1
00:00:00,000 --> 00:00:10,970
>> [Halisi kucheza]

2
00:00:10,970 --> 00:00:12,536
>> DAVID J. Malan: zote haki.

3
00:00:12,536 --> 00:00:13,392
>> [Kicheko]

4
00:00:13,392 --> 00:00:14,240
>> Karibu tena.

5
00:00:14,240 --> 00:00:14,990
Hii ni CS50.

6
00:00:14,990 --> 00:00:16,890
Na hii ya mwisho wa wiki tano.

7
00:00:16,890 --> 00:00:20,020
Na hadi sasa, tumekuwa pretty much
imekuwa kuchukua nafasi ya kwamba kuna

8
00:00:20,020 --> 00:00:23,480
ipo hii mkusanyaji, Clang, kwamba wewe wameweza
wamekuwa kutaja kwa njia ya hii

9
00:00:23,480 --> 00:00:27,100
chombo nyingine iitwayo kufanya kwamba kwa namna fulani
magically waongofu chanzo yako kificho

10
00:00:27,100 --> 00:00:31,350
katika kitu kificho, zeros na ndio
kwamba yako kompyuta CPU, kati

11
00:00:31,350 --> 00:00:33,410
usindikaji kitengo, kweli anaelewa.

12
00:00:33,410 --> 00:00:36,770
Lakini zinageuka kuna idadi hiyo ni
kinachoendelea chini ya Hood katika

13
00:00:36,770 --> 00:00:38,690
kati ya pembejeo na mazao.

14
00:00:38,690 --> 00:00:41,800
>> Na ningependa kupendekeza kwamba sisi mwili
kuwa nje kwa undani zaidi kidogo katika

15
00:00:41,800 --> 00:00:45,130
hatua hizi nne, kuwa na kitu kinachoitwa
kabla ya usindikaji, kitu

16
00:00:45,130 --> 00:00:48,300
kuitwa kuandaa, ambayo tumeona,
kitu kinachoitwa kukusanyika, na

17
00:00:48,300 --> 00:00:49,420
kitu kinachoitwa kuunganisha.

18
00:00:49,420 --> 00:00:53,270
Hivyo hadi sasa, katika baadhi ya yetu ya
mipango, tumekuwa alikuwa mkali pamoja.

19
00:00:53,270 --> 00:00:56,650
Hivi karibuni tulikuwa na baadhi mkali
amefafanua kwa constants.

20
00:00:56,650 --> 00:01:00,660
Hivyo zinageuka kuwa yale mambo
ni prefixed na alama hash au

21
00:01:00,660 --> 00:01:04,150
alama ya pound ni kabla ya processor
maelekezo.

22
00:01:04,150 --> 00:01:07,960
Hiyo ni njia tu ya dhana ya kusema ni
mstari wa kanuni kwamba ni kweli

23
00:01:07,960 --> 00:01:12,280
waongofu katika kitu kingine kabla ya
kompyuta hata kujaribu kubadili yako

24
00:01:12,280 --> 00:01:13,800
mpango katika zeros na ndio.

25
00:01:13,800 --> 00:01:19,000
>> Kwa mfano, kali ni pamoja na kiwango
I / O h., Pretty much tu ina maana kwenda

26
00:01:19,000 --> 00:01:24,010
mbele, kunyakua yaliyomo ya mafaili
stdio.h na kuweka haki yao huko.

27
00:01:24,010 --> 00:01:25,880
Hivyo hakuna zeros na ndio
katika hatua bado.

28
00:01:25,880 --> 00:01:27,470
Ni kweli tu badala.

29
00:01:27,470 --> 00:01:30,790
Na kwamba kufanyika wakati kinachojulikana
kabla ya usindikaji hatua, wakati wewe

30
00:01:30,790 --> 00:01:34,230
kweli kuendesha Clang au hasa
Kufanya katika kesi nyingi.

31
00:01:34,230 --> 00:01:36,950
Hivyo wote hii imekuwa ikitokea
kwanza moja kwa moja hivi sasa.

32
00:01:36,950 --> 00:01:38,800
>> Kisha huja hatua mkusanyiko.

33
00:01:38,800 --> 00:01:40,920
Lakini sisi tumekuwa oversimplified
mkusanyiko.

34
00:01:40,920 --> 00:01:45,060
Kuandaa mpango wa kweli maana ya
kuchukua kutoka kitu kama C,

35
00:01:45,060 --> 00:01:48,430
chanzo kanuni tumekuwa kuandika, chini
kwa kitu kinachoitwa mkutano.

36
00:01:48,430 --> 00:01:52,900
Bunge lugha ni ngazi ya chini
lugha hiyo, nashiriki, sisi si

37
00:01:52,900 --> 00:01:55,480
kuwa mengi tukio
kuandika hii muhula.

38
00:01:55,480 --> 00:01:59,100
Lakini ni katika ngazi ya chini kabisa katika
maana ya kwamba wewe literally kuanza kuandika

39
00:01:59,100 --> 00:02:04,270
kutoa na kujumlisha na kuzidisha na mzigo
kutokana na kumbukumbu na kuokoa na kumbukumbu,

40
00:02:04,270 --> 00:02:08,259
msingi sana maelekezo ya kwamba kompyuta,
chini ya Hood,

41
00:02:08,259 --> 00:02:09,639
kweli anaelewa.

42
00:02:09,639 --> 00:02:14,930
>> Mwisho, kukusanyika inachukua kwamba lugha
kwa zeros na wale ambao tumekuwa

43
00:02:14,930 --> 00:02:16,190
kuelezea hivi sasa.

44
00:02:16,190 --> 00:02:19,270
Na kweli mwishowe, kuna kinachojulikana
kuunganisha awamu, ambayo tutaweza

45
00:02:19,270 --> 00:02:22,360
kuona katika wakati huu tu, ambao unachanganya
zeros yako na ndio na zeros na

46
00:02:22,360 --> 00:02:24,870
wale watu wengine kabla ya
una umba.

47
00:02:24,870 --> 00:02:26,660
>> Hivyo kufikiria hili super rahisi mpango.

48
00:02:26,660 --> 00:02:27,560
Ni kutokana na Wiki 1.

49
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Ni tu alisema, Hello Dunia,
kwenye screen.

50
00:02:29,610 --> 00:02:30,920
Sisi mbio hili kwa njia ya Clang.

51
00:02:30,920 --> 00:02:33,200
Au sisi mbio ni kwa njia ya kufanya
ambayo mbio Clang.

52
00:02:33,200 --> 00:02:36,170
Na outputted wakati ambapo
baadhi zeros na ndio.

53
00:02:36,170 --> 00:02:38,100
Lakini zinageuka kuna
hatua ya kati.

54
00:02:38,100 --> 00:02:40,460
Kama mimi kwenda juu hapa - oops, hakuwa
wanataka kumwona bado.

55
00:02:40,460 --> 00:02:44,800
Kama mimi kwenda juu hapa appliance yangu
na mimi kufungua hello.c, hapa

56
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ni kwamba mpango huo.

57
00:02:46,160 --> 00:02:48,600
Na kile Mimi naenda kufanya katika terminal yangu
dirisha hapa ni mimi nina kwenda

58
00:02:48,600 --> 00:02:51,430
kukimbia Clang badala ya kufanya, ambayo
automates zote nne za

59
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wale hatua kwa ajili yetu.

60
00:02:52,870 --> 00:02:58,620
Na mimi naenda kufanya Clang-S na
kisha hello.c na kisha kuingia.

61
00:02:58,620 --> 00:03:00,590
>> Na mimi kupata haraka blinking
tena, ambayo ni nzuri.

62
00:03:00,590 --> 00:03:05,280
Na sasa katika dirisha kubwa kidogo,
Mimi naenda kufungua gedit katika hapa.

63
00:03:05,280 --> 00:03:09,610
Na mimi nina kwenda kufungua faili kwamba,
zamu nje, ni kuitwa hello.s hii

64
00:03:09,610 --> 00:03:11,870
lina lugha ya mkutano
Mimi inajulikana mapema.

65
00:03:11,870 --> 00:03:15,060
Na hii ni nini wito mkutano
lugha, haki ya chini ngazi

66
00:03:15,060 --> 00:03:18,470
maelekezo ya kwamba yako Intel CPU
au chochote ni kwamba ndani ya

67
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anaelewa.

68
00:03:19,350 --> 00:03:24,480
Na MOV ni kwa hoja. simu ni kwa
wito, chini sana ngazi ya kazi.

69
00:03:24,480 --> 00:03:26,380
ndogo ni kwa ajili ya Ondoa.

70
00:03:26,380 --> 00:03:30,370
>> Hivyo wakati una CPU hasa ndani ya
ya kompyuta yako, nini inafanya

71
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tofauti, dhidi ya nyingine CPUs juu ya
soko, ni maelekezo ambayo ni

72
00:03:34,300 --> 00:03:39,460
anaelewa na mara nyingi jinsi ufanisi ni
ni, jinsi ya kufunga ni katika utekelezaji wa baadhi ya

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00:03:39,460 --> 00:03:40,380
ya wale maelekezo.

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00:03:40,380 --> 00:03:45,150
Sasa kwa zaidi juu ya hili, unaweza kuchukua
ijayo Fall CS61 chuoni.

75
00:03:45,150 --> 00:03:48,170
Lakini hapa tuna, kwa mfano, wachache
vitambulisho kwamba ili kuangalia ukoo.

76
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hello.c ni jina la mpango.

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>> . Asilia -

78
00:03:51,070 --> 00:03:54,190
kuna si mengi ya riba kuna
tu sasa, kukumbuka kwamba maandishi

79
00:03:54,190 --> 00:03:59,190
sehemu, kama ya Jumatatu, ni wapi katika
kumbukumbu ya mpango wako kwa kweli mwisho juu.

80
00:03:59,190 --> 00:04:01,330
Hivyo kwamba ni angalau bila kufafanua
ukoo huko.

81
00:04:01,330 --> 00:04:03,730
Hapa, bila shaka, ni kutaja
ya kazi yetu kuu.

82
00:04:03,730 --> 00:04:07,220
Scrolling chini, hizi kutaja mambo
kinachoitwa madaftari, ndogo sana chunks ya

83
00:04:07,220 --> 00:04:09,190
kumbukumbu ndani ya CPU yako halisi.

84
00:04:09,190 --> 00:04:12,930
Na kama mimi kitabu chini hata
zaidi, mimi kuona baadhi ya aina

85
00:04:12,930 --> 00:04:14,240
moja kwa moja kutaja ya ASCII.

86
00:04:14,240 --> 00:04:17,120
Na pale, kwa kweli, ni kamba kwamba,
hello, comma, dunia.

87
00:04:17,120 --> 00:04:20,079
>> Hivyo muda mrefu hadithi fupi, hii imekuwa
kinachotokea kwa ajili yenu, moja kwa moja,

88
00:04:20,079 --> 00:04:22,140
chini ya Hood yote ya wakati huu.

89
00:04:22,140 --> 00:04:26,450
Na kinachotokea kwa kweli ni mara moja
umefanya kukimbia Clang, au kwa njia ya

90
00:04:26,450 --> 00:04:29,150
Kufanya, wewe ni kupata ya kwanza,
kutoka chanzo code,

91
00:04:29,150 --> 00:04:30,700
kinachojulikana mkutano wa lugha.

92
00:04:30,700 --> 00:04:35,210
Kisha Clang ni kuwabadili kusanyiko hili
Lugha chini zeros na ndio.

93
00:04:35,210 --> 00:04:38,340
Na hii ni slide kwamba sisi ilianza
mjadala wetu katika Wiki 0 juu -

94
00:04:38,340 --> 00:04:39,840
na kisha Wiki 1 juu.

95
00:04:39,840 --> 00:04:44,030
Na kisha hatimaye, wale zeros na ndio
ni pamoja na zeros na ndio

96
00:04:44,030 --> 00:04:47,190
kutoka maktaba wale tumekuwa kuchukua
kwa nafasi kama darasa la I / O au

97
00:04:47,190 --> 00:04:50,010
Kamba Library au hata
Maktaba CS50.

98
00:04:50,010 --> 00:04:54,200
>> Hivyo kwa rangi hii picha zaidi
kuibua, tuna hello.c.

99
00:04:54,200 --> 00:04:57,220
Na, bila shaka, anatumia printf
kazi ya kusema, hello dunia.

100
00:04:57,220 --> 00:05:01,810
hatua ya mkusanyiko inachukua ni chini ya
kwamba faili sisi tu kuona hello.s, hata

101
00:05:01,810 --> 00:05:04,290
ingawa hiyo ni kawaida ilifutwa
moja kwa moja kwa ajili yenu.

102
00:05:04,290 --> 00:05:06,050
Lakini hiyo ni kanuni ya kanisa
katika hatua ya katikati.

103
00:05:06,050 --> 00:05:09,750
Na wakati sisi kukusanyika mkutano
lugha, hivyo kusema, kwamba wakati wewe

104
00:05:09,750 --> 00:05:10,830
kupata zeros hizo na zile.

105
00:05:10,830 --> 00:05:13,920
Hivyo tumekuwa zoomed katika ufanisi leo juu ya
nini tumekuwa kuchukua kwa nafasi,

106
00:05:13,920 --> 00:05:16,430
ina maana ya kwenda chanzo kanuni
ya kupinga kanuni.

107
00:05:16,430 --> 00:05:18,850
>> Lakini mwishowe, sasa kwamba picha hiyo -
hebu shove ni juu ya

108
00:05:18,850 --> 00:05:20,020
mkono wa kushoto upande.

109
00:05:20,020 --> 00:05:22,880
Na kutambua kwamba katika juu kuna
Nilivyoeleza stdio.h.

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00:05:22,880 --> 00:05:25,030
Hiyo ni faili kwamba tumekuwa pamoja
katika karibu wote wa

111
00:05:25,030 --> 00:05:26,250
mipango tumekuwa imeandikwa.

112
00:05:26,250 --> 00:05:28,830
Na kwamba faili ambaye yaliyomo
kupata nakala pasted,

113
00:05:28,830 --> 00:05:30,350
ufanisi atop code yako.

114
00:05:30,350 --> 00:05:34,170
Lakini zinageuka kuwa, kwenye kompyuta
mfumo mahali fulani, kuna labda

115
00:05:34,170 --> 00:05:39,150
stdio.c faili kwamba mtu aliandika miaka
iliyopita kwamba zana zote za

116
00:05:39,150 --> 00:05:41,870
kazi ambayo yalitangazwa
katika stdio.h.

117
00:05:41,870 --> 00:05:45,465
>> Sasa katika hali halisi ni pengine si juu ya
Mac au PC yako au hata katika

118
00:05:45,465 --> 00:05:47,660
CS50 appliance ni mbichi C kanuni.

119
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Mtu tayari ulioandaliwa ni pamoja na
. O faili kwa ajili ya kitu au kanuni.

120
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faili, ambayo inahusu maktaba pamoja
kwamba imekuwa kabla ya imewekwa na

121
00:05:56,020 --> 00:05:57,240
kabla ya ulioandaliwa kwa ajili yenu.

122
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Lakini tuseme kwamba kuna kweli ipo
kwenye kompyuta yetu stdio.c sambamba

123
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na Clang.

124
00:06:02,650 --> 00:06:04,960
Kificho wako wa kuwa compiled
na wamekusanyika.

125
00:06:04,960 --> 00:06:09,200
kanuni stdio.c 's ni kuwa ulioandaliwa na
wamekusanyika, kwa hivyo hili sana mwisho

126
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hatua, hapa chini, inabidi kwa namna fulani
kiungo, hivyo kusema, zeros yako na wale

127
00:06:13,730 --> 00:06:18,430
na yake zeros na ndio katika moja
rahisi mpango ni kwamba hatimaye

128
00:06:18,430 --> 00:06:20,540
kuitwa tu Hello.

129
00:06:20,540 --> 00:06:23,340
>> Hivyo hiyo yote ya uchawi kwamba ni
yakitokea hivi sasa.

130
00:06:23,340 --> 00:06:26,430
Na itaendelea kuchukua hizi
michakato kwa nafasi, lakini kutambua

131
00:06:26,430 --> 00:06:28,750
kuna mengi ya maelezo Juicy
kinachoendelea chini ya hapo.

132
00:06:28,750 --> 00:06:31,920
Na hii ni nini hufanya yako
kompyuta na Intel ndani

133
00:06:31,920 --> 00:06:33,940
hasa tofauti.

134
00:06:33,940 --> 00:06:37,020
>> Kadhalika kumbuka kwamba, kama ungependa
kujiunga na sisi kwa chakula cha mchana Ijumaa hii, kufanya kwenda

135
00:06:37,020 --> 00:06:41,570
kwa cs50.net/rsvp kawaida mahali,
1:15 Ijumaa hii.

136
00:06:41,570 --> 00:06:43,400
Na sasa matangazo machache.

137
00:06:43,400 --> 00:06:44,670
Hivyo tuna baadhi ya habari njema.

138
00:06:44,670 --> 00:06:45,970
Na tuna baadhi ya habari mbaya.

139
00:06:45,970 --> 00:06:47,260
Kuanza na baadhi ya habari nzuri hapa.

140
00:06:47,260 --> 00:06:52,038

141
00:06:52,038 --> 00:06:54,510
>> [Kuugua]

142
00:06:54,510 --> 00:06:54,710
>> Wote haki.

143
00:06:54,710 --> 00:06:56,670
Naam, ni kitaalam likizo, hivyo
siyo sana zawadi kutoka kwetu.

144
00:06:56,670 --> 00:06:58,030
Lakini basi habari mbaya ya shaka.

145
00:06:58,030 --> 00:07:00,550

146
00:07:00,550 --> 00:07:01,880
>> [Kuugua]

147
00:07:01,880 --> 00:07:03,530
>> Mimi alitumia muda mwingi
juu ya haya michoro.

148
00:07:03,530 --> 00:07:04,690
>> [Kicheko]

149
00:07:04,690 --> 00:07:07,000
>> Kutakuwa na kikao cha mapitio
hii Jumatatu ijayo.

150
00:07:07,000 --> 00:07:08,340
Ni kwenda kuwa, saa 05:30.

151
00:07:08,340 --> 00:07:11,210
Sisi kuwakumbusha hayo maelezo yote
kupitia barua pepe juu ya kozi

152
00:07:11,210 --> 00:07:13,470
tovuti katika michache tu ya muda siku.

153
00:07:13,470 --> 00:07:16,610
Itakuwa zingine na kufanywa kupatikana
baada ya muda mfupi.

154
00:07:16,610 --> 00:07:19,200
Hivyo kama huwezi kufanya kwamba Jumatatu
usiku yanayopangwa, msiwe na wasiwasi.

155
00:07:19,200 --> 00:07:22,270
Sehemu hii wiki ijayo mapenzi pia
kuzingatia marekebisho kwa jaribio.

156
00:07:22,270 --> 00:07:25,670
Kama sehemu yako ni siku ya Jumatatu, ambayo ni
kweli chuo kikuu likizo, sisi

157
00:07:25,670 --> 00:07:26,920
bado kukutana katika sehemu.

158
00:07:26,920 --> 00:07:28,890
Kama wewe tu hawezi kufanya kwamba
sehemu kwa sababu wewe ni kwenda

159
00:07:28,890 --> 00:07:29,860
mbali, hiyo faini.

160
00:07:29,860 --> 00:07:33,710
Kuhudhuria Jumapili au Jumanne sehemu au
tune-katika sehemu Jason, ambayo ni

161
00:07:33,710 --> 00:07:35,110
inapatikana online.

162
00:07:35,110 --> 00:07:37,490
>> Hivyo, zaidi ya habari mbaya.

163
00:07:37,490 --> 00:07:41,960
Hivyo kulingana na mtaala,
tuna hotuba Ijumaa ijayo.

164
00:07:41,960 --> 00:07:43,690
Lakini habari njema -

165
00:07:43,690 --> 00:07:44,860
uwazi, Mimi alitumia muda mwingi sana juu ya hili.

166
00:07:44,860 --> 00:07:45,280
>> [Kicheko]

167
00:07:45,280 --> 00:07:47,140
>> Tutaweza kufuta ijayo mihadhara ya Ijumaa.

168
00:07:47,140 --> 00:07:50,590
Hivyo kwamba itakuwa zawadi kwa ajili yetu, hivyo
unaweza kweli kuwa nzuri katika muhula

169
00:07:50,590 --> 00:07:52,990
kati ya wiki hii na wiki mbili hapa.

170
00:07:52,990 --> 00:07:57,460
Hivyo hakuna mihadhara wiki ijayo, tu vidogo
Jaribio kidogo, ambayo unapaswa kuwa

171
00:07:57,460 --> 00:07:59,030
kupata inazidi msisimko.

172
00:07:59,030 --> 00:08:03,870
>> Basi hebu sasa kurejea mawazo yetu kwa
kitu ambacho kwa kweli ni zaidi ya Visual

173
00:08:03,870 --> 00:08:06,990
na zaidi ya kusisimua na kuweka hatua
kwa ajili ya nini kinaendelea kuwa kwenye upeo wa macho

174
00:08:06,990 --> 00:08:08,420
katika michache tu ya muda wa wiki.

175
00:08:08,420 --> 00:08:12,160
Baada ya jaribio la kwanza, tutaweza kugeuka
lengo la tatizo letu seti mwingine

176
00:08:12,160 --> 00:08:16,710
domain maalum tatizo, ile ya
forensics au usalama zaidi kwa ujumla.

177
00:08:16,710 --> 00:08:19,550
>> Kwa kweli, mila na tatizo hili
kuweka ni kwa ajili yangu moja ya

178
00:08:19,550 --> 00:08:24,850
kufundisha wenzao au CAS kutembea katika
chuo kuchukua picha ya baadhi ya

179
00:08:24,850 --> 00:08:29,450
zinazotambulika lakini si dhahiri watu,
maeneo, au vitu, kisha kila mwaka mimi

180
00:08:29,450 --> 00:08:34,520
namna fulani kusimamia na ajali kufuta
au kuharibu kadi digital vyombo vya habari

181
00:08:34,520 --> 00:08:35,720
kwamba ndani ya kamera yetu.

182
00:08:35,720 --> 00:08:36,860
Lakini hakuna mpango mkubwa.

183
00:08:36,860 --> 00:08:39,200
Siwezi kwenda mbele na kuziba
kwamba katika kompyuta yangu.

184
00:08:39,200 --> 00:08:43,010
Siwezi kufanya sanamu ya kuchunguza mauaji ya hivyo, hivyo
kusema, kwa kuiga zeros na

185
00:08:43,010 --> 00:08:46,830
ndio mbali ya kadi ya kwamba kumbukumbu, kama
yake ya kadi ya SD au au kadi Compact flash

186
00:08:46,830 --> 00:08:48,100
chochote wewe ni ukoo na.

187
00:08:48,100 --> 00:08:49,300
Na kisha tunaweza mkono kwamba nje.

188
00:08:49,300 --> 00:08:53,190
>> Na hivyo changamoto mbele, kati ya mengine
mambo kwa ajili yenu, itakuwa kuandika

189
00:08:53,190 --> 00:08:58,630
C kificho kwamba recovers rundo zima la
JPEGs kwa ajili yangu na umebaini kuwa

190
00:08:58,630 --> 00:09:00,190
wale watu, mahali, au mambo.

191
00:09:00,190 --> 00:09:03,340
Na tutaweza pia kuzungumza, katika tatizo hili
kuweka na katika siku zijazo, kuhusu

192
00:09:03,340 --> 00:09:04,440
graphics zaidi kwa ujumla.

193
00:09:04,440 --> 00:09:06,140
Tumekuwa kutumika kwao, bila shaka,
kwa kuvunja nje.

194
00:09:06,140 --> 00:09:09,080
Lakini umefanya aina ya kuchukuliwa kwa nafasi
kuna hizi ngazi ya juu fikra

195
00:09:09,080 --> 00:09:10,680
ya mistatili na ovals.

196
00:09:10,680 --> 00:09:12,450
Lakini chini ya Hood
kuna saizi.

197
00:09:12,450 --> 00:09:14,370
Na wewe alikuwa na kuanza
kufikiri juu ya hayo.

198
00:09:14,370 --> 00:09:18,800
Au wewe kwa ajili ya p-seti 4 na kufikiri
kuhusu pengo kati ya matofali yako, jinsi

199
00:09:18,800 --> 00:09:21,990
haraka wewe ni mpira ni kusonga hela
screen kwa kuvunja nje.

200
00:09:21,990 --> 00:09:24,830
Hivyo kuna wazo hili la
dots juu ya screen yako kwamba ni

201
00:09:24,830 --> 00:09:26,290
kuja kucheza tayari.

202
00:09:26,290 --> 00:09:29,430
>> Sasa nini kuona, ingawa, ni nini
kupata kwenye screen ya kompyuta.

203
00:09:29,430 --> 00:09:33,680
Kama ve milele watched baadhi nzuri au
TV mbaya, ni tabia mbaya wao pretty much

204
00:09:33,680 --> 00:09:36,280
kutibu watazamaji kama technophobes
ambao si kweli

205
00:09:36,280 --> 00:09:37,630
kujua mengi kuhusu kompyuta.

206
00:09:37,630 --> 00:09:40,840
Na hivyo ni rahisi sana kwa ajili ya polisi
upelelezi kusema, unaweza

207
00:09:40,840 --> 00:09:41,710
safi kuwa hadi kwa ajili yangu?

208
00:09:41,710 --> 00:09:42,710
Au kuboresha, haki?

209
00:09:42,710 --> 00:09:45,550
Kuongeza ni kama neno buzz katika
yoyote zaidi uhalifu kuhusiana show.

210
00:09:45,550 --> 00:09:49,240
Na ukweli ni kama kuchukua sana
blurry picha ya mtuhumiwa kufanya

211
00:09:49,240 --> 00:09:51,620
kitu mbaya, huwezi
tu kuongeza yake.

212
00:09:51,620 --> 00:09:53,080
Huwezi kuvuta kubwa.

213
00:09:53,080 --> 00:09:56,350
Huwezi kuona katika glint ya mtu
jicho waliofanya kwamba

214
00:09:56,350 --> 00:09:59,860
hasa uhalifu, licha ya
maambukizi ya hii kwenye TV.

215
00:09:59,860 --> 00:10:04,110
>> Na hivyo na kwamba hebu kuwahamasisha kwamba
tatizo ujao kuweka na mtazamo saa

216
00:10:04,110 --> 00:10:05,765
baadhi inaonyesha na ambayo
wapate kuwa ukoo.

217
00:10:05,765 --> 00:10:06,500
>> [Video avspelning]

218
00:10:06,500 --> 00:10:07,835
>> -OK.

219
00:10:07,835 --> 00:10:09,956
Sasa, hebu kupata nzuri kuangalia wewe.

220
00:10:09,956 --> 00:10:17,060

221
00:10:17,060 --> 00:10:17,766
>> -Hold yake.

222
00:10:17,766 --> 00:10:18,658
Kukimbia kwamba nyuma.

223
00:10:18,658 --> 00:10:19,550
>> -Subiri dakika.

224
00:10:19,550 --> 00:10:21,580
Kwenda kulia.

225
00:10:21,580 --> 00:10:21,800
>> -Kuna.

226
00:10:21,800 --> 00:10:22,690
Kufungia kwamba.

227
00:10:22,690 --> 00:10:23,692
>> -Full screen.

228
00:10:23,692 --> 00:10:23,846
>> -OK.

229
00:10:23,846 --> 00:10:24,154
Kufungia kwamba.

230
00:10:24,154 --> 00:10:25,140
>> -Kaza juu ya kwamba, mapenzi ya?

231
00:10:25,140 --> 00:10:27,090
>> -Vector katika juu ya guy kwamba
na gurudumu nyuma.

232
00:10:27,090 --> 00:10:29,730
>> -Zoom katika haki hapa kwenye doa hili.

233
00:10:29,730 --> 00:10:33,700
>> -Pamoja na vifaa vya kulia, imaged
unaweza kuwa wazi kabisa na makali.

234
00:10:33,700 --> 00:10:34,490
>> -Ni nini hiyo?

235
00:10:34,490 --> 00:10:35,870
>> -Ni mpango kukuza.

236
00:10:35,870 --> 00:10:36,793
>> -Je, unaweza wazi kuwa hadi yoyote?

237
00:10:36,793 --> 00:10:38,560
>> -Mimi sijui.

238
00:10:38,560 --> 00:10:39,090
Hebu kuongeza yake.

239
00:10:39,090 --> 00:10:41,690
>> -Kuongeza kifungu-6.

240
00:10:41,690 --> 00:10:43,510
>> -I kuimarishwa undani na -

241
00:10:43,510 --> 00:10:44,456
>> -Nadhani kuna kutosha kuimarisha.

242
00:10:44,456 --> 00:10:45,402
Kutolewa kwa screen yangu.

243
00:10:45,402 --> 00:10:47,300
>> -Kuongeza kutafakari katika macho yake.

244
00:10:47,300 --> 00:10:49,330
>> -Hebu kukimbia hii kupitia
video kukuza.

245
00:10:49,330 --> 00:10:50,340
>> -Edgar, unaweza kuongeza hii?

246
00:10:50,340 --> 00:10:52,320
>> -Hutegemea.

247
00:10:52,320 --> 00:10:54,290
>> -I've been kazi tafakari hii.

248
00:10:54,290 --> 00:10:55,560
>> -Mtu wa kutafakari.

249
00:10:55,560 --> 00:10:56,440
>> -Reflection.

250
00:10:56,440 --> 00:10:57,940
>> -Kuna tafakari
ya uso wa mtu.

251
00:10:57,940 --> 00:10:58,860
>> -Kutafakari.

252
00:10:58,860 --> 00:10:59,710
>> -Kuna kutafakari.

253
00:10:59,710 --> 00:11:00,900
>> -Zoom katika juu ya kioo.

254
00:11:00,900 --> 00:11:03,500
>> -Unaweza kuona kutafakari.

255
00:11:03,500 --> 00:11:04,700
>> -Je, unaweza kuongeza picha kutoka hapa?

256
00:11:04,700 --> 00:11:05,700
>> -Je, unaweza kuimarisha haki yake hapa?

257
00:11:05,700 --> 00:11:06,500
>> -Je, unaweza kuongeza yake?

258
00:11:06,500 --> 00:11:07,380
>> -Je, unaweza kuongeza yake?

259
00:11:07,380 --> 00:11:08,190
>> -Je, tunaweza kuongeza hii?

260
00:11:08,190 --> 00:11:08,940
>> -Je, unaweza kuongeza yake?

261
00:11:08,940 --> 00:11:10,280
>> -Kushikilia pili, mimi itabidi kuongeza.

262
00:11:10,280 --> 00:11:11,570
>> -Zoom katika juu ya mlango.

263
00:11:11,570 --> 00:11:12,180
>> -X10.

264
00:11:12,180 --> 00:11:13,052
>> -Zoom.

265
00:11:13,052 --> 00:11:13,197
>> [Kicheko]

266
00:11:13,197 --> 00:11:14,360
>> Hoja-in

267
00:11:14,360 --> 00:11:15,100
>> -Subiri, kuacha.

268
00:11:15,100 --> 00:11:15,740
>> -Stop.

269
00:11:15,740 --> 00:11:16,290
>> -Pause yake.

270
00:11:16,290 --> 00:11:19,390
>> -Mzunguko digrii 75 kote
wima tafadhali.

271
00:11:19,390 --> 00:11:19,886
>> [Kicheko]

272
00:11:19,886 --> 00:11:24,350
>> -Stop, na nyuma ya sehemu
kuhusu mlango tena.

273
00:11:24,350 --> 00:11:26,330
>> -Got enhancer picha
kwamba unaweza bitmap?

274
00:11:26,330 --> 00:11:28,990
>> -Labda tunaweza kutumia Sen Pradeep
njia ya kuona katika madirisha.

275
00:11:28,990 --> 00:11:30,680
>> -Hii ni programu ya hali ya sanaa.

276
00:11:30,680 --> 00:11:31,676
>> Za thamani ya icon ni mbali.

277
00:11:31,676 --> 00:11:34,166
>> -Na macho haki
ya algorithms.

278
00:11:34,166 --> 00:11:38,399
>> -Yeye kuchukuliwa algorithms kuja kwa
ngazi ya pili na mimi unaweza kuzitumia ili

279
00:11:38,399 --> 00:11:38,648
kuongeza hii picha.

280
00:11:38,648 --> 00:11:42,050
>> -Lock juu na kupanua z-mhimili.

281
00:11:42,050 --> 00:11:42,760
>> -Kuongeza.

282
00:11:42,760 --> 00:11:43,060
>> -Kuongeza.

283
00:11:43,060 --> 00:11:43,760
>> -Kuongeza.

284
00:11:43,760 --> 00:11:45,010
>> -Freeze na kuongeza.

285
00:11:45,010 --> 00:11:47,470

286
00:11:47,470 --> 00:11:47,910
>> [MWISHO video avspelning]

287
00:11:47,910 --> 00:11:51,470
>> DAVID J. Malan: Hivyo Tatizo Set
5 ni kile uongo mbele huko.

288
00:11:51,470 --> 00:11:55,260
Hivyo tutaweza karibuni kupata uelewa bora
ya wakati na kwa nini unaweza

289
00:11:55,260 --> 00:11:57,300
na yetu haiwezi kuongeza katika njia hiyo.

290
00:11:57,300 --> 00:12:00,090
Lakini kwanza, hebu kurudi tahadhari yetu
kwa baadhi ya vitalu jengo tutaweza

291
00:12:00,090 --> 00:12:02,250
haja ya kuwa na uwezo wa kuwaambia kwamba hadithi.

292
00:12:02,250 --> 00:12:05,580
>> Hivyo kukumbuka kuwa sisi akauchomoa hii picha kwenye
Jumatatu na kidogo wiki iliyopita.

293
00:12:05,580 --> 00:12:09,970
Na hii inaelezea mpangilio wa mambo
katika kumbukumbu ya kompyuta yako wakati

294
00:12:09,970 --> 00:12:11,000
mbio baadhi mpango.

295
00:12:11,000 --> 00:12:14,310
sehemu tech juu juu, kukumbuka, inahusu
kwa zeros halisi na ndio

296
00:12:14,310 --> 00:12:16,000
ambayo kutunga programu yako.

297
00:12:16,000 --> 00:12:19,340
Kuna, chini ya kwamba, au baadhi ya initialized
uninitialized data, ambayo kwa kawaida

298
00:12:19,340 --> 00:12:22,910
inahusu mambo kama constants au
masharti au vigezo kimataifa kwamba kuwa

299
00:12:22,910 --> 00:12:24,200
imetangazwa mapema.

300
00:12:24,200 --> 00:12:26,500
Kuna lundo, lakini tutaweza kuja
nyuma na kwamba katika kidogo.

301
00:12:26,500 --> 00:12:27,410
>> Na kisha kuna stack.

302
00:12:27,410 --> 00:12:30,660
Kiasi kama mkusanyiko wa sania katika
mkahawa, hii ni wapi anapata kumbukumbu

303
00:12:30,660 --> 00:12:33,610
layered na layered wakati wowote
kufanya nini katika mpango?

304
00:12:33,610 --> 00:12:36,380

305
00:12:36,380 --> 00:12:37,730
Kile ni matumizi stack kwa?

306
00:12:37,730 --> 00:12:39,320
>> Yeah?

307
00:12:39,320 --> 00:12:40,000
>> Wito wa kazi.

308
00:12:40,000 --> 00:12:42,890
Wakati wowote wewe piga kazi, ni
aliyopewa Sliver ya kumbukumbu kwa ajili ya wake

309
00:12:42,890 --> 00:12:45,020
mitaa vigezo au vigezo wake.

310
00:12:45,020 --> 00:12:48,810
Na pictorially, tunaona kwamba kwa kila
kazi mfululizo kuitwa, wakati

311
00:12:48,810 --> 00:12:52,520
B C wito wito wito D, wao
kupata layered kwenye stack.

312
00:12:52,520 --> 00:12:55,630
Na ndani ya kila moja ya vipande wale wa
kumbukumbu kimsingi ni upeo wa kipekee

313
00:12:55,630 --> 00:12:58,590
kwa ajili ya kazi kwamba, ambayo, bila shaka,
ni tatizo kama unataka mkono

314
00:12:58,590 --> 00:13:01,850
kutokana na kazi moja hadi nyingine kipande
ya data kwamba unataka

315
00:13:01,850 --> 00:13:03,500
mutate au kubadilika.

316
00:13:03,500 --> 00:13:08,060
>> Hivyo kile alikuwa ufumbuzi wetu kuwezesha
kazi kuwakilishwa na stack moja

317
00:13:08,060 --> 00:13:11,390
sura na mabadiliko ndani ya kumbukumbu
wa mwingine sura ya stack?

318
00:13:11,390 --> 00:13:14,590
Jinsi ya kufanya wale majadiliano 12:58 mwingine?

319
00:13:14,590 --> 00:13:18,510
Hivyo kwa njia ya kuyatumia au anwani,
ambayo, tena, tu kuelezea ambapo katika

320
00:13:18,510 --> 00:13:22,280
kumbukumbu, kwa njia ya maalum
bite ya simu, hasa

321
00:13:22,280 --> 00:13:23,830
thamani inaweza kupatikana.

322
00:13:23,830 --> 00:13:26,860
Hivyo kukumbuka mara ya mwisho pia tuliendelea
hadithi na inaonekana katika

323
00:13:26,860 --> 00:13:28,280
haki Buggy mpango.

324
00:13:28,280 --> 00:13:32,900
Na mpango huu ni Buggy kwa ajili ya wachache
sababu, lakini inatia mashaka ni moja ya

325
00:13:32,900 --> 00:13:34,620
kwa sababu inashindwa kuangalia nini?

326
00:13:34,620 --> 00:13:39,111

327
00:13:39,111 --> 00:13:40,450
>> Yeah, inashindwa kuangalia pembejeo.

328
00:13:40,450 --> 00:13:41,870
Pole?

329
00:13:41,870 --> 00:13:43,880
>> Kama ni zaidi ya wahusika 12.

330
00:13:43,880 --> 00:13:47,260
Sana smartly, wakati wito memcopy,
ambayo, kama jina linavyosema, tu

331
00:13:47,260 --> 00:13:50,630
nakala ya kumbukumbu kutoka hoja yake ya pili
katika hoja yake ya kwanza.

332
00:13:50,630 --> 00:13:54,730
Hoja ya tatu, sana smartly, ni
checked kuhakikisha kwamba huna

333
00:13:54,730 --> 00:13:59,400
nakala zaidi, katika kesi hii, urefu
ya bar, idadi ya wahusika,

334
00:13:59,400 --> 00:14:03,810
ndani ya marudio, ambayo ni hii
safu C. Lakini tatizo ni kwamba kile

335
00:14:03,810 --> 00:14:07,230
ikiwa C yenyewe si kubwa ya kutosha
kushughulikia kwamba?

336
00:14:07,230 --> 00:14:09,900
Wewe ni kwenda na nakala ya simu ya
ka kwamba tumekuwa aliyopewa.

337
00:14:09,900 --> 00:14:13,040
Lakini je, kweli kuwa zaidi
ka kuliko wewe kuwa na chumba kwa ajili ya?

338
00:14:13,040 --> 00:14:16,770
>> Naam, hii mpango upumbavu tu
upofu kuendelea na kuchukua chochote ni

339
00:14:16,770 --> 00:14:20,650
aliyopewa, hujambo backslash 0 ni
kubwa kama kamba ni mfupi

340
00:14:20,650 --> 00:14:22,040
kutosha, kama tano chars.

341
00:14:22,040 --> 00:14:26,470
Lakini kama ni kweli 12 wahusika au
1,200 wahusika, tuliona wakati wa mwisho

342
00:14:26,470 --> 00:14:29,380
kwamba wewe ni kwenda tu kabisa
overwrite kumbukumbu kwamba

343
00:14:29,380 --> 00:14:30,470
siyo wewe.

344
00:14:30,470 --> 00:14:34,390
Na mbaya zaidi kesi, kama wewe overwrite kwamba
nyekundu sehemu pale kwamba sisi kuitwa

345
00:14:34,390 --> 00:14:35,380
kurudi anwani -

346
00:14:35,380 --> 00:14:38,370
hii ni tu ambapo kompyuta
moja kwa moja, kwa ajili yenu, nyuma ya

347
00:14:38,370 --> 00:14:43,130
pazia, tucks mbali thamani ya 32-bit kwamba
kuwakumbusha kwa nini anwani ni lazima

348
00:14:43,130 --> 00:14:47,080
kurudi wakati foo, hii kazi nyingine,
inafanywa utekelezaji.

349
00:14:47,080 --> 00:14:49,320
Ni chembe mkate wa kila aina
ambayo kuirudisha.

350
00:14:49,320 --> 00:14:52,490
Kama wewe overwrite kwamba, uwezekano,
kama wewe ni mtu mbaya, unaweza hawakuweza

351
00:14:52,490 --> 00:14:54,750
uwezekano wa kuchukua
mtu kompyuta.

352
00:14:54,750 --> 00:14:58,020
Na wewe utakuwa hakika
ajali hiyo katika kesi nyingi.

353
00:14:58,020 --> 00:15:01,690
>> Sasa tatizo hii ilikuwa tu exacerbated
kama sisi kuanza kuzungumza juu ya kumbukumbu

354
00:15:01,690 --> 00:15:03,010
usimamizi kwa ujumla zaidi.

355
00:15:03,010 --> 00:15:07,150
Na malloc, kwa ajili ya mgao kumbukumbu, ni
kazi kwamba tunaweza kutumia kutenga

356
00:15:07,150 --> 00:15:11,260
kumbukumbu wakati hatujui mapema
tupate haja ya baadhi ya.

357
00:15:11,260 --> 00:15:13,960
Hivyo, kwa mfano, kama mimi kurejea
kwa appliance hapa.

358
00:15:13,960 --> 00:15:21,010
Na mimi kufungua kutoka hello2.c mara ya mwisho,
kukumbuka mpango huu hapa, ambayo inaonekana

359
00:15:21,010 --> 00:15:23,500
kitu kidogo kama hii,
tatu tu mistari -

360
00:15:23,500 --> 00:15:27,940
hali ya jina lako, basi kamba jina,
upande wa kushoto, sawa GetString.

361
00:15:27,940 --> 00:15:29,690
Na kisha sisi magazeti ya nje,
jina la mtumiaji.

362
00:15:29,690 --> 00:15:31,170
>> Hivyo hii ilikuwa super rahisi mpango.

363
00:15:31,170 --> 00:15:34,870
Kuwa wazi, napenda kwenda mbele
na kufanya hujambo-2.

364
00:15:34,870 --> 00:15:36,680
Mimi naenda kufanya dot kufyeka hujambo-2.

365
00:15:36,680 --> 00:15:37,750
Eleza jina yako -

366
00:15:37,750 --> 00:15:38,140
Daudi.

367
00:15:38,140 --> 00:15:38,840
Kuingia.

368
00:15:38,840 --> 00:15:39,540
Hujambo Daudi.

369
00:15:39,540 --> 00:15:41,060
Inaonekana kazi OK.

370
00:15:41,060 --> 00:15:43,140
Lakini ni nini kweli kinachoendelea
chini ya Hood hapa?

371
00:15:43,140 --> 00:15:44,670
Kwanza hebu peel nyuma tabaka fulani.

372
00:15:44,670 --> 00:15:48,380
Kamba ni kisawe tu tumekuwa
barabara kwa nini?

373
00:15:48,380 --> 00:15:49,110
Char nyota.

374
00:15:49,110 --> 00:15:52,740
Basi hebu kufanya ni kidogo zaidi arcane
lakini zaidi ya utaalamu sahihi kwamba hii

375
00:15:52,740 --> 00:15:55,570
ni nyota Char, ambayo ina maana kwamba
jina, ndiyo, ni kutofautiana.

376
00:15:55,570 --> 00:15:59,920
Lakini nini jina maduka ni anwani ya
Char, ambayo anahisi ajabu kidogo

377
00:15:59,920 --> 00:16:01,050
kwa sababu mimi nina kupata nyuma kamba.

378
00:16:01,050 --> 00:16:03,580
Nina kupata nyuma nyingi
chars si Char.

379
00:16:03,580 --> 00:16:07,400
>> Lakini bila shaka, haja tu ya kwanza
anuani ya Char ya kukumbuka ambapo

380
00:16:07,400 --> 00:16:08,870
kamba nzima ni kwa nini?

381
00:16:08,870 --> 00:16:12,700
Jinsi gani unaweza kufikiri ambapo mwisho wa
kamba ni kujua mwanzo?

382
00:16:12,700 --> 00:16:13,630
sifuri backslash.

383
00:16:13,630 --> 00:16:17,260
Hivyo, pamoja na dalili hizo mbili, unaweza kufikiri
kabla ya mwanzo na mwisho wa

384
00:16:17,260 --> 00:16:20,280
kamba yoyote ni, hivyo muda mrefu kama wao ni
vizuri hutengenezwa kwa null kwamba

385
00:16:20,280 --> 00:16:22,110
Terminator, kwamba sifuri backslash.

386
00:16:22,110 --> 00:16:24,520
>> Lakini hii ni wito GetString.

387
00:16:24,520 --> 00:16:28,020
Na zinageuka kuwa GetString
muda wote huu imekuwa aina ya

388
00:16:28,020 --> 00:16:28,820
cheating kwa ajili yetu.

389
00:16:28,820 --> 00:16:32,460
Imekuwa ni kufanya hii kazi, kuwa na uhakika,
kupata kamba kutoka mtumiaji.

390
00:16:32,460 --> 00:16:34,580
Lakini ambapo wa kumbukumbu kwamba
wamekuwa kuja kutoka?

391
00:16:34,580 --> 00:16:38,440
Kama sisi kurudi nyuma kwa picha hapa na
kuomba ufafanuzi kutoka tu

392
00:16:38,440 --> 00:16:42,610
wakati iliyopita, kwamba ni stack ambapo
kumbukumbu huenda wakati kazi ni wito,

393
00:16:42,610 --> 00:16:45,370
kwa mantiki kwamba, wakati wewe piga GetString,
na kisha mimi aina katika

394
00:16:45,370 --> 00:16:50,900
D-A-V-I-D Kuingia, ambapo ni D-A-V-I-D
backslash sifuri kuhifadhiwa, ya msingi ya

395
00:16:50,900 --> 00:16:53,480
hadithi tumekuwa alituambia mbali?

396
00:16:53,480 --> 00:16:55,190
>> Inaonekana kuwa katika
stack, haki?

397
00:16:55,190 --> 00:16:58,120
Wakati wewe piga kupata kamba ya kupata
kidogo kipande cha kumbukumbu juu ya stack.

398
00:16:58,120 --> 00:17:01,630
Hivyo anasimama kwa kufikiri kwamba D-A-V-I-D
sifuri backslash ni kuhifadhiwa

399
00:17:01,630 --> 00:17:02,770
huko katika stack.

400
00:17:02,770 --> 00:17:07,680
Lakini kusubiri dakika, GetString anarudi
kamba kwamba, ili kuzungumza, ambayo ina maana

401
00:17:07,680 --> 00:17:11,700
ni tray kutoka mkahawa
ni kuchukuliwa mbali stack.

402
00:17:11,700 --> 00:17:14,560
Na sisi alisema mara ya mwisho kwamba haraka kama
kazi anarudi, na kwamba wewe kuchukua

403
00:17:14,560 --> 00:17:20,109
tray, hivyo kusema, mbali stack, nini
unaweza kudhani kuhusu mabaki ya

404
00:17:20,109 --> 00:17:21,819
kwamba kumbukumbu?

405
00:17:21,819 --> 00:17:25,160
Mimi aina ya redrew yao kama alama swali
kwa sababu wao kwa ufanisi kuwa

406
00:17:25,160 --> 00:17:26,250
haijulikani maadili.

407
00:17:26,250 --> 00:17:29,500
Wanaweza kutumika tena wakati baadhi
kazi ya pili ni kuitwa.

408
00:17:29,500 --> 00:17:31,870
>> Kwa maneno mengine, kama sisi kutokea
kuwa hifadhi -

409
00:17:31,870 --> 00:17:34,350
Mimi itabidi kuchora picha ya haraka
hapa ya stack.

410
00:17:34,350 --> 00:17:38,690
Kama sisi kutokea kwa kuwa na kuchora chini
sehemu ya kumbukumbu yangu, na tutaweza kusema

411
00:17:38,690 --> 00:17:42,230
kwamba hii ni sehemu ya kumbukumbu
ulichukua na kuu na labda ARG c na

412
00:17:42,230 --> 00:17:46,790
ARG v na kitu kingine chochote katika mpango,
wakati GetString inaitwa,

413
00:17:46,790 --> 00:17:51,120
labda GetString anapata
chunk ya kumbukumbu hapa.

414
00:17:51,120 --> 00:17:53,940
Na kisha D-A-V-I-D kwa namna fulani
mwisho juu katika kazi hii.

415
00:17:53,940 --> 00:17:55,320
Na mimi nina kwenda oversimplify.

416
00:17:55,320 --> 00:18:00,050
Lakini hebu kudhani kwamba wake-D A-V-I-D
backslash sifuri.

417
00:18:00,050 --> 00:18:03,500
Hivyo ka hii nyingi zinatumika katika
frame kwa GetString.

418
00:18:03,500 --> 00:18:08,270
>> Lakini kwa haraka kama anarudi GetString, sisi
Alisema mara ya mwisho kwamba kumbukumbu hii juu ya

419
00:18:08,270 --> 00:18:11,340
hapa kila inakuwa - woops! -

420
00:18:11,340 --> 00:18:14,270
yote inakuwa ufanisi kufutika.

421
00:18:14,270 --> 00:18:17,220
Na tunaweza kufikiria hili sasa kama swali
alama sababu ambaye anajua

422
00:18:17,220 --> 00:18:18,720
nini kinaendelea kuwa ya kumbukumbu hiyo.

423
00:18:18,720 --> 00:18:22,130
Hakika, mimi mara nyingi sana kuwaita kazi
chochote zaidi GetString.

424
00:18:22,130 --> 00:18:24,750
Na haraka kama mimi wito nyingine
kazi kuliko GetString, labda si katika

425
00:18:24,750 --> 00:18:28,860
mpango huu hasa sisi tu inaonekana
saa lakini baadhi ya wengine, hakika baadhi ya wengine

426
00:18:28,860 --> 00:18:34,180
kazi inaweza kuishia kuwa kutolewa
doa hii ijayo katika stack.

427
00:18:34,180 --> 00:18:39,410
>> Hivyo haiwezi kuwa maduka GetString
D-A-V-I-D juu ya stack kwa sababu napenda

428
00:18:39,410 --> 00:18:41,040
mara moja kupoteza huduma hiyo.

429
00:18:41,040 --> 00:18:43,720
Lakini tunajua wao GetString
tu anarudi nini?

430
00:18:43,720 --> 00:18:47,220
Ni si kurudi
mimi wahusika sita.

431
00:18:47,220 --> 00:18:51,090
Je, ni kwa kweli hakuwa kurudi
twaona mara ya mwisho?

432
00:18:51,090 --> 00:18:52,480
anwani ya kwanza.

433
00:18:52,480 --> 00:18:56,650
Hivyo kwa namna fulani, wakati wewe kuitwa GetString,
ni kugawa chunk ya kumbukumbu kwa

434
00:18:56,650 --> 00:18:59,620
kamba kwamba aina ya watumiaji na
kisha kurudi na anwani yake.

435
00:18:59,620 --> 00:19:02,930
Na zinageuka kuwa wakati unataka
kazi kutenga kumbukumbu katika hii

436
00:19:02,930 --> 00:19:08,390
njia na kurudi kwa mtu ambaye kuitwa
kwamba kazi, anwani ya

437
00:19:08,390 --> 00:19:11,870
kwamba chunk ya kumbukumbu, wewe kabisa
hawawezi kuiweka katika stack katika

438
00:19:11,870 --> 00:19:14,750
chini, kwa sababu functionally ni tu
kwenda si kuwa wako sana

439
00:19:14,750 --> 00:19:17,800
haraka, hivyo pengine unaweza nadhani ambapo
sisi ni pengine kwenda kuwatupia

440
00:19:17,800 --> 00:19:20,130
badala yake, lundo kinachojulikana.

441
00:19:20,130 --> 00:19:25,290
>> Hivyo kati ya chini ya kumbukumbu yako
mpangilio na juu ya kumbukumbu yako ya

442
00:19:25,290 --> 00:19:26,820
layout ni rundo zima la makundi.

443
00:19:26,820 --> 00:19:29,270
Moja ni stack, na haki ya
hapo juu, ni chungu.

444
00:19:29,270 --> 00:19:33,680
Na lundo ni chunk tofauti ya
kumbukumbu kwamba si kutumika kwa ajili ya kazi

445
00:19:33,680 --> 00:19:34,770
wakati wao ni kuitwa.

446
00:19:34,770 --> 00:19:38,100
Ni kutumika kwa ajili ya kumbukumbu ya muda mrefu, wakati
unataka moja ya kazi kwa kunyakua baadhi ya

447
00:19:38,100 --> 00:19:42,700
kumbukumbu na kuwa na uwezo wa hutegemea ni
bila ya kupoteza udhibiti juu yake.

448
00:19:42,700 --> 00:19:45,550
>> Sasa unaweza labda mara moja
kuona kwamba hii si

449
00:19:45,550 --> 00:19:48,060
lazima kubuni kamilifu.

450
00:19:48,060 --> 00:19:51,350
Kama mpango wako zilizotengwa kumbukumbu kwenye
stack, au kama wewe piga zaidi na

451
00:19:51,350 --> 00:19:55,540
zaidi kazi, au kama wewe kutenga
kumbukumbu juu ya lundo na malloc mbali kama

452
00:19:55,540 --> 00:20:00,690
GetString ni kufanya, nini wazi
inaonekana kuwa kuepukika tatizo?

453
00:20:00,690 --> 00:20:00,860
>> Haki.

454
00:20:00,860 --> 00:20:03,150
Kama ukweli kwamba haya mishale
ni akizungumzia kwa kila mmoja

455
00:20:03,150 --> 00:20:04,380
hakuendani.

456
00:20:04,380 --> 00:20:08,630
Na kwa kweli, tunaweza haraka sana ajali
mpango katika idadi yoyote ya njia.

457
00:20:08,630 --> 00:20:12,050
Kwa kweli, nadhani tuwe na
kufanyika hii ajali mara moja.

458
00:20:12,050 --> 00:20:14,020
Au kama si hivyo, hebu kufanya hivyo
makusudi sasa.

459
00:20:14,020 --> 00:20:21,330
Hebu kwenda mbele na kuandika super haraka
programu inayoitwa dontdothis.c.

460
00:20:21,330 --> 00:20:26,730
Na sasa nitakwenda katika hapa na
wala mkali pamoja stdio.h.

461
00:20:26,730 --> 00:20:32,620
Hebu kutangaza kazi foo inachukua
hakuna hoja, ambayo ni

462
00:20:32,620 --> 00:20:34,040
ulionyehsa pamoja na utupu.

463
00:20:34,040 --> 00:20:37,830
>> Na kitu pekee foo ni kwenda kufanya ni
wito foo, ambayo pengine si

464
00:20:37,830 --> 00:20:39,100
smartest wazo, lakini na iwe hivyo.

465
00:20:39,100 --> 00:20:40,490
Ent kuu utupu.

466
00:20:40,490 --> 00:20:45,270
Sasa kitu pekee kuu ni kwenda
kufanya ni kuwaita foo pia.

467
00:20:45,270 --> 00:20:51,050
Na tu kwa mateke, mimi nina kwenda
mbele hapa na kusema printf "Hello kutoka

468
00:20:51,050 --> 00:20:52,340
foo. "

469
00:20:52,340 --> 00:20:52,890
>> OK.

470
00:20:52,890 --> 00:21:00,160
Hivyo kama mimi si kufanya makosa yoyote,
Kufanya dontdothis dot kufyeka.

471
00:21:00,160 --> 00:21:01,960
Na hebu kufanya hivyo katika dirisha kubwa -

472
00:21:01,960 --> 00:21:03,210
dot kufyeka, dontdothis.

473
00:21:03,210 --> 00:21:07,590

474
00:21:07,590 --> 00:21:08,840
Kuja juu.

475
00:21:08,840 --> 00:21:10,940

476
00:21:10,940 --> 00:21:11,890
Uh oh.

477
00:21:11,890 --> 00:21:13,100
Inavyoonekana, unaweza kufanya hivyo.

478
00:21:13,100 --> 00:21:15,190
Damn it.

479
00:21:15,190 --> 00:21:16,190
OK.

480
00:21:16,190 --> 00:21:16,580
Kusubiri.

481
00:21:16,580 --> 00:21:17,370
Kusimama kwa.

482
00:21:17,370 --> 00:21:18,270
Je, sisi -

483
00:21:18,270 --> 00:21:20,110
Hatukuwa kutumia kwa kufanya.

484
00:21:20,110 --> 00:21:22,050
>> [Anapumua]

485
00:21:22,050 --> 00:21:25,110
>> Najua lakini nadhani sisi
tu kwamba imefutwa.

486
00:21:25,110 --> 00:21:28,410
Uh, yeah.

487
00:21:28,410 --> 00:21:30,660
Damn it.

488
00:21:30,660 --> 00:21:32,640
Kutatua Rob.

489
00:21:32,640 --> 00:21:34,678
Nini?

490
00:21:34,678 --> 00:21:35,928
Ni rahisi sana.

491
00:21:35,928 --> 00:21:43,820

492
00:21:43,820 --> 00:21:47,360
Yeah, sisi akageuka optimization mbali.

493
00:21:47,360 --> 00:21:48,970
OK, kusimama bye.

494
00:21:48,970 --> 00:21:49,950
Sasa mimi kujisikia vizuri.

495
00:21:49,950 --> 00:21:51,390
OK.

496
00:21:51,390 --> 00:21:51,780
Wote haki.

497
00:21:51,780 --> 00:21:53,430
>> Basi hebu recompile hii -

498
00:21:53,430 --> 00:21:55,880
Kufanya wewe dontdothis.

499
00:21:55,880 --> 00:22:00,090
Unaweza kuwa na kubadili jina hili
dothis.c katika muda tu.

500
00:22:00,090 --> 00:22:00,710
Kuna sisi kwenda.

501
00:22:00,710 --> 00:22:01,240
Asante.

502
00:22:01,240 --> 00:22:02,050
OK.

503
00:22:02,050 --> 00:22:05,480
Hivyo ukweli kwamba nilikuwa kuchapa
kitu nje alikuwa kweli tu

504
00:22:05,480 --> 00:22:08,150
kupunguza kasi ya mchakato na ambayo sisi
ingekuwa kufikiwa kwamba uhakika.

505
00:22:08,150 --> 00:22:08,510
OK.

506
00:22:08,510 --> 00:22:08,870
Phew!

507
00:22:08,870 --> 00:22:11,180
>> Hivyo ni nini hasa kinachoendelea?

508
00:22:11,180 --> 00:22:14,440
sababu kuna, kama tu kando, ni
kufanya kitu chochote katika suala la pembejeo na

509
00:22:14,440 --> 00:22:17,270
pato huelekea kuwa polepole kwa sababu wewe
kuwa na kuandika herufi kwa

510
00:22:17,270 --> 00:22:18,600
screen, Ina na kitabu.

511
00:22:18,600 --> 00:22:21,720
Hivyo muda mrefu hadithi fupi, alikuwa na mimi kwa kweli
kilichotokea hivyo papara, tunataka kuwa

512
00:22:21,720 --> 00:22:23,260
kuona hii matokeo ya mwisho pia.

513
00:22:23,260 --> 00:22:26,220
Sasa kwa kuwa nilipata safari ya magazeti-ups,
tunaona haki mbali.

514
00:22:26,220 --> 00:22:28,410
Hivyo ni kwa nini hili likitokea.

515
00:22:28,410 --> 00:22:31,300
Naam, maelezo rahisi, bila shaka,
ni kwamba foo pengine lazima si

516
00:22:31,300 --> 00:22:32,500
kuwa wito yenyewe.

517
00:22:32,500 --> 00:22:34,470
>> Sasa kwa ujumla,
hii ni recursion.

518
00:22:34,470 --> 00:22:36,970
Na sisi mawazo wiki kadhaa
iliyopita kujirudia ni nzuri.

519
00:22:36,970 --> 00:22:40,330
Recursion ni njia hii ya kichawi ya
kuonyesha mwenyewe super ufupi.

520
00:22:40,330 --> 00:22:41,400
Na ni kazi tu.

521
00:22:41,400 --> 00:22:45,060
Lakini kuna kipengele muhimu ya yote ya
mipango ya kujirudia tumekuwa aliyesema

522
00:22:45,060 --> 00:22:48,260
kuhusu na inaonekana saa hivi sasa, ambayo
ilikuwa kwamba walikuwa na nini?

523
00:22:48,260 --> 00:22:52,610
kesi ya msingi, ambayo ilikuwa ngumu baadhi coded
kesi hiyo alisema katika baadhi ya hali

524
00:22:52,610 --> 00:22:56,210
wala kuwaita foo, ambayo ni wazi
si kesi hapa.

525
00:22:56,210 --> 00:22:58,920
>> Hivyo kile ni kweli yanatokea
katika suala la picha hii?

526
00:22:58,920 --> 00:23:01,790
Naam, wakati kuu wito foo, ni
anapata kipande cha kumbukumbu.

527
00:23:01,790 --> 00:23:04,150
Wakati foo wito foo, anapata
kipande cha kumbukumbu.

528
00:23:04,150 --> 00:23:06,430
Wakati foo wito foo, anapata kipande.

529
00:23:06,430 --> 00:23:07,080
Anapata kipande.

530
00:23:07,080 --> 00:23:08,120
Anapata kipande.

531
00:23:08,120 --> 00:23:09,460
Sababu foo ni kamwe kurudi.

532
00:23:09,460 --> 00:23:12,160
Sisi ni kamwe kufutwa mmoja wa wale
muafaka kutoka stack.

533
00:23:12,160 --> 00:23:15,930
Hivyo sisi ni unavuma kupitia chungu, si
kutaja ambaye anajua kile kingine, na

534
00:23:15,930 --> 00:23:19,600
sisi ni overstepping mipaka ya yetu ya
kinachojulikana sehemu ya kumbukumbu.

535
00:23:19,600 --> 00:23:21,790
Kosa kwenda segmentation uongo.

536
00:23:21,790 --> 00:23:24,110
>> Hivyo suluhisho kuna
wazi si kufanya hili.

537
00:23:24,110 --> 00:23:28,830
Lakini maana kubwa zaidi ni kwamba, ndiyo,
kuna kabisa ni kikomo fulani,

538
00:23:28,830 --> 00:23:32,470
hata kama siyo vizuri defined, kama jinsi
kazi nyingi unaweza kuwaita katika

539
00:23:32,470 --> 00:23:34,970
mpango, mara ngapi kazi
wanaweza kupiga yenyewe.

540
00:23:34,970 --> 00:23:38,430
Hivyo hata kama tulivyofanya kuhubiri recursion
kama jambo hili uwezekano wa kichawi

541
00:23:38,430 --> 00:23:41,870
michache ya wiki iliyopita kwa ajili ya sigma
kazi, na wakati sisi kupata data

542
00:23:41,870 --> 00:23:45,270
miundo na CS50, utaona nyingine
maombi kwa ajili ya hayo, siyo

543
00:23:45,270 --> 00:23:46,500
lazima kitu bora.

544
00:23:46,500 --> 00:23:50,070
Kwa sababu kama kazi ya wito yenyewe,
wito yenyewe, hata kama kuna msingi

545
00:23:50,070 --> 00:23:54,860
kesi, kama huna hit kwamba kesi ya msingi
kwa ajili ya 1000 au simu wito 10,000, na

546
00:23:54,860 --> 00:23:58,800
kwamba wakati unaweza kuwa na kukimbia nje ya chumba
juu ya kinachojulikana yako stack na kibao

547
00:23:58,800 --> 00:24:00,400
baadhi ya makundi mengine ya kumbukumbu.

548
00:24:00,400 --> 00:24:03,950
Hivyo pia ni kubuni biashara-off
kati ya ulimbwende na kati ya

549
00:24:03,950 --> 00:24:06,920
robustness ya fulani yako
utekelezaji.

550
00:24:06,920 --> 00:24:10,780
>> Hivyo kuna mwingine upande wa chini au
mwingine gotcha kwa nini tumekuwa

551
00:24:10,780 --> 00:24:11,720
wamekuwa wakifanya hivi sasa.

552
00:24:11,720 --> 00:24:12,980
Wakati mimi aitwaye GetString -

553
00:24:12,980 --> 00:24:15,120
napenda kwenda nyuma katika hujambo-2.

554
00:24:15,120 --> 00:24:18,170
Taarifa kwamba mimi nina wito GetString,
ambayo ni ya kurudi anwani.

555
00:24:18,170 --> 00:24:20,730
Na sisi kudai leo kwamba anuani
ni kutoka lundo.

556
00:24:20,730 --> 00:24:24,480
Na sasa mimi ni uchapishaji nje
kamba katika anwani hiyo.

557
00:24:24,480 --> 00:24:27,000
Lakini tumekuwa kamwe kuitwa
kinyume cha GetString.

558
00:24:27,000 --> 00:24:30,850
Tumekuwa kamwe alikuwa calll kazi kama
ungetstring, ambapo mkono nyuma

559
00:24:30,850 --> 00:24:31,610
kwamba kumbukumbu.

560
00:24:31,610 --> 00:24:33,250
Lakini kusema ukweli sisi pengine
ha.

561
00:24:33,250 --> 00:24:37,390
Kwa sababu kama sisi kuendelea kuuliza kompyuta
kwa ajili ya kumbukumbu, kwa njia ya mtu kama

562
00:24:37,390 --> 00:24:40,830
GetString lakini kamwe kuwapa nyuma, hakika
kwamba pia ni amefungwa na kusababisha

563
00:24:40,830 --> 00:24:42,970
matatizo ambapo sisi kukimbia nje ya kumbukumbu.

564
00:24:42,970 --> 00:24:46,140
>> Na kwa kweli, tunaweza kuangalia kwa ajili ya haya
matatizo na zana mpya ambao matumizi

565
00:24:46,140 --> 00:24:47,640
ni fumbo kidogo na aina.

566
00:24:47,640 --> 00:24:50,960
Lakini napenda kwenda mbele na kuzisambaza it up
juu ya screen katika muda tu.

567
00:24:50,960 --> 00:24:56,940
Mimi nina kwenda mbele na kukimbia Valgrind
na parameter ambao kwanza amri

568
00:24:56,940 --> 00:25:00,260
line Hoja ni jina
ya kwamba mpango hujambo-2.

569
00:25:00,260 --> 00:25:02,650
Na kwa bahati mbaya ni
pato ni atrociously

570
00:25:02,650 --> 00:25:04,290
tata kwa sababu hakuna nzuri.

571
00:25:04,290 --> 00:25:06,280
Hivyo tunaona kwamba fujo zote.

572
00:25:06,280 --> 00:25:07,530
Daudi ni hali ya jina langu.

573
00:25:07,530 --> 00:25:09,760
Hivyo kwamba ni mpango
kweli mbio.

574
00:25:09,760 --> 00:25:11,180
Na sasa sisi kupata hii pato.

575
00:25:11,180 --> 00:25:13,400
>> Hivyo Valgrind ni sawa
katika roho kwa GDB.

576
00:25:13,400 --> 00:25:14,950
Siyo debugger per se.

577
00:25:14,950 --> 00:25:16,270
Lakini ni kusahihisha kumbukumbu.

578
00:25:16,270 --> 00:25:20,140
Ni mpango ambayo kukimbia yako
mpango na kukuambia kama wewe aliuliza

579
00:25:20,140 --> 00:25:23,860
kompyuta kwa ajili ya kumbukumbu na kamwe kukabidhiwa
nyuma, na hivyo kwa maana ya kuwa una

580
00:25:23,860 --> 00:25:24,570
uvujaji wa kumbukumbu.

581
00:25:24,570 --> 00:25:26,240
Na kumbukumbu uvujaji huwa na kuwa mbaya.

582
00:25:26,240 --> 00:25:29,120
Na wewe ni watumiaji wa kompyuta na
pengine waliona hii, kama una

583
00:25:29,120 --> 00:25:30,300
Mac au PC.

584
00:25:30,300 --> 00:25:33,730
Je, umewahi kutumia kompyuta yako kwa
wakati na si rebooted katika baadhi ya

585
00:25:33,730 --> 00:25:36,820
siku, au ve tu got mengi ya
kuendesha programu, na jambo damn

586
00:25:36,820 --> 00:25:42,360
kupungua kwa mguu kusaga, au angalau
ni super annoying kutumia, kwa sababu

587
00:25:42,360 --> 00:25:44,350
kila kitu tu got super polepole.

588
00:25:44,350 --> 00:25:46,260
>> Sasa kwamba unaweza kuwa na idadi yoyote ya sababu.

589
00:25:46,260 --> 00:25:49,600
Ni inaweza kuwa kitanzi usio, mdudu katika
kanuni ya mtu, au, zaidi tu, ni

590
00:25:49,600 --> 00:25:53,250
inaweza kuwa na maana kwamba wewe ni kutumia zaidi
kumbukumbu, au kujaribu, kuliko yako

591
00:25:53,250 --> 00:25:54,920
kompyuta kweli ana.

592
00:25:54,920 --> 00:25:57,770
Na labda kuna mdudu katika mpango wa baadhi ya
kwamba kuendelea kuuliza kwa kumbukumbu.

593
00:25:57,770 --> 00:26:02,480
Browsers kwa miaka walikuwa sifa mbaya kwa
hii, kuomba kwa ajili ya kumbukumbu zaidi na zaidi

594
00:26:02,480 --> 00:26:03,870
lakini kamwe kuwapatia nyuma.

595
00:26:03,870 --> 00:26:07,220
Hakika, kama wewe tu na finite
kiasi cha kumbukumbu, huwezi kuuliza

596
00:26:07,220 --> 00:26:09,990
kubwa mara nyingi kwa
baadhi ya kumbukumbu hiyo.

597
00:26:09,990 --> 00:26:13,070
>> Na hivyo nini unaweza kuona hapa, ingawa
tena pato Valgrind ni

598
00:26:13,070 --> 00:26:17,490
usiokuwa tata kwa mtazamo saa
kwanza, hii ni sehemu ya kuvutia.

599
00:26:17,490 --> 00:26:18,890
Chungu -

600
00:26:18,890 --> 00:26:20,060
katika matumizi ya exit.

601
00:26:20,060 --> 00:26:22,810
Hivyo hapa ni kiasi gani kumbukumbu ilikuwa
katika matumizi ya chungu katika

602
00:26:22,810 --> 00:26:24,300
wakati mpango wangu exited -

603
00:26:24,300 --> 00:26:27,280
inaonekana sita ka katika kuzuia moja.

604
00:26:27,280 --> 00:26:28,710
Hivyo nina kwenda kwa wimbi mikono yangu
saa nini kuzuia ni.

605
00:26:28,710 --> 00:26:31,270
Fikiria ni tu chunk, zaidi
kiufundi kwa ajili ya neno chunk.

606
00:26:31,270 --> 00:26:33,140
Lakini sita ka -

607
00:26:33,140 --> 00:26:36,870
kile ni ka sita ambayo
walikuwa bado katika matumizi?

608
00:26:36,870 --> 00:26:37,390
>> Hasa.

609
00:26:37,390 --> 00:26:41,520
D-A-V-I-D backslash sifuri, tano barua
jina plus Terminator null.

610
00:26:41,520 --> 00:26:46,350
Hivyo mpango huu Valgrind niliona kwamba mimi
aliuliza kwa ka sita, inaonekana, na

611
00:26:46,350 --> 00:26:48,950
njia ya GetString, lakini kamwe
akawapa nyuma.

612
00:26:48,950 --> 00:26:52,030
Na kwa kweli, hii inaweza kuwa hivyo
dhahiri kama mpango wangu si tatu

613
00:26:52,030 --> 00:26:53,590
mistari, lakini ni 300 mistari.

614
00:26:53,590 --> 00:26:56,920
Ili tuweze kweli kutoa amri nyingine
line hoja ya Valgrind kwa

615
00:26:56,920 --> 00:26:58,290
kufanya hivyo zaidi verbose.

616
00:26:58,290 --> 00:26:59,760
Ni kidogo annoying kukumbuka.

617
00:26:59,760 --> 00:27:01,580
Lakini kama mimi kufanya -

618
00:27:01,580 --> 00:27:01,930
hebu angalia.

619
00:27:01,930 --> 00:27:03,540
Leak -

620
00:27:03,540 --> 00:27:05,030
Ilikuwa ni kuvuja -

621
00:27:05,030 --> 00:27:07,580
hata sikumbuki
ni nini mbali mkono.

622
00:27:07,580 --> 00:27:08,550
>> - Leak-hundi sawa kamili.

623
00:27:08,550 --> 00:27:10,180
Yep, asante.

624
00:27:10,180 --> 00:27:12,520
- Leak-hundi sawa kamili.

625
00:27:12,520 --> 00:27:13,800
Kuingia.

626
00:27:13,800 --> 00:27:14,940
Mpango huo ni mbio.

627
00:27:14,940 --> 00:27:16,180
Aina katika Daudi tena.

628
00:27:16,180 --> 00:27:17,660
Sasa naona kidogo zaidi kwa undani.

629
00:27:17,660 --> 00:27:20,890
Lakini chini ya muhtasari wa chungu, ambayo
ni sawa na nne - ah,

630
00:27:20,890 --> 00:27:22,120
hii ni aina ya nzuri.

631
00:27:22,120 --> 00:27:25,460
Sasa Valgrind ni kweli kuangalia
vigumu kidogo katika kanuni yangu.

632
00:27:25,460 --> 00:27:29,580
Na ni kusema kwamba, inaonekana,
malloc katika line -

633
00:27:29,580 --> 00:27:30,580
sisi zoom nje.

634
00:27:30,580 --> 00:27:31,980
Katika line -

635
00:27:31,980 --> 00:27:32,930
hatuoni nini mstari ni.

636
00:27:32,930 --> 00:27:35,110
Lakini malloc ni culprit kwanza.

637
00:27:35,110 --> 00:27:38,630
Kuna blog katika malloc.

638
00:27:38,630 --> 00:27:39,810
>> Wote haki?

639
00:27:39,810 --> 00:27:40,450
OK, hakuna.

640
00:27:40,450 --> 00:27:40,940
Haki?

641
00:27:40,940 --> 00:27:42,520
Mimi kuitwa GetString.

642
00:27:42,520 --> 00:27:44,460
GetString inaonekana wito malloc.

643
00:27:44,460 --> 00:27:47,800
Hivyo kile mstari wa kanuni ni inaonekana
katika kosa kwa kuwa na

644
00:27:47,800 --> 00:27:49,050
zilizotengwa kumbukumbu hii?

645
00:27:49,050 --> 00:27:51,560

646
00:27:51,560 --> 00:27:55,540
Hebu kudhani kuwa mtu aliandika malloc
imekuwa karibu muda wa kutosha kwamba ni

647
00:27:55,540 --> 00:27:56,390
si kosa lao.

648
00:27:56,390 --> 00:27:57,520
Hivyo pengine mgodi.

649
00:27:57,520 --> 00:28:02,000
GetString katika cs50.c - hivyo kwamba ni
faili mahali fulani kwenye kompyuta -

650
00:28:02,000 --> 00:28:05,210
katika mstari 286 inaonekana kuwa mhalifu.

651
00:28:05,210 --> 00:28:08,140
Sasa hebu kudhani kwamba cs50 imekuwa
karibu kwa kiasi heshima ya muda, hivyo

652
00:28:08,140 --> 00:28:09,720
sisi pia ni dosari.

653
00:28:09,720 --> 00:28:14,080
Na hivyo pengine si katika GetString
kwamba mdudu uongo, bali katika

654
00:28:14,080 --> 00:28:17,810
hujambo-2.c line 18.

655
00:28:17,810 --> 00:28:20,670
>> Basi hebu tuangalie
nini kuwa mstari wa 18 ilikuwa.

656
00:28:20,670 --> 00:28:21,130
Oh.

657
00:28:21,130 --> 00:28:27,130
Namna fulani line hii si lazima
Buggy, per se, lakini ni sababu

658
00:28:27,130 --> 00:28:28,630
nyuma kwamba uvujaji wa kumbukumbu.

659
00:28:28,630 --> 00:28:32,140
Hivyo super tu, gani shirikishi
kuwa suluhisho hapa?

660
00:28:32,140 --> 00:28:34,710
Kama sisi ni kuuliza kwa ajili ya kumbukumbu, walikuwa kamwe
kutoa ni nyuma, na kwamba inaonekana kuwa

661
00:28:34,710 --> 00:28:37,940
tatizo kwa sababu baada ya muda kompyuta yangu
ili kukimbia nje ya kumbukumbu, ili kupunguza

662
00:28:37,940 --> 00:28:42,110
chini, mambo mabaya kinaweza kutokea, vizuri,
nini rahisi ufumbuzi angavu?

663
00:28:42,110 --> 00:28:43,140
Kutoa tu nyuma.

664
00:28:43,140 --> 00:28:44,770
>> Jinsi gani unaweza bure juu ya kwamba kumbukumbu?

665
00:28:44,770 --> 00:28:49,970
Naam, nashiriki ni rahisi sana
tu kusema jina bure.

666
00:28:49,970 --> 00:28:51,260
Na tumekuwa kamwe kufanyika hii kabla.

667
00:28:51,260 --> 00:28:55,890
Lakini unaweza kimsingi kufikiri ya
bure kama kinyume cha malloc.

668
00:28:55,890 --> 00:28:58,030
bure ni kinyume cha
kugawa kumbukumbu.

669
00:28:58,030 --> 00:28:59,540
Hivyo sasa napenda recompile hii.

670
00:28:59,540 --> 00:29:02,050
Kufanya hujambo-2.

671
00:29:02,050 --> 00:29:04,620
Basi mimi kukimbia tena. hujambo-2 Daudi.

672
00:29:04,620 --> 00:29:07,290
Hivyo inaonekana kufanya kazi katika
hasa kwa njia hiyo.

673
00:29:07,290 --> 00:29:11,180
Lakini kama mimi kurejea Valgrind na kuendesha upya
kwamba amri hiyo hiyo kwa wapya yangu

674
00:29:11,180 --> 00:29:14,720
ulioandaliwa mpango, kuandika
kwa jina langu kama kabla -

675
00:29:14,720 --> 00:29:15,370
nzuri.

676
00:29:15,370 --> 00:29:16,760
Lundo muhtasari -

677
00:29:16,760 --> 00:29:17,740
katika matumizi ya exit -

678
00:29:17,740 --> 00:29:19,370
sifuri ka katika vitalu sifuri.

679
00:29:19,370 --> 00:29:21,840
Na hii ni super nzuri, kila
vitalu lundo walikuwa huru.

680
00:29:21,840 --> 00:29:23,480
Hakuna uvujaji ni iwezekanavyo.

681
00:29:23,480 --> 00:29:27,200
>> Hivyo kuja juu, si kwa Tatizo Set 4,
lakini pamoja na Tatizo Set 5, forensics

682
00:29:27,200 --> 00:29:30,740
na kuendelea, hii pia itakuwa
kipimo cha usahihi wa yako

683
00:29:30,740 --> 00:29:33,630
mpango, kama au una
au hawana uvujaji kumbukumbu.

684
00:29:33,630 --> 00:29:36,900
Lakini nashiriki, si tu unaweza kufikiri
kupitia kwao intuitively, ambayo

685
00:29:36,900 --> 00:29:40,430
ni, arguably, rahisi kwa ajili ya programu ndogo
lakini vigumu kwa ajili ya programu kubwa,

686
00:29:40,430 --> 00:29:43,860
Valgrind, kwa ajili ya programu hizo kubwa,
wanaweza kukusaidia kutambua

687
00:29:43,860 --> 00:29:45,360
tatizo fulani.

688
00:29:45,360 --> 00:29:47,500
>> Lakini kuna tatizo moja nyingine
ambayo yanaweza kina.

689
00:29:47,500 --> 00:29:51,245
Napenda kufungua faili hii hapa, ambayo ni,
tena, mfano kiasi fulani rahisi.

690
00:29:51,245 --> 00:29:53,760
Lakini hebu kuzingatia nini
mpango huu gani.

691
00:29:53,760 --> 00:29:55,190
Hii inaitwa memory.c.

692
00:29:55,190 --> 00:29:58,380
Tutaweza post hii leo baadaye katika
zip ya chanzo kanuni ya leo.

693
00:29:58,380 --> 00:30:01,610
Na taarifa kwamba nina kazi kuitwa
f kwamba inachukua hoja hakuna na

694
00:30:01,610 --> 00:30:02,800
anarudi chochote.

695
00:30:02,800 --> 00:30:07,240
Katika mstari wa 20, mimi nina inaonekana kutangaza
pointer int na kuiita x.

696
00:30:07,240 --> 00:30:09,570
Mimi ni kumshirikisha kurudi
thamani ya malloc.

697
00:30:09,570 --> 00:30:14,590
Na tu kuwa wazi, jinsi wengi ka am
Mimi labda kupata nyuma kutoka malloc

698
00:30:14,590 --> 00:30:17,080
katika hali hii?

699
00:30:17,080 --> 00:30:18,040
>> Pengine 40.

700
00:30:18,040 --> 00:30:18,840
Wapi kupata kwamba kutoka?

701
00:30:18,840 --> 00:30:22,410
Naam, kama unakumbuka kwamba int mara nyingi ni
4 ka, angalau ni katika

702
00:30:22,410 --> 00:30:25,110
appliance, 10 mara 4 ni wazi kuwa ni 40.

703
00:30:25,110 --> 00:30:28,920
Hivyo malloc ni kurudi anwani ya
chunk ya kumbukumbu na hifadhi ya kwamba

704
00:30:28,920 --> 00:30:30,800
kushughulikia hatimaye katika x.

705
00:30:30,800 --> 00:30:32,570
Hivyo kuwa wazi, nini
basi kinachotokea?

706
00:30:32,570 --> 00:30:34,990
Vizuri, basi mimi kubadili nyuma
na picha yetu hapa.

707
00:30:34,990 --> 00:30:38,150
Basi mimi si tu kuteka chini ya yangu
kumbukumbu ya kompyuta, napenda kwenda mbele na

708
00:30:38,150 --> 00:30:42,990
kuteka Mstatili nzima kwamba
inawakilisha yote ya RAM yangu.

709
00:30:42,990 --> 00:30:44,790
>> Tutaweza kusema kwamba stack
ni juu ya chini.

710
00:30:44,790 --> 00:30:47,010
Na kuna sehemu ya asilia katika
data uninitialized.

711
00:30:47,010 --> 00:30:49,880
Lakini nina kwenda tu abstract wale
mambo mengine mbali kama dot, dot dot.

712
00:30:49,880 --> 00:30:53,470
Mimi tu kwenda kwa kutaja hii
kama chungu kwa juu.

713
00:30:53,470 --> 00:30:57,070
Na kisha chini ya picha hii,
kuwakilisha kuu, mimi naenda

714
00:30:57,070 --> 00:30:59,880
kuwapa kumbukumbu vipande
juu ya stack.

715
00:30:59,880 --> 00:31:03,150
Kwa f, mimi naenda kuwapa kipande
ya kumbukumbu juu ya stack.

716
00:31:03,150 --> 00:31:05,140
Sasa, mimi got kushauriana yangu
chanzo kanuni tena.

717
00:31:05,140 --> 00:31:07,170
Je, ni vigezo mitaa kwa kuu?

718
00:31:07,170 --> 00:31:10,710
Inavyoonekana kitu, hivyo kipande kwamba ni
ufanisi tupu au hata kama kubwa

719
00:31:10,710 --> 00:31:11,600
kama nimekuwa inayotolewa yake.

720
00:31:11,600 --> 00:31:15,730
Lakini katika f, nina kutofautiana za mitaa,
ambayo inaitwa x.

721
00:31:15,730 --> 00:31:20,410
Hivyo nina kwenda mbele na kutoa f
chunk ya kumbukumbu, wito ni x.

722
00:31:20,410 --> 00:31:24,680
>> Na sasa malloc ya mara 10 4,
Hivyo malloc 40, ambapo kwamba

723
00:31:24,680 --> 00:31:25,430
kumbukumbu kutoka?

724
00:31:25,430 --> 00:31:27,530
Tumekuwa si kuchora picha
kama hii kabla.

725
00:31:27,530 --> 00:31:31,140
Lakini hebu tuseme kwamba ni ufanisi
kuja kutoka hapa, hivyo moja,

726
00:31:31,140 --> 00:31:33,170
mbili, tatu, nne, tano.

727
00:31:33,170 --> 00:31:34,680
Na sasa nahitaji 40 ya haya.

728
00:31:34,680 --> 00:31:37,540
Hivyo mimi itabidi kufanya dot, dot, dot zinaonyesha
kwamba kuna hata zaidi ya kumbukumbu

729
00:31:37,540 --> 00:31:39,350
kurudi kutoka lundo.

730
00:31:39,350 --> 00:31:40,710
Sasa nini anuani?

731
00:31:40,710 --> 00:31:42,620
Hebu kuchagua holela wetu
kushughulikia kama siku zote -

732
00:31:42,620 --> 00:31:46,310
Ox123, ingawa pengine ni kwenda
kuwa ni kitu tofauti kabisa.

733
00:31:46,310 --> 00:31:50,420
Hiyo ni anuani ya Byte ya kwanza katika
kumbukumbu kwamba mimi nina kuuliza malloc kwa.

734
00:31:50,420 --> 00:31:53,630
>> Hivyo katika line short, mara 20 executes,
kile ni halisi

735
00:31:53,630 --> 00:31:57,170
kuhifadhiwa ndani ya x hapa?

736
00:31:57,170 --> 00:31:58,730
Ox123.

737
00:31:58,730 --> 00:32:00,370
Ox123.

738
00:32:00,370 --> 00:32:01,550
Na ng'ombe ni uninteresting.

739
00:32:01,550 --> 00:32:03,200
Ni tu ina maana hapa ni
hexadesimoli idadi.

740
00:32:03,200 --> 00:32:06,490
Lakini nini muhimu ni kwamba kile nimekuwa kuhifadhi
katika x, ambayo ni kutofautiana mitaa.

741
00:32:06,490 --> 00:32:10,260
Lakini sina data aina, tena,
ni anwani ya int.

742
00:32:10,260 --> 00:32:12,710
Naam, mimi nina kwenda kuhifadhi Ox123.

743
00:32:12,710 --> 00:32:16,610
Lakini tena, kama kwamba ni kidogo sana
ngumu usiokuwa, kama mimi kitabu

744
00:32:16,610 --> 00:32:21,490
nyuma, tunaweza abstract hii mbali kabisa
sababu na kusema tu kwamba ni x

745
00:32:21,490 --> 00:32:23,910
pointer kwamba chunk ya kumbukumbu.

746
00:32:23,910 --> 00:32:24,070
>> OK.

747
00:32:24,070 --> 00:32:26,230
Sasa swali katika mkono
ni yafuatayo -

748
00:32:26,230 --> 00:32:29,910
mstari 21, ni zamu nje, ni Buggy.

749
00:32:29,910 --> 00:32:31,160
Kwa nini?

750
00:32:31,160 --> 00:32:34,890

751
00:32:34,890 --> 00:32:36,930
>> Pole?

752
00:32:36,930 --> 00:32:38,640
Haina -

753
00:32:38,640 --> 00:32:40,390
kusema kwamba kwa mara nyingine.

754
00:32:40,390 --> 00:32:41,240
Naam, haina bure.

755
00:32:41,240 --> 00:32:42,350
Hivyo hiyo ni ya pili lakini.

756
00:32:42,350 --> 00:32:45,000
Hivyo kuna mtu mwingine lakini hasa
katika mstari wa 21.

757
00:32:45,000 --> 00:32:49,480

758
00:32:49,480 --> 00:32:50,040
>> Hasa.

759
00:32:50,040 --> 00:32:54,980
Line hii rahisi ya kanuni ni tu
buffer kufurika, overrun buffer.

760
00:32:54,980 --> 00:32:57,050
buffer tu ina maana chunk ya kumbukumbu.

761
00:32:57,050 --> 00:33:01,520
Lakini kwamba chunk ya kumbukumbu ni ya kawaida
10, 10 integers, ambayo ina maana kama sisi

762
00:33:01,520 --> 00:33:05,350
index ndani yake kwa kutumia sukari kisintaksia
nukuu ya safu, mraba

763
00:33:05,350 --> 00:33:09,220
mabano, unaweza kupata
x mabano mabano 0 x 1 x,

764
00:33:09,220 --> 00:33:10,390
bracket dot, dot, dot.

765
00:33:10,390 --> 00:33:13,270
x 9 mabano ni moja kubwa.

766
00:33:13,270 --> 00:33:17,680
Hivyo kama mimi kufanya x bracket 10, ambapo
Mimi nina kweli kwenda katika kumbukumbu?

767
00:33:17,680 --> 00:33:19,120
>> Naam, kama nina 10 int -

768
00:33:19,120 --> 00:33:21,070
hebu kweli kuteka kila
ya haya hapa.

769
00:33:21,070 --> 00:33:22,700
Ili kwamba ilikuwa mitano ya kwanza.

770
00:33:22,700 --> 00:33:24,660
Hapa ni nyingine tano ints.

771
00:33:24,660 --> 00:33:29,580
Hivyo x mabano 0 ni hapa. x mabano ni 1
hapa. x 9 mabano ni hapa. x bracket

772
00:33:29,580 --> 00:33:37,960
10 ni hapa, ambayo ina maana Mimi ninawaambia,
katika mstari wa 21, kompyuta na kuweka

773
00:33:37,960 --> 00:33:39,400
simu wapi?

774
00:33:39,400 --> 00:33:42,010
idadi 0 wapi?

775
00:33:42,010 --> 00:33:43,380
Naam, ni 0, ndiyo.

776
00:33:43,380 --> 00:33:45,460
Lakini tu ukweli kwamba wake 0
ni aina ya bahati mbaya.

777
00:33:45,460 --> 00:33:47,140
Ni inaweza kuwa idadi
50, kwa ajili ya wote sisi huduma.

778
00:33:47,140 --> 00:33:50,480
Lakini sisi ni kujaribu kuiweka katika mabano x
10, ambayo ni ambapo hii

779
00:33:50,480 --> 00:33:53,700
alama ya swali ni inayotolewa, ambayo
si jambo zuri.

780
00:33:53,700 --> 00:33:57,070
Mpango huu ili vizuri sana
ajali kama matokeo.

781
00:33:57,070 --> 00:33:59,400
>> Sasa, hebu kwenda mbele na kuona kama hii
ni kweli, nini kinatokea.

782
00:33:59,400 --> 00:34:02,600
Kufanya kumbukumbu, tangu faili
inaitwa memory.c.

783
00:34:02,600 --> 00:34:05,950
Hebu kwenda mbele na kukimbia
kumbukumbu mpango.

784
00:34:05,950 --> 00:34:08,239
Hivyo tulipata bahati, kweli, inaonekana.

785
00:34:08,239 --> 00:34:09,340
Tulipata bahati.

786
00:34:09,340 --> 00:34:11,060
Lakini hebu angalia kama sisi sasa kukimbia Valgrind.

787
00:34:11,060 --> 00:34:14,170
Kwa mtazamo wa kwanza, mpango wangu ili
kuonekana kuwa sahihi kabisa.

788
00:34:14,170 --> 00:34:18,010
Lakini basi mimi kukimbia Valgrind na
- Leak-hundi sawa na kamili juu ya kumbukumbu.

789
00:34:18,010 --> 00:34:20,110
>> Na sasa wakati mimi kukimbia hii -

790
00:34:20,110 --> 00:34:21,030
kuvutia.

791
00:34:21,030 --> 00:34:26,800
Batili kuandika ukubwa wa 4 katika
mstari wa 21 memory.c.

792
00:34:26,800 --> 00:34:29,284
Mstari wa 21 memory.c ni ambayo moja?

793
00:34:29,284 --> 00:34:30,340
Oh, kuvutia.

794
00:34:30,340 --> 00:34:31,080
Lakini kusubiri.

795
00:34:31,080 --> 00:34:32,389
Ukubwa 4, nini ni kwamba mnayosema?

796
00:34:32,389 --> 00:34:34,969
Mimi tu hakuwa moja kuandika,
lakini ni ya kawaida 4.

797
00:34:34,969 --> 00:34:36,889
Kwa nini ni 4?

798
00:34:36,889 --> 00:34:39,280
Ni kwa sababu ni int, ambayo
ni, tena, nne ka.

799
00:34:39,280 --> 00:34:42,510
Hivyo Valgrind kupatikana mdudu kuwa mimi,
glancing katika kanuni yangu, hakufanya hivyo.

800
00:34:42,510 --> 00:34:45,040
Na labda TF yako gani au bila.

801
00:34:45,040 --> 00:34:48,469
Lakini kile Valgrind kwa uhakika kupatikana kwamba
tumekuwa alifanya kosa huko, hata

802
00:34:48,469 --> 00:34:52,719
ingawa tulipata bahati, na kompyuta
aliamua, eh, mimi si kwenda kwa ajali

803
00:34:52,719 --> 00:34:57,470
kwa sababu tu wewe kuguswa moja Byte, moja
yenye thamani ya int ya kumbukumbu kwamba hakuwa

804
00:34:57,470 --> 00:34:58,550
kweli mwenyewe.

805
00:34:58,550 --> 00:35:00,380
>> Naam, kile kingine ni Buggy hapa.

806
00:35:00,380 --> 00:35:01,180
Anwani -

807
00:35:01,180 --> 00:35:03,190
hii ni mambo ya kuangalia anuani
katika hexadesimoli.

808
00:35:03,190 --> 00:35:06,890
Hiyo ina maana tu mahali fulani katika lundo ni
sifuri ka baada ya kuzuia wa kawaida 40

809
00:35:06,890 --> 00:35:07,620
ni zilizotengwa.

810
00:35:07,620 --> 00:35:10,610
Hebu zoom nje hapa na kuona kama
hii ni kidogo zaidi kusaidia.

811
00:35:10,610 --> 00:35:11,410
Kuvutia.

812
00:35:11,410 --> 00:35:15,600
Ka 40 ni dhahiri waliopotea
katika hasara rekodi ya 1 ya 1.

813
00:35:15,600 --> 00:35:17,840
Tena, zaidi kuliko maneno ni muhimu hapa.

814
00:35:17,840 --> 00:35:21,350
Lakini kulingana na mistari yalionyesha,
ambapo lazima mimi pengine kuzingatia yangu

815
00:35:21,350 --> 00:35:24,070
tahadhari kwa ajili ya mdudu mwingine?

816
00:35:24,070 --> 00:35:26,570
Inaonekana kama mstari 20 ya memory.c.

817
00:35:26,570 --> 00:35:30,990
>> Hivyo kama sisi kwenda nyuma ya mstari wa 20, kwamba ni
moja kwamba kutambuliwa mapema.

818
00:35:30,990 --> 00:35:33,030
Na si lazima Buggy.

819
00:35:33,030 --> 00:35:35,160
Lakini sisi hii kuachwa madhara yake.

820
00:35:35,160 --> 00:35:38,790
Hivyo ni jinsi gani mimi kusahihisha angalau
moja ya makosa hayo?

821
00:35:38,790 --> 00:35:42,240
Ningefanya nini baada ya mstari 21?

822
00:35:42,240 --> 00:35:47,110
Mimi naweza kufanya bure ya x, hivyo ni
kutoa nyuma kwamba kumbukumbu.

823
00:35:47,110 --> 00:35:49,230
Na jinsi gani mimi kurekebisha hii mdudu?

824
00:35:49,230 --> 00:35:52,120
Mimi lazima dhahiri kwenda
hakuna mbali zaidi kuliko 0.

825
00:35:52,120 --> 00:35:53,670
Hivyo basi mimi kujaribu na kuendesha upya hii.

826
00:35:53,670 --> 00:35:56,080
Samahani, dhahiri kwenda
hakuna mbali zaidi kuliko 9.

827
00:35:56,080 --> 00:35:57,510
Kufanya kumbukumbu.

828
00:35:57,510 --> 00:36:00,650
Hebu rerun Valgrind
katika dirisha kubwa.

829
00:36:00,650 --> 00:36:01,580
Na sasa kuangalia.

830
00:36:01,580 --> 00:36:02,250
Nice.

831
00:36:02,250 --> 00:36:03,270
Vitalu wote lundo walikuwa huru.

832
00:36:03,270 --> 00:36:04,270
Hakuna uvujaji ni iwezekanavyo.

833
00:36:04,270 --> 00:36:07,520
Na hadi hapo juu hapa, kuna hakuna kutaja
yoyote zaidi ya haki batili.

834
00:36:07,520 --> 00:36:09,820
>> Tu kupata tamaa, na hebu
kuona kama mwingine maandamano

835
00:36:09,820 --> 00:36:11,050
haina kwenda kama lengo -

836
00:36:11,050 --> 00:36:12,560
Sikuweza kupata bahati wakati iliyopita.

837
00:36:12,560 --> 00:36:15,530
Na ukweli kwamba hii ni 0 labda ni
usiokuwa na kupotosha.

838
00:36:15,530 --> 00:36:20,650
Hebu tu kufanya 50, holela kiasi fulani
simu, kufanya kumbukumbu dot kufyeka kumbukumbu -

839
00:36:20,650 --> 00:36:21,410
bado kupata bahati.

840
00:36:21,410 --> 00:36:22,510
Kitu ni crashing.

841
00:36:22,510 --> 00:36:26,150
Tuseme mimi tu kufanya kitu kweli
wajinga, na mimi kufanya 100.

842
00:36:26,150 --> 00:36:30,360
Hebu remake kumbukumbu,
dot kufyeka kumbukumbu -

843
00:36:30,360 --> 00:36:31,075
got bahati tena.

844
00:36:31,075 --> 00:36:32,800
Vipi kuhusu 1000?

845
00:36:32,800 --> 00:36:35,370
ints zaidi, takribani,
ambapo mimi lazima?

846
00:36:35,370 --> 00:36:37,410
Kufanya kumbukumbu -

847
00:36:37,410 --> 00:36:38,570
damn it.

848
00:36:38,570 --> 00:36:39,920
>> [Kicheko]

849
00:36:39,920 --> 00:36:41,270
>> OK.

850
00:36:41,270 --> 00:36:43,920
Hebu si fujo karibu tena.

851
00:36:43,920 --> 00:36:45,120
Rerun kumbukumbu.

852
00:36:45,120 --> 00:36:45,840
Kuna sisi kwenda.

853
00:36:45,840 --> 00:36:46,410
Wote haki.

854
00:36:46,410 --> 00:36:52,500
Hivyo inaonekana wewe index ints 100,000
zaidi ambapo unapaswa kuwa katika

855
00:36:52,500 --> 00:36:54,410
kumbukumbu, mambo mabaya kutokea.

856
00:36:54,410 --> 00:36:56,430
Hivyo hii ni wazi si
ngumu, kwa haraka utawala.

857
00:36:56,430 --> 00:36:58,190
Mimi ilikuwa aina ya kutumia kesi
na makosa ya kufika huko.

858
00:36:58,190 --> 00:37:02,230
Lakini hii ni kwa sababu, kwa muda mrefu hadithi fupi,
kumbukumbu ya kompyuta yako pia ni kugawanywa

859
00:37:02,230 --> 00:37:03,580
katika mambo haya kuitwa makundi.

860
00:37:03,580 --> 00:37:07,260
Na wakati mwingine, kompyuta kweli
amewapa ninyi zaidi kidogo ya kumbukumbu

861
00:37:07,260 --> 00:37:08,400
kuliko wewe kuuliza.

862
00:37:08,400 --> 00:37:12,170
Lakini kwa ajili ya ufanisi, ni rahisi tu
kupata kumbukumbu zaidi lakini tu kuwaambia

863
00:37:12,170 --> 00:37:13,780
kwamba wewe ni kupata sehemu yake.

864
00:37:13,780 --> 00:37:16,370
>> Na kama wewe kupata bahati wakati mwingine,
kwa hiyo, unaweza kuwa na uwezo wa kugusa

865
00:37:16,370 --> 00:37:17,795
kumbukumbu kwamba siyo wewe.

866
00:37:17,795 --> 00:37:21,860
Wewe huna kuhakikisha kwamba thamani gani
kuweka pale kukaa pale, kwa sababu

867
00:37:21,860 --> 00:37:25,080
kompyuta bado anadhani si
yako, lakini siyo lazima kwenda

868
00:37:25,080 --> 00:37:29,910
kuikumba sehemu nyingine ya kumbukumbu katika
kompyuta na kushawishi kosa kama

869
00:37:29,910 --> 00:37:31,710
hii moja hapa.

870
00:37:31,710 --> 00:37:32,060
Wote haki.

871
00:37:32,060 --> 00:37:37,240
Maswali yoyote basi juu ya kumbukumbu?

872
00:37:37,240 --> 00:37:37,590
>> Wote haki.

873
00:37:37,590 --> 00:37:40,610
Hebu tuangalie hapa, basi, katika
kitu tumekuwa kuchukua kwa

874
00:37:40,610 --> 00:37:48,361
nafasi kwa muda kabisa, ambayo
ni katika faili hii inaitwa cs50.h.

875
00:37:48,361 --> 00:37:49,420
Hivyo hii ni faili.

876
00:37:49,420 --> 00:37:51,130
Hizi ni baadhi tu rundo zima
ya maoni juu juu.

877
00:37:51,130 --> 00:37:53,900
Na unaweza kuwa inaonekana saa hii kama
wewe poked karibu juu ya appliance.

878
00:37:53,900 --> 00:37:57,000
Lakini zinageuka kuwa wakati wote,
wakati sisi kutumika kwa kutumia kamba kama

879
00:37:57,000 --> 00:38:01,130
kisawe, njia ambayo sisi alitangaza
kisawe kwamba alikuwa na hili

880
00:38:01,130 --> 00:38:03,990
Keyword typedef, kwa ajili ya ufafanuzi aina.

881
00:38:03,990 --> 00:38:07,500
Na sisi ni kimsingi akisema, kufanya
kamba kisawe kwa nyota Char.

882
00:38:07,500 --> 00:38:11,190
Kwamba njia ambayo stack
kuundwa magurudumu haya mafunzo inajulikana kama

883
00:38:11,190 --> 00:38:12,040
kamba.

884
00:38:12,040 --> 00:38:14,830
>> Sasa hapa ni mfano tu
kwa getchar.

885
00:38:14,830 --> 00:38:17,350
Sisi kuwa na kuonekana hivyo kabla, lakini hiyo ni
kweli nini anafanya. getchar

886
00:38:17,350 --> 00:38:19,070
inachukua hakuna hoja, anarudi Char.

887
00:38:19,070 --> 00:38:21,340
getdouble inachukua hoja hakuna,
anarudi mbili.

888
00:38:21,340 --> 00:38:24,440
getfloat inachukua hakuna hoja anarudi,
kuelea, na kadhalika.

889
00:38:24,440 --> 00:38:27,270
GetInt ni katika hapa. getlonglong
ni katika hapa.

890
00:38:27,270 --> 00:38:28,820
Na GetString ni katika hapa.

891
00:38:28,820 --> 00:38:29,420
Na hiyo ni yake.

892
00:38:29,420 --> 00:38:33,080
Line hii ya zambarau ni mwingine Preprocessor
maelekezo kwa sababu ya

893
00:38:33,080 --> 00:38:35,550
hashtag mwanzoni yake.

894
00:38:35,550 --> 00:38:35,870
>> Wote haki.

895
00:38:35,870 --> 00:38:38,380
Hivyo sasa napenda kwenda katika cs50.c.

896
00:38:38,380 --> 00:38:40,400
Na sisi si kuzungumza kwa muda mrefu sana juu ya hili.

897
00:38:40,400 --> 00:38:43,280
Lakini kukupa mtazamo wa nini
kinachoendelea yote hii

898
00:38:43,280 --> 00:38:46,434
muda, niende -

899
00:38:46,434 --> 00:38:48,250
hebu kufanya getchar.

900
00:38:48,250 --> 00:38:51,050
Hivyo getchar ni zaidi ya maoni.

901
00:38:51,050 --> 00:38:52,060
Lakini inaonekana kama hii.

902
00:38:52,060 --> 00:38:54,800
Hivyo hii ni kazi halisi
getchar ambazo tumekuwa

903
00:38:54,800 --> 00:38:56,055
kuchukua kwa nafasi ipo.

904
00:38:56,055 --> 00:38:59,370
Na hata kama sisi si kutumia hii moja
kwamba mara nyingi, kama milele, ni angalau

905
00:38:59,370 --> 00:39:00,470
rahisi kiasi.

906
00:39:00,470 --> 00:39:02,580
Hivyo ni thamani ya kuchukua
haraka kuangalia hapa.

907
00:39:02,580 --> 00:39:06,540
>> Hivyo getchar ina kitanzi usio,
makusudi hivyo inaonekana.

908
00:39:06,540 --> 00:39:10,050
Ni kisha wito - na hii ni aina ya
nzuri utumiaji wa kanuni ya sisi wenyewe aliandika.

909
00:39:10,050 --> 00:39:11,220
Ni wito GetString.

910
00:39:11,220 --> 00:39:12,460
Kwa sababu ni nini
maana ya kupata Char?

911
00:39:12,460 --> 00:39:14,730
Naam, unaweza pia kujaribu kupata
nzima mstari wa maandishi kutoka kwa mtumiaji na

912
00:39:14,730 --> 00:39:16,940
basi tu kuangalia moja
ya wale wahusika.

913
00:39:16,940 --> 00:39:19,170
Katika mstari wa 60, hapa kidogo
kidogo ya hundi sanity.

914
00:39:19,170 --> 00:39:21,610
Kama GetString akarudi null,
basi si kuendelea.

915
00:39:21,610 --> 00:39:22,820
Kitu potoka.

916
00:39:22,820 --> 00:39:28,120
>> Sasa hii ni kiasi fulani annoying lakini
kawaida katika C. Char max pengine

917
00:39:28,120 --> 00:39:29,960
inawakilisha nini tu
msingi juu ya jina lake?

918
00:39:29,960 --> 00:39:31,670
Ni mara kwa mara.

919
00:39:31,670 --> 00:39:36,040
Ni kama thamani numeric ya
kubwa Char unaweza kuwakilisha na

920
00:39:36,040 --> 00:39:40,370
bite moja, ambayo pengine ni ya simu
255, ambayo ni idadi kubwa ya wewe

921
00:39:40,370 --> 00:39:42,720
kuwakilisha bits nane,
kuanzia sifuri.

922
00:39:42,720 --> 00:39:47,460
Hivyo nimekuwa kutumia hii, katika kazi hii, wakati
kuandika kanuni hii, kwa sababu tu

923
00:39:47,460 --> 00:39:51,753
kama kitu fulani kitaenda vibaya katika getchar lakini
madhumuni yake katika maisha ni kurudi

924
00:39:51,753 --> 00:39:54,830
Char, unahitaji kwa namna fulani kuwa na uwezo
kuashiria kwa mtumiaji huyo

925
00:39:54,830 --> 00:39:55,840
kitu potoka.

926
00:39:55,840 --> 00:39:56,970
Hatuwezi kurudi null.

927
00:39:56,970 --> 00:39:58,480
Ni zinageuka kuwa ni pointer null.

928
00:39:58,480 --> 00:40:01,030
Na tena, getchar ina
kurudi Char.

929
00:40:01,030 --> 00:40:04,760
>> Hivyo mkataba, kama kitu fulani kitaenda
vibaya, ni wewe, programu, au katika

930
00:40:04,760 --> 00:40:08,160
kesi hiyo, mimi na maktaba, nilikuwa
kuamua tu kiholela, kama

931
00:40:08,160 --> 00:40:12,230
kitu fulani kitaenda vibaya, mimi naenda
kurudi idadi 255, ambayo ni kweli

932
00:40:12,230 --> 00:40:17,240
ina maana hatuwezi, mtumiaji anaweza si aina
tabia ya kuwakilishwa na

933
00:40:17,240 --> 00:40:21,410
simu 255 kwa sababu tulikuwa na kuiba ni
kama kinachojulikana sentinel thamani kwa

934
00:40:21,410 --> 00:40:23,410
kuwakilisha tatizo.

935
00:40:23,410 --> 00:40:27,010
Sasa zinageuka kuwa tabia 255
si kitu unaweza aina ya

936
00:40:27,010 --> 00:40:28,380
keyboard yako, hivyo ni hakuna mpango mkubwa.

937
00:40:28,380 --> 00:40:30,910
mtumiaji hana taarifa kwamba
Nimekuwa kuibiwa tabia hii.

938
00:40:30,910 --> 00:40:34,620
Lakini kama umewahi kuona katika kurasa mtu juu ya
mfumo wa kompyuta baadhi ya kumbukumbu ya

939
00:40:34,620 --> 00:40:38,560
kila kofia kama mara kwa mara hii kwamba anasema,
katika kesi ya hitilafu hii nguvu ya mara kwa mara

940
00:40:38,560 --> 00:40:42,720
kurudishwa, hiyo ni baadhi ya binadamu wote walifanya
miaka iliyopita ilikuwa kiholela aliamua

941
00:40:42,720 --> 00:40:45,680
kurudi thamani hii maalum na
simu yake ya mara kwa mara katika kesi

942
00:40:45,680 --> 00:40:46,840
kitu fulani kitaenda vibaya.

943
00:40:46,840 --> 00:40:48,580
>> Sasa uchawi hutokea chini hapa.

944
00:40:48,580 --> 00:40:52,600
Kwanza, mimi nina kutangaza katika mstari 67
mbili wahusika, C1 na C2.

945
00:40:52,600 --> 00:40:57,080
Na kisha katika mstari 68, kuna kweli
mstari wa kanuni kwamba ni kukumbusha ya

946
00:40:57,080 --> 00:41:01,140
rafiki yetu printf, kutokana na kwamba ni
gani kuwa asilimia Cs katika quotes.

947
00:41:01,140 --> 00:41:06,490
Lakini taarifa ya nini kinatokea hapa.
sscanf maana kamba Scan -

948
00:41:06,490 --> 00:41:11,690
maana Scan mpangilio
kamba, ergo sscanf.

949
00:41:11,690 --> 00:41:12,590
Hiyo ina maana gani?

950
00:41:12,590 --> 00:41:16,310
Ina maana wewe kupita kwa sscanf kamba.

951
00:41:16,310 --> 00:41:18,420
Na mstari ni chochote
aina user in

952
00:41:18,420 --> 00:41:23,520
Kupita kwa sscanf string format kama
hii kwamba anasema scanf ni nini

953
00:41:23,520 --> 00:41:25,870
wewe matumaini ya mtumiaji typed in

954
00:41:25,870 --> 00:41:29,730
Wewe kisha kupita-katika anwani ya mbili
chunks ya kumbukumbu, katika kesi hii,

955
00:41:29,730 --> 00:41:31,150
kwa sababu mimi na placeholders mbili.

956
00:41:31,150 --> 00:41:34,610
Hivyo nina kwenda kuwapa anuani
ya C1 na anuani ya C2.

957
00:41:34,610 --> 00:41:37,700
>> Na kukumbuka kwamba kutoa kazi
anuani ya variable fulani, nini

958
00:41:37,700 --> 00:41:38,950
Kidokezo?

959
00:41:38,950 --> 00:41:41,400

960
00:41:41,400 --> 00:41:45,050
Nini unaweza kufanya kazi kwamba kama matokeo
ya kutoa ni anwani ya

961
00:41:45,050 --> 00:41:48,170
kutofautiana, kinyume na
kutofautiana yenyewe?

962
00:41:48,170 --> 00:41:49,450
Ni unaweza mabadiliko hayo, haki?

963
00:41:49,450 --> 00:41:53,250
Kama alikuwa mtu ramani ya kimwili
anwani, wanaweza kwenda huko na kufanya

964
00:41:53,250 --> 00:41:54,750
wanataka chochote katika anwani hiyo.

965
00:41:54,750 --> 00:41:55,800
Same wazo hapa.

966
00:41:55,800 --> 00:41:59,950
Kama sisi kupita kwa sscanf, anuani ya mbili
chunks ya kumbukumbu, hata hayo vidogo

967
00:41:59,950 --> 00:42:03,585
kidogo chunks ya kumbukumbu, C1 na C2, lakini
sisi tunasema ni anuani yao,

968
00:42:03,585 --> 00:42:05,170
sscanf unaweza mabadiliko hayo.

969
00:42:05,170 --> 00:42:08,530
>> Hivyo kusudi sscanf katika maisha, kama sisi kusoma
ukurasa mtu, ni kusoma kile

970
00:42:08,530 --> 00:42:13,420
mtumiaji typed katika, matumaini kwa mtumiaji kuwa
typed katika tabia na labda

971
00:42:13,420 --> 00:42:16,470
mwingine tabia, na chochote mtumiaji
typed, tabia ya kwanza inakwenda

972
00:42:16,470 --> 00:42:19,310
hapa, tabia ya pili huenda hapa.

973
00:42:19,310 --> 00:42:22,470
Sasa, kama kando, hii, na wewe ungekuwa
tu kujua hii kutoka nyaraka,

974
00:42:22,470 --> 00:42:25,570
ukweli kwamba mimi kuweka nafasi tupu kuna
tu ina maana kwamba mimi sijali kama

975
00:42:25,570 --> 00:42:28,440
mtumiaji hits bar nafasi chache
mara kabla ya yeye au yeye inachukua

976
00:42:28,440 --> 00:42:30,400
tabia, nina kwenda kwa kupuuza
nafasi yoyote nyeupe.

977
00:42:30,400 --> 00:42:32,510
Hivyo kwamba, najua kutoka
nyaraka.

978
00:42:32,510 --> 00:42:36,570
>> ukweli kwamba kuna pili% c
ikifuatiwa na nafasi nyeupe ni kweli

979
00:42:36,570 --> 00:42:37,410
makusudi.

980
00:42:37,410 --> 00:42:41,190
Nataka kuwa na uwezo wa kuchunguza kama mtumiaji
Star up au hakuwa na kushirikiana.

981
00:42:41,190 --> 00:42:45,630
Hivyo nina matumaini kwamba mtumiaji tu typed
katika tabia moja, kwa hiyo nina matumaini

982
00:42:45,630 --> 00:42:50,640
kwamba sscanf ni tu kwenda na kurudi
thamani 1 sababu, tena, ikiwa mimi kusoma

983
00:42:50,640 --> 00:42:55,400
nyaraka, kusudi sscanf katika
maisha ni kurudi kwa idadi ya

984
00:42:55,400 --> 00:42:59,170
vigezo kwamba walikuwa wamejaa
na pembejeo mtumiaji.

985
00:42:59,170 --> 00:43:02,270
>> Mimi kupita katika vigezo mbili
anwani, C1 na C2.

986
00:43:02,270 --> 00:43:06,420
Nina matumaini, ingawa, kwamba moja tu ya
wao anapata kuuawa kwa sababu kama sscanf

987
00:43:06,420 --> 00:43:11,130
anarudi 2, nini labda
Kidokezo mantiki?

988
00:43:11,130 --> 00:43:14,600
Kwamba mtumiaji hakuwa tu nipe moja
tabia kama mimi aliiambia yake.

989
00:43:14,600 --> 00:43:17,860
Wao pengine typed katika
angalau mbili wahusika.

990
00:43:17,860 --> 00:43:22,430
Hivyo kama mimi badala yake hakuwa na pili
% C, mimi tu alikuwa moja, ambayo

991
00:43:22,430 --> 00:43:25,370
kusema ukweli itakuwa zaidi angavu
mbinu, nadhani mtazamo wa kwanza,

992
00:43:25,370 --> 00:43:30,220
wewe si kwenda kuwa na uwezo wa kuchunguza
kama mtumiaji imekuwa kutoa zaidi

993
00:43:30,220 --> 00:43:31,780
pembejeo kuliko wewe kweli alitaka.

994
00:43:31,780 --> 00:43:34,100
Hivyo hii ni fomu thabiti
ya kuangalia makosa.

995
00:43:34,100 --> 00:43:35,640
>> Lakini taarifa nini mimi hapa.

996
00:43:35,640 --> 00:43:39,970
Mara baada ya mimi nina uhakika kwamba mtumiaji alinipa moja
tabia, mimi huru line, kufanya

997
00:43:39,970 --> 00:43:44,450
kinyume cha GetString, ambayo kwa upande
anatumia malloc, na kisha mimi kurudi

998
00:43:44,450 --> 00:43:51,030
C1, tabia ya kuwa mimi matumaini
mtumiaji zinazotolewa na tu zinazotolewa.

999
00:43:51,030 --> 00:43:54,680
Hivyo haraka glimpsed tu, lakini
maswali yoyote juu ya getchar?

1000
00:43:54,680 --> 00:43:57,450

1001
00:43:57,450 --> 00:43:59,590
Tutaweza kurudi kwa baadhi ya watu wengine.

1002
00:43:59,590 --> 00:44:03,770
>> Naam, napenda kwenda mbele na kufanya hii -
tuseme sasa, tu kuwahamasisha yetu

1003
00:44:03,770 --> 00:44:08,910
majadiliano katika wiki ya pamoja muda, hii
ni faili inayoitwa structs.h.

1004
00:44:08,910 --> 00:44:11,440
Na tena, hii ni ladha
ya kitu ambacho uongo mbele.

1005
00:44:11,440 --> 00:44:13,090
Lakini kumbuka kwamba mengi
hii ni ya maoni.

1006
00:44:13,090 --> 00:44:17,440
Hivyo basi mimi kuonyesha tu
kuvutia sehemu kwa sasa.

1007
00:44:17,440 --> 00:44:18,020
typedef -

1008
00:44:18,020 --> 00:44:19,700
kuna kuwa Keyword sawa tena.

1009
00:44:19,700 --> 00:44:23,100
typedef sisi kutumia kamba ya kutangaza
kama aina maalum data.

1010
00:44:23,100 --> 00:44:27,490
Unaweza kutumia typedef kujenga bidhaa mpya
data aina ambayo haikuwepo wakati

1011
00:44:27,490 --> 00:44:28,570
C ilizuliwa.

1012
00:44:28,570 --> 00:44:32,520
Kwa mfano, int kuja na C. Char
kuja na C. mara mbili kuja na C. Lakini

1013
00:44:32,520 --> 00:44:34,000
hakuna dhana ya mwanafunzi.

1014
00:44:34,000 --> 00:44:37,230
Na bado itakuwa pretty muhimu kuwa
uwezo wa kuandika mpango kwamba maduka

1015
00:44:37,230 --> 00:44:40,440
katika kutofautiana, ID ya mwanafunzi ya simu,
jina lao, na nyumba zao.

1016
00:44:40,440 --> 00:44:42,890
Kwa maneno mengine, tatu vipande
ya data, kama int na

1017
00:44:42,890 --> 00:44:44,420
kamba na kamba nyingine.

1018
00:44:44,420 --> 00:44:48,220
>> Na typedef, nini pretty nguvu
kuhusu hili na sturct Keyword kwa

1019
00:44:48,220 --> 00:44:53,660
muundo, wewe, programu ya mwaka 2013,
kweli anaweza kufafanua yako mwenyewe

1020
00:44:53,660 --> 00:44:57,530
data aina ambayo haikuwepo miaka
iliyopita lakini kwamba kemikali madhumuni yako.

1021
00:44:57,530 --> 00:45:01,910
Na hivyo hapa, katika mistari 13 kupitia 19,
sisi ni kutangaza takwimu mpya aina, kama

1022
00:45:01,910 --> 00:45:04,320
int, lakini wito ni mwanafunzi.

1023
00:45:04,320 --> 00:45:09,310
Na ndani ya kutofautiana hii ni kwenda
kuwa na mambo matatu - int, kamba,

1024
00:45:09,310 --> 00:45:09,930
na kamba.

1025
00:45:09,930 --> 00:45:13,040
Hivyo unaweza kufikiria nini kweli
kilichotokea hapa, ingawa hii ni

1026
00:45:13,040 --> 00:45:17,160
kidogo ya kurahisisha kwa leo,
mwanafunzi kimsingi ni kwenda

1027
00:45:17,160 --> 00:45:19,450
kuangalia kama hii.

1028
00:45:19,450 --> 00:45:22,580
Inaenda kuwa chunk ya
kumbukumbu na kitambulisho, jina

1029
00:45:22,580 --> 00:45:25,580
shamba, na shamba nyumba.

1030
00:45:25,580 --> 00:45:30,670
Na tutaweza kuwa na uwezo wa kutumia chunks wale wa
kumbukumbu na kupata yao kama ifuatavyo.

1031
00:45:30,670 --> 00:45:38,870
>> Kama mimi kwenda katika struct0.c, hapa ni
muda mrefu kiasi, lakini kufuatia

1032
00:45:38,870 --> 00:45:42,630
muundo, ya kificho kwamba
anatumia hila hii mpya.

1033
00:45:42,630 --> 00:45:45,790
Hivyo kwanza, basi mimi kuteka mawazo yako
na sehemu ya kuvutia juu juu.

1034
00:45:45,790 --> 00:45:49,670
Mkali amefafanua wanafunzi 3, anatangaza
mara kwa mara iitwayo wanafunzi na chukueni

1035
00:45:49,670 --> 00:45:53,450
yake kiholela namba 3, tu
hivyo nina wanafunzi watatu kwa kutumia

1036
00:45:53,450 --> 00:45:54,830
mpango huu kwa sasa.

1037
00:45:54,830 --> 00:45:55,960
Hiyo inakuja Kuu.

1038
00:45:55,960 --> 00:45:58,860
Na notisi, jinsi gani mimi kutangaza
safu ya wanafunzi?

1039
00:45:58,860 --> 00:46:00,480
Naam, mimi tu kutumia syntax sawa.

1040
00:46:00,480 --> 00:46:02,110
mwanafunzi wa neno ni wazi kuwa ni mpya.

1041
00:46:02,110 --> 00:46:04,790
Lakini mwanafunzi, darasa, bracket wanafunzi.

1042
00:46:04,790 --> 00:46:06,720
>> Hivyo kwa bahati mbaya kuna mengi
ya utumiaji wa suala hapa.

1043
00:46:06,720 --> 00:46:07,660
Hii ni idadi tu.

1044
00:46:07,660 --> 00:46:09,040
Hivyo hii ni kama kusema tatu.

1045
00:46:09,040 --> 00:46:11,430
Hatari ni yale tu nataka
kuwaita kutofautiana.

1046
00:46:11,430 --> 00:46:12,840
Mimi naweza kuiita wanafunzi.

1047
00:46:12,840 --> 00:46:15,880
Lakini darasa, hii si darasa katika
kitu oriented Java aina ya njia.

1048
00:46:15,880 --> 00:46:17,220
Ni tu darasa la wanafunzi.

1049
00:46:17,220 --> 00:46:20,590
Na aina ya data ya kipengele kila
katika safu kwamba ni mwanafunzi.

1050
00:46:20,590 --> 00:46:23,040
Hivyo hii ni tofauti kidogo
na kutoka kwa kusema kitu

1051
00:46:23,040 --> 00:46:25,250
kama hii, ni tu -

1052
00:46:25,250 --> 00:46:29,500
Mimi kusema nipe wanafunzi watatu
na kuwaita kwamba darasa safu.

1053
00:46:29,500 --> 00:46:29,800
>> Wote haki.

1054
00:46:29,800 --> 00:46:30,680
Sasa hapa ni kitanzi nne.

1055
00:46:30,680 --> 00:46:33,480
Hii guy ya ukoo - iterate
kutoka sifuri hadi kwenye tatu.

1056
00:46:33,480 --> 00:46:35,160
Na hapa ni kipande mpya ya syntax.

1057
00:46:35,160 --> 00:46:37,710
mpango wa kwenda haraka yangu,
binadamu, kutoa ni mwanafunzi

1058
00:46:37,710 --> 00:46:39,200
ID, ambayo ni int.

1059
00:46:39,200 --> 00:46:44,650
Na hapa ni syntax na ambayo unaweza
kuhifadhi kitu katika uwanja ID katika

1060
00:46:44,650 --> 00:46:48,630
eneo darasani mabano I. Hivyo
syntax hii si mpya.

1061
00:46:48,630 --> 00:46:51,450
Hii ina maana tu nipe nane
mwanafunzi katika darasa.

1062
00:46:51,450 --> 00:46:52,940
Lakini ishara hii ni mpya.

1063
00:46:52,940 --> 00:46:56,320
Hadi sasa, tumekuwa haiwezi kutumika dot,
angalau katika kanuni kama hii.

1064
00:46:56,320 --> 00:47:01,490
Hii ina maana kwenda struct inajulikana kama
mwanafunzi na kuweka kitu huko.

1065
00:47:01,490 --> 00:47:05,670
Vile vile, katika mstari huu ujao, 31, kwenda
mbele na kuweka chochote mtumiaji aina

1066
00:47:05,670 --> 00:47:10,530
kwa jina hapa na nini kufanya kwa ajili ya
nyumba, kitu kimoja, kwenda mbele na

1067
00:47:10,530 --> 00:47:13,230
kuiweka katika. nyumba.

1068
00:47:13,230 --> 00:47:15,955
>> Basi ni nini mpango huu
hatimaye kufanya?

1069
00:47:15,955 --> 00:47:17,220
Unaweza kuona teaser kidogo huko.

1070
00:47:17,220 --> 00:47:24,780
Hebu kwenda mbele na kufanya kufanya structs 0
dot kufyeka struct 0, ID ya mwanafunzi 1,

1071
00:47:24,780 --> 00:47:28,250
kusema Daudi Mather, mwanafunzi ID 2.

1072
00:47:28,250 --> 00:47:32,070
Rob Kirkland, mwanafunzi ID 3.

1073
00:47:32,070 --> 00:47:35,010
Lauren Leverit -

1074
00:47:35,010 --> 00:47:38,380
na kitu pekee mpango huu alivyofanya,
ambayo ni haki kabisa holela, ni

1075
00:47:38,380 --> 00:47:40,980
Nilitaka kufanya kitu na data hii,
sasa kwamba nimepata alitufundisha jinsi ya

1076
00:47:40,980 --> 00:47:43,450
kutumia structs, ni mimi tu alikuwa
hii kitanzi ziada hapa.

1077
00:47:43,450 --> 00:47:45,260
Mimi iterate juu ya safu ya wanafunzi.

1078
00:47:45,260 --> 00:47:49,170
Nilikuwa yetu, labda sasa ukoo rafiki,
kamba kulinganisha, stircomp kwa

1079
00:47:49,170 --> 00:47:53,780
kuangalia ni nyumba 8 ya mwanafunzi
sawa na Mather?

1080
00:47:53,780 --> 00:47:56,760
Na kama hivyo, tu magazeti kitu
kiholela kama, ndiyo, ni.

1081
00:47:56,760 --> 00:47:59,430
Lakini tena, tu kunipa fursa
kutumia na kutumia tena na

1082
00:47:59,430 --> 00:48:02,270
kutumia tena hii mpya dot nukuu.

1083
00:48:02,270 --> 00:48:03,250
>> Hivyo anayejali, haki?

1084
00:48:03,250 --> 00:48:06,270
Kuja na mpango wa mwanafunzi ni
kiasi fulani holela, lakini zinageuka

1085
00:48:06,270 --> 00:48:09,800
kwamba tunaweza kufanya mambo muhimu kwa
hii, kwa mfano kama ifuatavyo.

1086
00:48:09,800 --> 00:48:14,600
Hii ni struct ngumu zaidi
katika C. Ni got kadhaa au mashamba zaidi,

1087
00:48:14,600 --> 00:48:15,880
kiasi fulani isiyoeleweka kirahisi jina.

1088
00:48:15,880 --> 00:48:20,110
Lakini kama wameweza milele habari wa graphics
file format kuitwa bitmap, BMP, ni

1089
00:48:20,110 --> 00:48:22,830
zinageuka kuwa bitmap file format
pretty kiasi kwamba inaonekana kama hii.

1090
00:48:22,830 --> 00:48:24,200
Ni kijinga kidogo smiley uso.

1091
00:48:24,200 --> 00:48:27,840
Ni picha ndogo kwamba nimepata zoomed katika
juu ya pretty kubwa ili niweze kuona kila

1092
00:48:27,840 --> 00:48:30,410
ya dots mtu binafsi au saizi.

1093
00:48:30,410 --> 00:48:33,800
Sasa, ni zamu nje tunaweza kuwakilisha
nyeusi dot na, kusema, idadi 0.

1094
00:48:33,800 --> 00:48:35,520
Na dot nyeupe na namba 1.

1095
00:48:35,520 --> 00:48:39,140
>> Hivyo kwa maneno mengine, kama unataka kuteka
Smiley uso na kuokoa kwamba picha katika

1096
00:48:39,140 --> 00:48:42,680
kompyuta, Inatosha kuhifadhi zeros na
ndio kwamba kuangalia kama hii, ambapo,

1097
00:48:42,680 --> 00:48:45,250
tena, ndio ni nyeupe
na zeros ni nyeusi.

1098
00:48:45,250 --> 00:48:48,290
Na kwa pamoja, ikiwa wewe kwa ufanisi na
kujifunga ya ndio na zeros, una

1099
00:48:48,290 --> 00:48:51,030
gridi ya saizi, na kama wewe kuweka
yao nje, una cute

1100
00:48:51,030 --> 00:48:52,560
kidogo smiley uso.

1101
00:48:52,560 --> 00:48:58,150
Sasa, bitmap file format, BMP, ni
ufanisi kwamba chini ya Hood,

1102
00:48:58,150 --> 00:49:00,970
lakini kwa zaidi piseli sot kwamba wewe
kweli anaweza kuwakilisha rangi.

1103
00:49:00,970 --> 00:49:05,170
>> Lakini wakati una kisasa zaidi
file format kama BMP na JPEG na GIF

1104
00:49:05,170 --> 00:49:09,360
na ambayo unaweza kuwa na utambuzi, wale
mafaili ya rekodi kawaida si tu

1105
00:49:09,360 --> 00:49:13,760
kuwa zeros na ndio kwa saizi, lakini
wana baadhi metadata pia -

1106
00:49:13,760 --> 00:49:16,960
meta kwa maana ya kwamba ni kweli
data lakini ni muhimu kuwa na.

1107
00:49:16,960 --> 00:49:21,370
Hivyo hawa mashamba hapa ni ikimaanisha, na
tutaweza kuona hili kwa undani zaidi katika P-kuweka

1108
00:49:21,370 --> 00:49:25,810
5, kwamba kabla ya zeros na wale ambao
kuwakilisha piseli kwa mfano,

1109
00:49:25,810 --> 00:49:29,110
kuna rundo la metadata kama
ukubwa wa picha na

1110
00:49:29,110 --> 00:49:30,250
upana wa picha.

1111
00:49:30,250 --> 00:49:32,910
Na taarifa mimi nina kukwanyua mbali baadhi ya
holela mambo hapa -

1112
00:49:32,910 --> 00:49:34,260
upana na urefu.

1113
00:49:34,260 --> 00:49:36,160
Kidogo kuhesabu na baadhi ya mambo mengine.

1114
00:49:36,160 --> 00:49:37,840
Hivyo kuna baadhi ya metadata katika faili.

1115
00:49:37,840 --> 00:49:41,470
>> Lakini kwa kuelewa jinsi files wamelazwa
nje kwa njia hii, unaweza kweli

1116
00:49:41,470 --> 00:49:45,890
kisha kuendesha picha, kupona picha
kutoka disk, resize images.

1117
00:49:45,890 --> 00:49:47,560
Lakini unaweza si lazima
kuongeza yao.

1118
00:49:47,560 --> 00:49:48,480
Mimi zinahitajika picha.

1119
00:49:48,480 --> 00:49:52,840
Hivyo mimi akarudi RJ hapa, ambaye wewe aliona
juu ya screen kabisa baadhi ya wakati uliopita.

1120
00:49:52,840 --> 00:49:57,160
Na kama mimi kufungua Akitoa hapa, hii ni
kile kinachotokea kama wewe kujaribu kuvuta na

1121
00:49:57,160 --> 00:49:59,380
kuimarisha RJ.

1122
00:49:59,380 --> 00:50:01,480
Yeye si kupata yoyote bora kweli.

1123
00:50:01,480 --> 00:50:06,240
Akitoa sasa ni aina ya blurring ni
kidogo kidogo, tu Gloss juu

1124
00:50:06,240 --> 00:50:11,040
ukweli kwamba RJ haina kupata hasa
kuimarishwa wakati zoom in

1125
00:50:11,040 --> 00:50:13,310
Na kama kufanya hivyo kwa njia hii,
kuona viwanja?

1126
00:50:13,310 --> 00:50:15,490
Yeah, unaweza dhahiri kuona
mraba projector.

1127
00:50:15,490 --> 00:50:17,690
>> Hiyo ni nini kupata wakati kuongeza.

1128
00:50:17,690 --> 00:50:22,570
Lakini katika kuelewa jinsi RJ yetu au
Uso smiley ni kutekelezwa hebu

1129
00:50:22,570 --> 00:50:24,950
kweli kuandika kificho kwamba kuyaharibu
mambo hayo.

1130
00:50:24,950 --> 00:50:29,970
Na nilifikiri ningependa kuishia kwenye kumbuka hii, pamoja na
55 sekunde ya kuongeza kwamba,

1131
00:50:29,970 --> 00:50:31,230
Mimi kuthubutu, kusema badala ya kupotosha.

1132
00:50:31,230 --> 00:50:32,990
>> [Video avspelning]

1133
00:50:32,990 --> 00:50:34,790
>> -Yeye uongo.

1134
00:50:34,790 --> 00:50:38,310
Juu ya nini, mimi sijui.

1135
00:50:38,310 --> 00:50:41,200
>> -Basi je, sisi kujua?

1136
00:50:41,200 --> 00:50:45,280
>> -Kwamba saa 9:15 Ray Santoya
mara kwa ATM.

1137
00:50:45,280 --> 00:50:47,830
>> -Basi swali ni nini
ilikuwa yeye kufanya saa 9:16?

1138
00:50:47,830 --> 00:50:50,750
>> -Risasi millimeter tisa
katika kitu.

1139
00:50:50,750 --> 00:50:52,615
Labda aliona sniper.

1140
00:50:52,615 --> 00:50:54,760
>> -Au alikuwa anafanya kazi pamoja naye.

1141
00:50:54,760 --> 00:50:56,120
>> -Subiri.

1142
00:50:56,120 --> 00:50:57,450
Kwenda nyuma moja.

1143
00:50:57,450 --> 00:50:58,700
>> -Unaona nini?

1144
00:50:58,700 --> 00:51:05,530

1145
00:51:05,530 --> 00:51:09,490
>> -Lete uso wake juu, full screen.

1146
00:51:09,490 --> 00:51:09,790
>> -Wake glasi.

1147
00:51:09,790 --> 00:51:11,040
>> -Kuna kutafakari.

1148
00:51:11,040 --> 00:51:21,790

1149
00:51:21,790 --> 00:51:23,520
>> -Hiyo baseball Neuvitas timu.

1150
00:51:23,520 --> 00:51:24,530
Hiyo ni alama zao.

1151
00:51:24,530 --> 00:51:27,040
>> -Na yeye kuzungumza na mtu yeyote ni
amevaa kwamba koti.

1152
00:51:27,040 --> 00:51:27,530
>> [MWISHO video avspelning]

1153
00:51:27,530 --> 00:51:29,180
>> DAVID J. Malan: Hii mapenzi
kuwa Tatizo Set 5.

1154
00:51:29,180 --> 00:51:30,720
Tutaona wewe wiki ijayo.

1155
00:51:30,720 --> 00:51:32,330
>> MALE SPIKA: Katika CS50 ijayo.

1156
00:51:32,330 --> 00:51:39,240
>> [Crickets chirping]

1157
00:51:39,240 --> 00:51:41,270
>> [Halisi kucheza]