std::fdim, std::fdimf, std::fdiml
Defined in header <cmath> |
||
---|---|---|
float fdim ( float x, float y ); |
(1) | (since C++11) (constexpr since C++23) |
float fdimf( float x, float y ); |
(2) | (since C++11) (constexpr since C++23) |
double fdim ( double x, double y ); |
(3) | (since C++11) (constexpr since C++23) |
long double fdim ( long double x, long double y ); |
(4) | (since C++11) (constexpr since C++23) |
long double fdiml( long double x, long double y ); |
(5) | (since C++11) (constexpr since C++23) |
Promoted fdim ( Arithmetic1 x, Arithmetic2 y ); |
(6) | (since C++11) (constexpr since C++23) |
1-5) Returns the positive difference between
x
and
y
, that is, if
x>y
, returns
x-y
, otherwise (if
x≤y
), returns
+0
.
6) A set of overloads or a function template for all combinations of arguments of
arithmetic type not covered by
(1-5). If any argument has
integral type, it is cast to
double
. If any argument is
long double
, then the return type
Promoted
is also
long double
, otherwise the return type is always
double
.
Parameters
x, y | - | values of floating-point or integral types |
Return value
If successful, returns the positive difference between x and y.
If a range error due to overflow occurs, +HUGE_VAL
, +HUGE_VALF
, or +HUGE_VALL
is returned.
If a range error due to underflow occurs, the correct value (after rounding) is returned.
Error handling
Errors are reported as specified in math_errhandling
.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
- If either argument is NaN, NaN is returned
Notes
Equivalent to std::fmax(x-y, 0)
, except for the NaN handling requirements.
Example
#include <iostream> #include <cmath> #include <cerrno> #include <cstring> #include <cfenv> #ifndef __GNUC__ #pragma STDC FENV_ACCESS ON #endif int main() { std::cout << "fdim(4, 1) = " << std::fdim(4, 1) << " fdim(1, 4) = " << std::fdim(1, 4) << '\n' << "fdim(4,-1) = " << std::fdim(4, -1) << " fdim(1,-4) = " << std::fdim(1, -4) << '\n'; // error handling errno = 0; std::feclearexcept(FE_ALL_EXCEPT); std::cout << "fdim(1e308, -1e308) = " << std::fdim(1e308, -1e308) << '\n'; if (errno == ERANGE) std::cout << " errno == ERANGE: " << std::strerror(errno) << '\n'; if (std::fetestexcept(FE_OVERFLOW)) std::cout << " FE_OVERFLOW raised\n"; }
Output:
fdim(4, 1) = 3 fdim(1, 4) = 0 fdim(4,-1) = 5 fdim(1,-4) = 5 fdim(1e308, -1e308) = inf errno == ERANGE: Numerical result out of range FE_OVERFLOW raised
See also
(C++11)
|
computes absolute value of an integral value (\(\small{|x|}\)|x|) (function) |
(C++11)(C++11)(C++11)
|
larger of two floating-point values (function) |
C documentation for fdim |
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