,060 >> DAVID Malan: Kwa hakika, ushahidi wa msaada muundo kwamba bila shaka ina 672 00:30:11,060 --> 00:30:15,660 kujengwa nje katika kipindi cha miaka mingi, CS50 wafanyakazi mwaka huu idadi karibu 100, 673 00:30:15,660 --> 00:30:17,170 na kwamba hapa katika Cambridge peke yake. 674 00:30:17,170 --> 00:30:21,240 Wakati huo huo, katika New Haven, je, kuna baadhi 40 TFS na CAS na wanachama wa wafanyakazi huko 675 00:30:21,240 --> 00:30:22,800 kuendesha kozi kama vile. 676 00:30:22,800 --> 00:30:26,125 >> Kuruhusu sisi kuanzisha kwanza, Rob Bowden. 677 00:30:26,125 --> 00:30:26,750 Rob BOWDEN: Hi. 678 00:30:26,750 --> 00:30:27,620 Mimi nina Rob. 679 00:30:27,620 --> 00:30:32,750 Huu ni mwaka wangu sita TFing katika mwendo. 680 00:30:32,750 --> 00:30:37,970 Hivyo, njia yote nyuma katika wangu mwaka Freshman, sikuweza kuchukua CS50. 681 00:30:37,970 --> 00:30:40,270 freshman yako fall-- unaweza kuwa na mazoea 682 00:30:40,270 --> 00:30:43,270 kwamba unaweza tu kuchukua kozi nne na kuna wengi kozi leo. 683 00:30:43,270 --> 00:30:44,450 Kwa hiyo mimi nina kama, eh. 684 00:30:44,450 --> 00:30:48,050 Mimi alichukua AP CS mwaka wangu mwandamizi wa shule ya sekondari ilikuwa ni ya kutisha. 685 00:30:48,050 --> 00:30:48,900 Kwa hiyo, mimi nina kama, eh. 686 00:30:48,900 --> 00:30:50,380 Kompyuta sayansi ni si kwa ajili yangu. 687 00:30:50,380 --> 00:30:53,000 >> Hivyo basi ni juu ya mwendo wa freshman yangu 688 00:30:53,000 --> 00:30:58,960 kuanguka, kwamba mimi alikuwa na rafiki katika CS50, na Nadhani walihudhuria hotuba moja na yake. 689 00:30:58,960 --> 00:31:03,760 Ni kama, loo, hii ni aina ya bora kuliko kile alikuwa katika shule ya sekondari. 690 00:31:03,760 --> 00:31:06,990 >> Na juu ya zamu ya mwaka, nilikuwa na yangu mwenyewe seti tatizo 691 00:31:06,990 --> 00:31:08,750 katika kozi Mimi kwa kweli kuchukua. 692 00:31:08,750 --> 00:31:11,870 Lakini mimi sikuona kuwa wakati mimi alitaka akhiri juu ya hizo, 693 00:31:11,870 --> 00:31:15,111 Napenda kurudi nyuma kwa CS50 na kuangalia baadhi ya mambo ambayo. 694 00:31:15,111 --> 00:31:15,610 Hivyo, yeah. 695 00:31:15,610 --> 00:31:16,140 Mimi nina baridi. 696 00:31:16,140 --> 00:31:19,350 Mimi uajizi na coding. 697 00:31:19,350 --> 00:31:22,910 Hivyo basi ni mwishoni mwa kuanguka kwamba mimi kutambua, hey, 698 00:31:22,910 --> 00:31:24,410 sayansi ya kompyuta ni pretty cool. 699 00:31:24,410 --> 00:31:27,730 Mimi kuishia kuchukua CS51. 700 00:31:27,730 --> 00:31:30,430 Katika muhula ujao, Mimi kuishia kuchukua CS61. 701 00:31:30,430 --> 00:31:32,727 Na yote kutoka huko, basi mimi kuishia kutangaza 702 00:31:32,727 --> 00:31:35,310 sayansi ya kompyuta, ambayo nilikuwa kabisa hakuna nia ya kufanya 703 00:31:35,310 --> 00:31:36,740 nilipofika katika chuo. 704 00:31:36,740 --> 00:31:39,330 Na sasa niko hapa. 705 00:31:39,330 --> 00:31:42,230 Hivyo bila shaka ni nini kufanya yake. 706 00:31:42,230 --> 00:31:43,463 Natumaini kufurahia. 707 00:31:43,463 --> 00:31:44,066 >> [Makofi] 708 00:31:44,066 --> 00:31:45,315 DAVID Malan: Asante kwa Rob. 709 00:31:45,315 --> 00:31:49,020 710 00:31:49,020 --> 00:31:52,180 >> Na sasa Maria, yetu kichwa shaka msaidizi. 711 00:31:52,180 --> 00:31:53,140 >> MARIA: Hey guys. 712 00:31:53,140 --> 00:31:53,880 Jina langu ni Maria. 713 00:31:53,880 --> 00:31:56,930 Mimi nina sophomore katika Cabot House, kuja kutoka Bulgaria, 714 00:31:56,930 --> 00:31:59,880 na mimi nina super msisimko kuwa sehemu ya wafanyakazi mwaka huu. 715 00:31:59,880 --> 00:32:03,380 Mimi alichukua CS50 kama freshman mwaka jana, na mimi kamwe hata 716 00:32:03,380 --> 00:32:04,750 mawazo kuhusu CS kabla. 717 00:32:04,750 --> 00:32:08,380 Hivyo mimi upendo kabisa bila shaka, na mimi hope wote kupenda kama vile mimi. 718 00:32:08,380 --> 00:32:09,250 Na, yeah. 719 00:32:09,250 --> 00:32:10,868 Karibu CS50. 720 00:32:10,868 --> 00:32:12,201 DAVID Malan: Asante kwa Maria. 721 00:32:12,201 --> 00:32:13,674 [Makofi] 722 00:32:13,674 --> 00:32:16,129 723 00:32:16,129 --> 00:32:19,580 Sasa Hanna, mafundisho kichwa wenzetu. 724 00:32:19,580 --> 00:32:20,480 HANNA: Hi, mimi nina Hanna. 725 00:32:20,480 --> 00:32:22,990 Mimi nina mwandamizi katika Cabot kusoma sayansi ya kompyuta. 726 00:32:22,990 --> 00:32:28,120 Mimi alichukua CS50 kama freshman na alikuwa imekuwa TFing-- hii utakuwa na mwaka wangu wa tatu. 727 00:32:28,120 --> 00:32:31,000 Hivyo mimi itakuwa furaha kushiriki katika CS50 kwa miaka minne, 728 00:32:31,000 --> 00:32:33,569 na mimi nina kuangalia mbele kufanya kazi na wewe wote. 729 00:32:33,569 --> 00:32:34,902 DAVID Malan: Asante kwa Hanna. 730 00:32:34,902 --> 00:32:36,870 [Makofi] 731 00:32:36,870 --> 00:32:37,854 732 00:32:37,854 --> 00:32:40,274 Na Mwisho, Daven, precepter yetu. 733 00:32:40,274 --> 00:32:40,940 Daven: Hey guys. 734 00:32:40,940 --> 00:32:42,390 Mimi nina amri juu katika sayansi ya kompyuta hapa. 735 00:32:42,390 --> 00:32:44,010 Hii utakuwa na mwaka wa nne mafundisho yangu. 736 00:32:44,010 --> 00:32:45,261 Mimi pia kusaidia kusimamia bila shaka. 737 00:32:45,261 --> 00:32:47,801 Hivyo mimi nina uhakika utaona yangu karibu, hasa katika masaa ya ofisi. 738 00:32:47,801 --> 00:32:48,970 Mimi nina daima katika masaa ya ofisi. 739 00:32:48,970 --> 00:32:51,640 Hivyo kama unaweza kuona mimi kutembea kote, dhahiri kuja kusema hi. 740 00:32:51,640 --> 00:32:52,681 Mimi upendo kukutana kila mtu. 741 00:32:52,681 --> 00:32:55,830 Vinginevyo, kuwa na furaha, na mimi itabidi kuona wewe karibu. 742 00:32:55,830 --> 00:32:58,210 >> DAVID Malan: Asante kwa Daven vilevile. 743 00:32:58,210 --> 00:33:01,290 Hivyo itabidi kukutana yote ya folks hizi kabla ya muda mrefu. 744 00:33:01,290 --> 00:33:03,040 Lakini bila ya zaidi ado, kama wewe guys ingekuwa 745 00:33:03,040 --> 00:33:05,840 kama na kuanza viti yako kutoka mapema. 746 00:33:05,840 --> 00:33:10,940 Naomba kuanzisha kutoka mbali sasa baadhi ya marafiki zetu kutoka New Haven, 747 00:33:10,940 --> 00:33:14,690 katika vichwa hasa kozi ya nani itabidi kuwa kusimamia CS50 there-- Profesa 748 00:33:14,690 --> 00:33:19,550 Brian Scassellati, Yasoni, na Andi, ambao just-- hivyo kwamba hatukuwa kumjaribu hatma 749 00:33:19,550 --> 00:33:22,610 na yoyote FaceTime au like-- tu waliotutuma dakika 750 00:33:22,610 --> 00:33:27,380 iliyopita video zifuatazo ambazo wanasema hodi kutoka ukumbi 751 00:33:27,380 --> 00:33:31,480 katika Yale, ambapo hotuba ni kuwa streamed hivi sasa. 752 00:33:31,480 --> 00:33:34,052 >> Hivyo marafiki zetu kutoka Yale. 753 00:33:34,052 --> 00:33:35,260 BRIAN SCASSELLATI: Hi, David. 754 00:33:35,260 --> 00:33:36,480 Hi, kila mtu katika Harvard. 755 00:33:36,480 --> 00:33:41,400 Sisi ni hivyo msisimko kuwa na kuleta CS50 kwa Yale muhula huu. 756 00:33:41,400 --> 00:33:45,250 Jina langu ni Brian Scassellati, lakini kila mtu tu anataka mimi Scas. 757 00:33:45,250 --> 00:33:50,402 Na mimi niko hapa leo kuanzisha na wewe wafanyakazi CS50. 758 00:33:50,402 --> 00:33:52,346 >> [Wakishangilia] 759 00:33:52,346 --> 00:33:55,760 760 00:33:55,760 --> 00:33:59,780 >> Na muhimu zaidi, mimi nina hapa kwa kuanzisha pamoja 761 00:33:59,780 --> 00:34:03,690 yote ya wanafunzi katika Yale ambao kama ya leo asubuhi 762 00:34:03,690 --> 00:34:09,289 kuwa alifanya hii maarufu Bila shaka katika Yale wanafunzi CS50. 763 00:34:09,289 --> 00:34:12,090 >> [Wakishangilia] 764 00:34:12,090 --> 00:34:25,850 765 00:34:25,850 --> 00:34:28,310 >> Hivyo sisi ni msisimko sana kuwa kuona wewe hapa 766 00:34:28,310 --> 00:34:34,239 siku ya Ijumaa na Jumamosi kwa Puzzle Day na kuwa hotuba kubwa. 767 00:34:34,239 --> 00:34:35,440 Bye. 768 00:34:35,440 --> 00:34:37,360 >> [Makofi] 769 00:34:37,360 --> 00:34:42,170 770 00:34:42,170 --> 00:34:45,497 >> DAVID Malan: Kwenye screen hapa ni majina ya baadhi ya wafanyakazi 140 771 00:34:45,497 --> 00:34:48,330 wanachama ambao wakisubiri wewe juu ya kozi ya semester-- baadhi yao 772 00:34:48,330 --> 00:34:50,540 hapa katika Cambridge, baadhi wao hapa katika New Haven. 773 00:34:50,540 --> 00:34:52,706 Na hakika itabidi fursa hii ya Jumamosi, 774 00:34:52,706 --> 00:34:54,530 kama Scas maelezo, kwa kuhudhuria CS50 Puzzle Siku. 775 00:34:54,530 --> 00:34:57,780 Unaweza kuwa na kuonekana vipande puzzle kidogo slipped chini ya doorways yako hivi karibuni. 776 00:34:57,780 --> 00:35:00,420 Tuna extras chache hapa baadaye wakati wewe kuwepo. 777 00:35:00,420 --> 00:35:04,030 Kama wewe kukusanyika yote puzzle nne vipande na kuunganisha vikosi pamoja na vyumba 778 00:35:04,030 --> 00:35:06,450 lenu jirani katika yako nyumba au Dorm, wao itabidi 779 00:35:06,450 --> 00:35:09,690 kukusanyika katika QR code-- au mbili dimensional bar code, kwamba 780 00:35:09,690 --> 00:35:12,970 mara moja walikutana na scanned na simu yako nitakuongozeni 781 00:35:12,970 --> 00:35:17,060 kwa baadhi ya tuzo fabulous or-- nadhani unaweza tu kupiga picha hii sasa 782 00:35:17,060 --> 00:35:17,560 vilevile. 783 00:35:17,560 --> 00:35:22,560 >> Lakini kupata vipande wale puzzle hata hivyo ili kushinda kwamba tuzo Fabulous. 784 00:35:22,560 --> 00:35:25,900 Na hakika moja ya mila katika SC50-- ah, polepole mno. 785 00:35:25,900 --> 00:35:29,790 Moja ya mila katika CS50 ni kutumikia keki baada ya hotuba ya kwanza. 786 00:35:29,790 --> 00:35:31,620 >> Na hivyo kweli kweli, dakika chache kutoka sasa, 787 00:35:31,620 --> 00:35:36,040 kutakuwa na keki aliwahi nje wote hapa na New Haven vilevile. 788 00:35:36,040 --> 00:35:39,530 >> Lakini first-- sisi decorated yao wenyewe. 789 00:35:39,530 --> 00:35:43,360 Lakini first-- na hopefully kutakuwa na kutosha. 790 00:35:43,360 --> 00:35:44,830 >> Lakini kwanza, haraka kuangalia. 791 00:35:44,830 --> 00:35:47,880 Hivyo mihadhara ni kweli itakuwa zikitengenezwa hapa katika Cambridge. 792 00:35:47,880 --> 00:35:51,580 Lakini kila mwezi, tutaweza hop chini ya Yale na timu ya uzalishaji CS50 na mkondo 793 00:35:51,580 --> 00:35:53,730 Bila shaka katika reverse mwelekeo pamoja ili 794 00:35:53,730 --> 00:35:56,840 kama kuleta vyuo vikuu hizi mbili kweli kwa mara ya kwanza katika historia 795 00:35:56,840 --> 00:36:00,450 kama karibu pamoja iwezekanavyo kama moja katika mwendo huo. 796 00:36:00,450 --> 00:36:04,050 >> Katika suala la muundo msaada kwamba ni wamekuwa alisimama hapa katika Cambridge pamoja 797 00:36:04,050 --> 00:36:05,646 kama katika New Haven, ni sehemu. 798 00:36:05,646 --> 00:36:08,020 Hakika, kama baadhi yenu may kujua, tuna nyimbo tofauti 799 00:36:08,020 --> 00:36:10,850 ndani ya kozi kwa wale chini starehe, vizuri zaidi, 800 00:36:10,850 --> 00:36:14,610 na mahali fulani katika kati ili bila kujali background yako kabla, 801 00:36:14,610 --> 00:36:17,670 unaweza hatimaye kufanikiwa katika darasa. 802 00:36:17,670 --> 00:36:21,320 >> Ofisi ya masaa wakati huo huo, ni nafasi juu ya Jumatatu na Jumanne 803 00:36:21,320 --> 00:36:26,570 na Alhamisi jioni kufanya kazi zote mbili hapa na katika New Haven juu ya kozi yetu ya 804 00:36:26,570 --> 00:36:30,370 tatizo seti na kadhaa wa wafanyakazi kozi ya karibu na wewe. 805 00:36:30,370 --> 00:36:35,380 >> Tatizo seti wakati huo huo, ni mkono na mambo tunaita 806 00:36:35,380 --> 00:36:39,140 walkthroughs, ambayo ni video makao tutorials kwamba kweli kujibu Maswali 807 00:36:39,140 --> 00:36:41,670 ya wapi kuanza changamoto wiki. 808 00:36:41,670 --> 00:36:44,290 Na postmortems kutembea wewe kupitia ufumbuzi iwezekanavyo 809 00:36:44,290 --> 00:36:46,490 ili mwisho wa tatizo kuweka pia, wewe 810 00:36:46,490 --> 00:36:50,820 kujua hasa ni nini wangefanya tofauti au kabisa vinginevyo. 811 00:36:50,820 --> 00:36:53,895 >> tatizo seti wenyewe kuja katika matoleo mawili, toleo la kawaida 812 00:36:53,895 --> 00:36:57,510 kwamba tunatarajia na kukaribisha zaidi ya class-- baadhi 90% plus do-- 813 00:36:57,510 --> 00:37:00,520 na kinachojulikana toleo hacker ambayo kila ukurasa ni emblazoned 814 00:37:00,520 --> 00:37:02,790 toleo hacker, hacker toleo, toleo hacker, 815 00:37:02,790 --> 00:37:07,550 hivyo kwamba una kuwa karma kama wewe, kwa mbizi 816 00:37:07,550 --> 00:37:10,230 katika matoleo ya juu zaidi ya seti tatizo kozi ya 817 00:37:10,230 --> 00:37:14,970 kwamba cover zenye vifaa hivyo lakini pamoja na mbinu za kisasa zaidi 818 00:37:14,970 --> 00:37:19,020 na kutokana na historia ya ziada wakati mwingine vishawishi. 819 00:37:19,020 --> 00:37:22,350 >> Wakati huo huo, kuna siku tisa marehemu kwamba unaweza kuomba kwa tatizo kozi ya 820 00:37:22,350 --> 00:37:26,160 seti kama vile alama ya chini, ambayo sisi kuacha katika suala mwisho. 821 00:37:26,160 --> 00:37:26,900 >> Lakini watapata nini? 822 00:37:26,900 --> 00:37:29,300 Naam, ladha ya tatizo seti katika mkono siku ya Ijumaa 823 00:37:29,300 --> 00:37:31,959 na wiki ijayo ambapo sisi dabble kwa siku chache tu katika kitu 824 00:37:31,959 --> 00:37:35,000 aitwaye Scratch, programu graphical lugha zilizotengenezwa na marafiki zetu 825 00:37:35,000 --> 00:37:39,290 katika MIT Media Lab ya kwamba utapata mpango ama kwa mara ya kwanza 826 00:37:39,290 --> 00:37:43,510 au katika mazingira mapya kabisa kutumia Drag na kuacha aina ya mazingira. 827 00:37:43,510 --> 00:37:45,595 Ambapo vipande puzzle tu interlock pamoja 828 00:37:45,595 --> 00:37:48,080 kama inafanya hisia mantiki ya kufanya hivyo. 829 00:37:48,080 --> 00:37:50,440 >> Wakati huo huo katika tatizo kuweka mbili mwaka jana kwa mfano, 830 00:37:50,440 --> 00:37:53,010 hatukufanya kuanzisha darasa la katika ulimwengu wa cryptography, 831 00:37:53,010 --> 00:37:55,370 sanaa ya encrypting au scrambling habari. 832 00:37:55,370 --> 00:37:58,940 Hakika, huu maandishi hapa ikiwa decrypted, kwa kweli 833 00:37:58,940 --> 00:38:01,277 kusababisha wewe na baadhi ya marudio ya kujifurahisha. 834 00:38:01,277 --> 00:38:03,110 Na katika tatizo kuweka, nini tulikuwa wanafunzi 835 00:38:03,110 --> 00:38:06,280 kufanya ni kutekeleza hasa wale aina ya things-- algorithm, 836 00:38:06,280 --> 00:38:09,530 au seti ya maelekezo kwa ajili ya scrambling na scrambling habari. 837 00:38:09,530 --> 00:38:11,850 >> Na katika toleo hacker ya tatizo kuweka kwamba huo, 838 00:38:11,850 --> 00:38:15,800 hatukufanya changamoto wanafunzi kuchukua encrypted faili kutoka kompyuta ya kawaida 839 00:38:15,800 --> 00:38:18,840 mfumo kwa kura ya majina ya watumiaji na nywila encrypted 840 00:38:18,840 --> 00:38:21,400 na ufa passwords-- wale kweli kufikiri 841 00:38:21,400 --> 00:38:25,870 kile walichokuwa bila kujua chochote priori kuhusu nywila wale halisi. 842 00:38:25,870 --> 00:38:27,620 Wakati huo huo, kufanya sisi mpito katika tatizo 843 00:38:27,620 --> 00:38:29,536 seti ya basi kuangalia ulimwengu wa graphics. 844 00:38:29,536 --> 00:38:32,240 Na kwa kweli, unaweza kufikiria sasa kwamba hii inaweza labda 845 00:38:32,240 --> 00:38:35,200 kuwa njia rahisi ya kuwakilisha nyeusi na nyeupe picha. 846 00:38:35,200 --> 00:38:39,570 >> pixel nyeupe, au mraba, kama utafutaji juu haki pale, 847 00:38:39,570 --> 00:38:41,620 inaweza kuwa kuwakilishwa na 1 na mraba nyeusi 848 00:38:41,620 --> 00:38:43,490 inaweza kuwa kuwakilishwa na 0. 849 00:38:43,490 --> 00:38:47,670 Na tu kwa kutumia bits zaidi kama sisi mapendekezo ya awali na 72 na 73 na 33, 850 00:38:47,670 --> 00:38:49,882 tunaweza kuwakilisha rangi saizi vilevile. 851 00:38:49,882 --> 00:38:51,590 Na nini cha kufanya wakati wa kuweka hii tatizo ni 852 00:38:51,590 --> 00:38:54,660 ujumla kuchukua stroll kuzunguka chuo na kamera digital, 853 00:38:54,660 --> 00:38:56,730 kuchukua picha ya watu, maeneo, na vitu. 854 00:38:56,730 --> 00:38:59,270 Kisha kwa namna fulani kila muhula, tunaonekana ajali 855 00:38:59,270 --> 00:39:02,600 kufutwa au rushwa kadi ya kumbukumbu juu ya ambayo yote ya picha hizo ni, 856 00:39:02,600 --> 00:39:04,610 na hivyo ni changamoto na kisha kuandika programu 857 00:39:04,610 --> 00:39:09,650 na ambayo kupona JPEGs wale kutoka nakala ya kadi ya kamera yetu. 858 00:39:09,650 --> 00:39:13,550 >> Wakati huo huo, je, sisi mkono wewe baadaye katika mrefu kamusi ya maneno ya Kiingereza 859 00:39:13,550 --> 00:39:16,680 ambazo zina maneno 143,000, na wewe haja ya kuja 860 00:39:16,680 --> 00:39:19,240 na njia smart ya upakiaji yao katika kumbukumbu, 861 00:39:19,240 --> 00:39:22,850 au RAM hivyo kusema, kujibu maswali ya aina hii si kauli, 862 00:39:22,850 --> 00:39:25,910 hii si kauli, kutekeleza kasi Spell kusahihisha kwamba unaweza, 863 00:39:25,910 --> 00:39:28,180 hata wanaweka mwenyewe uwezekano dhidi wanafunzi 864 00:39:28,180 --> 00:39:30,460 kuona ambayo ya wewe anatumia kiasi angalau ya muda 865 00:39:30,460 --> 00:39:33,440 wakati wa mbio kanuni yako na hata kiasi mdogo wa kumbukumbu. 866 00:39:33,440 --> 00:39:36,060 >> Baadaye katika muhula kufanya wewe kweli kutekeleza mtandao yako mwenyewe server. 867 00:39:36,060 --> 00:39:39,470 Hivyo si tu tovuti katika lugha inayoitwa HTML na zaidi, 868 00:39:39,470 --> 00:39:43,300 lakini mtandao wa kompyuta ambayo kwa kweli anasikiliza maombi kwenye mtandao 869 00:39:43,300 --> 00:39:44,460 na anaitikia kwao. 870 00:39:44,460 --> 00:39:47,210 Na hakika, hii ni jinsi sisi kuziba dunia yetu ya C na ambayo utasikia 871 00:39:47,210 --> 00:39:50,550 kuwa ukoo wiki ijayo na PHP na HTML na JavaScript 872 00:39:50,550 --> 00:39:51,820 na CSS na kadhalika. 873 00:39:51,820 --> 00:39:54,820 >> Kwa sababu moja ya mtandao wa kwanza msingi mradi sisi kufanya baadaye katika muhula 874 00:39:54,820 --> 00:39:57,516 ni ya kihistoria CS50 Fedha. 875 00:39:57,516 --> 00:40:02,580 Etrade.com style tovuti ambayo inaruhusu wewe kununua na kuuza hisa karibu 876 00:40:02,580 --> 00:40:08,240 wakati pia kuandika kanuni kuzungumza na Yahoo Finance kupata nusu muda halisi ya hisa 877 00:40:08,240 --> 00:40:11,490 ananukuu ili update kwingineko yako mwenyewe. 878 00:40:11,490 --> 00:40:13,370 >> Lakini mwisho bila shaka, ni project-- mwisho 879 00:40:13,370 --> 00:40:16,960 nafasi ya kufanya kitu chochote zaidi ya riba na wewe ili kutatua tatizo hapa 880 00:40:16,960 --> 00:40:20,970 au zaidi ya riba na wewe hiyo ni kwa namna fulani aliongoza 881 00:40:20,970 --> 00:40:22,670 na masomo ya kujifunza darasani. 882 00:40:22,670 --> 00:40:26,140 >> Na darasa, kama unaweza kujua, unafikia upeo katika kile kinachoitwa CS50 Hackathon 883 00:40:26,140 --> 00:40:29,330 na CS50 Fair na idadi yoyote ya matukio mengine ya kiutamaduni 884 00:40:29,330 --> 00:40:31,770 katika muhula kwamba kuruhusu kujihusisha 885 00:40:31,770 --> 00:40:33,460 na kila mmoja na wafanyakazi kozi. 886 00:40:33,460 --> 00:40:37,170 >> Kwa mfano, katika Moto na Ice katika Sitar mwaka huu, vizuri, siku ya Ijumaa mchana, 887 00:40:37,170 --> 00:40:39,220 sisi kuwakaribisha baadhi ya 50 wanafunzi kwa chakula cha mchana, yeyote 888 00:40:39,220 --> 00:40:41,190 wangependa kujiunga na sisi, mwenyewe, na wafanyakazi, 889 00:40:41,190 --> 00:40:44,840 na marafiki wetu kutoka sekta na alums kuzungumza kuhusu maisha katika ulimwengu wa kweli 890 00:40:44,840 --> 00:40:46,670 na zaidi ya wakati kufurahia chakula cha mchana nzuri. 891 00:40:46,670 --> 00:40:49,050 Wakati Hackathon mapenzi unaweza kuona picha kama hizo 892 00:40:49,050 --> 00:40:53,740 kama haya, ikiwa ni pamoja na mengi ya candy-- na kama ya 2014 kwa ajili ya time-- kwanza 893 00:40:53,740 --> 00:40:55,096 mboga. 894 00:40:55,096 --> 00:40:56,960 >> [Makofi] 895 00:40:56,960 --> 00:40:58,358 896 00:40:58,358 --> 00:41:02,710 >> Lakini kwa 05:00, je eneo la tukio kawaida kuangalia kitu kidogo kama hii. 897 00:41:02,710 --> 00:41:05,330 Na kisha tu wiki au hivyo baadaye, ni CS50 Fair 898 00:41:05,330 --> 00:41:08,270 ambayo baadhi ya 2000 wanafunzi na wafanyakazi na kitivo 899 00:41:08,270 --> 00:41:11,910 wanachama kutoka katika chuo na hela ya vyuo vikuu mwaka huu 900 00:41:11,910 --> 00:41:15,620 kuja kuona na furaha katika mafanikio ya CS50 wanafunzi, ambazo 901 00:41:15,620 --> 00:41:16,140 sasa ni wewe. 902 00:41:16,140 --> 00:41:19,000 >> Na hakika, wakati mwaka huu tutaweza kuwa kuwakaribisha na busing mtu yeyote 903 00:41:19,000 --> 00:41:22,460 katika katika Yale ambao wangependa kuja Cambridge Jumamosi hii kwa CS50 Puzzle 904 00:41:22,460 --> 00:41:26,410 Siku, na tutaweza kufanya exact kitu katika Desemba kwa CS50 Hackathon 905 00:41:26,410 --> 00:41:30,080 ili Harvard na Yale wanafunzi sawa twapokea katika wawili wa matukio hayo. 906 00:41:30,080 --> 00:41:33,630 >> Sisi pia itafanya CS50 maonyesho katika Cambridge na katika New Haven mwaka huu 907 00:41:33,630 --> 00:41:36,480 ili wanafunzi juu ya wote vyuo vikuu na wafanyakazi na kitivo 908 00:41:36,480 --> 00:41:39,260 unaweza kuona kila husika chuo ya accomplishment. 909 00:41:39,260 --> 00:41:41,540 Na mafanikio hayo kushawishi kumbukumbu hizo 910 00:41:41,540 --> 00:41:45,440 kama hii na hii na hatimaye huu, ambamo nyote 911 00:41:45,440 --> 00:41:48,460 kujinasua darasa amevaa kidogo kitu katika ambayo walikuwa hopefully 912 00:41:48,460 --> 00:41:52,680 furaha au fahari kusema kwamba mimi alichukua CS50. 913 00:41:52,680 --> 00:41:55,220 >> Lakini kabla ya hapo na kabla ya sisi kutumika keki, 914 00:41:55,220 --> 00:41:58,980 tumekuwa kuweka together-- shukrani kwa CS50 ya timu ya uzalishaji na kujitegemea fulani 915 00:41:58,980 --> 00:42:03,120 fimbo, tukio moja kwamba sisi kutumia mambo kama hayo for-- wakati sisi Wajumbe 916 00:42:03,120 --> 00:42:05,380 si tu hapa Cambridge lakini pia kwa New Haven 917 00:42:05,380 --> 00:42:08,760 kukusanya hellos chache kutoka wafanyakazi kozi na wote wa folks 918 00:42:08,760 --> 00:42:12,640 atakutana na wote hapa na katika New Haven kipindi cha miezi zifuatazo. 919 00:42:12,640 --> 00:42:15,449 >> Naomba kuanzisha chache zaidi ya wafanyakazi CS50. 920 00:42:15,449 --> 00:42:16,990 Mark Zuckerberg: Je kwamba kufanya hivyo ni kwenda? 921 00:42:16,990 --> 00:42:18,266 Oh, ni kwenda. 922 00:42:18,266 --> 00:42:20,910 Ni kwenda. 923 00:42:20,910 --> 00:42:21,570 Ooh. 924 00:42:21,570 --> 00:42:23,170 Yarr! 925 00:42:23,170 --> 00:42:25,350 >> [MUSIC KUCHEZA Andy Grammer, "HONEY, Mimi nina  GOOD "] 926 00:42:25,350 --> 00:42:29,672 927 00:42:29,672 --> 00:42:32,152 >> MARY: Hii ni Caitlin. 928 00:42:32,152 --> 00:42:34,515 Hiyo ni Jay, na mimi nina Mary. 929 00:42:34,515 --> 00:42:35,140 SATO: Hi, guys. 930 00:42:35,140 --> 00:42:35,640 Mimi nina Sato. 931 00:42:35,640 --> 00:42:36,264 MICHAEL G .: Hi. 932 00:42:36,264 --> 00:42:37,181 Jina langu ni Michael, G. 933 00:42:37,181 --> 00:42:38,014 DOUG LLOYD: Sina. 934 00:42:38,014 --> 00:42:38,540 Hakuna 935 00:42:38,540 --> 00:42:39,310 Mimi nina Doug Lloyd. 936 00:42:39,310 --> 00:42:41,757 Siwezi kuamini kwamba mimi nina kufanya selfie fimbo hivi sasa. 937 00:42:41,757 --> 00:42:42,340 SPIKA 4: Hi. 938 00:42:42,340 --> 00:42:42,560 SPIKA 5: Hi. 939 00:42:42,560 --> 00:42:43,307 SPIKA 6: Hello. 940 00:42:43,307 --> 00:42:44,023 SPIKA 7: Hi. 941 00:42:44,023 --> 00:42:44,648 SPIKA 8: Hey. 942 00:42:44,648 --> 00:42:46,436 Sisi ni kunyongwa nje katika Yale. 943 00:42:46,436 --> 00:42:48,910 Sisi ni kweli msisimko kwa muhula huu kwa sababu ni 944 00:42:48,910 --> 00:42:50,840 mara ya kwanza ni kuja Yale. 945 00:42:50,840 --> 00:42:53,012 Ni kwenda kuwa kushangaza! 946 00:42:53,012 --> 00:42:55,928 >> [Music kucheza] 947 00:42:55,928 --> 00:43:02,190 948 00:43:02,190 --> 00:43:04,664 >> JACOB SCHERBA: jina langu ni Jacob Scherba. 949 00:43:04,664 --> 00:43:08,310 Mimi nina msisimko kufundisha CS50 kwa sababu nadhani 950 00:43:08,310 --> 00:43:11,429 ni kuleta sayansi ya kompyuta kwa watu katika na njia ya kumkaribia. 951 00:43:11,429 --> 00:43:13,220 SPIKA 9: Mimi kwa kweli msisimko kufundisha CS50 952 00:43:13,220 --> 00:43:17,717 kwa sababu mimi alichukua darasa mwaka jana, na ni moja ya madarasa bora. 953 00:43:17,717 --> 00:43:18,425 SPIKA 10: Yeah. 954 00:43:18,425 --> 00:43:20,476 Ushauri wangu ni unapaswa kuchukua CS50. 955 00:43:20,476 --> 00:43:23,350 JACOB SCHERBA: Nilichagua CS kwa sababu Nadhani ni furaha na ubunifu njia 956 00:43:23,350 --> 00:43:25,314 kutatua matatizo kwa njia za uchambuzi. 957 00:43:25,314 --> 00:43:28,480 SPIKA 11: Nyuma wakati mimi nilikuwa kidogo freshman na hofu ya sayansi ya kompyuta 958 00:43:28,480 --> 00:43:30,229 na hofu ya kufanya uhandisi na mambo, 959 00:43:30,229 --> 00:43:34,091 ilikuwa ni darasa la kwanza kwa bidii mimi alichukua, na pia ilikuwa darasa langu favorite milele. 960 00:43:34,091 --> 00:43:36,090 DOUG LLOYD: Hii ni yangu mwaka wa tisa mafundisho CS50. 961 00:43:36,090 --> 00:43:37,482 Hiyo inanifanya sauti hivyo zamani! 962 00:43:37,482 --> 00:43:38,690 Daima kuna kitu kipya. 963 00:43:38,690 --> 00:43:39,550 Daima kuna kitu kusisimua. 964 00:43:39,550 --> 00:43:43,077 Kuna daima changamoto mpya zinazowakabili wanafunzi wapya, na ni furaha ili kuwasaidia 965 00:43:43,077 --> 00:43:44,910 na kwa uzoefu wale changamoto pamoja nao 966 00:43:44,910 --> 00:43:45,925 na kuwasaidia kutatua matatizo yao. 967 00:43:45,925 --> 00:43:47,955 >> SPIKA 12: Wakati mimi kwanza kujifunza jinsi ya kufanya CS, 968 00:43:47,955 --> 00:43:49,413 ilikuwa ni kama kujifunza nguvu super. 969 00:43:49,413 --> 00:43:53,749 Na kuona kwamba katika wanafunzi wengine na kuwasaidia kupitia mchakato kwamba 970 00:43:53,749 --> 00:43:55,665 ni moja ya wengi mambo kuridhisha nimekuwa milele. 971 00:43:55,665 --> 00:43:58,706 >> SPIKA 7: Nilichagua CS kwa sababu katika mwanzo, nilikuwa math concentrator 972 00:43:58,706 --> 00:44:00,497 na mimi alichukua CS50 na akaanguka katika upendo na hayo. 973 00:44:00,497 --> 00:44:02,455 Mimi pia waliona kuwa na CS, mimi naweza kujenga mambo. 974 00:44:02,455 --> 00:44:04,410 Na kwamba, mimi mawazo, alikuwa kweli ya baridi kipengele. 975 00:44:04,410 --> 00:44:08,156 >> SPIKA 13: Baadhi ya ushauri kwa mwezi wanafunzi ni kwenda masaa ya ofisi 976 00:44:08,156 --> 00:44:09,573 na hutegemea nje na TFS kutisha. 977 00:44:09,573 --> 00:44:11,906 SPIKA 14: Anza yako P-seti mapema, kwenda masaa ya ofisi, 978 00:44:11,906 --> 00:44:13,457 kuwa frends na TF yako. 979 00:44:13,457 --> 00:44:14,165 SPIKA 15: Yeah. 980 00:44:14,165 --> 00:44:16,164 Kila kitu alisema. 981 00:44:16,164 --> 00:44:17,997 SPIKA 16: Je, si kuwa hofu ya kuomba msaada. 982 00:44:17,997 --> 00:44:18,980 SPIKA 17: Yeah. 983 00:44:18,980 --> 00:44:22,052 SPIKA 18: Anza yako P-seti mapema. 984 00:44:22,052 --> 00:44:23,760 SPIKA 19: Ni big uzoefu kijamii. 985 00:44:23,760 --> 00:44:25,112 Kufanya mengi ya marafiki kwa njia hii. 986 00:44:25,112 --> 00:44:26,570 SPIKA 14: Nenda kwenye sehemu Ni furaha. 987 00:44:26,570 --> 00:44:28,050 SPIKA 11: I mean, kwenda kwa hayo. 988 00:44:28,050 --> 00:44:28,770 Ni kweli ni vigumu. 989 00:44:28,770 --> 00:44:30,581 Itabidi kupata nje yake nini kuweka ndani yake, 990 00:44:30,581 --> 00:44:32,580 lakini ni kweli na furaha darasani hasa kama wewe ni 991 00:44:32,580 --> 00:44:35,496 tayari kuweka muda ndani yake, lakini inasaidia kama wewe kuweka muda ndani yake. 992 00:44:35,496 --> 00:44:38,336 Utasikia kupata mengi zaidi nje ya hiyo baadaye. 993 00:44:38,336 --> 00:44:38,960 MIKE: Mimi nina Mike. 994 00:44:38,960 --> 00:44:39,882 CAMILLE: Mimi nina Camille. 995 00:44:39,882 --> 00:44:40,590 Hanya: Mimi ni Hanya. 996 00:44:40,590 --> 00:44:41,310 MATT: Mimi nina Matt. 997 00:44:41,310 --> 00:44:42,140 PETER: Mimi ni Peter. 998 00:44:42,140 --> 00:44:42,620 PHILLIP: Mimi ni Phillip. 999 00:44:42,620 --> 00:44:43,495 PATRICK: Mimi ni Patrick. 1000 00:44:43,495 --> 00:44:45,234 Rob BOWDEN: Mimi ni Rob Bowden. 1001 00:44:45,234 --> 00:44:47,150 BRIAN SCASSELLATI: My jina ni Scas, na Haya 1002 00:44:47,150 --> 00:44:49,958 ALL: --is CS50. 1003 00:44:49,958 --> 00:44:50,806 SPIKA 20: Wakati Yale. 1004 00:44:50,806 --> 00:44:51,639 SPIKA 21: Wakati Yale. 1005 00:44:51,639 --> 00:44:52,840 [LAUGHING] 1006 00:44:52,840 --> 00:44:54,270 DAVID Malan: Hiyo ni kwa CS50. 1007 00:44:54,270 --> 00:44:59,000 Tutawapitisheni kutoka Yale juu ya Ijumaa, Puzzle Day siku ya Jumamosi. 1008 00:44:59,000 --> 00:45:00,475 Keki ni sasa aliwahi. 1009 00:45:00,475 --> 00:45:01,640 Hii ni CS50. 1010 00:45:01,640 --> 00:45:05,314 1011 00:45:05,314 --> 00:45:10,992 >> [Music kucheza] 1012 00:45:10,992 --> 00:47:00,434