std::floor, std::floorf, std::
Defined in header <cmath>
|
||
| (1) | ||
|
float floor (
float num )
;
double floor ( double num ); |
(until C++23) | |
|
constexpr
/*floating-point-type*/
floor ( /*floating-point-type*/ num ) ; |
(since C++23) | |
|
float floorf( float num );
|
(2) | (since C++11) (constexpr since C++23) |
|
long
double floorl(
long
double num )
;
|
(3) | (since C++11) (constexpr since C++23) |
SIMD overload (since C++26) |
||
Defined in header <simd>
|
||
|
template
<
/*math-floating-point*/ V >
constexpr /*deduced-simd-t*/<V> |
(S) | (since C++26) |
Additional overloads (since C++11) |
||
Defined in header <cmath>
|
||
|
template
<
class Integer >
double floor ( Integer num ) ; |
(A) | (constexpr since C++23) |
std::floor for all cv-unqualified floating-point types as the type of the parameter.
(since C++23)
|
S) The SIMD overload performs an element-wise
std::floor on v_num.
|
(since C++26) |
A) Additional overloads are provided for all integer types, which are treated as double.
|
(since C++11) |
Parameters
| num | - | floating-point or integer value |
Return value
If no errors occur, the largest integer value not greater than num, that is ⌊num⌋, 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.
- If num is ±∞, it is returned, unmodified.
- If num is ±0, it is returned, unmodified.
- If num 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
The additional overloads are not required to be provided exactly as (A). They only need to be sufficient to ensure that for their argument num of integer type, std::floor(num) has the same effect as std:: floor ( static_cast < double > (num) )
Example
#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
|
(C++11)(C++11)
|
nearest integer not less than the given value (function) |
|
(C++11)(C++11)(C++11)
|
nearest integer not greater in magnitude than the given value (function) |
|
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
|
nearest integer, rounding away from zero in halfway cases (function) |
C documentation for floor
| |