Header File 

math.h  

Category 

Math Routines 

Prototype 

double ceil(double x); 

long double ceill(long double x); 

Description 

Rounds up. 

ceil finds the smallest integer not less than x.  

ceill is the long double version; it takes a long double argument and returns a long double result. 

Return Value 

These functions return the integer found as a double (ceil) or a long double (ceill). 

Example  

 #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;
 }

Portability