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>> SPIKA 1: Hebu tuangalie
katika maktaba CS50,

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00:00:01,860 --> 00:00:05,190
hasa GetInt kazi yake.

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00:00:05,190 --> 00:00:07,820
Hapa tuna chanzo halisi
kanuni kwa ajili ya GetInt.

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00:00:07,820 --> 00:00:12,050
Tena, ona kwamba si muda mrefu sana, na
zaidi ya hayo hufanya wakati kitanzi -

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00:00:12,050 --> 00:00:15,620
usio kitanzi wakati huo - kwamba tu
anarudi thamani mara moja tumekuwa kweli

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00:00:15,620 --> 00:00:17,400
kujipatia nini sisi ilivyotarajiwa.

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00:00:17,400 --> 00:00:18,700
Hebu kutembea kwa njia hiyo.

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>> Taarifa juu hapa kwanza,
kitanzi wakati huanza.

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00:00:21,650 --> 00:00:25,390
Taarifa ijayo kwamba tuna mstari wa kanuni
kwamba kweli wito GetString,

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na maduka ya thamani kurudi katika
variable, aitwaye line, kamba aina.

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00:00:29,620 --> 00:00:31,210
Sisi basi kufanya kidogo ya sanity kuangalia.

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00:00:31,210 --> 00:00:35,770
Kama line == null, kisha sisi ajabu
kurudi INT_MAX.

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00:00:35,770 --> 00:00:40,140
>> Sasa zinageuka kuwa INT_MAX ni
mara kwa mara maalum alitangaza mahali pengine

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kwamba unasema mkubwa iwezekanavyo
int kwamba unaweza kuwakilisha katika

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mpango kama hii.

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Sasa tumekuwa kiholela aliamua kurudi
INT_MAX kama mwangalizi thamani ya

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kila aina, moja kwamba tumekuwa zimehifadhiwa kama
maana hitilafu imetokea.

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Hivyo bei sisi kulipa, bila shaka, ni
kwamba GetInt unaweza inaonekana si

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kweli kurudi idadi kubwa kama
INT_MAX, kwa sababu hata kama inataka,

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kwamba thamani ya kurudi lazima kweli
kutafsiriwa na mpigaji -

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yeyote ni kwa kutumia GetInt -

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kama makosa ya aina fulani.

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>> Next, taarifa kwamba nimepata alitangaza
int n na char c.

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Katika line hii ya pili ya maadili ya, mimi wito
kazi kuitwa sscanf, kupita katika

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nne hoja.

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line, ambayo ni kamba mtumiaji
typed katika, "% i% c", ambayo ni format

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kamba kwamba mimi nina wanatarajia user nguvu
aina, ikifuatiwa na barua pepe ya

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n, na barua pepe ya c.

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00:01:30,920 --> 00:01:34,860
Sasa sscanf kusudi katika maisha ni kweli
Scan kamba kuangalia kwa

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format fulani kwamba programu
ina maalum kama hoja kuwa ya pili.

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00:01:38,700 --> 00:01:42,020
Katika kesi hiyo,% i ni katika
huko, kama ni% c.

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00:01:42,020 --> 00:01:46,700
Hivyo kama sscanf atakutana na int katika
pembejeo mtumiaji, kwamba int kuhifadhiwa

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ndani ya variable kuitwa n, kwa sababu
tuna zinazotolewa kama tatu

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00:01:50,270 --> 00:01:52,810
hoja ya sscanf ya barua pepe ya n.

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00:01:52,810 --> 00:01:56,870
Ambayo ina maana kwamba sscanf unaweza kweli kwenda
huko, na update thamani humo.

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>> Sasa, katika kesi aina ya mtumiaji
katika kitu zaidi

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ya tarakimu moja au zaidi -

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00:02:01,220 --> 00:02:03,570
kwa maneno mengine, char wa aina fulani -

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00:02:03,570 --> 00:02:07,940
kwamba pili variable c, ambaye anwani
sisi kupita katika sscanf kama nne wake

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00:02:07,940 --> 00:02:10,560
hoja pia kuwa watu wengi.

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00:02:10,560 --> 00:02:14,220
Sasa suala la mafanikio ya kuangalia kwa
tabia ya ziada kutoka kwa mtumiaji ni

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kwamba, kama yeye au yeye hana kushirikiana,
na aina katika zaidi ya int,

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00:02:17,360 --> 00:02:20,530
tutaweza kuwa na uwezo wa kuchunguza katika hii
namna, kwa sababu katika kesi hiyo, sscanf

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ni kwenda na kurudi 2, ikimaanisha kwamba
zote za placeholders walijawa

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na maadili.

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00:02:25,600 --> 00:02:30,360
Lakini sisi ni matumaini kwamba sscanf badala
anarudi 1, ambayo ina maana user tu

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zinazotolewa int.

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00:02:31,630 --> 00:02:34,480
>> Tufanye nini kama sscanf
kweli anarudi 1?

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00:02:34,480 --> 00:02:39,150
Naam, sisi mara moja bure line kwamba
user typed, na kisha sisi

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mara moja kurudi n, kuwa
kujipatia int.

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00:02:42,670 --> 00:02:47,180
Mwingine, kama sscanf haina kurudi 1, na
user hiyo hawakuwa kushirikiana,

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00:02:47,180 --> 00:02:51,470
sisi bado bure line, lakini sisi
sasa haraka mtumiaji tena.

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Na kwa sababu bado tuko ndani ya kwamba
vinginevyo usio kitanzi, mchakato

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00:02:55,390 --> 00:03:00,190
itaanza tena, na labda tena, na
labda tena, mpaka user kweli

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00:03:00,190 --> 00:03:01,500
hutoa sisi int.

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00:03:01,500 --> 00:03:21,490