std::ceil

 

C++

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Common mathematical functions

Functions
Basic operations
abs(int) labs llabs imaxabs (C++11) abs(float) fabs div ldiv lldiv imaxdiv (C++11) fmod	remainder (C++11) remquo (C++11) fma (C++11) fmax (C++11) fmin (C++11) fdim (C++11) nan nanf nanl (C++11) (C++11) (C++11)
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Error and gamma functions
erf (C++11) erfc (C++11)	lgamma (C++11) tgamma (C++11)
Nearest integer floating point operations
ceil floor round lround llround (C++11) (C++11) (C++11)	trunc (C++11) nearbyint (C++11) rint lrint llrint (C++11) (C++11) (C++11)
Floating point manipulation functions
ldexp scalbn scalbln (C++11) (C++11) ilogb (C++11) logb (C++11)	frexp modf nextafter nexttoward (C++11) (C++11) copysign (C++11)
Classification/Comparison
fpclassify (C++11) isfinite (C++11) isinf (C++11) isnan (C++11) isnormal (C++11) signbit (C++11)	isgreater (C++11) isgreaterequal (C++11) isless (C++11) islessequal (C++11) islessgreater (C++11) isunordered (C++11)
Macro constants
HUGE_VALF HUGE_VAL HUGE_VALL (C++11) (C++11) INFINITY (C++11) NAN (C++11) math_errhandling MATH_ERRNO MATH_ERREXCEPT (C++11)	FP_NORMAL FP_SUBNORMAL FP_ZERO FP_INFINITE FP_NAN (C++11) (C++11) (C++11) (C++11) (C++11)

 

Defined in header <cmath>
float       ceil( float arg );
double      ceil( double arg );
long double ceil( long double arg );
double      ceil( Integral arg );		(since C++11)

Computes nearest integer not less than arg.

Parameters

arg

-

floating point value

Return value

Nearest integer not less than arg

Return value

Argument

Notes

If the argument is infinity (positive or negative) or zero (positive or negative), the return value is the same as the argument.

The largest representable floating-point values are exact integers in all standard floating-point formats, so this function never overflows.

This function may, but is not required to, raise FE_INEXACT floating-point exceptions for non-integer arguments.

Example

run this code

#include <cmath>
#include <iostream>
 
int main()
{
    std::cout << std::fixed;
    std::cout << std::ceil(12.0) << '\n';
    std::cout << std::ceil(12.1) << '\n';
    std::cout << std::ceil(12.5) << '\n';
    std::cout << std::ceil(12.9) << '\n';
    std::cout << std::ceil(13.0) << '\n';
}

Output:

12.000000
13.000000
13.000000
13.000000
13.000000

See also

floor	nearest integer not greater than the given value (function)
trunc (C++11)	nearest integer not greater in magnitude than the given value (function)
round lround llround (C++11) (C++11) (C++11)	nearest integer, rounding away from zero in halfway cases (function)
rint lrint llrint (C++11) (C++11) (C++11)	nearest integer using current rounding mode with exception if the result differs (function)
nearbyint (C++11)	nearest integer using current rounding mode (function)