std:: floor, std:: floorf, std:: floorl
|
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) |
|
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)
|
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 ), when stored in an integer variable.
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
|
|