std::floor,std::floorf,std::floorl (3) Linux Manual Page

std::floor,std::floorf,std::floorl – std::floor,std::floorf,std::floorl

Synopsis

Defined in header <cmath>
float floor ( float arg );
float floorf( float arg ); (since C++11)
double floor ( double arg ); (1) (2)
long double floor ( long double arg );
long double floorl( long double arg ); (3) (since C++11)
double floor ( IntegralType arg ); (4) (since C++11)
1-3) Computes the largest integer value not greater than arg.
4) A set of overloads or a function template accepting an argument of any integral_type. Equivalent to 2) (the argument is cast to double).

Parameters

arg – floating point value

Return value

If no errors occur, the largest integer value not greater than arg, that is ⌊arg⌋, is returned.

Return value

 math-floor.svg
Argument

Error handling

Errors are reported as specified in math_errhandling.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),

* The current rounding_mode has no effect.
* If arg is ±∞, it is returned, unmodified
* If arg is ±0, it is returned, unmodified
* If arg is NaN, NaN is returned

Notes

FE_INEXACT may be (but isn’t required to be) raised when rounding a non-integer finite value.
The largest representable floating-point values are exact integers in all standard floating-point formats, so this function never overflows on its own; however the result may overflow any integer type (including std::intmax_t), when stored in an integer variable.

Example

// Run this code

#include <cmath>

#include <iostream>

int main()

{
    std::cout << std::fixed
              << "floor(+2.7) = " << std::floor(+2.7) << '\n'
              << "floor(-2.7) = " << std::floor(-2.7) << '\n'
              << "floor(-0.0) = " << std::floor(-0.0) << '\n'
              << "floor(-Inf) = " << std::floor(-INFINITY) << '\n';
}

Output:

  floor(+2.7) = 2.000000
  floor(-2.7) = -3.000000
  floor(-0.0) = -0.000000
  floor(-Inf) = -inf

See also

ceil
ceilf
ceill nearest integer not less than the given value
         (function)
(C++11)
(C++11)
trunc
truncf
truncl nearest integer not greater in magnitude than the given value
         (function)
(C++11)
(C++11)
(C++11)
round
roundf
roundl
lround
lroundf
lroundl
llround
llroundf
llroundl nearest integer, rounding away from zero in halfway cases
         (function)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)