C语言函数大全 c.doc
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C语言函数大全 c
C语言函数大全 c
返回C语言函数大全
函数名: cabs
功 能: 计算复数的绝对值
用 法: double cabs(struct complex z);
程序例:
#include stdio.h
#include math.h
int main(void)
{
struct complex z;
double val;
z.x = 2.0;
z.y = 1.0;
val = cabs(z);
printf(The absolute value of %.2lfi %.2lfj is %.2lf, z.x, z.y, val);
return 0;
}
函数名: calloc
功 能: 分配主存储器
用 法: void *calloc(size_t nelem, size_t elsize);
程序例:
#include stdio.h
#include alloc.h
int main(void)
{
char *str = NULL;
/* allocate memory for string */
str = calloc(10, sizeof(char));
/* copy Hello into string */
strcpy(str, Hello);
/* display string */
printf(String is %s\n, str);
/* free memory */
free(str);
return 0;
}
函数名: ceil
功 能: 向上舍入
用 法: double ceil(double x);
程序例:
#include math.h
#include stdio.h
int main(void)
{
double number = 123.54;
double down, up;
down = floor(number);
up = ceil(number);
printf(original number %5.2lf\n, number);
printf(number rounded down %5.2lf\n, down);
printf(number rounded up %5.2lf\n, up);
return 0;
}
函数名: cgets
功 能: 从控制台读字符串
用 法: char *cgets(char *str);
程序例:
#include stdio.h
#include conio.h
int main(void)
{
char buffer[83];
char *p;
/* Theres space for 80 characters plus the NULL terminator */
buffer[0] = 81;
printf(Input some chars:);
p = cgets(buffer);
printf(\ncgets read %d characters: \%s\\n, buffer[1], p);
printf(The returned pointer is %p, buffer[0] is at %p\n, p, buffer);
/* Leave room for 5 characters pl
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