Using ceil() Function in C Programming

The ceil() function in the C language is used to return the smallest integer value that is greater than or equal to the input parameter (rounding up). This function is defined in the header file. The prototype of the ceil() function is as follows:

double ceil(double x);

One of which, x is a float parameter that represents the value needing to be rounded up. The ceil() function returns a double value that represents the smallest integer greater than or equal to x.

For example:

#include <stdio.h>
#include <math.h>

int main() {
    double x = 5.3;
    double result = ceil(x);
    
    printf("ceil(%.1f) = %.1f\n", x, result);
    
    return 0;
}

In the example above, ceil(5.3) will return 6.0, as 6.0 is the smallest integer value that is greater than or equal to 5.3.