1
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>> [Daqq tal-mużika]

2
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>> DAVID Malan: Kull dritt.

3
00:00:12,830 --> 00:00:13,370
Merħba lura.

4
00:00:13,370 --> 00:00:16,510
Dan huwa CS50, u dan huwa
Ġimgħa waħda, Ikompli.

5
00:00:16,510 --> 00:00:20,050
Allura waħda mir-raġunijiet aħna kont qed tgħaddi
madwar teknoloġiji bħal

6
00:00:20,050 --> 00:00:24,120
Google ħġieġ huwa li dawn jaqgħu mal-
xi ħaġa magħrufa bħala API, l-

7
00:00:24,120 --> 00:00:25,980
Applikazzjoni Programming Interface.

8
00:00:25,980 --> 00:00:28,830
U dak li dan ifisser huwa li bl-
fajls dritt u bid-dritt

9
00:00:28,830 --> 00:00:32,850
dokumentazzjoni, inti tista 'attwalment tikteb
software għal apparati anke bħal dawn.

10
00:00:32,850 --> 00:00:36,200
>> U hekk dak li għandna fil-moħħ lejn
semestri għan huwa, jekk proġett

11
00:00:36,200 --> 00:00:39,310
jinvolvu, ngħidu aħna, Google ħġieġ jista
appell, aħna ser tara dak li nistgħu nagħmlu fl

12
00:00:39,310 --> 00:00:42,220
F'termini ta 'hooking up inti ma' xi
hardware loaner kif ukoll il-

13
00:00:42,220 --> 00:00:46,500
API pubblikament aċċessibbli sabiex inti tista '
attwalment tibda ħolqien software

14
00:00:46,500 --> 00:00:48,630
li timxi fuq l-istess Glass Google.

15
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>> Mezz ieħor li aħna kont qed jilagħbu
ma ta tard li ħsibna jista 'jkun

16
00:00:51,710 --> 00:00:53,910
gost fl-aħħar semestru huwa
dan il-ħaġa ftit hawn.

17
00:00:53,910 --> 00:00:56,860
Huwa sejjaħ Leap Mozzjoni, u dak li int
waslet biex tara hija teknikament

18
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reklam għall-mezz, iżda
ma jitkellmu dwar din partikolari

19
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apparat huwa kapaċi.

20
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U dan, wisq, taqa 'ma' API via
li tista 'tikteb software biex

21
00:01:05,550 --> 00:01:10,545
kontroll tal-kompjuter tiegħek b'mod
pjuttost simili dan il-film ta 'minuta hawn.

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>> [Daqq video]

23
00:01:12,070 --> 00:02:08,002

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>> [Daqq video END]

25
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>> Allura issa dritt, dan il-mezz jiġri li
jiġu implimentati bħala USB ftit

26
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konnettur li inti tista 'plagg fil tiegħek
kompjuter, iżda nixtieq ma jkun sorpriż

27
00:02:14,290 --> 00:02:17,930
jekk qabel twil għandna dawn it-tipi ta '
teknoloġiji fil-lott li jmiss ta 'PCs

28
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u MACs sabiex inti tista ', tabilħaqq,
jinteraġixxu miegħu fl

29
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b'mod bħal dik.

30
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Fil-fatt, dak li ħsibt I d tagħmel, wisq, huwa
I jinġibed up dimostrazzjoni ftit

31
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programm li jiġi ma 'dan is-software.

32
00:02:25,860 --> 00:02:28,700
Allura stajt tpoġġi l-sensor ftit
quddiem ta 'laptop tiegħi.

33
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>> U kif tista 'tara, huwa diġà jirrealizza
li naħa tiegħi hemm

34
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tikkontrollah.

35
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U dan kollu l-applikazzjoni ma huwa
affarijiet swimmingly ftit bħal dan.

36
00:02:37,900 --> 00:02:41,080
Iżda int tista 'tara li, tabilħaqq,
I jkollu ħames swaba hemmhekk.

37
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Jekk nistgħu nibdew li jagħmlu dak kollu 10,
tista 'timmaġina piano pulita

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applikazzjoni jew simili.

39
00:02:45,390 --> 00:02:47,820
Mela jekk inti tixtieq li toħroġ wara klassi
llum u play ma 'dak li

40
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ukoll, inti merħba li.

41
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Allura aktar fuq li lejn tmiem semestru tal.

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>> Allura ftit amministrattiva
Avviżi.

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Wieħed, do taqsima billi dan il-ġimgħa
f'nofsinhar fl cs60.net/section.

44
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Dan URL huwa fuq li l-kors
homepage ukoll.

45
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Fil-frattemp, għalkemm, supersections
se DEBUT dan il-Ħadd.

46
00:03:04,010 --> 00:03:07,800
Supersections huma ħaġa ta 'darba,
minħabba li jieħu us xi żmien biex jaħdmu

47
00:03:07,800 --> 00:03:09,470
min i f'liema taqsima u fejn.

48
00:03:09,470 --> 00:03:12,280
>> Allura dan il-Ħadd li ġejjin, ser ikun hemm wieħed
sezzjoni għal dawk inqas komdi,

49
00:03:12,280 --> 00:03:14,040
sezzjoni waħda għal dawk
aktar komda.

50
00:03:14,040 --> 00:03:16,110
U dawk minnkom x'imkien
bejn are welcome biex tmur

51
00:03:16,110 --> 00:03:17,850
jew it-tnejn jew la.

52
00:03:17,850 --> 00:03:19,150
Kemm minn dawn se jkunu iffilmjati.

53
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Huma ser ikunu sala akbar minn
sezzjoni normalment tkun pulzieri

54
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Iżda l-għan hawnhekk huwa li tgħammar int ma '
xi kumdità ma 'problema sett wieħed,

55
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ma 'C, bl-appliance CS50, dan
weekend, anki qabel ma inti taf tiegħek

56
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assenjazzjoni formali taqsima.

57
00:03:31,050 --> 00:03:34,700
Allura inti ser jiltaqa TF tiegħek u iżgħar tiegħek
grupp ta 'sectionmates f'madwar

58
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żmien ta 'ġimgħa.

59
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>> Ħinijiet tal-uffiċċju, sadanittant,
ġew għaddejjin.

60
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Do jieħdu vantaġġ minnhom tonight jew
għada bil-lejl jekk inti tixtieq.

61
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Sett Problema 0 huwa dovut nhar il-Ġimgħa.

62
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Dan huwa jum aktar tard mid-
regolarment skedata Ħamis.

63
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Iżda bil-problema sett 1, tkun taf tara
li tinkludi xi warm-up

64
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eżerċizzji li inti stess
tista 'testendi tiegħek

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Skadenza-Ħamis sal-Ġimgħa.

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Sett Problem 1, sadanittant, se DEBUT
fuq il-websajt tal-kors ta 'din ġejjin

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Ġimgħa, jekk inti tixtieq li curl bi
huwa kif għamilt darba fuq żmien tard

68
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Ġimgħa bil-lejl fil-kamra tiegħek.

69
00:04:04,370 --> 00:04:07,660
>> Allura cs50.net/appliance huwa l-post fejn
inti tista 'tikseb l-appliance CS50

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li aħna bdew jużaw nhar it-Tnejn.

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Aħna ser tużah daqsxejn aktar illum.

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Iżda mistrieħ assigurat li l-problema stabbilixxa l-1
ispeċifikazzjoni ser jimxu miegħek permezz

73
00:04:14,040 --> 00:04:16,490
preċiż l-passi li għandek bżonn
biex tikseb dan u titħaddem.

74
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Allura ma joqogħdu jinkwetaw dwar kif isir dan qabel
Pset 1 jekk youd pjuttost ma.

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>> Kull dritt.

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00:04:22,660 --> 00:04:27,180
Allura aħna ħares fuq it-Tnejn fil-source code,
iżda fil-kuntest ta 'sistema ġdida

77
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lingwa ta 'programmar, jiġifieri C. And C,
b'differenza Scratch, mhuwiex grafika.

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00:04:30,895 --> 00:04:32,270
Mhuwiex puzzle biċċiet.

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00:04:32,270 --> 00:04:34,450
Huwa aktar English-like sintassi.

80
00:04:34,450 --> 00:04:37,140
U hemm koppja ta 'passi kollha involuti
fil-fatt bil-miktub u tmexxija ta '

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programm C, għaliex minbarra sors
kodiċi bħal dan, għandek bżonn xi ħaġa

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imsejħa kompilatur.

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00:04:42,890 --> 00:04:46,682
U f'termini laymans, dak
ma kompilatur do għalina?

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Yeah.

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>> STUDENT: Hija tikkonverti l-kodiċi
li tikteb biex 0s u 1s.

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>> DAVID Malan: Tajba.

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Allura li tikkonverti l-kodiċi li
aħna jikteb lill 0s u 1s.

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Hija tikkonverti hekk imsejħa kodiċi sors li
kodiċi ta 'oġġett, b'dawn tal-aħħar jistenna

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00:04:57,730 --> 00:04:59,140
ftit xi ħaġa bħal din.

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00:04:59,140 --> 00:05:02,860
U huwa CPU tiegħek, l-imħuħ ġewwa ta
kompjuter tiegħek, li minħabba l-

91
00:05:02,860 --> 00:05:06,280
nies li ħolqu dawn il-kompjuters,
taf liema dawk sekwenzi

92
00:05:06,280 --> 00:05:07,460
tal-medja 0s u 1s.

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>> Forsi dan ifisser print.

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Forsi dan ifisser żieda.

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00:05:10,265 --> 00:05:11,610
Forsi dan ifisser tnaqqis.

96
00:05:11,610 --> 00:05:13,350
Forsi dan ifisser juru grafika.

97
00:05:13,350 --> 00:05:16,870
Hemm mudelli predefiniti ta 'bits
li d-dinja tkun iddeċidiet jfissirx

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00:05:16,870 --> 00:05:17,700
ċerti affarijiet.

99
00:05:17,700 --> 00:05:20,760
Iżda għall-parti l-aktar f'dan il-kors,
aħna ser jaħdem fi grad ogħla, u

100
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aħna ser jieħdu għal mogħtija li jeżistu
affarijiet simili kompilaturi li jistgħu

101
00:05:24,180 --> 00:05:27,670
jagħmlu funzjoni tagħna kodiċi sors
fil-mod kif aħna ħsieb.

102
00:05:27,670 --> 00:05:31,660
>> Allura l-programm aħna kiteb l-ewwel ġimgħa li għaddiet
u mbagħad beda port, biex

103
00:05:31,660 --> 00:05:33,920
jitkellmu, għal dan C passat
It-Tnejn, kien dan.

104
00:05:33,920 --> 00:05:35,700
Meta bandiera aħdar għafast, jgħidu bonjour.

105
00:05:35,700 --> 00:05:37,430
Dan kien, naturalment,
miktuba Scratch.

106
00:05:37,430 --> 00:05:40,710
U jien qal li l-ekwivalenti
programm C ħares ftit

107
00:05:40,710 --> 00:05:41,520
xi ħaġa bħal din.

108
00:05:41,520 --> 00:05:45,050
>> Allura dak li ħsibt aħna'd nagħmlu fil-ewwel huwa,
ejja tease apparti dak li jistenna, fl-ewwel

109
00:05:45,050 --> 00:05:48,790
daqqa t'għajn, ċertament, bħala pjuttost arcane
sintassi, iżda inti ser tibda l-avviż

110
00:05:48,790 --> 00:05:50,160
mudelli pjuttost malajr.

111
00:05:50,160 --> 00:05:53,770
Dak li aħna ser wkoll tagħmel illum huwa jipprovdi
inti ma 'mudell mentali għal xi

112
00:05:53,770 --> 00:05:57,280
canonical, xi constructs standard
fil-programmazzjoni.

113
00:05:57,280 --> 00:06:00,420
U allura aħna ser attwalment jiksbu l-idejn tagħna
maħmuġin b'xi eżempji kif ukoll.

114
00:06:00,420 --> 00:06:04,140
>> Għalhekk għal dawk tal inti aktar komda,
jirrealizzaw li din il-ġimgħa u mbagħad li jmiss

115
00:06:04,140 --> 00:06:05,940
ġimgħa jista 'jkun tajjeb ħafna daqsxejn ta' reviżjoni.

116
00:06:05,940 --> 00:06:08,810
Iżda speċjalment meta l-edizzjoni Hacker
ta 'problema sett 1 tmur fuq il-

117
00:06:08,810 --> 00:06:12,330
website kors nhar il-Ġimgħa, jien naħseb
inti ser issib li anki kif inti timla

118
00:06:12,330 --> 00:06:15,390
xi blanks matul il-ġimgħa d-dieħla jew tnejn,
inti ser tibda tikseb dejjem aktar

119
00:06:15,390 --> 00:06:18,410
ikkontestata u jiltaqgħu
affarijiet ġodda u aktar ġodda.

120
00:06:18,410 --> 00:06:21,310
>> Mela ejja tease apparti dan il-programm
ftit linji fi żmien.

121
00:06:21,310 --> 00:06:24,140
Fuq nett, għandna x'hemm
teknikament jissejjaħ

122
00:06:24,140 --> 00:06:25,950
direttiva Preprocessor.

123
00:06:25,950 --> 00:06:30,510
Dan huwa biss linja tal-kodiċi li tgħid
biex tinkludi l-kontenut ta 'fajl,

124
00:06:30,510 --> 00:06:35,080
imsejħa standard I / N, input standard -
jew, sorry, standard I / O, standard

125
00:06:35,080 --> 00:06:38,670
input / output,. h, ġewwa
tal-programm tiegħi stess.

126
00:06:38,670 --> 00:06:41,670
>> Allura fi kliem ieħor, jekk I kiteb dan
programm bil-editur test sempliċi bħal

127
00:06:41,670 --> 00:06:45,260
gedit, l-ekwivalenti sempliċi ta '
xi ħaġa bħal Microsoft Word, li

128
00:06:45,260 --> 00:06:50,970
istruzzjoni, # jinkludu stdio.h, huwa biss
ser jgħidlek il-kompilatur, grab-

129
00:06:50,970 --> 00:06:56,080
kontenut ta 'dan il-fajl oħra, stdio.h,
u paste dritt hawn.

130
00:06:56,080 --> 00:06:57,090
>> Issa, għaliex għandi kura?

131
00:06:57,090 --> 00:07:01,850
What did aħna pretensjoni hija ġewwa ta 'dan il-fajl
imsejħa stdio.h, li hija maħżuna

132
00:07:01,850 --> 00:07:05,490
x'imkien fuq hard drive tiegħi, jew f'dan
każ, x'imkien fil-appliance CS50?

133
00:07:05,490 --> 00:07:06,635
Xi ħadd ieħor poġġih hemmhekk għalija.

134
00:07:06,635 --> 00:07:09,910
Imma x'hemm dan?

135
00:07:09,910 --> 00:07:13,020
>> Yeah, dan huwa dikjarazzjoni ta '
funzjoni msejħa printf.

136
00:07:13,020 --> 00:07:17,400
Allura printf ifakkar il-funzjoni li
kliem displays u l-karattri u

137
00:07:17,400 --> 00:07:20,160
numri fuq l-iskrin fil-offerti tiegħi.

138
00:07:20,160 --> 00:07:21,220
Imma jien ma jiktbu.

139
00:07:21,220 --> 00:07:22,230
CS50 ma jiktbu dan.

140
00:07:22,230 --> 00:07:26,990
Xi ħadd snin ilu kiteb dan, u dawn
essenzjalment tana l-riċetta għal din

141
00:07:26,990 --> 00:07:29,110
fil-fajl imsejjaħ stdio.h.

142
00:07:29,110 --> 00:07:33,240
Allura li l-ewwel linja biss tagħti me aċċess
għall-funzjonijiet li xi ħadd ieħor

143
00:07:33,240 --> 00:07:36,500
kiteb snin ilu, fost
li huma printf.

144
00:07:36,500 --> 00:07:39,450
>> Issa, il-linja li jmiss jien ser mewġa tiegħi
naħa lejn, mill-inqas sa ġimgħa d-dieħla.

145
00:07:39,450 --> 00:07:43,620
Iżda għal issa, jafu li int prinċipali (vojt) huwa
essenzjalment l-ekwivalenti ta 'dan

146
00:07:43,620 --> 00:07:46,310
biċċa puzzle isfar meta
bandiera aħdar għafast.

147
00:07:46,310 --> 00:07:49,510
Id-dinja, sena ilu, iddeċieda li jekk
int kitba ta 'programm fil-

148
00:07:49,510 --> 00:07:53,150
lingwa imsejħa C, tibda
programm tiegħek ma 'linja

149
00:07:53,150 --> 00:07:54,410
li qisu dan.

150
00:07:54,410 --> 00:07:57,650
Fil biss dwar ħin ta 'ġimgħa, li ser tagħmel
sens dak int hija, dak null hija.

151
00:07:57,650 --> 00:08:00,840
Iżda għal issa, biss jaħsbu li
kif din il-biċċa puzzle isfar.

152
00:08:00,840 --> 00:08:04,550
>> Issa jmiss, għandna Brace kaboċċi segwit
minn ieħor Brace kaboċċi qrib,

153
00:08:04,550 --> 00:08:05,240
biex ngħidu hekk.

154
00:08:05,240 --> 00:08:07,430
U aħna ser tara dawn madwar
programmi C, kif ukoll

155
00:08:07,430 --> 00:08:08,930
JavaScript u PHP.

156
00:08:08,930 --> 00:08:11,345
U dawn biss jirrappreżentaw
linji relatati ta 'kodiċi.

157
00:08:11,345 --> 00:08:14,600
Il Brace kaboċċi open essenzjalment
jgħid, hawn taqa xi kodiċi.

158
00:08:14,600 --> 00:08:17,590
U l-Brace kaboċċi magħluq, li hija
angolata fid-direzzjoni oħra, biss

159
00:08:17,590 --> 00:08:19,920
mezzi, li hija għal
il-kodiċi rilevanti.

160
00:08:19,920 --> 00:08:22,970
>> Allura l-linja mmerraq f'din l-ewwel
programm huwa l-aħħar, printf,

161
00:08:22,970 --> 00:08:25,080
quote-unquote, bonjour dinja.

162
00:08:25,080 --> 00:08:30,670
U jien imsejjaħ il-ħaġa bejn
kwotazzjonijiet liema aħħar darba?

163
00:08:30,670 --> 00:08:31,285
Allura huwa string.

164
00:08:31,285 --> 00:08:35,309
U string huwa biss il-techie
tul għall sekwenza ta '

165
00:08:35,309 --> 00:08:37,169
karattri, kelma, frażi.

166
00:08:37,169 --> 00:08:39,380
Anke ittra waħda tista
jiġu kkwotati doppja.

167
00:08:39,380 --> 00:08:41,840
Imma hija sekwenza ta 'żero
jew aktar karattri.

168
00:08:41,840 --> 00:08:43,650
>> Backslash-n, għalkemm, jistenna
daqsxejn stramba.

169
00:08:43,650 --> 00:08:46,290
Iżda dan kien ifisser sempliċement xi ħaġa
sempliċi għall-kompjuter.

170
00:08:46,290 --> 00:08:48,060
X'hemm backslash-n?

171
00:08:48,060 --> 00:08:48,570
Linja ġdida.

172
00:08:48,570 --> 00:08:52,490
Allura dan huwa biss l-sekwenza speċjali ta '
karattri li d-dinja tkun iddeċidiet

173
00:08:52,490 --> 00:08:56,880
mezzi tpoġġi waqfa linja hemm dritt,
minħabba li l-kumpilatur fatt se tikseb

174
00:08:56,880 --> 00:09:02,280
konfuż, normalment, jekk inti, ħafna
jifhem, iżda b'mod żbaljat, biss

175
00:09:02,280 --> 00:09:04,570
jibdew laqtu Ikteb biex
linji ġodda fil-kodiċi tiegħek.

176
00:09:04,570 --> 00:09:07,150
Inti jeħtieġ li tkun ftit aktar
espliċitu bil backslash-n.

177
00:09:07,150 --> 00:09:10,540
>> U aħna ser tara hemm ieħor ftit
mudelli għall-karattri speċjali.

178
00:09:10,540 --> 00:09:14,340
Per eżempju, jekk inti riedu let tiegħek
mind wander għal każ kantuniera,

179
00:09:14,340 --> 00:09:18,080
jissoponi li xtaqt li jistampaw
kwotazzjoni doppja fuq l-iscreen

180
00:09:18,080 --> 00:09:21,840
kwalunkwe raġuni, li jidher li
jkun ftit problematika, right?

181
00:09:21,840 --> 00:09:24,990
Għaliex jekk nressaq kwotazzjoni doppja fil-
nofs ta '"hello, dinja," għal kwalunkwe

182
00:09:24,990 --> 00:09:30,120
raġuni, għaliex ma li jidhru
potenzjalment problematiċi?

183
00:09:30,120 --> 00:09:32,180
Pawżi-sekwenza.

184
00:09:32,180 --> 00:09:34,700
>> Il-kompilatur hija biss program.

185
00:09:34,700 --> 00:09:37,210
A program bħal kompilatur huwa biss se
biex taqra kodiċi tiegħek top għal isfel,

186
00:09:37,210 --> 00:09:37,990
xellug għal-lemin.

187
00:09:37,990 --> 00:09:41,850
U jekk jara tliet kwotazzjonijiet doppja minflok
ta 'tnejn, mhuwiex ser tkun taf

188
00:09:41,850 --> 00:09:45,210
jekk int tfisser li l-ħaġa fuq ix-xellug
għandu jkun il-string, jew il-ħaġa li

189
00:09:45,210 --> 00:09:46,570
id-dritt, jew il-ħaġa sħiħa.

190
00:09:46,570 --> 00:09:50,560
Huwa ambigwa, u iva, liema tipiku
kompilatur se tagħmel huwa biss skerz,

191
00:09:50,560 --> 00:09:53,710
u jagħtuk xi messaġġ ta 'żball, u
tagħmel inti jittrattaw mal-problema.

192
00:09:53,710 --> 00:09:58,120
>> Allura peress li backslash-n tfisser ġdida
linja, dak li instincts tiegħek issa

193
00:09:58,120 --> 00:10:02,610
jibdew ikunu jekk int riedu jinkludu
xi ħaġa anomala bħal double

194
00:10:02,610 --> 00:10:06,210
kwotazzjoni ġewwa ta 'dan altrimenti' ikkwotat
string?

195
00:10:06,210 --> 00:10:07,640
Kwotazzjoni backslash-double.

196
00:10:07,640 --> 00:10:09,630
U hekk aħna ser tara dan
tip ta 'mudell wisq.

197
00:10:09,630 --> 00:10:12,490
>> Jekk inti tixtieq li tagħmel xi ħaġa ftit
stramba, inti ser issib li l-

198
00:10:12,490 --> 00:10:15,060
soluzzjonijiet sikwit isegwu mudell,
u l-backslash

199
00:10:15,060 --> 00:10:17,150
tindika sekwenza ħarba.

200
00:10:17,150 --> 00:10:20,320
U dan ifisser biss xi ħaġa speċjali
li għandna bżonn li jirrappreżentaw b'mod

201
00:10:20,320 --> 00:10:21,060
b'mod differenti.

202
00:10:21,060 --> 00:10:23,830
Fir-rigward kif taħseb li jirrappreżentaw
backslash, ukoll, aħna ser

203
00:10:23,830 --> 00:10:24,550
terga 'lura għal dan.

204
00:10:24,550 --> 00:10:26,930
Iżda l-risposta, wisq, huwa attwalment
daqsxejn ovvji.

205
00:10:26,930 --> 00:10:31,080
>> Mela ejja issa jintroduċu xi oħra
constructs programmazzjoni

206
00:10:31,080 --> 00:10:31,915
li inti raw fil Scratch.

207
00:10:31,915 --> 00:10:34,790
You ħadthom probabbilment meħuda għall mogħtija
diġà jekk inti stajt diġà dived fis

208
00:10:34,790 --> 00:10:36,060
problema stabbiliti 0.

209
00:10:36,060 --> 00:10:40,950
Imma ejja issa jintroduċu s-sintassi fis-C
għal dawn inkella pjuttost intuwittivi

210
00:10:40,950 --> 00:10:42,300
ideat, għall-inqas xi wħud minnhom.

211
00:10:42,300 --> 00:10:45,570
>> Allura dan il-kunċett ta 'kundizzjoni jew
fergħa, filwaqt li qabel we

212
00:10:45,570 --> 00:10:49,330
irrappreżentata ma kodiċi li ħares
bħal dan fuq ix-xellug fil Scratch -

213
00:10:49,330 --> 00:10:52,200
jekk x huwa inqas minn y, allura jgħidu hekk -

214
00:10:52,200 --> 00:10:56,760
minflok issa C - let me hone
fuq il-każ sempliċi -

215
00:10:56,760 --> 00:11:01,235
aħna qed sempliċiment se ngħid, jekk, miftuħa
parentesi, xi ħaġa huwa veru - a

216
00:11:01,235 --> 00:11:04,190
Espressjoni Boolean se jmorru
fejn għidt kundizzjoni -

217
00:11:04,190 --> 00:11:08,170
parentesi qrib, allura x'hemm
ġewwa ta 'dawk ċingi kaboċċi.

218
00:11:08,170 --> 00:11:11,020
>> Allura hawnhekk, il-braces kaboċċi
huma tip ta 'prodotti simili tal Scratch

219
00:11:11,020 --> 00:11:12,460
Biċċiet puzzle U-forma.

220
00:11:12,460 --> 00:11:14,890
Do x'hemm ġewwa dawn braces kaboċċi.

221
00:11:14,890 --> 00:11:16,790
F'dan il-każ, mmejla mmejla.

222
00:11:16,790 --> 00:11:19,720
U l-avviż dan huwa l quddiem
mmejla, mhux backslash.

223
00:11:19,720 --> 00:11:21,440
Forward slash, quddiem mmejla,
għal dawk li ħadthom programmati

224
00:11:21,440 --> 00:11:23,370
qabel, ifisser biss -

225
00:11:23,370 --> 00:11:24,190
huwa biss kumment.

226
00:11:24,190 --> 00:11:26,630
A kumment mhix linja
tal-kodiċi, per se.

227
00:11:26,630 --> 00:11:30,200
Huwa linja tal-Ingliż li inti, l-
bniedem, kitbu lill lilek innifsek biex

228
00:11:30,200 --> 00:11:33,540
forsi infakkarkom li tagħmel xi ħaġa, għall-
jispjegaw lilek innifsek, tispjega lill-

229
00:11:33,540 --> 00:11:35,260
xi ħadd ieħor, dak kodiċi tiegħek qed tagħmel.

230
00:11:35,260 --> 00:11:37,050
Huwa biss kumment deskrittiv.

231
00:11:37,050 --> 00:11:40,880
>> Issa, naturalment, jista 'jkollna two-way
furketta fit-triq biss billi tagħmel dan,

232
00:11:40,880 --> 00:11:43,930
three-way furketta fit-triq billi tagħmel
dan, u jekk inti tkompli dan

233
00:11:43,930 --> 00:11:47,570
mudell, inti jista 'jkollhom erba' mod,
ħames postijiet, sitt mod frieket fit-triq jekk

234
00:11:47,570 --> 00:11:50,150
għandek bżonn biex jimmaniġġaw, tabilħaqq,
li ħafna kondizzjonijiet.

235
00:11:50,150 --> 00:11:52,010
U allura l-avviż paralleliżmu hawn -

236
00:11:52,010 --> 00:11:55,070
jekk (kundizzjoni), inkella jekk (kundizzjoni),
u l-unika waħda li ftit

237
00:11:55,070 --> 00:11:58,010
stramba hija l-aħħar, li
huwa biss li ħaddieħor.

238
00:11:58,010 --> 00:12:01,170
Iżda għal darb'oħra, dan huwa identiku,
kunċettwalment, għal dak li aħna ghamilt

239
00:12:01,170 --> 00:12:04,690
diġà, anki jekk il-sintassi se
tieħu ftit jkollna użati biex.

240
00:12:04,690 --> 00:12:07,730
>> Issa, f'dan l-eżempju, hemm
xi sintassi stramba ieħor.

241
00:12:07,730 --> 00:12:11,220
Naraw printf darb'oħra, parentesi miftuħa,
u parentesi qrib.

242
00:12:11,220 --> 00:12:13,190
U ġewwa tal hemm
string ikkwotat.

243
00:12:13,190 --> 00:12:17,060
Il-parentesi, fil-kuntest
ta 'printf, mur fuq ix-xellug

244
00:12:17,060 --> 00:12:18,160
u d-dritt ta 'xiex?

245
00:12:18,160 --> 00:12:22,190
What do we jiddeskrivu dak ikkwotat
string billi b'mod aktar ġenerali?

246
00:12:22,190 --> 00:12:23,320
>> Allura huwa argument.

247
00:12:23,320 --> 00:12:26,620
Kwalunkwe ħin li inti għandhom funzjoni, bħal
printf, u mbagħad paren miftuħa u

248
00:12:26,620 --> 00:12:30,330
paren qrib u xi ħaġa ġewwa tal
dan, jekk huwa string, jew

249
00:12:30,330 --> 00:12:34,420
numru sħiħ, jew xi ħaġa oħra, il-ħaġa fil-
bejn dawk parentesi hija msejħa

250
00:12:34,420 --> 00:12:35,110
argument.

251
00:12:35,110 --> 00:12:37,910
>> U l-argument biss tinfluwenza
imġieba tal-funzjoni tal-.

252
00:12:37,910 --> 00:12:39,990
F'dan il-każ, huwa pjuttost ċar kif.

253
00:12:39,990 --> 00:12:44,480
x <y huwa dak li jiġu mgħoddija fi,
biex ngħidu hekk, bħala argument.

254
00:12:44,480 --> 00:12:47,720
U printf se
print eżattament dan.

255
00:12:47,720 --> 00:12:51,590
Minħabba żgur, l-sena ta 'persuni ilu
li implimentat printf kellhom ebda idea

256
00:12:51,590 --> 00:12:55,000
dak li aħna suċċessuri tal-bniedem kienu
ser tuża printf għall.

257
00:12:55,000 --> 00:12:58,610
Allura hu għalhekk li jeżistu argumenti, li
jinfluwenzaw l-imġieba wara l-funzjoni

258
00:12:58,610 --> 00:12:59,450
ġie miktub.

259
00:12:59,450 --> 00:13:00,780
>> Issa, l-espressjoni Boolean.

260
00:13:00,780 --> 00:13:02,470
Rajna dawn qabel fil Scratch.

261
00:13:02,470 --> 00:13:06,680
Jirriżulta fil C tista 'wkoll "jew"
flimkien, biex ngħidu hekk.

262
00:13:06,680 --> 00:13:10,930
Żewġ bars vertikali ifisser li din il-blokka
tal-kodiċi, dan tagħmel dan, se

263
00:13:10,930 --> 00:13:15,350
tesegwixxi jekk l-ewwel kundizzjoni hija vera
jew it-tieni kundizzjoni huwa veru.

264
00:13:15,350 --> 00:13:17,710
U anki jekk inti ma tista għamlu
dan Scratch, inti tista tabilħaqq

265
00:13:17,710 --> 00:13:20,580
tagħmel dan Scratch, u tista 'wkoll
tesprimi ruħek b'mod differenti -

266
00:13:20,580 --> 00:13:25,300
jekk l-ewwel kundizzjoni u t-tieni
kondizzjoni huma veri, allura x'hemm

267
00:13:25,300 --> 00:13:27,160
ġewwa taċ-ċingi kaboċċi.

268
00:13:27,160 --> 00:13:31,210
>> U biss bħala twarrib, ir-raġuni huwa
a ampersand doppja u doppju

269
00:13:31,210 --> 00:13:34,610
bar vertikali, Ser naraw eventwalment
li bar vertikali waħda u

270
00:13:34,610 --> 00:13:38,710
ampersand waħda attwalment differenti
tifsira fil C. Allura għal issa,

271
00:13:38,710 --> 00:13:41,840
li d-duplikazzjoni ta 'simboli
huwa intenzjonat.

272
00:13:41,840 --> 00:13:45,070
>> Mela ejja jintroduċu, fil-qosor,
din id-daqsxejn ieħor ta 'sintassi.

273
00:13:45,070 --> 00:13:48,940
Dan ma pjuttost jiżdiedu ma
Scratch, imma jien jsostnu li nista '

274
00:13:48,940 --> 00:13:55,190
timplimenta l-kunċett ta 'jekk inkella, jekk
inkella, jekk inkella, jekk id-dikjarazzjoni inkella jużaw

275
00:13:55,190 --> 00:13:56,760
xi ħaġa imsejħa 'dikjarazzjoni swiċċ.

276
00:13:56,760 --> 00:14:00,820
U l-unika raġuni dan verament teżisti
hija li biss jagħtuk, il-programmer, a

277
00:14:00,820 --> 00:14:05,470
b'mod kemmxejn differenti ta 'soluzzjoni xi
problema, għalkemm loġikament

278
00:14:05,470 --> 00:14:07,340
ma jagħtuk l-ebda kapaċitajiet ġodda.

279
00:14:07,340 --> 00:14:08,530
>> Permezz I tfisser dan.

280
00:14:08,530 --> 00:14:13,330
Meta inti tgħidli swiċċ, u mbagħad spazju,
u mbagħad par parentesi, ġewwa

281
00:14:13,330 --> 00:14:14,570
tiegħu tmur espressjoni -

282
00:14:14,570 --> 00:14:18,010
u dan jista 'jkun mhux ovvju ftit
fl-ewwel, iżda dan mhuwiex argument,

283
00:14:18,010 --> 00:14:20,680
teknikament, minħabba swiċċ
mhix funzjoni.

284
00:14:20,680 --> 00:14:24,230
Allura għal issa, biss wieħed jassumi li aħna qed tuża
parentesi f'postijiet differenti

285
00:14:24,230 --> 00:14:25,250
għal raġunijiet differenti.

286
00:14:25,250 --> 00:14:29,310
>> Allura swiċċ dwar l-espressjoni ifisser I jistgħu
tpoġġi ġewwa varjabbli ta 'dawk

287
00:14:29,310 --> 00:14:31,350
parentesi fejn jgħid espressjoni.

288
00:14:31,350 --> 00:14:33,090
U mbagħad jekk dak il-varjabbli -

289
00:14:33,090 --> 00:14:35,400
jissoponi huwa msejjaħ x, u
huwa biss numru sħiħ -

290
00:14:35,400 --> 00:14:38,900
I jistgħu mbagħad telenka slide tiegħi
hawn xi ħaġa bħal din.

291
00:14:38,900 --> 00:14:41,690
Jekk x hija varjabbli tiegħi, u jien
trid tagħmel xi ħaġa jekk x

292
00:14:41,690 --> 00:14:43,480
daqs 1, I tista 'tagħmel dan.

293
00:14:43,480 --> 00:14:46,660
>> Jekk I minflok trid tagħmel xi ħaġa
jekk x huwa 2, I tista 'tagħmel dan.

294
00:14:46,660 --> 00:14:50,390
Else, jekk irrid li tagħmel xi ħaġa oħra
kollox, I jista 'jkollhom każ normali fl

295
00:14:50,390 --> 00:14:52,750
f'liema każ I do dan ħaġa oħra.

296
00:14:52,750 --> 00:14:58,730
Allura f'dan is-sens, huwa ekwivalenti għal
jekk x ugwali daqs 1, inkella jekk inkella,

297
00:14:58,730 --> 00:15:01,150
imma nsemmi dan issa biss minħabba
aħna ser tara mill-ġdid.

298
00:15:01,150 --> 00:15:03,720
Iżda għal issa, biss jafu li jeżisti.

299
00:15:03,720 --> 00:15:04,220
>> Kull dritt.

300
00:15:04,220 --> 00:15:07,660
Allura dawn l-aħħar ftit huma ftit aktar
kumpless ewwel daqqa t'għajn, iżda dawn ma

301
00:15:07,660 --> 00:15:09,385
xi ħaġa pjuttost sempliċi.

302
00:15:09,385 --> 00:15:14,410
A għall-loop fil Ċ hija blokki ta 'kodiċi li
biss ma xi ħaġa mill-ġdid u

303
00:15:14,410 --> 00:15:15,330
ġdid u għal darb'oħra.

304
00:15:15,330 --> 00:15:17,590
U l-unika ħaġa dwar dan huwa annoying
li huwa li huwa ftit cryptic

305
00:15:17,590 --> 00:15:21,380
biex tesprimi ruħek f'din ċikliku
mudell, iżda fid-dinja standardizzat fuq

306
00:15:21,380 --> 00:15:22,450
il-mod li ġej.

307
00:15:22,450 --> 00:15:25,760
>> Meta tuża għal loop, inti stajt ltqajna
par parentesi mill-ġdid.

308
00:15:25,760 --> 00:15:27,570
U avviż-żewġ semicolons
fil hemmhekk.

309
00:15:27,570 --> 00:15:34,380
Dawk iż-żewġ semicolons separati tliet
espressjonijiet differenti ġewwa ta 'l-

310
00:15:34,380 --> 00:15:35,020
parentesi.

311
00:15:35,020 --> 00:15:37,170
Wieħed huwa l-hekk imsejħa initializations.

312
00:15:37,170 --> 00:15:38,830
Wieħed huwa l-kondizzjoni hekk imsejħa.

313
00:15:38,830 --> 00:15:40,210
U waħda hija l-hekk imsejħa aġġornamenti.

314
00:15:40,210 --> 00:15:43,240
>> Ħares lejn in abstracto, dan huwa
kompletament mhux ovvju, hekk ejja nħarsu

315
00:15:43,240 --> 00:15:44,630
lejn eżempju konkret.

316
00:15:44,630 --> 00:15:46,720
Fl Scratch kellna blokk ripetuti.

317
00:15:46,720 --> 00:15:50,670
U dan il-blokk qal irrepeti 10 darbiet, jgħidu
"Hello, dinja." Let me talba għal

318
00:15:50,670 --> 00:15:53,810
issa, u aħna ser terga 'lura għal dan, u
dan, wisq, se tikseb aktar familjari

319
00:15:53,810 --> 00:15:57,345
inti qabel twil, il-C ekwivalenti
kodiċi jista 'jingħad li dan -

320
00:15:57,345 --> 00:16:02,320
a għal dikjarazzjoni u spazju, par ta '
parentesi, avviż l-semicolons fil

321
00:16:02,320 --> 00:16:05,730
hemm, li jifirdu tliet distinta
affarijiet, l-inizjalizzazzjoni, il-

322
00:16:05,730 --> 00:16:07,320
kondizzjoni, u l-aġġornament.

323
00:16:07,320 --> 00:16:08,840
>> U tieħu raden liema
l-ewwel qed tagħmel.

324
00:16:08,840 --> 00:16:10,690
I int = 0.

325
00:16:10,690 --> 00:16:15,120
F'termini layman rough, l x'inhu
li tagħmel għalina, probabbilment?

326
00:16:15,120 --> 00:16:15,590
So yeah.

327
00:16:15,590 --> 00:16:19,630
Huwa tiddikjara varjabbli imsejjaħ i,
u huwa jtuha liema valur?

328
00:16:19,630 --> 00:16:20,220
0.

329
00:16:20,220 --> 00:16:24,280
Allura huwa ħolqien ta 'varjabbli msejħa
i, il-ħażna l-valur 0 fiha.

330
00:16:24,280 --> 00:16:26,420
Dik hija l-inizjalizzazzjoni hekk imsejħa.

331
00:16:26,420 --> 00:16:29,360
>> Kull dritt, issa I iddikjara quddiem
li l-ħaġa nofs, i

332
00:16:29,360 --> 00:16:31,760
<10, hija l-kundizzjoni.

333
00:16:31,760 --> 00:16:32,730
Allura dak li qed tagħmel?

334
00:16:32,730 --> 00:16:36,560
Ukoll, dak li l-linja għal ma meta
programm bil għal loop hija mmexxija, huwa

335
00:16:36,560 --> 00:16:41,050
kull darba li l-kompjuter runs permezz
dan loop, fuq għal isfel, fuq għal

336
00:16:41,050 --> 00:16:43,740
qiegħ, bħad inti guys għamlet meta
għadd infuskom u bilqiegħda,

337
00:16:43,740 --> 00:16:47,090
ġdid u għal darb'oħra u għal darb'oħra,
il-kompjuter huwa għaddej

338
00:16:47,090 --> 00:16:48,560
biex jiċċekkjaw din il-kundizzjoni.

339
00:16:48,560 --> 00:16:51,140
U jekk i huwa inqas minn 10,
dan ser jagħmlu mill-ġdid.

340
00:16:51,140 --> 00:16:53,100
Jekk i huwa inqas minn 10,
dan ser jagħmlu mill-ġdid.

341
00:16:53,100 --> 00:16:55,030
Jekk i huwa anqas minn għaxra,
dan ser jagħmlu mill-ġdid.

342
00:16:55,030 --> 00:16:57,330
Allura li jidher li tissuġġerixxi li
nisperaw i qed tinbidel.

343
00:16:57,330 --> 00:16:59,010
Inkella, aħna'd jkollhom loop infinita.

344
00:16:59,010 --> 00:17:02,590
U fil-fatt, i qed tinbidel, minħabba li l-
aħħar ħaġa wara l-virgola hemm

345
00:17:02,590 --> 00:17:05,569
huwa l-sintassi kemmxejn cryptic ta 'i + +.

346
00:17:05,569 --> 00:17:07,630
Iżda dawk tal inti li ghamilt dan
qabel, li ifisser biss

347
00:17:07,630 --> 00:17:08,609
sempliċement liema?

348
00:17:08,609 --> 00:17:09,730
>> STUDENTI: [INTERPOSING VUĊI].

349
00:17:09,730 --> 00:17:10,740
>> DAVID Malan: Żid 1 sa i.

350
00:17:10,740 --> 00:17:11,819
Inkrement i.

351
00:17:11,819 --> 00:17:13,910
Allura rajna puzzle Scratch
biċċa għal dan, fil-fatt.

352
00:17:13,910 --> 00:17:18,230
Hija ma look like i + +, iżda biss li
ifisser, pjuttost sempliċi, l-inkrement

353
00:17:18,230 --> 00:17:24,040
valur i b'1 kull darba li inti tagħmel dan.

354
00:17:24,040 --> 00:17:26,910
Allura litteralment, inti tibda billi
initializing i għal 0.

355
00:17:26,910 --> 00:17:29,520
Inti mbagħad tiċċekkja l-kundizzjoni tiegħek.

356
00:17:29,520 --> 00:17:31,070
Huwa 0 inqas minn 10?

357
00:17:31,070 --> 00:17:31,730
Iva.

358
00:17:31,730 --> 00:17:32,910
Immorru permezz tal-linja.

359
00:17:32,910 --> 00:17:35,150
>> Il-ħaġa li jmiss I pretensjoni tal-kompjuter tal-
se tagħmel huwa li għaddej

360
00:17:35,150 --> 00:17:35,910
għall inkrement i.

361
00:17:35,910 --> 00:17:37,080
Hekk i issa huwa 1.

362
00:17:37,080 --> 00:17:37,940
Tikkontrolla l-kundizzjoni.

363
00:17:37,940 --> 00:17:39,290
Huwa 1 inqas minn 10?

364
00:17:39,290 --> 00:17:39,930
Of course.

365
00:17:39,930 --> 00:17:41,030
Allura ma mill-ġdid.

366
00:17:41,030 --> 00:17:43,580
Imbagħad inkrementi i + + għal 2.

367
00:17:43,580 --> 00:17:44,610
Huwa inqas minn 2 10?

368
00:17:44,610 --> 00:17:45,230
Iva.

369
00:17:45,230 --> 00:17:46,670
U għal darb'oħra u għal darb'oħra u għal darb'oħra.

370
00:17:46,670 --> 00:17:50,070
U eventwalment, minħabba l-
plus-plussing, we biex i ugwali għal 10.

371
00:17:50,070 --> 00:17:51,675
Huwa 10 inqas minn 10?

372
00:17:51,675 --> 00:17:52,990
Well, ovvjament le.

373
00:17:52,990 --> 00:17:55,320
U dak l-punt li fih
l għal loop biss waqfiet.

374
00:17:55,320 --> 00:17:58,320
U jekk għandek aktar kodiċi fuq il-
screen stabbiliti hawn taħt, il-kompjuter

375
00:17:58,320 --> 00:18:01,620
rikavat biex imexxu dan il-kodiċi minflok.

376
00:18:01,620 --> 00:18:05,380
>> Għalhekk għal darb'oħra, anke jekk dan se
dehra u sensazzjoni ftit stramba fil

377
00:18:05,380 --> 00:18:07,830
ewwel, ċertament għal dawk minnkom li
qatt programmati qabel, huwa

378
00:18:07,830 --> 00:18:11,640
litteralment inaqqas kunċettwalment
biex x'hemm inkella ħafna

379
00:18:11,640 --> 00:18:14,330
puzzle sempliċi
biċċa fl Scratch.

380
00:18:14,330 --> 00:18:19,130
>> Kull dritt, I wiegħed li hemm theyd
jkun analogs oħra Scratch.

381
00:18:19,130 --> 00:18:20,060
Hemm dan wieħed wisq.

382
00:18:20,060 --> 00:18:21,700
U aħna raw dan fil-qosor aħħar darba.

383
00:18:21,700 --> 00:18:23,530
Iżda tiftakar l-dejjem
blokk fil Scratch?

384
00:18:23,530 --> 00:18:25,490
Hija biss ma xi ħaġa għal dejjem?

385
00:18:25,490 --> 00:18:27,470
I qal li inti tista 'timplimenta
din b'dan il-mod.

386
00:18:27,470 --> 00:18:29,740
U inti tista 'attwalment timplimenta dan
fil-mazz ta 'modi differenti.

387
00:18:29,740 --> 00:18:34,260
>> Iżda l-linja filwaqt li huwa biss differenti
mod C ta 'tesprimi lilek innifsek.

388
00:18:34,260 --> 00:18:37,080
Fl-aħħar tal-ġurnata, inti ma tistax tagħmel
xejn ma filwaqt li loop li inti

389
00:18:37,080 --> 00:18:38,360
ma jistgħux ma 'għall-loop.

390
00:18:38,360 --> 00:18:41,430
Allura dawn qed fl-aħħar ta 'l-
jum funzjonalment l-istess.

391
00:18:41,430 --> 00:18:43,840
Iżda tippermetti li inti biex tesprimi ruħek
ftit differenti fil-

392
00:18:43,840 --> 00:18:44,850
il-mod li ġej.

393
00:18:44,850 --> 00:18:49,720
>> Bl-linja waqt, huwa x'hemm fil
parentesi thats ċċekkjati għal darb'oħra u

394
00:18:49,720 --> 00:18:51,050
ġdid u għal darb'oħra.

395
00:18:51,050 --> 00:18:55,100
U hekk kif dik l-espressjoni hija falza,
allura l-linja waqfiet eżekuzzjoni,

396
00:18:55,100 --> 00:18:57,890
u l-kompjuter tipproċedi biex
run kwalunkwe kodiċi ieħor inti

397
00:18:57,890 --> 00:18:59,230
jkollhom fil-fajl tiegħek.

398
00:18:59,230 --> 00:19:02,180
>> Imma x'hemm interessanti hawnhekk huwa
li I litteralment ittajpjat veru.

399
00:19:02,180 --> 00:19:06,680
U vera huwa tip ta 'valur Boolean,
valur veru jew falza.

400
00:19:06,680 --> 00:19:09,750
Allura jista vera qatt sar
falza jekk stajt litteralment

401
00:19:09,750 --> 00:19:11,970
hard-kodifikati fis program tiegħi?

402
00:19:11,970 --> 00:19:12,470
Allura l-ebda.

403
00:19:12,470 --> 00:19:13,730
Huwa ftit stramba li għamilt dan.

404
00:19:13,730 --> 00:19:15,190
Imma veru huwa veru.

405
00:19:15,190 --> 00:19:16,320
M'hemm l-ebda plus-plussing.

406
00:19:16,320 --> 00:19:17,820
M'hemm l-ebda użu ta 'varjabbli fil hawn.

407
00:19:17,820 --> 00:19:22,740
So I għaliex hard-kodifikati filwaqt vera, dan
loop huwa dejjem se tevalwa

408
00:19:22,740 --> 00:19:24,090
ġdid u għal darb'oħra u għal darb'oħra.

409
00:19:24,090 --> 00:19:27,660
>> Allura kif ħafna drabi hija dinja bonjour
morna għall-istampa fuq l-iskrin?

410
00:19:27,660 --> 00:19:28,170
Forever.

411
00:19:28,170 --> 00:19:31,980
Numru infinit ta 'drabi sakemm il-
imut batterija jew xi esterni oħra

412
00:19:31,980 --> 00:19:32,730
avveniment jiġri.

413
00:19:32,730 --> 00:19:35,880
Allura dan huwa probabbilment mhux l-aħjar programm
li tikteb, għaliex jekk l-utent

414
00:19:35,880 --> 00:19:38,660
qatt ma tista nieqaf program tiegħek, huwa
probabbilment mhux dak li int maħsuba.

415
00:19:38,660 --> 00:19:41,070
>> Imma kultant, il-programmi għandhom
jkollhom loop infinita.

416
00:19:41,070 --> 00:19:44,050
Per eżempju, jekk il-kompjuter tiegħek għandha
arloġġ fuqha, li ċertament ikun

417
00:19:44,050 --> 00:19:48,130
sbieħ jekk arloġġ tiegħek ma żżomm aġġornament
innifsu dejjem, għalkemm ladarba

418
00:19:48,130 --> 00:19:50,500
tieni jew darba minuta jew
xi ħaġa bħal dik.

419
00:19:50,500 --> 00:19:53,690
Loops hekk anke infinita
do jkollhom post tagħhom.

420
00:19:53,690 --> 00:19:54,360
>> Kull dritt.

421
00:19:54,360 --> 00:19:55,190
Fl-aħħar nett, dan wieħed.

422
00:19:55,190 --> 00:19:57,770
U dan huwa wieħed ftit differenti
funzjonalment, u aħna ser terga 'lura għal

423
00:19:57,770 --> 00:19:59,460
dan probabbilment fil Pset 1.

424
00:19:59,460 --> 00:20:02,370
Iżda hemm tip ieħor ta 'loop
imsejħa tagħmel waqt loop.

425
00:20:02,370 --> 00:20:07,100
U l-unika differenza hawnhekk bejn
tagħmel filwaqt loop u, jgħidu, filwaqt li loop,

426
00:20:07,100 --> 00:20:11,120
huwa li l-kondizzjoni hija vverifikata ma
qabel inti teżegwixxi l-kodiċi, iżda wara

427
00:20:11,120 --> 00:20:12,080
inti teżegwixxi l-kodiċi.

428
00:20:12,080 --> 00:20:15,380
Allura fil-quċċata għall-waqt
loop, billi l-tagħmel waqt

429
00:20:15,380 --> 00:20:16,560
kontrolli li fil-qiegħ.

430
00:20:16,560 --> 00:20:21,370
>> U dan ifisser biss li l-linja filwaqt li
tipikament se tesegwixxi darbiet aktar

431
00:20:21,370 --> 00:20:24,630
jew fi żminijiet inqas minn filwaqt li loop?

432
00:20:24,630 --> 00:20:30,810
Potenzjalment darbiet aktar, għaliex do
filwaqt li loop huwa qal b'mod ċar tagħmel dan,

433
00:20:30,810 --> 00:20:34,600
biss wara li punt inti tiċċekkja
jekk il-ġewwa kondizzjoni tal-

434
00:20:34,600 --> 00:20:35,980
parentesi huwa veru.

435
00:20:35,980 --> 00:20:37,940
>> Allura aħna ser tara dan mill-ġdid
probabbilment Pset 1.

436
00:20:37,940 --> 00:20:41,150
Jekk inti qatt trid tagħmel xi ħaġa fil
inqas darba u mbagħad forsi ftit aktar

437
00:20:41,150 --> 00:20:43,350
drabi, dan huwa tajjeb
jibnu għall-użu.

438
00:20:43,350 --> 00:20:46,970
Iżda filwaqt li loop, b'kuntrast, se
jiċċekkja l-kondizzjoni tiegħu ewwel.

439
00:20:46,970 --> 00:20:50,660
U li huwa għal loops fis-C, ma
filwaqt li, filwaqt li, u għal loops.

440
00:20:50,660 --> 00:20:54,700
U għal darb'oħra, huma mappa pretty nicely lura
li tobrox, ħlief dan wieħed ma

441
00:20:54,700 --> 00:20:57,350
pjuttost jkollhom l-istess Analog Scratch.

442
00:20:57,350 --> 00:20:58,880
>> Ukoll, kif madwar, issa, varjabbli?

443
00:20:58,880 --> 00:21:02,600
Allura dan huwa kif I iddikjarat varjabbli
sintattikament l-oħra jum.

444
00:21:02,600 --> 00:21:06,440
I kellhom int, li jiena mitlub
huwa integer.

445
00:21:06,440 --> 00:21:09,690
I imbagħad kellhom imsejjaħ counter varjabbli,
u mbagħad punto virgola.

446
00:21:09,690 --> 00:21:11,070
Allura x'inhi din il-linja tal-kodiċi tagħmel?

447
00:21:11,070 --> 00:21:14,540
Dan huwa, pjuttost sempliċi, li tiddikjara
varjabbli -

448
00:21:14,540 --> 00:21:17,940
jiġifieri, titlob lill-kompjuter, agħti lili
xi memorja, tagħti me xi bits - fil

449
00:21:17,940 --> 00:21:19,450
li I jista 'jaħżen dak?

450
00:21:19,450 --> 00:21:20,300
An int.

451
00:21:20,300 --> 00:21:23,570
U l-virgola ifisser biss
aħħar tal-linja tal-kodiċi.

452
00:21:23,570 --> 00:21:25,500
>> Issa, it-tieni linja hija probabbilment
pretty guessable.

453
00:21:25,500 --> 00:21:29,710
X'inhu counter = 0; tagħmel?

454
00:21:29,710 --> 00:21:31,690
Huwa jassenja 0 biex jiġġieldu.

455
00:21:31,690 --> 00:21:33,470
U għalhekk dan huwa l-ħaġa oħra
thats ftit annoying

456
00:21:33,470 --> 00:21:34,540
versus, ngħidu aħna, alġebra.

457
00:21:34,540 --> 00:21:39,110
Billi fl-alġebra, is-sinjal ugwali jfisser
ugwali, hawn fis-C, l-ugwaljanza

458
00:21:39,110 --> 00:21:40,470
sinjal jagħti assenjazzjoni.

459
00:21:40,470 --> 00:21:45,380
Allura dan ifisser tpoġġi x'hemm fuq il-lemin
fis x'hemm fuq ix-xellug.

460
00:21:45,380 --> 00:21:49,030
U aħna ser tara simbolu ieħor, ugwali
ugwali, meta rridu attwalment jittestjaw

461
00:21:49,030 --> 00:21:50,570
għall-kwalità, kemmxejn annoyingly.

462
00:21:50,570 --> 00:21:52,590
>> Iżda din hija ftit ineffiċjenti.

463
00:21:52,590 --> 00:21:55,090
Huwa tip ta 'annoying li għandi
li tiddikjara varjabbli u

464
00:21:55,090 --> 00:21:56,110
allura tagħtiha valur.

465
00:21:56,110 --> 00:21:59,380
Allura C attwalment tikri us jissimplifika dan
u biss tagħmel dan kollu f'daqqa.

466
00:21:59,380 --> 00:22:01,330
Tista 'tiddikjara l-varjabbli
fuq ix-xellug.

467
00:22:01,330 --> 00:22:04,590
Inti xorta tista 'tagħmel l-assenjazzjoni fuq l-
dritt billi dan is-sinjal ugwali fl-

468
00:22:04,590 --> 00:22:05,030
-nofs.

469
00:22:05,030 --> 00:22:08,740
Għalhekk fl-aħħar tal-ġurnata, dawn tnejn huma
ekwivalenti, iżda dan wieħed, franchement,

470
00:22:08,740 --> 00:22:11,840
huwa probabbilment l-aħjar vizzju li jsibu rwieħhom
biss għaliex dan huwa ftit inqas

471
00:22:11,840 --> 00:22:15,040
kodiċi, huwa ftit aktar faċli biex jinqraw,
u hija biss tagħmel aktar stretti r

472
00:22:15,040 --> 00:22:17,470
kodiċi tiegħek, biex ngħidu hekk.

473
00:22:17,470 --> 00:22:22,120
>> Kwalunkwe mistoqsijiet s'issa fuq il-linji,
fuq varjabbli, fuq il-kundizzjonijiet, fuq

474
00:22:22,120 --> 00:22:27,001
Booleans, jew teknikament
jew kunċettwalment?

475
00:22:27,001 --> 00:22:28,010
Kull dritt.

476
00:22:28,010 --> 00:22:30,690
Allura issa dan wieħed li jmiss gets a
ftit aktar interessanti.

477
00:22:30,690 --> 00:22:34,790
U dan huwa l-eżempju I impoġġija aħħar
ħin li biss mapep eżempju Scratch

478
00:22:34,790 --> 00:22:35,820
quddiem għall C.

479
00:22:35,820 --> 00:22:36,580
>> Allura funzjoni.

480
00:22:36,580 --> 00:22:38,110
F'termini layman, x'hemm funzjoni?

481
00:22:38,110 --> 00:22:42,900

482
00:22:42,900 --> 00:22:44,350
Ltqajna biex tkun aktar deċiża bi tweġiba tiegħek.

483
00:22:44,350 --> 00:22:45,020
X'hemm funzjoni?

484
00:22:45,020 --> 00:22:46,320
>> STUDENT: Does xi ħaġa.

485
00:22:46,320 --> 00:22:46,780
>> DAVID Malan: X'hemm li?

486
00:22:46,780 --> 00:22:48,000
>> STUDENT: Does xi ħaġa.

487
00:22:48,000 --> 00:22:48,710
>> DAVID Malan: Does xi ħaġa.

488
00:22:48,710 --> 00:22:49,000
OK.

489
00:22:49,000 --> 00:22:49,590
Aħna ser tibda hemmhekk.

490
00:22:49,590 --> 00:22:51,270
Allura funzjoni ma xi ħaġa.

491
00:22:51,270 --> 00:22:55,160
Allura huwa biċċa ta 'kodiċi li l-
implimentata essenzjalment x'imkien ieħor li

492
00:22:55,160 --> 00:22:56,620
tabilħaqq ma xi ħaġa.

493
00:22:56,620 --> 00:23:00,180
Issa, x'hemm interessanti dwar funzjoni
huwa li jista 'jieħu input,

494
00:23:00,180 --> 00:23:02,710
u jista 'jipproduċi output.

495
00:23:02,710 --> 00:23:05,090
U ejja fil-fatt tieħu
ħarsa lejn din.

496
00:23:05,090 --> 00:23:09,030
>> Allura l-bniedem wara l-purtiera
kien intenzjonat mument ilu.

497
00:23:09,030 --> 00:23:10,320
Hawnhekk għandna tabella.

498
00:23:10,320 --> 00:23:13,010
Iżda jissoponi li dan fil-fatt
jirrappreżenta kaxxa kbira.

499
00:23:13,010 --> 00:23:14,940
Allura dan huwa kaxxa sewda hekk imsejħa.

500
00:23:14,940 --> 00:23:19,800
U b'mod ġenerali, fid-disinn, fil-kompjuter
xjenza, kaxxi s-suwed biss jirreferu għal

501
00:23:19,800 --> 00:23:22,510
biċċiet ta 'funzjonalità li xi ħadd
implimentat, u inti ma

502
00:23:22,510 --> 00:23:26,140
neċessarjament jaf jew kura kif huwa
implimentati taħt il-barnuża.

503
00:23:26,140 --> 00:23:28,960
Inti biss kura li din il-kaxxa sewda,
li aħna issa ser tibda ssejjaħ

504
00:23:28,960 --> 00:23:30,730
, il-funzjoni ma xi ħaġa.

505
00:23:30,730 --> 00:23:34,710
>> Għalhekk, per eżempju, jekk din il-kaxxa sewda fuq
l-istadju hawn jirrappreżenta printf, a

506
00:23:34,710 --> 00:23:38,040
funzjoni, naf mill-eżempji ta 'qabel
li printf tieħu waħda jew aktar

507
00:23:38,040 --> 00:23:40,910
argumenti, u l-ewwel ta 'dawk
argumenti għandu jkun string, bħal

508
00:23:40,910 --> 00:23:44,780
"Hello, dinja." Ukoll, jekk I am il-persuna
miktub tal-programm, u nixtieq

509
00:23:44,780 --> 00:23:50,460
għall-użu printf, I, per eżempju, tista '
tieħu biċċa karta vojta hawn u

510
00:23:50,460 --> 00:23:55,060
markatur iswed u jiktbu fuqha -

511
00:23:55,060 --> 00:23:56,580
I misspelled "dinja" -

512
00:23:56,580 --> 00:23:59,560
H-E-L-L-O.

513
00:23:59,560 --> 00:24:04,220
>> So I ser tieħu markatur iswed tiegħi u jien ser
jiktbu, bħala kbar u li jinqara kif I tista 'fuq

514
00:24:04,220 --> 00:24:07,260
din il-biċċa ta 'karta, "hello, dinja," U
issa I titlob dan huwa argument tiegħi.

515
00:24:07,260 --> 00:24:09,740
Din hija string rappreżentati ma
biċċa karta bajda.

516
00:24:09,740 --> 00:24:13,030
U input tiegħi issa għall-funzjoni
printf se tkun din.

517
00:24:13,030 --> 00:24:18,250
So I am ssejjaħ printf, li jgħaddi
dan l-argument bħala input lilha.

518
00:24:18,250 --> 00:24:22,110

519
00:24:22,110 --> 00:24:26,740
>> U issa, jien ma nafx kif il-persuna li
kiteb printf ma kien snin ilu, iżda

520
00:24:26,740 --> 00:24:31,110
I do know minn dokumentazzjoni tiegħu li
l-għan tagħha fil-ħajja huwa li jistampaw dak I

521
00:24:31,110 --> 00:24:34,410
jipprovdu għaliha bħala input.

522
00:24:34,410 --> 00:24:40,630
U hekk, anki jekk din l-implimentazzjoni
huwa unbeknownst lili

523
00:24:40,630 --> 00:24:44,170
taħt il-barnuża, issa
Nara, oh, dan isir.

524
00:24:44,170 --> 00:24:45,740
Hija stampata xi ħaġa
fuq l-iskrin.

525
00:24:45,740 --> 00:24:49,070
U issa kontroll tal-programm, jekk ikun hemm
kienu aktar linji ta 'kodiċi, se

526
00:24:49,070 --> 00:24:51,070
issa rritornaw lili.

527
00:24:51,070 --> 00:24:52,290
U għalhekk il-fatt li Colton -

528
00:24:52,290 --> 00:24:55,370
bless qalb tiegħu, huwa ħabi hawn taħt
tabella fl-quddiem ta 'lilkom kollha -

529
00:24:55,370 --> 00:24:59,530
huwa intenzjonat f'dak jien ma nafx
u jien ma 'kura kif huwa printf

530
00:24:59,530 --> 00:25:00,100
implimentati.

531
00:25:00,100 --> 00:25:03,390
I biss jafu, għal darb'oħra, mill tagħha
dokumentazzjoni, x'tagħmel u kif I

532
00:25:03,390 --> 00:25:05,040
am suppost li jużawh.

533
00:25:05,040 --> 00:25:09,140
>> Issa, ifakkar li printf jistgħu jiksbu
ftit aktar sofistikati.

534
00:25:09,140 --> 00:25:12,220
Għal darb'oħra, aħna qed biss jitkellem dwar il-
ekwivalenti ta 'blokk Say Scratch tal.

535
00:25:12,220 --> 00:25:14,230
I iżda wkoll ma 'dan l-aħħar darba.

536
00:25:14,230 --> 00:25:17,270
I riedu jagħmlu programm bonjour tiegħi
ftit aktar dinamiku u mhux biss hard

537
00:25:17,270 --> 00:25:19,740
kodiċi xi ħaġa bħal "dinja," u
żgur li mhux xi ħaġa iebsa kodiċi

538
00:25:19,740 --> 00:25:22,520
arbitrarja bħal D-A-V-I-D
fil-programm.

539
00:25:22,520 --> 00:25:27,510
Jien ridt li jistaqsu l-utent għall tiegħu jew tagħha
isem, u mbagħad tagħmel xi ħaġa ma

540
00:25:27,510 --> 00:25:29,720
li string li huma jipprovdu.

541
00:25:29,720 --> 00:25:32,690
>> Allura hemm xi ftit differenti
hawn. printf, mument ilu,

542
00:25:32,690 --> 00:25:35,860
ma, tabilħaqq, jagħmel xi ħaġa, iżda
ma reġgħux lura xejn lili.

543
00:25:35,860 --> 00:25:36,020
Dritt?

544
00:25:36,020 --> 00:25:38,910
Colton ma idejn me xejn
lura, l-ebda biċċa karta.

545
00:25:38,910 --> 00:25:40,320
Kien hemm biss effett sekondarju.

546
00:25:40,320 --> 00:25:44,510
My jipprovdu "hello, dinja" bħala
argument li Colton irriżulta fil-

547
00:25:44,510 --> 00:25:48,420
effett sekondarju ta 'kelma, xi kliem,
jidhru fuq l-iskrin.

548
00:25:48,420 --> 00:25:51,350
>> getstring, għalkemm, huwa ftit
differenti. getstring huwa wkoll

549
00:25:51,350 --> 00:25:54,590
jiffunzjonaw, imma dan jirritorna xi valur.

550
00:25:54,590 --> 00:25:56,370
Ma biss ikollhom
effett sekondarju estetika.

551
00:25:56,370 --> 00:26:00,230
Hija fil-fatt tagħti me, il-persuna
sejħa jew tuża l-funzjoni,

552
00:26:00,230 --> 00:26:01,320
xi ħaġa lura.

553
00:26:01,320 --> 00:26:05,740
Allura f'dan il-każ, huwa getstring
imsejħa mal getstring miftuħ

554
00:26:05,740 --> 00:26:07,510
paren, paren qrib.

555
00:26:07,510 --> 00:26:11,370
Ma getstring, għalhekk, jieħdu
ebda argument jew input?

556
00:26:11,370 --> 00:26:12,340
Le, jidher le.

557
00:26:12,340 --> 00:26:14,460
L-għan tiegħu fil-ħajja huwa
biss li tikseb string.

558
00:26:14,460 --> 00:26:16,910
Jeħtieġ aktar dettall minn dak.

559
00:26:16,910 --> 00:26:20,430
So let me go quddiem u nippretendu li,
għal darb'oħra, din il-kaxxa sewda mhix printf,

560
00:26:20,430 --> 00:26:25,160
iżda getstring, u let me, il-persuna
miktub dan il-programm, is-sejħa jew l-użu

561
00:26:25,160 --> 00:26:29,720
getstring bi ftit miktub
G-E-T-S-T-R-I-N-G, open paren, qrib

562
00:26:29,720 --> 00:26:32,170
paren, getstring.

563
00:26:32,170 --> 00:26:36,920
>> Issa, għandi l-ebda idea kif il-persunal CS50
implimentati getstring, imma naf li

564
00:26:36,920 --> 00:26:41,240
jekk I stenna twil biżżejjed, hija se tagħmel tagħha
Ħaġa taħt il-barnuża, forsi bl-użu

565
00:26:41,240 --> 00:26:44,940
xi varjabbli, forsi jużaw xi
kundizzjonijiet, forsi tuża xi loops,

566
00:26:44,940 --> 00:26:48,170
forsi jużaw xi funzjonijiet,
forsi bl-użu -

567
00:26:48,170 --> 00:26:52,290
biss jippruvaw stall - forsi jużaw
xi karatteristiċi oħra ta 'programmazzjoni.

568
00:26:52,290 --> 00:26:55,350
Imma jekk I stenna twil biżżejjed - fir-realtà,
fil-kompjuter, dan jiġri

569
00:26:55,350 --> 00:26:56,270
super fast -

570
00:26:56,270 --> 00:26:59,910
jekk I stenna twil biżżejjed, din il-funzjoni
getstring hija se tikseb string

571
00:26:59,910 --> 00:27:04,060
mill-utent, li huwa preżumibbilment ittajpjar
it out fuq it-tastiera tagħhom, u

572
00:27:04,060 --> 00:27:08,090
imbagħad, meta inti getstring isir jkollna
dawk il-karattri mill-utent

573
00:27:08,090 --> 00:27:14,080
u l-ħażna tagħhom fi string, li
funzjoni, getstring, huwa se jkollu

574
00:27:14,080 --> 00:27:17,990
lesta għalija xi output li jiena
tmur sabiex tkun irkuprata permezz ta 'l-

575
00:27:17,990 --> 00:27:19,470
operatur assenjazzjoni.

576
00:27:19,470 --> 00:27:25,390
>> U jekk immur, tabilħaqq, fid-output
hawn, Obosi għandha ġenerożament

577
00:27:25,390 --> 00:27:29,900
sehem, mingħajr ma jkunu jafu dan
javvanza, bil-kitba isimha fuq dan

578
00:27:29,900 --> 00:27:33,100
varjabbli, li qed tirrappreżenta
string.

579
00:27:33,100 --> 00:27:35,640
Issa, l-operatur assenjazzjoni ifisser, anki
għalkemm dan jista 'jħossu ftit

580
00:27:35,640 --> 00:27:38,790
żejda, I attwalment do bżonn
jagħmlu kopja tiegħi stess ta 'dan.

581
00:27:38,790 --> 00:27:40,700
Minħabba min-naħa tax-xellug
ġenb - Whoops! -

582
00:27:40,700 --> 00:27:45,760
avviż li I essenzjalment ikollhom string
isem fuq in-naħa tax-xellug.

583
00:27:45,760 --> 00:27:48,280
Hekk jien wkoll ser tagħmel
kopja tiegħi stess ta 'dan.

584
00:27:48,280 --> 00:27:50,990
U dan huwa daqsxejn ta 'gidba abjad,
għaliex aħna ser tara fil-ġimgħa jew tnejn ta

585
00:27:50,990 --> 00:27:54,100
żmien li kordi mhumiex attwalment
dak li jidher li jkun.

586
00:27:54,100 --> 00:27:56,700
>> Iżda għal issa, hawnhekk huwa l-valur tar-ritorn.

587
00:27:56,700 --> 00:28:00,160
Hawnhekk huwa kopja tiegħi stess ta 'dan wara
jużaw l-operatur assenjazzjoni.

588
00:28:00,160 --> 00:28:01,790
U issa, dak li nixtieq do jmiss?

589
00:28:01,790 --> 00:28:04,080
Issa għandna t-tieni
ta 'żewġ linji ta' kodiċi.

590
00:28:04,080 --> 00:28:05,640
So I issa tixtieq li sejħa printf.

591
00:28:05,640 --> 00:28:08,500
Ejja nippretendu issa li l-iswed
kaxxa huwa lura mill-ġdid li jkunu

592
00:28:08,500 --> 00:28:10,210
printf u mhux getstring.

593
00:28:10,210 --> 00:28:12,200
>> Printf din id-darba se
jieħdu kemm argumenti?

594
00:28:12,200 --> 00:28:14,890

595
00:28:14,890 --> 00:28:16,770
Sabiex tfittex, huwa simili tnejn.

596
00:28:16,770 --> 00:28:18,860
Hemm żewġ virgoli fil hemm, iżda
waħda minn dawk virgoli, huwa

597
00:28:18,860 --> 00:28:20,220
ġewwa tal-kwotazzjonijiet.

598
00:28:20,220 --> 00:28:23,190
Allura l-ewwel argument huwa litteralment
se jkun dan.

599
00:28:23,190 --> 00:28:31,850
H-E-L-L-O,, comma-mija
s, backslash-n.

600
00:28:31,850 --> 00:28:36,560
U issa jien jipprovdi mhux waħda argument,
iżda żewġ argumenti għall printf.

601
00:28:36,560 --> 00:28:39,530
>> U x'hemm printf suppost tagħmel ma '
dawn iż-żewġ inputs wara I jgħaddu minnhom

602
00:28:39,530 --> 00:28:42,050
bħala argumenti?

603
00:28:42,050 --> 00:28:45,360
Huwa suppost li tieħu t-tieni ta '
minnhom, li I imsejħa isem, sabiex il-

604
00:28:45,360 --> 00:28:48,660
tieni biċċa karta I kiteb out
mument ilu huwa msejjaħ isem.

605
00:28:48,660 --> 00:28:53,550
Huwa ser plug tal-valur ġewwa
ta 'dak il-varjabbli fil-placeholder,

606
00:28:53,550 --> 00:28:58,310
% S, b'tali mod li, għal darb'oħra, fil-li ftit mument
ħin, aħna se tara effett sekondarju ta '

607
00:28:58,310 --> 00:29:04,180
Wara li sejħet printf, fejn issa aħna
tara mhux "hello, dinja," iżda "hello,

608
00:29:04,180 --> 00:29:04,710
Obosi. "

609
00:29:04,710 --> 00:29:08,730
>> Allura rawnd kbir ta 'applause għall-tnejn
voluntiera tagħna, wieħed biss minnhom kien jaf

610
00:29:08,730 --> 00:29:12,010
dan ikun jiġri.

611
00:29:12,010 --> 00:29:12,990
Kull dritt.

612
00:29:12,990 --> 00:29:16,480
Allura, forsi, sempliċi bħal dik,
ċertament, jekk int diġà familjari

613
00:29:16,480 --> 00:29:20,190
ma 'tali, nisperaw li int qatt se
ninsew li viżwali partikolari ta 'kif

614
00:29:20,190 --> 00:29:21,220
funzjonijiet xogħol.

615
00:29:21,220 --> 00:29:23,000
>> Allura hemm aktar minn sempliċiment getstring.

616
00:29:23,000 --> 00:29:26,020
Ġewwa tal-librerija CS50, hemm
mazz sħiħ ta 'funzjonijiet, li kollha

617
00:29:26,020 --> 00:29:29,510
huma kapitalizzati biss biex jagħmilha ċara
li aħna kiteb dawn il-funzjonijiet.

618
00:29:29,510 --> 00:29:33,610
Tipikament, fis-C, kważi kull oħra
funzjoni inti ser tuża huwa zghar.

619
00:29:33,610 --> 00:29:36,190
Iżda aħna deliberatament tuża ittri kapitali
biss biex jagħmlu ċar li dawn

620
00:29:36,190 --> 00:29:39,880
huma roti tat-taħriġ ta 'tipi li aħna ser
użu għal ftit ftit ġimgħat li

621
00:29:39,880 --> 00:29:42,890
jissimplifikaw il-proċess ta 'jkollna
input mill-utent.

622
00:29:42,890 --> 00:29:46,740
>> Il-librerija CS50 ma tagħmel xejn
li intom stess ma setgħux jagħmlu mill

623
00:29:46,740 --> 00:29:50,230
biss bl-użu kodiċi C minn
textbook oldschool.

624
00:29:50,230 --> 00:29:53,310
Iżda, għal darb'oħra, aħna jużawhom bħala taħriġ
roti ta 'tip għal ftit ftit

625
00:29:53,310 --> 00:29:57,250
ġimgħat sabiex inkunu nistgħu jeħles mill-
kumplessità li inti ser dalwaqt tifhem

626
00:29:57,250 --> 00:30:00,460
yourself ta 'kif isir xi ħaġa bħala
relattivament sempliċi daqs jkollna

627
00:30:00,460 --> 00:30:02,080
input mill-utent.

628
00:30:02,080 --> 00:30:05,540
>> Allura taf li inti ser ikollhom aċċess
li getchar, GetDouble -

629
00:30:05,540 --> 00:30:06,050
doppju.

630
00:30:06,050 --> 00:30:07,050
What's - u mbagħad GetFloat.

631
00:30:07,050 --> 00:30:07,600
X'hemm float?

632
00:30:07,600 --> 00:30:09,382
Nibdew hemmhekk.

633
00:30:09,382 --> 00:30:10,600
>> STUDENT: [inaudible].

634
00:30:10,600 --> 00:30:10,790
>> DAVID Malan: Yeah.

635
00:30:10,790 --> 00:30:12,120
Huwa numru ma 'punt deċimali.

636
00:30:12,120 --> 00:30:15,930
Allura billi int huwa integer, li
huwa biss numru b'0 sa 9,

637
00:30:15,930 --> 00:30:18,940
xi numru ta 'repetizzjonijiet tiegħu,
a float hija xi ħaġa

638
00:30:18,940 --> 00:30:20,100
ma 'punt deċimali.

639
00:30:20,100 --> 00:30:26,090
U doppja, sadanittant, hija wkoll
in-numru ma 'punt deċimali, iżda aktar

640
00:30:26,090 --> 00:30:28,160
numri wara l-punt deċimali
punt, potenzjalment.

641
00:30:28,160 --> 00:30:30,040
>> Allura aħna ser terġa 'lura għal dan qabel twil.

642
00:30:30,040 --> 00:30:34,560
Imma tipikament, kull wieħed minn dawn it-tipi ta '
data, kull wieħed minn dawn it-tipi ta 'varjabbli

643
00:30:34,560 --> 00:30:39,380
li librerija bħal tagħna jistgħu jirritornaw għall
għalik, uża numri differenti ta 'bits għal

644
00:30:39,380 --> 00:30:40,290
jaħżnu l-informazzjoni.

645
00:30:40,290 --> 00:30:43,910
Tipikament, Char, li ifisser biss
karattru wieħed, użi 8 bits.

646
00:30:43,910 --> 00:30:47,490
U li attwalment konsistenti mal tagħna
byte ta 'voluntiera aħħar ġimgħa li

647
00:30:47,490 --> 00:30:50,410
ħarāu u rappreżentat wieħed
Karattru ASCII fi żmien.

648
00:30:50,410 --> 00:30:51,850
Allura Char huwa 8 bits.

649
00:30:51,850 --> 00:30:54,430
>> A float jiġri li jkun
32 bits, tipikament.

650
00:30:54,430 --> 00:30:59,230
U doppja, kif inti tista raden, huwa
attwalment 64 bits, li huwa biss aktar,

651
00:30:59,230 --> 00:31:01,360
li jfisser li inti jista 'jkollhom akbar
numri jew aktar preċiżjoni.

652
00:31:01,360 --> 00:31:03,000
Iżda għal darb'oħra, aktar fuq dak iż-żmien ieħor.

653
00:31:03,000 --> 00:31:06,550
GetLongLong, sadanittant, għalkemm stupidly
msemmija, huwa verament ftit

654
00:31:06,550 --> 00:31:10,770
numru sħiħ li s darbtejn akbar, darbtejn
twil, potenzjalment, bħala regolari

655
00:31:10,770 --> 00:31:12,940
numru sħiħ, 64 bits minflok 32.

656
00:31:12,940 --> 00:31:14,560
U GetString aħna kont qed tuża.

657
00:31:14,560 --> 00:31:18,870
>> Iżda jirriżulta, fil-librerija CS50,
li huwa implimentat, kif Ser naraw, fil

658
00:31:18,870 --> 00:31:23,560
il-forma taż-żewġ fajls, li waħda minnhom
huwa msejjaħ cs50.h, għandu tnejn l-oħra

659
00:31:23,560 --> 00:31:24,770
tipi ta 'data fiha.

660
00:31:24,770 --> 00:31:29,700
Booleans ma jeżistux fil C. Tista '
jissimulaw minnhom bi ftit użu 0s u 1s

661
00:31:29,700 --> 00:31:30,850
matul programmi tiegħek.

662
00:31:30,850 --> 00:31:35,500
Iżda aħna fil-librerija CS50 ħolqu
is-simboli "vera" u "false"

663
00:31:35,500 --> 00:31:38,580
biex jirrappreżentaw 1 u 0 hekk inti ma
għandek xi ħaġa kodiċi hard

664
00:31:38,580 --> 00:31:39,810
litteralment bħal 1 u 0.

665
00:31:39,810 --> 00:31:40,980
Iżda aħna ser tara dawk mill-ġdid.

666
00:31:40,980 --> 00:31:42,330
>> String, wisq, ma teżistix.

667
00:31:42,330 --> 00:31:44,520
U hu għalhekk li semmejt huwa
daqsxejn ta 'gidba abjad għal issa.

668
00:31:44,520 --> 00:31:46,660
Iżda aħna ser qoxra lura li
saff qabel twil.

669
00:31:46,660 --> 00:31:49,540
Iżda għal issa, string hija
sekwenza ta 'karattri.

670
00:31:49,540 --> 00:31:51,790
>> Sadanittant, fis-C, inti tabilħaqq
għandhom tipi differenti ta 'dejta.

671
00:31:51,790 --> 00:31:53,200
Avviż dawn huma zghar.

672
00:31:53,200 --> 00:31:56,960
Allura l-funzjonijiet inti raw mument ilu
huma funzjonijiet miktuba minn CS50 li

673
00:31:56,960 --> 00:32:02,310
se terġa 'lura lilek valur li jaqa'
f'waħda minn dawn il-kategoriji.

674
00:32:02,310 --> 00:32:06,730
>> A iqarrqu folji koppja biss għall-pjanti
iż-żerriegħa hawn. printf ma biss

675
00:32:06,730 --> 00:32:08,600
tieħu% s bħala placeholders.

676
00:32:08,600 --> 00:32:13,490
Huwa jieħu% d għall interi deċimali,
jew% i taħdem ukoll.

677
00:32:13,490 --> 00:32:19,450
% F f'wiċċ l-ilma valuri tal-punti. % C hija għal
a char, jekk inti tixtieq li biss plagg wieħed

678
00:32:19,450 --> 00:32:23,510
karattru fi string preformatted
simili aħna kont qed tagħmel, inti tista 'tuża% c.

679
00:32:23,510 --> 00:32:28,490
>> U mbagħad, xi ftit annoyingly,% LLD hija
għal twil, numru sħiħ deċimali twil,

680
00:32:28,490 --> 00:32:31,050
ifisser biss li jekk għandek bżonn verament
Numru kbir u inti qed tuża xi ħaġa

681
00:32:31,050 --> 00:32:35,450
imsejħa twil twil, li aħna ser jidħlu
lura fil-pset, inti tista 'tuża% LLD li

682
00:32:35,450 --> 00:32:40,700
tell printf, plug in a big verament
integer hawnhekk permezz tat-tieni tagħha jew

683
00:32:40,700 --> 00:32:41,830
xi argument ieħor.

684
00:32:41,830 --> 00:32:45,700
>> U fl-aħħarnett, I wiegħed li
hemm ħarba oħra ftit

685
00:32:45,700 --> 00:32:47,670
sekwenzi li jappoġġja printf.

686
00:32:47,670 --> 00:32:49,160
Rajna backslash-n.

687
00:32:49,160 --> 00:32:50,510
Backslash-r inti tista 'tara.

688
00:32:50,510 --> 00:32:51,780
Huwa tip ta 'ħaġa qodma l-iskola.

689
00:32:51,780 --> 00:32:55,920
Jekk inti qatt jintużaw snin typewriter reali
ilu u inti jinġibed fuq il-krank

690
00:32:55,920 --> 00:32:59,810
li mhux biss jiddawwar-rota li
jċaqalqu l-lineup, li jkun mexxa wkoll l-

691
00:32:59,810 --> 00:33:03,730
ħaġa sħiħa it-triq kollha lura fuq biex
ix-xellug, ukoll, backslash-r biss

692
00:33:03,730 --> 00:33:06,480
essenzjalment jiċċaqlaq cursor tiegħek lura
il-bidu tal-linja

693
00:33:06,480 --> 00:33:07,830
mingħajr ma jiċċaqlaq l-isfel.

694
00:33:07,830 --> 00:33:09,780
Iżda għal darb'oħra, aktar fuq li,
forsi, fil-futur.

695
00:33:09,780 --> 00:33:13,670
>> Backslash-kwotazzjoni, kwotazzjoni backslash-doppju,
backslash-backslash huwa l-

696
00:33:13,670 --> 00:33:16,600
soluzzjoni għall-riddle ftit żgħira
I allużjoni għall preċedenti.

697
00:33:16,600 --> 00:33:18,920
U backslash-0 huwa attwalment
pjuttost interessanti.

698
00:33:18,920 --> 00:33:21,470
Iżda aħna ser terga 'lura
li qabel twil.

699
00:33:21,470 --> 00:33:25,640
>> So let me jmorru fil, issa, il-CS50
apparat, u ejja attwalment do a

700
00:33:25,640 --> 00:33:28,930
malajr tisħon ma 'wieħed mill-eżempji
aħna ma diġà u mbagħad jimxu fuq

701
00:33:28,930 --> 00:33:31,160
xi ftit aktar kumplessa.

702
00:33:31,160 --> 00:33:34,980
Mela jekk jien tiftaħ program tiegħi
imsejħa gedit -

703
00:33:34,980 --> 00:33:36,840
dan huwa editur grafika tiegħi.

704
00:33:36,840 --> 00:33:38,460
U nista 'tagħmel dan -

705
00:33:38,460 --> 00:33:39,820
let me qrib li tieqa hemm -

706
00:33:39,820 --> 00:33:42,720
permezz ta 'din l-ikona stabbiliti hawn,
gedit, fil-qiegħ tax-xellug

707
00:33:42,720 --> 00:33:44,170
kantuniera li jmiss għall-menu.

708
00:33:44,170 --> 00:33:48,670
>> Jien ser jimxi 'l quddiem u tavvanza, u
jiffranka dan l-eżempju fi, ngħidu aħna, John

709
00:33:48,670 --> 00:33:49,660
Folder Harvard.

710
00:33:49,660 --> 00:33:52,690
Folder John Harvard huwa biss dar tiegħu
direttorju fejn kollha ta 'fajls tiegħu jgħixu

711
00:33:52,690 --> 00:33:53,340
b'kontumaċja.

712
00:33:53,340 --> 00:33:58,410
U jien ser jiffrankaw dan bħala
fajl imsejjaħ bonjour-0.c.

713
00:33:58,410 --> 00:34:01,260
U jien għażilt dan l-isem biss u għalhekk
linji up bil-kodiċi tal-kampjun fuq il-

714
00:34:01,260 --> 00:34:04,210
website kors u fil-
YouTube videos online.

715
00:34:04,210 --> 00:34:06,320
>> Allura issa jien ser jibdew
jiktbu ewwel programm tiegħi.

716
00:34:06,320 --> 00:34:08,469
Let me zoom fl għal-leġibbiltà.

717
00:34:08,469 --> 00:34:12,760
U jien ser jimxi 'l quddiem u jgħidu int
null prinċipali, li huwa biss bħal dik

718
00:34:12,760 --> 00:34:14,900
biċċa puzzle isfar li
jibda 'programm.

719
00:34:14,900 --> 00:34:18,290
I gotten fil-vizzju fuq il-
snin ta 'ftuħ Brace kaboċċi tiegħi, imbagħad

720
00:34:18,290 --> 00:34:22,000
wkoll jagħlquha u mbagħad tmur lura għall-
fejn I tixtieq li tqiegħed kodiċi tiegħi, biss

721
00:34:22,000 --> 00:34:24,630
minħabba li jgħin lili żżomm kollox
bilanċjat, speċjalment fir tiegħi

722
00:34:24,630 --> 00:34:25,880
programm gets twil.

723
00:34:25,880 --> 00:34:29,239
>> U issa, fil hawn, jien ser jimxi 'l quddiem
u jgħidu, printf, ikkwota unquote,

724
00:34:29,239 --> 00:34:34,330
bonjour dinja, backslash-n, kwotazzjoni qrib,
parentesi qrib, b'waqfa u virgola.

725
00:34:34,330 --> 00:34:38,100
Hekk jien biss tirrepeti dak kollu konna
ilhom jieħdu għal mogħtija s'issa.

726
00:34:38,100 --> 00:34:39,270
Issa jien ser zoom out.

727
00:34:39,270 --> 00:34:43,030
>> U dan tieqa terminal stabbiliti hawn, liema
am I permessi li jagħmlu f'dan il-black

728
00:34:43,030 --> 00:34:44,389
u twieqi abjad?

729
00:34:44,389 --> 00:34:46,977
Dak li nista 'tużah għall?

730
00:34:46,977 --> 00:34:49,770
Allura dan huwa fejn I run jikkmanda u
fejn nista 'tiġbor l-affarijiet.

731
00:34:49,770 --> 00:34:50,620
U jien ser jżommha sempliċi.

732
00:34:50,620 --> 00:34:52,780
Jien ser tuża programm
imsejħa Għamla, li mhuwiex

733
00:34:52,780 --> 00:34:54,020
teknikament kompilatur.

734
00:34:54,020 --> 00:34:56,360
Imsejjaħ clang l-kompilatur imma
aħna ser terga 'lura għal li fil-

735
00:34:56,360 --> 00:34:57,190
ġimgħa jew darba tnejn ta.

736
00:34:57,190 --> 00:35:03,410
>> Għal issa, jien biss ser tagħmel tip
bonjour-0, Imma dawk minnkom li kienu

737
00:35:03,410 --> 00:35:07,050
jitqabblu fl-imħuħ tiegħek liema I biss
ittajpjat għal dak I għandu jkollhom ittajpjat jista

738
00:35:07,050 --> 00:35:10,180
jafu diġà li għamilt
xi ħaġa ħażina hawn.

739
00:35:10,180 --> 00:35:12,160
Issa, hemm b'mod ċar xi żbalji.

740
00:35:12,160 --> 00:35:16,742
Qabel I anke tħares lejn dak li huma, kull
ħsibijiet dwar dak li għamilt ħażin?

741
00:35:16,742 --> 00:35:18,590
>> STUDENTI: [INTERPOSING VUĊI].

742
00:35:18,590 --> 00:35:18,840
>> DAVID Malan: Yeah.

743
00:35:18,840 --> 00:35:20,640
Jien nieqsa fajl tal-header tal-librerija.

744
00:35:20,640 --> 00:35:24,240
Kwalunkwe ta 'dawn il-fajls. H huma msejħa header
fajls, u huma kollettivament

745
00:35:24,240 --> 00:35:25,680
jappartjenu għal affarijiet imsejħa libreriji.

746
00:35:25,680 --> 00:35:28,030
Libreriji huma biss biċċiet ta 'kodiċi
li nies oħra kiteb.

747
00:35:28,030 --> 00:35:32,140
Allura l-[standard? i?] librerija hija
ġbir ta 'fajls li jkun fihom kodiċi

748
00:35:32,140 --> 00:35:33,330
li nies oħra kiteb.

749
00:35:33,330 --> 00:35:34,820
>> Hekk jien nieqsa li.

750
00:35:34,820 --> 00:35:36,520
Allura għaliex jien jkollna żball?

751
00:35:36,520 --> 00:35:40,840
Well, let me iscroll back up fl
tieqa terminal tiegħi hawn.

752
00:35:40,840 --> 00:35:44,310
U sfortunatament, fis-C, bħal fil-lott ta '
ipprogrammar ta 'lingwi, speċjalment

753
00:35:44,310 --> 00:35:47,830
jekk huwa ġdid kollu li inti, l-iżball
messaġġi huma preċiżi, iżda dawn qed wkoll

754
00:35:47,830 --> 00:35:48,620
pjuttost mistur.

755
00:35:48,620 --> 00:35:51,720
U l-iżball hawn, bl-aħmar, huwa
"Impliċitament tiddikjara funzjoni librerija

756
00:35:51,720 --> 00:35:57,660
printf tat-tip, "u mbagħad scrolls
mal-linja li jmiss, "int const char *,

757
00:35:57,660 --> 00:36:00,220
... "Huwa biss gets verament
kbira malajr.

758
00:36:00,220 --> 00:36:04,420
>> Imma dak li għandek tibda tagħmel, jekk,
għal darb'oħra, ġodda kollha ta 'dan, huwa biss biex

759
00:36:04,420 --> 00:36:06,010
tibda biex tfittex keywords.

760
00:36:06,010 --> 00:36:08,770
Ovvjament, I ma jista 'jifhmu nofs
tal-kliem jien jaraw għadha biss.

761
00:36:08,770 --> 00:36:10,140
Inti se, għalkemm, fil-ħin ta 'ġimgħa.

762
00:36:10,140 --> 00:36:11,230
Imma nara printf.

763
00:36:11,230 --> 00:36:14,310
U li għandha tibda, qabel twil, li
jog memorja tiegħek, id-dritt, printf.

764
00:36:14,310 --> 00:36:15,210
Xi ħaġa ħażin ma printf.

765
00:36:15,210 --> 00:36:16,580
Did I jespliċitaw hija żbaljata?

766
00:36:16,580 --> 00:36:18,130
Le, ma look like - oh.

767
00:36:18,130 --> 00:36:21,350
I ma tistax tużah sakemm I jgħallmu
l-kumpilatur li dan jeżisti.

768
00:36:21,350 --> 00:36:25,220
U għalhekk, għal darb'oħra, ma tmurx instincts tiegħek,
anki jekk inti ma attwalment jifhmu

769
00:36:25,220 --> 00:36:26,510
l-messaġġi ta 'żball attwali.

770
00:36:26,510 --> 00:36:30,240
>> U fil-fatt, is-soluzzjoni hawnhekk huwa li biss
inkluża fil-quċċata tal-fajl

771
00:36:30,240 --> 00:36:34,340
bħal dik, resaving file tiegħi ma
Kontroll-S jew il-menu 'File.

772
00:36:34,340 --> 00:36:36,730
U jekk I issa jmorru lura stabbiliti hawn,
Jien ser għal dan ċar.

773
00:36:36,730 --> 00:36:39,150
Kontroll-L huwa biss mod sabiħ
ċar li l-iskrin.

774
00:36:39,150 --> 00:36:44,870
U allura jien ser tip "jagħmlu bonjour
0 "Daħħal, u issa I still tara

775
00:36:44,870 --> 00:36:47,710
sekwenza cryptic ta 'simboli, iżda
aħna ser terga 'lura għal dan.

776
00:36:47,710 --> 00:36:49,230
Dak hu Agħmel qed tagħmel għalik.

777
00:36:49,230 --> 00:36:52,590
Huwa awtomatizzazzjoni-proċess tat-teħid
kmand pjuttost annoying li jinvolvi

778
00:36:52,590 --> 00:36:54,050
Clang, il-kompilatur attwali.

779
00:36:54,050 --> 00:36:57,460
Imma l-fatt li sibt ebda żbalji ifisser
li dan il-ħaġa għandha taħdem.

780
00:36:57,460 --> 00:37:00,630
>> Hekk jien issa se tagħmel -
let me zoom mill-ġdid -

781
00:37:00,630 --> 00:37:07,070
./hello-0 Daħħal, u tabilħaqq, nara
"Hello, dinja." Mela ejja issa itejbu

782
00:37:07,070 --> 00:37:12,105
dan dejjem hekk ftit biss biex jirreplikaw
l-passi aħna maħsub.

783
00:37:12,105 --> 00:37:15,370
Jien ser tibdel isem dan ma
Save As biex hello1.c.

784
00:37:15,370 --> 00:37:20,300
U issa jien ser tiddikjara varjabbli
imsejħa isem, isem hekk string,

785
00:37:20,300 --> 00:37:23,420
u jien ser jistabbilixxu dan il-
valur tal-kwotazzjoni-unquote

786
00:37:23,420 --> 00:37:27,030
D-A-V-I-D semicolon close-kwotazzjoni.

787
00:37:27,030 --> 00:37:31,150
U issa jien ser tissostitwixxi "dinja"
ma 'dak placeholder għal string?

788
00:37:31,150 --> 00:37:32,200
% S.

789
00:37:32,200 --> 00:37:35,040
>> U issa, kemm argumenti għandhom
printf jieħdu dan iż-żmien?

790
00:37:35,040 --> 00:37:35,700
Allura tnejn.

791
00:37:35,700 --> 00:37:37,090
So I tmur barra tal-kwotazzjonijiet.

792
00:37:37,090 --> 00:37:39,330
I tip "isem" wara virgola.

793
00:37:39,330 --> 00:37:41,550
Imma jien ghamilt xi ħaġa
inkella ħażin dan iż-żmien.

794
00:37:41,550 --> 00:37:43,940
Imma ejja nassumu li għamilt ma
tirrealizza li għadu.

795
00:37:43,940 --> 00:37:44,910
Let me go up here.

796
00:37:44,910 --> 00:37:48,850
>> U avviż, wisq, jien jkollna ftit
bored ta 'tajping "jagħmlu bonjour 0" il-

797
00:37:48,850 --> 00:37:50,180
ħin, "jagħmlu" u dan kollu.

798
00:37:50,180 --> 00:37:53,270
Għalhekk, jirriżulta, fil Linus inti tista
spiss hit-vleġġa Up fuq tiegħek

799
00:37:53,270 --> 00:37:56,850
keyboard, u inti tista 'attwalment iscroll
kollha permezz ta 'l-kmandi li stajt

800
00:37:56,850 --> 00:37:58,830
esegwiti preċedenti għal ftit issa.

801
00:37:58,830 --> 00:38:02,040
Mela jekk jien tagħmel dan, Up, Up,
hemm tagħmel bonjour 0.

802
00:38:02,040 --> 00:38:02,610
Ma rridx li.

803
00:38:02,610 --> 00:38:05,450
I biss trid tibdel dak li
bonjour 1 dan iż-żmien, Ikteb.

804
00:38:05,450 --> 00:38:07,620
Eventwalment, li se
jiffrankaw xi żmien.

805
00:38:07,620 --> 00:38:08,150
>> Kull dritt.

806
00:38:08,150 --> 00:38:09,520
Sfortunatament, hemm huwa żball.

807
00:38:09,520 --> 00:38:10,980
So let me iscroll.

808
00:38:10,980 --> 00:38:13,120
Dan qisu I really
butchered dan il-programm.

809
00:38:13,120 --> 00:38:16,530
I mean, my god, huwa żewġ linji ta 'kodiċi,
u 10 linji ta 'l-iżbalji tiegħu.

810
00:38:16,530 --> 00:38:18,800
Iżda tħares lejn il-quċċata waħda ewwel.

811
00:38:18,800 --> 00:38:21,640
Użu ta 'sekwenza identifikatur mhux iddikjarat.

812
00:38:21,640 --> 00:38:23,270
Did I tfisser standard i n?

813
00:38:23,270 --> 00:38:23,930
Nru I ma.

814
00:38:23,930 --> 00:38:24,940
I fisser string.

815
00:38:24,940 --> 00:38:29,390
>> Iżda fejn huwa l-varjabbli string
tip bħal dik iddikjarata, dd ngħidu?

816
00:38:29,390 --> 00:38:30,730
Allura huwa fil-CS50-librerija.

817
00:38:30,730 --> 00:38:33,740
Għalhekk mhuwiex biżżejjed, f'dawn ewwel
ftit ġimgħat, biss għall-użu

818
00:38:33,740 --> 00:38:34,860
dak C tagħtina.

819
00:38:34,860 --> 00:38:38,120
Jien ukoll se jmorru up hawn, u jien
tista poġġih fuq jew taħt, imma jien ser

820
00:38:38,120 --> 00:38:40,340
biss iżommu alfabetiku
li żżomm affarijiet ordnat.

821
00:38:40,340 --> 00:38:43,470
Jien ser jinkludu cs50.h,
li huwa installat minn qabel għall-

822
00:38:43,470 --> 00:38:44,900
inti fuq il-appliance CS50.

823
00:38:44,900 --> 00:38:47,640
U huwa sors miftuħ, hekk anke nies
fuq l-internet jistgħu jużawh fuq tagħhom

824
00:38:47,640 --> 00:38:48,450
kompjuters stess.

825
00:38:48,450 --> 00:38:50,700
Imma niġu mal-appliance CS50.

826
00:38:50,700 --> 00:38:55,320
>> Allura issa let me jmorru lura u recompile
dan ma jagħmel bonjour 1.

827
00:38:55,320 --> 00:38:55,710
Kkritikat dan.

828
00:38:55,710 --> 00:38:57,240
Still żball ieħor.

829
00:38:57,240 --> 00:38:59,370
Let me iscroll sa l-ewwel, għalkemm.

830
00:38:59,370 --> 00:39:00,630
Dan wieħed huwa kumpless ftit.

831
00:39:00,630 --> 00:39:03,830
Karattru multi-karattru kostanti.

832
00:39:03,830 --> 00:39:04,890
Li mhux tgħin me.

833
00:39:04,890 --> 00:39:08,220
Iżda avviż, clang hija inqas ftit
bit deċenti, fejn bi ftit

834
00:39:08,220 --> 00:39:11,890
aħdar caret simbolu, huwa qal
hawnhekk huwa fejn I invitat up.

835
00:39:11,890 --> 00:39:16,160
Għaliex huwa tipponta, ma 'dak ftit
aħdar vleġġa, għall-kwotazzjoni waħda li jkun imiss

836
00:39:16,160 --> 00:39:18,290
l-isem tiegħi?

837
00:39:18,290 --> 00:39:20,880
>> Allura dan huwa wieħed mill-affarijiet li inti biss
jidraw, speċjalment jekk inti kont qed

838
00:39:20,880 --> 00:39:23,980
programmazzjoni Python, jew JavaScript,
jew lingwi oħra fejn dan id-dettall

839
00:39:23,980 --> 00:39:24,560
ma jimpurtax.

840
00:39:24,560 --> 00:39:25,740
Fl C, ma jimpurtax.

841
00:39:25,740 --> 00:39:29,520
Jekk inti qed jiddikjaraw string, li hija
sekwenza ta '0 jew aktar karattri,

842
00:39:29,520 --> 00:39:32,280
inti fil-fatt għandhom jużaw kwotazzjonijiet doppja.

843
00:39:32,280 --> 00:39:36,670
So I attwalment bżonn għall-bidla dan lura
li tiftaħ kwotazzjoni, qrib kwotazzjoni, ma

844
00:39:36,670 --> 00:39:37,800
kwotazzjonijiet doppja.

845
00:39:37,800 --> 00:39:41,610
Kwotazzjonijiet uniku do jkollhom post tagħhom, iżda
biss meta inti qed tuża individwali

846
00:39:41,610 --> 00:39:44,100
Chars, iżda aktar fuq dak iż-żmien ieħor.

847
00:39:44,100 --> 00:39:46,550
Għal issa, il-kwotazzjonijiet doppja
huma meħtieġa.

848
00:39:46,550 --> 00:39:50,460
>> Allura issa, let me jmorru lura għall terminal tiegħi
tieqa, jagħmlu bonjour 1.

849
00:39:50,460 --> 00:39:51,450
U li huwa kunfidenti?

850
00:39:51,450 --> 00:39:53,800
Huwa dan il-programm issa se
biex jikkompilaw korrett?

851
00:39:53,800 --> 00:39:58,250

852
00:39:58,250 --> 00:39:58,540
OK.

853
00:39:58,540 --> 00:39:59,780
Allura tlieta minna jaħsbu dan.

854
00:39:59,780 --> 00:40:00,280
Kull dritt.

855
00:40:00,280 --> 00:40:01,190
Ikteb.

856
00:40:01,190 --> 00:40:02,440
U fil-fatt għamlet.

857
00:40:02,440 --> 00:40:05,130
Allura hemm l-ebda żbalji f'dan iż-żmien, anke
għalkemm dan il-programm gotten daqsxejn

858
00:40:05,130 --> 00:40:05,840
aktar kumplessi.

859
00:40:05,840 --> 00:40:10,110
Jekk I do issa dot mmejla bonjour 1, Ikteb,
li għaddej biex jgħidu "bonjour, David."

860
00:40:10,110 --> 00:40:11,750
>> Imma ejja jagħmlu l-tielet iterazzjoni
ta 'dan, fejn il-

861
00:40:11,750 --> 00:40:13,380
programm huwa verament dinamiku.

862
00:40:13,380 --> 00:40:16,770
Let me imorru quddiem u jibdlu l-fajl
isem, biss għall-konsistenza mal-

863
00:40:16,770 --> 00:40:20,410
fajls li inti ser ikollok disponibbli
lilek afterward online.

864
00:40:20,410 --> 00:40:21,620
Ikteb.

865
00:40:21,620 --> 00:40:25,510
U issa jien se jmorru fi u ma
taħżen "David" hard kodifikati hawn.

866
00:40:25,510 --> 00:40:28,826
Liema jista 'nagħmel biex ħafna sempliċement
itejbu dan il-programm?

867
00:40:28,826 --> 00:40:30,520
>> I tista 'sejħa getstring.

868
00:40:30,520 --> 00:40:33,240
Jista 'jkun dak li mhux ovvju ftit huwa
sejjer iseħħ, hekk jien ser

869
00:40:33,240 --> 00:40:38,470
li attwalment żid ieħor linja, printf,
u jgħidu isem, kolon, kwotazzjoni qrib, biss

870
00:40:38,470 --> 00:40:40,790
li jagħti lill-utent fil-pront
fuq l-iskrin.

871
00:40:40,790 --> 00:40:42,980
U issa jien se jmorru hawn, u jien
ser tuża shortcut keyboard tiegħi.

872
00:40:42,980 --> 00:40:47,680
Jien se jmorru Up, Up, u l-bidla
bonjour 1 sa bonjour 2, Ikteb.

873
00:40:47,680 --> 00:40:49,260
U Thankfully, jien jagħmlu progress.

874
00:40:49,260 --> 00:40:52,720
>> U issa jien se jmorru up
biex dot mmejla bonjour u

875
00:40:52,720 --> 00:40:54,690
bidla li għal 2, Ikteb.

876
00:40:54,690 --> 00:40:55,650
U issa program tiegħi -

877
00:40:55,650 --> 00:40:57,700
I ser zoom - huwa jkollna
ftit prettier.

878
00:40:57,700 --> 00:41:02,190
Isem se tkun, ejja ngħidu Rob
dan iż-żmien, Daħħal, hello, Rob.

879
00:41:02,190 --> 00:41:03,260
Nistgħu nagħmlu dan mill-ġdid.

880
00:41:03,260 --> 00:41:05,360
Isem, Lauren, Ikteb.

881
00:41:05,360 --> 00:41:07,820
Isem, Joseph, Ikteb.

882
00:41:07,820 --> 00:41:11,596
Isem, ejja jipprova jkun
diffiċli, Ikteb.

883
00:41:11,596 --> 00:41:12,410
Eh.

884
00:41:12,410 --> 00:41:14,680
Mhuwiex verament bug.

885
00:41:14,680 --> 00:41:16,090
Allura huwa biss ikrah ftit.

886
00:41:16,090 --> 00:41:18,640
Allura forsi nistgħu issolvi din
fil-futur, mhux issa.

887
00:41:18,640 --> 00:41:20,840
>> Imma kif kieku inti istintivament
għanddu indirizzar

888
00:41:20,840 --> 00:41:21,990
dik l-isfida partikolari?

889
00:41:21,990 --> 00:41:23,710
Hija biss jistenna stupid.

890
00:41:23,710 --> 00:41:27,320
Kif inti tevita affarijiet
tfittex stupid?

891
00:41:27,320 --> 00:41:29,890
Allura nistgħu nagħmlu, OK, I sema 'koppja
ta 'affarijiet, kundizzjoni u loop.

892
00:41:29,890 --> 00:41:33,340
Aħna jistgħu jużaw, wieħed, kundizzjoni, biex jikkontrolla
dak huwa t-tul tas-sekwenza

893
00:41:33,340 --> 00:41:34,190
l-utent tana?

894
00:41:34,190 --> 00:41:37,100
U jekk huwa 0, huwa biss nikkwota unquote,
huma biss hit Ikteb, imbagħad

895
00:41:37,100 --> 00:41:38,930
forsi I għandhom Yell fil minnhom
u twassalhom għal darb'oħra.

896
00:41:38,930 --> 00:41:39,970
Imma kif a twassalhom mill-ġdid?

897
00:41:39,970 --> 00:41:44,230
Well, I jinstemgħu wkoll loop, u I jistgħu
tagħmel dan mill-ġdid u għal darb'oħra u għal darb'oħra

898
00:41:44,230 --> 00:41:47,010
wassal lill-utent għall-istess ħaġa.

899
00:41:47,010 --> 00:41:48,880
>> Well, ejja nagħmlu eżempju wieħed ieħor
użu ta 'differenti

900
00:41:48,880 --> 00:41:50,620
funzjoni fil-librerija CS50.

901
00:41:50,620 --> 00:41:52,330
Let me qrib dan il-fajl.

902
00:41:52,330 --> 00:41:53,510
Let me toħloq waħda ġdida.

903
00:41:53,510 --> 00:41:58,510
U jien ser sejħa hija adder.c, sempliċement minħabba
huwa faċli li tagħmel aritmetika sempliċi,

904
00:41:58,510 --> 00:42:00,890
anki jekk dan se jkun kompletament
underwhelming ma 'dak li inti tista' tagħmel

905
00:42:00,890 --> 00:42:02,250
ma 'kull kompjuter moderna.

906
00:42:02,250 --> 00:42:03,750
>> Iżda let me imorru quddiem u issa -

907
00:42:03,750 --> 00:42:10,680
Tgħallimt lezzjoni tiegħi aħħar darba - jinkludu
cs50.h, jinkludu stdio.h, int

908
00:42:10,680 --> 00:42:14,170
null prinċipali, li, għal issa, I ser biss
jieħdu fuq il-fidi għomja, iżda aħna ser tassumi

909
00:42:14,170 --> 00:42:16,380
li se jifhmu dak
dan ifisser qabel twil.

910
00:42:16,380 --> 00:42:21,030
U jien se ngħid xi ħaġa
bħal "tagħti me int."

911
00:42:21,030 --> 00:42:22,140
>> U issa, kif nista 'nikseb int?

912
00:42:22,140 --> 00:42:26,820
Irrid li finalment tiddikjara varjabbli
imsejħa x tat int tip u

913
00:42:26,820 --> 00:42:29,240
jaħżnu fiha integer mill-utent.

914
00:42:29,240 --> 00:42:29,970
Allura li kien f'gidma.

915
00:42:29,970 --> 00:42:35,680
Imma jekk xi ħadd irid biex tipproponi, kif
nista 'tiddikjara imsejħa x integer?

916
00:42:35,680 --> 00:42:36,310
X int.

917
00:42:36,310 --> 00:42:37,430
>> Allura dan huwa verament dak sempliċi.

918
00:42:37,430 --> 00:42:38,240
Agħti me int.

919
00:42:38,240 --> 00:42:39,070
Sejħa hija x.

920
00:42:39,070 --> 00:42:40,580
Issa I użu l-operatur assenjazzjoni.

921
00:42:40,580 --> 00:42:43,400
U kif nista taħżen mill-
ħalla valur tal-utent?

922
00:42:43,400 --> 00:42:47,310
Ma rridx li jsejħu getstring,
ovvjament, iżda pjuttost getint.

923
00:42:47,310 --> 00:42:49,060
Kull argument?

924
00:42:49,060 --> 00:42:49,350
No

925
00:42:49,350 --> 00:42:51,870
Allura huwa miftuħ paren, paren qrib
immedjatament, u mbagħad

926
00:42:51,870 --> 00:42:53,440
virgola tispiċċa l-linja.

927
00:42:53,440 --> 00:42:54,930
>> Issa let me tagħmel dan mill-ġdid.

928
00:42:54,930 --> 00:42:57,070
Agħti me int ieħor.

929
00:42:57,070 --> 00:43:01,850
Din id-darba I ser tagħmel int, ejja
sejħa hija y, ugwali getint.

930
00:43:01,850 --> 00:43:05,060
U issa let me tagħmel xi ħaġa sempliċi super-
bħal xi matematika.

931
00:43:05,060 --> 00:43:14,340
Allura printf, is-somma ta '% d huwa l-
placeholder għal int.

932
00:43:14,340 --> 00:43:20,030
U% d, perjodu, backslash-n.

933
00:43:20,030 --> 00:43:20,360
>> Kull dritt.

934
00:43:20,360 --> 00:43:21,670
Allura li mhux attwalment matematika.

935
00:43:21,670 --> 00:43:25,500
Imma jekk irrid ngħid is-somma ta 'dan
valur plus dan il-valur ugwali din

936
00:43:25,500 --> 00:43:29,320
valur ieħor, kemm argumenti fis
total għandi tkun tagħti printf,

937
00:43:29,320 --> 00:43:30,520
finalment?

938
00:43:30,520 --> 00:43:31,420
Allura erba, id-dritt?

939
00:43:31,420 --> 00:43:33,790
Dan string u mbagħad it-tliet valuri.

940
00:43:33,790 --> 00:43:37,560
Allura x hija l-ewwel nixtieq li jkun
pplaggjata ewwel għat-% d.

941
00:43:37,560 --> 00:43:39,270
y se tkun li jmiss.

942
00:43:39,270 --> 00:43:42,030
>> U issa I tip ta 'tixtieq li jgħidu
z, imma z ma teżistix.

943
00:43:42,030 --> 00:43:43,190
Iżda li mhux big deal.

944
00:43:43,190 --> 00:43:45,440
Minħabba dak li għandek tagħmel istintivament,
speċjalment jekk kellek

945
00:43:45,440 --> 00:43:47,820
graphing calculator, liema do inti tip?

946
00:43:47,820 --> 00:43:48,760
Kif dwar x plus y?

947
00:43:48,760 --> 00:43:50,200
Għalhekk mhuwiex varjabbli attwali.

948
00:43:50,200 --> 00:43:51,820
Huwa biss is-somma ta 'żewġ
varjabbli oħra.

949
00:43:51,820 --> 00:43:53,170
U li perfettament leġittimu.

950
00:43:53,170 --> 00:43:56,630
C ċertament jifhem sempliċi
aritmetika bħal dan.

951
00:43:56,630 --> 00:43:58,450
>> Virgola, jiffrankaw.

952
00:43:58,450 --> 00:44:02,080
Issa let me jinżlu hawn u
tip jagħmel aġent li jżid, Ikteb.

953
00:44:02,080 --> 00:44:04,100
Nuqqas ta 'żball, b'tali mod li l-progress wisq.

954
00:44:04,100 --> 00:44:04,890
Tip aġent li jżid.

955
00:44:04,890 --> 00:44:07,100
U shortcut ieħor keyboard,
jekk tibda niddejjaq

956
00:44:07,100 --> 00:44:08,760
ma 'l-kmandi -

957
00:44:08,760 --> 00:44:12,650
jekk tibda ittajpjar kmand, bħal dot
slash ad, u li fejn tiegħek

958
00:44:12,650 --> 00:44:16,020
dwejjaq kicks, inti tista 'normalment hit
Tab li jkollhom il-kompjuter jintemm l-

959
00:44:16,020 --> 00:44:20,510
mistrieħ tal-frażi għalik jekk mhuwiex
dak ambigwa għandhom jidħlu wara ad.

960
00:44:20,510 --> 00:44:23,950
>> So let me aqbad issa
u tikklikkja Ikteb.

961
00:44:23,950 --> 00:44:27,490
Agħti me int, 1, 2, u
Thankfully, huwa 3.

962
00:44:27,490 --> 00:44:29,900
Imma kif dejjem, ittestjar programmi
m'għandhiex tnaqqas għal

963
00:44:29,900 --> 00:44:30,820
biss tipprova dan darba.

964
00:44:30,820 --> 00:44:35,560
Let me jippruvaw każ kantuniera, bħal negattiv
1, tagħti me 1, u li wieħed

965
00:44:35,560 --> 00:44:36,210
kontrolli out ukoll.

966
00:44:36,210 --> 00:44:38,870
U jien probabilment jridu jagħmlu xi aktar
testijiet rigorużi, imma jien pretty

967
00:44:38,870 --> 00:44:40,630
komdi fejn dan huwa fl.

968
00:44:40,630 --> 00:44:43,110
>> Well, issa ejja jippruvaw programm ieħor
li din id-darba juża

969
00:44:43,110 --> 00:44:44,620
daqsxejn ta 'sintassi oħra.

970
00:44:44,620 --> 00:44:46,100
Let me toħloq fajl ġdid.

971
00:44:46,100 --> 00:44:51,050
I ser sejħa dan conditions0.c għal-linja
up ma 'xi kodiċi online kampjun.

972
00:44:51,050 --> 00:44:55,550
U let me imorru quddiem u tagħmel
jinkludu cs50.h, jinkludu

973
00:44:55,550 --> 00:45:00,320
stdio.h, fil null prinċipali -

974
00:45:00,320 --> 00:45:01,030
OK.

975
00:45:01,030 --> 00:45:01,850
Hemm immorru.

976
00:45:01,850 --> 00:45:03,010
Għandna boilerplate standard tagħna.

977
00:45:03,010 --> 00:45:08,170
>> U din id-darba jien se ngħid printf,
"Nixtieq li int, jekk jogħġbok," biss biex

978
00:45:08,170 --> 00:45:10,030
jagħmlu l-pront ftit
aktar faċli.

979
00:45:10,030 --> 00:45:11,620
U issa nixtieq li tikseb
int mill-utent.

980
00:45:11,620 --> 00:45:15,010
Jien ser sejħa hija n this time, biss
minħabba n tinstema numru.

981
00:45:15,010 --> 00:45:18,140
getint, u issa, liema do
I trid tagħmel magħha?

982
00:45:18,140 --> 00:45:21,640
Ukoll, jekk n hija - u jien ser zoom fl -

983
00:45:21,640 --> 00:45:25,930
jekk n hija akbar minn 0, nixtieq
tagħmel dan li ġej -

984
00:45:25,930 --> 00:45:36,060
printf "Inti qabad numru pożittiv."
Else, jien ser tip printf "You

985
00:45:36,060 --> 00:45:37,870
qabad negattiv

986
00:45:37,870 --> 00:45:39,650
numru. "Kull dritt.

987
00:45:39,650 --> 00:45:44,410
Allura dan il-programm, anki jekk I ma kien
fast, jistenna dritt sintattikament.

988
00:45:44,410 --> 00:45:45,010
Let me tipprova dan.

989
00:45:45,010 --> 00:45:46,890
Kun kundizzjoni 0.

990
00:45:46,890 --> 00:45:47,710
Jidher li jiddekorri.

991
00:45:47,710 --> 00:45:49,230
Kundizzjoni 0, jidħol.

992
00:45:49,230 --> 00:45:51,910
Ejja jagħtih int ta '50.

993
00:45:51,910 --> 00:45:53,160
I telgħet numru pożittiv.

994
00:45:53,160 --> 00:45:54,230
Ejja tipprova mill-ġdid.

995
00:45:54,230 --> 00:45:54,930
Kundizzjoni 0.

996
00:45:54,930 --> 00:45:56,260
Negattiv 50.

997
00:45:56,260 --> 00:45:57,290
I telgħet numru negattiv.

998
00:45:57,290 --> 00:46:00,350
>> Imma issa, let me pick dak li aħna ser iżommu
ssejjaħ każ kantuniera, li huwa aktar

999
00:46:00,350 --> 00:46:04,702
każ interessanti li taħseb
jista 'jagħtik xi problemi, 0.

1000
00:46:04,702 --> 00:46:07,940
Issa, jien pretty żgur dan huwa wieħed ta '
F'dawk il-każijiet fejn kantuniera żero huwa

1001
00:46:07,940 --> 00:46:12,330
la pożittiv u lanqas negattiv, hekk tiegħi
programm, għalkemm sintattikament

1002
00:46:12,330 --> 00:46:15,440
jikkoreġu - huwa jikkompila, hija tmur -
mhuwiex loġikament korretta.

1003
00:46:15,440 --> 00:46:21,050
Allura x'inhu l-jiffissaw sempliċi hawn jekk irrid
li tiskopri, jekk irrid li jimmaniġġjaw n

1004
00:46:21,050 --> 00:46:23,840
egwali għal 0 separatament?

1005
00:46:23,840 --> 00:46:32,980
>> Mela jekk n ikun egwali għal 0, allura nixtieq ngħid
xi ħaġa bħal printf "Inti qabad 0."

1006
00:46:32,980 --> 00:46:33,990
Let me tipprova dan issa.

1007
00:46:33,990 --> 00:46:38,320
Let me jmorru lura hawn, ċara
tieqa tiegħi, u recompile.

1008
00:46:38,320 --> 00:46:38,690
Hm.

1009
00:46:38,690 --> 00:46:39,770
Wieħed żball jiġġeneraw.

1010
00:46:39,770 --> 00:46:41,630
Imma I do inti tixtieq li jiċċekkjaw
jekk n ikun egwali għal 0.

1011
00:46:41,630 --> 00:46:44,230

1012
00:46:44,230 --> 00:46:47,720
>> Għalhekk għal darb'oħra, ħaġa oħra stupid
biex jidraw, sinjal ugwali huwa

1013
00:46:47,720 --> 00:46:48,910
l-operatur assenjazzjoni.

1014
00:46:48,910 --> 00:46:52,240
Allura dan huwa attwalment żball peress li,
teknikament, anki jekk il-kompilatur

1015
00:46:52,240 --> 00:46:56,450
protetti lili mill myself, aħna'd
teknikament ikkupjar 0 fil n, li

1016
00:46:56,450 --> 00:46:57,590
mhuwiex dak li nixtieq.

1017
00:46:57,590 --> 00:47:00,950
Irrid li jittestjaw għall-ugwaljanza
ma ugwali ugwali.

1018
00:47:00,950 --> 00:47:03,390
U hekk li issa jista 'jkun
soluzzjoni aħjar tiegħi.

1019
00:47:03,390 --> 00:47:07,810
>> Let me attwalment resave dan bħal, ngħidu aħna,
conditions1, li jkunu ġodda u mtejba.

1020
00:47:07,810 --> 00:47:10,480
Allura issa jekk I recompile dan,
ikun jagħmel kundizzjonijiet -

1021
00:47:10,480 --> 00:47:16,960
Whoops - jagħmlu conditions1 dot mmejla
conditions1, Daħħal, "Nixtieq li int,

1022
00:47:16,960 --> 00:47:18,760
jekk jogħġbok. "Jien se jmorru
quddiem u tip 50.

1023
00:47:18,760 --> 00:47:19,660
Huwa għadu tajjeb.

1024
00:47:19,660 --> 00:47:21,200
Negattiv 50, għadu tajjeb.

1025
00:47:21,200 --> 00:47:24,920
0, u, tabilħaqq, skoperta
li I telgħet 0.

1026
00:47:24,920 --> 00:47:28,200
>> Allura dak li aktar tista 'issa I ma' dan?

1027
00:47:28,200 --> 00:47:32,280
Well, nistgħu ċertament tagħmel dejjem aktar
affarijiet kumplessi.

1028
00:47:32,280 --> 00:47:37,240
Imma dak I tixtieq tipproponi huwa
li aħna jispiċċaw fuq din in-nota hawnhekk.

1029
00:47:37,240 --> 00:47:41,680
Jekk aħna pull up dan, tkun taf tara, forsi,
cartoons favoriti tal tiegħek

1030
00:47:41,680 --> 00:47:43,326
sal-lum inti tista '
qatt ma fehmu.

1031
00:47:43,326 --> 00:47:46,550

1032
00:47:46,550 --> 00:47:49,520
U li jkunu infurmati dwar il-kwalità tal daħk
għandek tikseb bil ċajt CS.

1033
00:47:49,520 --> 00:47:51,060
Allura dak dwar id-dritt.

1034
00:47:51,060 --> 00:47:54,900
>> Iżda aktar compellingly, ħsibt I d
tagħtina teaser ftit għal It-tnejn.

1035
00:47:54,900 --> 00:47:56,430
Allura aħna ħadthom bdew jużaw interi.

1036
00:47:56,430 --> 00:47:57,510
Imxejna msemmija sufruni.

1037
00:47:57,510 --> 00:48:00,120
Imxejna anke msemmija jirdoppja,
li, għal darb'oħra, jagħtik numri

1038
00:48:00,120 --> 00:48:01,390
wara punti deċimali.

1039
00:48:01,390 --> 00:48:04,230
>> Iżda jirriżulta li sufruni u
jirdoppja, u, verament, kompjuters,

1040
00:48:04,230 --> 00:48:08,470
fundamentalment, ma jistgħux jesprimu
xi valuri preċiż.

1041
00:48:08,470 --> 00:48:12,840
Nafu mill-klassijiet matematika li inti tista '
jkollhom kwalunkwe numru ta 'numri wara l-

1042
00:48:12,840 --> 00:48:13,510
punt deċimali.

1043
00:48:13,510 --> 00:48:16,460
U inti tista 'anki tpoġġi bar vertikali
li jgħidu dawn imorru fuq għal dejjem.

1044
00:48:16,460 --> 00:48:18,810
>> Sfortunatament, inti ma tistax verament
tagħmel dan fil-kompjuter.

1045
00:48:18,810 --> 00:48:20,400
U hekk jinqalgħu każijiet kantuniera.

1046
00:48:20,400 --> 00:48:23,120
Per eżempju, ejja ngħidu li int
tagħmel xi ħaġa finanzjarju.

1047
00:48:23,120 --> 00:48:25,700
Inti qed tagħmel matematika
b'persentaġġi, u

1048
00:48:25,700 --> 00:48:27,030
ma 'dollari u ċenteżmi.

1049
00:48:27,030 --> 00:48:29,230
U dawk ċenteżmi ma
neċessarjament line up.

1050
00:48:29,230 --> 00:48:34,120
Ukoll, jirriżulta li l frazzjonijiet ta '
pennies jistgħu jibdew jammontaw meta

1051
00:48:34,120 --> 00:48:37,250
mmudellata ma 'sistema tal-kompjuter
b'tali mod li għaqlija

1052
00:48:37,250 --> 00:48:39,100
bnedmin jistgħu jieħdu vantaġġ.

1053
00:48:39,100 --> 00:48:42,650
>> U dawk fostkom li għadhom ma bbenefikawx, I d
tixtieq li jtik 30-tieni teaser ta

1054
00:48:42,650 --> 00:48:48,290
a film isbaħ magħrufa bħala Uffiċċju Ispazju,
li se żebgħa stampa ta '

1055
00:48:48,290 --> 00:48:51,205
problema aħna għandu jittratta
ewwel ħaġa nhar it-Tnejn.

1056
00:48:51,205 --> 00:48:53,960
Jekk nistgħu jgħollu l-volum
ftit, I jagħtuk 30

1057
00:48:53,960 --> 00:48:55,495
sekondi ta 'Uffiċċju Ispazju.

1058
00:48:55,495 --> 00:48:55,770
>> [Daqq video]

1059
00:48:55,770 --> 00:48:59,000
>> -I mean, inti, inti ma ġewx juru
up u ikollok biex iżommu xogħol tiegħek.

1060
00:48:59,000 --> 00:49:00,620
>> Attwalment-, jien qed jiġi promoss.

1061
00:49:00,620 --> 00:49:03,240
>> -I tista program virus li theyd
RIP dak il-post off big time.

1062
00:49:03,240 --> 00:49:04,430
>> Well, kif taħdem?

1063
00:49:04,430 --> 00:49:06,782
>> -Kull darba hemm tranżazzjoni bank
fejn l-interess jiġi kkalkulat, u hemm

1064
00:49:06,782 --> 00:49:10,160
eluf kuljum, il-kompjuter truf
up ma 'dawn frazzjonijiet ta' ċenteżmu.

1065
00:49:10,160 --> 00:49:12,030
>> -Imma jien mhux ser
tagħmel xejn illegali.

1066
00:49:12,030 --> 00:49:12,660
>> -Illegali?

1067
00:49:12,660 --> 00:49:15,075
Samir, dan huwa l-Amerika.

1068
00:49:15,075 --> 00:49:16,570
>> -Aħna li naħlef li Alla.

1069
00:49:16,570 --> 00:49:19,070
>> -Jekk ħadd ma jaf dwar dan
iżda us, id-dritt?

1070
00:49:19,070 --> 00:49:21,920
Nru membri tal-familja, l-ebda
girlfriends, ħadd.

1071
00:49:21,920 --> 00:49:22,700
>> -Tal-kors.

1072
00:49:22,700 --> 00:49:23,320
>> -Miftiehma.

1073
00:49:23,320 --> 00:49:24,280
>> -Don tinkwetax, il-bniedem.

1074
00:49:24,280 --> 00:49:25,640
I mhux se tgħid xi ħadd jew.

1075
00:49:25,640 --> 00:49:26,504
>> [Daqq video END]

1076
00:49:26,504 --> 00:49:30,030
>> DAVID Malan: Allura dan, allura, huwa CS50,
li kienet Uffiċċju Ispazju, u kollha se

1077
00:49:30,030 --> 00:49:31,465
jagħmel sens nhar it-Tnejn.

1078
00:49:31,465 --> 00:49:33,940
Ara inti mbagħad.

1079
00:49:33,940 --> 00:49:37,880
>> Narrator: Fil-CS50 jmiss, Rob
taġġusta li jkunu barra mill-

1080
00:49:37,880 --> 00:49:39,130
Harvard pjan ta 'ikla.

1081
00:49:39,130 --> 00:49:56,160