1
00:00:00,000 --> 00:00:10,920
>> [Halisi kucheza]

2
00:00:10,920 --> 00:00:14,680
>> DAVID J Malan: zote haki,
kuwakaribisha nyuma CS50.

3
00:00:14,680 --> 00:00:16,500
Huu ni mwanzo wa wiki mbili.

4
00:00:16,500 --> 00:00:18,940
neno kutoka kwa mmoja wa wetu
marafiki juu ya chuo -

5
00:00:18,940 --> 00:00:22,620
kama una nia, pengine, ama
sasa au katika baadhi mfupi baadaye

6
00:00:22,620 --> 00:00:25,670
hata, kwa mara vizuri zaidi, mafundisho
katikati ya shule wanafunzi kidogo

7
00:00:25,670 --> 00:00:27,680
kitu kuhusu sayansi ya kompyuta,
kufanya kichwa URL hiyo.

8
00:00:27,680 --> 00:00:32,360
Wao ni katika haja hasa hivi sasa ya
walimu, hasa kama una

9
00:00:32,360 --> 00:00:34,700
alikuwa na baadhi ya yatokanayo na sayansi ya kompyuta.

10
00:00:34,700 --> 00:00:38,060
>> Hivyo kukumbuka kuwa wakati wa mwisho, sisi ilianzisha
chache data aina katika C, na

11
00:00:38,060 --> 00:00:40,590
unaweza kuanza kupata yako
mikono chafu na haya hivi sasa

12
00:00:40,590 --> 00:00:41,940
katika tatizo kuweka moja.

13
00:00:41,940 --> 00:00:43,230
Na tulikuwa na Char.

14
00:00:43,230 --> 00:00:49,100
Hivyo katika suala fulani kiufundi, nini
ni Char kama unajua ni leo?

15
00:00:49,100 --> 00:00:51,050
>> Hivyo ni tabia, lakini hebu
kuwa sahihi zaidi sasa.

16
00:00:51,050 --> 00:00:53,735
Tufanye nini maana na tabia
au mtu binafsi Char?

17
00:00:53,735 --> 00:00:56,700

18
00:00:56,700 --> 00:00:59,500
tabia ya mashirika yasiyo ya namba -

19
00:00:59,500 --> 00:01:00,670
hivyo si lazima.

20
00:01:00,670 --> 00:01:04,580
Ni zinageuka kuwa idadi hata, hata
punctuation na barua ni

21
00:01:04,580 --> 00:01:06,980
kuwakilishwa na data hii
aina inayojulikana kama Char.

22
00:01:06,980 --> 00:01:09,440
Hivyo si lazima herufi.

23
00:01:09,440 --> 00:01:11,100
Yeah?

24
00:01:11,100 --> 00:01:12,275
>> Hivyo ni tabia ASCII.

25
00:01:12,275 --> 00:01:15,510
Hivyo kama wewe kufikiri nyuma kwa wiki sifuri, wakati
tulikuwa Byte yetu ya kujitolea

26
00:01:15,510 --> 00:01:19,150
kuja na ama kushikilia mikono yao juu
au si wote, wao kuwakilishwa bits.

27
00:01:19,150 --> 00:01:22,450
Lakini kwa pamoja kama kundi la nane,
wao kuwakilishwa Byte.

28
00:01:22,450 --> 00:01:26,030
Na sisi ilianzisha dhana ya ASCII
katika hotuba hiyo, ambayo tu ni

29
00:01:26,030 --> 00:01:28,170
ramani kati ya idadi na barua.

30
00:01:28,170 --> 00:01:32,010
Na ASCII matumizi, kama wale binadamu
an alisema, nane bits

31
00:01:32,010 --> 00:01:33,660
kuwakilisha tabia.

32
00:01:33,660 --> 00:01:36,890
>> Hivyo ipasavyo, ikiwa nane bits unaweza
kila kuchukua kwenye moja ya maadili mbili -

33
00:01:36,890 --> 00:01:38,010
zero au moja -

34
00:01:38,010 --> 00:01:40,280
hiyo ina maana kulikuwa na uwezekano mbili
kwa mtu huyu -

35
00:01:40,280 --> 00:01:41,230
zero au moja -

36
00:01:41,230 --> 00:01:44,070
mbili kwa ajili ya mtu huyu, mbili kwa ajili ya hii
mtu, mbili kwa ajili ya hii moja.

37
00:01:44,070 --> 00:01:47,450
Hivyo jumla ya mara mbili mara mbili
mara mbili mara mbili mbili -

38
00:01:47,450 --> 00:01:49,700
hivyo wawili wa nane katika jumla.

39
00:01:49,700 --> 00:01:54,320
Hivyo kuna jumla ya idadi ya wahusika
256 inawezekana kwamba unaweza

40
00:01:54,320 --> 00:01:55,750
kuwakilisha na bits nane.

41
00:01:55,750 --> 00:01:59,210
>> Sasa, wale ambao wanazungumza Asia
lugha wapate kujua ya kuwa kuna zaidi

42
00:01:59,210 --> 00:02:02,620
wahusika katika dunia kuliko tu
Kama na Bs na Cs na Ds.

43
00:02:02,620 --> 00:02:06,130
Na hakika, ASCII haina inatosha kwa
mengi ya lugha ya dunia.

44
00:02:06,130 --> 00:02:07,760
Lakini zaidi juu ya kwamba wakati mwingine.

45
00:02:07,760 --> 00:02:11,240
Kwa sasa, kujua kwamba katika C kama unataka
kuwakilisha mbili, kipande cha

46
00:02:11,240 --> 00:02:15,780
punctuation, au tu tabia ya kitu fulani
katika asili, sisi kutumia Char.

47
00:02:15,780 --> 00:02:18,240
Na ni moja Byte au bits nane.

48
00:02:18,240 --> 00:02:19,690
>> Vipi kuhusu int?

49
00:02:19,690 --> 00:02:20,780
Naam, ni int integer.

50
00:02:20,780 --> 00:02:23,175
Jinsi wengi vipande, kama unakumbuka,
mara integer kawaida?

51
00:02:23,175 --> 00:02:25,930

52
00:02:25,930 --> 00:02:27,512
Mtu yeyote kukumbuka?

53
00:02:27,512 --> 00:02:29,600
Hivyo ni kawaida 32.

54
00:02:29,600 --> 00:02:32,120
Ni kweli inategemea kompyuta
kwamba unatumia.

55
00:02:32,120 --> 00:02:35,770
Lakini katika appliance, na katika mengi ya
kompyuta, ni 32 bits au nne

56
00:02:35,770 --> 00:02:37,140
ka - nane mara nne.

57
00:02:37,140 --> 00:02:39,790
Na ints ni tu kutumika kwa ajili ya kuhifadhi
namba, ama hasi,

58
00:02:39,790 --> 00:02:41,610
chanya, au sifuri.

59
00:02:41,610 --> 00:02:45,250
>> Na kama nimepata bits 32 na wewe tu
huduma kuhusu idadi chanya, unaweza

60
00:02:45,250 --> 00:02:48,960
mtu yeyote ballpark jinsi wengi iwezekanavyo
integers kompyuta wanaweza kuwakilisha kutoka

61
00:02:48,960 --> 00:02:51,820
sifuri juu juu?

62
00:02:51,820 --> 00:02:56,130
Hivyo itakuwa mbili hadi 32, ambayo
ni takribani bilioni nne.

63
00:02:56,130 --> 00:02:59,720
Hivyo hawa mamlaka ya mbili ni kwenda kuwa
mara kwa mara mandhari katika sayansi ya kompyuta.

64
00:02:59,720 --> 00:03:03,930
Kama tutaweza kuona, wao ni rahisi kabisa
kufanya kazi na hata kama si kabisa

65
00:03:03,930 --> 00:03:05,790
rahisi kufanya math katika kichwa ya mtu.

66
00:03:05,790 --> 00:03:07,000
>> Hivyo tutaweza kusema takribani bilioni nne.

67
00:03:07,000 --> 00:03:08,620
Sasa, kwa muda mrefu kwa muda mrefu -

68
00:03:08,620 --> 00:03:09,770
unaweza aina ya nadhani.

69
00:03:09,770 --> 00:03:10,480
Ni muda mrefu zaidi ya int.

70
00:03:10,480 --> 00:03:12,440
Jinsi wengi vipande?

71
00:03:12,440 --> 00:03:14,250
Hivyo 64 bits au ka nane.

72
00:03:14,250 --> 00:03:17,480
Hii tu maana unaweza kuwakilisha hata
kubwa ya idadi, kubwa chanya au

73
00:03:17,480 --> 00:03:19,160
kubwa hasi namba.

74
00:03:19,160 --> 00:03:20,060
>> Na vipi kuhusu kuelea?

75
00:03:20,060 --> 00:03:22,260
Hiyo ni hatua yaliyo
thamani ya bits 32.

76
00:03:22,260 --> 00:03:25,180
Hii ni idadi tu halisi, kitu
na uhakika decimal.

77
00:03:25,180 --> 00:03:30,100
Lakini kama wewe badala yake wanahitaji maeneo zaidi
baada ya uhakika decimal au unataka

78
00:03:30,100 --> 00:03:33,720
kuwakilisha idadi kubwa na baadhi ya
sehemu baada yake, unaweza kutumia

79
00:03:33,720 --> 00:03:36,260
mara mbili, ambayo ni 64 bits.

80
00:03:36,260 --> 00:03:38,240
>> Lakini kuna kuvutia
takeaway hapa.

81
00:03:38,240 --> 00:03:42,890
Hivyo kama ints ni mdogo na bits 32 na
hata hutamani muda ni mdogo na 64

82
00:03:42,890 --> 00:03:46,180
bits, kwamba aina ya anaomba swali,
nini kama kweli wanataka kuhesabu

83
00:03:46,180 --> 00:03:48,790
juu kuliko bilioni 4 kwa int?

84
00:03:48,790 --> 00:03:50,330
Naam, wewe tu kutumia muda mrefu.

85
00:03:50,330 --> 00:03:54,200
Lakini nini kama unataka kuhesabu juu
kuliko mbili kwa 64, kutoa au kuchukua?

86
00:03:54,200 --> 00:03:55,810
>> Sasa, hiyo ni idadi kubwa.

87
00:03:55,810 --> 00:03:59,250
Lakini hatimaye, waweza kweli
huduma kuhusu aina hii ya maadili,

88
00:03:59,250 --> 00:04:03,070
hasa kama wewe ni kutumia database
na kuanzia kukusanya kura na kura

89
00:04:03,070 --> 00:04:06,190
na kura ya data na kumshirikisha kipekee
idadi ya kila kipande cha data hizo.

90
00:04:06,190 --> 00:04:07,430
Hivyo sisi aina ya kuwa na tatizo.

91
00:04:07,430 --> 00:04:10,700
Na vile vile, kwa uhakika na yaliyo
maadili - ikifungwa au mara mbili -

92
00:04:10,700 --> 00:04:14,290
kama wameweza tu got idadi mahususi ya
bits, jinsi wengi uanachama namba ungeli

93
00:04:14,290 --> 00:04:16,980
uwezekano wa kuwakilisha?

94
00:04:16,980 --> 00:04:19,540
>> Naam, ni chini ya wazi wakati
kuhusisha uhakika decimal.

95
00:04:19,540 --> 00:04:20,899
Lakini ni hakika finite.

96
00:04:20,899 --> 00:04:24,390
Kama una idadi mahususi ya vipande,
idadi mahususi ya binadamu, finite

97
00:04:24,390 --> 00:04:27,350
idadi ya balbu mwanga, hakika unaweza
tu kuwakilisha idadi mahususi ya

98
00:04:27,350 --> 00:04:28,510
yaliyo kumweka maadili.

99
00:04:28,510 --> 00:04:33,170
Lakini jinsi wengi kweli idadi
ni yao katika dunia?

100
00:04:33,170 --> 00:04:33,680
Kuna usio.

101
00:04:33,680 --> 00:04:37,280
Hivyo kwamba ni aina ya tatizo kwa sababu sisi
hawana kiasi usio wa

102
00:04:37,280 --> 00:04:39,970
kumbukumbu au RAM ndani ya kompyuta yetu.

103
00:04:39,970 --> 00:04:41,780
Hivyo baadhi ya mambo changamoto yanaweza kutokea.

104
00:04:41,780 --> 00:04:43,900
>> Basi hebu kwenda mbele na kujaribu
kueleza hii hapa.

105
00:04:43,900 --> 00:04:46,240
Hebu kwenda mbele na kufungua gedit.

106
00:04:46,240 --> 00:04:50,360
Mimi nina kwenda mbele na kuokoa faili
inayoitwa "floats0.c" tu kuwa

107
00:04:50,360 --> 00:04:54,630
sambamba na mfano kwamba ni
inapatikana online, kama ungependa.

108
00:04:54,630 --> 00:04:58,080
Na mimi nina kwenda mbele na
kufafanua ni kama ifuatavyo -

109
00:04:58,080 --> 00:05:01,540
Mimi nina kwenda mbele na kusema, int
kuu batili, kama sisi mara nyingi kufanya.

110
00:05:01,540 --> 00:05:07,190
>> Na kisha katika mpango huu, nina kwenda kwa
kutangaza mwenyewe kuelea, hivyo 32-bit

111
00:05:07,190 --> 00:05:09,700
variable kuitwa f, kiholela.

112
00:05:09,700 --> 00:05:13,910
Na basi mimi nina kwenda kuhifadhi ndani yake
Sijui, moja ya kumi, hivyo 0.1.

113
00:05:13,910 --> 00:05:16,590
Hivyo nina kwenda kueleza kwamba kama moja
kugawanywa na 10, ambayo ni kikamilifu

114
00:05:16,590 --> 00:05:17,790
halali katika C.

115
00:05:17,790 --> 00:05:20,460
>> Na kisha juu ya mstari wa pili, mimi tu
unataka magazeti nje kwamba thamani.

116
00:05:20,460 --> 00:05:22,950
Hivyo kukumbuka kwamba tunaweza kutumia
ukoo printf.

117
00:05:22,950 --> 00:05:25,420
Hatutaki kutumia% i kwa int.

118
00:05:25,420 --> 00:05:28,360
Tunataka kutumia% f kwa kuelea.

119
00:05:28,360 --> 00:05:33,080
Na kisha mimi naenda kufanya backslash n,
karibu quote, comma, f, semicolon.

120
00:05:33,080 --> 00:05:34,400
>> Hivyo hapa ni mpango wangu.

121
00:05:34,400 --> 00:05:35,820
Tayari kuna moja mdudu.

122
00:05:35,820 --> 00:05:38,640
Je, mtu ambaye hii clicked
tayari wanataka kwa uhakika angalau

123
00:05:38,640 --> 00:05:40,220
moja mdudu Nimekuwa alifanya?

124
00:05:40,220 --> 00:05:42,470
Yeah?

125
00:05:42,470 --> 00:05:42,800
Yeah.

126
00:05:42,800 --> 00:05:47,860
Nimesahau "# pamoja" katika
juu, wao dalili ya ambayo kama mimi kujaribu

127
00:05:47,860 --> 00:05:50,490
kukusanya hii ni kwenda kuwa kwamba
mkusanyaji ni kwenda yell saa yangu,

128
00:05:50,490 --> 00:05:52,770
akisema ishara kisichojulikana au
kitu na athari hiyo.

129
00:05:52,770 --> 00:05:55,360
Haina kuelewa kitu
kama printf.

130
00:05:55,360 --> 00:05:59,380
>> Hivyo nina kwenda kufanya "ni pamoja na #
", Ila faili.

131
00:05:59,380 --> 00:06:00,400
Na sasa ni katika sura bora.

132
00:06:00,400 --> 00:06:02,690
Lakini nina uhakika pia kwenda
nje ya mwezi mmoja undani leo.

133
00:06:02,690 --> 00:06:08,620
Mbali na kubainisha nafasi ya
wamiliki kama% s f% i%, unaweza

134
00:06:08,620 --> 00:06:12,320
wakati mwingine kuathiri tabia
placeholder ya kwamba.

135
00:06:12,320 --> 00:06:15,540
Kwa mfano, katika kesi ya floating
hatua thamani, kama mimi nataka tu

136
00:06:15,540 --> 00:06:22,200
kuonyesha moja decimal mahali baada ya
kipindi, siwezi kwa kweli kufanya 0.1f.

137
00:06:22,200 --> 00:06:26,830
Hivyo kwa maneno mengine, mimi kutenganisha f na
ishara na asilimia 0.1, tu

138
00:06:26,830 --> 00:06:30,200
kuwaambia printf, unaweza kuwa mzima
rundo la idadi baada ya decimal

139
00:06:30,200 --> 00:06:30,930
uhakika kwa ajili yangu.

140
00:06:30,930 --> 00:06:32,870
Lakini mimi tu wanataka kuona mmoja wao.

141
00:06:32,870 --> 00:06:36,280
>> Hivyo nina kwenda mbele sasa na kuokoa
mpango huu, kwenda katika terminal yangu

142
00:06:36,280 --> 00:06:41,870
dirisha, na mimi nina kwenda mbele
na aina ya kufanya kuelea 0, kuingia.

143
00:06:41,870 --> 00:06:44,930
Mimi naona kuwa mstari fulani fumbo kwamba
wataanza kufanya maana zaidi kama sisi

144
00:06:44,930 --> 00:06:46,900
tease ni mbali wiki hii na ijayo.

145
00:06:46,900 --> 00:06:50,480
Sasa mimi nina kwenda mbele
na kukimbia kuelea sifuri.

146
00:06:50,480 --> 00:06:52,020
Na, damn.

147
00:06:52,020 --> 00:06:54,880
>> Hivyo kuna mdudu mwingine
hapa kwa sababu fulani.

148
00:06:54,880 --> 00:07:02,490
Mimi nina uhakika kwamba pretty moja ya kumi, au
moja kugawanywa na 10, si 0.0.

149
00:07:02,490 --> 00:07:04,590
Labda mimi nina si tu kuangalia
katika maadili ya kutosha.

150
00:07:04,590 --> 00:07:08,580
Hivyo kwa nini nasema mbili 0.2 kuona mbili
decimal maeneo badala ya moja tu.

151
00:07:08,580 --> 00:07:11,810
Hebu nirejee nyuma kwa terminal dirisha yangu
hapa na kugonga juu ya wanandoa wa mara kwa

152
00:07:11,810 --> 00:07:12,840
kuona historia yangu.

153
00:07:12,840 --> 00:07:15,910
Kufanya kufanya kuelea sifuri tena,
na kisha tena.

154
00:07:15,910 --> 00:07:17,730
Na sasa kuingia.

155
00:07:17,730 --> 00:07:20,000
>> Na sasa mimi nina uhakika pretty hii ni sahihi.

156
00:07:20,000 --> 00:07:23,030
Na mimi naweza kufanya tatu na nne, na mimi nina
pengine ataendelea kuona zeros.

157
00:07:23,030 --> 00:07:24,880
Hivyo ambapo ni mdudu?

158
00:07:24,880 --> 00:07:27,910
Moja kugawanywa na 10 lazima 0.1.

159
00:07:27,910 --> 00:07:30,310
Mtu unataka kuchukua kumchoma katika kile
suala la msingi ni?

160
00:07:30,310 --> 00:07:32,400
Yeah?

161
00:07:32,400 --> 00:07:33,420
Wao ni wote integers.

162
00:07:33,420 --> 00:07:33,920
Basi ni nini?

163
00:07:33,920 --> 00:07:37,820
Hivyo kwa moja kugawanywa na 10, hiyo ni
nini mimi katika hesabu.

164
00:07:37,820 --> 00:07:41,185
Na mimi kupata 0.1.

165
00:07:41,185 --> 00:07:41,660
>> Yeah.

166
00:07:41,660 --> 00:07:43,240
Na hivyo ni kweli kwamba suala hilo.

167
00:07:43,240 --> 00:07:46,700
Wakati kuchukua integer katika kompyuta
na wewe kuigawanya na integer mwingine,

168
00:07:46,700 --> 00:07:50,430
kompyuta na default ni kwenda
kudhani kwamba unataka integer.

169
00:07:50,430 --> 00:07:54,620
tatizo ingawa, bila shaka, ni
kwamba 0.1 si integer.

170
00:07:54,620 --> 00:07:55,680
Ni idadi halisi.

171
00:07:55,680 --> 00:07:59,610
Na hivyo kile kompyuta gani na
default ni kama tu imeutupa mbali

172
00:07:59,610 --> 00:08:01,070
kila kitu baada ya uhakika decimal.

173
00:08:01,070 --> 00:08:03,380
Haina pande zote chini au juu per se.

174
00:08:03,380 --> 00:08:06,480
Ni tu imeutupa mbali kila kitu
baada ya uhakika decimal.

175
00:08:06,480 --> 00:08:07,430
Na sasa kwamba hufanya akili.

176
00:08:07,430 --> 00:08:09,740
Kwa sababu sasa sisi ni wazi
kushoto na sifuri.

177
00:08:09,740 --> 00:08:10,250
>> Lakini kusubiri dakika.

178
00:08:10,250 --> 00:08:11,840
Nina kuona sifuri int.

179
00:08:11,840 --> 00:08:14,910
Mimi kwa kweli kuona 0.00.

180
00:08:14,910 --> 00:08:16,340
Hivyo ni jinsi gani mimi kupatanisha hii sasa?

181
00:08:16,340 --> 00:08:22,850
Kama moja kugawanywa na 10 ni sifuri, lakini nina
kuona 0.00, ambapo ni hivyo kupata

182
00:08:22,850 --> 00:08:24,250
waongofu nyuma idadi halisi?

183
00:08:24,250 --> 00:08:25,500
Yeah.

184
00:08:25,500 --> 00:08:29,850

185
00:08:29,850 --> 00:08:30,630
Hasa.

186
00:08:30,630 --> 00:08:35,600
>> Hivyo hapa katika mstari tano, wakati mimi kwa kweli
kuhifadhi kwamba 0.1, ambayo ni kisha

187
00:08:35,600 --> 00:08:39,549
truncated na sifuri, ndani ya kuelea,
hiyo ni sawa na ufanisi

188
00:08:39,549 --> 00:08:42,100
hifadhi hiyo si kama int lakini,
kweli kweli, kama kuelea.

189
00:08:42,100 --> 00:08:46,540
Aidha, mimi nina kisha kwa kutumia printf kwa
waziwazi magazeti kwamba idadi ya mbili

190
00:08:46,540 --> 00:08:49,740
decimal maeneo hata kama kuna
ili si kweli kuwa yoyote.

191
00:08:49,740 --> 00:08:51,020
>> Hivyo aina hii ya sucks, haki?

192
00:08:51,020 --> 00:08:53,640
Inavyoonekana huwezi kufanya math,
angalau katika ngazi hii ya

193
00:08:53,640 --> 00:08:55,600
usahihi, katika kompyuta.

194
00:08:55,600 --> 00:08:56,930
Lakini hakika kuna ufumbuzi.

195
00:08:56,930 --> 00:09:00,410
Nini kurekebisha rahisi tunaweza labda
kufanya, hata tu intuitively hapa

196
00:09:00,410 --> 00:09:01,130
kutatua hili?

197
00:09:01,130 --> 00:09:02,380
Yeah?

198
00:09:02,380 --> 00:09:04,700

199
00:09:04,700 --> 00:09:06,574
Kugeuka integers katika -

200
00:09:06,574 --> 00:09:06,976
yeah.

201
00:09:06,976 --> 00:09:10,420
Hata kama mimi nina uhakika kabisa nini
kweli kinachoendelea hapa, ikiwa ni

202
00:09:10,420 --> 00:09:13,440
kimsingi ina nini na hizi zote mbili
kuwa ints, vizuri, kwa nini si mimi

203
00:09:13,440 --> 00:09:18,230
kufanya 10.0, na kufanya hii
1.0, resave faili.

204
00:09:18,230 --> 00:09:20,990
Hebu kwenda nyuma chini ya
chini na recompile.

205
00:09:20,990 --> 00:09:23,030
Hebu sasa rerun.

206
00:09:23,030 --> 00:09:23,420
Na huko -

207
00:09:23,420 --> 00:09:27,690
sasa, mimi nimepata yangu moja ya kumi
kuwakilishwa kama 0.10.

208
00:09:27,690 --> 00:09:28,420
>> Wote haki.

209
00:09:28,420 --> 00:09:29,220
Hivyo hiyo si mbaya.

210
00:09:29,220 --> 00:09:31,730
Na napenda kumweka nje moja kwa njia nyingine
tunaweza kuwa na kutatuliwa hii.

211
00:09:31,730 --> 00:09:35,580
Hebu kweli unaendelea nyuma katika wakati
kwa wakati tulikuwa hii kama moja

212
00:09:35,580 --> 00:09:36,680
kumi wakati iliyopita.

213
00:09:36,680 --> 00:09:40,800
Na napenda kwenda mbele na resave faili hii
kama tofauti faili jina, tu

214
00:09:40,800 --> 00:09:41,750
kuwa eneo la kukagua kidogo.

215
00:09:41,750 --> 00:09:43,450
Ili kwamba ilikuwa toleo moja.

216
00:09:43,450 --> 00:09:45,520
Na sasa napenda kwenda mbele na
kufanya moja zaidi version.

217
00:09:45,520 --> 00:09:48,540
Tutamwita toleo hili
mbili sifuri indexed.

218
00:09:48,540 --> 00:09:51,280
>> Na mimi nina kwenda badala kufanya
hii - unajua nini?

219
00:09:51,280 --> 00:09:54,400
Kuongeza nukta sifuri kazi katika kesi hii.

220
00:09:54,400 --> 00:09:56,060
Lakini tuseme moja walikuwa kutofautiana.

221
00:09:56,060 --> 00:09:57,680
Zinatakiwa 10 walikuwa kutofautiana.

222
00:09:57,680 --> 00:10:00,680
Kwa maneno mengine, tuseme kwamba sikuweza
tu ngumu-kanuni 0.0 mwishoni

223
00:10:00,680 --> 00:10:02,340
hii ya kujieleza hesabu.

224
00:10:02,340 --> 00:10:05,820
Naam, mimi kweli anaweza kufanya kitu
katika mabano aitwaye akitoa.

225
00:10:05,820 --> 00:10:11,920
Siwezi kutupwa kwamba integer 10 hadi kuelea,
na mimi unaweza kutupwa kwamba mmoja integer kwa

226
00:10:11,920 --> 00:10:12,800
kuelea, kama vile.

227
00:10:12,800 --> 00:10:17,190
Kisha math kwamba kinaendelea kufanyika
ni ufanisi 1.0 kugawanywa na 10.0,

228
00:10:17,190 --> 00:10:19,250
matokeo ya ambayo inakwenda
katika f kama kabla.

229
00:10:19,250 --> 00:10:26,130
Hivyo kama mimi recompile hii kama kufanya ikifungwa
2, na sasa ikifungwa 2, mimi kupata huo

230
00:10:26,130 --> 00:10:27,020
kujibu, kama vile.

231
00:10:27,020 --> 00:10:29,640
>> Hivyo hii ni mfano haki contrived,
kutatua tatizo hili

232
00:10:29,640 --> 00:10:31,400
kwa kuanzisha akitoa.

233
00:10:31,400 --> 00:10:34,410
Lakini kwa ujumla, akitoa kinaendelea kuwa
Jambo nguvu, hasa kwa

234
00:10:34,410 --> 00:10:38,180
tatizo kuweka mbili katika muda wa wiki, wakati
unataka kubadilisha data aina moja kwa

235
00:10:38,180 --> 00:10:41,800
mwingine kwamba mwisho wa siku
ni kuwakilishwa katika njia hiyo hiyo.

236
00:10:41,800 --> 00:10:44,970
Mwisho wa siku, kila moja
Jambo tumekuwa kuongelea hivi sasa ni

237
00:10:44,970 --> 00:10:46,710
tu ints chini ya Hood.

238
00:10:46,710 --> 00:10:48,950
Au kama kwamba ni pia ngazi ya chini kwa
wewe, wao ni idadi tu na

239
00:10:48,950 --> 00:10:49,750
chini ya Hood.

240
00:10:49,750 --> 00:10:52,850
Hata wahusika, tena, kukumbuka
kutoka sifuri kwa wiki, ni idadi

241
00:10:52,850 --> 00:10:53,990
chini ya Hood.

242
00:10:53,990 --> 00:10:57,240
>> Ambayo ni kusema, tunaweza kubadilisha kati ya
aina tofauti ya idadi kama

243
00:10:57,240 --> 00:10:58,060
wao ni tu bits.

244
00:10:58,060 --> 00:11:01,020
Tunaweza kuwabadili kati ya idadi
na barua kama uko tu

245
00:11:01,020 --> 00:11:02,580
bits, na kinyume chake.

246
00:11:02,580 --> 00:11:07,170
Na akitoa katika njia hii ni utaratibu
katika programu ambayo inakuwezesha waliolazimishwa

247
00:11:07,170 --> 00:11:10,970
mabadiliko ya data aina moja hadi nyingine.

248
00:11:10,970 --> 00:11:14,570
Kwa bahati mbaya, hii si kama
moja kwa moja kama mimi ili walipenda.

249
00:11:14,570 --> 00:11:19,220
>> Mimi nina kwenda nyuma katika ikifungwa
1, ambayo ilikuwa rahisi, zaidi

250
00:11:19,220 --> 00:11:22,830
moja kwa moja moja na
0.0 aliongeza juu ya kila aina.

251
00:11:22,830 --> 00:11:25,260
Na tu kama rejea ya haraka,
napenda kwenda mbele na recompile

252
00:11:25,260 --> 00:11:27,670
hii, kufanya ikifungwa 2 -

253
00:11:27,670 --> 00:11:30,300
sorry, hii ni kufanya ikifungwa 1.

254
00:11:30,300 --> 00:11:32,050
Na sasa hebu kukimbia ikifungwa 1.

255
00:11:32,050 --> 00:11:34,810
Na katika sehemu ya chini, taarifa
kwamba mimi kwa kweli kupata 0.1.

256
00:11:34,810 --> 00:11:36,165
Hivyo, tatizo kutatuliwa.

257
00:11:36,165 --> 00:11:37,280
>> Lakini bado.

258
00:11:37,280 --> 00:11:40,000
Mimi sasa kwenda kupata kidogo curious,
na mimi nina kwenda nyuma katika wangu

259
00:11:40,000 --> 00:11:41,620
printf taarifa na
kusema, unajua nini?

260
00:11:41,620 --> 00:11:44,090
Ningependa kuthibitisha kwamba hii
ni kweli moja ya kumi.

261
00:11:44,090 --> 00:11:47,890
Na mimi nina kwenda wanataka kuona hii
, kusema, tano maeneo decimal.

262
00:11:47,890 --> 00:11:48,570
Siyo tatizo.

263
00:11:48,570 --> 00:11:52,020
Mimi kubadili 04:58,
Mimi recompile na kufanya.

264
00:11:52,020 --> 00:11:53,770
Mimi rerun kama ikifungwa 1.

265
00:11:53,770 --> 00:11:54,990
Kuangalia nzuri.

266
00:11:54,990 --> 00:11:58,570
Sanity yangu hundi ili mwisho huko, lakini
Nina kupata zaidi kidogo adventurous.

267
00:11:58,570 --> 00:12:00,330
Mimi nina kwenda na mabadiliko .5-0.10.

268
00:12:00,330 --> 00:12:03,440
Nataka kuona maadili 10 baada ya
nafasi decimal.

269
00:12:03,440 --> 00:12:09,060
>> Na mimi nina kwenda mbele na recompile
hii na rerun ikifungwa 1.

270
00:12:09,060 --> 00:12:13,060
Mimi aina ya majuto baada ya kupima hii
zaidi kwa sababu math yangu si hivyo

271
00:12:13,060 --> 00:12:14,320
kusahihisha tena, inaonekana.

272
00:12:14,320 --> 00:12:15,630
Lakini kusubiri dakika, labda
kwamba tu fluke.

273
00:12:15,630 --> 00:12:17,810
Labda kompyuta ni kaimu
kidogo ya ajabu.

274
00:12:17,810 --> 00:12:21,810
Napenda kwenda mbele na kufanya pointi 20 decimal
na kuwahakikishia kwamba mimi mwenyewe kujua

275
00:12:21,810 --> 00:12:22,540
jinsi ya kufanya hesabu.

276
00:12:22,540 --> 00:12:23,460
Mimi najua jinsi ya mpango.

277
00:12:23,460 --> 00:12:26,960
Kufanya ikifungwa 1, recompile, na damn it.

278
00:12:26,960 --> 00:12:31,110
Kwamba ni kweli, kweli kupata
mbali na alama.

279
00:12:31,110 --> 00:12:32,490
>> Basi nini kinaendelea hapa?

280
00:12:32,490 --> 00:12:36,050
Intuitively, misingi ya mawazo yetu
mapema juu ya ukubwa wa aina ya data,

281
00:12:36,050 --> 00:12:38,040
kile ambacho ni lazima kinachotokea hapa
chini ya Hood?

282
00:12:38,040 --> 00:12:39,290
Yeah?

283
00:12:39,290 --> 00:12:43,000

284
00:12:43,000 --> 00:12:43,590
Hasa.

285
00:12:43,590 --> 00:12:46,480
Kama unataka hii usahihi sana, na
hiyo ni heck ya mengi ya usahihi -

286
00:12:46,480 --> 00:12:48,770
20 idadi baada ya uhakika decimal.

287
00:12:48,770 --> 00:12:51,990
Huwezi uwezekano kuwakilisha
holela ya simu isipokuwa kama una

288
00:12:51,990 --> 00:12:52,930
holela ya simu ya bits.

289
00:12:52,930 --> 00:12:54,190
Lakini sisi kufanya hivyo.

290
00:12:54,190 --> 00:12:57,200
Kwa kuelea, sisi tu bits 32.

291
00:12:57,200 --> 00:13:02,260
>> Hivyo kama bits 32 inaweza tu permuted katika
njia - tu kama binadamu wetu juu, hatua

292
00:13:02,260 --> 00:13:05,780
mikono juu au chini - katika idadi mahususi ya
njia, kuna tu idadi finite

293
00:13:05,780 --> 00:13:08,640
ya idadi halisi unaweza kuwakilisha
na wale bits.

294
00:13:08,640 --> 00:13:10,500
Na hivyo kompyuta hatimaye
ni kwenda na

295
00:13:10,500 --> 00:13:11,730
kuanza kukata pembe.

296
00:13:11,730 --> 00:13:15,500
kompyuta inaweza kuficha maelezo wale
kutoka kwetu kwa muda kidogo.

297
00:13:15,500 --> 00:13:18,880
Lakini kama sisi kuanza poking katika idadi
na kuangalia mbali na mbali zaidi katika

298
00:13:18,880 --> 00:13:23,220
trailing idadi katika idadi nzima,
basi sisi kuanza kuona kwamba ni

299
00:13:23,220 --> 00:13:26,480
kweli approximating
wazo la kumi moja.

300
00:13:26,480 --> 00:13:29,860
>> Na hivyo ni zamu nje, kusikitisha, kuna
idadi ya usio wa idadi

301
00:13:29,860 --> 00:13:35,060
hatuwezi kuwakilisha kwa usahihi katika
kompyuta, angalau kwa finite

302
00:13:35,060 --> 00:13:38,030
idadi ya vipande, finite
kiasi cha RAM.

303
00:13:38,030 --> 00:13:41,210
Sasa kwa bahati mbaya, hii wakati mwingine
ina madhara halisi ya dunia.

304
00:13:41,210 --> 00:13:45,980
Kama watu hawana kabisa kufahamu hii
au aina ya kuchukua kwa nafasi ya ukweli

305
00:13:45,980 --> 00:13:48,310
kwamba kompyuta zao tu kufanya kile
wao kuwaambia yake ya kufanya na wala

306
00:13:48,310 --> 00:13:51,430
kuelewa haya ya ndani
uwakilishi wa maelezo -

307
00:13:51,430 --> 00:13:55,290
ambayo, kusema ukweli, katika baadhi ya lugha ni
siri kutoka kwa mtumiaji, tofauti katika C -

308
00:13:55,290 --> 00:13:56,500
baadhi ya mambo mabaya yanaweza kutokea.

309
00:13:56,500 --> 00:13:58,650
>> Na nini Nilidhani tunatarajia kufanya
ni kuchukua hatua nyuma.

310
00:13:58,650 --> 00:14:00,420
Na hii ni kuhusu
nane dakika ya video.

311
00:14:00,420 --> 00:14:04,200
Ni kurushwa hewani miaka michache iliyopita, na inatoa
utambuzi katika kweli nini unaweza kwenda

312
00:14:04,200 --> 00:14:09,290
vibaya wakati wewe chini ya kufahamu haya
aina ya maelezo katika sana wote-pia

313
00:14:09,290 --> 00:14:10,080
ulimwengu halisi.

314
00:14:10,080 --> 00:14:12,965
Kama tunaweza dim taa
kwa dakika chache.

315
00:14:12,965 --> 00:14:14,360
>> SPIKA 1: Sisi sasa kurudi uhandisi

316
00:14:14,360 --> 00:14:17,160
majanga ya Marvels kisasa.

317
00:14:17,160 --> 00:14:18,680
>> Kompyuta -

318
00:14:18,680 --> 00:14:21,340
tumekuwa wote wamekuja kukubali
mara nyingi frustrating matatizo

319
00:14:21,340 --> 00:14:23,170
kwamba kwenda pamoja nao.

320
00:14:23,170 --> 00:14:27,570
Mende, virusi, na glitches programu
ni ndogo bei kulipa kwa ajili ya

321
00:14:27,570 --> 00:14:28,960
urahisi.

322
00:14:28,960 --> 00:14:32,040
Lakini katika high-tech na high-speed
kijeshi na mpango wa nafasi

323
00:14:32,040 --> 00:14:38,650
maombi, tatizo ndogo
yanaweza kujitukuza katika janga.

324
00:14:38,650 --> 00:14:44,480
>> Tarehe 4 Juni, 1996, wanasayansi tayari
kuzindua unmanned Ariane 5 roketi.

325
00:14:44,480 --> 00:14:48,700
Ilikuwa ni kufanya satelaiti kisayansi
iliyoundwa na kuanzisha usahihi jinsi

326
00:14:48,700 --> 00:14:53,250
Dunia shamba magnetic inaingiliana
na upepo wa jua.

327
00:14:53,250 --> 00:14:57,540
roketi iliyojengwa kwa ajili ya Ulaya
Nafasi ya Shirika na lile mbali kutoka yake

328
00:14:57,540 --> 00:14:59,906
kituo katika pwani ya
ya Kifaransa.

329
00:14:59,906 --> 00:15:03,660
>> JACK GANSSLE: Wakati kuhusu 37 sekunde katika
ndege, kwanza niliona

330
00:15:03,660 --> 00:15:04,910
kuna kitu kwenda vibaya.

331
00:15:04,910 --> 00:15:08,130
nozzles walikuwa swiveling katika
njia ya wao kweli lazima si.

332
00:15:08,130 --> 00:15:12,380
Karibu sekunde 40 ndani ya ndege,
wazi gari ilikuwa kwenye matatizo.

333
00:15:12,380 --> 00:15:14,400
Na kwamba wakati wao alifanya
uamuzi kuiharibu.

334
00:15:14,400 --> 00:15:18,520
usalama mbalimbali afisa, na
guts kubwa, taabu ya kifungo,

335
00:15:18,520 --> 00:15:23,900
akapiga juu roketi kabla hawakuweza
kuwa hatari kwa usalama wa umma.

336
00:15:23,900 --> 00:15:27,810
>> SPIKA 1: Hii ilikuwa safari msichana
Ariane ya 5, na uharibifu wake

337
00:15:27,810 --> 00:15:32,020
ulifanyika kwa sababu ya kasoro iliyoingia
katika programu ya roketi.

338
00:15:32,020 --> 00:15:33,980
>> JACK GANSSLE: tatizo juu ya Ariane
ni kwamba kulikuwa na idadi

339
00:15:33,980 --> 00:15:36,390
kwamba required 64 bits kueleza.

340
00:15:36,390 --> 00:15:39,420
Na walitaka kubadilisha
na idadi ya 16-bit.

341
00:15:39,420 --> 00:15:43,130
Wao kudhani kuwa idadi ilikuwa kamwe
kwenda kuwa kubwa sana, ya kwamba zaidi ya

342
00:15:43,130 --> 00:15:46,810
wale maadili katika kidogo 64-
idadi walikuwa zeros.

343
00:15:46,810 --> 00:15:48,270
Walikuwa na makosa.

344
00:15:48,270 --> 00:15:51,380
>> SPIKA 1: kutokuwa na uwezo wa programu moja
mpango kukubali aina ya

345
00:15:51,380 --> 00:15:55,350
idadi yanayotokana na mwingine alikuwa
kwenye mizizi ya kushindwa.

346
00:15:55,350 --> 00:15:59,970
Programu ya maendeleo imekuwa sana
gharama kubwa sehemu ya teknolojia mpya.

347
00:15:59,970 --> 00:16:03,980
Ariane 4 roketi alikuwa sana
mafanikio, hivyo mengi ya programu

348
00:16:03,980 --> 00:16:07,480
kuundwa kwa ajili pia ilikuwa
kutumika katika Ariane 5.

349
00:16:07,480 --> 00:16:11,980
>> PHILIP COYLE: tatizo msingi ilikuwa
kwamba Ariane 5 mara kwa kasi,

350
00:16:11,980 --> 00:16:13,720
kuharakisha kasi zaidi.

351
00:16:13,720 --> 00:16:17,250
Na programu alikuwa na si
waliendelea kwa ajili hiyo.

352
00:16:17,250 --> 00:16:20,770
>> SPIKA 1: uharibifu wa roketi
ilikuwa kubwa kifedha maafa,

353
00:16:20,770 --> 00:16:24,200
wote kutokana na kosa dakika programu.

354
00:16:24,200 --> 00:16:27,820
Lakini hii haikuwa mara ya kwanza data
uongofu matatizo alikuwa wanakumbana kisasa

355
00:16:27,820 --> 00:16:30,620
roketi teknolojia.

356
00:16:30,620 --> 00:16:34,480
>> JACK GANSSLE: Katika mwaka 1991, na kuanza
ya kwanza vita vya Ghuba, Patriot

357
00:16:34,480 --> 00:16:38,610
kombora uzoefu aina sawa
ya tatizo simu uongofu.

358
00:16:38,610 --> 00:16:44,910
Kama matokeo, 28 askari wa Marekani walikuwa
waliuawa na wengine wapatao 100 kujeruhiwa

359
00:16:44,910 --> 00:16:48,600
wakati Patriot, ambayo ilitakiwa
kulinda dhidi ya Scuds zinazoingia,

360
00:16:48,600 --> 00:16:51,630
alishindwa kwa moto kombora.

361
00:16:51,630 --> 00:16:55,110
>> SPIKA 1: Wakati Iraq walivamia Kuwait na
Amerika ilizindua Desert Storm katika

362
00:16:55,110 --> 00:17:00,570
mapema 1991, Patriot kombora betri
walikuwa uliotumika kulinda Saudi Arabia

363
00:17:00,570 --> 00:17:04,760
na Israeli kutoka Scud Iraq
kombora mashambulizi.

364
00:17:04,760 --> 00:17:09,720
Patriot ni Marekani kati-mbalimbali
uso-kwa-hewa mfumo wa viwandani na

365
00:17:09,720 --> 00:17:11,569
Raytheon kampuni.

366
00:17:11,569 --> 00:17:16,410
>> THEODORE POSTOL: ukubwa wa Patriot
interceptor yenyewe ni takribani

367
00:17:16,410 --> 00:17:17,710
20-miguu kwa muda mrefu.

368
00:17:17,710 --> 00:17:20,800
Na ni kizito paundi 2000.

369
00:17:20,800 --> 00:17:22,940
Na hubeba warhead ya juu -

370
00:17:22,940 --> 00:17:24,905
Nadhani ni takribani £ 150.

371
00:17:24,905 --> 00:17:31,030
Na warhead yenyewe ni
high kulipuka ambayo ina

372
00:17:31,030 --> 00:17:33,270
vipande kuzunguka.

373
00:17:33,270 --> 00:17:37,490
casing ya warhead imeundwa
kutenda kama buckshot.

374
00:17:37,490 --> 00:17:40,720
>> SPIKA 1: makombora ni kufanyika wanne
kwa kila kontena na ni kusafirishwa

375
00:17:40,720 --> 00:17:43,050
na Trailer nusu.

376
00:17:43,050 --> 00:17:47,490
>> PHILIP COYLE: Patriot kupambana na kombora
mfumo inakwenda nyuma katika

377
00:17:47,490 --> 00:17:50,710
angalau miaka 20 sasa.

378
00:17:50,710 --> 00:17:54,350
Ni awali ilikuwa imeundwa kama
ulinzi hewa kombora kwa

379
00:17:54,350 --> 00:17:56,190
risasi chini ndege ya adui.

380
00:17:56,190 --> 00:18:02,490
Katika Vita ya Ghuba ya kwanza, wakati kwamba vita
alikuja pamoja, Jeshi alitaka kutumia

381
00:18:02,490 --> 00:18:05,535
kwa risasi chini Scuds, ndege si.

382
00:18:05,535 --> 00:18:09,310
Iraq hewa nguvu haikuwa
sana ya tatizo.

383
00:18:09,310 --> 00:18:12,450
Lakini Jeshi alikuwa na wasiwasi kuhusu Scuds.

384
00:18:12,450 --> 00:18:15,950
Na hivyo walijaribu kuboresha
Patriot.

385
00:18:15,950 --> 00:18:18,750
>> SPIKA 1: Intercepting kombora adui
kusafiri saa mach tano alikuwa

386
00:18:18,750 --> 00:18:20,890
kwenda kuwa changamoto ya kutosha.

387
00:18:20,890 --> 00:18:25,590
Lakini wakati Patriot alikimbizwa katika
huduma, Jeshi hakuwa na ufahamu wa

388
00:18:25,590 --> 00:18:31,710
Iraq muundo kwamba alifanya yao
Scuds karibu vigumu hit.

389
00:18:31,710 --> 00:18:35,240
>> THEODORE POSTOL: Ni nini kilichotokea
Scuds ni kwamba walikuwa

390
00:18:35,240 --> 00:18:36,570
akija katika walikuwa imara.

391
00:18:36,570 --> 00:18:37,532
Walikuwa tikisika.

392
00:18:37,532 --> 00:18:43,220
Sababu ya hayo ni raia wa Iraq, katika
Ili kupata kilomita 600 nje ya

393
00:18:43,220 --> 00:18:47,530
300 wa kilomita-mbalimbali kombora, alichukua
uzito nje ya warhead mbele.

394
00:18:47,530 --> 00:18:49,290
Walitoa warhead nyepesi.

395
00:18:49,290 --> 00:18:53,110
Hivyo sasa Patriot ni kujaribu
kuja kwa Scud.

396
00:18:53,110 --> 00:18:56,470
Na zaidi ya muda, balaa
Wengi wa muda, ingekuwa tu

397
00:18:56,470 --> 00:18:58,730
kuruka na Scud.

398
00:18:58,730 --> 00:19:01,760
>> SPIKA 1: Mara tu mfumo wa Patriot
waendeshaji barabara Patriot amekosa

399
00:19:01,760 --> 00:19:06,690
lengo lake, wao detonated Patriots
warhead ili kuepuka uwezekano

400
00:19:06,690 --> 00:19:10,300
majeruhi kama aliruhusiwa
kuanguka chini.

401
00:19:10,300 --> 00:19:14,540
>> THEODORE POSTOL: Hiyo ilikuwa nini zaidi
watu waliona kama fireballs kubwa angani

402
00:19:14,540 --> 00:19:20,350
na kutoeleweka kama intercepts
Scud ya warheads.

403
00:19:20,350 --> 00:19:23,320
>> SPIKA 1: Ingawa katika anga usiku
Wazalendo alionekana kuwa mafanikio

404
00:19:23,320 --> 00:19:27,530
kuharibu Scuds, saa Dhahran kuna
inaweza kuwa hakuna kosa kuhusu wake

405
00:19:27,530 --> 00:19:29,140
utendaji.

406
00:19:29,140 --> 00:19:34,180
Huko, rada Patriot mfumo wa waliopotea
wimbo wa Scud zinazoingia na kamwe

407
00:19:34,180 --> 00:19:36,380
ilizinduliwa kutokana na kasoro programu.

408
00:19:36,380 --> 00:19:39,890

409
00:19:39,890 --> 00:19:42,700
>> Ni mara ya kwanza aligundua Israel ambao
kwamba tena mfumo

410
00:19:42,700 --> 00:19:48,020
ilikuwa juu, tofauti kubwa wakati
akawa kutokana na saa

411
00:19:48,020 --> 00:19:50,470
iliyoingia katika mfumo wa kompyuta ya.

412
00:19:50,470 --> 00:19:54,640
>> JACK GANSSLE: Kuhusu wiki mbili kabla ya
janga katika Dhahran, Israel

413
00:19:54,640 --> 00:19:58,440
taarifa ya Wizara ya Ulinzi
kwamba mfumo alikuwa kupoteza muda.

414
00:19:58,440 --> 00:20:01,280
Baada ya masaa nane ya kukimbia,
waligundua kwamba mfumo ni

415
00:20:01,280 --> 00:20:03,530
kuwa unaonekana chini sahihi.

416
00:20:03,530 --> 00:20:07,710
Wizara ya Ulinzi alijibu kwa
kuwaambia yote ya betri Patriot

417
00:20:07,710 --> 00:20:10,500
na si kuondoka mifumo
juu kwa muda mrefu.

418
00:20:10,500 --> 00:20:12,430
Wao kamwe alisema nini kwa muda mrefu ilikuwa.

419
00:20:12,430 --> 00:20:13,330
Masaa nane?

420
00:20:13,330 --> 00:20:13,810
Masaa 10?

421
00:20:13,810 --> 00:20:14,990
1000 masaa?

422
00:20:14,990 --> 00:20:17,150
Hakuna aliyejua.

423
00:20:17,150 --> 00:20:20,220
>> SPIKA 1: betri Patriot stationed
katika kambi ya saa Dhahran

424
00:20:20,220 --> 00:20:24,660
na ndani yake saa kiujanja alikuwa
juu zaidi ya 100 masaa ya usiku wa

425
00:20:24,660 --> 00:20:27,470
Februari 25.

426
00:20:27,470 --> 00:20:31,770
>> JACK GANSSLE: Ni msisimko wakati wa
usahihi wa juu ya kumi ya pili.

427
00:20:31,770 --> 00:20:34,480
Sasa, sehemu ya kumi ya pili ni
kuvutia idadi sababu haiwezi kuwa

428
00:20:34,480 --> 00:20:39,940
walionyesha katika binary hasa, ambayo ina maana
haiwezi kuwa walionyesha hasa katika

429
00:20:39,940 --> 00:20:42,500
yoyote ya kisasa ya digital kompyuta.

430
00:20:42,500 --> 00:20:46,920
Ni vigumu kuamini, lakini
kutumia hii kama mfano.

431
00:20:46,920 --> 00:20:49,000
Hebu kuchukua namba moja ya tatu.

432
00:20:49,000 --> 00:20:53,150
Theluthi moja hawezi kuwa walionyesha
katika decimal hasa.

433
00:20:53,150 --> 00:20:57,500
Moja ya tatu ni 0.333 kwenda
juu kwa infinity.

434
00:20:57,500 --> 00:21:02,270
Hakuna njia ya kufanya hivyo na
kabisa usahihi katika decimal.

435
00:21:02,270 --> 00:21:05,370
Hiyo hasa aina moja ya tatizo
yaliyotokea katika Patriot.

436
00:21:05,370 --> 00:21:09,880
tena mfumo wa mbio,
mbaya kosa wakati akawa.

437
00:21:09,880 --> 00:21:13,840
>> SPIKA 1: Baada ya 100 masaa ya kazi,
makosa katika wakati ilikuwa tu

438
00:21:13,840 --> 00:21:16,140
theluthi moja ya pili.

439
00:21:16,140 --> 00:21:20,800
Lakini katika suala la kulenga kombora
kusafiri saa mach tano, ni matokeo ya

440
00:21:20,800 --> 00:21:24,410
makosa ya kufuatilia ya zaidi ya mita 600.

441
00:21:24,410 --> 00:21:27,670
Itakuwa kosa mbaya kwa
askari katika Dhahran.

442
00:21:27,670 --> 00:21:33,450
>> THEODORE POSTOL: Kilichotokea ni
Uzinduzi Scud ilikuwa wanaona na mapema

443
00:21:33,450 --> 00:21:34,280
onyo satelaiti.

444
00:21:34,280 --> 00:21:38,550
Na walijua kuwa Scud alikuwa anakuja
katika mwelekeo wao kwa ujumla.

445
00:21:38,550 --> 00:21:41,000
Hawakujua ambapo ilikuwa ijayo.

446
00:21:41,000 --> 00:21:43,900
>> SPIKA 1: Ilikuwa sasa hadi rada
sehemu ya mfumo Patriot

447
00:21:43,900 --> 00:21:48,910
kutetea Dhahran na Machapisho na kuweka
wimbo wa kombora zinazoingia adui.

448
00:21:48,910 --> 00:21:50,580
>> JACK GANSSLE: rada
alikuwa smart sana.

449
00:21:50,580 --> 00:21:53,770
Ingekuwa kweli kufuatilia nafasi ya
Scud na kisha kutabiri ambapo ni

450
00:21:53,770 --> 00:21:57,160
pengine itakuwa wakati ujao
rada alimtuma mapigo nje.

451
00:21:57,160 --> 00:21:58,870
Kwamba aliitwa lango mbalimbali.

452
00:21:58,870 --> 00:22:04,020
>> THEODORE POSTOL: Kisha mara moja Patriot
anaamua muda wa kutosha kupita kwenda

453
00:22:04,020 --> 00:22:09,420
nyuma na kuangalia eneo ijayo kwa ajili ya
hii kitu wanaona, unaendelea nyuma.

454
00:22:09,420 --> 00:22:14,450
Hivyo wakati akarudi vibaya
mahali, basi anaona hakuna kitu.

455
00:22:14,450 --> 00:22:18,200
Na anaamua kwamba kulikuwa hakuna kitu chochote,
ilikuwa kugundua uongo, na

456
00:22:18,200 --> 00:22:19,680
matone ya kufuatilia.

457
00:22:19,680 --> 00:22:22,970
>> SPIKA 1: Scud zinazoingia kutoweka
kutoka screen rada, na

458
00:22:22,970 --> 00:22:26,050
sekunde baadaye slammed
Paulo ndani ya ngome.

459
00:22:26,050 --> 00:22:31,950
Scud kuuawa 28 na mara moja ya mwisho
fired wakati wa Vita ya Ghuba ya kwanza.

460
00:22:31,950 --> 00:22:37,700
Kusikitisha, programu updated aliwasili
saa Dhahran siku iliyofuata.

461
00:22:37,700 --> 00:22:41,800
flaw programu amekuwa fasta,
kufunga sura moja katika wasiwasi

462
00:22:41,800 --> 00:22:43,690
historia ya kombora Patriot.

463
00:22:43,690 --> 00:22:46,780

464
00:22:46,780 --> 00:22:50,710
>> Mzalendo ni kweli kifupi
kwa ajili ya kufuatilia Phased Array

465
00:22:50,710 --> 00:22:51,960
Kukatiza ya Lugha.

466
00:22:51,960 --> 00:22:54,650

467
00:22:54,650 --> 00:23:00,840
>> DAVID J Malan: zote haki, hivyo
yanayotisha mfano, kuwa na uhakika.

468
00:23:00,840 --> 00:23:03,430
Na kwa bahati nzuri, hizi ngazi ya chini
mende ni si kitu ambacho tutaweza

469
00:23:03,430 --> 00:23:06,220
kawaida kuwa na kufahamu, hakika
si kwa baadhi ya yetu ya

470
00:23:06,220 --> 00:23:07,360
mwanzo wa mipango.

471
00:23:07,360 --> 00:23:10,450
Badala yake, zaidi ya mende utasikia
kukutana itakuwa mantiki katika asili,

472
00:23:10,450 --> 00:23:12,900
kisintaksia katika asili ambapo
kanuni tu haina kazi ya haki.

473
00:23:12,900 --> 00:23:14,140
Na unajua ni pretty kufunga.

474
00:23:14,140 --> 00:23:16,850
>> Lakini hasa wakati sisi kupata
mwisho wa muhula, ni kwenda

475
00:23:16,850 --> 00:23:20,620
kuwa zaidi na zaidi ya uwezekano wa
kweli kufikiri kwa bidii juu ya kubuni

476
00:23:20,620 --> 00:23:22,960
ya mipango yako na msingi
uwakilishi

477
00:23:22,960 --> 00:23:24,520
huko, pia, ya data.

478
00:23:24,520 --> 00:23:28,010
Kwa mfano, tutaweza kuanzisha MySQL,
ambayo ni maarufu injini database

479
00:23:28,010 --> 00:23:30,850
kwamba unaweza kutumia na tovuti ya
kuhifadhi data juu ya mwisho ya nyuma.

480
00:23:30,850 --> 00:23:34,630
Na itabidi kuanza kuamua katika
mwisho wa muhula sio tu kile

481
00:23:34,630 --> 00:23:38,790
aina ya data pamoja na mistari haya ya kutumia
lakini hasa jinsi wengi bits kutumia,

482
00:23:38,790 --> 00:23:42,740
kama au unataka kuhifadhi tarehe
kama tarehe na nyakati kama nyakati, na pia

483
00:23:42,740 --> 00:23:46,890
mambo kama jinsi kubwa unataka
Vitambulisho vya kipekee kwa kuwa, kusema, watumiaji

484
00:23:46,890 --> 00:23:47,680
katika orodha yako.

485
00:23:47,680 --> 00:23:51,210
>> Kwa kweli, kama baadhi yenu alikuwa na
Picha za hesabu kwa muda kabisa,

486
00:23:51,210 --> 00:23:53,680
na wewe kujua jinsi ya kupata
na Mtumiaji ID yako -

487
00:23:53,680 --> 00:23:57,930
ambayo wakati mwingine inaonyesha juu katika yako
maelezo mafupi ya URL ya isipokuwa umechagua

488
00:23:57,930 --> 00:24:02,070
utani kwa ajili ya URL, au kama wewe wameweza
kutumika Facebook Grafu API,

489
00:24:02,070 --> 00:24:05,510
hadharani API na ambayo
unaweza kuuliza Facebook kwa takwimu ghafi -

490
00:24:05,510 --> 00:24:07,580
unaweza kuona nini ID yako numeric ni.

491
00:24:07,580 --> 00:24:10,880
Na baadhi ya miaka iliyopita, Facebook kimsingi
alikuwa na mabadiliko ya kutoka kutumia

492
00:24:10,880 --> 00:24:15,980
sawa ya ints kwa kutumia muda mrefu
muda mrefu kwa sababu baada ya muda kama watumiaji kuja

493
00:24:15,980 --> 00:24:19,780
na kwenda na na kujenga kura ya akaunti
bandia akaunti, hata wao kwa urahisi sana

494
00:24:19,780 --> 00:24:24,630
walikuwa na uwezo wa kutolea nje kitu kama 4
bilioni iwezekanavyo thamani kama int.

495
00:24:24,630 --> 00:24:28,340
>> Hivyo zaidi juu ya aina wale wa masuala ya
chini ya barabara, kama vile.

496
00:24:28,340 --> 00:24:30,750
Haki ya wote, hivyo kwamba alikuwa akitoa.

497
00:24:30,750 --> 00:24:31,670
Hiyo ilikuwa ni kutokuwa sahihi.

498
00:24:31,670 --> 00:24:32,730
michache ya matangazo ya haraka.

499
00:24:32,730 --> 00:24:35,710
Hivyo sehemu rasmi kuanza hii kuja
Jumapili, Jumatatu, Jumanne.

500
00:24:35,710 --> 00:24:39,080
Utasikia kupitia barua pepe baadaye wiki hii
kama sehemu ya kazi yako.

501
00:24:39,080 --> 00:24:42,570
Na itabidi hapa pia katika hatua hiyo jinsi
na mabadiliko ya sehemu yako kama yako

502
00:24:42,570 --> 00:24:45,660
ratiba ya sasa imebadilika au yako
faraja ngazi sasa imebadilika.

503
00:24:45,660 --> 00:24:49,380
Wakati huo huo P-seti moja na moja ni hacker
kutokana hii Alhamisi na chaguo

504
00:24:49,380 --> 00:24:52,450
kupanua kwamba tarehe ya mwisho kwa
specifikationer hadi Ijumaa

505
00:24:52,450 --> 00:24:53,830
katika njia ya kawaida.

506
00:24:53,830 --> 00:24:57,500
>> Kutambua kwamba pamoja na tatizo
kuweka specifikationer ni maelekezo ya

507
00:24:57,500 --> 00:25:02,770
jinsi ya kutumia appliance CS50, kufanya,
kama vile baadhi CS50 maalum zana

508
00:25:02,770 --> 00:25:06,540
kama style 50, ambayo inaweza kutoa
na maoni juu ya dynamically

509
00:25:06,540 --> 00:25:10,230
ubora wa kanuni style yako na pia
kuangalia 50, ambayo inaweza kutoa kwa

510
00:25:10,230 --> 00:25:13,160
nguvu maoni kama yako
kanuni ya usahihi.

511
00:25:13,160 --> 00:25:16,850
Kusamehe kwamba bado tuko Board
nje kinks wachache na hundi 50.

512
00:25:16,850 --> 00:25:21,490
machache ya wanafunzi wenzako ambao hawakuwa kuanza
kuzunguka 4:00 usiku wa Ijumaa wakati

513
00:25:21,490 --> 00:25:25,130
spec akapanda niliona tangu hapo
mende chache kwamba sisi ni kazi

514
00:25:25,130 --> 00:25:29,010
kupitia, na msamaha kwa mtu yeyote ambaye
ina uzoefu frustrations visivyofaa.

515
00:25:29,010 --> 00:25:30,340
kosa ni yangu.

516
00:25:30,340 --> 00:25:34,080
Lakini tutaweza kufuatilia CS50
kujadili wakati kwamba ni kutatuliwa.

517
00:25:34,080 --> 00:25:35,700
>> Hivyo neno juu ya alama wenyewe.

518
00:25:35,700 --> 00:25:38,990
Hivyo utakuwa wiki moja au mbili kabla ya
kuanza kupata maoni juu ya seti tatizo

519
00:25:38,990 --> 00:25:40,640
kwa sababu wewe bado hatuna
wenzake kufundisha.

520
00:25:40,640 --> 00:25:44,510
Na hata basi, sisi kuanza kutathmini
Tatizo C seti kabla ya sisi

521
00:25:44,510 --> 00:25:46,970
kurudi nyuma na kutathmini mwanzo hivyo
kwamba kupata zaidi husika

522
00:25:46,970 --> 00:25:48,150
maoni kwa haraka zaidi.

523
00:25:48,150 --> 00:25:51,870
Lakini kwa ujumla kwa mtaala, CS50
seti tatizo ni tathmini pamoja

524
00:25:51,870 --> 00:25:53,580
kufuatia shoka nne -

525
00:25:53,580 --> 00:25:55,760
upeo, usahihi, kubuni, na style.

526
00:25:55,760 --> 00:25:59,210
>> Wigo ni kwenda kuwa idadi kawaida
kati ya sifuri na tano kwamba

527
00:25:59,210 --> 00:26:01,830
Ukamataji wa kiasi gani cha
kipande kwamba wewe wakawauma mbali.

528
00:26:01,830 --> 00:26:03,750
Kwa kawaida, unataka hii kuwa tano.

529
00:26:03,750 --> 00:26:05,300
Wewe angalau alijaribu kila kitu.

530
00:26:05,300 --> 00:26:09,330
Na taarifa ni sababu multiplicative
ili kufanya sehemu tu ya

531
00:26:09,330 --> 00:26:12,520
tatizo kuweka si mkakati bora.

532
00:26:12,520 --> 00:26:15,610
>> Wakati huo huo, wazi zaidi ni
umuhimu wa usahihi -

533
00:26:15,610 --> 00:26:18,620
tu ni mpango wako sahihi na
kuheshimu na vipimo?

534
00:26:18,620 --> 00:26:21,510
Hii ni mizigo kwa makusudi zaidi
sana kuliko wengine wawili na shoka

535
00:26:21,510 --> 00:26:24,450
Sababu ya tatu kwa sababu tunatambua
kwamba kwa kawaida wewe ni kwenda kutumia

536
00:26:24,450 --> 00:26:28,600
mengi zaidi wakati Chasing chini baadhi ya mende,
kupata kanuni yako ya kufanya kazi, basi

537
00:26:28,600 --> 00:26:31,540
ni indenting yake na kuchagua
sahihi kutofautiana majina na

538
00:26:31,540 --> 00:26:33,800
kama, ambayo ni ya mwisho mwingine
ya wigo wa style.

539
00:26:33,800 --> 00:26:36,160
>> Hiyo si kusema style si
muhimu, na tutaweza kuhubiri juu ya

540
00:26:36,160 --> 00:26:37,920
wakati wote katika mihadhara na katika sehemu.

541
00:26:37,920 --> 00:26:40,520
Sinema inahusu aesthetics
ya maadili yako.

542
00:26:40,520 --> 00:26:43,980
Je waliochaguliwa vizuri aitwaye vigezo
kwamba ni mfupi lakini kwa kiasi fulani

543
00:26:43,980 --> 00:26:44,680
maelezo?

544
00:26:44,680 --> 00:26:47,840
Ni kanuni yako indented kama ve kuonekana katika
hotuba na kwa njia thabiti

545
00:26:47,840 --> 00:26:49,070
kwa mtindo wa 50?

546
00:26:49,070 --> 00:26:51,220
>> Mwisho ni haki ya kubuni
pale katikati.

547
00:26:51,220 --> 00:26:54,090
Kubuni ni moja vigumu kuweka
kidole juu kwa sababu ni mengi zaidi

548
00:26:54,090 --> 00:26:55,000
subjective.

549
00:26:55,000 --> 00:26:58,610
Lakini ni labda muhimu zaidi ya
shoka tatu katika suala la ufundishaji

550
00:26:58,610 --> 00:27:02,050
thamani ya zaidi ya muda na kwamba hii itakuwa
fursa ya kufundisha wenzake kwa

551
00:27:02,050 --> 00:27:04,110
kutoa kwa maoni ya ubora.

552
00:27:04,110 --> 00:27:08,100
Hakika, katika CS50 ingawa sisi kufanya
haya formula na alama, mwishoni

553
00:27:08,100 --> 00:27:11,350
ya siku hizi ni kwa makusudi
ndogo sana ndoo - kumweka maadili

554
00:27:11,350 --> 00:27:13,460
kati ya sifuri na tatu
na sifuri na tano.

555
00:27:13,460 --> 00:27:17,800
Sisi si kujaribu kuteka mistari magumu
kati ya tatizo seti au kati ya

556
00:27:17,800 --> 00:27:21,490
wanafunzi lakini badala ya kuzingatia kama vile
tunaweza juu ya ubora, longhand

557
00:27:21,490 --> 00:27:25,490
maoni, ama typed au matusi kutoka
ufundishaji wako hasa wenzetu,

558
00:27:25,490 --> 00:27:27,050
utasikia kupata kujua vizuri kabisa.

559
00:27:27,050 --> 00:27:32,340
>> Lakini kwa ujumla, wale ni uzito
kwamba shoka mbalimbali watapata.

560
00:27:32,340 --> 00:27:35,480
Wakati huo huo, pia, ni thamani ya kushika katika
akilini kwamba ni lazima si kudhani kwamba

561
00:27:35,480 --> 00:27:38,870
tatu kati ya tano ni 60% na
Basi takribani kushindwa.

562
00:27:38,870 --> 00:27:41,410
Tatu ni makusudi maana ya kuwa
aina ya katikati ya barabara nzuri.

563
00:27:41,410 --> 00:27:43,480
Kama wewe ni kupata threes katika
mwanzo wa muhula, hiyo ni

564
00:27:43,480 --> 00:27:46,340
kweli maana ya kuwa nzuri
mahali ya kuanza.

565
00:27:46,340 --> 00:27:50,510
Kama wewe ni kupata wawili-wawili maonyesho,, kuna
dhahiri baadhi ya kazi kwa kulipa kidogo

566
00:27:50,510 --> 00:27:53,250
kipaumbele zaidi, kuchukua faida
ya sehemu na masaa ya ofisi.

567
00:27:53,250 --> 00:27:54,590
>> Kama wewe ni kupata fours
na umri wa miaka mitano, kubwa.

568
00:27:54,590 --> 00:27:57,430
Lakini kwa kweli, tunatarajia kuona trajectories
kati ya wanafunzi - sana

569
00:27:57,430 --> 00:28:00,575
mtu mmoja mmoja kwa kila mwanafunzi, lakini kuanzia
muhula hapa katika aina ya

570
00:28:00,575 --> 00:28:04,100
wawili mbalimbali tatu lakini kuishia
hapa juu katika mbalimbali 4-5.

571
00:28:04,100 --> 00:28:05,440
Hiyo ni nini sisi ni kweli kutafuta.

572
00:28:05,440 --> 00:28:09,590
Na hatuna kukumbuka kwamba delta
wewe maonyesho kati ya wiki sifuri na wiki

573
00:28:09,590 --> 00:28:12,170
12 wakati mimi nina kufanya darasa.

574
00:28:12,170 --> 00:28:16,380
Haijalishi kwetu kabisa jinsi
wewe haki mwanzoni kama yako

575
00:28:16,380 --> 00:28:19,330
trajectory ni kweli
zaidi na nguvu.

576
00:28:19,330 --> 00:28:24,000
>> Uaminifu kitaaluma - hivyo basi mimi kuweka juu yangu
mbaya zaidi sauti kwa muda tu.

577
00:28:24,000 --> 00:28:28,510
Hivyo bila shaka hii ina tofauti ya
kupeleka wanafunzi zaidi kuliko nyingine yoyote

578
00:28:28,510 --> 00:28:30,950
katika historia ya bodi ad, naamini.

579
00:28:30,950 --> 00:28:34,220
Tuna aina ya kuhesabu waliopotea katika hii
uhakika wa jinsi mara nyingi hii hutokea.

580
00:28:34,220 --> 00:28:37,090
Na si kwamba kwa sababu ya wanafunzi katika 50
ni yoyote zaidi kuliko wao mwaminifu

581
00:28:37,090 --> 00:28:38,690
classmates mahali pengine.

582
00:28:38,690 --> 00:28:42,800
Lakini kutambua, pia kwamba, sisi ni nzuri sana
katika kuchunguza jambo la aina hii.

583
00:28:42,800 --> 00:28:45,920
>> Na kwamba ni faida ya kuwa
sayansi ya kompyuta ya darasa ana kwa kuwa sisi

584
00:28:45,920 --> 00:28:49,110
unaweza na hatuwezi kulinganisha wanafunzi wote
tatizo seti jozi-busara dhidi ya kila

585
00:28:49,110 --> 00:28:51,470
mengine, si tu mwaka huu
lakini wote kabla ya miaka.

586
00:28:51,470 --> 00:28:55,080
Tuna uwezo, kama wanafunzi katika
darasani, kwa Google na kutafuta kanuni ya

587
00:28:55,080 --> 00:28:57,440
katika maeneo kama github na
majadiliano ya vikao.

588
00:28:57,440 --> 00:29:00,840
Kuna kabisa ufumbuzi wa CS50 ya
p-seti yaliyo karibu huko.

589
00:29:00,840 --> 00:29:02,710
Lakini kama unaweza kupata yao,
tunaweza kupata yao.

590
00:29:02,710 --> 00:29:07,130
Na yote haya ni mengi sana automatiska
na rahisi na kusikitisha kwa sisi kupata.

591
00:29:07,130 --> 00:29:10,990
>> Lakini nataka kusisitiza, pia kwamba
kozi ya kitaaluma uaminifu sera ni

592
00:29:10,990 --> 00:29:13,960
sana maana ya kuwa mengi sana
kinyume cha roho hiyo.

593
00:29:13,960 --> 00:29:17,506
Hakika, mwaka huu tumekuwa rephrased mambo
katika mtaala kuwa hii, dot

594
00:29:17,506 --> 00:29:19,790
dot dot, kwa undani zaidi
katika mtaala.

595
00:29:19,790 --> 00:29:22,860
Lakini mada kuu katika kozi
kweli ni kuwa na busara.

596
00:29:22,860 --> 00:29:26,160
Tunatambua kwamba huko ni muhimu
kiasi cha ufundishaji

597
00:29:26,160 --> 00:29:30,550
thamani ya kushirikiana, kwa kiasi fulani,
na wanafunzi, ambapo wewe

598
00:29:30,550 --> 00:29:33,700
mbili au tatu au wewe zaidi ni
wamesimama katika bodi nyeupe

599
00:29:33,700 --> 00:29:35,670
whiteboarding, hivyo
kusema, mawazo yako -

600
00:29:35,670 --> 00:29:39,480
kuandika nje pseudocode katika picha,
diagramming kile lazima Mario kuwa kama

601
00:29:39,480 --> 00:29:41,350
ungekuwa na kuandika ni ya kwanza
katika pseudocode.

602
00:29:41,350 --> 00:29:43,240
Kile lazima algorithm tamaa -

603
00:29:43,240 --> 00:29:46,100
jinsi lazima ni kuishi kwa
tatizo seti moja?

604
00:29:46,100 --> 00:29:50,440
>> Na hivyo kutambua kwamba tabia
kwamba sisi moyo sana

605
00:29:50,440 --> 00:29:51,470
sana pamoja na mistari hayo.

606
00:29:51,470 --> 00:29:53,890
Na katika mtaala, utaona
nzima rundo la risasi chini ya

607
00:29:53,890 --> 00:29:57,740
kuridhisha jamii na si ya kuridhisha
jamii ambayo inatusaidia kusaidia

608
00:29:57,740 --> 00:30:00,740
wewe wrap akili yako karibu ambapo
hatuwezi kuteka kuwa mstari.

609
00:30:00,740 --> 00:30:04,340
Na kwa ujumla, utawala bora wa thumb
ni kwamba kama wewe wanajitahidi kutatua

610
00:30:04,340 --> 00:30:07,990
baadhi ya mdudu na rafiki yako au classmate
ni kukaa karibu na wewe, ni

611
00:30:07,990 --> 00:30:11,530
busara kwa wewe kuonyesha kwake
kanuni yako na kusema, hey, unaweza kusaidia

612
00:30:11,530 --> 00:30:13,700
mimi kufikiri nini kinaendelea vibaya hapa?

613
00:30:13,700 --> 00:30:17,110
>> Sisi si kawaida kukumbatia
upande wa pili.

614
00:30:17,110 --> 00:30:20,730
Ni si jibu sahihi kwa ajili yako
rafiki au classmate hapa kusema, oh,

615
00:30:20,730 --> 00:30:22,510
kuangalia tu katika mgodi na takwimu
ni nje na kwamba.

616
00:30:22,510 --> 00:30:24,400
Hiyo ni aina ya maana.

617
00:30:24,400 --> 00:30:27,750
Lakini kuwa na mtu mwingine, mwingine ubongo,
mwingine jozi ya macho kuangalia

618
00:30:27,750 --> 00:30:31,620
screen yako au kuangalia code yako
na kusema, ni wewe uhakika unataka

619
00:30:31,620 --> 00:30:32,760
kuwa kitanzi hapa?

620
00:30:32,760 --> 00:30:34,800
Au wewe ni uhakika unataka
kwamba semicolon hapa?

621
00:30:34,800 --> 00:30:37,090
Au oh, kwamba ujumbe wa kosa maana hii.

622
00:30:37,090 --> 00:30:39,580
Wale ni nzuri sana na
moyo tabia.

623
00:30:39,580 --> 00:30:44,010
>> kesi ambayo nilikuwa akidokeza
mapema jipu chini wakati wanafunzi ni

624
00:30:44,010 --> 00:30:47,350
usiku na kufanya hukumu maskini
maamuzi na emailing kanuni zao kwa

625
00:30:47,350 --> 00:30:50,130
mtu mwingine au kusema tu,
hapa, ni katika Dropbox au

626
00:30:50,130 --> 00:30:51,610
Googling marehemu wakati wa usiku.

627
00:30:51,610 --> 00:30:54,880
Na hivyo napenda kuwatia moyo na kuombaomba ya wewe,
Ukiwa na wale kuepukika

628
00:30:54,880 --> 00:30:58,450
wakati wa dhiki, wewe ni bumping up
dhidi ya tarehe ya mwisho, wewe huna marehemu

629
00:30:58,450 --> 00:31:01,490
siku tangu ni tayari Ijumaa saa kwamba
uhakika, email vichwa shaka au

630
00:31:01,490 --> 00:31:02,330
mwenyewe moja kwa moja.

631
00:31:02,330 --> 00:31:04,790
Kusema, kusikiliza, mimi nina katika wangu
kuvunja uhakika hapa.

632
00:31:04,790 --> 00:31:06,660
Hebu kuwa na mazungumzo
na takwimu ni nje.

633
00:31:06,660 --> 00:31:10,400
Kutegemea mtandao au nyingine si
tabia nzuri ni kamwe

634
00:31:10,400 --> 00:31:13,070
ufumbuzi, na pia wengi wako
classmates tena hapa

635
00:31:13,070 --> 00:31:15,150
chuo kwa sababu ya hukumu kuwa maskini.

636
00:31:15,150 --> 00:31:17,840
Lakini ni rahisi sana skirt kuwa mstari.

637
00:31:17,840 --> 00:31:22,950
>> Na hapa ni picha kidogo na moyo
ninyi kutoka Reddit ili sasa

638
00:31:22,950 --> 00:31:25,720
kila kitu kitakuwa sawa.

639
00:31:25,720 --> 00:31:30,210
>> Hivyo kurejea haraka, basi,
ya ambapo sisi kushoto mbali.

640
00:31:30,210 --> 00:31:33,690
Hivyo wiki iliyopita, kukumbuka kuwa sisi kuanzisha
masharti, si katika Scratch

641
00:31:33,690 --> 00:31:34,880
lakini katika C wakati huu.

642
00:31:34,880 --> 00:31:38,300
Na kulikuwa na baadhi syntax mpya lakini
kweli hakuna mawazo mapya per se.

643
00:31:38,300 --> 00:31:42,630
Tulikuwa na maneno Boolean kwamba tunaweza
au pamoja na wima mbili

644
00:31:42,630 --> 00:31:46,490
baa au na pamoja na mbili
ampersands, akisema kwamba wote wa kushoto

645
00:31:46,490 --> 00:31:49,990
na kulia lazima kuwa kweli
kwa hili nitafanya.

646
00:31:49,990 --> 00:31:53,150
Kisha sisi alikuwa swichi, ambayo sisi inaonekana
saa ufupi, lakini mimi kupendekeza ni kweli

647
00:31:53,150 --> 00:31:56,830
tu tofauti syntax kwa ajili ya kufikia
huo aina ya lengo kama unajua katika

648
00:31:56,830 --> 00:31:59,270
kuendeleza kile kesi yako
ni kwenda kuwa.

649
00:31:59,270 --> 00:32:00,160
>> Tuliangalia matanzi.

650
00:32:00,160 --> 00:32:03,340
kwa kitanzi ni labda ya kawaida,
au angalau mmoja kwamba watu

651
00:32:03,340 --> 00:32:05,330
kawaida kufikia kwa ajili ya kisilika.

652
00:32:05,330 --> 00:32:08,240
Hata ingawa inaonekana kidogo fumbo,
utaona wengi, mifano mingi ya hii

653
00:32:08,240 --> 00:32:11,590
kabla ya muda mrefu, kama una
tayari mwishoni mwa wiki iliyopita.

654
00:32:11,590 --> 00:32:14,280
Wakati tanzi unaweza vile vile
kufanikisha jambo hilo.

655
00:32:14,280 --> 00:32:17,550
Lakini kama unataka kufanya lolote incrementation
au kuongezea ya

656
00:32:17,550 --> 00:32:20,230
kutofautiana wa maadili, una
kufanya hivyo zaidi kuliko manually

657
00:32:20,230 --> 00:32:22,440
kwa kitanzi kabla inaruhusu.

658
00:32:22,440 --> 00:32:25,310
Na kisha kuna kitanzi do-wakati,
ambayo inaruhusu yetu kufanya kitu fulani katika

659
00:32:25,310 --> 00:32:28,460
angalau mara moja kwa wakati kitu
mwingine ni kweli.

660
00:32:28,460 --> 00:32:31,550
Na hii ni nzuri hasa kwa
mipango au kwa ajili ya michezo ambapo unataka

661
00:32:31,550 --> 00:32:33,810
kuchochea mtumiaji kwa ajili ya kitu
angalau mara moja.

662
00:32:33,810 --> 00:32:37,110
Na kisha kama yeye au yeye hana kushirikiana,
unaweza kutaka kufanya hivyo

663
00:32:37,110 --> 00:32:38,420
tena na tena.

664
00:32:38,420 --> 00:32:41,270
>> Na vigezo, wakati huo huo, tulikuwa na mistari
ya maadili kama hii, ambayo inaweza

665
00:32:41,270 --> 00:32:41,950
kuwa ya mistari miwili.

666
00:32:41,950 --> 00:32:44,830
Unaweza kutangaza int kuitwa
counter, semicolon.

667
00:32:44,830 --> 00:32:47,660
Au unaweza tu kutangaza na
kufafanua, hivyo kusema.

668
00:32:47,660 --> 00:32:49,950
Kuwapa thamani kwa wakati mmoja.

669
00:32:49,950 --> 00:32:51,890
>> Na kisha mwisho, sisi aliyesema
juu ya kazi.

670
00:32:51,890 --> 00:32:54,270
Na hii ilikuwa mfano mzuri katika
maana kwamba unaeleza

671
00:32:54,270 --> 00:32:55,840
aina mbili ya kazi.

672
00:32:55,840 --> 00:32:59,030
Moja ni GetString (), ambayo, tena,
anapata kamba kutoka mtumiaji.

673
00:32:59,030 --> 00:33:02,040
Lakini GetString () ni aina ya kuvutia,
hivyo mbali kama tumekuwa kutumika,

674
00:33:02,040 --> 00:33:05,620
kwa sababu tumekuwa daima kutumika kwa
kitu upande wa mkono wa kushoto wa

675
00:33:05,620 --> 00:33:06,600
sawa ishara.

676
00:33:06,600 --> 00:33:09,830
Hiyo ni kusema kwamba GetString ()
anarudi thamani.

677
00:33:09,830 --> 00:33:11,970
Kuirudisha, bila shaka, kamba.

678
00:33:11,970 --> 00:33:15,130
Halafu kwa upande wa mkono wa kushoto, tuko
tu kuokoa kwamba kamba ndani ya

679
00:33:15,130 --> 00:33:16,580
variable kuitwa jina.

680
00:33:16,580 --> 00:33:21,100
>> Hii ni tofauti, katika hisia, kutoka
printf sababu printf, angalau katika yetu

681
00:33:21,100 --> 00:33:23,540
matumizi ya hapa, haina kurudi kitu.

682
00:33:23,540 --> 00:33:24,960
Kama kando, haina kurudi kitu.

683
00:33:24,960 --> 00:33:26,380
Sisi tu hawajali ni nini.

684
00:33:26,380 --> 00:33:29,090
Lakini haina na nini
aitwaye athari upande.

685
00:33:29,090 --> 00:33:31,840
Na nini ni kwamba athari upande katika kila
kesi tumeona hivi sasa?

686
00:33:31,840 --> 00:33:34,720
Je printf kufanya?

687
00:33:34,720 --> 00:33:37,780
Ni kitu prints kwa screen,
maonyesho ya maandishi au namba au kitu

688
00:33:37,780 --> 00:33:38,380
kwenye screen.

689
00:33:38,380 --> 00:33:41,170
Na kwamba tu kuchukuliwa athari upande
kwa sababu si kweli kuwapatia

690
00:33:41,170 --> 00:33:41,900
ni kuunga kwangu.

691
00:33:41,900 --> 00:33:44,770
Siyo jibu ndani ya
sanduku nyeusi kwamba naweza basi

692
00:33:44,770 --> 00:33:46,130
kufikia katika na kunyakua.

693
00:33:46,130 --> 00:33:49,160
Ni tu kufanya hivyo juu yake mwenyewe, kiasi
kama Colton ilikuwa imeingia kwenye hii

694
00:33:49,160 --> 00:33:52,560
nyeusi sanduku wiki iliyopita, na yeye kwa namna fulani
magically ilikuwa kuchora kwenye bodi

695
00:33:52,560 --> 00:33:54,500
bila mimi kweli kushiriki.

696
00:33:54,500 --> 00:33:55,560
Hiyo itakuwa na athari upande.

697
00:33:55,560 --> 00:33:59,100
Lakini kama mimi kwa kweli alikuwa na kufikia nyuma katika
hapa na kusema, oh, hapa ni kamba

698
00:33:59,100 --> 00:34:02,040
kutoka kwa mtumiaji, kwamba ingekuwa
kuwa na thamani ya kurudi.

699
00:34:02,040 --> 00:34:05,650
>> Na hivi sasa tumekuwa tu kutumika kazi
kwamba watu wengine wameandika.

700
00:34:05,650 --> 00:34:09,219
Lakini tunaweza kweli kufanya haya
aina ya mambo sisi wenyewe.

701
00:34:09,219 --> 00:34:12,730
Hivyo mimi nina kwenda katika
CS50 appliance tena.

702
00:34:12,730 --> 00:34:16,020
Hebu karibu tab kwamba sisi
alikuwa wazi wakati iliyopita.

703
00:34:16,020 --> 00:34:18,530
Na napenda kwenda mbele na
kuunda faili mpya.

704
00:34:18,530 --> 00:34:22,400
Na mimi nina kwenda mbele na
wito huu positive.c moja.

705
00:34:22,400 --> 00:34:24,770
Hivyo nataka kufanya kitu kwa
chanya namba hapa.

706
00:34:24,770 --> 00:34:27,219
Hivyo mimi nina kwenda mbele na kufanya int -

707
00:34:27,219 --> 00:34:28,000
pole -

708
00:34:28,000 --> 00:34:31,840
# Pamoja.

709
00:34:31,840 --> 00:34:34,280
Hebu si kufanya huo
kosa kama kabla.

710
00:34:34,280 --> 00:34:40,020
Int kuu (utupu), wazi curly
brace, imefungwa curly brace.

711
00:34:40,020 --> 00:34:41,639
>> Na sasa nataka kufanya yafuatayo.

712
00:34:41,639 --> 00:34:44,600
Nataka kuandika mpango kwamba
anasisitiza kwamba mtumiaji anatoa

713
00:34:44,600 --> 00:34:46,770
mimi sifuri.

714
00:34:46,770 --> 00:34:50,969
Hivyo hakuna kazi GetPositiveInt
katika maktaba CS50.

715
00:34:50,969 --> 00:34:52,610
Kuna tu GetInt ().

716
00:34:52,610 --> 00:34:55,790
Lakini hiyo ni sawa kwa sababu nina
constructs na ambayo siwezi kulazimisha

717
00:34:55,790 --> 00:34:59,360
zaidi kidogo kikwazo juu ya thamani hiyo.

718
00:34:59,360 --> 00:35:00,990
Mimi naweza kufanya kitu kama hiki.

719
00:35:00,990 --> 00:35:02,780
>> Hivyo int n -

720
00:35:02,780 --> 00:35:04,920
na kama wewe ni kuandika pamoja, tu kutambua
Mimi nina kwenda nyuma na

721
00:35:04,920 --> 00:35:06,430
kubadilisha baadhi ya mambo katika wakati -

722
00:35:06,430 --> 00:35:09,960
hivyo n int sawa GetInt ().

723
00:35:09,960 --> 00:35:11,780
Na kwamba ni kwenda kuweka
ndani ya int ya n.

724
00:35:11,780 --> 00:35:13,830
Na napenda kuwa na maelezo zaidi.

725
00:35:13,830 --> 00:35:23,270
Basi mimi kusema kitu kama mimi kudai kwamba
wewe nipe sifuri.

726
00:35:23,270 --> 00:35:23,550
>> Wote haki.

727
00:35:23,550 --> 00:35:25,250
Hivyo kidogo tu ya maelekezo.

728
00:35:25,250 --> 00:35:26,270
Na sasa nini naweza kufanya nini?

729
00:35:26,270 --> 00:35:29,840
Naam, mimi tayari kujua kutoka rahisi yangu
hali au matawi, kama mimi

730
00:35:29,840 --> 00:35:36,100
alikuwa katika Scratch, mimi naweza kusema kitu
kama kama n ni kidogo kuliko au sawa na

731
00:35:36,100 --> 00:35:44,460
sifuri, basi nataka kufanya kitu
kama, ambayo si mazuri.

732
00:35:44,460 --> 00:35:45,560
Na kisha mimi naweza kufanya -

733
00:35:45,560 --> 00:35:47,310
OK, lakini mimi kwa kweli wanataka kupata kwamba int.

734
00:35:47,310 --> 00:35:52,020
Ili niweze kwenda juu hapa na mimi naweza aina
wa nakala hii na Indent hii.

735
00:35:52,020 --> 00:35:52,570
Na kisha, OK.

736
00:35:52,570 --> 00:35:56,990
Hivyo kama n ni chini ya au
sawa na sifuri kufanya hili.

737
00:35:56,990 --> 00:35:58,900
>> Sasa, nini kama mtumiaji
haina kushirikiana?

738
00:35:58,900 --> 00:36:01,560
Vizuri, basi mimi naenda
kukopa hii hapa.

739
00:36:01,560 --> 00:36:03,130
Na kisha kwenda katika mimi hapa
na hapa na hapa.

740
00:36:03,130 --> 00:36:06,420
Hivyo hii ni wazi si ya
ufumbuzi, haki?

741
00:36:06,420 --> 00:36:07,810
Kwa sababu hakuna mwisho mbele.

742
00:36:07,810 --> 00:36:13,100
Kama nataka kudai kwamba mtumiaji anatoa
mimi integer chanya, siwezi

743
00:36:13,100 --> 00:36:14,150
kweli kupata int.

744
00:36:14,150 --> 00:36:15,620
Siwezi kisha kuangalia kwa int kwamba.

745
00:36:15,620 --> 00:36:18,570
Lakini basi mimi unataka kuangalia tena na
kuangalia ni tena na kuangalia tena.

746
00:36:18,570 --> 00:36:21,680
Hivyo ni wazi, nini ni bora
kujenga kwa kutumia hapa?

747
00:36:21,680 --> 00:36:22,840
Haki ya wote, hivyo baadhi ya aina ya kitanzi.

748
00:36:22,840 --> 00:36:25,430
>> Hivyo nina kwenda kujikwamua
wa karibu yote ya hii.

749
00:36:25,430 --> 00:36:27,320
Na mimi nataka kupata hii
int angalau mara moja.

750
00:36:27,320 --> 00:36:28,890
Hivyo nina kwenda kusema kufanya -

751
00:36:28,890 --> 00:36:32,110
na mimi itabidi kurudi
wakati katika muda tu -

752
00:36:32,110 --> 00:36:33,050
sasa, kufanya nini?

753
00:36:33,050 --> 00:36:35,860
Mimi naenda kufanya int n anapata GetInt ().

754
00:36:35,860 --> 00:36:36,080
OK.

755
00:36:36,080 --> 00:36:37,250
Hivyo kwamba ni nzuri.

756
00:36:37,250 --> 00:36:39,750
Na sasa jinsi mara nyingi kufanya
Nataka kufanya hili?

757
00:36:39,750 --> 00:36:45,770
>> Napenda kuweka ndani printf ya kitanzi
hivyo siwezi kudai tena na tena,

758
00:36:45,770 --> 00:36:46,740
kama haja kuwa.

759
00:36:46,740 --> 00:36:49,720
Na nini Nataka hii
wakati hali ya kufanya?

760
00:36:49,720 --> 00:36:53,870
Nataka kuendelea kufanya hii
wakati ni nini kesi?

761
00:36:53,870 --> 00:36:54,125
Yeah.

762
00:36:54,125 --> 00:36:55,390
N ni chini ya au sawa na sifuri.

763
00:36:55,390 --> 00:36:58,180
Hivyo tayari, tumekuwa kwa kiasi kikubwa
kusafishwa kanuni hii up.

764
00:36:58,180 --> 00:37:00,700
Tumekuwa alikopa rahisi sana kujenga -
kitanzi do-wakati.

765
00:37:00,700 --> 00:37:04,690
Nimekuwa kuibiwa tu mistari muhimu
ya maadili ya kwamba mimi kuanza kuiga na

766
00:37:04,690 --> 00:37:05,960
pasting, ambayo ilikuwa si busara.

767
00:37:05,960 --> 00:37:09,790
Na hivyo sasa mimi naenda kwa kweli kuweka
katika hapa na tu kufanya hivyo mara moja.

768
00:37:09,790 --> 00:37:12,990
>> Na sasa nini nataka kufanya katika
mwisho wa mpango huu?

769
00:37:12,990 --> 00:37:16,810
Mimi itabidi tu kusema kitu rahisi
kama, shukrani kwa ajili ya - na

770
00:37:16,810 --> 00:37:18,980
Mimi itabidi kufanya% i kwa int -

771
00:37:18,980 --> 00:37:23,270
backslash n, comma, na kisha
kuziba katika n, semicolon.

772
00:37:23,270 --> 00:37:23,910
>> Wote haki.

773
00:37:23,910 --> 00:37:27,290
Basi hebu angalia nini kinatokea sasa
wakati mimi kuendesha mpango huu.

774
00:37:27,290 --> 00:37:30,600
Mimi nina kwenda mbele na
kufanya kufanya chanya.

775
00:37:30,600 --> 00:37:30,880
Damn.

776
00:37:30,880 --> 00:37:31,600
makosa wachache.

777
00:37:31,600 --> 00:37:32,960
Hivyo basi mimi kitabu nyuma hadi kwanza.

778
00:37:32,960 --> 00:37:34,020
Kufanya kazi kwa njia yao nyuma.

779
00:37:34,020 --> 00:37:37,000
Kazi kwa njia yao kutoka juu kwenda chini
wasije kuteleza na tu

780
00:37:37,000 --> 00:37:38,630
jambo moja kuwa na makosa.

781
00:37:38,630 --> 00:37:42,532
Kinachojitokeza tamko la
kazi GetInt ().

782
00:37:42,532 --> 00:37:43,020
Yeah.

783
00:37:43,020 --> 00:37:44,420
Hivyo ilikuwa si ya kutosha.

784
00:37:44,420 --> 00:37:46,760
Mimi aina ya alifanya kosa sawa lakini
tofauti kidogo wakati huu.

785
00:37:46,760 --> 00:37:51,940
Nahitaji si tu ni pamoja na stdio.h lakini
pia cs50.h, ambayo ni pamoja

786
00:37:51,940 --> 00:37:56,770
kinachojulikana maazimio ya kupata int, ambayo
kufundisha appliance, au kufundisha

787
00:37:56,770 --> 00:37:58,760
C nini GetInt () ni.

788
00:37:58,760 --> 00:37:59,550
>> Hivyo basi mimi resave.

789
00:37:59,550 --> 00:38:02,040
Mimi nina kwenda kupuuza makosa mengine
kwa sababu mimi naenda matumaini kwamba wao ni

790
00:38:02,040 --> 00:38:05,210
namna fulani kuhusiana na makosa
Mimi tayari fasta.

791
00:38:05,210 --> 00:38:08,710
Hivyo basi mimi kwenda mbele na recompile
na kufanya chanya, kuingia.

792
00:38:08,710 --> 00:38:09,020
Damn.

793
00:38:09,020 --> 00:38:09,985
Tatu makosa, bado.

794
00:38:09,985 --> 00:38:12,650
Hebu kitabu juu na ya kwanza.

795
00:38:12,650 --> 00:38:14,320
Isiyotumika kutofautiana n.

796
00:38:14,320 --> 00:38:15,850
Tumekuwa si kuonekana hii kabla.

797
00:38:15,850 --> 00:38:17,200
Na hii pia, ni kidogo fumbo.

798
00:38:17,200 --> 00:38:18,850
Hii ni pato la mkusanyaji.

799
00:38:18,850 --> 00:38:23,610
Na nini kuwa mstari yalionyesha
huko - positive.c :9:13 -

800
00:38:23,610 --> 00:38:28,960
ni kusema, ni kusema juu ya mstari wa tisa ya
positive.c, katika tabia ya 13,

801
00:38:28,960 --> 00:38:31,510
Safu ya 13, alifanya kosa hilo.

802
00:38:31,510 --> 00:38:34,230
>> Na hasa, ni kuwaambia
mimi isiyotumika kutofautiana n.

803
00:38:34,230 --> 00:38:35,790
Basi hebu angalia -

804
00:38:35,790 --> 00:38:37,150
line tisa.

805
00:38:37,150 --> 00:38:40,430
Mimi nina kutumia n kwa maana ya kwamba
Mimi kutoa ni thamani.

806
00:38:40,430 --> 00:38:44,200
Lakini nini mkusanyaji hapendi ni
kwamba mimi si inaonekana kutumia.

807
00:38:44,200 --> 00:38:45,560
Lakini kusubiri dakika, mimi ni kwa kutumia hiyo.

808
00:38:45,560 --> 00:38:48,170
Katika mstari wa 11, mimi nina kutumia hapa.

809
00:38:48,170 --> 00:38:52,430
Lakini kama mimi kitabu chini zaidi
saa positive.c :11 -

810
00:38:52,430 --> 00:38:56,230
hivyo katika mstari wa 11, tabia ya 12,
mkusanyaji ni akiniambia, matumizi ya

811
00:38:56,230 --> 00:38:58,670
Undeclared kitambulisho n.

812
00:38:58,670 --> 00:39:02,760
>> Hivyo Undeclared njia nina
si maalum kama

813
00:39:02,760 --> 00:39:04,970
kutofautiana na aina ya data.

814
00:39:04,970 --> 00:39:05,500
Lakini kusubiri dakika.

815
00:39:05,500 --> 00:39:09,150
Mimi hasa kwamba katika mstari tisa.

816
00:39:09,150 --> 00:39:11,100
Hivyo mtu ni kweli kuchanganyikiwa hapa.

817
00:39:11,100 --> 00:39:14,900
Ni ama mimi au mkusanyaji kwa sababu
katika mstari wa tisa, tena, mimi nina kutangaza

818
00:39:14,900 --> 00:39:18,650
int n, na mimi nina kumshirikisha ni
kurudi thamani ya GetInt ().

819
00:39:18,650 --> 00:39:22,930
Basi mimi nina kutumia kwamba n kutofautiana katika mstari
11 na kuangalia kama thamani yake ni chini

820
00:39:22,930 --> 00:39:24,050
zaidi au sawa na sifuri.

821
00:39:24,050 --> 00:39:27,430
Lakini hii inaonekana ni
mbaya na kuvunjwa kwa nini?

822
00:39:27,430 --> 00:39:30,630

823
00:39:30,630 --> 00:39:32,490
Kusema tena?

824
00:39:32,490 --> 00:39:35,690
>> Ah, mimi na kutangaza n kabla ya
kuingia kitanzi.

825
00:39:35,690 --> 00:39:36,370
Lakini kwa nini?

826
00:39:36,370 --> 00:39:39,830
I mean, sisi tu mapendekezo kidogo iliyopita kwamba
ni faini ya kutangaza vigezo

827
00:39:39,830 --> 00:39:43,600
wote kwenye mstari mmoja na kisha
wao hawawajui baadhi ya thamani.

828
00:39:43,600 --> 00:39:46,790
variable kimataifa - hebu kuja nyuma
na kwamba wazo katika muda tu.

829
00:39:46,790 --> 00:39:48,690
Kwa nini unataka mimi kuweka
ni nje ya kitanzi?

830
00:39:48,690 --> 00:40:03,170

831
00:40:03,170 --> 00:40:03,830
Ni.

832
00:40:03,830 --> 00:40:06,780
Hasa.

833
00:40:06,780 --> 00:40:09,610
>> Hivyo, angalau, kwa kiasi fulani counterintuitive,
basi mimi muhtasari.

834
00:40:09,610 --> 00:40:13,510
Wakati wewe kutangaza n ndani
ya kuzuia do pale -

835
00:40:13,510 --> 00:40:16,320
hasa ndani ya
wale braces curly -

836
00:40:16,320 --> 00:40:19,210
kwamba n kutofautiana ana nini
kuitwa wigo -

837
00:40:19,210 --> 00:40:23,210
lisilohusiana na mfumo wa bao yetu katika
shaka - lakini ina wigo kwamba

838
00:40:23,210 --> 00:40:25,190
mdogo kwa braces wale curly.

839
00:40:25,190 --> 00:40:28,460
Kwa maneno mengine, kwa kawaida kama wewe kutangaza
kutofautiana ndani ya seti ya

840
00:40:28,460 --> 00:40:33,370
curly braces, kutofautiana unaendelea tu
ndani ya wale braces curly.

841
00:40:33,370 --> 00:40:37,320
Hivyo kwa kuwa mantiki peke yake, hata kama
Nimekuwa alitangaza n katika mstari tisa, ni

842
00:40:37,320 --> 00:40:41,910
kimsingi kutoweka kutoka upeo,
kutoweka kutoka kumbukumbu, ili kuzungumza,

843
00:40:41,910 --> 00:40:43,370
kwa wakati mimi hit line 11.

844
00:40:43,370 --> 00:40:47,370
Sababu line 11, kwa bahati mbaya, ni
nje ya wale braces curly.

845
00:40:47,370 --> 00:40:51,540
>> Hivyo mimi kwa bahati mbaya hawezi kurekebisha hili kwa
kwenda nyuma kwa nini mimi alifanya hivyo kabla.

846
00:40:51,540 --> 00:40:53,370
Unaweza kwa mara ya kwanza kufanya hivyo.

847
00:40:53,370 --> 00:40:56,370
Lakini ni nini sasa si
kufanya cyclically?

848
00:40:56,370 --> 00:40:58,260
Wewe ni wazi si kupata
int cyclically.

849
00:40:58,260 --> 00:41:01,320
Ili tuweze kuondoka GetInt (), na sisi
tuache GetInt () ndani ya

850
00:41:01,320 --> 00:41:04,420
kitanzi kwa sababu hiyo ni nini tunataka
bemba mtumiaji kwa ajili ya tena na tena.

851
00:41:04,420 --> 00:41:08,660
Lakini haina inatosha kwenda
hadi mstari, kusema, sita.

852
00:41:08,660 --> 00:41:10,150
Int n, semicolon.

853
00:41:10,150 --> 00:41:12,990
Je, si kuwapa thamani lakini, kwa sababu
huna haja tu bado.

854
00:41:12,990 --> 00:41:16,220
>> Lakini sasa hapa chini, ilani - hii
itakuwa kosa rahisi sana.

855
00:41:16,220 --> 00:41:19,440
Sitaki kwa kivuli uliopita yangu
tamko la n.

856
00:41:19,440 --> 00:41:22,830
Nataka kutumia n kwamba
kweli lipo.

857
00:41:22,830 --> 00:41:25,780
Na hivyo sasa katika mstari wa 10,
Mimi hawawajui n thamani.

858
00:41:25,780 --> 00:41:28,580
Lakini katika mstari sita, mimi kutangaza n.

859
00:41:28,580 --> 00:41:32,940
Na hivyo wanaweza au mimi naweza si
kutumia katika mstari wa 12 sasa?

860
00:41:32,940 --> 00:41:37,120
Siwezi kwa sababu kati ya ambayo curly
braces ni n alitangaza sasa?

861
00:41:37,120 --> 00:41:38,770
moja hadi hapa kwenye mstari tano.

862
00:41:38,770 --> 00:41:40,330
Mmoja hapa kwenye mstari 14.

863
00:41:40,330 --> 00:41:49,770
Hivyo kama mimi sasa zoom nje, ila faili hii, kwenda
nyuma katika na kukimbia kufanya chanya,

864
00:41:49,770 --> 00:41:50,820
ulioandaliwa wakati huu.

865
00:41:50,820 --> 00:41:51,940
Hivyo kwamba ni tayari maendeleo.

866
00:41:51,940 --> 00:41:53,640
Kufyeka. . / Chanya, kuingia.

867
00:41:53,640 --> 00:41:56,060
>> Mimi kudai kwamba wewe nipe
sifuri.

868
00:41:56,060 --> 00:41:57,750
Hasi 1.

869
00:41:57,750 --> 00:41:59,020
Hasi 2.

870
00:41:59,020 --> 00:42:00,680
Hasi 3.

871
00:42:00,680 --> 00:42:01,760
Sifuri.

872
00:42:01,760 --> 00:42:03,000
Moja.

873
00:42:03,000 --> 00:42:05,130
Na shukrani kwa ajili ya mtu ni
nini sasa kuchapishwa.

874
00:42:05,130 --> 00:42:07,400
>> Hebu jaribu kitu kingine,
nje ya udadisi.

875
00:42:07,400 --> 00:42:09,600
Mimi kuambiwa pembejeo integer.

876
00:42:09,600 --> 00:42:12,870
Lakini nini kama mimi badala aina katika kondoo?

877
00:42:12,870 --> 00:42:14,460
Hivyo sasa kuona haraka tofauti -

878
00:42:14,460 --> 00:42:15,350
tena.

879
00:42:15,350 --> 00:42:17,670
Lakini hakuna mahali popote katika kanuni yangu
Je, mimi kuandika tena.

880
00:42:17,670 --> 00:42:22,320
Hivyo ambapo, labda, ni hii jaribu tena
haraka kuja kutoka, unaweza kusema?

881
00:42:22,320 --> 00:42:23,540
Yeah, kutoka GetInt () yenyewe.

882
00:42:23,540 --> 00:42:26,650
Hivyo moja ya mambo wafanyakazi CS50 gani
kwa ajili yenu, angalau katika hizi chache kwanza

883
00:42:26,650 --> 00:42:30,400
wiki, ni sisi wameandika baadhi ya kiasi
ya makosa ya kuangalia kuhakikisha kwamba kama

884
00:42:30,400 --> 00:42:34,260
wewe piga GetInt (), wewe angalau
kupata nyuma int kutoka kwa mtumiaji.

885
00:42:34,260 --> 00:42:35,460
Huwezi kupata kamba.

886
00:42:35,460 --> 00:42:36,440
Huwezi kupata Char.

887
00:42:36,440 --> 00:42:39,660
Huwezi kupata kitu
mwingine kabisa.

888
00:42:39,660 --> 00:42:40,510
Utapata int.

889
00:42:40,510 --> 00:42:41,890
>> Sasa, wanaweza kuwa chanya.

890
00:42:41,890 --> 00:42:42,770
Wanaweza kuwa hasi.

891
00:42:42,770 --> 00:42:44,550
Sisi kufanya dhamana hakuna kuzunguka kwamba.

892
00:42:44,550 --> 00:42:48,960
Lakini sisi bemba mtumiaji kujaribu tena,
Jaribu tena, jaribu tena mpaka yeye au yeye kweli

893
00:42:48,960 --> 00:42:49,810
inashirikiana.

894
00:42:49,810 --> 00:42:53,085
Vile vile, kama mimi kufanya 1.23,
kwamba si int.

895
00:42:53,085 --> 00:42:58,400
Lakini kama mimi aina katika, kusema, 50, kwamba
anitiaye thamani ya kwamba nilitaka.

896
00:42:58,400 --> 00:42:59,050
>> Wote haki.

897
00:42:59,050 --> 00:43:01,380
Hivyo si mbaya.

898
00:43:01,380 --> 00:43:04,780
Maswali yoyote juu ya nini tumekuwa tu kufanyika?

899
00:43:04,780 --> 00:43:07,930
takeaway muhimu, kwa kuwa wazi, si
sana kitanzi, ambayo tumeona

900
00:43:07,930 --> 00:43:10,880
kabla hata kama sisi si kweli
kutumika, lakini suala la wigo, ambapo

901
00:43:10,880 --> 00:43:17,045
vigezo inaweza tu inaweza tu kutumika
ndani ya baadhi ya wigo maalum.

902
00:43:17,045 --> 00:43:19,830
>> Haki ya yote, napenda kushughulikia maoni
uliyofanya awali, kwamba wa

903
00:43:19,830 --> 00:43:20,860
kimataifa kutofautiana.

904
00:43:20,860 --> 00:43:24,880
Kama kando, zinageuka kuwa mwingine
ufumbuzi wa tatizo hili, lakini

905
00:43:24,880 --> 00:43:28,880
kawaida ufumbuzi sahihi au
ufumbuzi hafifu iliyoundwa, ni

906
00:43:28,880 --> 00:43:31,670
kutangaza kutofautiana yako kama nini
kuitwa variable kimataifa.

907
00:43:31,670 --> 00:43:34,610
Sasa mimi nina aina ya kukiuka tafsiri yangu
ya wigo kwa sababu kuna

908
00:43:34,610 --> 00:43:37,680
hakuna braces curly saa ya juu sana
na chini sana ya faili.

909
00:43:37,680 --> 00:43:40,190
Lakini maana ya kwamba
ni kwamba sasa katika mstari nne,

910
00:43:40,190 --> 00:43:41,710
n ni variable kimataifa.

911
00:43:41,710 --> 00:43:44,460
Na kama jina ina maana, ni
tu kupatikana kila mahali.

912
00:43:44,460 --> 00:43:45,790
>> Mwanzo kwa kweli ina hizi.

913
00:43:45,790 --> 00:43:48,650
Kama kutumika kutofautiana, unaweza kukumbuka
wewe alikuwa na kuchagua kama ni kwa ajili ya

914
00:43:48,650 --> 00:43:50,780
hii sprite au kwa ajili ya wote sprites.

915
00:43:50,780 --> 00:43:54,270
Naam, kila sprites ni wazi
njia ya kusema kimataifa.

916
00:43:54,270 --> 00:43:55,520
Yeah?

917
00:43:55,520 --> 00:44:09,690

918
00:44:09,690 --> 00:44:10,990
Ah, mzuri swali.

919
00:44:10,990 --> 00:44:14,310
>> Hivyo kukumbuka kwamba katika toleo sana kwanza
ya maadili wangu, wakati mimi kimakosa

920
00:44:14,310 --> 00:44:17,700
alitangaza na inavyoelezwa n katika mstari tisa -

921
00:44:17,700 --> 00:44:19,980
Mimi amekiri ni kama variable
na mimi akampa thamani na

922
00:44:19,980 --> 00:44:21,160
operator zoezi -

923
00:44:21,160 --> 00:44:22,520
hii alinipa makosa mawili.

924
00:44:22,520 --> 00:44:26,560
Moja, ukweli kwamba n ilikuwa si kutumika,
na wawili, kuwa katika mstari wa 11

925
00:44:26,560 --> 00:44:27,770
ni tu si alitangaza.

926
00:44:27,770 --> 00:44:31,120
Hivyo moja ya kwanza mimi si
anuani ya wakati huo.

927
00:44:31,120 --> 00:44:35,130
Ni kosa si madhubuti ya kutangaza
kutofautiana lakini si matumizi yake.

928
00:44:35,130 --> 00:44:38,540
Lakini moja ya mambo tumefanya katika
Appliance CS50, kwa makusudi,

929
00:44:38,540 --> 00:44:43,340
pedagogically, ni tumekuwa cranked up
matarajio ya mkusanyaji kufanya

930
00:44:43,340 --> 00:44:46,970
uhakika kwamba wewe ni kufanya mambo si tu
usahihi lakini kwa kweli kwa usahihi.

931
00:44:46,970 --> 00:44:51,520
>> Kwa sababu kama wewe ni kutangaza variable
kama n na kamwe kutumia, au kutumia

932
00:44:51,520 --> 00:44:53,700
usahihi, basi kile
ni kufanya ni huko?

933
00:44:53,700 --> 00:44:55,650
Ni kweli mtumishi hakuna kusudi.

934
00:44:55,650 --> 00:44:58,980
Na ni rahisi sana baada ya muda, kama wewe
wala configure kompyuta yako mwenyewe katika

935
00:44:58,980 --> 00:45:01,960
njia hii, ili tu kuwa na kanuni ambayo ina
kidogo mabaki hapa, mabaki huko.

936
00:45:01,960 --> 00:45:04,390
Na kisha baada ya miezi wewe kuangalia nyuma na
wewe ni kama, kwa nini ni line hii ya

937
00:45:04,390 --> 00:45:05,060
kanuni ya huko?

938
00:45:05,060 --> 00:45:07,940
Na kama hakuna sababu nzuri, ni
haina faida wewe au wenzako

939
00:45:07,940 --> 00:45:10,650
chini ya barabara kuwa na
mashaka juu ya basi.

940
00:45:10,650 --> 00:45:12,540
>> Kama kando, ambapo ni
kwamba kuja kutoka?

941
00:45:12,540 --> 00:45:16,410
Naam, kukumbuka kwamba kila wakati sisi kukusanya
mpango, kila ya mambo haya ni

942
00:45:16,410 --> 00:45:17,380
yanachapishwa.

943
00:45:17,380 --> 00:45:18,350
Hivyo tutaweza kuja nyuma hii.

944
00:45:18,350 --> 00:45:22,230
Lakini tena, kufanya ni shirika kwamba
automates mchakato wa kuandaa na

945
00:45:22,230 --> 00:45:24,830
mbio mkusanyaji halisi
kuitwa Clang.

946
00:45:24,830 --> 00:45:27,650
Jambo hili, tutaweza hatimaye kuona, ana
kufanya na debugging na maalum

947
00:45:27,650 --> 00:45:29,060
programu inayoitwa debugger.

948
00:45:29,060 --> 00:45:32,150
Hii ina nini na optimizing
kanuni - zaidi juu ya kwamba katika siku zijazo.

949
00:45:32,150 --> 00:45:33,620
Std = C99 -

950
00:45:33,620 --> 00:45:37,870
hii ina maana kutumia toleo la 1999 ya
C C. imekuwa karibu hata zaidi ya

951
00:45:37,870 --> 00:45:40,830
kwamba, lakini alifanya baadhi nice
mabadiliko 10 pamoja na miaka iliyopita.

952
00:45:40,830 --> 00:45:42,690
>> Na hapa ndio husika.

953
00:45:42,690 --> 00:45:45,880
Tunasema kufanya chochote ambacho
awali ingekuwa onyo

954
00:45:45,880 --> 00:45:48,560
kosa kuzuia mwanafunzi
kutoka kuandaa.

955
00:45:48,560 --> 00:45:51,400
Na ukuta njia kufanya hivyo kwa
nzima rundo la vitu, si

956
00:45:51,400 --> 00:45:53,060
tu kuhusiana na vigezo.

957
00:45:53,060 --> 00:45:54,700
Na kisha basi mimi kitabu kwa
mwisho wa mstari huu.

958
00:45:54,700 --> 00:45:56,430
Na hii, pia, tutaweza hatimaye
kuja nyuma.

959
00:45:56,430 --> 00:45:59,040
Hii ni wazi jina la
faili Mimi naandika.

960
00:45:59,040 --> 00:46:02,160
Hii anakumbuka jina la faili
Mimi outputting kama jina

961
00:46:02,160 --> 00:46:04,070
ya mpango wangu runnable.

962
00:46:04,070 --> 00:46:08,970
Hii lcs50-tu ina maana kutumia CS50
maktaba, na zeros yoyote na wale ambao

963
00:46:08,970 --> 00:46:12,390
wafanyakazi aliandika na ulioandaliwa mapema
mwaka huu, kuunganisha

964
00:46:12,390 --> 00:46:13,490
yao katika mpango wangu.

965
00:46:13,490 --> 00:46:16,130
>> Na mtu yeyote kujua nini-LM ni?

966
00:46:16,130 --> 00:46:18,150
Ni maktaba math, ambayo ni
pale tu hata kama wewe ni

967
00:46:18,150 --> 00:46:19,320
si kufanya lolote math.

968
00:46:19,320 --> 00:46:22,620
Ni tu moja kwa moja zinazotolewa
kwetu na kufanya.

969
00:46:22,620 --> 00:46:26,540
>> Vizuri, basi mimi kufanya moja nyingine mfano
hapa kwa kufungua faili mpya.

970
00:46:26,540 --> 00:46:30,560
Na napenda kuokoa hii moja kama string.c.

971
00:46:30,560 --> 00:46:37,980
Ni zinageuka kuwa kama sisi majadiliano juu ya data
aina ya leo, kuna hata zaidi

972
00:46:37,980 --> 00:46:40,630
kinachoendelea chini ya Hood
kuliko tumeona hivi sasa.

973
00:46:40,630 --> 00:46:42,290
Hivyo basi mimi haraka kufanya mpango wa haraka.

974
00:46:42,290 --> 00:46:44,510
Pamoja stdio.h.

975
00:46:44,510 --> 00:46:45,730
Na mimi itabidi kuokoa.

976
00:46:45,730 --> 00:46:48,110
Na unajua, basi mimi si kufanya
huo makosa tena na tena.

977
00:46:48,110 --> 00:46:50,540
Pamoja cs50.h.

978
00:46:50,540 --> 00:46:54,870
Na napenda kwenda mbele sasa
na kufanya kuu int (batili).

979
00:46:54,870 --> 00:46:58,790
>> Na sasa mimi tu wanataka kufanya mpango
kwamba anafanya hii - kutangaza kamba

980
00:46:58,790 --> 00:47:03,610
kuitwa s na kupata kamba
kutoka kwa mtumiaji.

981
00:47:03,610 --> 00:47:05,820
Na napenda kufanya kidogo
maelekezo hapa -

982
00:47:05,820 --> 00:47:09,960
tafadhali nipe kamba - hivyo
mtumiaji anajua nini cha kufanya.

983
00:47:09,960 --> 00:47:13,190
Na kisha chini hapa chini hii,
Nataka kufanya yafuatayo -

984
00:47:13,190 --> 00:47:16,060
kwa int i anapata sifuri.

985
00:47:16,060 --> 00:47:18,580
Tena, kompyuta wanasayansi kawaida
kuanza kuhesabu saa sifuri, lakini tunaweza

986
00:47:18,580 --> 00:47:20,340
kufanya kuwa moja kama kweli sisi alitaka.

987
00:47:20,340 --> 00:47:27,240
Sasa mimi nina kwenda kufanya i ni chini
kuliko urefu wa kamba ya s.

988
00:47:27,240 --> 00:47:28,430
Hivyo strlen -

989
00:47:28,430 --> 00:47:29,510
S-T-A-L-E-N -

990
00:47:29,510 --> 00:47:31,650
tena, ni mafupi kwa sababu ni rahisi
na aina, hata kama ni

991
00:47:31,650 --> 00:47:32,590
kidogo fumbo.

992
00:47:32,590 --> 00:47:35,290
>> Hii ni kazi tumekuwa si kutumika
kabla lakini literally gani kwamba -

993
00:47:35,290 --> 00:47:37,810
kurudi kwangu idadi hiyo inawakilisha
urefu wa kamba

994
00:47:37,810 --> 00:47:38,690
kwamba mtumiaji typed.

995
00:47:38,690 --> 00:47:41,740
Kama wao typed katika hello, ingekuwa kurudi
tano kwa sababu kuna tano

996
00:47:41,740 --> 00:47:42,890
barua katika hello.

997
00:47:42,890 --> 00:47:45,390
Basi, juu ya kila iteration ya
hii kitanzi, i pamoja plus.

998
00:47:45,390 --> 00:47:49,170
Hivyo tena, kiwango kujenga hata kama
wewe si kabisa pia starehe au

999
00:47:49,170 --> 00:47:50,420
ukoo na ni bado.

1000
00:47:50,420 --> 00:47:53,220
>> Lakini sasa juu ya kila iteration ya kitanzi hii,
taarifa ya nini mimi nina kwenda kufanya.

1001
00:47:53,220 --> 00:47:56,690
Nataka kwenda mbele na magazeti
nje tabia moja -

1002
00:47:56,690 --> 00:47:59,940
hivyo% c backslash n juu ya mstari mpya.

1003
00:47:59,940 --> 00:48:00,990
Na kisha, unajua nini nataka kufanya?

1004
00:48:00,990 --> 00:48:05,090
Chochote neno ni kwamba mtumiaji aina
katika, kama hello, nataka magazeti

1005
00:48:05,090 --> 00:48:09,530
H-E-L-L-O, tabia moja kwa kila mstari.

1006
00:48:09,530 --> 00:48:13,080
Kwa maneno mengine, nataka kupata saa
mtu binafsi wahusika katika kamba,

1007
00:48:13,080 --> 00:48:16,770
ambapo hadi sasa ina kamba tu
imekuwa mlolongo wa wahusika.

1008
00:48:16,770 --> 00:48:21,690
>> Na zinageuka siwezi kufanya s, bracket,
i, karibu bracket, karibu

1009
00:48:21,690 --> 00:48:23,580
mabano, semicolon.

1010
00:48:23,580 --> 00:48:25,640
Na mimi kufanya jambo moja zaidi.

1011
00:48:25,640 --> 00:48:30,570
Ni katika faili iitwayo string.h
strlen kwamba ni kutangazwa.

1012
00:48:30,570 --> 00:48:33,190
Hivyo kama nataka kutumia kwamba kazi,
Mimi haja ya kuwaambia mkusanyaji,

1013
00:48:33,190 --> 00:48:34,450
wanatarajia kuitumia.

1014
00:48:34,450 --> 00:48:37,040
Sasa napenda kwenda mbele na kufanya
programu inayoitwa kamba.

1015
00:48:37,040 --> 00:48:39,150
Dot, kufyeka, kamba.

1016
00:48:39,150 --> 00:48:40,130
>> Tafadhali nipe kamba.

1017
00:48:40,130 --> 00:48:40,900
Mimi itabidi kwenda mbele na aina yake.

1018
00:48:40,900 --> 00:48:43,040
Hello, katika mechi zote, kuingia.

1019
00:48:43,040 --> 00:48:47,390
Na sasa nimepata taarifa zilizochapishwa hii
tabia moja baada ya nyingine.

1020
00:48:47,390 --> 00:48:51,450
Hivyo undani mpya hapa ni kwamba kamba,
mwisho wa siku, unaweza kuwa

1021
00:48:51,450 --> 00:48:54,810
kupatikana kwa njia ya mtu binafsi yake
wahusika kwa kuanzisha mraba

1022
00:48:54,810 --> 00:48:55,840
bracket nukuu.

1023
00:48:55,840 --> 00:48:59,090
Na kwamba kwa sababu kamba chini ya
Hood ni kweli mlolongo wa

1024
00:48:59,090 --> 00:48:59,810
wahusika.

1025
00:48:59,810 --> 00:49:02,010
Lakini nini kuhusu wao ni nadhifu
katika RAM ya kompyuta yako -

1026
00:49:02,010 --> 00:49:05,300
Mac, PC, chochote ni - wao ni
halisi nyuma kwa nyuma kwa nyuma -

1027
00:49:05,300 --> 00:49:06,225
H-E-L-L-O -

1028
00:49:06,225 --> 00:49:09,920
saa binafsi, karibu
ka katika kumbukumbu.

1029
00:49:09,920 --> 00:49:13,210
>> Hivyo kama unataka kupata saa vile nane
Byte, ambayo katika kitanzi hii itakuwa

1030
00:49:13,210 --> 00:49:16,900
bracket sifuri, bracket moja, bracket mbili,
bracket tatu, bracket nne -

1031
00:49:16,900 --> 00:49:18,890
hiyo ni sifuri indexed hadi tano -

1032
00:49:18,890 --> 00:49:23,330
kwamba magazeti nje ya H-E-L-L-O
kwenye mstari wake mwenyewe.

1033
00:49:23,330 --> 00:49:26,320
>> Sasa, kama kichocheo, napenda kuonyesha
aina ya mambo itabidi hatimaye kuwa

1034
00:49:26,320 --> 00:49:31,950
uwezo wa kuelewa, angalau
kwa karibu baadhi ya kuangalia.

1035
00:49:31,950 --> 00:49:35,610
Kwa moja, nini sisi ni pamoja na katika leo
mifano, kama Ningependa, ni kweli

1036
00:49:35,610 --> 00:49:38,300
moja ya jailbreaks sana kwanza
kwa iPhone.

1037
00:49:38,300 --> 00:49:40,800
Jailbreaking ina maana ngozi simu
hivyo unaweza kweli kutumia kwenye

1038
00:49:40,800 --> 00:49:43,380
mbalimbali carrier au kufunga
programu yako mwenyewe.

1039
00:49:43,380 --> 00:49:45,660
Na wewe utakuwa taarifa hii inaonekana kabisa
fumbo, uwezekano mkubwa.

1040
00:49:45,660 --> 00:49:46,520
Lakini tuangalie hii.

1041
00:49:46,520 --> 00:49:50,420
iPhone ilikuwa inaonekana kupasuka na
kwa kitanzi, hali kama, mwingine

1042
00:49:50,420 --> 00:49:52,580
hali, rundo la kazi
tumekuwa si kuonekana.

1043
00:49:52,580 --> 00:49:54,230
>> Na tena, utakuwa si wakati
mtazamo wa kwanza pengine

1044
00:49:54,230 --> 00:49:55,620
kuelewa jinsi hii ni kazi.

1045
00:49:55,620 --> 00:49:58,940
Lakini kila kitu kwamba sisi aina ya kuchukua
kwa nafasi katika maisha yetu ya kisasa

1046
00:49:58,940 --> 00:50:02,040
kweli huelekea kupunguza hata kwa baadhi
ya misingi hizi tumekuwa

1047
00:50:02,040 --> 00:50:02,820
kuangalia.

1048
00:50:02,820 --> 00:50:06,680
Hebu kwenda mbele na kufungua moja
nyingine ya mpango, holloway.c.

1049
00:50:06,680 --> 00:50:08,970
Hivyo hii, pia, ni jambo
lazima si kweli kujua.

1050
00:50:08,970 --> 00:50:12,440
Hata hakuna hata mmoja wa wafanyakazi au ningeweza
pengine takwimu hii nje kwa kuangalia

1051
00:50:12,440 --> 00:50:15,450
ni kwa sababu hii ilikuwa kanuni ya mtu
kwamba iliwasilishwa kwa nini

1052
00:50:15,450 --> 00:50:19,630
kihistoria inayojulikana kama C obfuscated
mashindano, ambapo wewe kuandika mpango

1053
00:50:19,630 --> 00:50:24,670
kwamba inaandaa na anaendesha lakini ni hivyo damn
cryptic hakuna binadamu wanaweza kuelewa kile

1054
00:50:24,670 --> 00:50:27,530
ni kwenda kufanya mpaka
wao kweli kukimbia.

1055
00:50:27,530 --> 00:50:29,940
>> Hivyo kweli, kama ukiangalia katika hii
kanuni, naona kubadili.

1056
00:50:29,940 --> 00:50:30,870
Mimi naona kuu.

1057
00:50:30,870 --> 00:50:33,800
Mimi naona haya mabano mraba ikimaanisha
baadhi ya aina ya safu.

1058
00:50:33,800 --> 00:50:35,970
Je, mtu yeyote unataka nadhani nini
mpango huu kwa kweli

1059
00:50:35,970 --> 00:50:37,220
gani kama mimi kukimbia Holloway?

1060
00:50:37,220 --> 00:50:39,940

1061
00:50:39,940 --> 00:50:40,750
Ndiyo.

1062
00:50:40,750 --> 00:50:43,050
OK.

1063
00:50:43,050 --> 00:50:44,690
Vizuri.

1064
00:50:44,690 --> 00:50:48,090
Hivyo tu wafanyakazi na siwezi kufikiri
nje ya mambo haya kufanya.

1065
00:50:48,090 --> 00:50:51,670
>> Na sasa Mwisho, napenda kwenda mbele
na kufungua nyingine moja mpango.

1066
00:50:51,670 --> 00:50:53,440
Hii moja -

1067
00:50:53,440 --> 00:50:55,550
tena, tutaweza kufanya kanuni chanzo
inapatikana online - hii moja tu

1068
00:50:55,550 --> 00:50:57,480
aina ya pretty kuangalia.

1069
00:50:57,480 --> 00:50:59,750
Wote walifanya ni hit
nafasi bar kidogo kabisa.

1070
00:50:59,750 --> 00:51:01,320
Lakini hii ni halisi ya kanuni.

1071
00:51:01,320 --> 00:51:04,790
Hivyo kama unadhani kwamba pretty, kama sisi
kweli kuendesha hii ifikapo haraka,

1072
00:51:04,790 --> 00:51:08,970
hatimaye utaona jinsi sisi
ili kufanya mambo kama haya.

1073
00:51:08,970 --> 00:51:14,008
>> Hivyo tutaweza kuondoka wewe kumbuka kwamba
na kuona juu ya Jumatano.

1074
00:51:14,008 --> 00:51:18,440
>> [Halisi kucheza]

1075
00:51:18,440 --> 00:51:23,380
>> SPIKA 2: Katika CS50 ijayo,
TFS hatua ya uasi.

1076
00:51:23,380 --> 00:51:24,112
>> SPIKA 3: Kuna yeye ni.

1077
00:51:24,112 --> 00:51:25,362
Kupata naye!

1078
00:51:25,362 --> 00:51:29,912

1079
00:51:29,912 --> 00:51:32,074
>> [Halisi kucheza]