round to smallest integral value not less than x

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NAME

ceil

INTERFACE

#include <math.h>

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

DESCRIPTION

The ceil functions return the smallest integral value greater than or equal to x.

Example 1

#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;
}

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 ( &plusmn;0 ) returns &plusmn;0
ceil ( &plusmn;&infin; ) returns &plusmn;&infin;

SEE ALSO

abs (3) , fabs (3) , floor (3)

STANDARDS

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