Gio trnh C++ Full ting vit.docx

Ti Full trn b Lp trnh C++, C# ti y

Bi 1 : Cu Trc Ca Mt Chng Trnh C++

C l mt trong nhng cch tt nht bt u hc mt ngn ng lp trnh l bng mt chng trnh. Vy y l chng trnh u tin ca chng ta :

// my first program in C++

#include

int main ()

{

cout >=, = 6)

s tr gi tr true

tt nhin thay v s dng cc s, chng ta c th s dng bt c biu thc no. Cho a=2, b=3 v c=6

(a*b >= c)

s tr gi tr true.

(b+4 < a*c)

s tr gi tr false

Cn ch rng = (mt du bng) lf hon ton khc vi == (hai du bng). Du u tin l mt ton t gn ( gn gi tr ca biu thc bn phi cho bin bn tri) v du cn li (==) l mt ton t quan h nhm so snh xem hai biu thc c bng nhau hay khng.

Trong nhiu trnh dch c trc chun ANSI-C++ cng nh trong ngn ng C, cc ton t quan h khng tr v gi tr logic true hoc false m tr v gi tr int vi 0 tng ng vi false cn gi tr khc 0 (thng l 1) th tng ng vi true.

Cc ton t logic ( !, &&, || ).

Ton t ! tng ng vi ton t logic NOT, n ch c mt i s pha bn phi v vic duy nht m n lm l i ngc gi tr ca i s t true sang false hoc ngc li. V d:

!(5 == 5)

tr v false v biu thc bn phi (5 == 5) c gi trtrue.

!(6 6)) tr v true ( true || false ).

Ton t iu kin ( ? ).

Ton t iu kin tnh ton mt biu thc v tr v mt gi tr khc tu thuc vo biu thc l ng hay sai. Cu trc ca n nh sau:

condition ? result1 : result2

Nu condition l true th gi tr tr v s l result1, nu khng gi tr tr v l result2.

7==5 ? 4 : 3

tr v 3 v 7 khng bng 5.

7==5+2 ? 4 : 3

tr v 4 v 7 bng 5+2.

5>3 ? a : b

tr v a, v 5 ln hn 3.

a>b ? a : b

tr v gi tr ln hn, a hoc b.

Cc ton t thao tc bit ( &, |, ^, ~, ).

Cc ton t thao tc bit thay i cc bit biu din mt bin, c ngha l thay i biu din nh phn ca chng

ton t

asm

M t

&

AND

Logical AND

|

OR

Logical OR

^

XOR

Logical exclusive OR

~

NOT

o ngc bit

SHR

Dch bit sang phi

Cc ton t chuyn i kiu

Cc ton t chuyn i kiu cho php bn chuyn i d liu t kiu ny sang kiu khc. C vi cch lm vic ny trong C++, cch c bn nht c tha k t ngn ng C l t trc biu thc cn chuyn i tn kiu d liu c bc trong cp ngoc n (), v d:

int i;float f = 3.14;i = (int) f;

on m trn chuyn s thp phn 3.14 sang mt s nguyn (3). y, ton t chuyn i kiu l (int). Mt cch khc lm iu ny trong C++ l s dng cc constructors ( mt s sch thut ng ny c dch l cu t nhng ti thy n c v khng xui tai lm) thay v dng cc ton t : t trc biu thc cn chuyn i kiutn kiu mi v bao bc biu thc gia mt cp ngoc n.

i = int ( f );

C hai cch chuyn i kiu u hp l trong C++. Thm vo ANSI-C++ cn c nhng ton t chuyn i kiu mi c trng cho lp trnh hng i tng.

sizeof()

Ton t ny c mt tham s, c th l mt kiu d liu hay l mt bin v tr v kch c bng byte ca kiu hay i tng .

a = sizeof (char);

a s mang gi tr 1 v kiu char lun c kch c 1 byte trn mi h thng. Gi tr tr v ca sizeof l mt hng s v vy n lun lun c tnh trc khi chng trnh thc hin.

Cc ton t khc

Trong C++ cn c mt s cc ton t khc, nh cc ton t lin quan n con tr hay lp trnh hng i tng. Chng s c ni n c th trong cc phn tng ng.

Th t u tin ca cc ton t

Khi vit cc biu thc phc tp vi nhiu ton hng cc bn c th t hi ton hng no c tnh trc, ton hng no c tnh sau. V d nh trong biu thc sau:

a = 5 + 7 % 2

c th c hai cch hiu sau:

a = 5 + (7 % 2) vi kt qu l 6, hoca = (5 + 7) % 2 vi kt qu l 0

Cu tr li ng l biu thc u tin. V nguyn nhn ni trn, ngn ng C++ thit lp mt th t u tin gia cc ton t, khng ch ring cc ton t s hc m tt c cc ton t c th xut hin trong C++. Th t u tin ca chng c lit k trong bng sau theo th t t cao xung thp.

Th t

Ton t

M t

Associativity

1

::

scope

Tri

2

() [ ] -> . sizeof

Tri

3

++ --

tng/gim

Phi

~

o ngc bit

!

NOT

& *

Ton t con tr

(type)

Chuyn i kiu

+ -

Dng hoc m

4

* / %

Ton t s hc

Tri

5

+ -

Ton t s hc

Tri

6

>

Dch bit

Tri

7

< >=

Ton t quan h

Tri

8

== !=

Ton t quan h

Tri

9

& ^ |

Ton t thao tc bit

Tri

10

&& ||

Ton t logic

Tri

11

?:

Ton t iu kin

Phi

12

= += -= *= /= %=>>=