lap trinh can ban

8/14/2019 Lap Trinh Can Ban

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Lp Trnh Cn Bn

Tng Quan


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Mc ch Yu CuKhi nim v ngn ng lp trnhKhi nim v kiu d liuKiu d liu c cu trc (cu trc d liu)Khi nim v gii thutNgn ng biu din gii thutNgn ng s (lu ), s dng lu biu dincc gii thutTng quan v Ngn ng lp trnh C

Cc kiu d liu trong CCc lnh c cu trcCch thit k v s dng cc hm trong CMt s cu trc d liu trong C


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LP TRNH CN BN

Phn 1GII THIU V CU TRC D

LIU V GII THUTP.D.Nghip


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Ni dung chngT bi ton n chng trnhGii thut

Khi nim gii thut

Cc c trng ca gii thut Ngn ng biu din gii thut Mt s gii thut c bnCc cu trc suy lun c bn ca gii thut T gii thut n chng trnh

Kiu d liuKhi nim v ngn ng lp trnhChng trnh dch


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T Bi Ton n Chng Trnh

Cc bc gii bi ton bng my tnhM t cc bc gii bi tonV s x lVit chng trnh x l bng ngn ng giChn ngn ng lp trnh v chuyn chng trnht ngn ng gi sang ngn ng lp trnh

Thc hin chng trnh: nhp vo cc tham s,nhn kt qu


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Gii ThutKhi nim gii thutCc c trng ca gii thut

Ngn ng biu din gii thutMt s gii thut c bnCc cu trc suy lun c bn ca gii thut

T gii thut n chng trnh


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Khi Nim Gii ThutV d:Hon i cht lng trong 2 bnh A (ncmm) v B (ru):

Yu cu phi c thm mt bnh th ba gi l bnh C.

Bc 1: ru t bnh A sang bnh C.Bc 2: nc mm t bnh B sang bnh A.Bc 3: ru t bnh C sang bnh B.

Gii thut l mt dy cc thao tc trn nhng d liu vo sao cho sau mt hu hn bc ta thu c kt qu ca bi ton .


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Cc c Trng Ca Gii ThutTnh kt thc

S bc l hu hnTnh xc nh

My phi thc hin c Cho cng kt qu trn cc my khc nhau

Tnh ph dng

Tnh hiu quThi gianTi nguyn my


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Ngn Ng Biu Din GiiThut

Ngn ng t nhinNgn ng s

Ngn ng gi


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Ngn Ng T NhinL ngn ng ca chng taV d:Gii thut gii phng trnh bc nhtax+b=0.

Bc 1: Nhn gi tr ca cc tham s a, b.

Bc 2: Xt gi tr caa xem c bng 0 hay khng?Nu a=0 th lm bc 3, nu a khc khng th lm bc 4.

Bc 3: (a bng 0) Nu b bng 0 => pt v s nghim.Nu b khc 0 => pt v nghim.

Bc 4: ( a khc 0) Ta kt lun phng trnh cnghim x=-b/a.


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Ngn Ng S (1)M t gii thut bng cc s hnh khi c(quy c trc)


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Ngn Ng S (2)V d:Dng lu biu din gii thut tm UCLNnh sau:


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Mt S Gii Thut C Bn (1)V d 1:Yu cu:

Nhp vo 1 dy n shng a1, a2, .., an

Tnh tng S:S= a1 + a2 + a3 + ... + anIn S ra mn hnh


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Mt S Gii Thut C Bn (2)V d 2:Yu cu:

Nhp vo 2 s a v b l2 h s ca pt: ax+b=0

Cho bit nghim caphng trnh.


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Cc Cu Trc Suy Lun C BnCa Gii Thut (1)

Gii thut c thit k theo3 cu trc suy lun c bn:

Tun t (Sequential) :Cc cng vic c thc hin tun t, cng vic ny ni tipcng vic kia.

Cu trc la chn (Selection)La chn mt cng vic thc hin cn c vo mt iu kin

no Cu trc 1 : Nu < iu kin> (ng) th thc hin Cu trc 2 : Nu < iu kin> (ng) th thc hin ,ngc li (iu kin sai) th thc hin Cu trc 3 : Trng hp < i> thc hin


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Cc Cu Trc Suy Lun C BnCa Gii Thut (2)

Cu trc lp (Repeating)Lp lithc hin mt cng vickhng hoc nhiuln cn c vo mt iu kin no .C 2 dng nh sau:

Lp vi s ln xc nh Lp vi s ln khng xc nh


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T Gii Thut n ChngTrnh

C 2 u l tp cc ch th (instruction) lmth no gii quyt 1 cng vic (task).Gii thut

Ni chuyn vi con ngi, d hiu.Dng ngn ng n gin (English) khng vit bng m.

Chng trnhNi chuyn vi my tnh.C th c xem nh 1 din t hnh thc (formal expression) ca 1 gii thut.


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Kiu D LiuV d:

int x,y;float r=3.25;

Kiu d liu l mt tp hp cc gi tr c cng mt tnh cht v tp hp cc php ton thao tc trn cc gi tr .C 2 loi

Kiu d liu s cpKiu d liu c cu trc


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Kiu D Liu S CpKiu d liu s cp l kiu d liu m gi tr ca n l n nht.

V d: Kiuint trong Cl kiu s cpgm cc s nguyn t -32768..32767

v cc php ton: +, -, *, /, %


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Kiu D Liu C Cu TrcKiu d liu c cu trc l kiu d liu mcc gi tr ca n l s kt hp ca cc gi tr khc.

V d : Kiu chui k t trong C.l kiu c cu trc.V d: char *chuoi = Chao cac ban!;


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Khi Nim V Ngn Ng LpTrnh

Ngn ng lp trnh l mt ngn ng dng vit chng trnh cho my tnhTa c th chia ngn ng lp trnh thnh ccloi sau:

Ngn ng my Hp ng Ngn ng cp cao


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Ngn Ng My (machinelanguage)

L cc ch th di dngnh phn, can thip trctip vo trong cc mchin t.C th c thc hinngay khng cn quabc trung gian no.Tuy nhin chng trnh

vit bng ngn ng myd sai st, cng knh vkh c, kh hiuv tonnhng con s 0 v 1.

3

Machine Language

10100110 01110110

00100110 00000000

11111010 11111010

01001110 10100110

11100110 10010110

11001110 00101110

10100110 01001110

11111010 01100110

01001110 10000110

etc...


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Hp Ng (Assembly language)Bao gm tn cc cu lnh vquy tc vitcc cu lnh .Tn cc cu lnh bao gm haiphn:

Phn m lnh (English) ch php ton cn thc hinPhn a ch cha ton hng ca php ton .

my thc hin c mt chng trnh vit bng hp ng th chng trnh phi c dch sang ngn ng my . Cng c thc hin vic dch c gi l Assembler .

Assembly Language

MOV AL,a; chuyn gi tr a vo thanh ghi

; AL ADD AL,b ; Cng gi tr ca thanh ghi AL; vi gi tr b


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Ngn Ng Cp Cao (High level language )

Rt gn vi ngn ng con ngi.

Mt chng trnh vit bng ngnng cp cao c gi l chngtrnh ngun(source programs).

my tnh "hiu" v thc hinc cc lnh trong chng trnhngun th phi c mtchngtrnh dch dch chng trnhngun thnh dng chng trnh c kh nng thc thi.


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Chng Trnh Dch c dng chuyn mtchng trnhngun sang chng trnh ch.C 2 dng:

Thng dch (interpreter):Dch tng lnh mt, dch ti u thc hin ti .V d: ngn ng LISP.

Bin dch (compiler):Dch ton b chng trnh ngun thnh chng trnhch ri sau mi thc hin.V d: Pascal, C...


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Ht chng


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LP TRNH CN BN

Phn 2 - Chng 1GII THIU V NGN NG C& MI TRNG TURBO C 3.0

PDNghip


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Ni dung

Tng quan v ngn ng lp trnh CLch sNhng c im ca C

Mi trng lp trnh Turbo C


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Lch S (1)Ngn ng C c thit k bi Dennis Ritchiephng th nghim Bell vo u nhng nm1970.S pht trin ca C da trn cc ngn ng c:

ALGOL 60 (1960),CPL (Cambridge, 1963),BCPL (Martin Richard, 1967),B (Ken Thompson, 1970)

C l ngn ng lp trnh cp cao , c s dng rtph bin lp trnh h thng cng vi Assembler v pht trin cc ng dng, d rng ang c schuyn i sang dng C++.

90% ca UNIX c vit bng C


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Lch S (2)

DennisRitchie(tri)vKen Thompson trc h thngPDP-11 vi 2text-terminal(1972)


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Lch S (3)Nm 1978, DennisRitchiev Brian Kernighan xut bn 1

quyn sch m t ngnng C.

Dennis Ritchie (tri) v Kernighan


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Lch S (4)C c chun ha vo nm 1989 bi ANSI(American National Standards Institute),c bit nh ANSI C. c chun ha ISO (International standard) nm 1990 (chun ny cng c ANSI chpnhn v c bit nh C89)

c cp nht nm 1995 (C95 ) v 1999(C99).


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Nhng c im ca C (1)Tnh c ng (compact) :

C ch c 32 t kha chun v40 ton t chun.

Tnh cu trc (structured) : C c mt tp hp nhng ch th lp trnh:cu trc lachn, lp, n gin d hiu.

Tnh tng thch (compatible) : C c b tin x lvCc th vin chun v cng phong phNn khi chuyn t my tnh ny sang my tnh khc ccchng trnh vit bng C vn hon ton tng thch.


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Nhng c im ca C (2)Tnh linh ng (flexible) :

C php rt uyn chuyn, chp nhn nhiu cch th hinC th thu gn kch thc ca m lnh

Lm chng trnh chy nhanh hnBin dch (compile) :

C cho php bin dch nhiu tp tin chng trnh ring rthnh cc tp tin i tng (object)v

Lin kt (link) cc i tng li vi nhau thnh mtchng trnh c th thc thi c (executable) thng nht


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Mi trng lp trnh Turbo CTurbo C do hng Borlandcung cp.C cc chc nng: son tho chng trnh,dch, thc thi chng trnh, Phin bn c s dng y l Turbo C3.0


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Gi Turbo C


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Son tho chng trnh mi Vo menu File ->New

G chng trnh vo

#include

#includeint main (){

char ten[50];printf(Xin cho biet ten cua ban !);scanf(%s,ten);printf(Xin chao ban %s,ten);getch();return 0;

}

Ghi h h


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Ghi chng trnh ang sontho vo a

S dng File->Save hoc g phm F2Lnh Save As lu chng trnh vi tn khc

Tn hin ti (tnc)

Tn mi ( k ctn th mc)


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Qui tc t tn tp tin (file)Theo quy tc t tn tp tin ca DOS.Tn ca tp tin gm 2 phn:phn tn v phn m rng.

Phn tn:Bt u l 1 k t t a..z (khng phn bit hoa thng).Theo sau c th l cc k t t a..z, cc k s t 0..9 hay dugch di (_), phn ny di ti a l 8 k t.

Phn m rng:Di ti a 3 k t.

V d:Tn ng: CHAO.C, baitap2.c, chao_ban.cTn sai: 1CHAO.C, chao+ban.c

Th hi h h M


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Thc hin chng trnh + Mmt chng trnh+ Thot

Thc hin chng trnhNhn Ctrl-F9hoc vo menuRun->Run

M mt chng trnh ctrn aVo menu File->Openhocnhn F3

Thot khi Turbo CVo menu File->Exithocnhn Alt-X


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Cc lnh trn menu OptionDirectories:

Include directories: chacc tp tin ta mun a vochng trnh (file .h trongdng #include).

Library directories: chacc tp tin th vin (file .lib)Output directory: chacc tp tin i tng .objv .exe sau khi bin dchchng trnh.

Source directories: chacc tp tin ngun (.obj v.lib).

Environment: dng thit lp mi trng lmvic.


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Ht chng


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LP TRNH CN BN

Phn 2 - Chng 2CC THNH PHN C BN

CA NGN NG CP.D.Nghip


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Ni dung chng nyB ch vit trong CCc t kha

Cp du ghi ch thchCc kiu d liu s cp chunTn v hng

Bin v biu thcCu trc ca mt chng trnh C


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B ch vit trong CB ch vit trong ngn ng C bao gm cck t sau:

26 ch ci latinh ln A,B,C...Z

26 ch ci latinh nh a,b,c ...z.10 ch s thp phn 0,1,2...9.Cc k hiu ton hc: +, -, *, /, =, , (, )Cc k hiu c bit: :. , ; " ' _ @ # $ ! ^ [ ] { } ...Du cch hay khong trng.

Phn bit ch in hoa v in thng


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Cc t kha trong CT kha l cc t dnh ring ca C.Ta khng c dng t kha t cho cc tnca ring mnh.


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Cp du ch thch (comment)

Khi bin dch cc phn ch thch b b quaDng /* v */: ch thch di nhiu dngDng //: ch thch ch 1 dng

#include #includeint main (){

char ten[50]; /* khai bao bien tenkieu char 50 ky tu */

printf(Xin cho biet ten cua ban !);scanf(%s,ten); /*Doc vao 1 chuoi la ten ban*/printf(Xin chao ban %s\n ,ten);//Dung chuong trinh, cho go phimgetch();return 0;

}

C ki d li h


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Cc kiu d liu s cp chuntrong C

Kiu s nguyn (integer)Kiu s thc (real)


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Kiu s nguyn c dng lu cc gi tr nguyn hay cn gil kiu m c.

Kiu s nguyn 1 byte (8 bits)

Kiu s nguyn 2 bytes (16 bits)

Kiu s nguyn 4 byte (32 bits)


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Kiu s thc c dng lu cc s thc hay cc s c duchm thp phn

KiuvoidMang ngha l kiu rng khng cha gi tr g cV d: voidmain(){

.}


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Dng sizeof()Kch thc 1 kiu c th c xc nh lcchy chng trnh (runtime), dng sizeof:

V d: sizeof(double) =>8(byte)sizeof(long double)=>10(byte)


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Kiu enum (1)enum gn ging vi tin x l#define.N cho php ta nh ngha 1 danh sch cc b danh (aliase) trnh by cc s nguyn.V d:

#define MON 1#define TUE 2#define WED 3

c th dng enum:

enum week { Mon=1, Tue, Wed, Thu, Fri Sat, Sun}days; u im ca enum so vi #define l n c phmvi (scope), ngha l 1 bin ch c tc dng trongkhi (block) n c khai bo.


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Kiu enum (2)


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Kiu enum (3)


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Tn v hng trong CTn (identifier)

c dng t cho chng trnh, hng, kiu,bin, chng trnh con, ...C 2 loi:

Tn chun : l tn do C t sn nh tn kiu: int,char, float,; tn hm: sin, cos...Tn do ngi lp trnh t t.


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Ch khi t tn


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Tn do ngi lp trnh t tV d:

Tn t hp l: Chieu_dai, Chieu_Rong, Chu_ViTn khng hp l:Do Dai, 12A2

Phi tun th quy tc:S dng b ch ci, ch s v du gch di (_)Bt u bng mt ch ci hoc du gch di.Khng c khong trng gia tn.Khng c trng vi t kha.

di ti a ca tn l 32 k t, tuy nhin cn t sao cho rrng, d nhn bit v d nh.Khng cm vic t tn trng vi tn chun nhng khi ngha ca tn chun khng cn gi tr na.


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Hng (Constant) L i lng khng itrong sut qu trnh thc thichng trnh

=> khng th gn lI gi tr cho hng

Hng c th l:1 con s1 k t1 chui k t


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Hng s thc Gi tr kiu:float, double, long double2 cch th hin

Cch 1 : vit thng thng

V d:123.34 -223.333 3.00 -56.0Cch 2 : vit theo s m hay s khoa hc

Mt s thc c tch lm 2 phn (phn cchbi e/E)

Phn gi tr: nh cch 1Phn m: l mt s nguyn

V d:1234.56e-3 = 1.23456 (l s 1234.56*10-3)

-123.45E4 = -1234500 ( l -123.45*104)


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Hng s nguyn (1)Hng s nguyn 2 byte (int) hthp phn

S dng 10 k s 0..9V d:

123 (mt trm hai mi ba)

-242 (tr hai trm bn mi hai)Hng s nguyn 2 byte (int) hbt phnS dng 8 k s 0..7Cch biu din:0S bt phn : 0dndn-1dn-2d1d0 ( di c gi tr t 0..7)

=> gi tr:

V d:020=2*81 + 0*80 =(16)10

=

n

i

i

id

0

8*


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Hng s nguyn (2)Hng s nguyn 2 byte (int) hthp lc phn

L kiu s nguyn dng:10 k s 0..9 v6 k t A, B, C, D, E ,F

Cch biu din:0xS thp lc phn : 0xd ndn-1dn-2d1d0

=> Gi tr thp phn= V d:

0x345=3*162 + 4*161 + 5*160 = (837)10 0x2A9= 2*162 + 10*161 + 9*160= (681)10

=

n

i

i

id

0

16*


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Hng s nguyn (3)V d: Kt qu ca chng trnh sau l gi?


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Hng s nguyn (4)Hng s nguyn 4 byte (long)

c biu din nh s int trong h thp phnnhng km theo k t l hoc L.

V d: 45345L hay 45345l hay 45345


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Hng k t (char)V d : a, A, 0, 9L 1 k t c vit trongcp du nhy n ().Mi mt k t tng ngvi 1 gi tr trong bng mASCII.Hng k t cng c xemnh tr s nguyn.Chng ta c th thc hincc php ton s hc trn 2

k t (dng gi tr ASCII cachng)ASCII= American StandardCode for InformationInterchange


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Hng chui k tV d: Ngon ngu lap trinh CL 1 chui hay 1 xu k t c t trong cp du nhykp ().

Ch : : chui rng - khng c ni dungKhi lu tr trong b nh, mt chui c kt thc bng k tNULL (\0: m Ascii l 0).

biu din k t c bit bn trong chui ta phi thm du \ phatrc.

V d: VitI\m a student cho Im a student VitDay la ky tu \dac biet\ cho Day la ky tu dac biet

Bin v Biu thc (variable


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Bin v Biu thc (variableand expression)

Bin dng cha d liu trong qu trnh thc hinchng trnh.Gi tr ca bin c th b thay i.C php khai bo bin:

Danh sch cc tn bin cch nhau bi du phy ;

Khi to gi tr cho bin lc


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Khi to gi tr cho bin lckhai bo

V d:

Cch vit gi tr cho bit lun kiu ca n:

Ch : 8864L c kiulong, cn 8864 c kiuint


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V tr khai bo bin (1)Bin ngoi

c t bn ngoi tt ccc hm

nh hng n ton bchng trnh (bin toncc)


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V tr khai bo bin (2)Bin trong

c t bn tronghm, chng trnh

chnh hay mt khilnhnh hng n hm,chng trnh haykhi lnh cha n(bin cc b).


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Biu thc (1)V d:

(-b + sqrt(Delta))/(2*a)Biu thc l mt s kt hp gia

Cc ton t (operator) v

Cc ton hng (operand)Cc loi ton t trong C

Ton t s hcTon t quan h v logicTon t BitwiseTon t ?Ton t con tr & v *Ton t du phy


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Cc ton t s hc (1)


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Cc ton t s hc (2)

Tng v gim (++ & --)++x hay x++ gingx = x + 1

--x hay x-- gingx = x 1 Tuy nhin:

x = 10;

y = ++x; //y = 11, x=11

Cn:x = 10;

y = x++; //y = 10, x=11


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Cc ton t s hc (3)

u l s khc nhau?x++tr vgi tr hin hnh ca x v sau tng x++x tng x trc v sau tr v gi tr mi ca x

Biu thc Boolean (boolean


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Biu thc Boolean (booleanexpression)

Ch ! Khng c kiuBoolean r rng trong C (iu ny c gii thiu C99). Thay vo C dng cc gitr nguyn tng trng cho gi tr Boolean, vi quic:

Ch ! C dng =cho php gn, v dng ==cho phpso snh . N tr v1 nu bng v 0 nu ngc li

false Gi tr 0

true Bt k gi tr no ngoi tr 0

Cc ton t quan h v cc ton


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Cc ton t quan h v cc tont Logic (1)

Cc php so snh sau to ra cc biu thc logic cgi tr kiu Boolean



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V d:

Cc biu thc logic tr v0 nu false(sai)1 nu true(ng)



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Bng chn tr cho cc ton t Logic

Th t u tin

V d: 10>5&&!(10


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Cc ton t BitwiseTon t Bitwise gip kim tra,gn hay thay i cc bit tht strong 1 byte ca word.Ch dng cho kiuchar v int.


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Ton t ?Ton t ? thc hin nh lnh if-else.C php:

E1 ? E2 : E3V d: X = (10 > 9) ? 100 : 200;

=>X=100

X = (10 >15 )? 100 : 200;=>X=200


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Ton t con tr & v *V d:

int *p; //con tro so nguyenint count=5, x;

p = &count;=>t vo bin m a ch b nh ca bin count

Ton t * tr v ni dung ca nh m mt con tr

ang ch voV d:

x = *p; // x=5


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Ton t du phyV d:

x = (y=3,y+1);Trc ht gn 3 cho y ri gn 4 cho x.

c s dng kt hp cc biu thc li vinhau.Bn tri ca du (,) lun c xem l kiuvoid.Biu thc bn phi tr thnh gi tr ca tng ccbiu thc c phn cch bi du phy.


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Tng kt v u tin

Tng kt v u tin


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Php gn c vit gn li x= x y;

c th c vit gn li (short form):

Cc tp tin th vin thng


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p gdng

stdio.h : nh ngha cc hm vo/ra chun (standardinput/output):printf(), scanf(), getc(), putc(), gets(), puts(), fflush(),fopen(), fclose(), fread(), fwrite(), getchar(), putchar(), getw(),putw()conio.h : nh ngha cc hm vo ra trong ch DOS: clrscr(),getch(), getche(), getpass(), cgets(), cputs(), putch(), clreol(),math.h : nh ngha cc hm tnh ton: abs(), sqrt(), log(). log10(),sin(), cos(), tan(), acos(), asin(), atan(), pow(), exp(),alloc.h: nh ngha cc hm lin quan n vic qun l b nh:calloc(), realloc(), malloc(), free(), farmalloc(), farcalloc(), farfree(),io.h: nh ngha cc hm vo ra cp thp: open(), _open(), read(),

_read(), close(), _close(), creat(), _creat(), creatnew(), eof(),filelength(), lock(),graphics.h : nh ngha cc hm lin quan n ha: initgraph(),line(), circle(), putpixel(), getpixel(), setcolor(),

Cu trc ca 1 chng trnh C


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g(1)

Cu trc mt chng trnh CTin x l v bin dchPrototype

Cc tp tin th vin thng dng

Cu trc ca 1 chng trnh C


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g(2)

Chngtrnhchnh

Ci tcchm

Cc ch th tinx l

nh nghakiu mi

Prototype

Khai bobin

ngoi

Tin x l v bin dch (preprocess


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Tin x l v bin dch (preprocessand compile)

Cc ch th nh hng (directive):#include, #define

C th cha cc lnh phc tp nh if-else.B tin x l (preprocessor) sthng dch ccdirective v xa b n trc khi cung cp cho trnhbin dch C.


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#define#define khai bo mt tnmacro (macro symbol).Sau , mi ln tn

macro ny xut hin, ns c thay th bi gitr ca n.

Chia chng trnh ra cc


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gmodule (1)

1 chng trnh phc tp c th c chia ra vi module

Chia chng trnh ra cc


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gmodule (2)

Vn : testmodule.c phi bitcc prototype ca foor v bar .Gii php 1 (t):

Chn tay cc prototype vo cc file.c c dng n.Bt li: Mi khi prototype b thayi => phi chnh li prototype trongtt c cc file .c dng n.

Gii php 2 (tt): Lu cc prototype vo 1 file ringbit mymodule.h (h: header).Dng #include mymodule.h ucc chng trnh c dng n.


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#includeVi #include, b tin x l s thm v thay th token#include filename bng ni dung ca filename.

Cc header file s c tm u?#include :tm file.h trong th mc c xc nhtrong INCLUDE DIRECTORIES. Hoc trong /usr/include (linux)#include C:\\TC\\file.h: tm file.h trong ng dn


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Header fileCc header file c th cha:

Prototype cho cc hm (function) nh ngha kiu (structs, unions,

enums, typedefs)(nh ngha cc class trong C++)#define macro#pragma cho compiler

Cc bin ton ccCi t trc tip cc hm


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Ht chng


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LP TRNH CN BN

Phn 2 - Chng 3CC CU LNH N

TRONG CP.D.Nghip


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Ni dung chng nyCu lnh

Khi nim cu lnhPhn loi

Cc lnh nLnhgnLnhnhp gi tr t bn phm cho binLnhxut gi tr ca biu thc ln mn hnh


99/290

Khi nim cu lnh1 cu lnh xc nh 1 cng vic m chngtrnh phi thc hinKt thc bi;


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Phn loiC 2 loi

Lnh nKhng cha 1 lnh no khcGm: lnhgn, nhp, xut

Lnh c cu trcCha cc lnh khcGm:

cu trc iu kinr nhnhcu trc iu kinla chncu trc lpcu trc lnh hp thnh


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Cc lnh nLnh gnLnh nhp gi tr t bn phm cho binLnh xut gi tr ca biu thc ln mn hnh


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Lnh gn (3)Thng th c s chuyn i kiu t ng nu c th.

Chuyn c


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Lnh gn (4)Kt qu chng trnh sau l g?


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Lnh gn (5)Trong C, cc chuyn i kiu sau c lm t ng.

Nhng chuyn i trn m bo khng lm mt i s chnh xc(loss of precision).Vic chuyn i theo cc hng khc c th lm mt s chnh xcV d:

h ( )


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Lnh gn (6)p kiu (casting type)

Lnh nhp gi tr t bn phmh b ( )


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cho bin (1)scanf c d liu t bn phm v gn vo bin

Chui nh dng (format string): qui nh kiu dliu, cch biu din, rng, s ch s thp phn,

Lnh nhp gi tr t bn phmh bi (2)


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cho bin (2)scanf phi lu gi tr vo 1 bin

scanf(%d,anInt): khng ng, v anInt xc nh gitr hin hnh ca 1 bin.scanf(%d,&anInt): ng, v a ch ca anInt c xc nh.

V d D S d d I


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V d - Dng Standard Input

Lnh xut gi tr ca biu thcl h h ( )


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ln mn hnh (1)

Cn t nht 1 i s. i s u tin l 1 chuiChui c th cha:

V d:

Output

Lnh xut gi tr ca biu thcl h h (2)


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ln mn hnh (2)Nu mun in ra cc bin v biu thc, ta truyn n voprintf nh cc i s.Cc nh dng (format) khc nhau cho cc kiu gi trkhc nhau (dng %).

Lnh xut gi tr ca biu thcl h h (3)


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ln mn hnh (3)

Cc nh dng:

V d O C


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V d - Output t CHt chng

Gii th h th i tf


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Gii thch thm v printf


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Ht chng


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LP TRNH CN BN

Phn 2 - Chng 4CC LNH C CU TRC

P.D.Nghip

Ni d h


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Ni dung chng ny

Khi lnh trong CCu trc r nhnhCu trc la chnCu trc vng lpCc cu lnh c bit

Khi l h t g C (1)


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Khi lnh trong C (1)

L 1 dy cc khai bo cng vi cc cu lnh ntrong cp du ngoc mc{ v }.

Khi l h t g C (2)


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Khi lnh trong C (2)

1 khi lnh c th cha nhiu khi lnh khc gl khi lnh lng nhau(khng hn ch).

Ph i bi


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Phm vi cc binC th khai bo cc bin cngtn trong cc khi. Nu mt bin c khai bo bnngoi khi lnh v khng trngtn vi bin bn trong khi lnhth n cng dng c bn trongkhi.Mt khi lnh con c th sdng cc bin bn ngoi, nhngiu ngc li khng ng.

C trc r nhnh (if)


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Cu trc r nhnh (if)

Statement c thc hin nu boolean_expressionc gi trng (true), !=0.

Khielsel ty chn

boolean_expression !=0 => Statement1 c thc hin boolean_expression ==0 => Statement2 c thc hin

V d Lnh if


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V d - Lnh if #include

#include

int main (){float a;

printf("Nhap a = "); scanf("%f",&a);

if (a !=0 )

printf("Nghich dao cua %f la %f",a,1/a);

getch();return 0;

}

V d Lnh if else


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V d - Lnh if-else#include

#include

int main (){

float a;

printf("Nhap a = "); scanf("%f",&a);if (a !=0 )

printf("Nghich dao cua %f la %f",a,1/a);

else

printf(Khong the tim duoc nghich dao cuaa);

getch();

return 0;

}

Cu lnh v khi lnh


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Cu lnh v khi lnhC cho php nhm cc cu lnh lin tip vo 1 khi.1 khi lnh c th c dng nh 1 lnh n.V d:

Nhm ln khi dng if


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Nhm ln khi dng if

Chng trnh trn sai u?

Ch khi dng if else


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Ch khi dng if-elseCu lnhif-elselng nhauelse s kt hp vi if gn nht cha c elseTrong trng if bn trong khng celseth phi vit ntrong cp du{} trnh s kt hp else if sai.V d

Cu trc la chn(switch case) (1)


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(switch-case) (1)C cung cp 1 cu trc p - dng 1 dy cc cu lnhif .


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Cu trc la chn(switch case) (3)


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(switch-case) (3)

C php:Tnh gi tr ca biu thcexpr trc. Nu gi trexpr bngvalue1th thchinstatement_sequence1ri thot.

Nu gi trexpr khcvalue1th sosnh n vivalue2, nu bngvalue2 th thc hinstatement_sequence2rithot.C nh th, so snh ti gi trn.

Nu tt c cc php so snh trn usai th thc hindefault_statementsca trng hpdefault .


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V d switch case (1)


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V d - switch-case (1)

V d switch case (2)


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V d - switch-case (2)

In ra s ngyca 1 thng

Cu trc lp


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Cu trc lpCho php lp li thc hin 1 cng vic nhiu ln.C 2 loi:

Lp vi s ln xc nh

for Lp vi s ln khng xc nhwhiledo-while

Vng lp for (1)


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Vng lp for (1)

Th t thc hin:B1: Tnh gi trbiu thc 1B2: Tnh gi trbiu thc 2

Nu gi trbiu thc 2 lsai (==0)=> thot khifor Nu gi trbiu thc 2 lng (!=0)=> thc hin

B3: Tnh gi tr biu thc 3ri quay liB2

for (Biu thc 1; biu thc 2; biu thc 3) ;

Vng lp for (2)


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Vng lp for (2)

Vng lp for (2)


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Vng lp for (2)

Chng trnh in dy s nguyn t 1..10

output

Vng lp for (3)


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Vng lp for (3)Nhp s nguyn n. Tnh tng cc s nguyn t 1..n.

output

Vng lp while (1)


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Vng lp while (1)

:c th l 1 culnh hay 1 khi lnh.Cc bc thc hin:- Kim tra Biu thc iu

kin trc.- Nu iu kinsai (==0)th

thotkhi lnh while.- Nu iu kinng (!=0)th thc hin cng vicriquay li kim tra iu kintip.

while( Biu thc iu kin) ;

Vng lp while (2)


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Vng lp while (2)


output

Vng lp while (3)


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Vng lp while (3)Nhp s nguyn n. Tnh tng cc s nguyn t 1..n.

output

Vng lp do-while (1)


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Vng lp do while (1)

:c th l 1 cu lnhhay 1 khi lnh.Cc bc thc hin:

Cng vicc thc hintrc, sau mi kim traiu kin. Nuiu kin sai th thotkhi lnh do-while. Nu iu kin cn ng th thc hincng vicri quay li kim tra iu kintip.

dowhile(< Biu thc iu kin>);

Vng lp do-while (2)


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Vng lp do while (2)


output

Vng lp do-while (3)


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Vng lp do while (3)Nhp s nguyn n.Tnh tng cc snguyn t 1..n.

output

So snh cc vng lp


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So snh cc vng lp

Vng lp for/while:Kim tra iu kin trcthc hin cng vic sau.Cng vic c th khng c thc hin ln no.

Vng lp kt thc khi no iu kin sai.Vng lp do-while

Thc hin cng vic trckim tra iu kin sau.

Cng vic c thc hin t nht 1 ln.Vng lp kt thc khi no iu kin sai.

Cu lnh c bit


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Cu lnh c bit

Lnh breakDng thot khivng lp hoc switch-case.Tip tc thc hin lnh lin sau .

Lnh continueTrong vng lp, khi gp lnhcontinue, chng trnhs b qua cc cu lnh sau continue

for : quay ln tnh tr cho biu thc 3, ri kim tra iukin coi c lp tip khng.while/do-while: kim tra iu kin coi c lp tip khng.


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Ht chng


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LP TRNH CN BN

Phn 2 - Chng 5CHNG TRNH CONP.D.Nghip

Ni dung chng ny


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Ni dung chng ny

V dKhi nim v hm trong CXy dng mt hmTruyn tham s cho hmHm qui

V d(1)


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V d(1)In ra 50 k t * v 50 k t +

V d(2)


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V d(2)

u l u im ca vic dng hm?

Khi nim v hm trong C (1)


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v t o g C ( )

trnh rm r v mt thi gian khi vit chng trnh,nhng on chng trnh lp i lp li nhiu ln c vittrong 1 module.Chia chng trnh thnh nhiu module, mi module gii quy1 cng vic no .Mi module nh trn c gi l 1 chng trnh con.Cc module d dng c kim tra tnh ng n trc khic rp ni vo chng trnh.



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g ( )

V d: Tm s ln nht trong 3 s a, b, v c.



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g ( )

C 2 loi hm:Hm chunHm t nh ngha

Hm chun (hm th vin)


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( )c nh ngha sn bi ngn ng lp trnh v c cha vo cc thvin.Mun s dng phi khai bo#include Mt s th vin thng dng trong C:

stdio.h : Th vin cha cc hm vo/ ra chun (standardinput/output):

printf(), scanf(), getc(), putc(), gets(), puts(), fflush(), fopen(), fclose(),fread(), fwrite(), getchar(), putchar(), getw(), putw(), conio.h :Th vin cha cc hm vo ra trong ch DOS (DOS console):clrscr(), getch(), getche(), getpass(), cgets(), cputs(), putch(), clreol(), math.h: Th vin cha cc hm tnh ton:abs(), sqrt(), log(). log10(), sin(),cos(), tan(), acos(), asin(), atan(), pow(), exp(),

alloc.h: Th vin cha cc hm lin quan n vic qun l b nh:calloc(),realloc(), malloc(), free(), farmalloc(), farcalloc(), farfree(), io.h: Th vin cha cc hm vo ra cp thp:open(), _open(), read(), _read(),close(), _close(), creat(), _creat(), creatnew(), eof(), filelength(), lock(), graphics.h: Th vin cha cc hm lin quan n ha:initgraph(), line(),circle(), putpixel(), getpixel(), setcolor(),

Hm t nh ngha (hm ngidng) (1)


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g) ( )

Do ngi lp trnh t to ra nhm p ng nhu cu x l camnh.

Cu trc ca mt hm t thit k:

Hm t nh ngha (hm ngidng) (2)


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g) ( )

C php gi hm:([ Danh sch cc tham s ])V d:Tm UCLN ca 2 s t nhin:

Nguyn tc hot ng ca hm


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g y g

Trong chng trnh, khi gp mt li gi hm thcc bc sau c thc hin: Nu hm c tham s, trc tin cc tham s s c gn gi tr thc tng ng .Chng trnh s thc hin tip cc cu lnh trong thhm bt u t lnh u tin n cu lnh cui cng.Khi gp lnhreturnhoc du} cui cngtrong thnhm, chng trnh s thot khi hm tr v chntrnh gi n.Thc hin tip tc nhng cu lnh ca chng trnh.

Truyn tham s cho hm (1)


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y ( )

V d: Hon i ni dung ca 2 bin



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y ( )

Ta vn cha hon v c!Ti sao?

2 tham s a v b ca hoanvi ltham s hnh thcctruynbng gi tr (tham tr).

1 tham tr c coi nh 1 bin cc b ca hmcha d liu u vo cho hm.Cn 2 tham s a,b ca hoanvi trong li gi hm trong main() ltham s thc.

Khi chng trnh con c gi thi hnh,tham tr c cp nh v nhn gi tr l bn sao gi tr ca tham s thc.Do ,mi s thay i trn tham tr khng nh hng g ntham s thc tng ng.



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y ( )

Hy xem chng trnh sau



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y ( )

Ti sao ta hon v c?2 tham s a v b ca hoanvi ltham s hnh thc ctruyn bng a ch (tham bin) con tr.

Khi chng trnh con (ctc) c gi thi hnh,thambin cha a ch tham s thc, nh ca tham sthc c dng trc tip trong ctc qua bin con tr.Do ,mi s thay i trn tham bin u nh

hng n tham s thc tng ng.

Hm quy


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q y

Mt hm c gi l quy nu bn trong thnhm c lnh gi n chnh n.V d:

1 nu n=0

n*(n-1)! nu n#0n!=

unsigned int giaithua_dequy(int n)

{

if (n==0)

return 1;

elsereturn n*giaithua_dequy(n-1);

}

c im cn lu khi vit hm quy


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q y

Hm quy phi c 2 phn:

Phn dng: l trng hp nguyn t.

V d:n=0 trong tnh n!

Phn quy:l phn c gi li hm ang c nhngha.

V d:nu n>0 th n! = n * (n-1)!

u v khuyt im ca quy


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y q y

Lm chng trnh d c, d hiu v vn c nu bt rrng hn. quy tn b nh nhiu hn v tc thc hin chng trchm hn khng quy.

Ty tng bi c th m ta quyt nh c nn dng quy hakhng.C nhng trng hp khng dng quy th khng gii quyc bi ton.


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Ht chng

Ht chng


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LP TRNH CN BN

Phn 2 - Chng 6KIU MNGP.D.Nghip

Ni dung chng ny


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Gii thiu kiu mng trong CMng 1 chiuMng nhiu chiu

Gii thiu kiu mng trong C (1)


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V d:int a[10];

=> Hnh nh ca a trong b nh nh sau:



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Mng l mt tp hp cc phn t c nh c cng mt kiugi l kiu phn t.

Kiu phn tc th l c kiu bt k:k ts1 struct1 mng khc (=> mng ca mng hay mng nhiu chiu)

;



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V d: Lu tr 1 a gic trong ha:typedef struct {

int x;

int y;} Point;

typedef struct {Point Points[100];int nPoints;

} Polygon;

Points[1]

Points[2]

Points[3]

Points[0]



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Ta c th chia mng lm 2 loi:Mng 1 chiuMng nhiu chiu

Mng 1 chiu (1)


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Xt di gc ton hc, mng 1 chiu ging nh mt vectMi phn t ca mng 1 chiu c gi trkhng phi l mt mng khc. Khai bo mng vi s phn t xc nh

V d: float a[100];C php: ;

Khai bo mng vi s phn t khng xc nhV d: float a[];C php: ;


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Mng 1 chiu (3)


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V d: Gn gi tr ngay lc khai bo int primes[] = {2,3,5,7,11,13};

S tng ng vi:int primes[6];primes[0] = 2;primes[1] = 3;primes[2] = 5;

primes[3] = 7;primes[4] = 11;primes[5] = 13;

=>sizeof(primes)/sizeof(int)=6

Truy xut tng phn t ca mng (1)


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C php:Tn bin mng[Ch s]

Vd 1:int a[10];

a[0]=5; a[1]=5; a[2]=33; a[3]=33; a[4]=15;

printf(%d %d %d %d %d, a[0], a[1], a[2], a[3], a[4]);



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V d 2:Va khai bo va gn tr cho 1 mng 1 chiu cc snguyn. In mng s nguyn ny ln mn hnh.



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V d 3: i mt s nguyn dng thp phn thnh s nh phn.



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V d 4: Nhp vo mt dy n s v sp xp cc s theo th t tng.



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V d 5: Chng trnh sau s hin th kt qu g?

Cc phn t ca mng a[0], , a[11]. Vic truy cp a[12] svt rabn ngoi mng, nh ca bin b.

Sa li ny th no?

Mng nhiu chiu


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Mng nhiu chiu l mng c t2 chiu tr ln.iu c ngha lmi phn t ca mng l mt mng khc. Ngi ta thng s dng mng nhiu chiu lu cc matrn, cc ta 2 chiu, 3 chiu

Khai bo mng 2 chiu tng minh


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C php:

V d:

floatm[8][9]; // mng 2 chiu c 8*9 phn t l s thc

Khai bo mng 2 chiu khng tng minh


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khai bo mng 2 chiu khng tng minh, ta vn phi chra s phn t ca chiu th hai (chiu cui cng).

C php:

;V d:floatm[][9];

Cch khai bo ny cng c p dng trong trng hp:va khai bo va gn trmng 2 chiu l tham s hnh thc ca 1 hm.

Truy xut tng phn t ca mng 2 chiu


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Dng:Tn mng[Ch s 1][Ch s 2]

V d (1)


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Vit chng trnh cho php nhp 2 ma trn a, b c m dng n ct, thc hi php ton cng hai ma trn a,b v in ma trn kt qu ln mn hnh.

V d (2)


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Ht chng

Ht chng


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LP TRNH CN BN

Phn 2 - Chng 7KIU CON TRP.D.Nghip

Ni dung chng ny


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Gii thiu kiu d liu con trKhai bo v s dng bin con trCon tr v mngCon tr v tham s hnh thc ca hm

Gii thiu kiu d liu con tr(pointer) (1)


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1 con tr l 1 bin c dng cha a ch ca nhtrong b nh.Kch thc ca bin con tr lun l 2 byte.

V d 1:float a=3.145;float*ptr; //ptr is a pointer ptr=&a;

FFF2 3.145pointer ptr variable a

FFF2 (address)

Gii thiu kiu d liu con tr (2)


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V d 2: In Linux

Khai bo v s dng bin con tr


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Khai bo bin con tr Cc thao tc trn con tr

Khai bo bin con tr


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inta, b, *pa, *pb;//pa v pb s ch n bin intfloat f, *pf; //pa v pb s ch n bin floatvoid*ptr; //ptr s ch vo bt k bin kiu g

C php: *;

ngha: Khai bo mt bin c tn lTn con trdng

cha a ch ca cc bin c kiu Kiu.

Cc thao tc trn con tr


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Gn a ch ca bin cho bin con tr Ni dung ca nh con tr ch tiCp pht vng nh cho bin con trCp pht li vng nh cho bin con trGii phng vng nh cho bin con trMt s php ton trn con tr

Gn a ch ca bin cho bin con tr + Ni dung ca nh con tr ch ti (1)


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Dng & ly raa ch b nh (memory address)ca 1 bininta=6;int*c= &a; // &a l a ch b nh ca bin a

Dng * truy cp (access) nni dung (content)ca bin

m 1 con tr ang ch ninta=6;int*c= &a;*c=7; /*Thay i ni dung ca bin a bng cch

dng a ch ca n c cha trongcon tr c*/

tng ng via=7;



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Lu :

=> Error!V cho 1 con tr ch n 1 bin khc kiu vi n

Cp pht vng nh cho bin con tr(1)


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C 2 cch dng c bin con tr1. Cho n cha a ch ca 1 vng nh ang tn tiint a=6;int*c= &a; // &a l a ch b nh ca bin a

1. Cp pht 1 vng nh mi, ri cho con tr ch nint*ptr; ptr =(int*)malloc(sizeof(int));*ptr=6;

FFFA 6

pointer ptr

FFFA (address)

Cp pht vng nh cho bin con tr(2)


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void *malloc(size_t size): Cp pht vng nh c kch thc lsize (byte)void *calloc(size_t nitems, size_t size): Cp pht vng nh ckch thc l nitems*size (byte)

V d: inta, *pa, *pb; pa =(int*)malloc(sizeof(int)); /* Cp pht vng nh c kch thc

bng vi kch thc ca mt s nguyn */ pb= (int*)calloc(10, sizeof(int)); /* Cp pht vng nh c th chac 10 s nguyn*/

Cp pht li vng nh cho bin con tr


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int a, *pa; pa =(int*)malloc(sizeof(int)); /*Cp pht vng nh ckch thc 2 byte*/

pa = realloc(pa, 6); /*Cp pht li vng nh ckch thc mi l 6 byte*/

void *realloc(void *block, size_t size): ngha:

Cp pht li 1 vng nh do con trblock qun l, vng nh ny ckch thc mi l size; khi cp pht li th ni dung vng nh trc c copy n vng nh mi.Kt qu tr vca hm la ch u tin ca vng nh mi. a chny c th khc vi a ch c ch ra khi cp pht ban u. Kt ql NULL nu khng cp pht c.

Gii phng vng nh cho bin con tr


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void free(void *block): Gii phng vng nh c qun l bi con tr block

V dfree(pa);free(pb);=> gii phng vng nh do

2 bin con tr pa & pb ang ch n

Mt s php ton trn con tr


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Php gn =Php so snh == v !=Cng, tr con tr vi 1 s nguyn

Gn NULLcho 1 con tr

Php gn v php so snh


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V d: Hin ti ta c:int a=10, b=15;int *p, *q;float*f;p=&a; q=&b;

By gi th php so snh:(p!=q) => true(1)

Thc hin tip lnh gn:p=q;

By gi th:(p==q) => true(1)

Lnh f=p;=>Error, do khc kiuNhng lnh f=(float*)p; =>No error

FFF2 10p

FFF2 (address)

a

FFFA 15q

FFFA (address)

b

FFFA 10p

FFF2 (address)

a

FFFA 15q

FFFA (address)

b

Cng, tr con tr vi 1 snguyn


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Ta c th cng (+), tr (-) 1 con tr vi 1 s nguyn N no Kt qu tr v l 1 con tr. Con tr ny ch n vng nh cvng nh ca con tr hin ti N phn t.V d:Cho on chng trnh sau:

int*pa;int*pb, *pc; pa =(int*)malloc(20);/*Cp pht vng nh 20 byte=10 s nguyn*/ pb = pa + 7;

pc = pb - 3;Lc ny hnh nh ca pa, pb, pc nh sau:

Gn NULL cho 1 con tr


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V d:int x=25;int *ptr;ptr=&x;ptr=NULL;

Lnh gn ptr=NULL=> cho con tr ptr khngtr vo (khng cha a ch) vng nh no c

Con tr v mng (1)


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Mng v con tr c mi lin h vi nhauThay v truy cp 1 phn t mng bng ch s ca n, ta c th dng1 con tr

truy cp phn t th i, a[i]:y= *(pa+i);

Ch : pa+1 khng phi cng 1 vo pa. Thay vo , a ch lpa+sizeof(*pa)

Con tr v mng (2)


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1 mng c th c xem nh mt con tr. Con tr nyang ch n phn t u tin ca mng. Do :

1 mng c th c dng lmtham s cho 1 hm

Con tr v mng (3)


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x s c gi tr ca a[i] no, ti mi lnh gn sau?

Con tr v tham s hnh thc ca hm (1)


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V d 1:Vit 1 hm tng gi tr ca bin ln 1



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u l s khc nhau gia tham s a v b?



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V d 2:Vit hm hon i ni dung 2 bin



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V d 3:Vit li hm hon v nh sau:



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Ti sao hm trn c th hon v c?


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Ht chng

Ht chng


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LP TRNH CN BNPhn 2 - Chng 8

CHUI K TP.D.Nghip

Ni dung chng ny


216/290

Khi nimKhai boCc thao tc trn chui k t

Khi nim


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Chui k t l mt dy gm cc k t hoc mt mcc k t c kt thc bng k t \0 (k t NULLtrong bng m Ascii).Cc hng chui k t c t trong cp du nhkp .

Khai bo


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Khai bo theo mngKhai bo theo con trVa khai bo va gn gi tr

Khai bo theo mng


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C php: char [Chiu di ti a];V d: char Ten[12];

=> b nh s cung cp 12+1 bytes lu trni dung ca chui k t Ten; byte cui cng lu tr k t \0 chm dt chui

Ghi ch:Chiu di ti a ca bin chui: 1..255 bytes.Khng nn khai bo tha trnh lng ph b nh.

\0Ten:

Ten[0] Ten[12]

Khai bo theo con tr


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C php: char *;V d: char *Ten;Trong khai bo ny, b nh s dnh 2 byte lu tr a chca bin con tr Ten ang ch n.Cha cung cp ni lu tr d liu.Mun c ch lu tr d liu, ta phi gi n hmmalloc()hoccalloc()c trong alloc.h, sau mi gn d liu cho bin.

Tieu Dong Tu

Va khai bo va gn gi tr


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C php: char []=;V d:

Ghi ch: Chui c khai bo l mt mng cc k t nn cc thaotc trn mng c th p dng i vi chui k t.

Vua khai bao vua gan tr : Mau nang hay la mau mat em

Cc thao tc trn chui k t


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Nhp xut chui Nhp chui t bn phm Xut chui ln mn hnh

Mt s hm x l chui (trong string.h)

Nhp chui t bn phm


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Dng hmgets()C php:gets()

V d:

char Ten[20];gets(Ten);

Ta cng c th s dng hm scanf() nhp d liu cho bin

chui, tuy nhin lc ny ta ch c th nhp c mt chuikhng c du khong trng.Dng hm cgets() (trong conio.h)

Xut chui ln mn hnh


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xut mt chui (biu thc chui) ln mn hnh, ta s dng hm puts(C php: puts()V d:Nhp vo mt chui v hin th trn mn hnh chui va nhp:

Ngoi ra, ta c th s dng hm printf(), cputs() (trong conio.h) hin chui ln mn hnh.

Mt s hm x l chui (trong string.h)


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Cng chui - Hm strcat() Xc nh di chui - Hm strlen() i mt k t thng thnh k t hoa - Hmtoupper() i chui ch thng thnh chui ch hoa, hm strupr()

i chui ch hoa thnh chui ch thng, hm strlwr()Sao chp mt phn chui, hm strncpy() Trch mt phn chui, hm strchr()Tm kim ni dung chui, hm strstr()

So snh chui, hm strcmp()So snh chui, hm stricmp() Khi to chui, hmmemset() i t chui ra s, hmatoi(), atof(), atol()(trong stdlib.h)

Cng chui - strcat()(1)


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C php:char *strcat(char *des, const char *source)

Hm ny c tc dng ghp chui ngun (source) vo chuich (des).Tr v con tr ch n chui kt qu.

Cng chui - strcat()(2)


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V d: Nhp vo h lt v tn ca mt ngi, sau in c h v tn ca h ln mn hnh.

Xc nh di chui - strlen()


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C php: int strlen( const char * s)V d: Xc nh di 1 chui nhp t bn phm

i mt k t thng thnh k t hoa - toupper()


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C php:char toupper(char c)

Hm ny (trong ctype.h) c dng chuyni 1 k t thng thnh k t hoa.

i chui ch thng thnh chui ch hoa - strupr()(1)


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C php:char *strupr(char *s)

Hm ny c dng chuyn i chui ch thng thnhchui ch hoa.Kt qu tr v l 1 con tr ch n chui kt qu.

i chui ch thng thnh chui ch hoa - strupr()(2)


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V d: Nhp vo mt chui k t t bn phm. Sau s dnhm strupr() chuyn i chng thnh chui ch hoa.

i chui ch hoa thnh chui ch thng - strlwr()


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C php:char *strlwr(char *s)

Hm ny c dng chuyn i chui ch hoa thnh chuch thng.Kt qu tr v l 1 con tr ch n chui kt qu.

Sao chp chui - strcpy()(1)


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C php:char *strcpy(char *Des,const char*Source)

Hm ny c dng sao chp ton b ni dung ca chungun vo chui ch.

Sao chp chui - strcpy()(2)


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V d: Vit chng trnh cho php chp ton b chui ngunvo chui ch

Sao chp mt phn chui - strncpy()v Trch mt phn chui - strchr()


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Sao chp mt phn chuiC php: char *strncpy(char *Des, const char *Source, size_t n)Chp n k t u tin ca chui ngun sang chui ch.

Trch mt phn chui, hm strchr()C php : char *strchr(const char *str, int c)Trch ra chui con ca str bt u t k t c cho n ht chui.

Ghi ch: Nu k t c khng c trong chui, kt qu tr v l NULL.Kt qu tr v ca hm l mt con tr, con tr ny ch n k t cu tin trong chui str.

Tm kim ni dung chui - strstr() (1)


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C php:char *strstr(const char *s1, const char *s2)

Hm ny c dng tm kim s xut hin utin ca chui s2 trong chui s1.Kt qu tr l 1 con tr ch n phn t u tin cachui s1 c cha chui s2 hoc gi tr NULL nuchui s2 khng c trong chui s1.

Tm kim ni dung chui - strstr() (2)


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V d: Vit chng trnh s dng hm strstr() ly ra mt phn ca chui gc bt u t chui hoc.

So snh chui - strcmp()(1)


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C php:int strcmp( const char *s1, const char *s2)

So snh 2 chui s1 v s2 vi nhau.

Kt qu tr v l 1 s int:0 nu s1 > s2

Tng t:int stricmp(const char *s1, const char *s2)So snh khng phn bit k t hoa/thng

So snh chui - strcmp()(2)


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V d:#include

#include

#inlude

void main(){char s1[10]=Chao, s2[10]=chao;

printf(%d,strcmp(s1,s2));

getch();

}

-32

#include

#include

#inlude

voidmain(){char s1[10]=chao, s2[10]=chao;

printf(%d,strcmp(s1,s2));

getch();

}0

Khi to chui - memset()


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C php: void*memset(char *Des, int c, size_t n) t n k t u tin ca chui Des l k t c.Gi tr tr v: chui Des. Nm trong th vin: string.h v mem.h

i t chui ra s - atoi(), atof(),atol() (trong stdlib.h)


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C php :intatoi(const char *s) : chuyn chui thnh s nguynlongatol(const char *s) : chuyn chui thnh s nguyn difloatatof(const char *s) : chuyn chui thnh s thc Nu chuyn i khng thnh cng, kt qu tr vca cc hm l 0.V d:atoi(1234)=> 1234


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Ht chng


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LP TRNH CN BNPhn 2 - Chng 9KIU CU TRC

P.D.Nghip

Ni dung chng ny


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Kiu cu trc trong CCc thao tc trn bin kiu cu trcCon tr v cu trc

Kiu cu trc trong C


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Khi nim nh ngha kiu cu trcKhai bo bin cu trc

Khi nim


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Kiu cu trc (struct) l kiu d liu baogm nhiu thnh phn c kiu khc nhau, mi thnh phn c gi l mttrng (field) N khc vi kiu mng (ni m cc phn t c cng kiu)

V d:

1 struct:

1 mng:

nh ngha kiu cu trc +Khai bo bin cu trc (1)


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Cch 1:struc t SinhVien{

char MSSV[10];char HoTen[40];struct NgayThang

NgaySinh;int Phai;char DiaChi[40];

};

Khaibo bin:struct NgayThang NgaySinh;struct SinhVien SV;

struct {;;

..;} [bin 1, bin 2];

V d:struct NgayThang{unsigned char Ngay;

unsigned char Thang;unsigned int Nam;

};

struct tn_bin;



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Ch :struct khng tn:

Tuy nhin

A v B l cc structc 2 thnhphn x v y.

struct ny khng c tn, nn ngoiA v B, ta khng th nh nghathm cc bin khc c.

A v B l cc bin c kiustruct point.

Sau ny ta c th khai bo thmcc bin khc c kiustruct point ny.



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Cch 2:typedef struct {

char MSSV[10];char HoTen[40];NgayThang NgaySinh;

int Phai;char DiaChi[40];} SinhVien;

Khai bo bin:

NgayThang NgaySinh;SinhVien SV;

typedef struct{ ; ;

.. ;} ;

V d:typedef struct {unsigned char Ngay;

unsigned char Thang;unsigned int Nam;

} NgayThang; tn_bin;

Cc thao tc trn bin kiu cutrc


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Truy xut n tng trng ca bin cu trcKhi to cu trc

Truy xut n tng trng (field)ca bin cu trc (1)


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C php: .

V d 1:Chng trnh cho php c d liu t bn phm cho bin mu tin SinhVien v in bin mu tin ln mn hnh:



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Kt qu ca 1 ln nhp:



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Lu :Cc bin cu trc c th gn cho nhauV d:

s=SV; // gn ly gi tr ton b cu trc

Ta khng th thc hin c cc thao tc sau y cho bincu trc:

S dng cc hm xut nhp trn bin cu trcCc php ton quan h, cc php ton s hc v logic

Khi to cu trc

h kh b


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Bin cu trc c th c khi to gi tr banu lc khai bo

V d:struct NgayThang NgaySinh ={29, 8, 1986};

Con tr v cu trc

Kh i b


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Khai boS dng cc con tr kiu cu trcTruy cp cc thnh phn ca cu trc ang c

qun l bi con tr

Khai bo (1)

C h


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C php:struct * ;

V d 1:struct NgayThang *p;

hoc NgayThang *p; // Nu c dng typedef

Khai bo (2)

V d 2


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V d 2:

Truy cp n cc trng:

Nu dng con tr th:

S dng cc con tr kiu cu trc

C 2 h


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C 2 cch:Phi cp pht b nh cho nCho n ch vo (cha a ch) bin ang tn ti

V d:struct NgayThang *p;p=( struct NgayThang *) malloc (sizeof( struct NgayThang));p->Ngay=29; p->Thang=8; p->Nam=1986;

Hoc struct NgayThang Ngay = {29,8,1986};p = &Ngay;

Truy cp cc thnh phn ca cu trcang c qun l bi con tr (1)

Vi kh i b


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Vi khai bo sau:struct NgayThang *p;

Ta c th truy cp n cc trng ca n nh sau:

p->Ngay p->Thanghoc

(*p).Ngay (*p).Thang

Truy cp cc thnh phn ca cu trcang c qun l bi con tr (3)

V d


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V d


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Ht chng

C


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LP TRNH CN BNPhn 2 - Chng 10

KIU TP TINP.D.Nghip

Ni dung chng ny

Mt khi i t ti


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Mt s khi nim v tp tinCc thao tc trn tp tinTruy cp tp tin vn bn

Truy cp tp tin nh phn

Mt s khi nim v tp tin (file) (1)

T i t ki t ti ?


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Ti sao ta cn n kiu tp tin?Cho php lu tr d liu b nh ngoi (a).Khi kt thc chng trnh th d liu vn cn do

chng ta c th s dng nhiu ln.Kch thc ln d liu khng hn ch.

Mt s khi nim v tp tin (file) (2)C 3 loi d liu kiu tp tin:

T ti b (T t Fil )


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Tp tin vn bn (Text File)Dng ghi cc k t ln a (di dng m Ascii)C cha:K hiu \n : xung dng

K t EOF (End Of File) c m Ascii l 26: nm cui tp tinTp tin nh kiu (Typed File)

Gm nhiu phn t c cng kiu: char, int, long, struct c lu tr trn a di dng mt chui cc byte lin tc.

Tp tin khng nh kiu (Untyped File)Gm cc cu trc d liu m ta khng quan tm n ni dunghoc kiu ca n.Ta ch lu n cc yu t vt l ca tp tin nh ln, ...

Mt s khi nim v tp tin (file)(3)

Bin tp tind d h


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Bin tp tinc dng i din cho mt tp tinCc thao tc ln tp tin s c thc hin thng qua bin ny

Con tr tp tin

Ti mi thi im, s c mt v tr ca tp tin m ti vicc/ghi thng tin s xy raTa hnh dung c 1 con tr ang ch n v tr Sau khi c/ghi xong d liu, con tr s chuyn dch thm mt phn t v pha cui tp tin.Sau phn t d liu cui cng ca tp tin l du kt thc tp tinEOF

Cc thao tc trn tp tin

Khai bo bin tp tin


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Khai bo bin tp tinM tp tinng tp tin

Kim tra n cui tp tin hay cha?Di chuyn con tr tp tin v u tp tin - Hmrewind()

Khai bo bin tp tin

C php :


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C php :FILE ;Cc bin trong danh sch phi l cc con tr v

c phn cch bi du phy(,).V d: FILE*f1,*f2;

M tp tin (1)

C php :


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C php :FILE*fopen(char *Path, const char *Mode) ngha:

Tr v con tr tp tin ca tp tin c mTr vNULLnu c li

M tp tin (2)Path: chui ch ng dn n tp tin trn aT h i h h h i C i


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Type: chui xc nh cch thc m tp tin s m. Cc gi trc th caMode:

M tp tin (3)

V d: M mt tp tin tn TEST txt ghiFILE*f


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V d: M mt tp tin tn TEST.txt ghi.FILE*f;f = fopen(TEST.txt, w);if (f!=NULL){

// Cc cu lnh thao tc vi tp tin// ng tp tin}

=> m tp tin ghi

=> nu tp tin tn ti ri th tp tin s b xa v mt tp tin mi c to ra

ng tp tin

C php : int fclose(FILE *f)Ghi d li l i i l i


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C php : int fclose(FILE *f)Ghi d liu cn li trong vng m vo tp tin v ng li tp tf l con tr tp tin c m bi hmfopen()Gi tr tr v l 0 bo rng vic ng tp tin thnh cng

Gi tr tr v lEOFnu c xut hin li

C php : int fcloseall()ng tt c cc tp tin li

Tr v tng s cc tp tin c ng li Nu khng thnh cng, kt qu tr v l EOF


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Di chuyn con tr tp tin v utp tin - Hm rewind()

C php: id i d(FILE *f)


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C php: voidrewind(FILE *f)

ngha:Lm cho con tr quay v u tp tin nh khi m n

Truy cp tp tin vn bn

Ghi d liu ln tp tin vn bn


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Ghi d liu ln tp tin vn bnc d liu t tp tin vn bn

Ghi d liu ln tp tin vn bn (1)

Hm putc()


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Hm putc()int putc(int c, FILE *f)

c dng ghi mt k t ln mt tp tin vn bnang c m (lin kt vi con tr f) lm vicc cha mAsciica k tHm ny tr vEOFnu gp li


Hm fputs()


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Hm fputs()int fputs(const char *buffer,FILE*f)

c dng ghi mt chui k t cha trong vngm ln tp tin vn bnHm ny tr v gi tr0 nu buffer cha chui rng vtr vEOFnu gp li

Ghi d liu ln tp tin vn bn (3)V d:Vit chng trnh ghi chui k t ln tp tin vn bnD:\\Baihat txt


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D:\\Baihat.txt


Hm fprintf()


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Hm fprintf()fprintf(FILE*f,const char *format, varexpr)

c dng ghi d liu c nh dng ln tp tin vn bnformat: chui nh dng (ging vi cc nh dng ca hm printf())varexpr: danh sch cc biu thc, mi biu thc cch nhaudu phy (,)

c d liu t tp tin vn bn(1)

Hm getc() f


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Hm getc()int getc(FILE *f)

c dng c d liu t tp tin vn bn ang c m lm vic (lin kt vi f)Hm ny tr v m Ascii ca mt k t c c (k cEOF)

c d liu t tp tin vn bn(2)Hm fgets()

char*fgets(char*buffer intn FILE*f)


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char fgets(char buffer,intn, FILE f)

c dng c 1 chui k t t tp tin vn bn ang c m(lin kt vi con tr f)c cho n khi n k t hoc gp k t xung dng \n (kt ny cng c a vo chui kt qu) hay gp k t kt thcEOF (k t ny khng c a vo chui kt qu) buffer: ch n cng nh ln cha cc k t nhn cK t NULL (\0) t ng c thm vo cui chui kt qu ltrong vng mHm tr v a ch u tin ca vng m khi khng gp li vcha gp k t kt thc EOF. Ngc li, hm tr v gi tr NUL

c d liu t tp tin vn bn(3)

Hm fscanf()f f( f h f li )


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Hm fscanf()fscanf(FILE*f,const char *format, varlist)

c dng c d liu t tp tin vn bn vo danhsch cc bin theo nh dng.format: chui nh dng (ging hm scanf())varlist: danh sch cc bin mi bin cch nhau du phy (,).

c d liu t tp tin vn bn(4)V d:Vit chng trnh chp tp tinD:\Baihat.txt trn sangtp tinD:\Baica.txt.


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tp tinD:\Baica.txt.

Truy cp tp tin nh phn

Ghi d liu ln tp tin nh phn d li i h h


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Ghi d liu ln tp tin nh phnc d liu t tp tin nh phnDi chuyn con tr tp tin

V d

Ghi d liu ln tp tin nh phn

Hm fwrite()si e t f rite(const oid*ptr si e t si e si e t nFILE*f)


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Hm fwrite() size_t fwrite(const void*ptr, size_t size, size_t n,FILE*f)

ptr : con tr ch n vng nh cha thng tin cn ghi ln ttin.n: s phn t s ghi ln tp tin.size: kch thc ca mi phn t.f : con tr tp tin c m.Gi tr tr v ca hm ny l s phn t c ghi ln tp tGi tr ny bng n tr khi xut hin li.

c d liu t tp tin nh phn

Hm fread()size t fread(const void*ptr size t size size t nFILE*f)


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Hm fread()size_t fread(const void*ptr, size_t size, size_t n,FILE*f)

ptr: con tr ch n vng nh s nhn d liu t tp ti

n: s phn t c c t tp tinsize: kch thc ca mi phn tf: con tr tp tin c m Gi tr tr v ca hm ny l s phn t c c tp tin. Gi tr ny bng n hay nh hn n nu chn cui tp tin hoc c li xut hin

Di chuyn con tr tp tinHm fseek()

int fseek(FILE*f long offset int whence)


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int fseek(FILE*f,long offset, int whence)c dng di chuyn con tr tp tin n v tr ch nhf: con tr tp tin ang thao tcoffset: s byte cn dch chuyn con tr tp tin k t v tr trc . Pht u tin l v tr 0.whence: v tr bt u tnh offset, ta c th chn im xut pht l

Kt qu tr v ca hm l 0 nu vic di chuyn thnh cng. Nu khthnh cng, 1 gi tr khc 0 ( l 1 m li) c tr v.

V dVit chng trnh ghi ln tp tin CacSo.Dat 3 gi tr s (thcnguyn, nguyn di). Sau c cc s t tp tin va ghi v


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g y , g y ) p ghin th ln mn hnh

Ht chng


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Ht chng

lap trinh can ban

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