1
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>> [MUSIC KUCHEZA]

2
00:00:01,110 --> 00:00:10,567

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00:00:10,567 --> 00:00:11,650
DAVID J. Malan: All wa kulia.

4
00:00:11,650 --> 00:00:15,610
Hii ni CS50, na hii
ni mwisho wa Wiki ya Nne.

5
00:00:15,610 --> 00:00:19,420
Na moja ya mada leo
ni ile ya forensics digital,

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00:00:19,420 --> 00:00:20,989
sanaa ya kurejesha habari.

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Na hakika, hata kama
wewe ni katikati

8
00:00:22,780 --> 00:00:25,070
hivi sasa ya Amani katika Tatu
na kuzuka, wiki ijayo,

9
00:00:25,070 --> 00:00:27,880
mkazo uwe kwenye
just uwanja huu.

10
00:00:27,880 --> 00:00:30,686
>> Hivyo moja ya kazi coolest mimi milele
alikuwa alikuwa nyuma katika shule ya kuhitimu,

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wakati nilikuwa kazi kwa ajili ya mitaa
Middlesex County Wilaya ya Mwanasheria

12
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ofisi, kufanya forensics kazi.

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Hivyo kimsingi, Massachusetts
Hali Polisi, juu ya tukio,

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00:00:37,450 --> 00:00:40,100
wakati wa kufanya kazi juu ya kesi ingekuwa
kuleta katika mambo kama anatoa ngumu

15
00:00:40,100 --> 00:00:42,185
na floppy disks na
kadi ya kumbukumbu na kama.

16
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Na wangeweza mkono wao
kwangu na mshauri wangu,

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na lengo letu lilikuwa kupata ushahidi,
kama kulikuwa na yoyote, kwenye vyombo vya habari hizi.

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Kiza sasa, unaweza kuwa na kuonekana
wa ulimwengu huu wa forensics

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katika vyombo vya habari, TV na sinema.

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Lakini kazi Mimi nilikuwa, na
daresay dunia kwamba,

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ni si kabisa kama ungependa kuona.

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Hebu kuangalia nini
ve pengine kuona.

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[VIDEO avspelning]

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-OK.

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Sasa, hebu kupata nzuri kuangalia wewe.

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>> [MUSIC KUCHEZA]

27
00:01:06,850 --> 00:01:12,260

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>> -Hold Yake.

29
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Kukimbia kwamba nyuma.

30
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>> -Wait Dakika.

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Kwenda kulia.

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-Kuna.

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Freeze hiyo.

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-Kamili-Screen.

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>> -OK.

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Freeze hiyo.

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-Tighten Juu ya kwamba, je,?

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>> -Vector Katika juu ya kwamba
guy na gurudumu nyuma.

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>> -Zoom Katika haki hapa kwenye doa hii.

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>> -Kwa Vifaa sahihi,
picha inaweza wazi na makali.

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>> -Nini Hiyo?

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>> -Ni Ni mpango kukuza.

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>> -Je Wewe wazi kwamba up yoyote?

45
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>> -I Hawajui.

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Hebu kuongeza yake.

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>> -Enhance Sehemu A6.

48
00:01:35,440 --> 00:01:36,570

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Mimi kuimarishwa undani, and--

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-I Nadhani kuna kutosha kuimarisha.

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Kutolewa kwa screen yangu.

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>> -I Kuimarishwa reflection katika macho yake.

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-Let Kukimbia hii kwa njia ya
video kukuza.

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>> -Edgar, Unaweza kuongeza hii?

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>> -Hang Juu ya.

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00:01:45,710 --> 00:01:47,570

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>> -I've Wamekuwa wakifanya kazi katika reflection huu.

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>> Reflection -Kuna ya mtu.

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>> -Reflection.

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-Kuna Ni reflection ya uso wa mtu.

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>> -The Reflection!

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-Kuna Ni reflection.

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-Zoom Katika juu ya kioo.

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Unaweza kuona reflection.

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>> -Je Wewe kuongeza picha kutoka hapa?

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00:01:59,630 --> 00:02:00,377

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-Je Wewe kuongeza yake?

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-Je Wewe kuongeza yake?

69
00:02:02,190 --> 00:02:03,066
-Je Sisi kuongeza hii?

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00:02:03,066 --> 00:02:03,898
-Je Wewe kuongeza yake?

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-Hold Ya pili.

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Mimi itabidi kuongeza.

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-Zoom Katika juu ya mlango.

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-Times 10.

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-Zoom.

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-Move Katika.

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-Zaidi.

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-Wait, Kuacha.

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-Stop.

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-Pause Yake.

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-Rotate Us digrii 75
karibu wima, tafadhali.

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>> -Stop.

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Nenda nyuma sehemu
juu ya mlango tena.

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>> -Got Picha enhancer ambayo inaweza bitmap?

86
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>> -Maybe Tunaweza kutumia Pradeep Singh
njia ya kuona ndani ya madirisha.

87
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>> Programu -The ni hali ya sanaa.

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>> -The Eigenvalue ni mbali.

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>> -Kwa Haki
mchanganyiko wa algorithms--

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>> Hapo ya kuchukuliwa kuja
algorithms ngazi ya pili,

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na siwezi matumizi yao ya
kuongeza picha hii.

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>> -Lock Juu na kupanua z-mhimili.

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>> -Enhance.

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Kuimarisha.

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-Enhance.

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-Freeze Na kuongeza.

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[END video avspelning]

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DAVID J. Malan: Hivyo wale ni
maneno hayo yote, lakini hawakuwa

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kutumika katika hukumu kwa usahihi.

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Na hakika katika siku zijazo, wakati wowote,
tafadhali, wewe kusikia mtu kusema neno,

101
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"Kuongeza," chuckle kidogo tu.

102
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Kwa sababu wakati wewe kujaribu kuboresha,
kwa mfano, hii ni kile kinachotokea.

103
00:02:57,190 --> 00:02:58,580
>> Hivyo hapa ni picha gorgeous.

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00:02:58,580 --> 00:02:59,720
Hii ni CS50 ya mwenyewe Daven.

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Na kudhani kwamba sisi alitaka
kuzingatia katika juu ya twinkle katika jicho lake,

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au reflection ya
guy mbaya kwamba ilikuwa wazi

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00:03:05,870 --> 00:03:07,820
alitekwa na kamera ya usalama.

108
00:03:07,820 --> 00:03:10,330
Hii ni kile kinachotokea wakati
wewe zoom katika juu ya picha kwamba

109
00:03:10,330 --> 00:03:14,060
ina tu idadi finite
ya bits yanayohusiana na hayo.

110
00:03:14,060 --> 00:03:15,420
>> Hiyo ni nini ungependa kupata.

111
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Na hakika, katika jicho Daven ya
ni lakini nne, labda sita saizi

112
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ambayo kutunga nini hasa
mara glimmering huko.

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00:03:22,110 --> 00:03:25,890
Hivyo Set Tatizo Tarakimu hatimaye kuwa na
wewe kuchunguza dunia hii, hasa

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na asili ya kitu
sisi kuwaita faili i / o, ambapo

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i / o ni njia tu ya dhana ya
akisema pembejeo na mazao.

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00:03:31,000 --> 00:03:34,280
>> Hivyo hivi sasa, yote ya mwingiliano
tulikuwa na kompyuta

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wamekuwa kwa kiasi kikubwa na yako
keyboard na screen,

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lakini si sana na disk ngumu,
au kuokoa files ya zaidi ya wale wewe

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mwenyewe kuandika.

120
00:03:41,620 --> 00:03:44,570
Mipango yako hivi sasa na
si kujenga, na kuokoa,

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na uppdatering files yao wenyewe.

122
00:03:46,270 --> 00:03:47,150
>> Naam, ni nini faili ni nani?

123
00:03:47,150 --> 00:03:48,105
Naam, kitu kama JPEG.

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00:03:48,105 --> 00:03:50,520
Hii ni picha waweza
na au upload kwa Facebook,

125
00:03:50,520 --> 00:03:51,690
au kuona mahali popote kwenye mtandao.

126
00:03:51,690 --> 00:03:54,460
Hakika, kwamba picha sisi tu
saw ya Daven mara JPEG.

127
00:03:54,460 --> 00:03:57,570
Na nini kuvutia
kuhusu files kama JPEGs

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00:03:57,570 --> 00:04:02,170
ni kwamba wanaweza kuwa na kutambuliwa,
kawaida, na mifumo ya baadhi ya bits.

129
00:04:02,170 --> 00:04:05,200
>> Kwa maneno mengine, je ni kwamba
tofauti kati ya JPEG kutoka GIF

130
00:04:05,200 --> 00:04:08,109
kutoka PING kutoka kwa Neno la
hati kutoka Excel file?

131
00:04:08,109 --> 00:04:09,900
Naam, ni tofauti tu
mifumo ya bits.

132
00:04:09,900 --> 00:04:12,820
Na wale mifumo tofauti ni
kawaida katika mwanzo wa files wale.

133
00:04:12,820 --> 00:04:18,200
>> Hivyo kwamba wakati kompyuta yako kuufungua Neno
doc, au wakati kompyuta kufungua JPEG,

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inaonekana kawaida katika
kwanza bits kadhaa katika faili.

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00:04:20,940 --> 00:04:24,059
Na kama ni inatambua muundo,
inasema, oh, hii ni picha.

136
00:04:24,059 --> 00:04:25,850
Hebu kuonyesha ni kwa
user kama graphic.

137
00:04:25,850 --> 00:04:27,870
Au, oh, hii inaonekana kama Neno doc.

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00:04:27,870 --> 00:04:30,480
Hebu kuonyesha kuwa na user kama insha.

139
00:04:30,480 --> 00:04:33,020
>> Hivyo kwa mfano, JPEGs,
ni zamu nje, ni

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00:04:33,020 --> 00:04:35,460
haki kisasa
chini ya Hood.

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00:04:35,460 --> 00:04:40,140
Lakini kwanza ka tatu katika wengi kila
JPEG kuanza na namba hizi tatu.

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Hivyo Byte sifuri, moja, na wawili ni, katika
wengi kila JPEG, 255, kisha ya simu

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216, kisha namba 255.

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00:04:46,675 --> 00:04:48,990
>> Na nini wewe utakuwa na uwezo
kuanza kufanya wiki ijayo

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ni kweli poking chini ya
kofia ya files kama JPEGs

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na kama files bitmap, na kuona
nini daima imekuwa pale kwa muda mrefu

147
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kama wewe tumekuwa kutumia kompyuta.

148
00:04:58,650 --> 00:05:01,860
>> Lakini kuna nini huko ni si kawaida
imeandikwa kama namba decimal kama hii.

149
00:05:01,860 --> 00:05:04,620
Wanasayansi wa kompyuta kufanya si
huwa na kusema katika decimal.

150
00:05:04,620 --> 00:05:06,139
Wao si kweli kuzungumza katika binary.

151
00:05:06,139 --> 00:05:07,930
Kwa kawaida, wakati tunataka
kueleza idadi,

152
00:05:07,930 --> 00:05:10,710
sisi kweli matumizi hexadecimal,
ambayo unaweza kukumbuka

153
00:05:10,710 --> 00:05:13,027
kutoka, kusema, Tatizo Set
Moja, ambayo changamoto ya

154
00:05:13,027 --> 00:05:14,610
wewe kufikiri juu ya mfumo tofauti.

155
00:05:14,610 --> 00:05:17,170
>> Sisi, bila shaka, ni ukoo
na decimal, zero kwa njia ya tisa.

156
00:05:17,170 --> 00:05:18,215
Sisi aliyesema kuhusu binary.

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Na sisi si kweli kuwa
kutumia kiasi kwamba hapa

158
00:05:20,710 --> 00:05:22,470
juu ya nje, kwa sababu kompyuta kutumia hiyo.

159
00:05:22,470 --> 00:05:24,900
Lakini programmers mapenzi sana
mara nyingi, lakini si mara zote,

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kutumia hexadecimal, ambayo ina maana tu
una barua 16 katika alfabeti yako,

161
00:05:29,360 --> 00:05:31,330
kinyume na mbili au 10.

162
00:05:31,330 --> 00:05:34,530
>> Hivyo ni jinsi gani wewe kuhesabu juu
ya tisa katika hexadecimal?

163
00:05:34,530 --> 00:05:41,120
Unaweza kwenda 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
a, b, c, d, e, f, tu kwa mkataba.

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00:05:41,120 --> 00:05:43,540
Lakini nini muhimu ni kwamba kila
kati ya hayo ni ishara moja.

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Hakuna 10.

166
00:05:44,340 --> 00:05:48,400
Hakuna 11, per se, kwa sababu kila
ya tarakimu yako, tu kama katika decimal

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00:05:48,400 --> 00:05:51,940
na kama tu katika binary, lazima tu
kuwa tabia moja, na mkataba.

168
00:05:51,940 --> 00:05:55,280
>> Hivyo kwamba basi ni alfabeti tuna
tulizonazo kwa hexadecimal.

169
00:05:55,280 --> 00:05:58,600
Kwa hiyo ni nini JPEG kuangalia kama kama wewe
walikuwa na kuandika wale watatu wa kwanza

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00:05:58,600 --> 00:06:01,980
ka si kama decimal lakini,
kwa mfano, kama hexadecimal?

171
00:06:01,980 --> 00:06:03,640
Na kwa nini ni hex hata yote muhimu?

172
00:06:03,640 --> 00:06:05,290
>> Naam, kuangalia haraka katika mfano.

173
00:06:05,290 --> 00:06:09,030
Hivyo kama mimi kuandika bits kwamba
kuwakilisha hizi numbers-- decimal

174
00:06:09,030 --> 00:06:12,450
hii inaweza kuwa kutu kidogo
sasa kutoka wiki chache nyuma,

175
00:06:12,450 --> 00:06:14,820
lakini moja wa kushoto na
haki moja ni pretty rahisi.

176
00:06:14,820 --> 00:06:17,990
255 ilikuwa kubwa idadi sisi
inaweza kuwakilisha na bits nane.

177
00:06:17,990 --> 00:06:18,820
Ilikuwa ni wale wote.

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00:06:18,820 --> 00:06:21,320
Hivyo moja tu kwamba ni upole
kuvutia ni moja kati.

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00:06:21,320 --> 00:06:24,700
Na kama wewe aina ya kufanya nje
math, utakuwa kuthibitisha kwamba, kwa kweli,

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00:06:24,700 --> 00:06:27,949
kwamba mfumo wa moja na
zeros inawakilisha 216.

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00:06:27,949 --> 00:06:30,240
Basi hebu tu inasema kwa
sasa kwamba hizi ni sahihi.

182
00:06:30,240 --> 00:06:31,730
Lakini kwa nini hii ni ya kuvutia?

183
00:06:31,730 --> 00:06:33,970
>> Naam, Byte, bila shaka, ni bits nane.

184
00:06:33,970 --> 00:06:38,980
Na zinageuka kuwa kama unadhani
ya Byte kama chunks wawili wa bits nne,

185
00:06:38,980 --> 00:06:39,500
kama hii.

186
00:06:39,500 --> 00:06:41,000
Napenda tu kuongeza baadhi ya nafasi.

187
00:06:41,000 --> 00:06:42,550
Basi, kabla ya, baada ya.

188
00:06:42,550 --> 00:06:46,520
Nimekuwa tu aliongeza baadhi ya nafasi nyeupe
kwa ajili visualization hapa.

189
00:06:46,520 --> 00:06:51,840
Jinsi gani sisi sasa kuwakilisha katika,
kusema, hexadecimal kila quad ya bits,

190
00:06:51,840 --> 00:06:52,880
kila seti ya bits nne?

191
00:06:52,880 --> 00:06:56,420
>> Hivyo kwa mfano, upande wa kushoto
sasa, tuna 1,111 katika binary.

192
00:06:56,420 --> 00:07:00,420
Je, ni kwamba idadi katika decimal,
kama wewe kufanya nje math?

193
00:07:00,420 --> 00:07:03,780
Una ndio mahali, wawili-wawili mahali,
fours mahali, na eights mahali.

194
00:07:03,780 --> 00:07:04,341
>> Watazamaji: 15.

195
00:07:04,341 --> 00:07:05,340
DAVID J. Malan: Ni 15.

196
00:07:05,340 --> 00:07:08,340
Hivyo kama sisi kufanya nane pamoja na nne
pamoja na mbili pamoja na moja, sisi kupata 15.

197
00:07:08,340 --> 00:07:11,790
Ili niweze kuandika 15 chini
1111, lakini hatua nzima hapa

198
00:07:11,790 --> 00:07:13,190
ni hexadecimal, si decimal.

199
00:07:13,190 --> 00:07:17,310
Hivyo badala ya kuandika 15, 1-5,
Mimi nina kwenda kuandika kwamba katika hex,

200
00:07:17,310 --> 00:07:22,311
ambayo kama wewe kufikiri nyuma, kama una
zero kupitia f, ni nini 15 kwenda kuwa?

201
00:07:22,311 --> 00:07:22,810
Watazamaji: f.

202
00:07:22,810 --> 00:07:24,434
DAVID J. Malan: Hivyo ni zamu nje ni ya f.

203
00:07:24,434 --> 00:07:29,140
Na unaweza kufanya kazi nje kwamba kwa kusema,
vizuri, kama ni 10, kisha OK, f ni 15.

204
00:07:29,140 --> 00:07:33,250
Hivyo kweli, tunaweza kuandika upya
kuweka hii moja ya namba kama f f.

205
00:07:33,250 --> 00:07:35,750
Na kisha kama sisi kufanya kidogo ya math,
tutaweza kuthibitisha kwamba hiyo ni d.

206
00:07:35,750 --> 00:07:38,650
Nane ni pretty rahisi, kwa sababu sisi
na moja katika eights mahali.

207
00:07:38,650 --> 00:07:40,620
Na kisha, sisi kuwa wanandoa zaidi f f ya.

208
00:07:40,620 --> 00:07:44,669
>> Basi nini binadamu huwa na kufanya kwa mkataba
wakati matumizi ya hexadecimal ni wao tu

209
00:07:44,669 --> 00:07:47,710
kuandika hii kidogo zaidi kwa ufupi,
kujikwamua zaidi ya nafasi ya kuwa nyeupe.

210
00:07:47,710 --> 00:07:50,890
Na tu kuwa super wazi kwa
wasomaji kwamba hii ni hexadecimal,

211
00:07:50,890 --> 00:07:54,670
mkataba kati ya rahisi
binadamu ni wewe kuandika zero

212
00:07:54,670 --> 00:07:58,000
x, ambayo haina maana nyingine
kuliko kitambulisho Visual ya,

213
00:07:58,000 --> 00:07:59,590
hiyo inakuja idadi hex.

214
00:07:59,590 --> 00:08:04,210
>> Na kisha, unaweza kuweka tarakimu mbili za, f
f katika kesi hii, basi d, basi f f.

215
00:08:04,210 --> 00:08:06,700
Hivyo hadithi muda mfupi,
hexadecimal tu huelekea

216
00:08:06,700 --> 00:08:11,990
kuwa na manufaa kwa sababu kila moja ya yake
tarakimu, sifuri kupitia f, kikamilifu mistari

217
00:08:11,990 --> 00:08:13,880
up na muundo wa bits nne.

218
00:08:13,880 --> 00:08:18,080
>> Hivyo kama una tarakimu hexadecimal mbili,
zero kupitia F, tena na tena,

219
00:08:18,080 --> 00:08:20,256
kwamba anatoa kikamilifu
bits nane au Byte moja.

220
00:08:20,256 --> 00:08:22,380
Hivyo ndiyo sababu inaelekea
kuwa conventionally muhimu.

221
00:08:22,380 --> 00:08:24,990
Hakuna miliki
maudhui kweli zaidi ya hapo,

222
00:08:24,990 --> 00:08:27,010
zaidi ya matumizi yake halisi.

223
00:08:27,010 --> 00:08:29,310
>> Sasa JPEGs ni si tu
faili format kwa graphics.

224
00:08:29,310 --> 00:08:33,230
Unaweza kukumbuka kwamba kuna
files kama hii katika dunia,

225
00:08:33,230 --> 00:08:34,830
angalau kutoka miaka michache nyuma.

226
00:08:34,830 --> 00:08:37,580
>> Hivyo hii ilikuwa kweli
imewekwa katika Windows XP

227
00:08:37,580 --> 00:08:39,960
juu ya mamilioni ya PC duniani kote.

228
00:08:39,960 --> 00:08:43,000
Na hii ilikuwa bitmap faili, BMP.

229
00:08:43,000 --> 00:08:47,690
Na bitmap faili, kama utaona ya
wiki, tu ina maana ya muundo wa dots,

230
00:08:47,690 --> 00:08:51,710
Ukubwa kama wao ni kuitwa,
a ramani juu ya bits, kwa kweli.

231
00:08:51,710 --> 00:08:55,160
>> Basi nini kuvutia, ingawa,
kuhusu hili format file, BMP, ni

232
00:08:55,160 --> 00:08:58,590
kwamba chini ya Hood, ni
ina zaidi ya ka tatu tu

233
00:08:58,590 --> 00:09:01,020
ambayo kutunga header yake, hivyo
kusema, kwanza kuumwa chache.

234
00:09:01,020 --> 00:09:03,330
Ni kweli inaonekana kidogo
ngumu katika mtazamo wa kwanza.

235
00:09:03,330 --> 00:09:04,704
Na utaona hili katika P kuweka.

236
00:09:04,704 --> 00:09:06,810
Na kupata kitu
nje fulani ya hii sasa

237
00:09:06,810 --> 00:09:10,720
si hivyo muhimu, kama tu ukweli
kuwa katika mwanzo wa kila bitmap

238
00:09:10,720 --> 00:09:13,823
file, format graphical,
kuna rundo zima wa idadi.

239
00:09:13,823 --> 00:09:14,980

240
00:09:14,980 --> 00:09:16,720
>> Sasa Microsoft,
mwandishi wa muundo huu,

241
00:09:16,720 --> 00:09:18,820
huelekea kuwaita wale
mambo si ints na chars

242
00:09:18,820 --> 00:09:22,259
na ikifungwa lakini maneno na d
maneno na anatamani na ka.

243
00:09:22,259 --> 00:09:23,800
Hivyo wao ni tu aina tofauti data.

244
00:09:23,800 --> 00:09:25,170
Wao ni majina tofauti
kwa kitu kimoja.

245
00:09:25,170 --> 00:09:26,740
Lakini utaona kwamba katika P Set Nne.

246
00:09:26,740 --> 00:09:31,450
>> Lakini hii ni tu kusema kwamba kama binadamu
mbili-Clicks baadhi ya faili .bmp upande wake

247
00:09:31,450 --> 00:09:35,015
au gari yake kwa bidii, na dirisha kuufungua
up kuonyesha kwake picha kwamba,

248
00:09:35,015 --> 00:09:38,500
kwamba kilichotokea kwa sababu uendeshaji
mfumo labda niliona si tu

249
00:09:38,500 --> 00:09:41,460
.bmp Faili ugani
katika jina la faili,

250
00:09:41,460 --> 00:09:45,010
lakini pia ni ukweli kwamba kuna baadhi ya
mkataba kwa mfano wa bits

251
00:09:45,010 --> 00:09:47,490
mwanzoni sana
ya kwamba bitmap faili.

252
00:09:47,490 --> 00:09:50,270
>> Lakini hebu sasa kuzingatia
kama faili ngumu,

253
00:09:50,270 --> 00:09:52,120
lakini badala yake juu ya kitu kama hiki.

254
00:09:52,120 --> 00:09:55,190
Tuseme hapa katika gedit, mimi
tu mwanzo

255
00:09:55,190 --> 00:09:57,070
wa mpango huo pretty rahisi.

256
00:09:57,070 --> 00:09:58,860
Mimi nimepata baadhi ni pamoja na juu juu.

257
00:09:58,860 --> 00:10:02,120
Sasa mimi nimepata #include "structs.h" lakini
Mimi itabidi kuja nyuma na kwamba katika wakati huu.

258
00:10:02,120 --> 00:10:03,974
Lakini hii ni muhimu kwa sasa.

259
00:10:03,974 --> 00:10:05,890
Hivyo hii ni mpango
hiyo ni kwenda kutekeleza

260
00:10:05,890 --> 00:10:07,335
kama database msajili ya.

261
00:10:07,335 --> 00:10:09,710
Hivyo database ya wanafunzi,
na kila mwanafunzi katika dunia

262
00:10:09,710 --> 00:10:13,190
ina jina na nyumba na pengine baadhi ya
mambo mengine, lakini tutaweza kushika ni rahisi.

263
00:10:13,190 --> 00:10:15,140
Kila mwanafunzi ana jina na nyumba.

264
00:10:15,140 --> 00:10:17,700
>> Hivyo kama mimi alitaka kuandika
mpango ambao lengo katika maisha

265
00:10:17,700 --> 00:10:19,860
mara tu iterate kutoka
sifuri juu ya hadi tatu,

266
00:10:19,860 --> 00:10:22,070
kama kuna wanafunzi watatu
katika Chuo Kikuu cha Harvard.

267
00:10:22,070 --> 00:10:25,350
Na mimi nataka tu kupata, kwa kutumia GetString,
jina la kila mwanafunzi na nyumba,

268
00:10:25,350 --> 00:10:26,600
na kisha tu magazeti wale nje.

269
00:10:26,600 --> 00:10:28,630
>> Hii ni aina ya kama Wiki
Moja, Wiki Barua mambo sasa,

270
00:10:28,630 --> 00:10:30,810
ambapo mimi nataka tu kwa
kitanzi au kitu kama hicho.

271
00:10:30,810 --> 00:10:34,500
Na mimi nataka kuwaita GetString chache
mara kwa mara, na kisha magazeti f mara chache.

272
00:10:34,500 --> 00:10:37,340
Hivyo jinsi gani mimi kufanya hivyo, ingawa,
wakati wote jina na nyumba

273
00:10:37,340 --> 00:10:39,070
ni kushiriki kwa kila mwanafunzi?

274
00:10:39,070 --> 00:10:42,830
>> Hivyo silika yangu ya kwanza nguvu
kuwa kufanya kitu kama hiki.

275
00:10:42,830 --> 00:10:49,620
Mimi anaweza kusema kwanza, vizuri, nipe,
kusema, safu ya masharti kuitwa majina.

276
00:10:49,620 --> 00:10:51,530
Na sitaki hardcode tatu hapa.

277
00:10:51,530 --> 00:10:53,064
Nini nataka kuweka huko?

278
00:10:53,064 --> 00:10:55,730
Hivyo WANAFUNZI, kwa sababu hiyo tu
mara kwa mara alitangaza saa ya juu,

279
00:10:55,730 --> 00:10:57,860
hivyo tu sina kwa hardcode
tatu katika maeneo mbalimbali.

280
00:10:57,860 --> 00:11:00,859
Kwa njia hii, siwezi mabadiliko hayo sehemu moja,
na huathiri mabadiliko kila mahali.

281
00:11:00,859 --> 00:11:04,470
Na kisha, mimi ili kufanya
kamba nyumba WANAFUNZI.

282
00:11:04,470 --> 00:11:10,250
>> Na sasa, mimi ili kufanya kitu kama
kwa (int i = 0; i <WANAFUNZI; i ++.

283
00:11:10,250 --> 00:11:14,390
Hivyo mimi nina kuandika haraka, lakini hii ni
pengine familiar syntax sasa.

284
00:11:14,390 --> 00:11:17,030
>> Na sasa, hii ilikuwa zaidi ya hivi karibuni.

285
00:11:17,030 --> 00:11:22,890
Kama mimi nataka kuweka katika i-th
jina mwanafunzi, mimi nadhani kufanya hivyo.

286
00:11:22,890 --> 00:11:26,480
Na kisha, si majina
lakini nyumba mabano i.

287
00:11:26,480 --> 00:11:29,930
Mimi kufanya hivyo, GetString, na basi
mimi kwenda nyuma na kurekebisha mstari huu.

288
00:11:29,930 --> 00:11:30,430
Kukubaliana?

289
00:11:30,430 --> 00:11:31,200
Hawakubaliani?

290
00:11:31,200 --> 00:11:32,366
Siyo sana user-kirafiki.

291
00:11:32,366 --> 00:11:33,890
Sikumwambia user nini cha kufanya.

292
00:11:33,890 --> 00:11:36,520
>> Lakini sasa, kama mimi pia
alitaka baadaye, hebu

293
00:11:36,520 --> 00:11:40,060
kusema, magazeti hayo
out-- hivyo TODO baadaye.

294
00:11:40,060 --> 00:11:42,330
Mimi nina kwenda kufanya zaidi na
Haya hii arguably yaani

295
00:11:42,330 --> 00:11:45,970
utekelezaji sahihi ya
kupata majina na nyumba, tatu

296
00:11:45,970 --> 00:11:48,870
wao jumla ya kila mmoja, kutoka kwa mtumiaji.

297
00:11:48,870 --> 00:11:51,280
>> Lakini hii si nzuri sana kubuni, haki?

298
00:11:51,280 --> 00:11:55,220
Nini kama mwanafunzi ana si tu jina
na nyumba, lakini pia ID ya simu,

299
00:11:55,220 --> 00:11:57,770
na namba ya simu,
na barua pepe,

300
00:11:57,770 --> 00:12:00,280
na labda ukurasa wa nyumbani, na
labda Twitter kushughulikia,

301
00:12:00,280 --> 00:12:03,730
na idadi yoyote ya maelezo mengine
kuhusishwa na mwanafunzi au mtu,

302
00:12:03,730 --> 00:12:04,610
ujumla zaidi.

303
00:12:04,610 --> 00:12:07,720
Jinsi gani sisi kuanza kuongeza
utendaji kwa mpango huu?

304
00:12:07,720 --> 00:12:14,080
>> Naam, mimi najisikia kama njia rahisi nguvu
kuwa kufanya kitu kama, hebu sema,

305
00:12:14,080 --> 00:12:16,490
int Vitambulisho WANAFUNZI.

306
00:12:16,490 --> 00:12:18,380
Hivyo siwezi kuweka vitambulisho yao yote huko.

307
00:12:18,380 --> 00:12:22,240
Na kisha, kwa ajili ya kitu
kama namba za simu,

308
00:12:22,240 --> 00:12:24,400
Mimi nina uhakika jinsi ya
kuwakilisha kwamba bado tu.

309
00:12:24,400 --> 00:12:30,280
Basi hebu kwenda mbele na wito tu
hii Twitters WANAFUNZI, ambayo

310
00:12:30,280 --> 00:12:33,550
ni ajabu kidogo, but--
na rundo mashamba zaidi.

311
00:12:33,550 --> 00:12:36,360
>> Nimeanza kwa ufanisi
nakala na kuweka hapa.

312
00:12:36,360 --> 00:12:39,416
Na hii ni kwenda kukua pretty
unwieldy pretty haraka, haki?

313
00:12:39,416 --> 00:12:42,290
Je, si ni kuwa nzuri kama kulikuwa na
katika dunia muundo data inayojulikana

314
00:12:42,290 --> 00:12:45,600
si kama int au kamba, lakini kitu
ngazi ya juu, kufikirika, hivyo

315
00:12:45,600 --> 00:12:47,570
kusema, unaojulikana kama mwanafunzi?

316
00:12:47,570 --> 00:12:50,220
C hakuwa kuja na kujengwa katika
utendaji kwa ajili ya wanafunzi,

317
00:12:50,220 --> 00:12:52,260
lakini nini kama mimi alitaka kuwapa hizo?

318
00:12:52,260 --> 00:12:55,640
>> Naam, ni zamu nje, mimi nina kwenda
kufungua faili inayoitwa structs.h hapa,

319
00:12:55,640 --> 00:12:57,090
na unaweza kufanya hasa kwamba.

320
00:12:57,090 --> 00:12:58,290
Na sisi ni kwenda kuanza kufanya hivi sasa.

321
00:12:58,290 --> 00:13:01,490
Na chini ya Hood ya P Set ya Tatu,
umefanya tayari kufanya hivyo sasa.

322
00:13:01,490 --> 00:13:05,920
Hakuna kitu kama vile g rect ni au
g mviringo katika lugha ya programu C.

323
00:13:05,920 --> 00:13:10,570
>> Folks katika Stanford kutekelezwa wale
aina data kwa kutumia mbinu hii hapa,

324
00:13:10,570 --> 00:13:13,900
kutangaza yao wenyewe data mpya
aina kutumia keyword mpya

325
00:13:13,900 --> 00:13:16,744
kuitwa struct na mwingine
mtu mmoja aitwaye typedef.

326
00:13:16,744 --> 00:13:19,660
Na hakika, hata kama syntax
inaonekana tofauti kidogo kutoka kwa mambo

327
00:13:19,660 --> 00:13:23,550
tumeona kabla, katika
Kimsingi, ni super rahisi.

328
00:13:23,550 --> 00:13:25,297
>> Hii ina maana "kufafanua aina."

329
00:13:25,297 --> 00:13:27,255
Hiyo inaenda kuwa
muundo, na muundo

330
00:13:27,255 --> 00:13:29,400
ni tu kama chombo
kwa ajili ya mambo mbalimbali.

331
00:13:29,400 --> 00:13:31,780
Na muundo kwamba ni kwenda
kuwa na string kuitwa jina,

332
00:13:31,780 --> 00:13:33,210
na string kuitwa nyumba.

333
00:13:33,210 --> 00:13:37,520
Na hebu kuwaita, tu kwa urahisi,
muundo data hii yote mwanafunzi.

334
00:13:37,520 --> 00:13:40,320
>> Hivyo wakati wewe kupata
semicolon, una sasa

335
00:13:40,320 --> 00:13:43,280
kuundwa data yako mwenyewe
aina kuitwa mwanafunzi

336
00:13:43,280 --> 00:13:46,420
kwamba sasa anasimama sambamba int,
na kuelea, na char, na kamba,

337
00:13:46,420 --> 00:13:50,270
na g rect, na g mviringo, na idadi yoyote
ya mambo mengine watu kuwa wakiyazua.

338
00:13:50,270 --> 00:13:53,340
>> Basi nini muhimu kuhusu hii
sasa ni kwamba kama mimi kwenda nyuma

339
00:13:53,340 --> 00:13:57,430
kwa struct 0 na kumaliza hii
utekelezaji, ambayo niliandika

340
00:13:57,430 --> 00:14:02,080
mapema hapa, taarifa kwamba wote
ya messiness kuepukika kwamba

341
00:14:02,080 --> 00:14:05,490
ilikuwa juu ya kuanza kinachotokea kama mimi aliongeza
namba za simu na Twitters na wote

342
00:14:05,490 --> 00:14:07,370
mambo haya mengine kwa
mwanafunzi ufafanuzi,

343
00:14:07,370 --> 00:14:11,810
sasa ni ufupi ilimalizika
kama safu moja tu ya wanafunzi.

344
00:14:11,810 --> 00:14:15,500
>> Na kila mmoja wa wanafunzi hao sasa
ina mambo mbalimbali ndani yake.

345
00:14:15,500 --> 00:14:16,930
Hivyo kwamba tu majani swali moja.

346
00:14:16,930 --> 00:14:19,700
Jinsi gani unaweza kupata katika jina,
na nyumba, na ID,

347
00:14:19,700 --> 00:14:21,640
chochote ambacho ni
ndani ya mwanafunzi?

348
00:14:21,640 --> 00:14:22,930
Super rahisi, kama vile.

349
00:14:22,930 --> 00:14:25,730
New syntax, lakini wazo rahisi.

350
00:14:25,730 --> 00:14:29,239
>> Wewe tu index katika safu,
kama tulivyofanya wiki iliyopita na hii.

351
00:14:29,239 --> 00:14:31,030
Na nini wazi
kipande mpya ya syntax?

352
00:14:31,030 --> 00:14:32,590

353
00:14:32,590 --> 00:14:35,880
Tu., Ambayo ina maana ya "kwenda ndani
muundo na kupata shamba iitwayo

354
00:14:35,880 --> 00:14:39,030
jina, kupata shamba iitwayo nyumba,
kupata shamba iitwayo mwanafunzi. "

355
00:14:39,030 --> 00:14:41,940
>> Hivyo katika P Set Tatu, kama wewe ni
bado kazi hiyo,

356
00:14:41,940 --> 00:14:44,020
na folks wengi bado
ni, kutambua kwamba kama wewe

357
00:14:44,020 --> 00:14:46,130
kuanza kutumia vitu kama
g rects na g ovals

358
00:14:46,130 --> 00:14:50,201
na mambo mengine ambayo hawaonekani
kuja kutoka Wiki Zero, One, au mbili,

359
00:14:50,201 --> 00:14:52,950
kutambua kwamba hiyo ni kwa sababu Stanford
alitangaza baadhi ya aina mpya data.

360
00:14:52,950 --> 00:14:56,160
>> Na hakika, hiyo ni nini hasa sisi itabidi
kufanya, kama vile, katika P Set Nne, wakati

361
00:14:56,160 --> 00:14:59,880
sisi kuanza kukabiliana na mambo
kama picha, bitmaps, na zaidi.

362
00:14:59,880 --> 00:15:02,882
Hivyo hiyo ni teaser na
mfano wa akili kwa nini kuja.

363
00:15:02,882 --> 00:15:04,590
Sasa, mimi procrastinated
kidogo asubuhi hii.

364
00:15:04,590 --> 00:15:09,560
Mimi nilikuwa aina ya curious kuona nini
Karatasi ya Microsoft kweli

365
00:15:09,560 --> 00:15:10,310
inaonekana kama leo.

366
00:15:10,310 --> 00:15:15,200
Na zinageuka mtu mwaka 2006
kweli alikwenda karibu just

367
00:15:15,200 --> 00:15:19,210
doa huo kupiga picha katika hali halisi
kile kinachoonekana kama kwamba siku hizi.

368
00:15:19,210 --> 00:15:21,380
shamba ni sasa kidogo iliyojitokeza.

369
00:15:21,380 --> 00:15:24,850
>> Hivyo akizungumza sasa wa picha,
hebu kuleta nyuma Daven hapa

370
00:15:24,850 --> 00:15:26,890
juu ya screen na Nicholas,
na tu kuwakumbusha

371
00:15:26,890 --> 00:15:30,540
kwamba kama wewe Ningependa kujiunga na sisi kwa chakula cha mchana
Ijumaa hii, kichwa na kawaida URL yetu

372
00:15:30,540 --> 00:15:31,440
hapa.

373
00:15:31,440 --> 00:15:33,530
>> Hivyo ambapo gani sisi kuondoka mbali juu ya Jumatatu?

374
00:15:33,530 --> 00:15:35,140
Sisi ilianzisha tatizo hili, haki?

375
00:15:35,140 --> 00:15:37,610
Hii ilikuwa inaonekana sahihi
utekelezaji wa wabadilishane,

376
00:15:37,610 --> 00:15:40,460
ambapo wewe kuchukua ints mbili,
mtu mmoja aitwaye, na mtu mmoja aitwaye b,

377
00:15:40,460 --> 00:15:44,130
wabadilishane yao, kama alivyofanya Laura hapa
juu ya hatua kwa maziwa na maji,

378
00:15:44,130 --> 00:15:46,820
kwa kutumia muda
variable, au kikombe tupu,

379
00:15:46,820 --> 00:15:50,540
ili tuweze kuweka b katika na katika
b bila kufanya fujo ya mambo.

380
00:15:50,540 --> 00:15:51,560
Sisi kutumika kutofautiana.

381
00:15:51,560 --> 00:15:52,870
Ni wito temp.

382
00:15:52,870 --> 00:15:55,520
>> Lakini kile ambacho kilikuwa msingi
tatizo na kanuni hii juu ya Jumatatu?

383
00:15:55,520 --> 00:15:57,700

384
00:15:57,700 --> 00:15:58,870
Na tatizo hapa ni nini?

385
00:15:58,870 --> 00:16:00,106

386
00:16:00,106 --> 00:16:00,605
Yeah.

387
00:16:00,605 --> 00:16:01,970
>> Watazamaji: Ni inachukua hadi nafasi zaidi.

388
00:16:01,970 --> 00:16:04,719
>> DAVID J. Malan: Inachukua hadi zaidi
nafasi, kwa sababu mimi nina kutumia variable,

389
00:16:04,719 --> 00:16:05,400
na kwamba ni sawa.

390
00:16:05,400 --> 00:16:07,300
Hiyo ni kweli, lakini mimi nina
kwenda kusema kwamba ni sawa.

391
00:16:07,300 --> 00:16:10,030
Ni bits 32 tu katika grand
mpango wa mambo, hivyo si kubwa mpango huo.

392
00:16:10,030 --> 00:16:10,655
Mawazo mengine?

393
00:16:10,655 --> 00:16:12,572
Watazamaji: Ni tu swaps
vigezo ndani ya nchi.

394
00:16:12,572 --> 00:16:13,571
DAVID J. Malan: Hasa.

395
00:16:13,571 --> 00:16:15,090
Ni tu swaps vigezo ndani ya nchi.

396
00:16:15,090 --> 00:16:18,173
Kwa sababu wakati wowote wewe piga function--
wakati nilikuwa trays kutoka Annenberg

397
00:16:18,173 --> 00:16:19,840
mara ya mwisho, una kuu juu ya chini.

398
00:16:19,840 --> 00:16:23,560
Haraka kama wewe piga kazi kuitwa
wabadilishane, wabadilishane haina kupata x na y,

399
00:16:23,560 --> 00:16:24,400
awali maadili.

400
00:16:24,400 --> 00:16:26,392
Je wabadilishane kupata, hatukufanya kudai?

401
00:16:26,392 --> 00:16:27,100
Watazamaji: Nakala.

402
00:16:27,100 --> 00:16:28,090
DAVID J. Malan: Hivyo nakala yao.

403
00:16:28,090 --> 00:16:31,120
Hivyo anapata moja na mbili, kama wewe
kukumbuka mfano kutoka wakati wa mwisho,

404
00:16:31,120 --> 00:16:34,730
lakini nakala ya moja na mbili
kwamba ni mafanikio swapped.

405
00:16:34,730 --> 00:16:38,550
Lakini kwa bahati mbaya katika mwisho,
maadili hayo bado ni sawa.

406
00:16:38,550 --> 00:16:41,880
Ili tuweze kuona hii na yetu
rafiki mpya, hopefully GDB,

407
00:16:41,880 --> 00:16:45,180
kwamba wewe au TFS na Ca ya kuwa na
wamekuwa kuongoza wewe kuelekea kama ifuatavyo.

408
00:16:45,180 --> 00:16:51,210
>> Hivyo hakuna kukumbuka wabadilishane inaonekana like-- hebu
kufungua Haya inaonekana kama hii.

409
00:16:51,210 --> 00:16:54,160
Sisi initialized x kwa moja, y miwili.

410
00:16:54,160 --> 00:16:55,620
Rundo la magazeti f ya.

411
00:16:55,620 --> 00:16:58,080
Lakini basi, kitufe cha kupiga simu
hapa ilikuwa wabadilishane, ambayo

412
00:16:58,080 --> 00:17:00,260
ni hasa code sisi
tu kuona wakati iliyopita.

413
00:17:00,260 --> 00:17:03,180
Ambayo ni sahihi kwa mara ya kwanza
mtazamo, lakini functionally,

414
00:17:03,180 --> 00:17:06,800
mpango huu hana kazi, kwa sababu
haina kudumu wabadilishane x na y.

415
00:17:06,800 --> 00:17:10,190
>> Basi hebu angalia hii, joto haraka
up hapa na GDB, ./noswap.

416
00:17:10,190 --> 00:17:11,867

417
00:17:11,867 --> 00:17:15,200
rundo la habari mno kwamba
Mimi itabidi kujikwamua na Kudhibiti L kwa sasa.

418
00:17:15,200 --> 00:17:17,516
Na sasa, mimi nina kwenda
kwenda mbele na kukimbia nayo.

419
00:17:17,516 --> 00:17:19,349
Na kwa bahati mbaya, kwamba
sio kwamba muhimu.

420
00:17:19,349 --> 00:17:22,355
Ni mbio mpango ndani ya hii
programu inayoitwa GDB, HatiJava,

421
00:17:22,355 --> 00:17:23,730
lakini hakuwa na napenda poke kuzunguka.

422
00:17:23,730 --> 00:17:26,229
>> Hivyo ni jinsi gani mimi kwa kweli pause
utekelezaji ndani ya mpango huu?

423
00:17:26,229 --> 00:17:27,410

424
00:17:27,410 --> 00:17:28,329
Hivyo mapumziko.

425
00:17:28,329 --> 00:17:32,340
Na mimi naweza kuvunja juu ya yoyote
line ya simu, moja, 10, 15.

426
00:17:32,340 --> 00:17:35,530
Lakini siwezi pia kuvunja mfano
kwa kusema mapumziko kuu.

427
00:17:35,530 --> 00:17:38,980
Na kwamba ni kwenda kuweka mapumziko
uhakika, inaonekana katika mstari 16 katika kuu.

428
00:17:38,980 --> 00:17:40,050
Na ambapo ni mstari 16?

429
00:17:40,050 --> 00:17:42,960
Hebu kwenda hadi code
na kwenda hadi noswap.

430
00:17:42,960 --> 00:17:46,930
Na hakika, line 16 ni
sana kwanza katika mpango.

431
00:17:46,930 --> 00:17:52,130
>> Hivyo sasa, kama mimi kwenda mbele na aina
kukimbia wakati huu, kuingia, ni paused.

432
00:17:52,130 --> 00:17:53,080
Basi hebu poke kuzunguka.

433
00:17:53,080 --> 00:17:55,716
Magazeti x-- kwa nini ni x sifuri?

434
00:17:55,716 --> 00:17:56,705

435
00:17:56,705 --> 00:17:57,830
Na kupuuza ishara ya dola.

436
00:17:57,830 --> 00:17:59,725
Hiyo tu kwa fancier
matumizi ya mpango huo.

437
00:17:59,725 --> 00:18:00,780

438
00:18:00,780 --> 00:18:03,140
Kwa nini ni x sifuri wakati huu?

439
00:18:03,140 --> 00:18:03,640
Yeah.

440
00:18:03,640 --> 00:18:07,061
>> Watazamaji: Ni paused haki kabla ya
mstari 16, si kweli juu ya mstari 16.

441
00:18:07,061 --> 00:18:08,060
DAVID J. Malan: Hasa.

442
00:18:08,060 --> 00:18:11,630
GDB, by default, ina paused
utekelezaji tu kabla ya mstari 16.

443
00:18:11,630 --> 00:18:14,820
Hivyo ina haitekelezwi, ambayo
ina maana x ni ya baadhi ya thamani haijulikani.

444
00:18:14,820 --> 00:18:17,150
Na sisi got bahati kwamba ni
kitu safi kama sifuri.

445
00:18:17,150 --> 00:18:20,310
Hivyo sasa kama mimi aina ya pili,
sasa ni kunyongwa 16.

446
00:18:20,310 --> 00:18:22,000
Ni kusubiri kwa ajili yangu na nitafanya 17.

447
00:18:22,000 --> 00:18:23,400
Hebu kwenda mbele na magazeti x.

448
00:18:23,400 --> 00:18:24,094
Ni moja.

449
00:18:24,094 --> 00:18:25,260
Hebu kwenda mbele na magazeti y.

450
00:18:25,260 --> 00:18:26,176
Nifanye kuona sasa?

451
00:18:26,176 --> 00:18:27,660

452
00:18:27,660 --> 00:18:28,560
>> Watazamaji: [inaudible]

453
00:18:28,560 --> 00:18:29,165
>> DAVID J. Malan: sauti kidogo.

454
00:18:29,165 --> 00:18:30,040
>> Watazamaji: [inaudible]

455
00:18:30,040 --> 00:18:30,537

456
00:18:30,537 --> 00:18:32,120
DAVID J. Malan: Si kabisa makubaliano.

457
00:18:32,120 --> 00:18:34,760
Hivyo ndiyo, sisi kuona baadhi ya thamani ya takataka.

458
00:18:34,760 --> 00:18:37,862
Sasa, y ni 134514064 huko.

459
00:18:37,862 --> 00:18:39,320
Naam, ni baadhi tu ya thamani ya takataka.

460
00:18:39,320 --> 00:18:41,350
Mpango wangu anatumia RAM
kwa malengo tofauti.

461
00:18:41,350 --> 00:18:42,350
Kuna kazi nyingine.

462
00:18:42,350 --> 00:18:44,040
Watu wengine aliandika ndani ya kompyuta yangu.

463
00:18:44,040 --> 00:18:46,789
Hivyo bits wale wamekuwa kutumika kwa ajili ya
maadili mengine, na kile Mimi nina kuona

464
00:18:46,789 --> 00:18:49,470
ni mabaki ya baadhi
matumizi kabla ya kuwa kumbukumbu.

465
00:18:49,470 --> 00:18:53,350
>> Hivyo hakuna mpango mkubwa, kwa sababu kama hivi karibuni
kama mimi aina ya pili na kisha magazeti y,

466
00:18:53,350 --> 00:18:55,640
ni initialized kwa
thamani kwamba mimi nataka.

467
00:18:55,640 --> 00:18:57,400
Hivyo sasa, hebu kwenda mbele kasi kidogo.

468
00:18:57,400 --> 00:18:58,540
N kwa ajili ya pili.

469
00:18:58,540 --> 00:18:59,570
Hebu kufanya hivyo tena.

470
00:18:59,570 --> 00:19:00,530
Hebu kufanya hivyo tena.

471
00:19:00,530 --> 00:19:02,404
Lakini mimi si unataka hit
hapa, kwa sababu kama mimi

472
00:19:02,404 --> 00:19:05,110
wanataka kuona nini kinaendelea ndani ya
ya wabadilishane, nini amri?

473
00:19:05,110 --> 00:19:05,520
>> Watazamaji: hatua.

474
00:19:05,520 --> 00:19:06,436
>> DAVID J. Malan: hatua.

475
00:19:06,436 --> 00:19:09,800
Hivyo hii hatua yangu ndani ya
kazi, badala ya juu yake.

476
00:19:09,800 --> 00:19:12,270
Na sasa, ni kidogo cryptic
uaminifu, lakini hii ni

477
00:19:12,270 --> 00:19:14,581
kuniambia mimi nina katika line 33 sasa.

478
00:19:14,581 --> 00:19:15,580
Na hebu kufanya hii tena.

479
00:19:15,580 --> 00:19:16,080
Print temp.

480
00:19:16,080 --> 00:19:17,129

481
00:19:17,129 --> 00:19:20,170
Takataka thamani, hasi wakati huu,
lakini hiyo ni bado thamani ya takataka.

482
00:19:20,170 --> 00:19:22,810
Basi hebu kufanya ijayo, magazeti temp.

483
00:19:22,810 --> 00:19:27,130
Ni initialized kwa 1, ambayo
Ilikuwa thamani ya x, aka.

484
00:19:27,130 --> 00:19:29,110
>> Sasa, ambapo ni a wetu na X kuja kutoka?

485
00:19:29,110 --> 00:19:32,510
Naam, taarifa katika kuu, sisi
kuitwa maadili haya x na y.

486
00:19:32,510 --> 00:19:34,740
Sisi basi kupita yao wabadilishane kama ifuatavyo.

487
00:19:34,740 --> 00:19:37,010
X alikuja kwanza, comma y.

488
00:19:37,010 --> 00:19:40,020
Na kisha, wabadilishane inaweza kuwaita x na y.

489
00:19:40,020 --> 00:19:42,630
Lakini kwa uwazi, ni
kuwaita na b.

490
00:19:42,630 --> 00:19:45,970
Lakini a na b ni sasa kwenda kuwa
nakala za x na y, kwa mtiririko huo.

491
00:19:45,970 --> 00:19:50,660
>> Hivyo kama mimi kurejea GDB, temp
sasa ni moja na sasa ni moja.

492
00:19:50,660 --> 00:19:56,130
Lakini kama mimi kufanya ijayo na sasa kufanya magazeti
a, a tayari wakiongozwa juu.

493
00:19:56,130 --> 00:20:00,030
maziwa amekwisha miminia wa zamani
kioo juisi ya machungwa, au kinyume chake.

494
00:20:00,030 --> 00:20:04,750
>> Na kama mimi kufanya ijayo tena, na sasa
kama mimi magazeti nje kama sanity hundi,

495
00:20:04,750 --> 00:20:07,687
a ni bado mbili, lakini b ni sasa moja.

496
00:20:07,687 --> 00:20:08,770
Kwa kweli, bado kuna.

497
00:20:08,770 --> 00:20:10,670
Mimi sijali nini temp ni.

498
00:20:10,670 --> 00:20:16,850
Lakini kwa haraka kama mimi sasa aina, hebu sema,
kuendelea kwenda nyuma, sasa mimi nina mwishoni mwa

499
00:20:16,850 --> 00:20:17,480
mpango.

500
00:20:17,480 --> 00:20:20,730
Na kwa bahati mbaya, x ni
bado moja na y ni bado mbili.

501
00:20:20,730 --> 00:20:22,272
>> Hivyo kile alikuwa matumizi ya GDB huko?

502
00:20:22,272 --> 00:20:23,980
Ni hakuwa na msaada kwangu kurekebisha
tatizo per se,

503
00:20:23,980 --> 00:20:26,265
lakini hopefully kusaidia mimi
kuelewa ni kwa kutambua

504
00:20:26,265 --> 00:20:30,000
kwamba ndiyo, mantiki yangu ni ya haki, lakini
code yangu si hatimaye kuwa

505
00:20:30,000 --> 00:20:31,450
athari ya kudumu.

506
00:20:31,450 --> 00:20:34,570
Hivyo hiyo ni tatizo sisi ni
kwenda sasa kutatua leo.

507
00:20:34,570 --> 00:20:37,870
>> Lakini hebu kupata huko kwa njia ya hii.

508
00:20:37,870 --> 00:20:39,230
String ni uongo.

509
00:20:39,230 --> 00:20:41,860
Yake, pia, si aina data
kwamba ipo katika C. Ni

510
00:20:41,860 --> 00:20:44,750
imekuwa kisawe kwa baadhi
muda kwa ajili ya kitu kingine,

511
00:20:44,750 --> 00:20:47,300
na tunaweza yanaonyesha kwamba kama ifuatavyo.

512
00:20:47,300 --> 00:20:53,282
>> Hebu kwenda mbele na kufungua
mpango aitwaye kulinganisha-0.

513
00:20:53,282 --> 00:20:56,240
Na badala ya aina hii moja nje,
tutaweza kuanza kutembea kwa njia ya code

514
00:20:56,240 --> 00:20:58,040
Mimi tayari aliandika, lakini
ni tu mistari michache.

515
00:20:58,040 --> 00:20:59,570
Hivyo hii ni kulinganisha-0.

516
00:20:59,570 --> 00:21:02,380
Na jambo la kwanza mimi nina kufanya
ni kupata mstari wa maandishi.

517
00:21:02,380 --> 00:21:05,610
>> Lakini taarifa ya nini mimi nina
kufanya kwa mara ya kwanza.

518
00:21:05,610 --> 00:21:07,910
Nini ni tofauti kwa uwazi juu ya line 21?

519
00:21:07,910 --> 00:21:10,020

520
00:21:10,020 --> 00:21:11,402
Kwa kweli, kusubiri dakika.

521
00:21:11,402 --> 00:21:12,110
Hii ni nakala mbili.

522
00:21:12,110 --> 00:21:13,568
Hilo wala siyo hata mpango wa haki.

523
00:21:13,568 --> 00:21:14,780
Haki zote, spoiler tahadhari.

524
00:21:14,780 --> 00:21:16,890
Haki zote, hivyo kamwe akili kwamba.

525
00:21:16,890 --> 00:21:18,520
Hiyo ni jibu la swali siku zijazo.

526
00:21:18,520 --> 00:21:21,450
>> Hapa ni kulinganisha-0, na mimi nina
kuhusu kupata mstari wa maandishi.

527
00:21:21,450 --> 00:21:22,435
Programu ya rahisi sana.

528
00:21:22,435 --> 00:21:23,560
Hivyo hii ni moja kwa moja.

529
00:21:23,560 --> 00:21:28,070
Hii ni kama wiki moja, Wiki Barua mambo
wakati huu. kamba s = GetString.

530
00:21:28,070 --> 00:21:29,700
Sasa, mimi kusema tena hapa chini.

531
00:21:29,700 --> 00:21:31,830
kamba t = GetString.

532
00:21:31,830 --> 00:21:35,300
Na kisha, jambo la mwisho katika hii
mpango, kama jina lake anapendekeza,

533
00:21:35,300 --> 00:21:37,090
ni mimi nina kwenda kujaribu kulinganisha yao.

534
00:21:37,090 --> 00:21:40,709
>> Hivyo kama s, kamba ya kwanza,
sawa na t =, basi mimi nina

535
00:21:40,709 --> 00:21:42,250
kwenda kusema wewe aina kitu kimoja.

536
00:21:42,250 --> 00:21:44,291
Kingine, mimi nina kwenda kusema
unapoandika mambo mbalimbali.

537
00:21:44,291 --> 00:21:45,880
Basi hebu kukusanya na kukimbia mpango huu.

538
00:21:45,880 --> 00:21:48,481
Hivyo kufanya kulinganisha sifuri.

539
00:21:48,481 --> 00:21:48,980
Inaonekana nzuri.

540
00:21:48,980 --> 00:21:50,490
Hakuna makosa mkusanyiko.

541
00:21:50,490 --> 00:21:52,386
>> Hebu kwenda mbele sasa
na aina ./compare-0.

542
00:21:52,386 --> 00:21:55,230

543
00:21:55,230 --> 00:21:59,220
Hebu kwenda mbele na kusema kitu
: Daven na kitu: Rob.

544
00:21:59,220 --> 00:22:00,450
Na mimi aina ya mambo mbalimbali.

545
00:22:00,450 --> 00:22:01,250
Hadi sasa, hivyo nzuri.

546
00:22:01,250 --> 00:22:02,680
Programu inaonekana kuwa sahihi.

547
00:22:02,680 --> 00:22:03,880
>> Lakini hebu kukimbia tena.

548
00:22:03,880 --> 00:22:05,800
Sema kitu: Gabe.

549
00:22:05,800 --> 00:22:07,140
Sema kitu: Gabe.

550
00:22:07,140 --> 00:22:08,520

551
00:22:08,520 --> 00:22:09,020
Wote haki.

552
00:22:09,020 --> 00:22:10,851
Labda mimi hit nafasi bar
au kitu funky.

553
00:22:10,851 --> 00:22:11,600
Hebu kufanya hivyo tena.

554
00:22:11,600 --> 00:22:13,020
Hivyo Zamyla.

555
00:22:13,020 --> 00:22:13,970

556
00:22:13,970 --> 00:22:14,470
Zamyla.

557
00:22:14,470 --> 00:22:15,740

558
00:22:15,740 --> 00:22:17,330
Mambo mbalimbali.

559
00:22:17,330 --> 00:22:19,430
Hivyo ni nini kinaendelea?

560
00:22:19,430 --> 00:22:23,200
>> Hivyo tuna mistari hizi mbili za
code, GetString kuitwa mara mbili.

561
00:22:23,200 --> 00:22:25,760
Na kisha, mimi nina tu
kujaribu kulinganisha s na t.

562
00:22:25,760 --> 00:22:28,370
Lakini nini kweli basi kinachoendelea?

563
00:22:28,370 --> 00:22:31,180
Naam, handwriting yangu kuhusu
kuwaueni mfano huu kwa kiasi fulani.

564
00:22:31,180 --> 00:22:34,630
Na hebu kweli kutupa
hii up juu ya hapa, kama vile.

565
00:22:34,630 --> 00:22:37,390

566
00:22:37,390 --> 00:22:45,712
>> Hivyo tuna line kama
kamba s = GetString.

567
00:22:45,712 --> 00:22:48,295
Hivyo kwamba ni tu kwanza
kuvutia line kutoka mpango huo.

568
00:22:48,295 --> 00:22:49,920

569
00:22:49,920 --> 00:22:52,974
Lakini nini wakati huu wote imekuwa
kinachoendelea chini ya Hood?

570
00:22:52,974 --> 00:22:55,890
Naam, juu ya mkono wa kushoto upande ni kamba,
ambayo ni baadhi ya aina ya kutofautiana,

571
00:22:55,890 --> 00:22:56,785
na ni kuitwa s.

572
00:22:56,785 --> 00:23:00,019
Hivyo Mimi najua kuwa hii ni kwa kutumia kumbukumbu,
au RAM, katika kompyuta yangu kwa namna fulani.

573
00:23:00,019 --> 00:23:02,060
Hivyo nina kwenda kwa abstractly
kuteka kwamba kama mraba.

574
00:23:02,060 --> 00:23:04,820
32 bits, ni zamu nje, lakini
zaidi juu ya kwamba katika siku zijazo.

575
00:23:04,820 --> 00:23:06,410
Na kisha, nini kinaendelea juu ya hapa?

576
00:23:06,410 --> 00:23:08,700
>> Naam, GetString ni wazi
anapata kamba kutoka kwa mtumiaji.

577
00:23:08,700 --> 00:23:11,360
Na GetString got
Zamyla au Gabe au Daven.

578
00:23:11,360 --> 00:23:14,640
Basi hebu kuchagua kwanza
kati ya hizo, ambayo ilikuwa Daven.

579
00:23:14,640 --> 00:23:19,174
Hivyo kwa ufanisi, nini GetString got
mimi katika kesi hiyo ya kwanza ilikuwa D-v-e-n.

580
00:23:19,174 --> 00:23:22,690

581
00:23:22,690 --> 00:23:25,045
Na kisha, nini mwingine alifanya
ni nipe siri?

582
00:23:25,045 --> 00:23:25,920
Watazamaji: [inaudible]

583
00:23:25,920 --> 00:23:28,720
DAVID J. Malan: Yeah,
/ 0 au null tabia.

584
00:23:28,720 --> 00:23:30,550
Hivyo ni ufanisi alinipa kamba.

585
00:23:30,550 --> 00:23:34,550
Lakini sisi tayari kujua kutoka uliopita
inaonekana kwamba string ni tu safu

586
00:23:34,550 --> 00:23:37,895
ya wahusika, na ni terminated na
hii sentinel tabia maalum, / 0.

587
00:23:37,895 --> 00:23:39,220

588
00:23:39,220 --> 00:23:42,310
>> Lakini kama hii ni kweli
na hii ni mraba,

589
00:23:42,310 --> 00:23:44,160
hii ni wazi Mstatili kubwa sana.

590
00:23:44,160 --> 00:23:46,830
Na hakika, hii ni,
Mimi kudai, bits 32 tu.

591
00:23:46,830 --> 00:23:49,500
Na hii ni wazi zaidi ya 32
bits, kwa sababu hii pengine ni

592
00:23:49,500 --> 00:23:51,583
nane pamoja na nane pamoja na nane
pamoja na nane pamoja na nane,

593
00:23:51,583 --> 00:23:53,320
kwa sababu tu ya ka katika ASCII.

594
00:23:53,320 --> 00:23:57,030
Jinsi heck ni sisi kwenda na kifafa
Daven katika hili sanduku kidogo hapa?

595
00:23:57,030 --> 00:23:59,880
>> Naam, ni nini GetString kweli kufanya?

596
00:23:59,880 --> 00:24:03,680
Naam, gridi ya taifa hii hapa inawakilisha
kumbukumbu ya kompyuta yangu au RAM.

597
00:24:03,680 --> 00:24:07,564
Basi hebu kiholela kusema kwamba kama
kila moja ya haya inawakilisha Byte,

598
00:24:07,564 --> 00:24:09,730
basi tunaweza kufikiri ya kila
Byte kama kuwa mitaani,

599
00:24:09,730 --> 00:24:13,830
kama 33 Oxford Street, au 34
Oxford Street, au 35 Oxford Street.

600
00:24:13,830 --> 00:24:16,700
>> Hivyo tu kama nyumba na anwani
na majengo na anwani,

601
00:24:16,700 --> 00:24:19,810
hivyo kufanya ka ya mtu binafsi ya
kumbukumbu na anwani au namba

602
00:24:19,810 --> 00:24:21,042
kwamba kipekee kutambua yao.

603
00:24:21,042 --> 00:24:22,000
Sasa, hii ni holela.

604
00:24:22,000 --> 00:24:25,370
Lakini kushika ni rahisi, mimi nina kwenda kwa
kutumia hexadecimal tu kwa mkataba huo,

605
00:24:25,370 --> 00:24:28,200
lakini 0x ina maana chochote
kuliko "hii ni hexadecimal."

606
00:24:28,200 --> 00:24:31,030
na mimi nina kwenda kudai kwamba
"D" mwisho hadi saa Byte One katika kumbukumbu.

607
00:24:31,030 --> 00:24:34,210
>> I got kitu kingine kinachoendelea katika
kumbukumbu, hivyo Daven got doa kwanza

608
00:24:34,210 --> 00:24:35,509
katika Byte One.

609
00:24:35,509 --> 00:24:36,800
Hii basi, ni kwenda kuwa 0x2.

610
00:24:36,800 --> 00:24:37,831

611
00:24:37,831 --> 00:24:38,705
Hii ni kwenda 0x3.

612
00:24:38,705 --> 00:24:39,840

613
00:24:39,840 --> 00:24:41,800
Hii ni kwenda kuwa 0x4.

614
00:24:41,800 --> 00:24:43,025
Hii ni kwenda 0x5.

615
00:24:43,025 --> 00:24:44,025
Hii ni kwenda kuwa 0x6.

616
00:24:44,025 --> 00:24:45,560

617
00:24:45,560 --> 00:24:48,290
>> Lakini mara moja kuanza kufikiri
kuhusu nini matendo ya kompyuta

618
00:24:48,290 --> 00:24:50,710
chini ya Hood,
unaweza kuanza kudai

619
00:24:50,710 --> 00:24:54,960
jinsi gani, baadhi ya miaka iliyopita, ingekuwa
kutekelezwa C yenyewe.

620
00:24:54,960 --> 00:24:58,360
GetString pengine ni nini
returning-- kwa sababu

621
00:24:58,360 --> 00:25:00,946
anahisi kama si
kurudi Daven, per se,

622
00:25:00,946 --> 00:25:03,320
kwa sababu yeye hakika si kwenda
fit katika hii box-- kidogo

623
00:25:03,320 --> 00:25:05,090
hivyo kile ni GetString pengine kurudi?

624
00:25:05,090 --> 00:25:07,958

625
00:25:07,958 --> 00:25:08,920
>> Watazamaji: [inaudible]

626
00:25:08,920 --> 00:25:10,540
>> DAVID J. Malan: eneo la Daven.

627
00:25:10,540 --> 00:25:12,770
Na imekuwa ni kufanya hivyo
tangu wiki moja.

628
00:25:12,770 --> 00:25:16,150
Nini GetString ni kweli
kurudi ni si kamba, per se.

629
00:25:16,150 --> 00:25:17,780
Hiyo ni moja ya nyeupe kidogo uongo.

630
00:25:17,780 --> 00:25:22,520
Ni kurudi pepe ya
kamba katika kumbukumbu, anwani ya kipekee.

631
00:25:22,520 --> 00:25:24,820
Daven anaishi saa 33 Oxford Street.

632
00:25:24,820 --> 00:25:29,310
Lakini zaidi kwa ufupi, Gavin anaishi
katika 0x1, anwani Idadi Mmoja.

633
00:25:29,310 --> 00:25:32,280
>> Basi nini anapata kuweka katika hii
sanduku kidogo basi, kuwa wazi,

634
00:25:32,280 --> 00:25:35,930
ni tu pepe ya kamba hiyo.

635
00:25:35,930 --> 00:25:38,110
Hivyo muda wote huu, hii
ina kinachoendelea.

636
00:25:38,110 --> 00:25:41,650
Lakini nini hii mwanga katika
sasa ni kwamba kama kila s ina

637
00:25:41,650 --> 00:25:44,710
Idadi ya ndani yake, ambaye ni
kuacha wewe, programu,

638
00:25:44,710 --> 00:25:47,970
kutoka kuweka idadi yoyote katika
yoyote kutofautiana na kuruka tu

639
00:25:47,970 --> 00:25:49,080
kwa kuwa chunk ya kumbukumbu?

640
00:25:49,080 --> 00:25:51,320
Na hakika, tutaweza kuona
hiyo ni tishio wakati ujao.

641
00:25:51,320 --> 00:25:53,500
>> Lakini kwa sasa, hii anahisi halitoshi.

642
00:25:53,500 --> 00:25:55,630
Kama mimi kusema, kupata yangu
kamba, wewe nipe Daven.

643
00:25:55,630 --> 00:25:57,230
Lakini wewe si kweli nipe Daven.

644
00:25:57,230 --> 00:25:59,310
Wote nipe ni Daven ya mahali.

645
00:25:59,310 --> 00:26:04,310
Je, mimi kisha kujua kwa uhakika
ambapo Daven huanza na ends--

646
00:26:04,310 --> 00:26:07,140
hadithi ya kupata weird--
ambapo Daven huanza na kuishia,

647
00:26:07,140 --> 00:26:10,435
na kisha, karibu
kamba katika kumbukumbu kuanza?

648
00:26:10,435 --> 00:26:11,520

649
00:26:11,520 --> 00:26:13,620
>> Naam, kama wewe ni kuwapatia
me mwanzo wa Daven,

650
00:26:13,620 --> 00:26:17,230
kimsingi, jinsi gani mimi kujua
ambapo mwisho wa jina lake ni?

651
00:26:17,230 --> 00:26:20,550
Hiyo maalum null tabia, ambayo
ni muhimu zaidi sasa

652
00:26:20,550 --> 00:26:23,040
kama masharti chini ya
kofia ni tu kutambuliwa

653
00:26:23,040 --> 00:26:25,820
kipekee na makazi yao katika kumbukumbu.

654
00:26:25,820 --> 00:26:28,130
Hivyo muda wote huu, hiyo ni
nini imekuwa kinachoendelea.

655
00:26:28,130 --> 00:26:32,470
>> Hivyo wakati sisi kuangalia sasa katika
code hapa, kueleza

656
00:26:32,470 --> 00:26:35,790
kama wewe ungekuwa mdudu katika line 26.

657
00:26:35,790 --> 00:26:39,560
Kwa nini ni Zamyla na Zamyla tofauti?

658
00:26:39,560 --> 00:26:41,330
Kwa nini ni Gabe na Gabe tofauti?

659
00:26:41,330 --> 00:26:42,154
Yeah, katika nyuma.

660
00:26:42,154 --> 00:26:43,390
>> Watazamaji: Wana anwani tofauti.

661
00:26:43,390 --> 00:26:45,931
>> DAVID J. Malan: Tu kwa sababu
wana anwani tofauti.

662
00:26:45,931 --> 00:26:48,820
Kwa sababu wakati wewe piga GetString
tena, ambayo mimi itabidi kufanya haraka hapa,

663
00:26:48,820 --> 00:26:52,870
kama hii ni mstari wa pili, kamba
t, kama mimi katika mpango huo,

664
00:26:52,870 --> 00:26:55,030
sawa na mwingine wito kwa GetString.

665
00:26:55,030 --> 00:26:56,370

666
00:26:56,370 --> 00:26:58,670
wakati mwingine mimi wito
GetString, mimi nina kwenda

667
00:26:58,670 --> 00:27:00,190
kupata chunk tofauti ya kumbukumbu.

668
00:27:00,190 --> 00:27:02,220
>> GetString ni kuruhusiwa
kuuliza uendeshaji

669
00:27:02,220 --> 00:27:03,800
mfumo kwa ajili ya kumbukumbu zaidi na zaidi.

670
00:27:03,800 --> 00:27:07,894
Ni si kwenda kutumia tena huo
ka sita kila wakati.

671
00:27:07,894 --> 00:27:09,810
Ni kwenda kupata mpya
chunk ya kumbukumbu, ambayo

672
00:27:09,810 --> 00:27:12,780
ina maana t ni kwenda kupata
baadhi thamani mengine zaidi ya hapa.

673
00:27:12,780 --> 00:27:15,380
>> Hivyo wakati mimi kufanya s ni sawa na =
t, wewe si kulinganisha

674
00:27:15,380 --> 00:27:17,880
D dhidi ya huu na dhidi ya
huu na V dhidi ya hii.

675
00:27:17,880 --> 00:27:19,588
Wewe ni kulinganisha hii
dhidi ya hii, ambayo

676
00:27:19,588 --> 00:27:24,020
kusema ukweli ni pretty useful-- useless--
ni pretty haina maana, kwa sababu ambao kwa kweli

677
00:27:24,020 --> 00:27:25,830
anayejali ambapo masharti ni katika kumbukumbu?

678
00:27:25,830 --> 00:27:26,850
>> Na hakika, sisi si.

679
00:27:26,850 --> 00:27:28,980
Na sisi siyo kwenda
kuanza hasa kujali.

680
00:27:28,980 --> 00:27:34,180
Tu kwa kiasi kwamba mende yanaweza kutokea
na vitisho vya usalama yanaweza kutokea mapenzi

681
00:27:34,180 --> 00:27:36,100
sisi kweli kuanza huduma kuhusu hili.

682
00:27:36,100 --> 00:27:37,230
Basi hebu kurekebisha tatizo hili.

683
00:27:37,230 --> 00:27:39,650
Zamu nje, wewe kurekebisha super tu.

684
00:27:39,650 --> 00:27:42,600
>> Na hebu kweli, kabla ya mimi
yanaonyesha kwamba tena, gani

685
00:27:42,600 --> 00:27:47,170
nini kama katika CS50 darasani,
na wewe alikuwa na kutekeleza

686
00:27:47,170 --> 00:27:48,600
kulinganisha dhidi ya masharti mawili.

687
00:27:48,600 --> 00:27:51,440
You wazi hawezi tu kutumia s ni sawa na = t.

688
00:27:51,440 --> 00:27:54,090
Lakini tu mantiki, jinsi
ingekuwa wewe kulinganisha kamba hii

689
00:27:54,090 --> 00:27:56,370
dhidi ya kamba hii kwa kutumia C kanuni?

690
00:27:56,370 --> 00:27:56,880
Yeah.

691
00:27:56,880 --> 00:27:58,780
>> Watazamaji: Tu kufanya
kwa kitanzi [inaudible]

692
00:27:58,780 --> 00:28:00,670

693
00:28:00,670 --> 00:28:01,670
DAVID J. Malan: Perfect.

694
00:28:01,670 --> 00:28:02,900
Watazamaji: [inaudible]

695
00:28:02,900 --> 00:28:03,310
DAVID J. Malan: Yeah.

696
00:28:03,310 --> 00:28:05,390
Tu ya matumizi ya kwa kitanzi au a
kitanzi wakati au chochote.

697
00:28:05,390 --> 00:28:08,710
Lakini tu kuomba wazo msingi kwamba kama
hii ni chunk ya kumbukumbu au safu

698
00:28:08,710 --> 00:28:11,590
na hii ni, iterate juu ya
wote wawili kwa wakati mmoja.

699
00:28:11,590 --> 00:28:12,960
Na tu kulinganisha barua.

700
00:28:12,960 --> 00:28:14,260
>> Na nimepata kuwa
kidogo makini, kwa sababu wewe

701
00:28:14,260 --> 00:28:16,247
hawataki kidole moja
kwenda nyuma ya nyingine

702
00:28:16,247 --> 00:28:18,080
kwa sababu kamba moja ni
muda mrefu zaidi ya wengine.

703
00:28:18,080 --> 00:28:21,380
Hivyo wewe ni kwenda unataka kuangalia kwa
hii thamani maalum mwishoni, null.

704
00:28:21,380 --> 00:28:24,017
Lakini kwa kweli ni, katika
mwisho, kama rahisi kama hiyo.

705
00:28:24,017 --> 00:28:26,100
Na kusema ukweli, hatuna haja ya
reinvent gurudumu hiyo.

706
00:28:26,100 --> 00:28:27,960
Hapa ni Version Barua.

707
00:28:27,960 --> 00:28:32,910
Na kile Mimi nina kwenda kusema hapa ni kwamba
badala ya kulinganisha s ni sawa na = t,

708
00:28:32,910 --> 00:28:38,964
Mimi nina badala kwenda kusema, kama kamba
kulinganisha s comma t sawa na = 0.

709
00:28:38,964 --> 00:28:40,130
Sasa, ni nini string kulinganisha?

710
00:28:40,130 --> 00:28:43,046
>> Ni zinageuka, ni kazi ambayo
kuja na C, ambao lengo katika maisha

711
00:28:43,046 --> 00:28:44,650
ni kulinganisha masharti mawili.

712
00:28:44,650 --> 00:28:48,300
Na koroga kulinganisha, kama sisi kusoma wake
mtu au nyaraka ukurasa au CS50

713
00:28:48,300 --> 00:28:50,630
kumbukumbu, itakuwa
tu kukuambia kwamba koroga

714
00:28:50,630 --> 00:28:55,730
kulinganisha anarudi ama hasi
idadi au idadi chanya au sifuri,

715
00:28:55,730 --> 00:28:57,660
ambapo zero maana wao ni sawa.

716
00:28:57,660 --> 00:28:58,570
>> Hivyo tu dhana tu.

717
00:28:58,570 --> 00:29:00,390
Nini kinaweza maana kama
kuchochea anarudi kulinganisha

718
00:29:00,390 --> 00:29:02,110
thamani hasi au chanya thamani?

719
00:29:02,110 --> 00:29:02,785

720
00:29:02,785 --> 00:29:04,285
Watazamaji: Kubwa kuliko au chini ya.

721
00:29:04,285 --> 00:29:05,570
DAVID J. Malan: Yeah,
kubwa zaidi kuliko au chini ya.

722
00:29:05,570 --> 00:29:08,640
Hivyo kama wewe alitaka kutatua nzima
rundo ya masharti katika dictionary--

723
00:29:08,640 --> 00:29:12,975
kama sisi hatimaye chini road--
kazi kamili kwa kutumia uwezekano,

724
00:29:12,975 --> 00:29:15,850
kwa sababu ni kwenda kufanya hivyo
kulinganisha ya masharti kwa ajili yenu, na kuwaambia

725
00:29:15,850 --> 00:29:20,060
wewe gani huja kabla ya b, au gani
b kuja kabla ya alphabetically.

726
00:29:20,060 --> 00:29:21,490
Tunaweza kufanya hasa kwamba.

727
00:29:21,490 --> 00:29:23,620
>> Na ilani mimi mtu mwingine
kitu katika mfano huu.

728
00:29:23,620 --> 00:29:26,870
Nini kingine imebadilika juu
up katika kazi hii kuu?

729
00:29:26,870 --> 00:29:28,500

730
00:29:28,500 --> 00:29:29,350
Char *.

731
00:29:29,350 --> 00:29:31,150
Na hii ni kwamba nyingine nyeupe uongo.

732
00:29:31,150 --> 00:29:33,750
Muda wote huu, wakati wewe wameweza
wamekuwa kuandika kamba,

733
00:29:33,750 --> 00:29:38,350
tumekuwa siri rewriting
kamba kama * Char ili Clang kweli

734
00:29:38,350 --> 00:29:39,270
anaelewa wewe.

735
00:29:39,270 --> 00:29:42,450
>> Kwa maneno mengine, katika CS50.h
na kama tutaweza hatimaye kuona,

736
00:29:42,450 --> 00:29:45,950
sisi alifanya kamba kisawe kuitwa
hiyo ni kitu kimoja kama * Char.

737
00:29:45,950 --> 00:29:49,910
Na kwa sasa, kujua tu kwamba
*, Katika hali hii, angalau,

738
00:29:49,910 --> 00:29:51,286
ina maana mahali.

739
00:29:51,286 --> 00:29:52,210
>> anwani ya nini?

740
00:29:52,210 --> 00:29:56,390
Naam, ukweli kwamba mimi alisema
* Char, na si int au kuelea * *,

741
00:29:56,390 --> 00:30:00,820
ina maana kwamba * Char ni
pepe ya char.

742
00:30:00,820 --> 00:30:06,770
Hivyo hii sanduku kidogo hapa, aka
kamba, ni kweli ya aina * Char,

743
00:30:06,770 --> 00:30:10,490
ambayo ni tu njia dhana ya kusema,
katika sanduku hii kwenda ya mahali.

744
00:30:10,490 --> 00:30:12,430
Na je anwani kwamba rejea?

745
00:30:12,430 --> 00:30:13,780
Inavyoonekana, char.

746
00:30:13,780 --> 00:30:16,410
>> Lakini tunaweza kabisa
na int * na mambo mengine.

747
00:30:16,410 --> 00:30:20,790
Lakini kwa sasa, * Char ni kweli zaidi
moja kwa moja na moja ya riba.

748
00:30:20,790 --> 00:30:23,310
Hivyo tatizo hili ni kwenda
kupanda, ingawa, tena.

749
00:30:23,310 --> 00:30:24,830
>> Tuseme mimi kufungua mpango huu.

750
00:30:24,830 --> 00:30:27,670
Hebu angalia kama sasa tunaweza kutabiri
nini mbaya na kanuni hii.

751
00:30:27,670 --> 00:30:31,140
Hivyo katika mpango huu, nakala-0, mimi nina
kwenda mbele na tena kuwaita

752
00:30:31,140 --> 00:30:34,190
GetString na kuhifadhi thamani katika s.

753
00:30:34,190 --> 00:30:38,800
>> Na kisha, kwa nini mimi kufanya hili,
tu kama mawaidha kutoka wiki iliyopita?

754
00:30:38,800 --> 00:30:40,960
Sisi alifanya kusema kwamba GetString
wakati mwingine anarudi null.

755
00:30:40,960 --> 00:30:42,793
Ina maana gani kama
GetString anarudi null?

756
00:30:42,793 --> 00:30:45,040

757
00:30:45,040 --> 00:30:46,034
Kitu potoka.

758
00:30:46,034 --> 00:30:48,950
Ni pengine ina maana string ni pia
kubwa, nje ya kompyuta ya kumbukumbu.

759
00:30:48,950 --> 00:30:51,724
Ni hutokea super, super, super
mara chache, lakini inaweza kutokea.

760
00:30:51,724 --> 00:30:53,890
Tunataka kuangalia kwa ajili yake,
na kwamba wote sisi ni kufanya.

761
00:30:53,890 --> 00:30:57,910
>> Kwa sababu tutaweza kuona sasa, kama huna
kuanza kuangalia huongeza kwa ajili ya mambo

762
00:30:57,910 --> 00:31:00,870
kama null, waweza
kweli kuanza kwenda

763
00:31:00,870 --> 00:31:03,106
kwa anwani katika kumbukumbu kwamba ni batili.

764
00:31:03,106 --> 00:31:05,980
Na wewe ni kwenda kuanza inducing
zaidi na zaidi segmentation makosa.

765
00:31:05,980 --> 00:31:08,360
Au katika Mac au PC, tu
kusababisha kompyuta hutegemea

766
00:31:08,360 --> 00:31:10,340
au mpango wa kufungia, uwezekano.

767
00:31:10,340 --> 00:31:14,930
>> Hivyo sasa, mimi kudai katika nakala-0.c, kwamba mimi
naenda nakala masharti hayo kwa njia

768
00:31:14,930 --> 00:31:15,685
ya mstari 28.

769
00:31:15,685 --> 00:31:16,850

770
00:31:16,850 --> 00:31:18,750
Na kisha, mimi nina kwenda
kudai chini

771
00:31:18,750 --> 00:31:21,430
hapa kwamba mimi nina kwenda
kubadili mmoja wao.

772
00:31:21,430 --> 00:31:22,330
>> Hivyo taarifa hii.

773
00:31:22,330 --> 00:31:24,370
Mimi nina wito rafiki yetu ya zamani strlen.

774
00:31:24,370 --> 00:31:28,960
Na tu kueleza katika lugha ya Kiingereza
nini mstari huu 34 ni kufanya?

775
00:31:28,960 --> 00:31:32,480
Je t bracket 0
kuwakilisha upande wa kushoto.

776
00:31:32,480 --> 00:31:32,980
Yeah.

777
00:31:32,980 --> 00:31:34,339
>> Watazamaji: tabia ya Kwanza ya t?

778
00:31:34,339 --> 00:31:35,880
DAVID J. Malan: tabia ya Kwanza ya t.

779
00:31:35,880 --> 00:31:36,379
Hiyo ni.

780
00:31:36,379 --> 00:31:40,024
Tabia ya kwanza ya t, nataka
hawawajui version uppercase

781
00:31:40,024 --> 00:31:41,190
ya tabia ya kwanza katika t.

782
00:31:41,190 --> 00:31:43,200
Hivyo hii ni pamoja na kuyafanyia
barua ya kwanza.

783
00:31:43,200 --> 00:31:46,340
Na kisha, jambo la mwisho sana mimi kufanya
katika mpango huu ni mimi kudai hapa

784
00:31:46,340 --> 00:31:50,340
awali, s, na hapa ni nakala, t.

785
00:31:50,340 --> 00:31:54,610
>> Lakini kulingana na hadithi sisi tu
aliiambia kuhusu nini kweli ni masharti,

786
00:31:54,610 --> 00:31:57,520
ni nini line 28 kweli
kufanya, na kile ni

787
00:31:57,520 --> 00:31:59,405
mdudu kusababisha kwenda
kuwa juu ya screen?

788
00:31:59,405 --> 00:32:01,300

789
00:32:01,300 --> 00:32:03,500
>> Hivyo kwanza, swali la kwanza, 28.

790
00:32:03,500 --> 00:32:09,040
Je, ni kamba t = s kweli kufanya?

791
00:32:09,040 --> 00:32:16,430
Kama tuna juu ya mkono wa kushoto
upande hapa kamba t = s;

792
00:32:16,430 --> 00:32:19,400
kwamba anatoa mimi sanduku moja
hapa na sanduku moja hapa.

793
00:32:19,400 --> 00:32:25,530
Na kudhani anwani hii ni 0x,
hebu sema, 50 wakati huu, kiholela.

794
00:32:25,530 --> 00:32:28,847
Je kamba t = s
kufanya chini ya Hood?

795
00:32:28,847 --> 00:32:30,340
>> Watazamaji: [inaudible]

796
00:32:30,340 --> 00:32:34,100
>> DAVID J. Malan: Ni maduka kumbukumbu
kushughulikia huko, ili 0x50 huenda huko.

797
00:32:34,100 --> 00:32:37,980
Hivyo kama sasa, mimi kwenda kwanza
tabia katika t na uppercase yake,

798
00:32:37,980 --> 00:32:39,535
nini mimi kufanya kwa ufanisi kwa s?

799
00:32:39,535 --> 00:32:41,300

800
00:32:41,300 --> 00:32:43,450
Mimi nina kweli kufanya kitu kimoja, sawa?

801
00:32:43,450 --> 00:32:47,680
Kwa sababu kama ya mitaani 0x50-- na ya haki, mimi
hawana chumba mengi juu ya bodi hapa,

802
00:32:47,680 --> 00:32:51,750
lakini kudhani kwamba hii ni 0x50 hapa chini,
mahali fulani katika kumbukumbu ya kompyuta yangu.

803
00:32:51,750 --> 00:32:55,825
>> Na mimi, kwa mfano, Gabe
Herufi za chini katika hapa, kama hii.

804
00:32:55,825 --> 00:32:57,120

805
00:32:57,120 --> 00:33:01,980
Nami nimesema t bracket
0 anapata mtaji.

806
00:33:01,980 --> 00:33:04,860
Naam, t bracket 0 ni
barua ya kwanza katika t.

807
00:33:04,860 --> 00:33:07,840
Hivyo g kidogo ni kwenda
kuwa kubwa G. Lakini tatizo

808
00:33:07,840 --> 00:33:09,410
ni, je, s pia uhakika na?

809
00:33:09,410 --> 00:33:10,300
>> Watazamaji: moja.

810
00:33:10,300 --> 00:33:11,841
>> DAVID J. Malan: kitu hicho hicho halisi.

811
00:33:11,841 --> 00:33:16,342
Hivyo maelezo rahisi labda,
hata kama syntax ni kidogo weird.

812
00:33:16,342 --> 00:33:17,050
Basi hebu kufanya hili.

813
00:33:17,050 --> 00:33:20,210
Tengeneza nakala-0 na kisha ./copy-0.

814
00:33:20,210 --> 00:33:21,820

815
00:33:21,820 --> 00:33:24,110
Sema kitu: Gabe.

816
00:33:24,110 --> 00:33:26,760
Na kwa bahati mbaya, wote wawili wa
yao sasa imekuwa mtaji,

817
00:33:26,760 --> 00:33:29,500
lakini kwa kuwa msingi
sababu kwamba sisi ni tu

818
00:33:29,500 --> 00:33:32,350
sasa kukabiliana na anwani.

819
00:33:32,350 --> 00:33:36,470
>> Hivyo ni jinsi gani sisi kuanza
address-- no pun intended--

820
00:33:36,470 --> 00:33:39,270
jinsi gani sisi kuanza kushughulikia
tatizo hili hasa?

821
00:33:39,270 --> 00:33:44,400
Naam, katika copy1.c, mambo yanakwenda
kupata kidogo ngumu zaidi.

822
00:33:44,400 --> 00:33:49,310
Lakini napenda kudai
conceptually rahisi ufumbuzi.

823
00:33:49,310 --> 00:33:50,852
>> Kwa bidii ili kupata katika mtazamo wa kwanza.

824
00:33:50,852 --> 00:33:53,560
Si kwenda kuwa rahisi kwa mara ya kwanza
wakati unapoandika nje, pengine,

825
00:33:53,560 --> 00:33:57,440
lakini kama tatizo ni kwamba
tu kufanya t = s tu

826
00:33:57,440 --> 00:33:59,694
nakala ya mitaani, nini,
tena kama naweza kuchukua juu ya wewe,

827
00:33:59,694 --> 00:34:02,110
ni kwenda kuwa suluhisho
kwa kweli kuiga kamba?

828
00:34:02,110 --> 00:34:04,906

829
00:34:04,906 --> 00:34:06,770
>> Watazamaji: Sisi itabidi pengine
kutumia kitanzi tena.

830
00:34:06,770 --> 00:34:06,890
>> DAVID J. Malan: Yeah.

831
00:34:06,890 --> 00:34:08,390
Hivyo sisi ni kwenda haja ya kitanzi tena.

832
00:34:08,390 --> 00:34:11,800
Na kwa sababu kama tunataka nakala
kamba s katika string mwingine,

833
00:34:11,800 --> 00:34:14,120
sisi pengine wanataka kufanya hivyo
tabia kwa tabia.

834
00:34:14,120 --> 00:34:17,199
Lakini tatizo ni, kama
hii ni awali s,

835
00:34:17,199 --> 00:34:22,159
sasa tunahitaji kuanza kupanga
kugawa kumbukumbu kwa ajili ya t.

836
00:34:22,159 --> 00:34:24,320
>> Kwa maneno mengine, hebu
redraw mara ya mwisho hii moja.

837
00:34:24,320 --> 00:34:28,659
Kama hii ni kamba s = GetString.

838
00:34:28,659 --> 00:34:30,956

839
00:34:30,956 --> 00:34:32,455
Na hebu kuweka hii up hapa, kama vile.

840
00:34:32,455 --> 00:34:36,639

841
00:34:36,639 --> 00:34:37,420
Hii ni GetString.

842
00:34:37,420 --> 00:34:39,070

843
00:34:39,070 --> 00:34:43,860
Na kisha, picha kwa ajili ya kitu
kama kwamba ni kwenda kuwa kama kabla,

844
00:34:43,860 --> 00:34:44,360
g-b-e- / 0.

845
00:34:44,360 --> 00:34:47,294

846
00:34:47,294 --> 00:34:48,960
Kwamba inaonekana kitu kidogo kama hii.

847
00:34:48,960 --> 00:34:53,650
Na s hiyo, sisi wito huu 0x50,
na kwamba kinaendelea kuwa 51, 52.

848
00:34:53,650 --> 00:34:54,409
>> Hivyo hii ni 0x50.

849
00:34:54,409 --> 00:34:55,679

850
00:34:55,679 --> 00:34:59,690
Na kisha, mimi kufanya string t.

851
00:34:59,690 --> 00:35:02,450
Katika kumbukumbu, hiyo ni kwenda tu kwa
nipe mraba kidogo kama hii.

852
00:35:02,450 --> 00:35:04,080
Basi nini hatua muhimu sasa?

853
00:35:04,080 --> 00:35:09,870
Kama mimi nataka nakala s katika t, nini
tupu gani sisi haja ya kujaza katika hapa?

854
00:35:09,870 --> 00:35:12,050
Au je, sisi haja ya
kufanya katika ngazi ya juu?

855
00:35:12,050 --> 00:35:14,101

856
00:35:14,101 --> 00:35:14,600
Yeah?

857
00:35:14,600 --> 00:35:16,200

858
00:35:16,200 --> 00:35:17,020
Mtu?

859
00:35:17,020 --> 00:35:17,690
Yeah.

860
00:35:17,690 --> 00:35:19,214
>> Watazamaji: Tunahitaji [inaudible].

861
00:35:19,214 --> 00:35:21,380
DAVID J. Malan: Yeah, sisi
haja ya kujaza tupu hii.

862
00:35:21,380 --> 00:35:24,340
Siwezi nakala na kisha
capitalize jina Gabe ya

863
00:35:24,340 --> 00:35:28,120
mpaka mimi kuuliza mfumo wa uendeshaji
kwa chunk nyingine ya kumbukumbu

864
00:35:28,120 --> 00:35:30,640
kwamba angalau kama kubwa kama awali.

865
00:35:30,640 --> 00:35:32,130
Hivyo kwamba zinatuacha na swali.

866
00:35:32,130 --> 00:35:36,080
>> Je, mimi kuuliza mfumo wa uendeshaji si
tu kwa ajili ya rahisi pointer-- kidogo

867
00:35:36,080 --> 00:35:38,530
kama hii inaitwa,
ya mitaani, pointer-- si

868
00:35:38,530 --> 00:35:40,980
kwa rahisi sanduku kidogo
kama hii inayoitwa kamba?

869
00:35:40,980 --> 00:35:44,200
Je, mimi kuuliza uendeshaji
mfumo kwa chunk kubwa ya kumbukumbu?

870
00:35:44,200 --> 00:35:48,430
Hivi sasa, nimekuwa tu waliopata kuwa nyuma
moja kwa moja kwa wito GetString.

871
00:35:48,430 --> 00:35:50,740
Hivyo ni jinsi ni GetString
hata kupata kumbukumbu yake?

872
00:35:50,740 --> 00:35:53,430
>> Naam, ni zamu nje kwamba kuna
kazi nyingine hii hapa

873
00:35:53,430 --> 00:35:55,160
kwamba tutaweza sasa kuanza kutumia.

874
00:35:55,160 --> 00:35:59,780
Sasa, hii inaonekana njia zaidi cryptic than--
na mimi ni mmoja tu ambaye anaweza kuona it--

875
00:35:59,780 --> 00:36:03,150
mstari huu inaonekana njia zaidi cryptic
kisha ni lazima katika mtazamo wa kwanza.

876
00:36:03,150 --> 00:36:04,650
Lakini hebu tease ni mbali.

877
00:36:04,650 --> 00:36:07,950
>> Kwa upande wa mkono wa kushoto, nina char * t.

878
00:36:07,950 --> 00:36:13,280
Hivyo katika Kiingereza, hebu kuanza kuunda
hukumu sahihi katika jargon ya kiufundi.

879
00:36:13,280 --> 00:36:19,757
Hivyo hii ni kugawa
variable ya aina * Char kuitwa t.

880
00:36:19,757 --> 00:36:21,090
Sasa, je, hiyo kweli maana?

881
00:36:21,090 --> 00:36:23,881
>> Naam, hiyo ina maana, je, Mimi naenda
kuweka katika variable hii inaitwa t?

882
00:36:23,881 --> 00:36:24,780

883
00:36:24,780 --> 00:36:26,402
pepe ya char.

884
00:36:26,402 --> 00:36:28,360
Hivyo hiyo ni rahisi,
zaidi ya kuridhisha njia

885
00:36:28,360 --> 00:36:29,930
ya kuelezea upande wa mkono wa kushoto.

886
00:36:29,930 --> 00:36:32,890
Hivyo kwamba inajenga sanduku hili hapa tu.

887
00:36:32,890 --> 00:36:34,760
Hivyo upande wa kulia,
labda, ni kwenda

888
00:36:34,760 --> 00:36:37,170
kutenga kuwa kubwa
chunk ya kumbukumbu jinsi gani?

889
00:36:37,170 --> 00:36:38,340
Basi hebu tease hii mbali.

890
00:36:38,340 --> 00:36:41,131
>> Ni balaa katika mtazamo wa kwanza,
lakini nini kinaendelea ndani ya hapa?

891
00:36:41,131 --> 00:36:43,740
Kwanza, kuna malloc, ambayo
ni inaonekana rafiki yetu mpya,

892
00:36:43,740 --> 00:36:45,450
"Kumbukumbu kutenga."

893
00:36:45,450 --> 00:36:49,560
Hivyo hii ni hoja kuwa alipita
ndani yake, hivyo ni hoja pretty kubwa.

894
00:36:49,560 --> 00:36:50,970
Basi hebu tease hii mbali.

895
00:36:50,970 --> 00:36:53,410
>> strlen ya s, bila shaka, inawakilisha the--

896
00:36:53,410 --> 00:36:54,142

897
00:36:54,142 --> 00:36:55,600
Watazamaji: idadi ya wahusika.

898
00:36:55,600 --> 00:36:56,710
DAVID J. Malan: Tu
idadi ya wahusika katika s.

899
00:36:56,710 --> 00:36:59,040
Hivyo urefu wa s, kamba ya awali.

900
00:36:59,040 --> 00:37:00,350
Hivyo G-b-e.

901
00:37:00,350 --> 00:37:02,320
Hivyo ni pengine nne katika kesi hii.

902
00:37:02,320 --> 00:37:05,485
Kwa nini mimi kufanya 1 baada ya
wito strlen ya s?

903
00:37:05,485 --> 00:37:06,360
Watazamaji: [inaudible]

904
00:37:06,360 --> 00:37:07,590
DAVID J. Malan: Kwa kuwa
maalum null tabia.

905
00:37:07,590 --> 00:37:11,260
Kama unaniuliza nini urefu wa
Jina Gabe ya, Mimi kwenda kusema minne.

906
00:37:11,260 --> 00:37:14,480
Chini ya Hood, ingawa, mimi haja
kwamba Byte tano for null tabia.

907
00:37:14,480 --> 00:37:16,100
Hivyo ndiyo sababu mimi nina kufanya 1.

908
00:37:16,100 --> 00:37:21,730
>> Sasa tu katika kesi wewe ni mbio hii
programu katika kompyuta nyingine kuliko, kusema,

909
00:37:21,730 --> 00:37:24,610
CS50 appliance,
ambapo ukubwa wa char

910
00:37:24,610 --> 00:37:26,350
inaweza kuwa tofauti
kutoka computer-- yangu mwenyewe

911
00:37:26,350 --> 00:37:30,590
zinageuka kuwa siwezi kuwaita hii
operator sizeof, tu kuuliza kompyuta,

912
00:37:30,590 --> 00:37:32,870
nini ni ukubwa wa
Char kwenye kompyuta hii?

913
00:37:32,870 --> 00:37:37,400
>> Na kwa kuzidisha tano katika hii
mfano na ukubwa wa Char, ambayo

914
00:37:37,400 --> 00:37:40,440
juu ya kompyuta nyingi mapenzi
tu kuwa moja, malloc

915
00:37:40,440 --> 00:37:44,830
ni kwenda kutenga kwa ajili yangu hii kubwa
chunk ya kumbukumbu juu ya hapa juu ya haki.

916
00:37:44,830 --> 00:37:47,140
Na itakuja kwa return--
ni function-- hivyo ni

917
00:37:47,140 --> 00:37:48,265
kwenda na kurudi kwangu nini?

918
00:37:48,265 --> 00:37:50,914

919
00:37:50,914 --> 00:37:51,830
Watazamaji: anwani?

920
00:37:51,830 --> 00:37:53,709
DAVID J. Malan: anwani ya nini?

921
00:37:53,709 --> 00:37:55,250
Watazamaji: Bila kumbukumbu ni zilizotengwa?

922
00:37:55,250 --> 00:37:56,450
DAVID J. Malan: Bila
kumbukumbu ni zilizotengwa.

923
00:37:56,450 --> 00:37:59,189
Kwa hiyo mimi hawana wazo, kusema ukweli,
ambapo hii ni kwenda kuishia.

924
00:37:59,189 --> 00:38:01,480
Mimi nina kwenda kupendekeza kwamba
ni kwenda kuishia katika 0x88.

925
00:38:01,480 --> 00:38:02,770

926
00:38:02,770 --> 00:38:06,009
Kabisa holela, lakini
mahali fulani zaidi ya 0x50,

927
00:38:06,009 --> 00:38:08,800
kwa sababu mfumo wa uendeshaji, nini
Windows na Mac OS kufanya kwa ajili yangu, ni

928
00:38:08,800 --> 00:38:11,230
kuhakikisha kwamba ni kutoa
mimi chunks mbalimbali ya RAM.

929
00:38:11,230 --> 00:38:14,210
>> Hivyo hii ni thamani ambapo hii
chunk ya kumbukumbu inaweza kuishia.

930
00:38:14,210 --> 00:38:16,060
Hivyo hii ni nini mwisho juu katika hapa, 0x88.

931
00:38:16,060 --> 00:38:17,480

932
00:38:17,480 --> 00:38:21,570
Hivyo sasa wazi, siwezi kuelewa
kwamba hii si sawa na kama hii,

933
00:38:21,570 --> 00:38:23,960
kwa sababu wao ni akizungumzia katika
chunks mbalimbali ya kumbukumbu.

934
00:38:23,960 --> 00:38:29,980
Hivyo kama mimi sasa kweli wanataka nakala hii
katika, hebu kufanya ufumbuzi wako mapendekezo.

935
00:38:29,980 --> 00:38:36,870
>> Hebu tu kwenda, kujenga kwa kitanzi,
na kufanya t bracket i anapata s bracket i.

936
00:38:36,870 --> 00:38:39,760
Kwa sababu sasa naweza kutumia
hii safu-kama nukuu,

937
00:38:39,760 --> 00:38:43,390
kwa sababu hata kama malloc sana
generically kutenga mimi kumbukumbu,

938
00:38:43,390 --> 00:38:45,290
kumbukumbu ni ka tu contiguous.

939
00:38:45,290 --> 00:38:47,240
Byte, Byte, Byte, nyuma kwa nyuma kwa nyuma.

940
00:38:47,240 --> 00:38:50,030
>> Naweza hakika kama programu
kutibu kama safu, ambayo

941
00:38:50,030 --> 00:38:55,090
ina maana naweza kutumia hii hatimaye ukoo
nukuu ya baadhi tu ya mabano mraba.

942
00:38:55,090 --> 00:38:56,462

943
00:38:56,462 --> 00:39:00,020
>> Hivyo basi mimi pause huko, kwa sababu
hii ni mengi wote kwa mara moja, hata

944
00:39:00,020 --> 00:39:03,530
ingawa wazo msingi kwa kurejea
ni kamba kwamba, muda wote huu,

945
00:39:03,530 --> 00:39:05,550
ni si data mpya aina per se.

946
00:39:05,550 --> 00:39:10,150
Ni tu kinachojulikana pointer,
anwani ya tabia,

947
00:39:10,150 --> 00:39:12,650
ambayo ina maana tu ni idadi
kwamba kwa mkataba wa binadamu

948
00:39:12,650 --> 00:39:15,350
sisi huwa na kuandika kama 0x kitu.

949
00:39:15,350 --> 00:39:18,590
>> Lakini ni tu ya simu,
kama 33 Oxford Street,

950
00:39:18,590 --> 00:39:20,530
ambayo hufanyika kuwa
CS jengo la mahali.

951
00:39:20,530 --> 00:39:22,000

952
00:39:22,000 --> 00:39:23,545
Maswali yoyote juu ya maelezo haya?

953
00:39:23,545 --> 00:39:24,790

954
00:39:24,790 --> 00:39:25,289
Yeah?

955
00:39:25,289 --> 00:39:28,530
>> Watazamaji: Kwa nini sisi kuangalia
kwa t sawa na null?

956
00:39:28,530 --> 00:39:30,740
>> DAVID J. Malan: Kwa nini sisi
kuangalia kwa t sawa na null?

957
00:39:30,740 --> 00:39:33,250
Kama sisi kusoma documentation--
question-- kubwa kwa malloc,

958
00:39:33,250 --> 00:39:37,020
ni kwenda kusema katika magazeti faini,
wakati mwingine malloc ili kurudi null,

959
00:39:37,020 --> 00:39:38,080
tu kama GetString.

960
00:39:38,080 --> 00:39:41,820
Na hakika, GetString anarudi null
kama, kwa upande wake, malloc anarudi null,

961
00:39:41,820 --> 00:39:43,130
kwa sababu GetString anatumia malloc.

962
00:39:43,130 --> 00:39:46,400
>> Na kwamba kinaweza kutokea ikiwa OS,
Mac OS, Windows, chochote, ni tu

963
00:39:46,400 --> 00:39:48,130
nje ya kumbukumbu kwa ajili yenu.

964
00:39:48,130 --> 00:39:49,820
Hivyo kwamba ni nini kilichotokea huko.

965
00:39:49,820 --> 00:39:52,910
>> Na napenda yatangaza jambo moja nyingine
kwamba ili tu pigo akili yako

966
00:39:52,910 --> 00:39:55,100
au kabisa kuwa mbali pia juu ya line.

967
00:39:55,100 --> 00:39:59,770
Lakini ngoja kuvuta up
sawa kwa kitanzi kwa kuiga,

968
00:39:59,770 --> 00:40:05,480
ambayo wakati iliyopita, kukumbuka mara
huu. t bracket i anapata s bracket i.

969
00:40:05,480 --> 00:40:06,740
>> Nice na user-kirafiki.

970
00:40:06,740 --> 00:40:09,330
Anahisi kama Wiki Barua tena.

971
00:40:09,330 --> 00:40:14,920
Lakini toleo hili kweli unaweza kuwa
kuandikwa upya kama hii, ambayo inaonekana cryptic.

972
00:40:14,920 --> 00:40:18,280
Ni mbinu ya kuitwa pointer
hesabu, anwani hesabu.

973
00:40:18,280 --> 00:40:19,600
Lakini kwa nini gani kazi hii?

974
00:40:19,600 --> 00:40:22,220
>> Sasa annoyingly,
waandishi wa C aliamua kutumia

975
00:40:22,220 --> 00:40:25,070
* Ishara kwa malengo tofauti.

976
00:40:25,070 --> 00:40:29,020
Tumeona ni kutumika mara moja tayari,
* Char, ambayo ina maana ya "nipe variable

977
00:40:29,020 --> 00:40:31,210
ambayo inaenda vyenye
pepe ya char. "

978
00:40:31,210 --> 00:40:33,990
Hivyo * Char katika mazingira
maana yake ni "nipe variable."

979
00:40:33,990 --> 00:40:40,050
>> Kwa bahati mbaya, kama wewe kutumia * bila
neno mbele yake, kama Char,

980
00:40:40,050 --> 00:40:41,905
ni sasa inaitwa
dereference operator.

981
00:40:41,905 --> 00:40:43,530
Na tutaweza kuona zaidi ya hii kabla ya muda mrefu.

982
00:40:43,530 --> 00:40:44,930
Lakini ni tu ina maana ya "kwenda huko."

983
00:40:44,930 --> 00:40:49,070
Ni kama kusema, kama mtu mitupu yangu
juu ya kipande cha karatasi "33 Oxford Street,"

984
00:40:49,070 --> 00:40:53,830
kama mimi kufanya "* 33 Oxford Street," hiyo ina maana
"Kwenda chini ya barabara ya jengo CS."

985
00:40:53,830 --> 00:40:57,220
>> Hivyo * tu ina maana kwenda huko kama
hakuna neno katika mbele yake.

986
00:40:57,220 --> 00:40:59,100
Kwa hiyo kile ni t, kuwa wazi?

987
00:40:59,100 --> 00:41:03,250
t ni pepe ya chunk ya
kumbukumbu ambayo ilitolewa nyuma yangu.

988
00:41:03,250 --> 00:41:06,650
s ni anwani ya nini, kuwa wazi,
katika mfano tumekuwa kujadili,

989
00:41:06,650 --> 00:41:07,500
ya lowercase Gabe?

990
00:41:07,500 --> 00:41:08,990

991
00:41:08,990 --> 00:41:10,005
s ni mahali of--

992
00:41:10,005 --> 00:41:11,585

993
00:41:11,585 --> 00:41:12,460
Watazamaji: kamba.

994
00:41:12,460 --> 00:41:14,126
DAVID J. Malan: Of Gabe ya jina ya awali.

995
00:41:14,126 --> 00:41:16,660
Hivyo ni pepe ya
chunk hii ya kumbukumbu.

996
00:41:16,660 --> 00:41:22,220
Hivyo kama mimi kusema t + i-- i, angalia,
ni tu rafiki yetu ya zamani.

997
00:41:22,220 --> 00:41:24,770
Ni tu index variable
hiyo iterating kutoka sifuri juu ya up

998
00:41:24,770 --> 00:41:26,960
kwa urefu wa kamba s.

999
00:41:26,960 --> 00:41:30,367
Hivyo ni kwenda kuwa sifuri, basi moja,
kisha mbili, kisha tatu, kisha nne.

1000
00:41:30,367 --> 00:41:33,200
Basi hebu kukusanyika hizi mpya
Puzzle vipande Scratch-kama, kama wewe,

1001
00:41:33,200 --> 00:41:36,140
hata ingawa, tena, syntax
ni mbali zaidi kuliko arcane Scratch.

1002
00:41:36,140 --> 00:41:39,522
Hivyo t ni anwani +
i ni kwenda nipe

1003
00:41:39,522 --> 00:41:42,480
idadi, kwa sababu haya yote ni
namba kwamba sisi tumekuwa kuchora kama hex.

1004
00:41:42,480 --> 00:41:43,560
Lakini wao ni idadi tu.

1005
00:41:43,560 --> 00:41:49,960
>> Hivyo kama pepe ya t sisi alisema
mara 0x88, nini 0x88 pamoja na sifuri.

1006
00:41:49,960 --> 00:41:51,564

1007
00:41:51,564 --> 00:41:53,980
Hata kama wewe ni si vizuri
na hex bado, kuchukua nadhani.

1008
00:41:53,980 --> 00:41:54,410
>> Watazamaji: ya awali.

1009
00:41:54,410 --> 00:41:55,850
>> DAVID J. Malan: Bado 0x88.

1010
00:41:55,850 --> 00:41:58,910
Kwa hiyo ni nini * 0x88 maana yake nini?

1011
00:41:58,910 --> 00:42:02,670
Ni maana yake, "kwenda huko" ambayo ina maana ya
kwa ufanisi, "kuweka kidole yako hapa."

1012
00:42:02,670 --> 00:42:06,930
Na sasa juu ya upande wa kulia wa
msemo huu, * na kisha katika parens,

1013
00:42:06,930 --> 00:42:11,586
s + i maana s, ambayo ni
kushughulikia hadi hapa ya g kidogo.

1014
00:42:11,586 --> 00:42:16,220
s + 0 ni, bila shaka, s, s chochote ni.

1015
00:42:16,220 --> 00:42:21,230
>> Hivyo sasa, ni * s, ambayo tu kama * 33
Oxford Street ina maana kwenda mahali

1016
00:42:21,230 --> 00:42:22,010
s.

1017
00:42:22,010 --> 00:42:24,170
Hivyo hapa ni kidole hii, mkono wa kulia.

1018
00:42:24,170 --> 00:42:26,050
Basi nini mimi kwenda nakala katika nini?

1019
00:42:26,050 --> 00:42:30,260
kitu juu ya haki, ambayo ni
Gabe, g kidogo hapa, katika hapa.

1020
00:42:30,260 --> 00:42:32,750
>> Na hivyo athari za kuwa
iteration kwanza ya kitanzi,

1021
00:42:32,750 --> 00:42:36,200
kama wewe mapendekezo, ingawa inaonekana
mambo ngumu zaidi kuliko kitu chochote

1022
00:42:36,200 --> 00:42:42,110
tumeona kabla, ni tu kusema
kwenda hapa na nakala ya kwamba tabia hapa.

1023
00:42:42,110 --> 00:42:44,700
Ni kutoa ramani kwa sehemu zote.

1024
00:42:44,700 --> 00:42:46,130
>> Na tutaweza kuona mbali zaidi ya hili.

1025
00:42:46,130 --> 00:42:50,600
Lakini kwa sasa, matumaini ni tu kwa
kuanzisha baadhi ya mawazo haya ya msingi.

1026
00:42:50,600 --> 00:42:53,550
Na hakika, hebu tuangalie
moja mpango wa mwisho hapa,

1027
00:42:53,550 --> 00:42:57,480
na kisha claymation ahadi,
ambayo itafanya kila kitu sawa.

1028
00:42:57,480 --> 00:42:57,980
Wote haki.

1029
00:42:57,980 --> 00:43:01,680
Hivyo basi mimi kufungua huko sisi kwenda up--.

1030
00:43:01,680 --> 00:43:02,850

1031
00:43:02,850 --> 00:43:05,440
Hivyo basi me-- tutaweza kurudi
kwa picha hii kabla ya muda mrefu.

1032
00:43:05,440 --> 00:43:08,360
Hebu kufungua mfano hii ya mwisho hapa.

1033
00:43:08,360 --> 00:43:09,440

1034
00:43:09,440 --> 00:43:12,710
>> Hivyo hapa ni super, super
mpango kwamba accomplishes

1035
00:43:12,710 --> 00:43:15,050
kitu katika maisha kwamba hana yafuatayo.

1036
00:43:15,050 --> 00:43:18,740
Ni kwanza anatangaza vigezo mbili, x
na y, ambayo si namba wakati huu,

1037
00:43:18,740 --> 00:43:19,240
per se.

1038
00:43:19,240 --> 00:43:20,448
Wao ni si integers, per se.

1039
00:43:20,448 --> 00:43:22,899
Wao ni inaonekana int *.

1040
00:43:22,899 --> 00:43:25,690
Hivyo tu mtu yeyote, ni nini maana
kama aina yako data, variable yako,

1041
00:43:25,690 --> 00:43:26,860
ni ya aina int * nyota?

1042
00:43:26,860 --> 00:43:30,240
Hiyo ni pepe ya int.

1043
00:43:30,240 --> 00:43:31,990
>> Hivyo nimekuwa na wazo ambapo ni bado.

1044
00:43:31,990 --> 00:43:35,150
Ni tu ina maana "kuweka, hatimaye,
pepe ya int hapa. "

1045
00:43:35,150 --> 00:43:38,340
0x50, 0x88, popote ni katika
kumbukumbu, pepe kwenda huko.

1046
00:43:38,340 --> 00:43:40,200
Na kwamba ni nini y ni
kwenda kuwa, kama vile.

1047
00:43:40,200 --> 00:43:44,920
>> Kama mimi sasa kusema x = malloc (sizeof (int)),
hii ni njia dhana ya kusema,

1048
00:43:44,920 --> 00:43:49,000
hey mfumo wa uendeshaji, kupitia malloc,
nipe kumbukumbu ya kutosha kwa ukubwa

1049
00:43:49,000 --> 00:43:52,370
ya int, ambayo pengine ni
kwenda kuwa bits 32 au ka nne.

1050
00:43:52,370 --> 00:43:53,680
>> Kwa hiyo ni nini malloc kurudi?

1051
00:43:53,680 --> 00:43:55,250
Malloc anarudi ya mahali.

1052
00:43:55,250 --> 00:43:57,020
Hivyo nini kinaendelea kupata kuhifadhiwa katika x?

1053
00:43:57,020 --> 00:44:00,600
anwani ya chunk ya
kumbukumbu, ka nne, kwamba malloc

1054
00:44:00,600 --> 00:44:03,360
tu kupatikana kwa ajili yangu kwa kuuliza
mfumo wa uendeshaji.

1055
00:44:03,360 --> 00:44:08,240
>> Sasa wakati huo huo, line
nne hapa, * x = 42.

1056
00:44:08,240 --> 00:44:09,990
Tu kuwa wazi,
nini kinaendelea chini huko?

1057
00:44:09,990 --> 00:44:11,530
Kwa upande wa mkono wa kushoto, * x.

1058
00:44:11,530 --> 00:44:13,610
hiyo ni kama * 33 Oxford Street.

1059
00:44:13,610 --> 00:44:15,523
Hivyo * x nini maana ya?

1060
00:44:15,523 --> 00:44:16,450
>> Watazamaji: Nenda.

1061
00:44:16,450 --> 00:44:17,908
>> DAVID J. Malan: Nenda kwa anwani hiyo.

1062
00:44:17,908 --> 00:44:20,466
Popote kwamba chunk ya
kumbukumbu ni, kwenda kwa hilo.

1063
00:44:20,466 --> 00:44:21,979
Na kuweka nini kuna, ni wazi?

1064
00:44:21,979 --> 00:44:22,520
Watazamaji: 42.

1065
00:44:22,520 --> 00:44:23,580
DAVID J. Malan: 42.

1066
00:44:23,580 --> 00:44:25,650
Haki wote, * y, wazo moja.

1067
00:44:25,650 --> 00:44:26,860
Kwenda mahali katika y.

1068
00:44:26,860 --> 00:44:31,740
Weka namba 13 huko,
lakini ni y wakati gani?

1069
00:44:31,740 --> 00:44:33,172

1070
00:44:33,172 --> 00:44:34,630
Watazamaji: Hakuna kumbukumbu kwa ajili ya y.

1071
00:44:34,630 --> 00:44:35,710
DAVID J. Malan: Kuna
hakuna kumbukumbu kwa ajili ya y.

1072
00:44:35,710 --> 00:44:38,215
Hivyo nini y pengine
zina, kama tumekuwa kusema?

1073
00:44:38,215 --> 00:44:38,520
>> Watazamaji: takataka.

1074
00:44:38,520 --> 00:44:39,480
>> DAVID J. Malan: Baadhi ya thamani ya takataka.

1075
00:44:39,480 --> 00:44:41,320
Sasa, thamani ya takataka ni bado idadi.

1076
00:44:41,320 --> 00:44:43,160
Ni bado unaweza kuwa na makosa kwa mahali.

1077
00:44:43,160 --> 00:44:45,160
Ni kana kwamba mtu
scribbled kitu chini,

1078
00:44:45,160 --> 00:44:48,002
na mimi vibaya kama maana
jengo baadhi chini ya mitaani.

1079
00:44:48,002 --> 00:44:50,460
Na kama wewe tu kujaribu kwenda katika
baadhi ya jengo huna mwenyewe,

1080
00:44:50,460 --> 00:44:53,710
au baadhi chunk ya kumbukumbu una si
imekuwa aliyopewa, mambo mabaya yanaweza kutokea.

1081
00:44:53,710 --> 00:44:57,740
Kompyuta inaweza ajali, au nyingine
tabia undetermined inaweza kutokea.

1082
00:44:57,740 --> 00:45:01,310
>> Hivyo intro, basi, kwa Binky ni hii.

1083
00:45:01,310 --> 00:45:04,290
Mimi bado kumbuka, 20
baadhi ya miaka isiyo ya kawaida baadaye,

1084
00:45:04,290 --> 00:45:07,200
ambapo mimi nilikuwa wakati mimi hatimaye
kueleweka kuyatumia.

1085
00:45:07,200 --> 00:45:09,520
>> Ambayo ni kusema, kama wewe
kuondoka hapa katika dakika ya tatu

1086
00:45:09,520 --> 00:45:12,170
na nadhani hawana
kuelewa kuyatumia, kutambua

1087
00:45:12,170 --> 00:45:14,410
Nami nimelikumbuka kwa ajili ya 20
miaka kwa sababu baadhi ya mambo

1088
00:45:14,410 --> 00:45:17,140
wakati na kwa nini ni hatimaye kuzamishwa
katika, kukaa na mafundisho yangu

1089
00:45:17,140 --> 00:45:19,501
wenzake, Nishat Mehta katika
nyuma ya Eliot Dining Hall.

1090
00:45:19,501 --> 00:45:21,250
Sasa, nimekuwa ikumbukwe
hii kwa sababu hii ilikuwa

1091
00:45:21,250 --> 00:45:23,920
moja ya mada I, katika
Hasa, Jihadi pamoja na.

1092
00:45:23,920 --> 00:45:26,470
Na kisha, hatimaye clicked,
kama Mimi kuthubutu kusema mengi ya mada

1093
00:45:26,470 --> 00:45:27,460
hatimaye mapenzi.

1094
00:45:27,460 --> 00:45:32,590
Na sasa, kwa kufanya kujisikia wote
furaha na wote zaidi kushawishi,

1095
00:45:32,590 --> 00:45:35,360
hebu tuangalie mwisho katika yetu
dakika ya mwisho tatu hapa katika Binky,

1096
00:45:35,360 --> 00:45:37,675
kutoka kwa rafiki yetu, Nick
Parlante kutoka Stanford.

1097
00:45:37,675 --> 00:45:38,910

1098
00:45:38,910 --> 00:45:41,580
>> [VIDEO avspelning]

1099
00:45:41,580 --> 00:45:42,750
>> -Hey, Binky.

1100
00:45:42,750 --> 00:45:43,500
Kuamka!

1101
00:45:43,500 --> 00:45:45,960
Ni wakati kwa pointer na furaha.

1102
00:45:45,960 --> 00:45:47,012
>> -Nini Hiyo?

1103
00:45:47,012 --> 00:45:48,723
Kujifunza kuhusu kuyatumia?

1104
00:45:48,723 --> 00:45:50,580
Oh, goody!

1105
00:45:50,580 --> 00:45:53,563
>> -Naam, Kwa kuanza, mimi nadhani sisi ni
kwenda haja kuyatumia wanandoa.

1106
00:45:53,563 --> 00:45:54,390
>> -OK.

1107
00:45:54,390 --> 00:45:57,930
Kanuni hii kutenga kuyatumia mbili,
ambayo inaweza kumweka kwa integers.

1108
00:45:57,930 --> 00:45:58,430
-OK.

1109
00:45:58,430 --> 00:46:02,140
Naam, naona kuyatumia mbili, lakini wao
hawaonekani kuwa akizungumzia chochote.

1110
00:46:02,140 --> 00:46:02,980
>> -Kwamba Ni haki.

1111
00:46:02,980 --> 00:46:05,100
Awali, kuyatumia
hawana uhakika na kitu chochote.

1112
00:46:05,100 --> 00:46:08,030
mambo wao kumweka kwa walioitwa
pointees, na kuweka yao juu ya

1113
00:46:08,030 --> 00:46:09,370
hatua tofauti.

1114
00:46:09,370 --> 00:46:10,220
>> -Oh, Haki, haki.

1115
00:46:10,220 --> 00:46:10,950
Nilijua kwamba.

1116
00:46:10,950 --> 00:46:12,385
pointees ni tofauti.

1117
00:46:12,385 --> 00:46:14,315
Eri, hivyo ni jinsi gani kutenga pointee?

1118
00:46:14,315 --> 00:46:15,340

1119
00:46:15,340 --> 00:46:15,960
>> -OK.

1120
00:46:15,960 --> 00:46:18,970
Naam, kanuni hii kutenga
mpya integer pointee,

1121
00:46:18,970 --> 00:46:20,950
na seti sehemu hii x kwa uhakika na hilo.

1122
00:46:20,950 --> 00:46:22,050

1123
00:46:22,050 --> 00:46:23,230
>> -Hey, Kwamba inaonekana bora.

1124
00:46:23,230 --> 00:46:25,060
Hivyo kufanya hivyo kufanya kitu fulani.

1125
00:46:25,060 --> 00:46:25,990
>> -OK.

1126
00:46:25,990 --> 00:46:30,455
Mimi itabidi dereference pointer x kwa
kuhifadhi namba 42 katika pointee yake.

1127
00:46:30,455 --> 00:46:32,830
Kwa hila hii, mimi itabidi haja yangu
Uchawi Wand ya Dereferencing.

1128
00:46:32,830 --> 00:46:34,130

1129
00:46:34,130 --> 00:46:36,080
>> -Wako Magic Wand ya Dereferencing?

1130
00:46:36,080 --> 00:46:37,357

1131
00:46:37,357 --> 00:46:38,190
That-- kwamba ni kubwa.

1132
00:46:38,190 --> 00:46:39,340

1133
00:46:39,340 --> 00:46:41,080
>> -Hii Ni nini code inaonekana kama.

1134
00:46:41,080 --> 00:46:44,110
Mimi itabidi kuanzisha idadi, na [POP]

1135
00:46:44,110 --> 00:46:44,700
>> -Hey, Kuangalia.

1136
00:46:44,700 --> 00:46:46,140
Kuna unaendelea.

1137
00:46:46,140 --> 00:46:50,980
>> -Basi Kufanya dereference juu ya x ifuatavyo
arrow kupata pointee yake.

1138
00:46:50,980 --> 00:46:53,160
Katika kesi hiyo, duka 42 huko.

1139
00:46:53,160 --> 00:46:57,710
Hey kujaribu kutumia kwa kuhifadhi idadi
13 kupitia pointer nyingine, y.

1140
00:46:57,710 --> 00:46:58,760
>> -OK.

1141
00:46:58,760 --> 00:47:03,270
Mimi itabidi kwenda juu hapa y,
na kupata namba 13 kuweka up.

1142
00:47:03,270 --> 00:47:07,930
Na kisha, kuchukua Wand ya
Dereferencing na tu [BUZZ]

1143
00:47:07,930 --> 00:47:08,960
>> -Oh!

1144
00:47:08,960 --> 00:47:09,500
>> -Oh, Hey!

1145
00:47:09,500 --> 00:47:11,090
Kwamba hakuwa na kazi.

1146
00:47:11,090 --> 00:47:15,630
Sema, Binky, sidhani dereferencing
y ni wazo nzuri, kwa sababu unajua,

1147
00:47:15,630 --> 00:47:17,850
kuanzisha pointee
ni hatua tofauti.

1148
00:47:17,850 --> 00:47:20,450
Na sidhani sisi milele alifanya hivyo.

1149
00:47:20,450 --> 00:47:21,480
>> -Good Uhakika.

1150
00:47:21,480 --> 00:47:21,980
-Yeah.

1151
00:47:21,980 --> 00:47:25,680
Sisi zilizotengwa pointer y, lakini sisi
kamwe kuweka kwa uhakika na pointee.

1152
00:47:25,680 --> 00:47:27,190

1153
00:47:27,190 --> 00:47:28,616
>> -Very Mwangalifu.

1154
00:47:28,616 --> 00:47:30,240
-Hey, Wewe ni kuangalia nzuri huko, Binky.

1155
00:47:30,240 --> 00:47:33,400
Je, unaweza kurekebisha hivyo kwamba pointi y
kwa pointee sawa kama x?

1156
00:47:33,400 --> 00:47:34,000
>> -Sure.

1157
00:47:34,000 --> 00:47:36,780
Mimi itabidi kutumia yangu uchawi Wand
Pointer ya Assignment.

1158
00:47:36,780 --> 00:47:38,740
>> -Je Kwamba kwenda kuwa
tatizo kama kabla?

1159
00:47:38,740 --> 00:47:39,240
-Hakuna.

1160
00:47:39,240 --> 00:47:40,660
Hii haina kugusa pointees.

1161
00:47:40,660 --> 00:47:44,450
Ni tu mabadiliko pointer moja kwa
uhakika na kitu kimoja kama mwingine.

1162
00:47:44,450 --> 00:47:45,450
>> -Oh, Naona.

1163
00:47:45,450 --> 00:47:48,200
Sasa y pointi kwenye sehemu moja kama x.

1164
00:47:48,200 --> 00:47:48,910
Hivyo kusubiri.

1165
00:47:48,910 --> 00:47:49,950
Sasa, y ni fasta.

1166
00:47:49,950 --> 00:47:51,120
Ina pointee.

1167
00:47:51,120 --> 00:47:54,510
Hivyo unaweza kujaribu Wand ya
Dereferencing tena kwa kutuma 13 juu.

1168
00:47:54,510 --> 00:47:56,510
>> -Uh, OK.

1169
00:47:56,510 --> 00:47:58,160
Hapa unaendelea. [POP]

1170
00:47:58,160 --> 00:47:59,340
>> -Hey, Kuangalia kwamba.

1171
00:47:59,340 --> 00:48:00,750
Sasa dereferencing kazi juu y.

1172
00:48:00,750 --> 00:48:04,991
Na kwa sababu kuyatumia wanashiriki
kwamba pointee moja, wao wote kuona 13.

1173
00:48:04,991 --> 00:48:05,490
-Yeah.

1174
00:48:05,490 --> 00:48:06,870
Kushiriki, chochote.

1175
00:48:06,870 --> 00:48:08,820
Hivyo ni sisi kwenda kubadili maeneo sasa?

1176
00:48:08,820 --> 00:48:09,440
>> Oh, kuangalia.

1177
00:48:09,440 --> 00:48:10,830
Sisi ni nje ya muda.

1178
00:48:10,830 --> 00:48:11,570
>> -But--

1179
00:48:11,570 --> 00:48:13,530
>> -Tu kumbuka tatu sheria pointer.

1180
00:48:13,530 --> 00:48:16,560
Idadi Mmoja, muundo wa msingi
ni kwamba una pointer,

1181
00:48:16,560 --> 00:48:18,680
na inaelekeza juu ya pointee.

1182
00:48:18,680 --> 00:48:20,640
Lakini pointer na
pointee ni tofauti,

1183
00:48:20,640 --> 00:48:22,610
na makosa ya kawaida
ni kuanzisha pointer,

1184
00:48:22,610 --> 00:48:25,000
lakini kusahau kuwapa pointee.

1185
00:48:25,000 --> 00:48:28,170
>> Idadi Barua, pointer dereferencing
kuanza saa pointer

1186
00:48:28,170 --> 00:48:31,050
na ifuatavyo mshale wake juu ya
kupata pointee yake.

1187
00:48:31,050 --> 00:48:33,400
Kama sisi wote kujua, hii
tu kazi kama kuna

1188
00:48:33,400 --> 00:48:36,270
pointee, ambayo aina ya
anapata nyuma ya namba moja ya utawala.

1189
00:48:36,270 --> 00:48:39,000
>> Idadi ya Tatu, pointer
zoezi inachukua pointer moja

1190
00:48:39,000 --> 00:48:42,320
na mabadiliko hayo kwa uhakika na
pointee sawa kama pointer mwingine.

1191
00:48:42,320 --> 00:48:44,160
Kwa hiyo baada ya kazi,
kuyatumia mbili

1192
00:48:44,160 --> 00:48:45,910
uhakika na pointee sawa.

1193
00:48:45,910 --> 00:48:47,990
Wakati mwingine, kwamba wito kugawana.

1194
00:48:47,990 --> 00:48:49,740
Na kwamba ni yote kuna hiyo, kwa kweli.

1195
00:48:49,740 --> 00:48:50,277
Bye-bye sasa.

1196
00:48:50,277 --> 00:48:51,110
[END video avspelning]

1197
00:48:51,110 --> 00:48:52,568
DAVID J. Malan: Hiyo ni kwa CS50.

1198
00:48:52,568 --> 00:48:55,110
Tutaona wewe wiki ijayo.

1199
00:48:55,110 --> 00:48:56,064