Reference
C Library
IOstream Library
Strings library
STL Containers
STL Algorithms
Miscellaneous
C Library
cassert (assert.h)
cctype (ctype.h)
cerrno (errno.h)
cfloat (float.h)
ciso646 (iso646.h)
climits (limits.h)
clocale (locale.h)
cmath (math.h)
csetjmp (setjmp.h)
csignal (signal.h)
cstdarg (stdarg.h)
cstddef (stddef.h)
cstdio (stdio.h)
cstdlib (stdlib.h)
cstring (string.h)
ctime (time.h)
cmath (math.h)
functions:
abs
acos
asin
atan
atan2
ceil
cos
cosh
exp
fabs
floor
fmod
frexp
ldexp
log
log10
modf
pow
sin
sinh
sqrt
tan
tanh
macro constants:
HUGE_VAL


ceil

function
<cmath>
     double ceil (      double x );
      float ceil (       float x );
long double ceil ( long double x );

Round up value

Returns the smallest integral value that is not less than x.

Parameters

x
Floating point value.

Return Value

The smallest integral value not less than x.

Portability

In C, only the double version of this function exists with this name.

Example

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/* ceil example */
#include <stdio.h>
#include <math.h>
int main ()
{
  printf ("ceil of 2.3 is %.1lf\n", ceil (2.3) );
  printf ("ceil of 3.8 is %.1lf\n", ceil (3.8) );
  printf ("ceil of -2.3 is %.1lf\n", ceil (-2.3) );
  printf ("ceil of -3.8 is %.1lf\n", ceil (-3.8) );
  return 0;
}


Output:

ceil of 2.3 is 3.0
ceil of 3.8 is 4.0
ceil of -2.3 is -2.0
ceil of -3.8 is -3.0

See also

floor Round down value (function)
fabs Compute absolute value (function)
modf Break into fractional and integral parts (function)