ceil

Round to smallest integral value not less than x

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Contents

Interface
Description
Special Values
See Also
Standards
Page Comments

Interface

#include <math.h>double  ceil (double x)
long  ceill (long double x)
float  ceilf (float x)

Description

The ceil function returns the smallest integral value greater than or equal to x.

Example:

Example - Round to smallest integral value not less than x

Workings

#include <stdio.h>
#include <math.h>
int main(void)
{
  for(double a = 12; a < 13; a += 0.1)
    printf("ceil of  %.1lf is  %.1lf\n", a, ceil(a));
  return 0;
}

Solution

Output

ceil of  12.0 is  12.0
ceil of  12.1 is  13.0
ceil of  12.2 is  13.0
ceil of  12.3 is  13.0
ceil of  12.4 is  13.0
ceil of  12.5 is  13.0
ceil of  12.6 is  13.0
ceil of  12.7 is  13.0
ceil of  12.8 is  13.0
ceil of  12.9 is  13.0
ceil of  13.0 is  13.0

Special Values

ceil ( ±0 ) returns ±0.

ceil ( ±&infin ) returns ±∞.

Standards

The ceil function conform to ISO/IEC 9899:1999(E).

double	`ceil` (double x)
long	`ceill` (long double x)
float	`ceilf` (float x)