1
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2
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ROB Bowden: Hi, jien Rob Bowden,
u ejja nitkellmu dwar quiz0.

3
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4
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>> Allura, ewwel domanda.

5
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Din hija l-kwistjoni fejn
inti meħtieġ għall-kodiċi l-għadd

6
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127 fil-basal binarja.

7
00:00:21,270 --> 00:00:23,550
Jekk int riedu, inti tista
jagħmlu l-konverżjoni regolari

8
00:00:23,550 --> 00:00:25,950
minn bi-- jew, minn deċimali għall-binarju.

9
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Iżda li probabbilment se
li tieħu ħafna ħin.

10
00:00:28,300 --> 00:00:31,750
I mean, inti tista 'figura li,
OK, 1 huwa fil hemm, 2 hija fil hemm,

11
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4 hija fil hemm, 8 ikun fil hemmhekk.

12
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Mod aktar faċli, 127 huwa 128 nieqes wieħed.

13
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Li bozza tad-dawl leftmost huwa l-128-bit.

14
00:00:42,013 --> 00:00:43,490

15
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Allura 127 huwa verament biss kollha
ta 'l-bozoz tad-dawl oħra,

16
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peress li hija l-leftmost
bozza tad-dawl minus 1.

17
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C'est għal din id-domanda.

18
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>> Mistoqsija waħda.

19
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Allura bi 3 bits inti tista
jirrappreżentaw 8 valuri distinti.

20
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Għaliex, allura, hija ta '7-akbar mhux negattiv li
integer deċimali inti tista 'tirrappreżenta?

21
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Ukoll, jekk nistgħu biss
jirrappreżentaw 8 valuri distinti,

22
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allura dak li aħna qed tmur biex tkun
li jirrappreżenta huwa 0 sa 7.

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0 jieħu wieħed mill-valuri.

24
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25
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>> Mistoqsija tnejn.

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Bil n bits, kemm distinta
Valuri tista tirrappreżenta?

27
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Allura, ma 'n bits, inti għandek 2
Valuri possibbli għal kull daqsxejn.

28
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Allura aħna għandna 2 Valuri possibbli għal
l-ewwel ftit, 2-valuri possibbli

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għat-tieni, it-2
possibbli għat-tielet.

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U sabiex għamilhom 2 darbiet 2 darbiet 2, u
finalment it-tweġiba hija 2 għall-n.

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>> Mistoqsija tlieta.

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X'hemm 0x50 fil binarja?

34
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Mela ftakar li hexadecimal għandha ħafna
konverżjoni sempliċi biex binarja.

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Allura hawnhekk, aħna biss bżonn tħares lejn
il-5 u t-0 indipendentement.

36
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Allura x'hemm 5 binarja?

37
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0101, dak l-1 bit u l-4 daqsxejn.

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X'hemm 0 binarja?

39
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Mhux delikata.

40
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0000.

41
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Hekk biss jpoġġuhom flimkien, u
dak l-għadd sħiħ binarju.

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01010000.

43
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U jekk int riedu inti tista
jieħdu off li leftmost żero.

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Huwa irrilevanti.

45
00:02:01,105 --> 00:02:02,920

46
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>> Mela allura alternattivament,
dak li huwa 0x50 fl deċimali?

47
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Jekk int riedu, inti could-- jekk int
aktar komda mal-binarju,

48
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inti tista 'tieħu din ir-risposta binarju
u jikkonvertu dan in deċimali.

49
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Jew nistgħu biss ftakar
li hexadeċimali.

50
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Allura li huwa 0 fil-post 0-th, u
5 huwa fil-16 sa l-ewwel post.

51
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Allura hawnhekk, aħna għandna 5 darbiet 16 għall-
ewwel, plus 0 ħinijiet 16 għall-żero,

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huwa 80.

53
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U jekk inti ħares lejn l-
titolu għall-mistoqsija,

54
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kien CS 80, li kien it-tip ta '
ħjiel li t-tweġiba għal din il-problema.

55
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>> Mistoqsija ħamsa.

57
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Għandna din l-iskrittura Scratch, li hija
tirrepeti 4 darbiet butir tal-karawett jelly.

58
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Allura kif do we issa kodiċi li fis-C?

59
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Well, aħna għandna here-- l-parti b'tipa grassa
hija l-unika parti li inti kellhom jimplimentaw.

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Allura aħna għandna 4 linja thats looping 4
ħinijiet,-printf Ing karawett jelly butir,

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mal-linja ġdida bħala l-problema titlob għal.

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63
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>> Sitt mistoqsija, problema oħra Scratch.

64
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Naraw li ninsabu fi dejjem loop.

65
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Aħna qed tgħid il-varjabbli i
u mbagħad inkrementazzjoni i mill-1.

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Issa rridu li tagħmel dan fil-C. Hemm
modi multipli nistgħu jkunu għamlu dan.

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Hawnhekk aħna ġara għall-kodiċi tal-
dejjem loop bħala filwaqt (veru).

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Allura aħna tiddikjara l-varjabbli i, biss
bħal kellna varjabbli i fil Scratch.

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Jiddikjara l-varjabbli i, u dejjem
filwaqt li (veru), nistgħu ngħidu l-varjabbli i.

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Allura printf% i-- jew inti tista ħadthom użati% d.

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Aħna ngħidu dak il-varjabbli, u
imbagħad inkrement huwa, i ++.

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>> Mistoqsija sebgħa.

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Issa rridu nagħmlu xi ħaġa simili ħafna
lil Mario dot c minn problema sett wieħed.

75
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Aħna rridu li tistampa dawn hashtags,
irridu li jistampaw ta 'ħames

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billi tlieta rettangolu ta 'dawn hashes.

77
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Allura kif huma aħna se tagħmel dan?

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Well, aħna nagħtuk kollu
mazz ta 'kodiċi, u inti biss

80
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għandek timla l-funzjoni grid istampar.

81
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>> Allura dak li ma PrintGrid look like?

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Well int passat l-
wisa 'u l-għoli.

83
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Allura għandna barra 4
loop, thats looping

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fuq kollha ta 'l-ringieli ta' dan
grid li aħna rridu li jistampaw.

85
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Imbagħad għandna l-inter-nested 4 loop,
li l-istampar fuq kull kolonna.

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Allura għal kull ringiela, aħna jistampaw għal
kull kolonna, hash wieħed.

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Imbagħad fl-aħħar tal-filliera aħna jistampaw
linja ġdida waħda biex tmur fil-filliera li jmiss.

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U li lilha għall-grid kollu.

89
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>> Mistoqsija tmienja.

91
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Funzjoni bħal PrintGrid huwa qal li
ikollhom effett sekondarju, iżda mhux ritorn

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valur.

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Jispjegaw id-distinzjoni.

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Allura dan jiddependi fuq inti ftakar
liema effett sekondarju hu.

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Ukoll, ritorn value--
nafu PrintGrid ma

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għandhom valur tar-ritorn, peress
dritt hawn jgħid null.

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Allura xi ħaġa li jirritorna null
ma verament ritorn xejn.

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Allura x'inhi l-effett sekondarju?

100
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Ukoll, effett sekondarju huwa
xejn li tip ta 'tippersisti

101
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wara l-truf tal-funzjoni
li ma kienx biss lura,

102
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u ma kienx biss mill-inputs.

103
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>> Allura, per eżempju, nistgħu
bidla varjabbli globali.

104
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Dan ikun effett sekondarju.

105
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F'dan il-każ partikolari,
effett sekondarju importanti ħafna

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huwa istampar għall-iskrin.

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Allura li hu effett sekondarju
li PrintGrid għandha.

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Aħna istampar dawn l-affarijiet għall-iskrin.

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U inti tista 'taħseb
li bħala effett sekondarju,

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peress li xi ħaġa li
tippersisti wara din il-funzjoni truf.

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Dik xi ħaġa barra mill-ambitu
ta 'din il-funzjoni li finalment

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qed tinbidel, il-
kontenut tal-iskrin.

113
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>> Mistoqsija disa.

115
00:05:05,839 --> 00:05:07,880
Ikkunsidra l-programm ta 'hawn taħt,
li linja numri

116
00:05:07,880 --> 00:05:09,740
ġew miżjuda għall
l-fini ta 'diskussjoni.

117
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Allura f'dan il-programm aħna biss
ssejjaħ GetString, maħżuna

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f'dan varjabbli i, u mbagħad
istampar dak il-varjabbli s.

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OK.

120
00:05:16,720 --> 00:05:19,090
Allura jispjegaw għaliex linja wieħed ikun preżenti.

121
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#include CS50 dot h.

122
00:05:20,920 --> 00:05:23,820
Għaliex għandna bżonn li #include CS50 dot h?

123
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Well aħna qed ssejjaħ l-
GetString funzjoni,

124
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u GetString huwa definit
fil-librerija CS50.

125
00:05:28,840 --> 00:05:31,600
Hekk jekk aħna ma kellhiex
#include CS50 dot h,

126
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aħna se tikseb dik id-dikjarazzjoni impliċitu
tal-iżball funzjoni GetString

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mill-kompilatur.

128
00:05:36,840 --> 00:05:40,110
Għalhekk għandna bżonn li jinkludi l-library--
għandna bżonn li jinkludi l-fajl tal-header,

129
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jew inkella l-kompilatur mhux se
jirrikonoxxu li GetString jeżisti.

130
00:05:42,870 --> 00:05:44,380

131
00:05:44,380 --> 00:05:46,140
>> Jispjegaw għaliex linja tnejn huwa preżenti.

132
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Allura standard IO dot h.

133
00:05:47,890 --> 00:05:50,430
Huwa eżattament l-istess
bħala l-problema ta 'qabel,

134
00:05:50,430 --> 00:05:53,310
ħlief minflok jittrattaw
GetString, aħna qed jitkellem dwar printf.

135
00:05:53,310 --> 00:05:56,654
Allura jekk aħna ma jgħidu li għandna bżonn
li jinkludi l-istandard IO dot h,

136
00:05:56,654 --> 00:05:58,820
allura aħna mhux se tkun kapaċi
li tuża l-funzjoni printf,

137
00:05:58,820 --> 00:06:00,653
minħabba li l-kompilatur
ma jkunux jafu dwar dan.

138
00:06:00,653 --> 00:06:01,750

139
00:06:01,750 --> 00:06:05,260
>> Why-- x'inhi l-importanza
ta null fil-linja erbgħa?

140
00:06:05,260 --> 00:06:08,010
Allura hawnhekk għandna int prinċipali (vojt).

141
00:06:08,010 --> 00:06:10,600
Li jinsab biss qal li aħna
ma jkollna ebda linja tal-kmand

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00:06:10,600 --> 00:06:12,280
argumenti prinċipali.

143
00:06:12,280 --> 00:06:17,390
Ftakar li nistgħu ngħidu int
parentesi ewlenin INT argc ARGV string.

144
00:06:17,390 --> 00:06:20,400
Allura hawnhekk għandna biss jgħidu nulli biex ngħidu aħna
qed ninjoraw argumenti linja tal-kmand.

145
00:06:20,400 --> 00:06:21,840

146
00:06:21,840 --> 00:06:25,225
>> Jispjegaw, fir-rigward tal-memorja, eżattament
dak GetString konformi sitt prospetti.

147
00:06:25,225 --> 00:06:27,040

148
00:06:27,040 --> 00:06:31,640
GetString huwa jirritorna blokk ta '
memorja, firxa ta 'karattri.

149
00:06:31,640 --> 00:06:34,870
Huwa tassew ma jirritornaw
pointer li l-ewwel karattru.

150
00:06:34,870 --> 00:06:37,170
Ftakar li string hija stilla char.

151
00:06:37,170 --> 00:06:41,360
Allura s huwa pointer għall-ewwel
karattru x'ikun l-sekwenza huwa

152
00:06:41,360 --> 00:06:43,510
li l-utent daħal fil-keyboard.

153
00:06:43,510 --> 00:06:47,070
U li l-memorja jiġri li jkun malloced,
hekk li l-memorja huwa fil-borġ.

154
00:06:47,070 --> 00:06:49,080

155
00:06:49,080 --> 00:06:50,450
>> Mistoqsija 13.

156
00:06:50,450 --> 00:06:51,960
Ikkunsidra l-programm hawn taħt.

157
00:06:51,960 --> 00:06:55,579
Allura dan kollu programm qed tagħmel
huwa printf-Ing 1 maqsum f'10.

158
00:06:55,579 --> 00:06:57,370
Allura meta miġbura u
esegwiti, dan il-programm

159
00:06:57,370 --> 00:07:01,170
outputs 0.0, anki jekk
1 maqsum f'10 hija 0.1.

160
00:07:01,170 --> 00:07:02,970
Allura għaliex hi 0.0?

161
00:07:02,970 --> 00:07:05,510
Ukoll, dan huwa minħabba
ta 'diviżjoni numru sħiħ.

162
00:07:05,510 --> 00:07:08,580
Allura 1 huwa integer, 10 huwa integer.

163
00:07:08,580 --> 00:07:11,980
Allura 1 maqsum f'10, kollox
hija trattata bħala interi,

164
00:07:11,980 --> 00:07:16,380
u fis-C, meta nagħmlu diviżjoni numru sħiħ,
aħna truncate kwalunkwe punt deċimali.

165
00:07:16,380 --> 00:07:19,590
Allura 1 maqsum f'10 hija
0, u allura aħna qed jippruvaw

166
00:07:19,590 --> 00:07:24,410
li jistampaw li bħala float, hekk
żero stampati bħala float huwa 0.0.

167
00:07:24,410 --> 00:07:27,400
U hu għalhekk li aħna nikseb 0.0.

168
00:07:27,400 --> 00:07:28,940
>> Ikkunsidra l-programm hawn taħt.

169
00:07:28,940 --> 00:07:31,280
Issa aħna qed istampar 0.1.

170
00:07:31,280 --> 00:07:34,280
Allura l-ebda diviżjoni numru sħiħ,
aħna qed biss istampar 0.1,

171
00:07:34,280 --> 00:07:37,100
imma aħna qed istampar dan
28 postijiet deċimali.

172
00:07:37,100 --> 00:07:41,810
U nikbru dan 0.1000, mazz sħiħ
ta 'żerijiet, 5 5 5, blah blah blah.

173
00:07:41,810 --> 00:07:45,495
Għalhekk il-kwistjoni hawnhekk hija għaliex ma
jistampaw li, minflok eżattament 0.1?

174
00:07:45,495 --> 00:07:46,620

175
00:07:46,620 --> 00:07:49,640
>> Allura r-raġuni hawn issa huwa
f'wiċċ l-ilma punt impreċiżjoni.

176
00:07:49,640 --> 00:07:53,410
Ftakar li float huwa biss 32 bits.

177
00:07:53,410 --> 00:07:57,540
Allura nistgħu jirrappreżentaw biss numru finit
tal galleġġjanti valuri tal-punti ma 'dawk 32

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00:07:57,540 --> 00:07:58,560
bits.

179
00:07:58,560 --> 00:08:01,760
Ukoll hemm finalment infinitament
ħafna valuri f'wiċċ l-ilma point,

180
00:08:01,760 --> 00:08:04,940
u hemm infinitament ħafna f'wiċċ l-ilma
valuri tal-punti fl bejn 0 u 1,

181
00:08:04,940 --> 00:08:07,860
u aħna qed ovvjament kapaċi
jirrappreżentaw valuri saħansitra aktar minn dak.

182
00:08:07,860 --> 00:08:13,230
Allura aħna għandna biex jagħmlu sagrifiċċji biex
tkun tista 'tirrappreżenta aktar valuri.

183
00:08:13,230 --> 00:08:16,960
>> Allura valur bħal 0.1, apparentement
ma nistgħux jirrappreżenta dak eżattament.

184
00:08:16,960 --> 00:08:22,500
Allura minflok li jirrappreżenta 0.1 nagħmlu l-
aħjar li nistgħu jirrappreżenta dan 0.100000 5 5

185
00:08:22,500 --> 00:08:23,260
5.

186
00:08:23,260 --> 00:08:26,306
U li pretty qrib, iżda
għal ħafna applikazzjonijiet

187
00:08:26,306 --> 00:08:28,430
għandek għalfejn tinkwieta dwar
f'wiċċ l-ilma punt impreċiżjoni,

188
00:08:28,430 --> 00:08:30,930
għaliex aħna biss ma tistax tirrappreżenta
punti kollha f'wiċċ l-ilma eżattament.

189
00:08:30,930 --> 00:08:32,500

190
00:08:32,500 --> 00:08:33,380
>> Mistoqsija 15.

191
00:08:33,380 --> 00:08:34,679
Ikkunsidra l-kodiċi hawn taħt.

192
00:08:34,679 --> 00:08:36,630
Aħna biss istampar 1 flimkien ma '1.

193
00:08:36,630 --> 00:08:38,289
B'hekk m'hemm l-ebda trick hawnhekk.

194
00:08:38,289 --> 00:08:41,780
1 flimkien ma '1 tevalwa sa 2, u
allura aħna qed istampar dik.

195
00:08:41,780 --> 00:08:42,789
Dan biss stampi 2.

196
00:08:42,789 --> 00:08:43,850

197
00:08:43,850 --> 00:08:44,700
>> Mistoqsija 16.

198
00:08:44,700 --> 00:08:49,450
Issa aħna qed istampar tal-karattru
1 flimkien mal-karattru 1.

199
00:08:49,450 --> 00:08:52,110
Allura għaliex ma dan ma
jistampaw l-istess ħaġa?

200
00:08:52,110 --> 00:08:57,680
Ukoll l-karattru 1 flimkien mal-karattru
1, il-karattru 1 għandu valur ASCII 49.

201
00:08:57,680 --> 00:09:04,840
Allura dan huwa verament qal 49 plus 49, u
finalment dan se jistampaw 98.

202
00:09:04,840 --> 00:09:06,130
Allura dan ma print 2.

203
00:09:06,130 --> 00:09:08,070

204
00:09:08,070 --> 00:09:09,271
>> Mistoqsija 17.

205
00:09:09,271 --> 00:09:11,520
Tlesti l-implimentazzjoni
tal fard hawn taħt b'tali mod

206
00:09:11,520 --> 00:09:14,615
li l-funzjoni jirritorna veru jekk
n hija fard u falza jekk n hija saħansitra.

207
00:09:14,615 --> 00:09:16,710

208
00:09:16,710 --> 00:09:19,330
Dan huwa skop kbir
għall-operatur mod.

209
00:09:19,330 --> 00:09:24,530
Allura aħna jieħdu argument n tagħna,
jekk n mod 2 huwa ugwali 1, ukoll

210
00:09:24,530 --> 00:09:28,030
dan ifisser li jinqasmu n
minn 2 kellhom bqija.

211
00:09:28,030 --> 00:09:33,270
Jekk n diviż bil 2 kellha kumplament, li
ifisser li n hija fard, hekk aħna ritorn veru.

212
00:09:33,270 --> 00:09:34,910
Else nerġgħu lura falza.

213
00:09:34,910 --> 00:09:39,070
Inti wkoll seta 'jsir n MOD 2 partijiet ugwali
żero, ritorn foloz, inkella ritorn veru.

214
00:09:39,070 --> 00:09:41,600

215
00:09:41,600 --> 00:09:43,640
>> Ikkunsidra l-funzjoni jirrikorri hawn taħt.

216
00:09:43,640 --> 00:09:46,920
Hekk jekk n hija inqas minn jew
ugwali għal 1, jirritornaw 1,

217
00:09:46,920 --> 00:09:50,430
ritorn inkella n żminijiet f 'n minus 1.

218
00:09:50,430 --> 00:09:52,556
Allura x'inhi din il-funzjoni?

219
00:09:52,556 --> 00:09:54,305
Ukoll, dan huwa biss il-
funzjoni fattorjali.

220
00:09:54,305 --> 00:09:55,410

221
00:09:55,410 --> 00:09:57,405
Dan huwa rappreżentat nicely
kif fattorjali n.

222
00:09:57,405 --> 00:09:58,720

223
00:09:58,720 --> 00:10:02,310
>> Allura mistoqsija 19 issa, irridu
jieħdu din il-funzjoni jirrikorri.

224
00:10:02,310 --> 00:10:04,530
Aħna rridu li jagħmilha iterattiv.

225
00:10:04,530 --> 00:10:05,874
Allura kif nistgħu nagħmlu dan?

226
00:10:05,874 --> 00:10:07,790
Ukoll għall-persunal
soluzzjoni, u għal darb'oħra hemm

227
00:10:07,790 --> 00:10:11,090
modi multipli li seta 'jsir
li, nibdew ma 'dan il-prodott int

228
00:10:11,090 --> 00:10:11,812
ugwali 1.

229
00:10:11,812 --> 00:10:13,520
U matul dan
għal loop, aħna qed tmur

230
00:10:13,520 --> 00:10:17,590
li għandha multiplikazzjoni prodott li finalment
jispiċċaw ma 'l-fattorjali sħiħa.

231
00:10:17,590 --> 00:10:21,870
Allura għal int i ugwali 2, i huwa
inqas minn jew ugwali għal n, i ++.

232
00:10:21,870 --> 00:10:24,130
>> Inti jista 'jistaqsi għaliex I ugwali 2.

233
00:10:24,130 --> 00:10:28,380
Ukoll, ftakar li hawnhekk għandna biex
kun żgur każ bażi tagħna hija korretta.

234
00:10:28,380 --> 00:10:32,180
Hekk jekk n hija inqas minn jew ugwali
għal 1, aħna qed biss jirritorna 1.

235
00:10:32,180 --> 00:10:34,830
Allura hawn, aħna jibdew fil i ugwali 2.

236
00:10:34,830 --> 00:10:39,090
Ukoll jekk i kienu 1, imbagħad the-- jew
jekk n kienu 1, allura l-għar loop

237
00:10:39,090 --> 00:10:40,600
ma tesegwixxi fil-livelli kollha.

238
00:10:40,600 --> 00:10:43,190
U hekk aħna kieku biss
prodott ritorn, li hija l-1.

239
00:10:43,190 --> 00:10:45,920
Bl-istess mod, jekk n kienu
xejn inqas minn 1--

240
00:10:45,920 --> 00:10:49,290
kieku kien 0, negattivi 1, whatever--
aħna'd xorta jirritorna 1,

241
00:10:49,290 --> 00:10:52,260
li huwa eżattament dak li l-
Verżjoni rikursivi qed tagħmel.

242
00:10:52,260 --> 00:10:54,660
>> Issa, jekk n hija akbar
minn 1, allura aħna qed tmur

243
00:10:54,660 --> 00:10:56,550
biex tagħmel mill-inqas wieħed
iterazzjoni ta 'dan loop.

244
00:10:56,550 --> 00:11:00,630
Mela ejja ngħidu n hija ta '5, allura aħna qed
se jagħmlu żminijiet prodott ugwali 2.

245
00:11:00,630 --> 00:11:02,165
Allura issa prodott huwa 2.

246
00:11:02,165 --> 00:11:04,040
Issa aħna qed tmur biex tagħmel
ħinijiet tal-prodott ugwali 3.

247
00:11:04,040 --> 00:11:04,690
Issa huwa 6.

248
00:11:04,690 --> 00:11:07,500
Ħinijiet Prodott ugwali 4, issa huwa 24.

249
00:11:07,500 --> 00:11:10,420
Ħinijiet Prodott ugwali 5, issa huwa 120.

250
00:11:10,420 --> 00:11:16,730
Hekk allura finalment, aħna qed jirritornaw
120, li huwa b'mod korrett 5 fattoriku.

251
00:11:16,730 --> 00:11:17,510
>> Mistoqsija 20.

252
00:11:17,510 --> 00:11:22,480
Dan huwa l-waħda fejn inti għandek timla
f'din it-tabella ma 'kull algoritmu partikolari,

253
00:11:22,480 --> 00:11:25,735
xi ħaġa li aħna stajt tidher, li
aċċessjonijiet dawn run algorithmic

254
00:11:25,735 --> 00:11:28,060
drabi dawn darbiet run asintotiku.

255
00:11:28,060 --> 00:11:33,270
Allura x'inhu algoritmu li
huwa omega ta '1, iżda O kbira ta' n?

256
00:11:33,270 --> 00:11:35,970
Allura jista 'jkun hemm infinitament
ħafna tweġibiet hawnhekk.

257
00:11:35,970 --> 00:11:39,790
Il-wieħed li aħna stajt tidher probabbilment l-aktar
spiss huwa biss tfittxija lineari.

258
00:11:39,790 --> 00:11:42,050
>> Hekk fil-każ aħjar
xenarju, il-punt aħna qed

259
00:11:42,050 --> 00:11:44,050
tfittex huwa fil-
bidu tal-lista

260
00:11:44,050 --> 00:11:47,400
u għalhekk omega ta '1 passi,
l-ewwel ħaġa li għandna jiċċekkjaw,

261
00:11:47,400 --> 00:11:49,740
aħna biss jirritorna minnufih
li sibna l-oġġett.

262
00:11:49,740 --> 00:11:52,189
Fl-agħar każ,
l-oġġett huwa fl-aħħar,

263
00:11:52,189 --> 00:11:53,730
jew l-oġġett ma tkunx fil-lista fil-livelli kollha.

264
00:11:53,730 --> 00:11:56,700
Hekk irridu tfittxija
l-lista sħiħa, kollha n

265
00:11:56,700 --> 00:11:58,480
elementi, u li C'est pourquoi huwa o ta n.

266
00:11:58,480 --> 00:11:59,670

267
00:11:59,670 --> 00:12:04,880
>> Allura issa huwa xi ħaġa li dawn, kemm
omega ta 'log n n, u O kbir ta' log n n.

268
00:12:04,880 --> 00:12:08,650
Ukoll l-aktar ħaġa rilevanti
Rajna hawnhekk huwa jingħaqdu sort.

269
00:12:08,650 --> 00:12:12,950
Allura jingħaqdu sort, ftakar,
huwa finalment Theta

270
00:12:12,950 --> 00:12:16,920
ta 'n log n, fejn theta hija definita
jekk kemm omega u O kbar huma l-istess.

271
00:12:16,920 --> 00:12:17,580
Kemm n log n.

272
00:12:17,580 --> 00:12:18,690

273
00:12:18,690 --> 00:12:21,970
>> X'hemm xi ħaġa li omega
ta 'n, u O ta' n kwadrat?

274
00:12:21,970 --> 00:12:23,990
Ukoll, għal darb'oħra hemm
tweġibiet possibbli multipli.

275
00:12:23,990 --> 00:12:26,440
Hawnhekk aħna jiġri li ngħidu sort bużżieqa.

276
00:12:26,440 --> 00:12:28,840
Sort inserzjoni wkoll jaħdem hawn.

277
00:12:28,840 --> 00:12:31,400
Ftakar dik it-tip bużżieqa
għandha li search fejn,

278
00:12:31,400 --> 00:12:34,630
jekk inti huma kapaċi jiksbu
permezz tal-lista sħiħa

279
00:12:34,630 --> 00:12:37,402
mingħajr il-bżonn li tagħmel
xi swaps, allura, ukoll,

280
00:12:37,402 --> 00:12:40,110
nistgħu immedjatament jirritorna dik
il-lista ġiet magħżula biex tibda bil.

281
00:12:40,110 --> 00:12:43,185
Hekk fil-xenarju aħjar,
huwa biss omega ta n.

282
00:12:43,185 --> 00:12:45,960
Jekk mhuwiex biss nicely
magħżula lista li tibda bil,

283
00:12:45,960 --> 00:12:48,270
allura għandna O ta 'n kwadrat swaps.

284
00:12:48,270 --> 00:12:49,330

285
00:12:49,330 --> 00:12:55,610
U finalment, aħna għandna sort għażla
għal n kwadrat, kemm omega u O. big

286
00:12:55,610 --> 00:12:56,850
>> Mistoqsija 21.

287
00:12:56,850 --> 00:12:58,870
X'hemm overflow integer?

288
00:12:58,870 --> 00:13:02,160
Ukoll għal darb'oħra, simili għal qabel,
aħna biss finitely ħafna bits

289
00:13:02,160 --> 00:13:04,255
biex jirrappreżentaw integer,
hekk forsi 32 bits.

290
00:13:04,255 --> 00:13:06,300

291
00:13:06,300 --> 00:13:09,180
Ejja ngħidu aħna għandna numru sħiħ ffirmata.

292
00:13:09,180 --> 00:13:12,800
Imbagħad finalment l-ogħla
numru pożittiv nistgħu jirrappreżentaw

293
00:13:12,800 --> 00:13:15,910
hija ta '2 għall-31 minus 1.

294
00:13:15,910 --> 00:13:19,370
Allura x'jiġri jekk nippruvaw
imbagħad inkrement li integer?

295
00:13:19,370 --> 00:13:25,320
Well, aħna qed tmur biex tmur minn 2 sa l-31 ta '
minus 1, it-triq kollha sa negattiv 2

296
00:13:25,320 --> 00:13:26,490
għall-31.

297
00:13:26,490 --> 00:13:29,470
Allura dan overflow numru sħiħ hija
meta inti żżomm inkrementazzjoni,

298
00:13:29,470 --> 00:13:32,330
u finalment inti ma tistax
jiksbu kwalunkwe ogħla u hija biss

299
00:13:32,330 --> 00:13:34,520
garżi it-triq kollha lura
madwar għal valur negattiv.

300
00:13:34,520 --> 00:13:35,850

301
00:13:35,850 --> 00:13:37,779
>> What about a overflow buffer?

302
00:13:37,779 --> 00:13:39,820
Allura buffer overflow--
tiftakar dak buffer huwa.

303
00:13:39,820 --> 00:13:41,000
Huwa biss blokki ta 'memorja.

304
00:13:41,000 --> 00:13:43,350
Xi ħaġa simili firxa hija buffer.

305
00:13:43,350 --> 00:13:46,120
Allura overflow buffer huwa meta
inti tipprova l-aċċess memorja

306
00:13:46,120 --> 00:13:47,880
wara t-tmiem ta 'dak array.

307
00:13:47,880 --> 00:13:50,410
Mela jekk għandek
firxa ta 'daqs 5 u int

308
00:13:50,410 --> 00:13:53,700
tipprova l-aċċess bracket firxa
5 jew kategorija 6 jew kategorija 7,

309
00:13:53,700 --> 00:13:56,610
jew xi ħaġa lil hinn mill-
aħħar, jew saħansitra xejn

310
00:13:56,610 --> 00:14:00,790
bracket firxa below-- negattiv 1--
kollha ta 'dawk huma tifwir buffer.

311
00:14:00,790 --> 00:14:02,810
Inti jmissu memorja b'modi ħżiena.

312
00:14:02,810 --> 00:14:04,090

313
00:14:04,090 --> 00:14:04,730
>> Mistoqsija 23.

314
00:14:04,730 --> 00:14:05,760

315
00:14:05,760 --> 00:14:09,100
Allura f'dan il-wieħed li għandek bżonn
biex jimplimentaw strlen.

316
00:14:09,100 --> 00:14:11,630
U aħna jgħidlek li inti tista '
jassumu s mhux se jkun null,

317
00:14:11,630 --> 00:14:13,790
sabiex inti ma għandekx
tagħmel xi kontroll għall null.

318
00:14:13,790 --> 00:14:16,190
U hemm modi multipli
li seta 'jsir dan.

319
00:14:16,190 --> 00:14:18,440
Hawnhekk aħna biss jieħdu l-sempliċi.

320
00:14:18,440 --> 00:14:21,780
Aħna tibda bil-counter, n. n hija
għadd kemm karattri hemm.

321
00:14:21,780 --> 00:14:25,560
Allura nibdew f'0, u allura aħna
jtenni fuq il-lista sħiħa.

322
00:14:25,560 --> 00:14:29,092
>> Huwa s bracket 0 ugwali għall-
karattru terminatur null?

323
00:14:29,092 --> 00:14:31,425
Ftakar aħna qed infittxu
il-karattru terminatur null

324
00:14:31,425 --> 00:14:33,360
biex jiddetermina kemm string tagħna huwa.

325
00:14:33,360 --> 00:14:35,890
Li ser jittermina
kwalunkwe string rilevanti.

326
00:14:35,890 --> 00:14:39,400
Allura huwa s bracket 0 ugwali
għall-terminatur null?

327
00:14:39,400 --> 00:14:42,850
Jekk mhuwiex, allura aħna qed tmur biex
tħares lejn bracket i 1, parentesi s 2.

328
00:14:42,850 --> 00:14:45,050
Aħna jibqgħu għaddejjin sakemm aħna
isibu l-terminatur null.

329
00:14:45,050 --> 00:14:48,580
Ladarba aħna ħadthom sabuha, allura n fih
it-tul totali tas-sekwenza,

330
00:14:48,580 --> 00:14:49,942
u nistgħu biss ritorn dak.

331
00:14:49,942 --> 00:14:51,180

332
00:14:51,180 --> 00:14:51,865
>> Mistoqsija 24.

333
00:14:51,865 --> 00:14:53,010

334
00:14:53,010 --> 00:14:56,050
Allura dan huwa l-waħda fejn inti
għandek tagħmel l-kummerċ off.

335
00:14:56,050 --> 00:14:59,810
Allura ħaġa waħda hija tajba fil waħda
mod, iżda b'liema mod huwa ħażin?

336
00:14:59,810 --> 00:15:02,980
Allura hawnhekk, jingħaqdu sort tendenza li
jkun aktar mgħaġġel milli sort bużżieqa.

337
00:15:02,980 --> 00:15:06,530
Wara li qal that-- tajjeb, hemm
huma tweġibiet multipli hawn.

338
00:15:06,530 --> 00:15:12,930
Iżda l-wieħed prinċipali huwa li sort bużżieqa
huwa omega ta n għal lista magħżul.

339
00:15:12,930 --> 00:15:14,950
>> Ftakar dik it-tabella aħna biss raw qabel.

340
00:15:14,950 --> 00:15:17,600
Allura bużżieqa xorta omega ta
n, ix-xenarju aħjar każ

341
00:15:17,600 --> 00:15:20,010
huwa huwa kapaċi li jmorru biss fuq
il-lista ladarba, jiddeterminaw

342
00:15:20,010 --> 00:15:22,270
ħej din hija ħaġa diġà
magħżula, u r-ritorn.

343
00:15:22,270 --> 00:15:25,960
Jingħaqdu sort, irrelevanti x'inhu
inti tagħmel, hija omega ta 'log n n.

344
00:15:25,960 --> 00:15:29,200
Allura għal-lista magħżula, bubble
sort għaddej biex tkun aktar mgħaġġla.

345
00:15:29,200 --> 00:15:30,870

346
00:15:30,870 --> 00:15:32,430
>> Issa dak dwar marbut listi?

347
00:15:32,430 --> 00:15:36,070
Allura lista marbuta jistgħu jikbru u tiċkien
li tajbin kif ħafna elementi kif meħtieġ.

348
00:15:36,070 --> 00:15:38,489
Wara li qal that-- hekk
normalment il-paragun dirett

349
00:15:38,489 --> 00:15:40,280
se jkun marbut
lista ma 'firxa.

350
00:15:40,280 --> 00:15:41,600

351
00:15:41,600 --> 00:15:44,050
Allura anke jekk arrays tista
faċilment jikbru u tiċkien

352
00:15:44,050 --> 00:15:47,130
li tajbin kif ħafna elementi
kif meħtieġ, lista marbuta

353
00:15:47,130 --> 00:15:49,600
meta mqabbel ma 'l array--
firxa għandha aċċess bl-addoċċ.

354
00:15:49,600 --> 00:15:52,960
Nistgħu indiċi fi kwalunkwe
element partikolari ta 'l-array.

355
00:15:52,960 --> 00:15:56,430
>> Allura għal-lista marbuta, ma nistgħux
biss jmorru għall-ħames element,

356
00:15:56,430 --> 00:16:00,260
għandna biex travers mill-bidu
sakemm aħna jiksbu l-ħames element.

357
00:16:00,260 --> 00:16:03,990
U li għaddej biex jipprevjenu lilna minn
tagħmel xi ħaġa simili tfittxija binarja.

358
00:16:03,990 --> 00:16:08,150
Taħdit ta 'tfittxija binarja, tfittxija binarja
tendenza li tkun aktar mgħaġġla minn tfittxija lineari.

359
00:16:08,150 --> 00:16:11,120
Wara li qal that--
hekk, ħaġa waħda possibbli

360
00:16:11,120 --> 00:16:13,380
hija li inti ma tistax tagħmel binarja
tfittxija fuq listi marbuta,

361
00:16:13,380 --> 00:16:14,730
inti tista 'biss tagħmel dan fuq arrays.

362
00:16:14,730 --> 00:16:18,030
Iżda probabbilment aktar importanti,
inti ma tistax tagħmel tfittxija binarja

363
00:16:18,030 --> 00:16:20,690
fuq firxa li mhix riżolta.

364
00:16:20,690 --> 00:16:23,990
Bil-quddiem jista 'jkollok bżonn biex issolvi
l-array, u biss jistgħu imbagħad

365
00:16:23,990 --> 00:16:25,370
inti tagħmel tfittxija binarja.

366
00:16:25,370 --> 00:16:27,660
Hekk jekk ħaġa tiegħek mhix
ssortjat li tibda bil,

367
00:16:27,660 --> 00:16:29,250
allura tfittxija lineari jista 'jkun malajr.

368
00:16:29,250 --> 00:16:30,620

369
00:16:30,620 --> 00:16:31,740
>> Mistoqsija 27.

370
00:16:31,740 --> 00:16:34,770
Sabiex jikkunsidraw il-programm hawn taħt,
li se tkun fil-slide li jmiss.

371
00:16:34,770 --> 00:16:37,790
U dan huwa dak fejn aħna qed
tmur jridu jiddikjaraw b'mod espliċitu

372
00:16:37,790 --> 00:16:39,980
il-valuri għall-varjabbli differenti.

373
00:16:39,980 --> 00:16:41,990
Mela ejja nħarsu lejn dak.

374
00:16:41,990 --> 00:16:43,160
>> Allura linja waħda.

375
00:16:43,160 --> 00:16:45,457
Għandna int x ugwali 1.

376
00:16:45,457 --> 00:16:47,040
Dik hija l-unika ħaġa li ġara.

377
00:16:47,040 --> 00:16:50,440
Allura fil-linja waħda, naraw fil tagħna
tabella, li y, a, b, u TMP huma kollha

378
00:16:50,440 --> 00:16:51,540
blokkjat.

379
00:16:51,540 --> 00:16:52,280
Allura x'inhi x?

380
00:16:52,280 --> 00:16:53,860
Well we biss sett huwa ugwali għal 1.

381
00:16:53,860 --> 00:16:55,020

382
00:16:55,020 --> 00:16:58,770
U mbagħad linja tnejn, ukoll,
naraw li y huwa stabbilit għal 2,

383
00:16:58,770 --> 00:17:00,550
u t-tabella hija diġà
mimlija għalina.

384
00:17:00,550 --> 00:17:03,040
Allura x hija l-1 u Y huwa ta '2.

385
00:17:03,040 --> 00:17:05,890
>> Issa, linja tlieta, aħna qed issa
ġewwa l-funzjoni tpartit.

386
00:17:05,890 --> 00:17:07,560
What did aħna jgħaddu biex tpartit?

387
00:17:07,560 --> 00:17:11,609
Aħna għadda ampersand x għall
a, u ampersand y għal b.

388
00:17:11,609 --> 00:17:15,160
Fejn il-problema qabel
iddikjara li l-indirizz ta 'x

389
00:17:15,160 --> 00:17:17,520
huwa 0x10, u l-indirizz ta 'y huwa 0x14.

390
00:17:17,520 --> 00:17:18,970

391
00:17:18,970 --> 00:17:21,909
Allura aub huma ugwali għal
0x10 u 0x14, rispettivament.

392
00:17:21,909 --> 00:17:23,670

393
00:17:23,670 --> 00:17:26,250
>> Issa fil-linja tlieta, liema huma x u y?

394
00:17:26,250 --> 00:17:28,554
Well, xejn ma nbidel
dwar xuy f'dan il-punt.

395
00:17:28,554 --> 00:17:30,470
Anki jekk dawn qed
ġewwa qafas munzell prinċipali,

396
00:17:30,470 --> 00:17:32,469
dawn ikunu għadhom l-istess
Valuri huma għamlu qabel.

397
00:17:32,469 --> 00:17:34,030
Aħna jkunx immodifika memorja.

398
00:17:34,030 --> 00:17:35,710
Allura x huwa 1, y hija ta '2.

399
00:17:35,710 --> 00:17:36,550

400
00:17:36,550 --> 00:17:37,050
Kull dritt.

401
00:17:37,050 --> 00:17:40,300
Allura issa aħna qal TMP int ugwali għal istilla a.

402
00:17:40,300 --> 00:17:44,410
Allura fil-linja erbgħa, kollox
huwa l-istess ħlief għall TMP.

403
00:17:44,410 --> 00:17:47,130
Aħna ma nbidlux xi valuri
ta 'xejn ħlief għall TMP.

404
00:17:47,130 --> 00:17:49,230
Aħna twaqqif TMP ugwali għal istilla a.

405
00:17:49,230 --> 00:17:50,620
X'inhu star a?

406
00:17:50,620 --> 00:17:56,240
Well, punti għal x, So istilla a
se x ugwali, li hija l-1.

407
00:17:56,240 --> 00:18:00,080
Allura kollox huwa kkupjata
isfel, u TMP huwa stabbilit għal 1.

408
00:18:00,080 --> 00:18:01,110
>> Issa l-linja li jmiss.

409
00:18:01,110 --> 00:18:03,380
Star a ugwali stilla b.

410
00:18:03,380 --> 00:18:10,000
Allura billi linja five-- sew għal darb'oħra, kollox
huwa l-istess ħlief kwalunkwe star a huwa.

411
00:18:10,000 --> 00:18:10,830
X'inhu star a?

412
00:18:10,830 --> 00:18:13,720
Well, aħna biss qal star a huwa x.

413
00:18:13,720 --> 00:18:16,400
Allura aħna qed jinbidlu x bħala ugwali għal star b.

414
00:18:16,400 --> 00:18:18,960
X'inhu star b? y. punti B sa y.

415
00:18:18,960 --> 00:18:21,030
Allura star b huwa y.

416
00:18:21,030 --> 00:18:25,140
Allura aħna qed jistabbilixxu x ugwali għal y,
u kull ħaġa oħra huwa l-istess.

417
00:18:25,140 --> 00:18:29,130
Allura naraw fil-filliera li jmiss li x issa huwa
2, u l-bqija huma biss kkupjati isfel.

418
00:18:29,130 --> 00:18:31,120
>> Issa fil-linja li jmiss, star b ugwali TMP.

419
00:18:31,120 --> 00:18:34,740
Well, aħna biss qal star b huwa y,
hekk aħna qed iffissar ugwali y għal TMP.

420
00:18:34,740 --> 00:18:37,450
Kollox huwa l-istess,
hekk kollox gets kkupjati isfel.

421
00:18:37,450 --> 00:18:42,050
Aħna qed iffissar y ugwali għal TMP, li hija
waħda, u kull ħaġa oħra huwa l-istess.

422
00:18:42,050 --> 00:18:43,210
>> Issa finalment, linja seba.

423
00:18:43,210 --> 00:18:44,700
Aħna qed lura fil-funzjoni ewlenija.

424
00:18:44,700 --> 00:18:46,350
Aħna wara tpartit huwa lest.

425
00:18:46,350 --> 00:18:48,972
Tlifna, b, u
PAT, iżda fl-aħħar aħna

426
00:18:48,972 --> 00:18:51,180
mhumiex jinbidlu xi valuri
ta 'xejn f'dan il-punt,

427
00:18:51,180 --> 00:18:52,800
aħna biss kopja x u r y.

428
00:18:52,800 --> 00:18:56,490
U naraw li xuy huma
issa 2 u 1 minflok ta '1 u 2.

429
00:18:56,490 --> 00:18:58,160
It-tpartit tkun wettqet b'suċċess.

430
00:18:58,160 --> 00:18:59,500

431
00:18:59,500 --> 00:19:00,105
>> Mistoqsija 28.

432
00:19:00,105 --> 00:19:01,226

433
00:19:01,226 --> 00:19:03,100
Ejja ngħidu li inti tiltaqa
l-messaġġi ta 'żball

434
00:19:03,100 --> 00:19:06,790
hawn taħt matul ħinijiet tal-uffiċċju
sena d-dieħla bħala CA jew TF.

435
00:19:06,790 --> 00:19:08,930
Parir kif jiffissaw kull wieħed minn dawn l-iżbalji.

436
00:19:08,930 --> 00:19:11,160
Referenza hekk undefined għall GetString.

437
00:19:11,160 --> 00:19:12,540
Għaliex jista inti tara dan?

438
00:19:12,540 --> 00:19:15,380
Ukoll, jekk student qed tuża
GetString fil-kodiċi tagħhom,

439
00:19:15,380 --> 00:19:20,310
huma jkunu kif suppost hash inklużi CS50
dot h biex tinkludi l-librerija CS50.

440
00:19:20,310 --> 00:19:22,380
>> Ukoll, liema do huma
ħtieġa li jiffissaw dan l-iżball?

441
00:19:22,380 --> 00:19:26,810
Dawn jeħtieġ li jagħmlu lcs50 sing fil-
linja ta 'kmand meta jkunu qed jikkompila.

442
00:19:26,810 --> 00:19:29,501
Hekk jekk dawn ma jgħaddu
lcs50 sing clang, dawn qed

443
00:19:29,501 --> 00:19:32,000
mhux ser ikollhom l-attwali
kodiċi li timplimenta GetString.

444
00:19:32,000 --> 00:19:33,190

445
00:19:33,190 --> 00:19:34,170
>> Mistoqsija 29.

446
00:19:34,170 --> 00:19:36,190
Impliċitament li tiddikjara
funzjoni librerija strlen.

447
00:19:36,190 --> 00:19:37,550

448
00:19:37,550 --> 00:19:40,360
Ukoll dan issa, dawn ma jkunux
għamlu l-hash xierqa jinkludu.

449
00:19:40,360 --> 00:19:41,440

450
00:19:41,440 --> 00:19:45,410
F'dan il-każ partikolari, il-fajl tal-header
li għandhom bżonn biex jinkludu huwa string dot h,

451
00:19:45,410 --> 00:19:48,710
u inkluż string dot h, issa
il student-- issa l-kumpilatur

452
00:19:48,710 --> 00:19:51,750
għandu aċċess għall-
dikjarazzjonijiet ta 'strlen,

453
00:19:51,750 --> 00:19:54,120
u jaf li kodiċi tiegħek
qed tuża strlen korrett.

454
00:19:54,120 --> 00:19:55,380

455
00:19:55,380 --> 00:19:56,580
>> Mistoqsija 30.

456
00:19:56,580 --> 00:20:00,240
Konverżjonijiet fil-mija aktar
minn argumenti dejta.

457
00:20:00,240 --> 00:20:01,540
Allura dak li huwa dan?

458
00:20:01,540 --> 00:20:06,470
Ukoll ftakar li dawn mija
signs-- kif dawn qed rilevanti għall printf.

459
00:20:06,470 --> 00:20:08,890
Allura fil-printf nistgħu percent--
nistgħu jistampaw xi ħaġa

460
00:20:08,890 --> 00:20:11,380
bħal fil-mija i backslash n.

461
00:20:11,380 --> 00:20:15,310
Jew nistgħu jistampaw bħal mija i,
ispazju, mija i, l-ispazju, mija i.

462
00:20:15,310 --> 00:20:18,950
Allura għal kull wieħed minn dawk
sinjali mija, għandna bżonn

463
00:20:18,950 --> 00:20:21,560
jgħaddu varjabbli fl-aħħar tal printf.

464
00:20:21,560 --> 00:20:26,980
>> Allura jekk aħna ngħidu paren printf mija
i backslash paren n-qrib,

465
00:20:26,980 --> 00:20:30,270
ukoll, aħna ngħidu li aħna qed
morna għall-istampa integer,

466
00:20:30,270 --> 00:20:33,970
iżda mbagħad ma ngħaddux printf
integer li attwalment jistampaw.

467
00:20:33,970 --> 00:20:37,182
Allura hawnhekk iżjed mija
konverżjonijiet minn argumenti tad-data?

468
00:20:37,182 --> 00:20:39,390
Li qal li għandna
mazz sħiħ ta 'percents,

469
00:20:39,390 --> 00:20:42,445
u aħna ma jkollhomx biżżejjed varjabbli
li attwalment timla f'dawk percents.

470
00:20:42,445 --> 00:20:44,850

471
00:20:44,850 --> 00:20:50,010
>> U mbagħad definittivament, għal mistoqsija 31,
definittivament mitlufa 40 bytes f'wieħed blokki.

472
00:20:50,010 --> 00:20:52,350
Allura dan huwa żball Valgrind.

473
00:20:52,350 --> 00:20:54,720
Dan huwa qal li
x'imkien fil-kodiċi tiegħek,

474
00:20:54,720 --> 00:20:59,010
għandek allokazzjoni li hu huwa 40
bytes kbir sabiex inti malloced 40 bytes,

475
00:20:59,010 --> 00:21:00,515
u int qatt meħlusa dan.

476
00:21:00,515 --> 00:21:02,480

477
00:21:02,480 --> 00:21:05,140
Ħafna probabbli inti biss bżonn
biex isibu xi nixxija memorja,

478
00:21:05,140 --> 00:21:07,650
u ssib fejn inti għandek bżonn
ħielsa dan il-blokk ta 'memorja.

479
00:21:07,650 --> 00:21:08,780

480
00:21:08,780 --> 00:21:11,910
>> U mistoqsija 32,
tikteb invalidu daqs 4.

481
00:21:11,910 --> 00:21:13,250
Għal darb'oħra din hija żball Valgrind.

482
00:21:13,250 --> 00:21:15,440
Dan ma għandek tagħmel
ma tnixxijiet memorja issa.

483
00:21:15,440 --> 00:21:20,750
Dan huwa, l-aktar likely-- I mean, huwa
xi tip ta 'drittijiet memorja invalidi.

484
00:21:20,750 --> 00:21:23,270
U l-aktar probabbli dan huwa xi
tip ta 'overflow buffer.

485
00:21:23,270 --> 00:21:26,560
Fejn għandek firxa, forsi
firxa integer, u ejja

486
00:21:26,560 --> 00:21:30,115
ngħid huwa ta 'daqs 5, u int
jippruvaw tmissx firxa bracket 5.

487
00:21:30,115 --> 00:21:34,150
Mela jekk inti tipprova tikteb lil dik
valur, li mhux biċċa ta 'memorja

488
00:21:34,150 --> 00:21:37,440
li inti fil-fatt ikollhom aċċess għal, u
hekk int ser tikseb dan l-iżball,

489
00:21:37,440 --> 00:21:39,272
qal tikteb invalidu d-daqs 4.

490
00:21:39,272 --> 00:21:42,480
Valgrind se jirrikonoxxu int
jippruvaw tmissx memorja inadegwatament.

491
00:21:42,480 --> 00:21:43,980
>> U li hija għal quiz0.

492
00:21:43,980 --> 00:21:47,065
Jien Rob Bowden, u dan huwa CS50.

493
00:21:47,065 --> 00:21:51,104