C语言函数大全
更新时间：2017/2/22 18:37:00 浏览量：582 手机版
A
函数名: abort
功 能: 异常终止一个进程
用 法: void abort(void);
程序例:
#include
#include
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
#include
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、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
#include
#include
#include
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=0; i<80; i++)
{ ch_out = buf[strt+i];
putchar(ch_out);
}
printf("\n");
return(0);
}
函数名: access
功 能: 确定文件的访问权限
用 法: int access(const char *filename, int amode);
程序例:
#include
#include
int file_exists(char *filename);
int main(void)
{ printf("Does exist: %s\n",
file_exists("") ? "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
#include
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;
}
函数名: allocmem
功 能: 分配DOS存储段
用 法: int allocmem(unsigned size, unsigned *seg);
程序例:
#include
#include
#include
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
#include
#include
#include
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 */
}