std::ceil

 

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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

#include <cmath>
#include <iostream>
 
int main()
{
    double a = 12.0;
    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)