1. C baa

2.

C 1999 (C99)

• 1970

• AT&T Bell Laboratoies

:

3.

-

• main

• int main(){} int main(void){} int main(int argc, char *argv[]){}

4.

*.c

int i=0; int main(){ printf(i=%d,i); return 0; }

5.

• *.c

• int func1(){ /*- */

• *.h

• int func1();

6.

src1.c void func1(){ printf(Hello, world); }

src1.h void func1();

src2.c

• , src1.c #include src1.h ... func1(); ...

7.

• • /* */

• • /* */

• • //

• • // //

8.

, ,

• a-z, A-Z

• _

• 0-9

31

64

9.

• int i=0; void func(){}

• {int i=0; }

• void func(int i, int j);

• void func(){ int i; }

10.

int i=1; // int main(){ char i=5; // i == 5 ... ... { ... short i=0; // i==0 ... } ... // i == 5 }

11.

• char

• • unsigned char 1 0 ..255

• • signed char 1 - -128 ... 127

• int - 2/4

• • -32,768 -2,147,483,648

• • 32,767 2,147,483,647

• unsigned int - 2/4

• • 0

• • 65,535 or 2,147,483,647

• short - 2 - -32,768 .. 32,767

• unsigned short 2 0 .. 65,535

12.

long - 4 - -2,147,483,648 ..2,147,483,647

unsigned long 4 0 .. 4,294,967,295

long long(C99) 8

• -9,223,372,036, 854,775,808

• 9,223,372,036, 854,775,807

unsigned long long (C99) 8

• 0

• 18,446,744,073, 709,551,615

• size_t sizeof(type)

13.

float -4

• 3.4E+38

• 1.2E-38

• : 6

double - 8

• 1.7E+308

• 2.3E-308

• : 15

long double - 10

• 1.1E+4932

• 3.4E-4932

• :19

14.

enum [] { };

• enum list1 { value1, value2, value3 }

, 0

• enum list2 { value1, value2=4, value5, value6=4 }

15. void

, , void

• void func{}

: void *

• ,

• void * func(){ char buf[]={1,0,0,0}; return buf; } int *i=(int *)func(); // *i==1;

16.

• int

• • 0x200, 010

• unsigned int

• • 512U

• long

• • 0L

• unsigned long

• • 0Xf0fUL

• long long

• • 0777LL

• unsigned long long

• • 0xAAAllu

17.

• 10.0 10

• 2.34E5 2.34 x 10 5

• 67e-12 67.0 x 10 -12

float float_val = 10.5f;

long double ld_val=0.16l

18.

• 'a'

• 'x61'

• :

• • ,, , o, x, u

• Hello, world!

• Hello, orld!

• Hello, world!

19.

• int i=10; long l=i;

• long l=10; int i=(int)l;

• • char buf[]={1,0,0,0}; int *i=(int *)buf; printf(: %d,*i);

20.

[ ]( ).->++-- (type name){list}( -> )

++-- !~+-*&sizeof( )

> ( -> )

< >= ( -> )

== != ( -> )

& ( -> )

^ ( -> )

| ( ->)

&& ( -> )

|| ( -> )

? : (