|
Turbo C 2.0、Borland C++库函数及用例(9) }int main(void)
{
if (lookup(512))
printf("512 is in the table.\n");
else
printf("512 isn't in the table.\n"); return 0;
}字母Ｃ开头函数
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;
/* There's 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 plus the NULL terminator */
buffer[0] = 6; 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);
|
