求C语言函数大全

功 能: 异常终止一个进程

用 法: void abort(void)

程序例:

#include <stdio.h>

#include <stdlib.h>

int main(void)

{

printf("Calling abort()\n")

abort()

return 0/* This is never reached */

}

函数名: abs

功 能: 求整数的绝对值

用 法: int abs(int i)

程序例:

#include <stdio.h>

#include <math.h>

int main(void)

{

int number = -1234

printf("number: %d absolute value: %d\n", number, abs(number))

return 0

}

函数名: absread, abswirte

功 能: 绝对磁盘扇区读运册答、写数据

用 法: int absread(int drive, int nsects, int sectno, void *buffer)

int abswrite(int drive, int nsects, in tsectno, void *buffer)

程序例:

/* absread example */

#include <stdio.h>

#include <conio.h>

#include <process.h>

#include <dos.h>

int main(void)

{

int i, strt, ch_out, sector

char buf[512]

printf("Insert a diskette into drive A and press any key\n")

getch()

sector = 0

if (absread(0, 1, sector, &buf) != 0)

{

perror("Disk problem")

exit(1)

}

printf("Read OK\n")

strt = 3

for (i=0i<80i++)

{

ch_out = buf[strt+i]

putchar(ch_out)

}

printf("\n")

return(0)

}

函数名: access

功 能: 确定文姿销件的访问权限

用 法: int access(const char *filename, int amode)

程序例:

#include <stdio.h>

#include <io.h>

int file_exists(char *filename)

int main(void)

{

printf("Does NOTEXIST.FIL exist: %s\n",

file_exists("NOTEXISTS.FIL") ? "YES" : "NO")

return 0

}

int file_exists(char *filename)

{

return (access(filename, 0) == 0)

}

函数名: acos

功 能: 反余弦函数

用 法: double acos(double x)

程序例:

#include <stdio.h>

#include <math.h>

int main(void)

{

double result

double x = 0.5

result = acos(x)

printf("The arc cosine of %lf is %lf\n", x, result)

return 0

}

函数旁慧名: allocmem

功 能: 分配DOS存储段

用 法: int allocmem(unsigned size, unsigned *seg)

程序例:

#include <dos.h>

#include <alloc.h>

#include <stdio.h>

int main(void)

{

unsigned int size, segp

int stat

size = 64/* (64 x 16) = 1024 bytes */

stat = allocmem(size, &segp)

if (stat == -1)

printf("Allocated memory at segment: %x\n", segp)

else

printf("Failed: maximum number of paragraphs available is %u\n",

stat)

return 0

}

函数名: arc

功 能: 画一弧线

用 法: void far arc(int x, int y, int stangle, int endangle, int radius)

程序例:

#include <graphics.h>

#include <stdlib.h>

#include <stdio.h>

#include <conio.h>

int main(void)

{

/* request auto detection */

int gdriver = DETECT, gmode, errorcode

int midx, midy

int stangle = 45, endangle = 135

int radius = 100

/* initialize graphics and local variables */

initgraph(&gdriver, &gmode, "")

/* read result of initialization */

errorcode = graphresult() /* an error occurred */

if (errorcode != grOk)

{

printf("Graphics error: %s\n", grapherrormsg(errorcode))

printf("Press any key to halt:")

getch()

exit(1) /* terminate with an error code */

}

midx = getmaxx() / 2

midy = getmaxy() / 2

setcolor(getmaxcolor())

/* draw arc */

arc(midx, midy, stangle, endangle, radius)

/* clean up */

getch()

closegraph()

return 0

}

函数名: asctime

功 能: 转换日期和时间为ASCII码

用 法: char *asctime(const struct tm *tblock)

程序例:

#include <stdio.h>

#include <string.h>

#include <time.h>

int main(void)

{

struct tm t

char str[80]

/* sample loading of tm structure */

t.tm_sec= 1 /* Seconds */

t.tm_min= 30/* Minutes */

t.tm_hour = 9 /* Hour */

t.tm_mday = 22/* Day of the Month */

t.tm_mon= 11/* Month */

t.tm_year = 56/* Year - does not include century */

t.tm_wday = 4 /* Day of the week */

t.tm_yday = 0 /* Does not show in asctime */

t.tm_isdst = 0 /* Is Daylight SavTimedoes not show in asctime */

/* converts structure to null terminated

string */

strcpy(str, asctime(&t))

printf("%s\n", str)

return 0

}

函数名: asin

功 能: 反正弦函数

用 法: double asin(double x)

程序例:

#include <stdio.h>

#include <math.h>

int main(void)

{

double result

double x = 0.5

result = asin(x)

printf("The arc sin of %lf is %lf\n", x, result)

return(0)

}

函数名: assert

功 能: 测试一个条件并可能使程序终止

用 法: void assert(int test)

程序例:

#include <assert.h>

#include <stdio.h>

#include <stdlib.h>

struct ITEM {

int key

int value

}

/* add item to list, make sure list is not null */

void additem(struct ITEM *itemptr) {

assert(itemptr != NULL)

/* add item to list */

}

int main(void)

{

additem(NULL)

return 0

}

函数名: atan

功 能: 反正切函数

用 法: double atan(double x)

程序例:

#include <stdio.h>

#include <math.h>

int main(void)

{

double result

double x = 0.5

result = atan(x)

printf("The arc tangent of %lf is %lf\n", x, result)

return(0)

}

函数名: atan2

功 能: 计算Y/X的反正切值

用 法: double atan2(double y, double x)

程序例:

#include <stdio.h>

#include <math.h>

int main(void)

{

double result

double x = 90.0, y = 45.0

result = atan2(y, x)

printf("The arc tangent ratio of %lf is %lf\n", (y / x), result)

return 0

}

函数名: atexit

功 能: 注册终止函数

用 法: int atexit(atexit_t func)

程序例:

#include <stdio.h>

#include <stdlib.h>

void exit_fn1(void)

{

printf("Exit function #1 called\n")

}

void exit_fn2(void)

{

printf("Exit function #2 called\n")

}

int main(void)

{

/* post exit function #1 */

atexit(exit_fn1)

/* post exit function #2 */

atexit(exit_fn2)

return 0

}

函数名: atof

功 能: 把字符串转换成浮点数

用 法: double atof(const char *nptr)

程序例:

#include <stdlib.h>

#include <stdio.h>

int main(void)

{

float f

char *str = "12345.67"

f = atof(str)

printf("string = %s float = %f\n", str, f)

return 0

}

函数名: atoi

功 能: 把字符串转换成长整型数

用 法: int atoi(const char *nptr)

程序例:

#include <stdlib.h>

#include <stdio.h>

int main(void)

{

int n

char *str = "12345.67"

n = atoi(str)

printf("string = %s integer = %d\n", str, n)

return 0

}

函数名: atol

功 能: 把字符串转换成长整型数

用 法: long atol(const char *nptr)

程序例:

#include <stdlib.h>

#include <stdio.h>

int main(void)

{

long l

char *str = "98765432"

l = atol(lstr)

printf("string = %s integer = %ld\n", str, l)

return(0)

}

就是函数的名字，只要符合命名规范的链核名字都可以棚物掘作为函数名

例如

int

fun()

{

}

那么蚂尘这个函数的名字就是

fun

int

fun2()

{

}

那么这个函数的名字就是

fun2