1 00:00:00,000 --> 00:00:11,952 2 00:00:11,952 --> 00:00:13,800 >> DAVID J. Malan: Allura dan huwa CS50. 3 00:00:13,800 --> 00:00:18,970 U dan kien proprju Colton Ogden CS50, l għal aktar ta 'min l-mużika inti tista' 4 00:00:18,970 --> 00:00:22,820 tniżżel fil soundcloud.com/cs50. 5 00:00:22,820 --> 00:00:26,690 >> Allura llum aħna niffukaw l-aktar fuq l-arti ta 'programmazzjoni. 6 00:00:26,690 --> 00:00:28,980 U aħna jieħdu fejn aħna jitħalla ' off aħħar ġimgħa, li jiffoka 7 00:00:28,980 --> 00:00:31,660 fuq Scratch, li kien dan lingwa ta 'programmar grafika. 8 00:00:31,660 --> 00:00:35,490 U jieħdu l-affarijiet isfel għal livell aktar baxx, użu ta 'programmar aktar tradizzjonali 9 00:00:35,490 --> 00:00:38,420 lingwa magħrufa bħala C. Iżda tul it-triq, jirrealizzaw 10 00:00:38,420 --> 00:00:40,730 li l-istess ideat aħna tkellem dwar il-ġimgħa l-aħħar 11 00:00:40,730 --> 00:00:44,390 se jerġa 'jseħħ mhux biss f'dan il- lingwa C, iżda fil-maġġoranza kull oħra 12 00:00:44,390 --> 00:00:46,350 li aħna nħarsu lejn dan is-semestru. 13 00:00:46,350 --> 00:00:50,247 >> Allura aħna sejjaħ dan ħaġa hawn liema aħħar darba? 14 00:00:50,247 --> 00:00:51,830 Dan huwa rappreżentattiv ta 'dikjarazzjoni. 15 00:00:51,830 --> 00:00:53,080 Allura aħna sejjaħ dan stqarrija. 16 00:00:53,080 --> 00:00:54,100 U ma xi ħaġa. 17 00:00:54,100 --> 00:00:56,910 Huwa ta 'istruzzjoni li kompjuter jew Scratch tista tesegwixxi. 18 00:00:56,910 --> 00:00:59,910 U issa, ejja wkoll tibda ssejjaħ xi ħaġa bħal din funzjoni, 19 00:00:59,910 --> 00:01:02,070 għal raġunijiet aħna għandu hekk ara. 20 00:01:02,070 --> 00:01:03,681 >> Sadanittant, rajna affarijiet bħal dan. 21 00:01:03,681 --> 00:01:05,680 U dawn huma ġeneralment magħrufa bħala dak li jinbena? 22 00:01:05,680 --> 00:01:06,240 >> UDJENZA: Loop. 23 00:01:06,240 --> 00:01:06,860 >> DAVID J. Malan: Allura loop. 24 00:01:06,860 --> 00:01:07,943 Allura pjuttost sempliċi. 25 00:01:07,943 --> 00:01:09,470 Hija litteralment ma dak li jgħid. 26 00:01:09,470 --> 00:01:12,210 U fil Scratch, jekk inti tixtieq li CRAM biċċiet puzzle aktar fil hemm, 27 00:01:12,210 --> 00:01:13,950 il-biċċa se jikber biex tajbin. 28 00:01:13,950 --> 00:01:16,790 U aħna ser tara fil C li nistgħu nagħmlu l-istess ħaġa. 29 00:01:16,790 --> 00:01:20,000 >> Tip ieħor ta 'loop, għalkemm, fil Scratch jista 'jkun għal dejjem, 30 00:01:20,000 --> 00:01:21,820 jew hemm xi numru ta 'approċċi oħra. 31 00:01:21,820 --> 00:01:24,150 Imma ejja tagħti aktar ħarsa eneralista, b'wiċċ 32 00:01:24,150 --> 00:01:27,402 li probabbli pjuttost familjari, fil loops aktar ġenerali. 33 00:01:27,402 --> 00:01:29,110 MARKA Zuckerberg: One ħaġa li l-kompjuters 34 00:01:29,110 --> 00:01:31,860 huma verament tajba lejn huwa tirrepeti jikkmanda. 35 00:01:31,860 --> 00:01:33,910 Bħala persuna, youd tikseb verament bored jekk inti 36 00:01:33,910 --> 00:01:36,730 kellha tagħmel l-istess ħaġa lottijiet ta 'drabi fil-filliera. 37 00:01:36,730 --> 00:01:40,530 Iżda kompjuter tista 'tagħmel l-istess ħaġa miljuni jew saħansitra biljuni ta 'drabi, 38 00:01:40,530 --> 00:01:43,290 u mhux niddejjaq, u jkun kapaċi biex iwettqu li minn verament tajjeb. 39 00:01:43,290 --> 00:01:45,650 >> Hekk per eżempju, jekk I riedu jixtiequ kulħadd 40 00:01:45,650 --> 00:01:48,840 fuq Facebook għal għeluq sninha billi jibgħatilhom email, 41 00:01:48,840 --> 00:01:51,550 jista 'jieħu me aktar minn seklu li attwalment jiktbu out 42 00:01:51,550 --> 00:01:53,000 kollha ta 'dawk emails lill kulħadd. 43 00:01:53,000 --> 00:01:57,780 Iżda biss bi ftit linji tal-kodiċi, I tista ' ikollhom sistema ibgħat email lil kulħadd 44 00:01:57,780 --> 00:01:59,930 fuq Facebook li jixtiequ minnhom birthday kuntenti. 45 00:01:59,930 --> 00:02:02,730 Allura dak hu li loops huma u għaliex dawn qed siewja u xi ħaġa 46 00:02:02,730 --> 00:02:04,740 li l-kompjuters tista 'tagħmel tajjeb ħafna. 47 00:02:04,740 --> 00:02:05,630 >> DAVID J. Malan: Mela jekk inti ħadthom kien il-benefiċjarju 48 00:02:05,630 --> 00:02:07,820 ta 'xi wħud tal-CS50 u Ispazju Dropbox ta 'tard, 49 00:02:07,820 --> 00:02:10,590 dan huwa attwalment preċiżament dak li aħna do, bl-użu kodiċi pjuttost bħal dik. 50 00:02:10,590 --> 00:02:12,600 Aħna essenzjalment ikollhom big spreadsheet li fih 51 00:02:12,600 --> 00:02:15,016 folks ġew inputjar tagħhom ismijiet u indirizzi email. 52 00:02:15,016 --> 00:02:18,160 U aħna kiteb ftit żgħira ta 'kodiċi li tista jtenni fuq dawk l-indirizzi 53 00:02:18,160 --> 00:02:21,860 u bżiq out indirizzi uniċi ħadd każ sottomess ħinijiet multipli. 54 00:02:21,860 --> 00:02:25,120 U wara dan, aħna ibgħat email awtomatizzata minn bot CS50, l 55 00:02:25,120 --> 00:02:27,190 inkluż il-kodiċi tal-kupun. 56 00:02:27,190 --> 00:02:29,290 >> Issa aħna wkoll ħares lejn dan jinbena aħħar darba. 57 00:02:29,290 --> 00:02:33,100 U dan huwa partikolari eżempju ta 'dak? 58 00:02:33,100 --> 00:02:35,050 Allura, yeah, espressjoni Boolean. 59 00:02:35,050 --> 00:02:37,050 U l-forma hija maħsuba biex jaqbdu dan ukoll. 60 00:02:37,050 --> 00:02:39,966 Dawn il-kwistjonijiet kollha tal- jiffurmaw vera jew falza fil Scratch 61 00:02:39,966 --> 00:02:41,590 se tfittex ftit xi ħaġa bħal din. 62 00:02:41,590 --> 00:02:43,200 U aħna sejħa dan espressjoni Boolean. 63 00:02:43,200 --> 00:02:46,170 C'est tabilħaqq veru jew falza, iva jew le. 64 00:02:46,170 --> 00:02:49,150 Huwa mod ta jwieġeb mistoqsija. 65 00:02:49,150 --> 00:02:52,420 >> U Sadanittant inti tista 'tuża dawn Boolean espressjonijiet ġewwa tal constructs 66 00:02:52,420 --> 00:02:54,720 bħal dawn, li ta ' kors huma kundizzjonijiet 67 00:02:54,720 --> 00:02:57,259 jew fergħat, proverbial frieket fit-triq. 68 00:02:57,259 --> 00:02:59,550 U jistgħu jfittxu mhux biss bħal dan, iżda jistgħu wkoll 69 00:02:59,550 --> 00:03:02,080 jkunu elses assoċjati magħhom. 70 00:03:02,080 --> 00:03:05,820 U inti tista 'attwalment jkollhom tliet mod furketta fit-triq jew ta 'erba mod furketta 71 00:03:05,820 --> 00:03:08,340 fit-triq, sempliċiment billi nesting dawn l-affarijiet, 72 00:03:08,340 --> 00:03:10,510 kif tkun taf tara fil Scratch jekk inti ma jkunux diġà. 73 00:03:10,510 --> 00:03:13,550 U kif inti tista 'tagħmel fis-C kif ukoll. 74 00:03:13,550 --> 00:03:16,810 >> Ejja tieħu eneralista ieħor tħares lejn alumnist, kif ukoll, li 75 00:03:16,810 --> 00:03:21,490 tista tippreżenta approċċ differenti biex dawn l-affarijiet imsejħa kondizzjonijiet. 76 00:03:21,490 --> 00:03:24,060 >> Bill Gates: Nies jagħmlu deċiżjonijiet kuljum. 77 00:03:24,060 --> 00:03:27,530 Per eżempju, qabel ma tmur barra int tip ta 'jkollhom jekk dikjarazzjoni li tgħid, 78 00:03:27,530 --> 00:03:31,480 jekk huwa ix-xita allura I bżonn li tikseb ġakketta tiegħi. 79 00:03:31,480 --> 00:03:36,820 U kompjuters huma aqwa ladarba inti tiddeċiedi dawk it-tipi ta 'dikjarazzjonijiet, 80 00:03:36,820 --> 00:03:42,280 li jistgħu b'mod affidabbli tesegwixxi dawk l-affarijiet b'veloċità unbelievable. 81 00:03:42,280 --> 00:03:48,240 U hekk programm tal-kompjuter verament huwa xi ftit ta 'matematika u xi 82 00:03:48,240 --> 00:03:53,050 jekk id-dikjarazzjonijiet fejn id-deċiżjoni gets magħmula. 83 00:03:53,050 --> 00:03:55,020 >> DAVID J. Malan: Allura bħala inti tista 'taf, li kien 84 00:03:55,020 --> 00:03:57,880 folks bħal Bill Gates, Paul Allen, u oħrajn 85 00:03:57,880 --> 00:04:00,240 li verament kicked off l- hekk imsejħa kompjuter personali 86 00:04:00,240 --> 00:04:01,990 rivoluzzjoni xi snin ilu. 87 00:04:01,990 --> 00:04:04,140 Ħsibt, qabel we adsa fis xi administrivia, 88 00:04:04,140 --> 00:04:09,920 aħna'd jirrelataw tale mill-Albuquerque, Mużew New Mexico tal-Istorja Naturali 89 00:04:09,920 --> 00:04:13,650 u x-xjenza fejn xi wħud mill Bill Gates " u stejjer kmieni Paul Allen 90 00:04:13,650 --> 00:04:17,470 huma irrakkontati kif għandna issa PCs lum u MACs u aktar. 91 00:04:17,470 --> 00:04:22,390 Għal dan, għalkemm, għandna bżonn żewġ voluntiera li jkollhom vuċijiet rakkont tajbin ħafna 92 00:04:22,390 --> 00:04:23,735 biex jaqra iskrittura b'leħen għoli. 93 00:04:23,735 --> 00:04:25,530 >> Kull dritt, kif madwar fid-dahar hemmhekk. 94 00:04:25,530 --> 00:04:26,120 Come fuq up. 95 00:04:26,120 --> 00:04:27,770 U kif madwar quddiem hawnhekk. 96 00:04:27,770 --> 00:04:28,340 Come fuq l isfel. 97 00:04:28,340 --> 00:04:29,600 Ħu postijiet tiegħek hawn. 98 00:04:29,600 --> 00:04:32,444 Kif inti guys toħroġ, koppja ta 'avviżi amministrattivi. 99 00:04:32,444 --> 00:04:34,360 sezzjonali, il-proċess jagħżlu sezzjoni, 100 00:04:34,360 --> 00:04:36,068 se tibda din L-Erbgħa sal-Ġimgħa. 101 00:04:36,068 --> 00:04:38,400 Aktar dwar li din ġejjin Erbgħa fil lecture. 102 00:04:38,400 --> 00:04:41,770 >> Sezzjonijiet Super, sadanittant, huma xi ħaġa li noffru ġimgħa d-dieħla 103 00:04:41,770 --> 00:04:45,310 li biha l-klassi intiera huwa mistieden biex jipparteċipaw fil skala pjuttost kbir 104 00:04:45,310 --> 00:04:47,690 sezzjonijiet, waħda aktar comfy, waħda inqas komdi. 105 00:04:47,690 --> 00:04:51,340 U aħna se jħabbar id-dettalji ta 'dak, kif ukoll, aktar tard din il-ġimgħa. 106 00:04:51,340 --> 00:04:53,310 >> Sezzjonijiet Sadanittant, infushom, se tibda 107 00:04:53,310 --> 00:04:57,241 fi tlieta mill-kors ġimgħa, indiċi żero, li tfisser dawk huma ftit ġimgħat 108 00:04:57,241 --> 00:04:57,740 out. 109 00:04:57,740 --> 00:04:58,450 Allura biex ma tinkwetax. 110 00:04:58,450 --> 00:05:01,014 Inti għadhom ma qbiżt xejn flimkien dawk il-linji. 111 00:05:01,014 --> 00:05:03,930 Sadanittant fil-frattemp, jekk inti xi mistoqsijiet amministrattivament, 112 00:05:03,930 --> 00:05:08,120 email myself u Devon u Gabe u Rob f'dan l-indirizz hawn. 113 00:05:08,120 --> 00:05:10,320 >> Fl-aħħar nett, il-problema sett 0 huwa, ovvjament, out. 114 00:05:10,320 --> 00:05:12,320 Inti jista 'jkollok ndunat li fuq il-websajt il-kors tal-. 115 00:05:12,320 --> 00:05:14,840 Hija għandha tipprovdi inti ma ' tweġibiet kollha għall-mistoqsijiet 116 00:05:14,840 --> 00:05:18,250 inti jista 'jkollhom tul it-triq għall- ser tibda bil-sett problema. 117 00:05:18,250 --> 00:05:21,430 Imma jekk issib ruħek fil-bżonn ta 'daqqa t'id, 118 00:05:21,430 --> 00:05:25,020 bil-mezzi kollha jattendu ħinijiet tal-uffiċċju, It-Tnejn, it-Tlieta, l-Erbgħa, il-Ħamis 119 00:05:25,020 --> 00:05:27,290 ta 'din il-ġimgħa fil-għaxija f'erba swali dining. 120 00:05:27,290 --> 00:05:31,650 Ara li URL hemmhekk għall-partikolaritajiet ta 'fejn ħinijiet tal-uffiċċju għandu jkun. 121 00:05:31,650 --> 00:05:34,000 >> Issa Ejja jilħqu tagħna żewġ mistednin hawn illum. 122 00:05:34,000 --> 00:05:34,740 X'hemm isem tiegħek? 123 00:05:34,740 --> 00:05:35,290 >> JAY PAUL: Jay Paul. 124 00:05:35,290 --> 00:05:36,880 >> DAVID J. Malan: Jay Paul, sbieħ li jissodisfaw inti. 125 00:05:36,880 --> 00:05:37,330 >> HIKARI: Hikari. 126 00:05:37,330 --> 00:05:37,975 >> DAVID J. Malan: Hikari? 127 00:05:37,975 --> 00:05:38,250 >> HIKARI: Hikari. 128 00:05:38,250 --> 00:05:38,810 >> DAVID J. Malan: Hikari. 129 00:05:38,810 --> 00:05:39,790 Nizza li jissodisfaw inti ukoll. 130 00:05:39,790 --> 00:05:42,123 Jay Paul u Hikari jkollhom fil- quddiem minnhom fuq dawn il-mużika 131 00:05:42,123 --> 00:05:45,100 stands żewġ skripts li I stampati out dalgħodu mill-Messiku New 132 00:05:45,100 --> 00:05:46,692 Mużew tal-Istorja Naturali u x-Xjenza. 133 00:05:46,692 --> 00:05:48,400 U dak li ħsibt I d tagħmel fuq il-overhead 134 00:05:48,400 --> 00:05:52,830 huwa jakkumpanjaw recitation tiegħek tal-iskrittura u din l-istorja 135 00:05:52,830 --> 00:05:54,700 ma 'xi stampi viżwali, l-ebda sorpriżi. 136 00:05:54,700 --> 00:05:57,512 >> U dak I ghamilt bil-quddiem huwa prehighlight fuq iskrittura tiegħek 137 00:05:57,512 --> 00:05:59,470 dak li għandek taqra, u dak li inti għandek taqra. 138 00:05:59,470 --> 00:06:00,920 U aħna ser essenzjalment paragrafi biss supplenti. 139 00:06:00,920 --> 00:06:03,211 Allura huwa ferm simili inti tista għamlu fil-klassi bl-Ingliż. 140 00:06:03,211 --> 00:06:06,875 Li verament jġiegħlu l-udjenza li jemmnu fil tale tiegħek hawn. 141 00:06:06,875 --> 00:06:07,600 Għandhom aħna? 142 00:06:07,600 --> 00:06:13,272 Allura l-istorja hawnhekk hija, għandna BASIC, u li jibda fil-Cambridge. 143 00:06:13,272 --> 00:06:18,750 >> JAY PAUL: Kien xitwa, 1974, fil Cambridge, Massachusetts 144 00:06:18,750 --> 00:06:20,240 fejn xtiewi jistgħu jkunu kesħin. 145 00:06:20,240 --> 00:06:22,800 A bearded, häired twil ossiġinu li jinħarġu barra kulleġġ jismu 146 00:06:22,800 --> 00:06:27,280 Paul Allen kien drudging madwar Harvard Pjazza, assorbit fil-ħsibijiet tiegħu. 147 00:06:27,280 --> 00:06:31,050 Preokkupazzjoni prinċipali tiegħu f'dawk il-jiem kien kif tikseb ħabib tiegħu, Bill Gates, 148 00:06:31,050 --> 00:06:34,974 biex nieqaf-iskola u jmorru fis-negozju miegħu. 149 00:06:34,974 --> 00:06:37,890 HIKARI: It-tnejn kienu diġà marret permezz ta 'numru ta' intrapriżi tan-negozju 150 00:06:37,890 --> 00:06:40,850 flimkien, li jibdew fil Lakeside iskola fil Seattle fejn 151 00:06:40,850 --> 00:06:45,220 dawn kienu mħallsa fil-ħin tal-kompjuter ħielsa li tittestja kompjuter PDP-10 fi żmien lokali 152 00:06:45,220 --> 00:06:46,580 kumpanija qsim. 153 00:06:46,580 --> 00:06:50,930 Il-pjan l-aktar reċenti kien li nieqaf iskola u jiffurmaw kumpanija tas-software. 154 00:06:50,930 --> 00:06:53,440 Allen kienu telqu Washington State University. 155 00:06:53,440 --> 00:06:58,380 Iżda fl-aħħar minuta, Gates iddeċieda li twaħħal mal Harvard. 156 00:06:58,380 --> 00:07:02,080 >> JAY PAUL: Dik il-ġurnata, qsim Harvard Pjazza, Allen spotted il Jannar, 157 00:07:02,080 --> 00:07:07,530 1975 kwistjoni ta 'Popular Electronics mal-ħabel prinċipali waqfien earth, 158 00:07:07,530 --> 00:07:11,900 Kit Dinja Ewwel minikompjuter biex rivali Kummerċjali Mudelli. 159 00:07:11,900 --> 00:07:14,430 Taħt il-ċima kien stampa ta 'kaxxa żgħira 160 00:07:14,430 --> 00:07:16,160 adorned bi dwal u switches. 161 00:07:16,160 --> 00:07:19,770 Hija kienet tissejjaħ l-Altair mits 8800. 162 00:07:19,770 --> 00:07:24,100 U Allen kien jaf dan kien dak li hu kien tfittex. 163 00:07:24,100 --> 00:07:26,350 >> HIKARI: Jiem ta 'diskussjoni segwita. 164 00:07:26,350 --> 00:07:30,170 Allen Gates mifhuma l- sinifikat tal-Altair. 165 00:07:30,170 --> 00:07:32,480 Huma kienu tkellmu spiss dwar mikroproċessuri 166 00:07:32,480 --> 00:07:35,250 u kienu qed jistennew biex tara dak se jsir magħhom. 167 00:07:35,250 --> 00:07:39,770 Issa kien hemm kit minikompjuter fuq il-kopertura ta 'Popular Electronics. 168 00:07:39,770 --> 00:07:42,830 Hija apparentement kellu l-ebda software s'issa. 169 00:07:42,830 --> 00:07:46,830 Huma immaġina nazzjon ta ' programmaturi dixxendenti fuq mits. 170 00:07:46,830 --> 00:07:49,590 U hekk huma msejħa Ed Roberts, il-kap tal-kumpanija, 171 00:07:49,590 --> 00:07:53,330 jallegaw li jkollhom verżjoni tal- Lingwa ta 'programmar BAŻIĊI kważi lesta 172 00:07:53,330 --> 00:07:54,710 għall-Altair. 173 00:07:54,710 --> 00:07:55,570 Huma ma. 174 00:07:55,570 --> 00:07:58,910 U Roberts jridu jkunu magħrufa dawn ma kinux. 175 00:07:58,910 --> 00:08:03,170 Huwa kien jkollna 10 sejħiet kuljum minn nies li kellhom BAŻIĊI kważi lesta. 176 00:08:03,170 --> 00:08:05,570 U r-rispons istokk tiegħu kien, "L-ewwel persuna 177 00:08:05,570 --> 00:08:11,090 li juri bi ħidma BASIC gets-kuntratt. " 178 00:08:11,090 --> 00:08:13,910 >> JAY PAUL: Gates u Allen qatt ma rajt Altair. 179 00:08:13,910 --> 00:08:17,600 Huma qatt ma anki dehru l- Intel 8080 mikroproċessur 180 00:08:17,600 --> 00:08:19,060 fil-qalba tal-Altair. 181 00:08:19,060 --> 00:08:21,470 Iżda ftit ta 'snin qabel Allen kien kiteb programm 182 00:08:21,470 --> 00:08:25,220 fuq kompjuter mainframe li imitat l-operazzjoni ta 'Intel preċedenti 183 00:08:25,220 --> 00:08:26,217 mikroproċessur. 184 00:08:26,217 --> 00:08:28,300 U din id-darba huma se tagħmel l-istess ħaġa. 185 00:08:28,300 --> 00:08:31,530 186 00:08:31,530 --> 00:08:34,380 >> HIKARI: Bil Intel 8080 manwali fil-ġenb tiegħu, 187 00:08:34,380 --> 00:08:37,770 Allen poġġa bilqiegħda fuq Kompjuter Harvard PDP-10 188 00:08:37,770 --> 00:08:42,010 u kiteb l-emulator u software għodod meħtieġa biex jagħmlu l-ipprogrammar. 189 00:08:42,010 --> 00:08:45,820 Sadanittant Gates waqfet għaddejjin għall-klassijiet u ddedikat lilu nnifsu 190 00:08:45,820 --> 00:08:48,120 għall-iddisinjar tal-BASIC, jużaw kull trick 191 00:08:48,120 --> 00:08:53,130 kien jaf li tikseb l-daqs stabbiliti hawn taħt 4 kilobytes. 192 00:08:53,130 --> 00:08:55,870 >> JAY PAUL: Out fil Albuquerque, Ed Roberts ltqajna sejħa minn Gates 193 00:08:55,870 --> 00:08:59,754 tistaqsi għal dettalji dwar kif il- Altair mmaniġġjati rutini speċifiċi. 194 00:08:59,754 --> 00:09:01,170 Ħadd qatt talab li qabel. 195 00:09:01,170 --> 00:09:02,670 U Roberts bdiet tikseb interessat. 196 00:09:02,670 --> 00:09:05,240 197 00:09:05,240 --> 00:09:07,970 >> HIKARI: Bl-iżvilupp għodod u d-disinn lest, 198 00:09:07,970 --> 00:09:10,780 Gates u Allen kiteb il-kodiċi fuq il-PDP-10, 199 00:09:10,780 --> 00:09:16,060 enlisting student ieħor Harvard, Monte Davidoff, li tikteb rutini matematika. 200 00:09:16,060 --> 00:09:19,450 Wara lejl finali ta ' programmazzjoni, Allen ltqajna fuq pjan 201 00:09:19,450 --> 00:09:22,970 biex iwasslu BASIC tagħhom biex mits. 202 00:09:22,970 --> 00:09:25,800 Hu qatta l-pjan ride out inkwetanti. 203 00:09:25,800 --> 00:09:28,490 U lura fil Cambridge Gates kien inkwetanti. 204 00:09:28,490 --> 00:09:32,100 Huma kienu ttestjati bażiċi tagħhom u huwa kien ħadem fuq il-emulator. 205 00:09:32,100 --> 00:09:35,444 Imma x'jiġri jekk il-emulator kienet żbaljata? 206 00:09:35,444 --> 00:09:37,360 JAY PAUL: Peress li l-pjan avviċinat Albuquerque, 207 00:09:37,360 --> 00:09:40,070 Allen induna li tagħhom BASIC, issa pulit jinsabu 208 00:09:40,070 --> 00:09:42,460 fuq roll żgħir ta ' ippanċjati tejp tal-karta, kieku 209 00:09:42,460 --> 00:09:44,970 tkun inutli mingħajr separata programm, imsejħa loader, li 210 00:09:44,970 --> 00:09:47,550 kieku tgħid il-Altair kif biex taqra l-tejp tal-karta benesseri 211 00:09:47,550 --> 00:09:49,620 mitmugħa fil-magna teletype. 212 00:09:49,620 --> 00:09:52,970 Huwa ħa out notebook tiegħu u malajr mħarrbxa isfel programm loader 213 00:09:52,970 --> 00:09:56,819 fil-lingwa Assemblea, imbagħad manwalment tradotti li fil-1s u 0s 214 00:09:56,819 --> 00:09:57,985 l-Altair jifhem. 215 00:09:57,985 --> 00:10:00,530 216 00:10:00,530 --> 00:10:03,830 >> HIKARI: Allen kien jistenna nadif, ftit, il-kumpanija ta 'teknoloġija għolja 217 00:10:03,830 --> 00:10:05,470 mmexxija mill-irġiel fl-ilbiesi tan-negozju. 218 00:10:05,470 --> 00:10:09,210 Hekk hu kien sorpriż meta Roberts sodisfatti lilu fl-ajruport tfittex bħal Ranch 219 00:10:09,210 --> 00:10:10,270 idejn. 220 00:10:10,270 --> 00:10:12,070 Roberts kien ukoll sorpriż. 221 00:10:12,070 --> 00:10:16,340 Meta hu niżel l-Harvard programmer fi lukanda għalja, 222 00:10:16,340 --> 00:10:20,790 Allen kellha nistqarr li hu ma setgħux jagħtu l-kamra. 223 00:10:20,790 --> 00:10:24,510 >> JAY PAUL: mits, fih innifsu, kien jinsabu fil mall strixxa trab. 224 00:10:24,510 --> 00:10:27,040 Ġewwa fuq cluttered Workbench kien Altair 225 00:10:27,040 --> 00:10:30,390 mgħobbija bi 5 kilobytes ta ' memorja u konnessi permezz ta 'kejbil 226 00:10:30,390 --> 00:10:32,030 għal magna teletype. 227 00:10:32,030 --> 00:10:37,200 Roberts u Kap Inġinier, Bill Yates, stenniet expectantly 228 00:10:37,200 --> 00:10:40,660 bħala Allen toggled loader tiegħu programm fil-Altair. 229 00:10:40,660 --> 00:10:44,980 Il teletype beda chugging kif jinġibed l-tejp tal-karta permezz tal-qarrej tejp. 230 00:10:44,980 --> 00:10:47,215 Hija ħadet forsi 15-il minuta tagħbija il-programm. 231 00:10:47,215 --> 00:10:52,110 Imbagħad il-teletype f'daqqa stampat memorja pront, imbagħad fil-pront lest, 232 00:10:52,110 --> 00:10:55,340 u Allen beda tajping test ftit jikkmanda. 233 00:10:55,340 --> 00:10:57,400 Biex amazement kulħadd, l-software maħduma. 234 00:10:57,400 --> 00:10:58,525 Kien hemm bugs, tal-kors. 235 00:10:58,525 --> 00:11:02,070 Imma l-ħaġa prinċipali kienet maħduma. 236 00:11:02,070 --> 00:11:06,570 >> HIKARI: Aktar tard, fit-triq tagħhom lejn 3.00 $ ikla fil ta Pancho, a wasp tellgħu 237 00:11:06,570 --> 00:11:10,470 fit-tieqa tal-Pickup trakk u stung Allen fuq il-fergħa. 238 00:11:10,470 --> 00:11:13,070 Iżda f'dak il-punt xejn jista jħassru l-burdata. 239 00:11:13,070 --> 00:11:17,210 Il Altair issa kellhom BASIC tagħha, il- ewwel softwer kummerċjali għal dar 240 00:11:17,210 --> 00:11:23,260 kompjuter, magħmula minn Paul Allen u Bill Gates, jagħmlu negozju bħala Microsoft. 241 00:11:23,260 --> 00:11:25,336 >> DAVID J. Malan: Ħafna grazzi għal żewġ qarrejja tagħna. 242 00:11:25,336 --> 00:11:30,690 >> [Applause] 243 00:11:30,690 --> 00:11:32,520 >> DAVID J. Malan: Issa għandek l-għażla tiegħek, 244 00:11:32,520 --> 00:11:35,880 qabel ma titlaq, ta 'sparkly jew tiddix fil-dark-- oh, 245 00:11:35,880 --> 00:11:40,810 stenna sec wieħed, wait-- sparkly u tiddix fid-iljunfant dlam 246 00:11:40,810 --> 00:11:42,534 minn stess Cheng Gong CS50 tal. 247 00:11:42,534 --> 00:11:43,450 HIKARI: Aw, nirringrazzjak. 248 00:11:43,450 --> 00:11:45,324 DAVID J. Malan: All dritt, nirringrazzjak tant. 249 00:11:45,324 --> 00:11:49,855 [Applause] 250 00:11:49,855 --> 00:11:51,105 DAVID J. Malan: storja So vera. 251 00:11:51,105 --> 00:11:54,380 Dan huwa li jgħidu li kollha ta 'dawn magni u l-faċilità li biha aħna 252 00:11:54,380 --> 00:11:56,270 jużawhom issa u jieħdu għall mogħtija, tassew 253 00:11:56,270 --> 00:12:00,070 beda hawn, biss paces ftit minn dan it-teatru attwali. 254 00:12:00,070 --> 00:12:03,930 U issa llum, jekk inti ħadthom ma ġewx, dan huwa Maxwell Dworkin, il-kompjuter 255 00:12:03,930 --> 00:12:05,810 xjenzi bini, wkoll l-kantuniera. 256 00:12:05,810 --> 00:12:09,760 U fit-tieni sular ta 'dan bini ma hang tliet paġni 257 00:12:09,760 --> 00:12:12,740 mill-kodiċi sors oriġinali li Bill Gates u Paul Allen kiteb. 258 00:12:12,740 --> 00:12:14,770 Fil-fatt, jekk l-użu inti zoom fil inti tista 'tara mhux biss 259 00:12:14,770 --> 00:12:17,350 ismijiet tagħhom fil- tat-tip oriġinali, iżda wkoll 260 00:12:17,350 --> 00:12:22,100 firem tagħhom li huma adorned a Ftit snin lura meta l-aħħar żar. 261 00:12:22,100 --> 00:12:25,800 >> Imma dak li kien partikolarment konvinċenti dwar dan huwa dak li stabbiliti biex jagħmlu 262 00:12:25,800 --> 00:12:29,760 kien li jikteb programm li kieku jippermettu lin-nies oħra biex jiktbu 263 00:12:29,760 --> 00:12:30,950 programmi tagħhom stess. 264 00:12:30,950 --> 00:12:34,280 Fiż-żmien kollu kien hemm ma ' din il-magna Altair magħmula mill mits. 265 00:12:34,280 --> 00:12:40,020 U kollha huma meħtieġa kienet xi mod ta ' li jagħmilha faċli għall hobbyists u nies 266 00:12:40,020 --> 00:12:45,300 bħalna f'din il-kamra biex effettivament programm li mingħajr neċessarjament fehim 267 00:12:45,300 --> 00:12:49,060 Kodiċi Assemblea, jew magna kodiċi, jew Alla jipprojbixxu, 0s u 1s. 268 00:12:49,060 --> 00:12:51,190 Aħna programmaturi, bħal dawk f'din il-kamra, aħna 269 00:12:51,190 --> 00:12:54,070 tixtieq li tkun tista 'tesprimi lilna nfusna ferm aktar simili kodiċi psewdo 270 00:12:54,070 --> 00:12:57,330 anki jekk huwa nit daqsxejn aktar picky milli tkellimna aħħar ġimgħa. 271 00:12:57,330 --> 00:13:00,970 Aħna ma rridux li jikteb il-kodiċi bħal dan, li Paul Allen u Bill Gates għamlet. 272 00:13:00,970 --> 00:13:04,850 Aħna, minflok, jridu jiktbu kodiċi li jistenna ftit aktar faċli. 273 00:13:04,850 --> 00:13:07,150 >> Issa dan huwa lingwa magħrufa bħala BASIC. 274 00:13:07,150 --> 00:13:11,497 U l-linja numri hemm dak li inti jużaw biex sempliċiment jinnumera l-linji ta 'kodiċi 275 00:13:11,497 --> 00:13:12,330 li int bil-miktub. 276 00:13:12,330 --> 00:13:14,038 Aħna ma jkollhomx biex tagħmel dan dawn il-jiem. 277 00:13:14,038 --> 00:13:16,060 Iżda int tista 'tara hawn kif ISTAMPAR "hello, dinja" 278 00:13:16,060 --> 00:13:18,660 tabilħaqq preżumibbilment jistampaw biss li. 279 00:13:18,660 --> 00:13:22,710 U iva, liema Bill u Paul ma kien jagħtu s-setgħa lin-nies biex jikteb il-kodiċi bħal dan 280 00:13:22,710 --> 00:13:27,240 minflok of-- jekk inti tagħti ħarsa lejn l- xjenza tal-kompjuter wall-- kodiċi bħal dan. 281 00:13:27,240 --> 00:13:29,290 >> Fil-fatt, CS50 reċentement kellha l-opportunità 282 00:13:29,290 --> 00:13:32,540 biex joqogħdu bilqegħda mal-Professur Harry Lewis fil-Computer Science dipartiment, li 283 00:13:32,540 --> 00:13:34,640 attwalment mgħallma Bill Gates xi snin ilu, 284 00:13:34,640 --> 00:13:38,460 u tkun wieqfa hawn qabel dawk it-tliet paġni ta 'siltiet. 285 00:13:38,460 --> 00:13:39,560 Ejja tagħti ħarsa. 286 00:13:39,560 --> 00:13:45,520 >> HARRY LEWIS: Dak li għandek hawnhekk hija elenkar ta 'biċċa bikrija ta' software 287 00:13:45,520 --> 00:13:50,240 miktub minn Bill Gates u Paul Allen, il-fundaturi ta 'Microsoft. 288 00:13:50,240 --> 00:13:52,570 Allura l-kodiċi huwa interessanti għal żewġ raġunijiet. 289 00:13:52,570 --> 00:13:55,480 L-ewwelnett, sar Ewwel prodott Microsoft, 290 00:13:55,480 --> 00:14:01,810 li kienet interpretu għal il-lingwa ta 'programmar BAŻIĊI. 291 00:14:01,810 --> 00:14:04,940 U t-tieni, dan kien wieħed mill-ewwel tentattivi 292 00:14:04,940 --> 00:14:10,580 biex joħolqu interpretu hekk ordinarja nies jistgħu jużaw il-kompjuters personali. 293 00:14:10,580 --> 00:14:12,670 >> Allura Bill Gates kien undergraduate fil-Harvard. 294 00:14:12,670 --> 00:14:14,820 I bdew tagħlim fil-Harvard fl-1974. 295 00:14:14,820 --> 00:14:16,560 Dan sar fl-1975. 296 00:14:16,560 --> 00:14:20,180 Allura kien kmieni fil-karriera tiegħu u kmieni fil-karriera tiegħi. 297 00:14:20,180 --> 00:14:23,790 I attwalment mgħallma Bill fl kors madwar dan iż-żmien. 298 00:14:23,790 --> 00:14:27,130 Paul Allen ma kienx Harvard student, imma hu 299 00:14:27,130 --> 00:14:31,020 kien l-iskola għolja classmate ta Bill Gates. 300 00:14:31,020 --> 00:14:33,740 Jekk inti ġejjin u ħarsa fil-elenkar, inti ser 301 00:14:33,740 --> 00:14:36,230 attwalment issib terz isem, Monte Davidoff, 302 00:14:36,230 --> 00:14:39,260 li kien classmate Gates tal hawn fil-Harvard. 303 00:14:39,260 --> 00:14:41,340 >> OK, hekk hawn xi kumment interessanti up here. 304 00:14:41,340 --> 00:14:47,150 Hija tgħid "Fil 4K tista 'tħassar għerq ikkwadrat iżda għal loops xorta għandhom jaħdmu. " 305 00:14:47,150 --> 00:14:53,080 OK, iva, liema huwa li jfisser li hemm kienu żewġ modi biex jikkompilaw dan il-programm. 306 00:14:53,080 --> 00:14:57,860 Wieħed kien biex imexxu fuq verżjoni ta 'dan il-kompjuter Altair 307 00:14:57,860 --> 00:15:04,310 li huma biss kellhom 4K kliem ta ' memorja, 4096 kliem ta 'memorja. 308 00:15:04,310 --> 00:15:07,050 Iżda l-verżjoni big kellhom 8k. 309 00:15:07,050 --> 00:15:09,770 U hekk dak li dan jgħid hu li fil-verżjoni 4K 310 00:15:09,770 --> 00:15:12,770 inti kellhom iħassru xi kodiċi li jagħmilha tajbin. 311 00:15:12,770 --> 00:15:14,790 U waħda mill-affarijiet li titħassar 312 00:15:14,790 --> 00:15:16,290 tkun l-rutina għerq kwadrat. 313 00:15:16,290 --> 00:15:20,360 Imma apparentement l- għal-linji għandu xorta 314 00:15:20,360 --> 00:15:26,392 jaħdmu anki meta int kompilazzjoni isfel biss għall-verżjoni 4K tal-kompjuter. 315 00:15:26,392 --> 00:15:29,350 DAVID J. Malan: Allura wieħed mit-temi, kif aħna ser tara fil-xjenza tal-kompjuter, 316 00:15:29,350 --> 00:15:31,430 huwa dan il-kunċett ta ' saffi u estrazzjoni, 317 00:15:31,430 --> 00:15:34,670 u verament wieqfa fuq l-ispallejn ta 'folks li jkunu ġejjin quddiemna, mhux 318 00:15:34,670 --> 00:15:37,890 kuntrarjament għal uħud mill-Gates Bill u Paul Allen narrattiva hawn. 319 00:15:37,890 --> 00:15:40,080 U dak li dan ifisser huwa li llum nistgħu nieħdu għall 320 00:15:40,080 --> 00:15:43,490 mogħtija li l-affarijiet huma attwalment faċli għalina li jikteb il-kodiċi. 321 00:15:43,490 --> 00:15:47,170 Tabilħaqq kodiċi, kif għidna nhar il-Ġimgħa, huwa aktar teknikament magħrufa bħala kodiċi sors. 322 00:15:47,170 --> 00:15:52,210 U huwa dan l-Ingliż simili sintassi li l-aktar xierqa u definiti b'mod aktar sew 323 00:15:52,210 --> 00:15:55,480 minn xi ħaġa bħal kodiċi psewdo, għall li m'hemm l-ebda definizzjoni formali. 324 00:15:55,480 --> 00:15:58,320 >> U llum dak li aħna qed tmur li tiffoka fuq hija kodiċi sors 325 00:15:58,320 --> 00:16:01,010 li tidher bħal dan, li Ċertament ewwel daqqa t'għajn 326 00:16:01,010 --> 00:16:02,690 jistenna kompletament cryptic. 327 00:16:02,690 --> 00:16:08,540 U franchement, huwa mod aktar estetikament kumpless milli l-programm sottostanti huwa. 328 00:16:08,540 --> 00:16:13,300 Dan kollu programm ma, recall, huwa dak li ma ngħidu? 329 00:16:13,300 --> 00:16:14,990 Hija biss prints "bonjour dinja." 330 00:16:14,990 --> 00:16:19,600 U għadhom ħarsa fil-livelli kollha ta 'l-għalf għandna bżonn biex nagħlaq madwar dik il-frażi sempliċi ħafna. 331 00:16:19,600 --> 00:16:21,750 Iżda qabel twil kollha ta ' dawn il-linji u aktar 332 00:16:21,750 --> 00:16:24,800 se jagħmel ħafna sens aħjar għalik. 333 00:16:24,800 --> 00:16:26,940 >> U l-fluss hija kif ġej. 334 00:16:26,940 --> 00:16:31,220 Dak li għandna bżonn għad-dispożizzjoni tagħna huwa li jieħdu kodiċi, bħal sors 335 00:16:31,220 --> 00:16:32,340 kodiċi li aħna biss raw. 336 00:16:32,340 --> 00:16:35,060 U għandna bżonn ta 'programm ġdid run permezz. 337 00:16:35,060 --> 00:16:39,130 Għandna bżonn algoritmi li jistgħu jikkonvertu kodiċi sors, bħal dan, 338 00:16:39,130 --> 00:16:41,932 fis object code, 0s u 1s. 339 00:16:41,932 --> 00:16:43,890 Fi kliem ieħor, liema aħna qed tmur biex jitgħallmu llum 340 00:16:43,890 --> 00:16:46,620 hija kif tagħmel dan, jiktbu kodiċi tas-sors top up, 341 00:16:46,620 --> 00:16:49,930 tgħaddih bħala input għal speċjali programm magħruf bħala kompilatur, 342 00:16:49,930 --> 00:16:52,140 u aħna qed tmur biex jipproduċu kodiċi oġġett. 343 00:16:52,140 --> 00:16:54,600 Liema huwa biss mod fancy ta ' qal aħna se tieħu xi ħaġa 344 00:16:54,600 --> 00:16:58,350 li tidher bħal dan, tgħaddiha fi programm imsejjaħ kompilatur, 345 00:16:58,350 --> 00:17:01,210 jipproduċu kodiċi oġġett li tidher bħal dan. 346 00:17:01,210 --> 00:17:04,720 >> Allura dawn huma litteralment l-mudelli ta '0s u 1s 347 00:17:04,720 --> 00:17:08,550 li huma mifhuma minn Intel kompjuter f'dawn il-jiem, 348 00:17:08,550 --> 00:17:12,480 li jekk interpretata mill-CPU, l-imħuħ ġewwa ta 'kompjuter, 349 00:17:12,480 --> 00:17:16,130 litteralment se jistampa, pjuttost sempliċi, "bonjour dinja." 350 00:17:16,130 --> 00:17:19,670 Issa hemm mod aktar 0s u 1s milli suppost jittama jista 'jkun meħtieġ għal dak. 351 00:17:19,670 --> 00:17:22,520 Iżda dan għaliex aħna qed bini fuq ammont tajjeb ta 'kumplessità 352 00:17:22,520 --> 00:17:24,270 li nistgħu issa tieħu għall mogħtija. 353 00:17:24,270 --> 00:17:27,869 Fi kliem ieħor, ħafna nies intelliġenti tawna ħafna ta 'għodod jibred 354 00:17:27,869 --> 00:17:32,480 u software qawwija li aħna issa jistgħu jagħmlu proġetti ta 'tagħna stess. 355 00:17:32,480 --> 00:17:33,400 >> Mela ejja tibda. 356 00:17:33,400 --> 00:17:36,640 Billi Ġimgħa li għadda, u għall Problema Set 0 din il-ġimgħa, 357 00:17:36,640 --> 00:17:39,000 inti ser tkun playing fil- dinja li tidher bħal dan. 358 00:17:39,000 --> 00:17:42,180 Mill-lum u għall-Problema Issettja 1 ġimgħa d-dieħla, il-kodiċi 359 00:17:42,180 --> 00:17:45,410 huwa ser tfittex ftit aktar cryptic, iżda funzjonalment hija 360 00:17:45,410 --> 00:17:46,940 se tkun l-istess. 361 00:17:46,940 --> 00:17:50,770 Allura avviż, top hija Scratch, qiegħ huwa Scratch C. Franchement 362 00:17:50,770 --> 00:17:52,780 huwa ħafna aktar utent faċli u aċċessibbli. 363 00:17:52,780 --> 00:17:56,890 Imma jekk inti issa tqabbel viżwalment fuq għal qiegħ, hemm tip ta '1-1 364 00:17:56,890 --> 00:17:59,690 korrispondenza bejn il- biċċiet puzzle u l-lingwa 365 00:17:59,690 --> 00:18:00,870 aħna qed dwar li jilagħbu bil. 366 00:18:00,870 --> 00:18:04,420 B'mod partikolari, jgħidu, il- puzzle blu biċċa top up, 367 00:18:04,420 --> 00:18:08,370 hija apparentement ekwivalenti għal dak keyword jew frażi speċjali f'dan lingwa 368 00:18:08,370 --> 00:18:09,062 imsejħa C? 369 00:18:09,062 --> 00:18:09,770 UDJENZA: printf. 370 00:18:09,770 --> 00:18:10,728 DAVID J. Malan: printf. 371 00:18:10,728 --> 00:18:12,140 Dan ifisser l-istampar ifformattjat. 372 00:18:12,140 --> 00:18:15,240 U li jinsab biss fancy mod ta 'tgħid printf fl C 373 00:18:15,240 --> 00:18:18,615 se tkun stqarrija jew funzjoni li prints xi ħaġa għall-iskrin. 374 00:18:18,615 --> 00:18:19,990 Dak ma print-iskrin? 375 00:18:19,990 --> 00:18:23,627 Tkun xi tkun inti għid li ġewwa tal-kwotazzjonijiet, ġewwa ta 'parentesi. 376 00:18:23,627 --> 00:18:25,460 Għalhekk għal darb'oħra, ċertament, hemm ħafna ta 'għalf 377 00:18:25,460 --> 00:18:27,990 li inti għandek li wieħed iżomm f'moħħu, parentesi, kwotazzjonijiet, semicolons, 378 00:18:27,990 --> 00:18:28,656 u kollha ta 'dan. 379 00:18:28,656 --> 00:18:30,600 Iżda kollha ta 'dan huwa tip tal ħdejn il-punt. 380 00:18:30,600 --> 00:18:33,660 Il takeaway interessanti għal issa hija li l-blokk vuċi fil Scratch 381 00:18:33,660 --> 00:18:37,520 huwa pretty ħafna ekwivalenti għal l-istqarrija printf fl C. 382 00:18:37,520 --> 00:18:41,390 >> Sadanittant, il-biċċa puzzle isfar top up, meta bandiera aħdar għafast, 383 00:18:41,390 --> 00:18:44,736 huwa probabbilment ekwivalenti għal dak keyword hawnhekk? 384 00:18:44,736 --> 00:18:45,360 UDJENZA: Main. 385 00:18:45,360 --> 00:18:46,359 DAVID J. Malan: Allura prinċipali. 386 00:18:46,359 --> 00:18:47,410 Forsi int, forsi bla effett. 387 00:18:47,410 --> 00:18:51,280 Iżda tip ewlieni ta 'ħsejjes simili huwa importanti, u tabilħaqq huwa. 388 00:18:51,280 --> 00:18:54,080 Allura meta bandiera aħdar għafast hija, għal darb'oħra, il-biċċa puzzle 389 00:18:54,080 --> 00:18:56,390 li kicks off programm Scratch kollu. 390 00:18:56,390 --> 00:19:02,140 Iżda aħna qed tmur biex issa tibda sejħa li prinċipali, din il-funzjoni magħrufa bħala prinċipali. 391 00:19:02,140 --> 00:19:06,410 >> Issa sadanittant aħna ser tiġġeneralizza dan kif ġej. 392 00:19:06,410 --> 00:19:08,780 Aħna tista 'sejħa ngħidu funzjoni. 393 00:19:08,780 --> 00:19:10,580 U tista 'tidher speċifikament bħal dan. 394 00:19:10,580 --> 00:19:11,770 Ukoll, dak dwar loops? 395 00:19:11,770 --> 00:19:16,540 Jekk irridu li tibda tikkonverti jew traduzzjoni aktar fil Scratch sa C, 396 00:19:16,540 --> 00:19:19,400 dan il-ħaġa hawn apparentement biss jgħid "bonjour dinja" għal dejjem. 397 00:19:19,400 --> 00:19:23,060 Mela jekk inti tassoċja dawn skripts bl qattus fil Scratch, 398 00:19:23,060 --> 00:19:26,560 huwa biss se żżomm qal f'xi tip ta 'cartoons bużżieqa, 399 00:19:26,560 --> 00:19:29,922 "Bonjour dinja, bonjour dinja, bonjour dinja, "ad nauseum, dejjem. 400 00:19:29,922 --> 00:19:33,130 Jekk irridu nagħmlu xi ħaġa simili fil- C, li għaddej biex tfittex ftit cryptic. 401 00:19:33,130 --> 00:19:35,463 Iżda nistgħu niksbu l-istess riżultati, kif aħna ser eventwalment 402 00:19:35,463 --> 00:19:36,861 nsib, ma sintassi bħal dan. 403 00:19:36,861 --> 00:19:39,360 Jien ser tuża printf darb'oħra, għaliex fl-aħħar tal-ġurnata 404 00:19:39,360 --> 00:19:42,040 I tixtieq li jistampaw "bonjour dinja." 405 00:19:42,040 --> 00:19:45,610 U jien apparentement jużaw keyword li mhix dejjem. 406 00:19:45,610 --> 00:19:47,320 Minflok Hu l-kelma waqt. 407 00:19:47,320 --> 00:19:49,650 Iżda biss semantikament fl Ingliż, filwaqt li tip ta ' 408 00:19:49,650 --> 00:19:52,120 jissuġġerixxi xi tip ta 'loop jew ċiklu. 409 00:19:52,120 --> 00:19:55,070 >> Allura li jiġri li jkun l-keyword li C użi. 410 00:19:55,070 --> 00:20:00,700 U filwaqt li veru, għaliex ma filwaqt li veru jfisser effettiv għal dejjem? 411 00:20:00,700 --> 00:20:04,240 Ukoll, filwaqt li, kif aħna ser dalwaqt japprezzaw l-aktar, 412 00:20:04,240 --> 00:20:08,140 għandha dan parenthetical jmiss lilu fejn inti tista 'tpoġġi l-espressjoni Boolean. 413 00:20:08,140 --> 00:20:11,360 U hekk sakemm dik espressjoni huwa veru, dan il-kodiċi, 414 00:20:11,360 --> 00:20:14,750 kif denotat bejn dawn iż-żewġ braces kaboċċi kif aħna ser jsejħulhom, 415 00:20:14,750 --> 00:20:16,880 se biss iżommu running darb'oħra u għal darb'oħra. 416 00:20:16,880 --> 00:20:18,410 >> Allura veru huwa veru. 417 00:20:18,410 --> 00:20:20,900 Għalhekk, filwaqt li mezzi vera biss tagħmel dan għal dejjem. 418 00:20:20,900 --> 00:20:23,480 Huwa kważi stupid jinbena biex tesprimi ruħek. 419 00:20:23,480 --> 00:20:26,590 Imma ma kien hemm ebda dejjem keyword fil C. Ma kien hemm waqt. 420 00:20:26,590 --> 00:20:29,390 U kien hemm sempliċi ħafna Espressjoni Boolean simili veru. 421 00:20:29,390 --> 00:20:32,210 U hekk dan, aħna ser tara, tikseb l-istess riżultat. 422 00:20:32,210 --> 00:20:33,890 >> Kif inkella tista inti jimplimentaw loop? 423 00:20:33,890 --> 00:20:36,980 Ukoll, fil Scratch inti tista kodiċi hard numru speċifiku 424 00:20:36,980 --> 00:20:39,430 tal iterazzjonijiet fil-linja hawnhekk. 425 00:20:39,430 --> 00:20:43,210 U hekk dan huwa eżattament dak li aħna tista 'tagħmel f'dan il-verżjoni ta' C, 426 00:20:43,210 --> 00:20:46,140 li biha għandna hekk imsejħa għall loop. 427 00:20:46,140 --> 00:20:49,850 U l-għar loop hawn se li jtenni, kemmxejn cryptically, 428 00:20:49,850 --> 00:20:54,100 mill-valur 0 fuq up li iżda inqas minn 10. 429 00:20:54,100 --> 00:20:55,955 >> Issa varjabbli fil Scratch. 430 00:20:55,955 --> 00:20:57,830 Inti ma setgħu kellhom okkażjoni biex jużaw dawn. 431 00:20:57,830 --> 00:21:02,516 Imma x'inhu l-punt, b'mod ġenerali, ta 'varjabbli ma ngħidu ġimgħa li għaddiet? 432 00:21:02,516 --> 00:21:03,015 X'hemm li? 433 00:21:03,015 --> 00:21:03,780 >> Udjenza: punti. 434 00:21:03,780 --> 00:21:05,200 >> DAVID J. Malan: Mal-punt? 435 00:21:05,200 --> 00:21:05,700 Oh, il-punti. 436 00:21:05,700 --> 00:21:07,620 OK, iżżomm rekord ta 'punti, per eżempju, fil-logħba. 437 00:21:07,620 --> 00:21:09,510 Jew aktar tagħmel ġeneralment dak mal-varjabbli? 438 00:21:09,510 --> 00:21:10,450 X'hemm l-utilità minnhom? 439 00:21:10,450 --> 00:21:10,825 >> UDJENZA: Memorja. 440 00:21:10,825 --> 00:21:11,750 >> DAVID J. Malan: Yeah, hekk memorja. 441 00:21:11,750 --> 00:21:13,000 Huwa għall-ħażna xi ħaġa. 442 00:21:13,000 --> 00:21:17,336 U l-tip ta 'I viżwali iblah użati aħħar darba kien bħal dan bowl tal-ħġieġ. 443 00:21:17,336 --> 00:21:19,710 U jekk ridna li jaħżnu xi ħaġa ġewwa ta 'varjabbli, 444 00:21:19,710 --> 00:21:21,918 per eżempju id-dritt issa l- valur huwa sitta għaliex hemm 445 00:21:21,918 --> 00:21:23,450 huma sitt blalen ping pong fil hawn. 446 00:21:23,450 --> 00:21:26,158 Huwa biss xi tip ta 'ħażna kontenitur li taħtha il-barnuża 447 00:21:26,158 --> 00:21:30,030 hija implimentata bl bits, 0s u 1s, madankollu kompjuter jiġri li tagħmel dan. 448 00:21:30,030 --> 00:21:32,900 >> Għalhekk fl Scratch, jekk aħna tixtieq li jkollok varjabbli, 449 00:21:32,900 --> 00:21:34,840 nistgħu nużaw blokk oranġjo bħal dan. 450 00:21:34,840 --> 00:21:37,050 Aħna ser sejħa dan counter f'dan il-każ partikolari. 451 00:21:37,050 --> 00:21:38,890 I initialized dan għal 0. 452 00:21:38,890 --> 00:21:41,080 U dak li jien imbagħad do? 453 00:21:41,080 --> 00:21:44,780 Forever, jgħidu counter, li jekk inti play ma 'dik fl Scratch, 454 00:21:44,780 --> 00:21:45,780 tkun taf biss tara Scratch. 455 00:21:45,780 --> 00:21:49,920 Il-qattus jew kwalunkwe kostum inti tpoġġi fuq lilu se jitkellem l-numru in kwistjoni. 456 00:21:49,920 --> 00:21:52,840 >> Bidla counter minn 1 huwa bħal inkrementazzjoni minn 1. 457 00:21:52,840 --> 00:21:56,580 U hekk dan se għadd minn dak iva, liema? 458 00:21:56,580 --> 00:21:59,114 Minn 0 til infinity, jew sakemm pawżi Scratch, 459 00:21:59,114 --> 00:22:01,030 jew sakemm inti tip ta ' jitilfu l-interess fil jaraw 460 00:22:01,030 --> 00:22:02,650 kif għolja jista 'attwalment joqgħod. 461 00:22:02,650 --> 00:22:04,800 >> Allura kif jista aħna jikkonvertu dan C? 462 00:22:04,800 --> 00:22:06,480 Huwa ser tfittex ftit cryptic. 463 00:22:06,480 --> 00:22:08,896 Iżda għal darb'oħra, jekk inti tħares lejn kull ta 'dawn il-linji individwalment 464 00:22:08,896 --> 00:22:10,410 dawn it-tip ta 'lineup ġeneralment. 465 00:22:10,410 --> 00:22:13,526 Allura apparentement Int se għandhom xi tifsira speċjali fil C. 466 00:22:13,526 --> 00:22:14,400 Aħna ser tara li għal darb'oħra. 467 00:22:14,400 --> 00:22:15,810 Bħala twarrib dan ifisser integer. 468 00:22:15,810 --> 00:22:16,990 Allura dan ifisser biss numru. 469 00:22:16,990 --> 00:22:18,920 Allura dak it-tip ta ' ħġieġ skutella Irrid, waħda 470 00:22:18,920 --> 00:22:21,120 li jista 'jaħżen numri, mhux ping pong blalen. 471 00:22:21,120 --> 00:22:25,520 U jien ser tuża s-sinjal ugwali hemm biex tassenja din valur ta '0. 472 00:22:25,520 --> 00:22:29,440 Allura dak pjuttost simili sett counter għal 0, iżda fil C. 473 00:22:29,440 --> 00:22:32,840 >> Sadanittant, filwaqt veru, li kien ekwivalenti, naturalment, biex dejjem, 474 00:22:32,840 --> 00:22:35,980 anki jekk huwa ftit cryptic, u mbagħad ġewwa taċ-ċingi kaboċċi. 475 00:22:35,980 --> 00:22:39,188 U inti tista 'taħseb ta' dawn ċingi kaboċċi, li inti tista tip fuq it-tastiera tiegħek, 476 00:22:39,188 --> 00:22:43,110 bħala verament tkun bħall-kurvatura fl dawn il-blokok loop isfar fil Scratch. 477 00:22:43,110 --> 00:22:45,700 Hi tħaddan diversi linji ta 'kodiċi. 478 00:22:45,700 --> 00:22:48,120 >> Printf huwa jkollna ftit scary issa minħabba I 479 00:22:48,120 --> 00:22:51,120 tara kwotazzjonijiet mhux biss fil-parentesi. 480 00:22:51,120 --> 00:22:55,160 Imma dak li inkella huwa ġdid sintattikament f'dan l-eżempju? 481 00:22:55,160 --> 00:22:57,300 Hemm mija d. 482 00:22:57,300 --> 00:22:58,551 U allura backslash n hemm. 483 00:22:58,551 --> 00:23:00,883 Aħna ma tara li qabel, anki għalkemm I ma jsemmuha. 484 00:23:00,883 --> 00:23:01,886 Imbagħad hemm virgola. 485 00:23:01,886 --> 00:23:03,010 U allura hemm kontro. 486 00:23:03,010 --> 00:23:05,010 >> Iżda aħna ser tara fi ftit mument li dan huwa biss 487 00:23:05,010 --> 00:23:09,080 mod standard ta 'tgħid print a "Numru deċimali," kwotazzjoni, unquote, 488 00:23:09,080 --> 00:23:10,500 xi numru deċimali. 489 00:23:10,500 --> 00:23:13,370 Imma jien ser jgħidlek aktar tard dak li numru deċimali hu. 490 00:23:13,370 --> 00:23:16,835 Allura l-fatt li hemm virgola f'dan il-linja printf qal, 491 00:23:16,835 --> 00:23:18,710 ifisser imorru quddiem u print xi numru deċimali. 492 00:23:18,710 --> 00:23:23,110 Oh, u mill-mod, in-numru huwa ikun x'ikun il-valur ta 'din il-varjabbli. 493 00:23:23,110 --> 00:23:25,880 U hekk biex jagħmlu dan aktar ċara, aħna ser tara eżempju 494 00:23:25,880 --> 00:23:30,930 qabel twil li jinvolvi eżattament printf fil-kuntest ta 'programmi Ċ reali. 495 00:23:30,930 --> 00:23:33,472 >> Issa biss biex nagħlaq xi ta 'dawn constructs. 496 00:23:33,472 --> 00:23:36,680 Espressjonijiet Boolean, inti jista 'ma jkollhomx okkażjoni biex jużaw dawn fil-programm tiegħek 497 00:23:36,680 --> 00:23:39,450 imma inti tista 'tajjeb ħafna, speċjalment jekk jużaw kundizzjonijiet. 498 00:23:39,450 --> 00:23:43,460 U hekk dawn iż-żewġ eżempji mill Scratch jfissirx jekk x huwa inqas minn y, 499 00:23:43,460 --> 00:23:48,770 jew jekk x huwa inqas minn y uy huwa inqas minn z, kif jista aħna tittraduċi li? 500 00:23:48,770 --> 00:23:50,810 >> Ukoll, fil-C huwa biss ser teżamina bħal dan. 501 00:23:50,810 --> 00:23:55,300 A ftit cryptic, aktar parentesi, xi ampersands stramb, iżda fundamentalment 502 00:23:55,300 --> 00:23:59,160 l-ideat huma sempliċi kemm dawn huma fid-dinja biċċa puzzle. 503 00:23:59,160 --> 00:24:02,690 Aħna qed sempliċiment iċċekkjar jekk xi ħaġa huwa inqas minn xi ħaġa oħra. 504 00:24:02,690 --> 00:24:03,910 >> Kif dwar kondizzjonijiet? 505 00:24:03,910 --> 00:24:09,710 Fil-qosor bl-Ingliż, dan xi blokki ta 'kodiċi Scratch do would you say? 506 00:24:09,710 --> 00:24:11,050 >> UDJENZA: Tqabbel żewġ numri. 507 00:24:11,050 --> 00:24:13,760 >> DAVID J. Malan: Tqabbel żewġ numri, u jekk x huwa inqas minn y 508 00:24:13,760 --> 00:24:14,860 jgħid kemm. 509 00:24:14,860 --> 00:24:18,080 Jekk x hija akbar minn y jgħid kemm, inkella 510 00:24:18,080 --> 00:24:20,740 jekk x huwa ugwali għal y jgħid kemm. 511 00:24:20,740 --> 00:24:22,180 Issa fejn ma xuy jiġu minn? 512 00:24:22,180 --> 00:24:22,680 Min jaf. 513 00:24:22,680 --> 00:24:25,380 Dan blokki ta 'Scratch kodiċi huwa barra mill-kuntest. 514 00:24:25,380 --> 00:24:29,050 Imma dak li rridu nagħmlu issa hu tittraduċi dan għal ftit mument biex tara. 515 00:24:29,050 --> 00:24:31,660 >> Allura kif inti tikseb komda din il-ġimgħa fil-Problema Set 516 00:24:31,660 --> 00:24:34,190 0 playing f'din id-dinja fuq ix-xellug, tirrealizza 517 00:24:34,190 --> 00:24:36,940 li l-ideat tagħhom ma jinbidlu din il-ġimgħa jew li jmiss jew lil hinn. 518 00:24:36,940 --> 00:24:38,690 Aħna qed sempliċiment tmur biex tibda bil-miktub affarijiet 519 00:24:38,690 --> 00:24:41,240 b'mod differenti ma 'tagħna tastiera minflok mouse tagħna. 520 00:24:41,240 --> 00:24:44,577 >> Mela jekk x huwa inqas minn y, u hemm xi parentesi hemmhekk, 521 00:24:44,577 --> 00:24:47,160 allura hemm xi braces kaboċċi darb'oħra biex tip ta 'jirrappreżentaw dan 522 00:24:47,160 --> 00:24:48,970 bħad-biċċiet puzzle isfar do. 523 00:24:48,970 --> 00:24:53,000 U jien ser printf x huwa inqas minn y u ibqa 'sejjer hekk. 524 00:24:53,000 --> 00:24:56,540 >> X'inhu sbieħ dwar C, kif tistgħu taraw hawn, 525 00:24:56,540 --> 00:25:00,480 hija li inti ma tieħux dan ibejtu, ibejtu, nesting thats neċessarjament 526 00:25:00,480 --> 00:25:02,220 ser timbotta kodiċi tiegħek lejn il-lemin. 527 00:25:02,220 --> 00:25:04,990 Tista minflok jkollhom kollox lineup pulit bħal dan. 528 00:25:04,990 --> 00:25:08,960 Imma dak li biss estetika dettall aħna ser tara darb'oħra qabel twil. 529 00:25:08,960 --> 00:25:09,660 >> Kull dritt. 530 00:25:09,660 --> 00:25:13,290 Allura li twassalna lura għall dan il-programm cryptic tfittex. 531 00:25:13,290 --> 00:25:15,180 Ejja attwalment jikteb xi kodiċi. 532 00:25:15,180 --> 00:25:16,830 Issa kif taħseb li tmur dwar kitba kodiċi? 533 00:25:16,830 --> 00:25:21,310 Kollha dawn is-snin li inti stajt proprjetà Mac jew PC, desktop jew laptop, 534 00:25:21,310 --> 00:25:24,520 inti stajt attwalment kellu l-kapaċità biex tibda tikteb kodiċi ta 'programmazzjoni. 535 00:25:24,520 --> 00:25:27,050 Imma int probabilment nieqsa tip speċjali ta 'programm. 536 00:25:27,050 --> 00:25:28,470 Inti tista 'ċertament jikteb il-kodiċi. 537 00:25:28,470 --> 00:25:30,740 Imma inti ma tistax neċessarjament, barra mill-kaxxa, 538 00:25:30,740 --> 00:25:34,210 jikkonvertu dan il-kodiċi sors f'Kodiċi oġġett, 0s u 1s 539 00:25:34,210 --> 00:25:35,619 mingħajr dak fuq il-kompjuter tiegħek? 540 00:25:35,619 --> 00:25:36,410 UDJENZA: kompilatur. 541 00:25:36,410 --> 00:25:37,630 DAVID J. Malan: Allura kompilatur, id-dritt. 542 00:25:37,630 --> 00:25:39,730 Issa ħafna minnkom probabbilment ma proprji kompilatur, 543 00:25:39,730 --> 00:25:41,259 qatt ma jitniżżel kompilatur. 544 00:25:41,259 --> 00:25:44,300 Imma inti taf tara tista 'tniżżel bħal ħafna xi biċċa oħra ta 'software. 545 00:25:44,300 --> 00:25:47,470 Fid-dinja ta 'Mac OS, inti tista tniżżel jew niżżilt diġà 546 00:25:47,470 --> 00:25:50,437 xi ħaġa imsejħa Xcode jew GCC jew Clang. 547 00:25:50,437 --> 00:25:52,270 Jekk inti ġejjin mill- Windows dinja inti tista 548 00:25:52,270 --> 00:25:56,190 niżżilt Visual Studio, Visual Basic, ambjenti bħal dik. 549 00:25:56,190 --> 00:25:59,200 Hemm għexieren ta 'kompilaturi dawn il-jiem li inti tista 'tuża. 550 00:25:59,200 --> 00:26:01,940 Iżda l-qasir ta 'dan hawn huwa li jkun uġigħ 551 00:26:01,940 --> 00:26:04,480 u, franchement, a teknoloġiku ħmar il-lejl għal mijiet 552 00:26:04,480 --> 00:26:07,680 ta 'nies ma differenti Konfigurazzjonijiet kompjuter għal kulħadd 553 00:26:07,680 --> 00:26:09,800 kkonfigurat magni tagħhom eżattament fl-istess mod 554 00:26:09,800 --> 00:26:11,700 hekk li aħna kollha jistgħu jkunu fuq l-istess paġna. 555 00:26:11,700 --> 00:26:15,240 >> Allura dak li aħna, minflok, do fil CS50 huwa aħna nagħtuk 556 00:26:15,240 --> 00:26:18,349 ambjent standard, a Linux ambjent li l- 557 00:26:18,349 --> 00:26:20,140 ser tfittex ftit xi ħaġa bħal din. 558 00:26:20,140 --> 00:26:22,980 Int ser ikollok tara aktar ta 'dan fil- Problema Set 1 speċifikazzjoni li 559 00:26:22,980 --> 00:26:25,330 se jmorru online dan Ġimgħa bil-lejl. 560 00:26:25,330 --> 00:26:28,360 >> U dak li dan ifisser hija li inti issa 561 00:26:28,360 --> 00:26:32,060 ser ikunu kapaċi tniżżel u tinstalla programm 562 00:26:32,060 --> 00:26:33,650 imsejjaħ il-Appliance CS50. 563 00:26:33,650 --> 00:26:36,275 U int ser tniżżel u jinstallaw program oħra msejħa 564 00:26:36,275 --> 00:26:40,300 hypervisor, li huwa biss mod fancy ta 'kisba ta' dan. 565 00:26:40,300 --> 00:26:44,600 Jekk inti stess Mac jew PC jew Linux kompjuter jew kompjuter Solaris, 566 00:26:44,600 --> 00:26:46,830 jew kwalunkwe operattiva crazy sistema int taħdem, 567 00:26:46,830 --> 00:26:49,820 int ser tniżżel programm imsejjaħ il-hypervisor li l- 568 00:26:49,820 --> 00:26:53,350 ser imexxu l-CS50 Appliance fuq il-kompjuter tiegħek 569 00:26:53,350 --> 00:26:55,430 x'ikun sistema operattiva tiegħek hija. 570 00:26:55,430 --> 00:27:00,640 A hypervisor fi kliem ieħor tikkonverti Jittieħed tagħna għal dak kollu lingwa, 571 00:27:00,640 --> 00:27:03,850 x'ikun istruzzjonijiet tiegħek kompjuter stess jifhem. 572 00:27:03,850 --> 00:27:04,962 >> Allura dan huwa saffi. 573 00:27:04,962 --> 00:27:06,920 U għal darb'oħra, dan huwa tip ta tematika fil-kompjuter 574 00:27:06,920 --> 00:27:08,722 xjenza, il-bini fuq quċċata ta 'affarijiet. 575 00:27:08,722 --> 00:27:09,680 Inti jista 'jkollok Windows. 576 00:27:09,680 --> 00:27:10,710 Inti jista 'jkollok Mac OS. 577 00:27:10,710 --> 00:27:12,960 Iżda jibdew il-ġimgħa d-dieħla int ser niżżilt 578 00:27:12,960 --> 00:27:14,980 biċċa ħieles ta 'softwer imsejjaħ il-hypervisor. 579 00:27:14,980 --> 00:27:17,800 Inti qed tmur biex niżżilt biċċa ta 'softwer imsejjaħ il-Appliance CS50. 580 00:27:17,800 --> 00:27:21,050 >> Li għaddej biex imexxu fil-hypervisor, li se jimxu fuq il-kompjuter tiegħek. 581 00:27:21,050 --> 00:27:23,030 U r-riżultat aħħari huwa li lkoll se 582 00:27:23,030 --> 00:27:26,220 jkollhom tieqa sempliċi bħal dan fuq Mac tiegħek jew PC 583 00:27:26,220 --> 00:27:30,160 li jagħtina l-illużjoni ta 'kulħadd jmexxu l-istess sistema operattiva, 584 00:27:30,160 --> 00:27:32,800 mingħajr ebda oħra impatt fuq il-kompjuter tiegħek. 585 00:27:32,800 --> 00:27:34,870 U inti tista full screen dan u essenzjalment jġib ruħu 586 00:27:34,870 --> 00:27:37,550 daqslikieku inti taħdem sistema operattiva imsejħa Linux, 587 00:27:37,550 --> 00:27:40,270 li huwa dak li l-CS50 Appliance hija bbażata fuq. 588 00:27:40,270 --> 00:27:42,930 >> Mela ejja attwalment jużaw dan issa biex jikteb programm. 589 00:27:42,930 --> 00:27:45,450 Tista 'tikteb programm jużaw Microsoft Word. 590 00:27:45,450 --> 00:27:48,160 Tista 'tikteb programm użu TextEdit, jew notepad, 591 00:27:48,160 --> 00:27:51,880 jew WordPad, jew pretty ħafna xi kelma programm ta 'pproċessar inti stajt qatt jintużaw. 592 00:27:51,880 --> 00:27:55,174 Iżda r-realtà hija li inti m'għandekx tuża verament xi waħda minn dawk il-programmi. 593 00:27:55,174 --> 00:27:57,840 Inti żgur m'għandekx tuża xi ħaġa bħal Microsoft Word, li 594 00:27:57,840 --> 00:28:01,120 għandu jiffaċċjaw grassa u korsiva, u fonts akbar u fonts iżgħar, 595 00:28:01,120 --> 00:28:03,560 minħabba li l-kompjuter ma kura dwar kwalunkwe ta 'dak. 596 00:28:03,560 --> 00:28:05,600 Kollha l-kompjuter huwa ser jimpurtahom huwa 597 00:28:05,600 --> 00:28:09,040 Ingliż bħal struzzjonijiet miktuba fil C. 598 00:28:09,040 --> 00:28:12,050 >> Allura dak li aħna ser nagħmlu ġewwa tal-Appliance CS50 599 00:28:12,050 --> 00:28:14,290 hija tuża programm liberament disponibbli, u huwa 600 00:28:14,290 --> 00:28:17,360 installat minn qabel f'dan appliance, imsejħa gedit. 601 00:28:17,360 --> 00:28:22,280 U gedit huwa biss sempliċi super test editur bħal TextEdit Mac OS, 602 00:28:22,280 --> 00:28:26,200 bħal Windows notepad li għaddej biex tfittex ftit xi ħaġa bħal din. 603 00:28:26,200 --> 00:28:28,910 >> Mela ejja fil-fatt mhux tħares lejn slides ta 'dan. 604 00:28:28,910 --> 00:28:32,580 Imma ejja fil-fatt imorru fis l-ambjent innifsu. 605 00:28:32,580 --> 00:28:36,090 Jien ser jimxi 'l quddiem u log, f'dan tieqa oħra, 606 00:28:36,090 --> 00:28:40,910 li CS50 Appliance tiegħi, li jiena stajt installat minn qabel fuq laptop tiegħi hawn. 607 00:28:40,910 --> 00:28:43,771 >> Avviż li, bħall-Windows u Mac OS, huwa ltqajna xi menus. 608 00:28:43,771 --> 00:28:45,520 Bħal Windows li tqiegħed l-isfel hemm minflok 609 00:28:45,520 --> 00:28:47,020 tal Mac OS, li jpoġġi l-isfel hemmhekk. 610 00:28:47,020 --> 00:28:48,930 Iżda r-realtà hija li huwa kull tip ta 'l-istess. 611 00:28:48,930 --> 00:28:50,770 U fil hawn hija kollha kemm hi mazz ta 'software. 612 00:28:50,770 --> 00:28:51,770 Hemm Dropbox. 613 00:28:51,770 --> 00:28:54,780 Hemm mazz sħiħ ta 'aċċessorji, programmi grafika li aħna ser 614 00:28:54,780 --> 00:28:56,430 użu aktar tard fit-terminu għal settijiet problema. 615 00:28:56,430 --> 00:28:59,650 Hemm web browser mibnija hekk li dan huwa kompjuter żviluppata sħiħa 616 00:28:59,650 --> 00:29:01,240 ġewwa ta 'kompjuter. 617 00:29:01,240 --> 00:29:04,170 >> Imma jien ser ikklikkja dan leftmost ikona abjad hawn, 618 00:29:04,170 --> 00:29:05,890 li hija l-ikona għall gedit. 619 00:29:05,890 --> 00:29:09,650 U li għaddej biex tiftaħ tieqa li għandha tliet panels lilha, 620 00:29:09,650 --> 00:29:12,590 waħda xellug, wieħed mill-quċċata, u waħda qiegħ. 621 00:29:12,590 --> 00:29:16,071 >> Issa huwa f'dan il-wieħed dritt top li Jien ser attwalment jikteb xi kodiċi. 622 00:29:16,071 --> 00:29:16,820 Mela ejja tagħmel dan ,. 623 00:29:16,820 --> 00:29:19,040 Jien se jmorru File, Save. 624 00:29:19,040 --> 00:29:22,100 U inti tista 'ma qatt raw dan il-tieqa partikolari qabel. 625 00:29:22,100 --> 00:29:23,620 Imma dan huwa simili Mac OS jew Windows. 626 00:29:23,620 --> 00:29:25,490 Huwa biss tieqa kollha tal-folders 627 00:29:25,490 --> 00:29:27,290 li għandi ġewwa ta 'dan il-kompjuter. 628 00:29:27,290 --> 00:29:30,320 >> U jien ser tiffranka il-fajl bħala hello.c. 629 00:29:30,320 --> 00:29:32,690 U jien se jmorru quddiem u kklikkja Save. 630 00:29:32,690 --> 00:29:36,364 U issa avviż għandi tab fil-quċċata xellug imsejħa hello.c. 631 00:29:36,364 --> 00:29:38,280 Allura probabbilment pretty familjari, anki jekk inti stajt ma 632 00:29:38,280 --> 00:29:40,240 użat dan il-programm partikolari qabel. 633 00:29:40,240 --> 00:29:44,890 >> U issa jien se tip fil dawk sekwenza pjuttost mistur ta 'kmandi 634 00:29:44,890 --> 00:29:46,360 li rajna mument ilu. 635 00:29:46,360 --> 00:29:49,330 Inkludi, I standard / O.h. 636 00:29:49,330 --> 00:29:50,600 Aktar dwar dan dalwaqt. 637 00:29:50,600 --> 00:29:55,670 Null prinċipali Int, kaboċċi miftuħa Brace, magħluqa kaboċċi Brace. 638 00:29:55,670 --> 00:30:01,570 U allura ġewwa li jkun hemm naħseb huwa fejn kellna "bonjour dinja," virgola. 639 00:30:01,570 --> 00:30:03,100 U issa jiffrankaw. 640 00:30:03,100 --> 00:30:08,780 >> Allura dan huwa programm miktub fis-C, miktub, għalhekk, fil-kodiċi tas-sors. 641 00:30:08,780 --> 00:30:10,720 Imma ma nistax biss run dan il-programm. 642 00:30:10,720 --> 00:30:13,390 I tip ta 'tixtieq li doppja ikklikkja fuq 'ikona x'imkien, 643 00:30:13,390 --> 00:30:16,390 iżda l-ebda icon jeżisti oħra mill-fajl kodiċi sors. 644 00:30:16,390 --> 00:30:20,359 Liema, għal darb'oħra, huwa l-proċess issa li I bżonn biex imexxu dan il-fajl permezz? 645 00:30:20,359 --> 00:30:21,150 UDJENZA: kompilatur. 646 00:30:21,150 --> 00:30:22,399 DAVID J. Malan: Allura kompilatur. 647 00:30:22,399 --> 00:30:24,890 Allura fil-kompjuters differenti inti tagħmel dan b'modi differenti. 648 00:30:24,890 --> 00:30:27,480 Imma dak li aħna ghamilt hawn fil l-Appliance CS50 thats 649 00:30:27,480 --> 00:30:31,260 rappreżentant ta 'kif inti tista tagħmel dan fuq is-sistemi differenti ħafna, 650 00:30:31,260 --> 00:30:34,036 hija Jien sempliċiment ser run kmand imsejħa make. 651 00:30:34,036 --> 00:30:35,660 U Make hu litteralment se tagħmel dan. 652 00:30:35,660 --> 00:30:36,640 Agħmel me a program. 653 00:30:36,640 --> 00:30:39,060 >> Sabiex tagħmel huwa se run kompilatur għalija. 654 00:30:39,060 --> 00:30:42,160 U l-isem tal-programm I tixtieq li tagħmel huwa bonjour. 655 00:30:42,160 --> 00:30:43,510 Issa jagħmlu huwa programm. 656 00:30:43,510 --> 00:30:47,170 U jagħmlu huwa intelliġenti biżżejjed biex jirrealizzaw li jekk ngħid jagħmlu hello, 657 00:30:47,170 --> 00:30:50,980 li għaddej biex tfittex awtomatikament għal fajl imsejjaħ hello.c 658 00:30:50,980 --> 00:30:53,420 biss minħabba dak l- mod huwa konfigurati. 659 00:30:53,420 --> 00:31:00,300 >> Allura meta I issa hit Ikteb hawn, dan linja cryptic crazy biss ltqajna esegwiti. 660 00:31:00,300 --> 00:31:02,720 U trust me, qabel twil, fi żmien ftit jiem, 661 00:31:02,720 --> 00:31:05,590 inti ser tifhem dak kollu ta dak il-mezz nonsense. 662 00:31:05,590 --> 00:31:11,150 Iżda għal issa, biss jafu li jagħmlu eżekuzzjoni attivata ta kompilatur. 663 00:31:11,150 --> 00:31:13,290 Fi kliem ieħor, hija kkonstatat kompilatur fuq il-kompjuter tiegħi 664 00:31:13,290 --> 00:31:14,820 li l-pre-installat fuq il-Appliance CS50 665 00:31:14,820 --> 00:31:16,560 li aħna ser idejn li inti fil Problema Set 1. 666 00:31:16,560 --> 00:31:20,990 U mbagħad ħa hello.c bħala input, u prodotti apparentement 667 00:31:20,990 --> 00:31:23,040 0s u 1s bħala output. 668 00:31:23,040 --> 00:31:29,410 >> U fil-kontumaċja dak li tagħmel huwa li jiffranka dawk 0s u 1s fil-fajl imsejjaħ bonjour. 669 00:31:29,410 --> 00:31:33,180 U għalkemm dan sintassi jista wisq jkun ġdida għalik, sempliċiment billi qal dot 670 00:31:33,180 --> 00:31:37,110 mmejla bonjour se tkun l- Mezz li permezz tiegħu I run dan il-programm. 671 00:31:37,110 --> 00:31:40,360 >> Għal issa u għal mill-inqas ftit ta 'ġimgħat, kważi kollha tal-programmi 672 00:31:40,360 --> 00:31:44,230 aħna tikteb ser ikunu fl twieqi test iswed u abjad. 673 00:31:44,230 --> 00:31:47,006 Nru ġrieden, ebda tikklikkja, ebda twieqi, l-ebda ikoni. 674 00:31:47,006 --> 00:31:49,630 Aħna ser jżommha sempliċi u tiffoka fuq l-ideat sottostanti 675 00:31:49,630 --> 00:31:52,490 inizjalment qabel we nikseb għal xi ħaġa livell ogħla, per eżempju, 676 00:31:52,490 --> 00:31:56,410 bħall-break out logħba li tkellimna dwar fl-ewwel lecture aħħar ġimgħa. 677 00:31:56,410 --> 00:32:00,820 >> Allura meta I hit Ikteb hawn, huwa ekwivalenti f'test biss ambjent 678 00:32:00,820 --> 00:32:03,272 li tirdoppja tikklikkja ikona imsejħa bonjour. 679 00:32:03,272 --> 00:32:05,480 X'qed tistenna rieda jiġri meta I hit Ikteb allura? 680 00:32:05,480 --> 00:32:07,120 >> UDJENZA: Hija ser jistampaw "bonjour dinja." 681 00:32:07,120 --> 00:32:10,000 >> DAVID J. Malan: Nisperaw se print "Hello dinja." 682 00:32:10,000 --> 00:32:11,370 U tabilħaqq għamlet. 683 00:32:11,370 --> 00:32:13,690 Issa hemm kien xi sintassi cryptic hawn. 684 00:32:13,690 --> 00:32:15,950 Ejja kontrina għal ftit mument u ara jekk irridu 685 00:32:15,950 --> 00:32:19,530 ma jistax jibda jiddeduċi biss billi tbagħbis, jippruvaw u fin-nuqqas, 686 00:32:19,530 --> 00:32:21,130 dwar x'inhu għaddej hawn. 687 00:32:21,130 --> 00:32:23,609 X'jiġri jekk I jeħles mill-n backslash? 688 00:32:23,609 --> 00:32:25,650 Issa xi wħud minnkom li stajt programmati qabel probabbilment 689 00:32:25,650 --> 00:32:27,054 taf istantanjament dak li tfisser. 690 00:32:27,054 --> 00:32:29,220 Iżda għal dawk minnkom li stajt qatt programmati qabel, 691 00:32:29,220 --> 00:32:34,052 inqas taħseb li inti stess x'inhu għaddej għall-bidla meta I terġa 'ssir dan il-programm? 692 00:32:34,052 --> 00:32:37,010 So jien se jmorru lura għal tiegħi iswed u abjad tieqa ftit, li 693 00:32:37,010 --> 00:32:39,290 hija l-tieqa li fiha I jistgħu jikkompilaw dan. 694 00:32:39,290 --> 00:32:41,130 Jien ser recompile bonjour. 695 00:32:41,130 --> 00:32:43,520 Aħna qed tmur biex tara l-istess sekwenza cryptic ta jikkmanda. 696 00:32:43,520 --> 00:32:45,719 U jien ser tagħmel dot mmejla bonjour. 697 00:32:45,719 --> 00:32:48,260 U issa xi ħadd, jekk inti, li qatt ma programmati qabel, 698 00:32:48,260 --> 00:32:49,770 dak li jista 'jkun differenti dan iż-żmien? 699 00:32:49,770 --> 00:32:50,020 Yeah. 700 00:32:50,020 --> 00:32:51,840 >> UDJENZA: Dan mhux se tieqaf istampar "dinja bonjour." 701 00:32:51,840 --> 00:32:52,660 >> DAVID J. Malan: Huwa ser to-- sorry? 702 00:32:52,660 --> 00:32:54,210 >> UDJENZA: Dan mhux se tieqaf istampar dan? 703 00:32:54,210 --> 00:32:55,810 >> DAVID J. Malan: Dan mhux se stop-istampar "bonjour dinja." 704 00:32:55,810 --> 00:32:56,560 Allura mhux idea ħażina. 705 00:32:56,560 --> 00:32:58,633 Ideat oħra? 706 00:32:58,633 --> 00:32:59,132 Yeah. 707 00:32:59,132 --> 00:33:00,060 >> UDJENZA: Error messaġġ? 708 00:33:00,060 --> 00:33:01,750 >> DAVID J. Malan: Error messaġġ, OK, jista 'jkun. 709 00:33:01,750 --> 00:33:02,250 X'aktar? 710 00:33:02,250 --> 00:33:05,479 UDJENZA: Jista jistampaw il- parentesi bil-virgola kif ukoll? 711 00:33:05,479 --> 00:33:08,270 DAVID J. Malan: Jista jistampaw il- parentesi bil-virgola ukoll. 712 00:33:08,270 --> 00:33:11,950 Allura forsi li backslash allura hija xi tip ta 'istess affarijiet li l-importanti. 713 00:33:11,950 --> 00:33:14,860 Kwalunkwe ħsibijiet oħra? 714 00:33:14,860 --> 00:33:16,412 >> Ideat Allura kollha tajba. 715 00:33:16,412 --> 00:33:18,370 U fil-fatt, li għaddej li jkun messaġġ ta 'żball. 716 00:33:18,370 --> 00:33:20,400 Li probabbilment l-aktar probabbli li tkun ir-risposta b'mod ġenerali 717 00:33:20,400 --> 00:33:22,420 għall-ftit ġimgħat li ġejjin kif aħna jitgħallmu għall-kodiċi hawn. 718 00:33:22,420 --> 00:33:27,680 >> Iżda għal issa ftakar li l-kompjuters biss tagħmel dak li inti jgħidulhom li jagħmlu. 719 00:33:27,680 --> 00:33:30,400 Ħafna bħall-karawett redikoli butir u l-eżempju jelly. 720 00:33:30,400 --> 00:33:33,860 Kompjuters tal-bniedem tagħna kienu suppost biss biex jagħmlu dak li inti qaltilhom biex jagħmlu. 721 00:33:33,860 --> 00:33:36,250 Allura f'dan il-każ, jekk inti ma jgħidux il-kompjuter 722 00:33:36,250 --> 00:33:41,190 li jiċċaqalqu li cursor Teptip għall- linja li jmiss, mhuwiex ser tagħmel dan. 723 00:33:41,190 --> 00:33:45,390 Allura meta I run dan il-programm issa, avviż-differenza. 724 00:33:45,390 --> 00:33:46,900 >> Jistenna bħal bug. 725 00:33:46,900 --> 00:33:49,190 Huwa ta 'bug estetika, forsi. 726 00:33:49,190 --> 00:33:53,310 Imma dak li hu differenti dwar dan output versus l-aħħar wieħed ovvjament? 727 00:33:53,310 --> 00:33:53,810 Yeah. 728 00:33:53,810 --> 00:33:54,920 >> UDJENZA: Hija ma tagħmel linja ġdida. 729 00:33:54,920 --> 00:33:56,586 >> DAVID J. Malan: Hija ma tagħmel linja ġdida. 730 00:33:56,586 --> 00:33:58,740 Issa dawk minnkom li jkollhom paġni web forsi magħmula 731 00:33:58,740 --> 00:34:01,910 qabel, inti tista 'taf ta' l- Tag BR jew il-paragrafu tikketta, 732 00:34:01,910 --> 00:34:03,120 simili ħafna fl-ispirtu. 733 00:34:03,120 --> 00:34:06,680 A web browser se jinjora inti sakemm inti tgħid eżattament x'għandhom jagħmlu. 734 00:34:06,680 --> 00:34:10,020 Bl-istess mod, hija lingwa bħal C biss se tagħmel dak li inti tgħid li tagħmel. 735 00:34:10,020 --> 00:34:12,730 >> Allura l-raġuni li kollha ta 'dawn l-eżempji, 736 00:34:12,730 --> 00:34:15,350 s'issa, ikollhom tip ta ' każwali kellha din backslash 737 00:34:15,350 --> 00:34:18,560 fil hemm, li l-mezzi li permezz tiegħu inti tesprimi ruħek 738 00:34:18,560 --> 00:34:21,380 bħala karattru linja ġdida, biex ngħidu hekk. 739 00:34:21,380 --> 00:34:26,219 U inti tista 'tip ta' japprezzaw, forsi, li dan look tip ta 'stupid 740 00:34:26,219 --> 00:34:27,070 jekk xejn. 741 00:34:27,070 --> 00:34:29,150 Jekk jien ridt linja ġdida, just laqtu Ikteb u mbagħad it-tip 742 00:34:29,150 --> 00:34:32,219 tal butchering-kodiċi bħal dik m'għandux verament togħrok inti l-mod id-dritt. 743 00:34:32,219 --> 00:34:33,830 U anki jekk inti ma verament kura f'dan il-punt, 744 00:34:33,830 --> 00:34:35,830 inti se tirrealizza li din mhix partikolarment 745 00:34:35,830 --> 00:34:37,870 tajba biċċa tħares 'kodiċi. 746 00:34:37,870 --> 00:34:39,969 >> U hekk dak id-dinja snin deċiżi ilu huwa 747 00:34:39,969 --> 00:34:43,420 li meta inti tixtieq li tqiegħed il- cursor fuq linja ġdida espliċitament, 748 00:34:43,420 --> 00:34:46,332 inti trid espliċitament say linja l-ġdida, backslash n. 749 00:34:46,332 --> 00:34:48,040 U hemm xi oħra simboli bħal dik. 750 00:34:48,040 --> 00:34:50,719 Iżda għal issa aħna ser biss tiffoka fuq backslash n. 751 00:34:50,719 --> 00:34:53,790 >> Issa ejja jagħmlu l-programm ftit aktar interessanti. 752 00:34:53,790 --> 00:34:59,200 Jien ser jimxi 'l quddiem u din id-darba jiftħu fajl ġdid. 753 00:34:59,200 --> 00:35:02,520 Jien ser tiffranka dan bħala bonjour-1.c. 754 00:35:02,520 --> 00:35:05,540 U biss għall kicks, jien ser mur poġġih fil-folder Dropbox tiegħi. 755 00:35:05,540 --> 00:35:09,030 >> Kif tkun taf tara fil-CS50 dokumentazzjoni għall-appliance, 756 00:35:09,030 --> 00:35:11,210 aktar tard din il-ġimgħa għall-Problema Set 1, aħna ser jinkoraġġixxu 757 00:35:11,210 --> 00:35:13,230 biex tuża Dropbox jew xi servizz ekwivalenti, 758 00:35:13,230 --> 00:35:15,430 għaliex imbagħad kollha tal-kodiċi tal tiegħek ser tkun appoġġjata awtomatikament. 759 00:35:15,430 --> 00:35:17,830 U hekk hu għalhekk li stajt marret fis this folder hawn. 760 00:35:17,830 --> 00:35:20,230 >> U issa jien ser jiktbu programm kemmxejn differenti. 761 00:35:20,230 --> 00:35:24,740 Inkludi, I standard / O.h, null prinċipali int. 762 00:35:24,740 --> 00:35:29,660 U mbagħad fil hawn printf, bonjour dinja, li huwa eżattament l-istess bħal qabel. 763 00:35:29,660 --> 00:35:32,450 >> Imma issa nixtieq li jistampaw xi ħaġa thats ftit differenti. 764 00:35:32,450 --> 00:35:34,800 Irrid li jistampa, jgħidu, "Hello, David." 765 00:35:34,800 --> 00:35:37,590 Kull dritt, hekk ovvjament, suppost nisperaw 766 00:35:37,590 --> 00:35:40,360 jkun il-każ li jekk I recompile dan il-programm, terġa 'ssir it, 767 00:35:40,360 --> 00:35:41,840 li għaddej biex jgħidu "bonjour, David." 768 00:35:41,840 --> 00:35:45,160 >> Imma x'jiġri jekk nixtieq li jintroduċu dan it-tip ta 'varjabbli, 769 00:35:45,160 --> 00:35:49,240 il-kunċett ta 'kontenitur li għaddej li jaħżen D-a-vs-i-d u kodiċi mhux diffiċli 770 00:35:49,240 --> 00:35:50,600 fil-programm tiegħi. 771 00:35:50,600 --> 00:35:53,430 Ukoll dak li jekk nibda tagħmel xi ħaġa bħal din? 772 00:35:53,430 --> 00:35:57,120 >> String i, hekk din hija varjabbli. 773 00:35:57,120 --> 00:36:00,250 Jekk inti tixtieq a string, a.k.a. kelma jew frażi. 774 00:36:00,250 --> 00:36:03,485 A sekwenza ta 'karattri huwa dak aħna fl-ipprogrammar sejħa string. 775 00:36:03,485 --> 00:36:06,610 Aħna biss se ġenerikament sejħa hija s, għaliex dan huwa isem sempliċi sbieħ. 776 00:36:06,610 --> 00:36:08,010 Imma I jistgħu sejħa hija xejn. 777 00:36:08,010 --> 00:36:12,920 >> Jien se ngħid string s-ugwali kwotazzjoni unquote, "David," virgola. 778 00:36:12,920 --> 00:36:18,330 U issa nixtieq li daħħal D-a-vs i-d fis-dak jien istampar. 779 00:36:18,330 --> 00:36:23,720 U qabel rajna teaser fuq l-iskrin ta 'xi sintassi speċjali 780 00:36:23,720 --> 00:36:26,050 li ppermettew magħna biex sostitut fil-valur. 781 00:36:26,050 --> 00:36:29,250 Liema kienet l-speċjali simbolu slides ftit ilu? 782 00:36:29,250 --> 00:36:30,040 >> Allura fil-mija. 783 00:36:30,040 --> 00:36:33,830 Fiż-żmien li kien fil-mija d għal numru deċimali. 784 00:36:33,830 --> 00:36:35,850 Dan ma verament jidhru li huma rilevanti hawnhekk. 785 00:36:35,850 --> 00:36:38,650 Jinstabx hemm simbolu ieħor fil-mija, 786 00:36:38,650 --> 00:36:42,810 li hija fil-mija s, li stands għal placeholder għal string. 787 00:36:42,810 --> 00:36:49,350 >> Allura issa, ħafna sempliċement, jien se jmorru make-bonjour 1, 788 00:36:49,350 --> 00:36:54,210 għaliex dan il-fajl sejjaħ bonjour-1.c, u hit Ikteb. 789 00:36:54,210 --> 00:36:56,230 U jien invitat up. 790 00:36:56,230 --> 00:36:57,394 X'qed jiġri? 791 00:36:57,394 --> 00:37:00,560 Well, hawn fejn għandna biex jibdew japprezzaw li aħna qed fl dan il-kmand 792 00:37:00,560 --> 00:37:02,810 ambjent linja, dan test biss l-ambjent. 793 00:37:02,810 --> 00:37:06,114 M'hemm l-ebda tikklikkja fuq icons bħal folders dritt issa. 794 00:37:06,114 --> 00:37:07,280 U jaħsbu lura mument ilu. 795 00:37:07,280 --> 00:37:10,740 F'liema folder ma I say I kien iffrankar kodiċi tiegħi? 796 00:37:10,740 --> 00:37:11,657 Allura l-folder Dropbox. 797 00:37:11,657 --> 00:37:12,989 Setgħu ġew imsejħa xejn. 798 00:37:12,989 --> 00:37:14,530 Iżda dan jiġri li għandu jissejjaħ Dropbox. 799 00:37:14,530 --> 00:37:18,380 So I b'xi bżonn biex ikklikkja darbtejn fuq li folder Dropbox sabiex jiksbu 800 00:37:18,380 --> 00:37:21,657 fis dan u jiksbu fuq tiegħi kodiċi imsejjaħ bonjour-1.c. 801 00:37:21,657 --> 00:37:24,490 Fil-fatt, let me imorru quddiem u jimminimizzaw dan il-tieqa għal ftit mument. 802 00:37:24,490 --> 00:37:27,560 Eżatt bħal Windows u Mac OS, hemm folders fil Linux. 803 00:37:27,560 --> 00:37:29,410 Hemm folders fil-Appliance CS50. 804 00:37:29,410 --> 00:37:32,380 Huwa biss id-dritt issa aħna qed konfinament lilna nfusna biex dan l-ambjent it-test. 805 00:37:32,380 --> 00:37:34,700 >> Imma jekk I ikklikkja darbtejn fuq Dropbox, avviż hemm 806 00:37:34,700 --> 00:37:37,210 huwa l-fajl li nixtieq li jikkompilaw. 807 00:37:37,210 --> 00:37:41,430 Imma I bżonn din iswed u abjad tieqa terminal, biex ngħidu hekk. 808 00:37:41,430 --> 00:37:45,750 Imma I bżonn, għalhekk, li jiċċaqalqu f'dak folder jew direttorju. 809 00:37:45,750 --> 00:37:48,290 Allura ftit arcane, iżda inti ser jidraw dan ukoll. 810 00:37:48,290 --> 00:37:50,430 >> Fid-dinja tal-Linux, li għal darb'oħra huwa l-operattiva 811 00:37:50,430 --> 00:37:54,860 sistema aħna qed taħdem ġewwa tal-CS50 Appliance, hemm kmand imsejħa CD. 812 00:37:54,860 --> 00:37:58,310 Li jfisser I tista 'tagħmel CD, spazju, Dropbox. 813 00:37:58,310 --> 00:37:59,900 CD, direttorju bidla. 814 00:37:59,900 --> 00:38:00,400 Dritt. 815 00:38:00,400 --> 00:38:02,890 Lura fil-ġurnata meta n-nies kienu invenzjoni kompjuters u li joperaw 816 00:38:02,890 --> 00:38:05,806 Sistemi bħal dan, huma riedu tip il-keystrokes fewest possibbli. 817 00:38:05,806 --> 00:38:08,760 Allura l-eħfef mod biex jgħidu direttorju bidla kienet CD. 818 00:38:08,760 --> 00:38:13,910 >> Mela jekk jien hit CD, spazju Dropbox, Avviż dak li nbidlet hawnhekk. 819 00:38:13,910 --> 00:38:16,480 Ġewwa tal-parentesi l-appliance huwa tip 820 00:38:16,480 --> 00:38:19,360 ta humoring lili u fakkruha me fejn I am. 821 00:38:19,360 --> 00:38:21,480 Allura l-folder miftuħ huwa Dropbox. 822 00:38:21,480 --> 00:38:24,950 Jekk I issa tip ls għall lista, għal darb'oħra konċiż, 823 00:38:24,950 --> 00:38:27,540 għaliex in-nies ma jridux tip lura fil-ġurnata l-i-s-t. 824 00:38:27,540 --> 00:38:29,300 Allura dawn minflok għamilha ls. 825 00:38:29,300 --> 00:38:30,110 >> Ikteb. 826 00:38:30,110 --> 00:38:35,740 Avviż I tara żewġ affarijiet, bonjour-1.c, u mbagħad dan ħaġa cryptic, 1m sors. 827 00:38:35,740 --> 00:38:38,310 Li jinsab biss tiegħi mod ta 'tgħid kodiċi tas-sors għall-ġimgħa 1 Tnejn. 828 00:38:38,310 --> 00:38:42,020 C'est folder I titniżżel minn Websajt CS50 li għamilt kmieni llum 829 00:38:42,020 --> 00:38:43,990 u biss jitqiegħed fil- appliance bil-quddiem. 830 00:38:43,990 --> 00:38:47,550 >> Iżda għal issa l-unika ħaġa li għandna kura dwar qed tagħmel dan il-programm. 831 00:38:47,550 --> 00:38:50,440 Allura meta I tip make-bonjour 1, Ikteb. 832 00:38:50,440 --> 00:38:51,320 Kkritikat dan. 833 00:38:51,320 --> 00:38:53,060 Xi ħaġa li marret ħażin. 834 00:38:53,060 --> 00:38:54,580 Mela ejja tease dan apparti. 835 00:38:54,580 --> 00:38:58,489 U sfortunatament dan huwa fejn l-affarijiet jiksbu ftit stressanti fl-ewwel, 836 00:38:58,489 --> 00:39:00,280 għall-inqas jekk inti stajt qatt programmati qabel. 837 00:39:00,280 --> 00:39:00,980 >> My god. 838 00:39:00,980 --> 00:39:04,990 I kiteb programm żewġ linja u I jkollhom erba 'linji ta' żbalji. 839 00:39:04,990 --> 00:39:07,180 Allura x'inhu għaddej hawn. 840 00:39:07,180 --> 00:39:11,370 Ewwel u qabel kollox dejjem iscroll lura up u jsibu l-ewwel messaġġ ta 'żball, 841 00:39:11,370 --> 00:39:15,730 għaliex oftentimes kompilaturi biss nikseb konfuż minn dak li inti u I do. 842 00:39:15,730 --> 00:39:17,000 Il-kompilaturi huma pretty dumb. 843 00:39:17,000 --> 00:39:18,360 Huma ser biss tagħmel dak inti jgħidulhom li jagħmlu. 844 00:39:18,360 --> 00:39:21,484 U jekk inti tħawwadhom, dawn qed biss ser tip ta 'tarmi l-idejn tagħhom 845 00:39:21,484 --> 00:39:25,010 u forsi tarmi aktar messaġġi ta 'żball minn huma attwalment rilevanti. 846 00:39:25,010 --> 00:39:26,380 >> Mela ejja nħarsu lejn l-ewwel. 847 00:39:26,380 --> 00:39:27,540 Super cryptic fl-ewwel. 848 00:39:27,540 --> 00:39:31,050 Iżda avviż, hawn l-isem tal- f'fajl li fih I invitat up apparentement. 849 00:39:31,050 --> 00:39:36,570 Kolon 5, kolon 5 ifisser biss fuq linja 5 fil-ħames karattru. 850 00:39:36,570 --> 00:39:39,760 Allura ħames kolonna ta 'karattri, jekk inti se, żball. 851 00:39:39,760 --> 00:39:41,870 Użu ta 'sekwenza identifikatur mhux iddikjarat. 852 00:39:41,870 --> 00:39:43,120 Ridt tfisser n standard? 853 00:39:43,120 --> 00:39:44,850 >> Le, I fisser string. 854 00:39:44,850 --> 00:39:47,640 U allura huwa tip ta ' ikkupjar u pasta 855 00:39:47,640 --> 00:39:50,700 dak I ittajpjat li verament tiġbed tiegħi attenzjoni għal fejn I invitat up. 856 00:39:50,700 --> 00:39:54,260 Allura għal xi raġuni C, jew għall-inqas l-kumpilatur 857 00:39:54,260 --> 00:39:56,470 ma jifhimx il-string kelma. 858 00:39:56,470 --> 00:39:57,890 U dan għaliex għamilna it up. 859 00:39:57,890 --> 00:40:01,440 Allura string ma teżistix fil C. Liema CS50 ma, 860 00:40:01,440 --> 00:40:03,380 għall-ewwel ftit ġimgħat biss tal-klassi, 861 00:40:03,380 --> 00:40:05,700 huwa nipprovdu xi taħriġ roti, biex ngħidu hekk. 862 00:40:05,700 --> 00:40:11,160 U aħna tpoġġi dawn ir-roti ta 'taħriġ ġewwa ta 'fajl speċjali msejħa CS50.h. 863 00:40:11,160 --> 00:40:14,970 >> Allura dan huwa t-tieni tnejn fajl ismijiet li apparentement tintemm fl dot h. 864 00:40:14,970 --> 00:40:16,300 Ejja kontrina. 865 00:40:16,300 --> 00:40:19,360 Printf hija stqarrija jew funzjoni li apparentement prints xi ħaġa 866 00:40:19,360 --> 00:40:20,580 għall-iskrin. 867 00:40:20,580 --> 00:40:23,470 Imma inti ma tara lili jimplimentaw printf, id-dritt. 868 00:40:23,470 --> 00:40:26,360 Snin ilu Xi ħadd implimentati printf. 869 00:40:26,360 --> 00:40:30,420 F'liema fajl would you wager hu jew hi tpoġġi l-implimentazzjoni 870 00:40:30,420 --> 00:40:34,270 għall printf, il-kodiċi għall printf? 871 00:40:34,270 --> 00:40:36,860 >> Fil fajl imsejjaħ standard I / O.h. 872 00:40:36,860 --> 00:40:39,930 Fil-fatt, huwa probabbilment fl żewġ fajls, I standard / O.h, 873 00:40:39,930 --> 00:40:42,650 li stands għall header fajl, u I standard / O.c, 874 00:40:42,650 --> 00:40:44,060 li stands għall-kodiċi sors C. 875 00:40:44,060 --> 00:40:48,220 Allura hu jew hi xi snin ilu plopped il-kodiċi li kiteb fis dan il-fajl 876 00:40:48,220 --> 00:40:51,240 sabiex in-nies bħalna snin wara jistgħu jinkludu dan, 877 00:40:51,240 --> 00:40:53,040 biex ngħidu hekk, fil-programmi tagħna stess. 878 00:40:53,040 --> 00:40:56,320 >> U fil-fatt, dan huwa dak is-sinjal lira segwit mill-kelma jinkludu ma. 879 00:40:56,320 --> 00:41:00,250 Huwa jistenna fuq il-hard drive lokali, isib il-fajl imsejjaħ I standard / O.h, 880 00:41:00,250 --> 00:41:03,840 u mbagħad effettiv kopji u pejsts ġewwa tal-fajl tiegħi stess. 881 00:41:03,840 --> 00:41:07,210 Allura issa program tiegħi jaf kif li jistampaw l-iskrin. 882 00:41:07,210 --> 00:41:11,120 >> Allura billi li l-loġika, fejn huwa string definit? 883 00:41:11,120 --> 00:41:12,260 >> UDJENZA: CS50.h. 884 00:41:12,260 --> 00:41:13,290 >> DAVID J. Malan: CS50.h. 885 00:41:13,290 --> 00:41:15,540 U fil-fatt, dan huwa dak li aħna, il-persunal qalba, għamlu. 886 00:41:15,540 --> 00:41:19,590 Imxejna ivvintat tipi ta 'data ftit, biex ngħidu hekk, bħal string, 887 00:41:19,590 --> 00:41:22,370 minbarra dawk inti nikseb b'xejn, bħal int. 888 00:41:22,370 --> 00:41:26,010 U aħna ser tara oħrajn bħal char għal karattru u ftit aktar. 889 00:41:26,010 --> 00:41:30,670 Ġewwa l CS50.h apparentement huwa mill-inqas xi aċċenn ta 'spag. 890 00:41:30,670 --> 00:41:34,980 >> Allura issa let me imorru quddiem u terġa 'ssir make bonjour-1. 891 00:41:34,980 --> 00:41:37,100 I ser zoom darb'oħra u cross fingers tiegħi. 892 00:41:37,100 --> 00:41:41,370 Issa minn wara li għamlet waħda bidla I fiss aktar affarijiet. 893 00:41:41,370 --> 00:41:42,100 Iżda kkritikat dan. 894 00:41:42,100 --> 00:41:44,290 Aktar percents minn argumenti dejta. 895 00:41:44,290 --> 00:41:45,980 What did I do wrong dan iż-żmien? 896 00:41:45,980 --> 00:41:47,420 >> Allura huwa għadu pjuttost cryptic. 897 00:41:47,420 --> 00:41:51,560 Iżda dan l-iżball huwa fuq linja 7 u l-karattru 21. 898 00:41:51,560 --> 00:41:53,880 Mela ejja tmur tfittex up here. 899 00:41:53,880 --> 00:41:55,350 Huwa ftit sottili. 900 00:41:55,350 --> 00:41:59,167 Imma jekk inti taħseb dwar dak l-ideat fundamentali hawn huma, 901 00:41:59,167 --> 00:42:00,500 forsi nistgħu tease dan apparti. 902 00:42:00,500 --> 00:42:02,300 >> Allura printf huwa l-isem tal-funzjoni. 903 00:42:02,300 --> 00:42:04,960 Parentesi, s'issa, huwa bħad dak li nitfgħu madwar 904 00:42:04,960 --> 00:42:07,005 l-għalf aħna qed tgħaddi bħala inputs għal funzjoni. 905 00:42:07,005 --> 00:42:08,921 Kull dritt, biss konvenzjoni tal-bniedem arbitrarja. 906 00:42:08,921 --> 00:42:09,919 Uża parentesi. 907 00:42:09,919 --> 00:42:12,460 Ġewwa ta 'dawk parentesi konna ġew tqegħid kwotazzjonijiet doppja, 908 00:42:12,460 --> 00:42:14,810 u mbagħad string bħal "bonjour dinja." 909 00:42:14,810 --> 00:42:18,160 >> Iżda f'dak eżempju kmieni ħafna qosor ma nħarsu lejn mal Scratch. 910 00:42:18,160 --> 00:42:22,590 U kellna l-mija d, x'iktar kien ġewwa ta 'dawk parentesi 911 00:42:22,590 --> 00:42:23,730 li I imsejħa out verbalment? 912 00:42:23,730 --> 00:42:24,230 Yeah. 913 00:42:24,230 --> 00:42:28,166 >> UDJENZA: Allura huwa dak li inti qed tieħu [Inaudible] minn ġewwa [inaudible] 914 00:42:28,166 --> 00:42:30,200 liema dawn [inaudible]? 915 00:42:30,200 --> 00:42:31,200 DAVID J. Malan: Eżattament. 916 00:42:31,200 --> 00:42:32,700 Allura kellna l-mija d. 917 00:42:32,700 --> 00:42:36,620 Iżda mbagħad kellna qrib kwotazzjoni, comma, kontro. 918 00:42:36,620 --> 00:42:37,120 Dritt. 919 00:42:37,120 --> 00:42:40,680 Aħna speċifikat dak li rridu biex jagħmlu bħala l-placeholder. 920 00:42:40,680 --> 00:42:44,621 Allura dak li jien ser tagħmel hawnhekk hija comma, dak li tridu lili biex tqiegħed? 921 00:42:44,621 --> 00:42:45,120 UDJENZA: S. 922 00:42:45,120 --> 00:42:46,828 DAVID J. Malan: S, minħabba s f'dan il-każ 923 00:42:46,828 --> 00:42:48,700 huwa l-isem tal-kontenitur tal-ħażna. 924 00:42:48,700 --> 00:42:50,180 Hu l-isem ta 'dak skutella ħġieġ. 925 00:42:50,180 --> 00:42:53,610 Billi qabel kien counter f'dik Eżempju Scratch sempliċi ħarisna lejn. 926 00:42:53,610 --> 00:42:56,630 Allura issa wara li għamlet żewġ bidliet, let me zoom 927 00:42:56,630 --> 00:42:59,800 u jippruvaw darba aktar biex jikkompilaw dan il-programm. 928 00:42:59,800 --> 00:43:01,596 >> Issa nara dik il-linja cryptic. 929 00:43:01,596 --> 00:43:03,470 Imma dak li attwalment l- isem tal-kompilatur. 930 00:43:03,470 --> 00:43:04,886 Clang huwa l-isem tal-kompilatur. 931 00:43:04,886 --> 00:43:07,100 Jagħmlu huwa biss iffrankar me l-uġigħ ta 'ras ta' dejjem 932 00:43:07,100 --> 00:43:09,830 ittajpjar dak il-kmand twil crazy out. 933 00:43:09,830 --> 00:43:14,900 Allura issa jekk I do dot mmejla bonjour-1, I għandhom ara "hello, David." 934 00:43:14,900 --> 00:43:16,450 >> Pretty underwhelming, għalkemm, id-dritt? 935 00:43:16,450 --> 00:43:18,158 Aħna seta 'jsir dan ħafna aktar sempliċement 936 00:43:18,158 --> 00:43:20,940 mingħajr ma tkellem dwar varjabbli u CS50.h u kollha ta 'dak. 937 00:43:20,940 --> 00:43:23,080 Mela ejja jagħmilha ftit aktar interessanti. 938 00:43:23,080 --> 00:43:31,010 >> Minbarra l CS50.h, jkollhom affarijiet simili string 939 00:43:31,010 --> 00:43:34,550 iddikjarat, il-librerija CS50 għandha wkoll ftit funzjonijiet. 940 00:43:34,550 --> 00:43:38,520 Snin Hekk biss bħal ilu, xi ħadd kiteb printf u poġġih fl-istandard I / O.h 941 00:43:38,520 --> 00:43:39,530 u xi fajl ieħor. 942 00:43:39,530 --> 00:43:44,010 >> Aħna, il-persunal CS50, kiteb funzjoni imsejħa getchar, GetDouble, GetFloat, 943 00:43:44,010 --> 00:43:47,610 GetInt, GetLongLong, GetString, u npoġġux dawk ġewwa fajl 944 00:43:47,610 --> 00:43:49,890 imsejħa CS50.h u CS50.c. 945 00:43:49,890 --> 00:43:51,880 U aħna jqiegħdhom ġewwa tal-Appliance CS50. 946 00:43:51,880 --> 00:43:53,880 U n-nies tista 'wkoll tniżżilhom online jekk dawn 947 00:43:53,880 --> 00:43:55,880 tixtieq li jpoġġuhom fuq tagħhom kompjuters stess kif ukoll. 948 00:43:55,880 --> 00:44:00,880 Li huwa li jgħidu li ħloqna funzjonijiet li jiksbu input mill-utent. 949 00:44:00,880 --> 00:44:02,930 I do not know dak kollu ta 'din id-data it-tipi huma. 950 00:44:02,930 --> 00:44:06,490 GetInt huwa tip ta 'sempliċi, bħal tikseb integer b'xi mod mill-utent. 951 00:44:06,490 --> 00:44:09,980 U GetString huwa probabbilment bħal get kelma jew sentenza mill-utent. 952 00:44:09,980 --> 00:44:11,770 >> Mela ejja tiffoka fuq dan. 953 00:44:11,770 --> 00:44:14,710 U jien se jmorru lura fil- appliance u jien ser jimxi 'l quddiem 954 00:44:14,710 --> 00:44:20,790 u ħlief dan il-fajl bħala, ejja sejħa it bonjour-2.c bħala t-tieni verżjoni tiegħi. 955 00:44:20,790 --> 00:44:23,030 U ejja jagħmlu koppja ta 'bidliet. 956 00:44:23,030 --> 00:44:25,800 >> Din id-darba minflok hard David kodifikazzjoni, li 957 00:44:25,800 --> 00:44:29,120 jagħmel oerhört konsistenti imma programm underwhelming, 958 00:44:29,120 --> 00:44:32,640 jekk dak I minflok do GetString? 959 00:44:32,640 --> 00:44:35,660 Issa avviż GetString għandha parentesi miftuħa, 960 00:44:35,660 --> 00:44:38,500 parentesi magħluqa, minħabba ma bżonn xi input. 961 00:44:38,500 --> 00:44:40,850 Huwa biss se jmorru tikseb string mill-utent. 962 00:44:40,850 --> 00:44:42,460 >> U issa kelma fuq sintassi oħra. 963 00:44:42,460 --> 00:44:45,439 Semicolons biss jispiċċaw linja ta 'kodiċi. 964 00:44:45,439 --> 00:44:46,730 Inti ma għandekx bżonn minnhom kullimkien. 965 00:44:46,730 --> 00:44:48,896 Iżda dan ifisser biss jien isir ma din il-linja tal-kodiċi. 966 00:44:48,896 --> 00:44:51,080 Let me jimxu fuq ieħor dikjarazzjoni jew il-funzjoni. 967 00:44:51,080 --> 00:44:53,010 String tiddikjara varjabbli. 968 00:44:53,010 --> 00:44:55,920 String huwa simili qal tagħti me a bowl, jekk jogħġbok. 969 00:44:55,920 --> 00:44:57,940 U let me tpoġġi string fiha. 970 00:44:57,940 --> 00:44:59,430 >> U issa l-sinjal ugwali. 971 00:44:59,430 --> 00:45:03,510 X'inhu l-sinjal ugwali essenzjalment ekwivalenti għal? 972 00:45:03,510 --> 00:45:04,500 >> UDJENZA: Jassenja. 973 00:45:04,500 --> 00:45:06,190 >> DAVID J. Malan: Yeah, assenjazzjoni ta 'valur. 974 00:45:06,190 --> 00:45:09,872 Mela jekk jien, per eżempju, is-sejħa dan GetString funzjoni, 975 00:45:09,872 --> 00:45:12,830 u aħna ser tara fil-mument li l- ser pront l-utent għal string. 976 00:45:12,830 --> 00:45:17,810 Dan huwa simili kiri me imbagħad jiktbu -D a-vs i-d fuq biċċa karta. 977 00:45:17,810 --> 00:45:21,060 U meta ngħid string i ugwali GetString, 978 00:45:21,060 --> 00:45:24,140 ugwali ma jfissirx verament ugwali fl-ipprogrammar C. 979 00:45:24,140 --> 00:45:27,880 Dan ifisser jassenja mid-dritt naħa l-naħa tax-xellug. 980 00:45:27,880 --> 00:45:29,510 >> So I ve gotten string. 981 00:45:29,510 --> 00:45:32,785 U s-sinjal ugwali jfisser poġġih fil-ħażna kontenitur imsejħa s. 982 00:45:32,785 --> 00:45:36,730 U Imbagħad jgħaddu dan off biex printf li fil-fatt jagħmlu ħaġa tagħha. 983 00:45:36,730 --> 00:45:39,790 >> Allura l-riżultat aħħari mbagħad huwa għaddej biex tfittex ftit differenti. 984 00:45:39,790 --> 00:45:40,840 Ejja nagħmlu make-bonjour 2. 985 00:45:40,840 --> 00:45:43,940 986 00:45:43,940 --> 00:45:45,260 Jew jistgħu jaħdmu. 987 00:45:45,260 --> 00:45:46,450 Inti wara flimkien. 988 00:45:46,450 --> 00:45:47,940 Make-bonjour 2 maħduma. 989 00:45:47,940 --> 00:45:52,640 Dot mmejla bonjour-2, Ikteb. 990 00:45:52,640 --> 00:45:54,620 >> I jidhru li jkollhom infinita loop jew xi ħaġa. 991 00:45:54,620 --> 00:45:55,453 Xejn jiġri. 992 00:45:55,453 --> 00:45:56,134 Għaliex? 993 00:45:56,134 --> 00:45:57,805 >> UDJENZA: Huwa tagħmel loop infinita. 994 00:45:57,805 --> 00:45:59,430 DAVID J. Malan: Huwa loop infinita. 995 00:45:59,430 --> 00:46:02,710 Huwa tip ta 'stennija għalija li attwalment jipprovdih bl xi kontribut. 996 00:46:02,710 --> 00:46:05,800 So let me jimxi 'l quddiem u t-tip fl David, u hit Ikteb. 997 00:46:05,800 --> 00:46:07,230 U issa jgħid "hello, David." 998 00:46:07,230 --> 00:46:09,040 Jekk I run mill-ġdid. 999 00:46:09,040 --> 00:46:11,530 Ejja tip fil Rob, "hello, Rob." 1000 00:46:11,530 --> 00:46:13,900 >> Issa dan huwa l-agħar user interface qatt. 1001 00:46:13,900 --> 00:46:16,110 L-utent huwa apparentement suppost li tkun taf x'għandek tagħmel. 1002 00:46:16,110 --> 00:46:17,120 Imma ma jimpurtax. 1003 00:46:17,120 --> 00:46:19,570 Jużaw dawn istess bini blokki bħad fil Scratch, 1004 00:46:19,570 --> 00:46:24,980 nistgħu issolvi din il-problema u jgħidu xi ħaġa bħal isem tiegħek jekk jogħġbok, kolon, 1005 00:46:24,980 --> 00:46:27,820 ispazju, magħluqa kwotazzjoni, qrib parentesi, virgola. 1006 00:46:27,820 --> 00:46:30,680 Allura ħafna darb'oħra silliness mal-sintassi. 1007 00:46:30,680 --> 00:46:34,040 >> Imma avviż Stajt biss miżjud biċċa puzzle hawn fuq dan wieħed 1008 00:46:34,040 --> 00:46:35,280 u fuq dan wieħed. 1009 00:46:35,280 --> 00:46:38,870 Allura issa jekk jien terġa dan, bonjour-2, Ikteb. 1010 00:46:38,870 --> 00:46:41,180 Stenna minuta. 1011 00:46:41,180 --> 00:46:41,830 X'hemm ħażin? 1012 00:46:41,830 --> 00:46:43,570 Mhuwiex iġibu ruħhom b'mod differenti. 1013 00:46:43,570 --> 00:46:44,200 Yeah. 1014 00:46:44,200 --> 00:46:46,010 >> UDJENZA: Inti ma run jagħmlu mill-ġdid. 1015 00:46:46,010 --> 00:46:47,968 >> DAVID J. Malan: I ma run jagħmlu darb'oħra, id-dritt. 1016 00:46:47,968 --> 00:46:49,430 So I ve mibdula kodiċi sors tiegħi. 1017 00:46:49,430 --> 00:46:50,638 Iżda għal darb'oħra, hemm li l-fluss. 1018 00:46:50,638 --> 00:46:54,530 Kodiċi tas-sors permezz tal-kumpilatur jagħti inti kodiċi l-ġdid oġġett, jew 0s u 1s. 1019 00:46:54,530 --> 00:47:00,209 So I bżonn biex attwalment terġa 'ssir make bonjour-2 Ikteb. 1020 00:47:00,209 --> 00:47:01,750 OK, xi ħaġa jidher li ġara. 1021 00:47:01,750 --> 00:47:04,220 Dot mmejla bonjour-2. 1022 00:47:04,220 --> 00:47:05,390 Ismek jekk jogħġbok. 1023 00:47:05,390 --> 00:47:09,990 U biex ikunu ċari issa, għaliex hija il-cursor fuq l-istess linja? 1024 00:47:09,990 --> 00:47:10,490 Eżattament. 1025 00:47:10,490 --> 00:47:13,020 I ma poġġiex il-backslash n up hawn fil-kodiċi tiegħi. 1026 00:47:13,020 --> 00:47:16,110 Allura issa I tista 'tikteb xi ħaġa bħal Daven, Ikteb. 1027 00:47:16,110 --> 00:47:18,710 I tista 'taħdem mill-ġdid u t-tip xi ħaġa bħal Gabe, Ikteb, 1028 00:47:18,710 --> 00:47:22,250 u nikbru programm differenti ġdid u għal darb'oħra u għal darb'oħra. 1029 00:47:22,250 --> 00:47:28,940 >> Issa finalment aħna qed tmur għall-ħtieġa biex jużaw kapaċitajiet differenti ftit. 1030 00:47:28,940 --> 00:47:32,860 Għandna bżonn li jiġu introdotti finalment xi kundizzjonijiet biex tagħmel affarijiet kundizzjonalment. 1031 00:47:32,860 --> 00:47:35,550 Forsi loops hekk nistgħu nagħmlu affarijiet u għal darb'oħra. 1032 00:47:35,550 --> 00:47:38,220 >> Forsi jkun sbieħ jekk aħna jista 'jimplimenta l-funzjonijiet tagħna stess, 1033 00:47:38,220 --> 00:47:41,355 bħal aħna jista 'jimplimenta tagħna stess printf jew il-verżjoni tagħna stess ta 'GetString 1034 00:47:41,355 --> 00:47:45,870 u GetFlow, għaliex finalment anke jużaw dan l-ambjent linja tal-kmand 1035 00:47:45,870 --> 00:47:49,780 nistgħu nagħmlu anke l-aktar viżwalment interessanti ta 'affarijiet. 1036 00:47:49,780 --> 00:47:51,950 >> Tabilħaqq fil-konklużjoni let me tagħmel dan. 1037 00:47:51,950 --> 00:47:54,020 Jien ser jimxi 'l quddiem u qrib dawn it-twieqi 1038 00:47:54,020 --> 00:47:57,400 u tiftaħ din l-ikona hawn, li huwa biss akbar 1039 00:47:57,400 --> 00:48:00,020 verżjoni ta 'dak inkorporat tieqa terminal. 1040 00:48:00,020 --> 00:48:02,329 Allura gedit mhux biss il-post għall-kodiċi tiegħi, 1041 00:48:02,329 --> 00:48:05,620 iżda wkoll mibnija tieqa terminal, il- tieqa iswed u abjad fejn I tista 'taħdem 1042 00:48:05,620 --> 00:48:06,230 jikkmanda. 1043 00:48:06,230 --> 00:48:08,600 >> I biss ġara li tiftaħ verżjoni akbar ta 'dan. 1044 00:48:08,600 --> 00:48:11,170 U issa jien se jmorru fil l-folder li stajt diġà 1045 00:48:11,170 --> 00:48:13,150 jitqiegħdu bil-quddiem fuq il-websajt il-kors tal-. 1046 00:48:13,150 --> 00:48:16,720 U jien ser jimxi 'l quddiem u tiftaħ fajl imsejjaħ thadgavin.c, 1047 00:48:16,720 --> 00:48:18,710 li ġie miktub minn xi ħadd ieħor. 1048 00:48:18,710 --> 00:48:21,220 >> U jekk inħarsu lejn din, dan mhuwiex it-tip ta 'kodiċi 1049 00:48:21,220 --> 00:48:24,370 aħna ser tkun bil-miktub mill- l-għan ta 'dan il-kodiċi 1050 00:48:24,370 --> 00:48:28,450 kien li jiktbu l-prettiest tfittex kodiċi li hu jew hi tista ', 1051 00:48:28,450 --> 00:48:31,290 irrispettivament minn jekk jew le bniedem ieħor jista 'qatt 1052 00:48:31,290 --> 00:48:33,660 jifhmu dan il-kodiċi. 1053 00:48:33,660 --> 00:48:37,050 >> Tabilħaqq, kull sena jkun hemm x'hemm jissejjaħ konkors C obfuscated, li 1054 00:48:37,050 --> 00:48:39,570 huwa għall geeks reali li jiktbu kodiċi li ebda wieħed inkella jista 'jaqra, 1055 00:48:39,570 --> 00:48:42,050 iżda li ma xi ħaġa jew verament sempliċi jew verament aqwa. 1056 00:48:42,050 --> 00:48:43,890 U ħsibna aħna'd tikkonkludi ma din tfittex 1057 00:48:43,890 --> 00:48:48,300 fuq xi ħaġa li pjuttost aqwa inti tista raw darba qabel. 1058 00:48:48,300 --> 00:48:52,650 Iżda aħna ser jispiċċaw fuq dan nota, dot mmejla, thadgavin. 1059 00:48:52,650 --> 00:48:53,860 Dan imbagħad huwa dak li jistenna. 1060 00:48:53,860 --> 00:48:57,140 1061 00:48:57,140 --> 00:48:58,500 >> C'est għal CS50. 1062 00:48:58,500 --> 00:48:59,935 Aħna se tara int nhar l-Erbgħa. 1063 00:48:59,935 --> 00:49:04,284 1064 00:49:04,284 --> 00:49:10,016 >> [Daqq ta mużika] 1065 00:49:10,016 --> 00:53:31,883