Defined in header
float floor( float arg );
double floor( double arg );
long double floor( long double arg );
double floor( IntegralType arg );
|arg||-||floating point value|
 Return value
If no errors occur, the largest integer value not greater than
arg, that is ⌊arg⌋, is returned.
 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.
argis ±∞, it is returned, unmodified
argis ±0, it is returned, unmodified
- If arg is NaN, NaN is returned
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.
floor(+2.7) = 2.000000 floor(-2.7) = -3.000000 floor(-0.0) = -0.000000 floor(-Inf) = -inf
 See also
| nearest integer not less than the given value |
| nearest integer not greater in magnitude than the given value |
| nearest integer, rounding away from zero in halfway cases |
C documentation for floor