std::floor,std::floorf,std::floorl (3) - Linux Manuals

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

NAME

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

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