std::fdim
From cppreference.com
| Defined in header <cmath>
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| float fdim( float x, float y ); |
(1) | (since C++11) |
| double fdim( double x, double y ); |
(2) | (since C++11) |
| long double fdim( long double x, long double y ); |
(3) | (since C++11) |
| Promoted fdim( Arithmetic1 x, Arithmetic2 y ); |
(4) | (since C++11) |
1-3) Returns the positive difference between x and y, that is, if x>y, returns x-y, otherwise (if x≤y), returns +0.
4) A set of overloads or a function template for all combinations of arguments of arithmetic type not covered by 1-3). 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
Run this code
#include <iostream> #include <cmath> #include <cerrno> #include <cstring> #include <cfenv> #pragma STDC FENV_ACCESS ON 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 raisedSee also
| (C++11) |
computes absolute value of an integral value (|x|) (function) |
| (C++11) |
larger of two floating point values (function) |
| C documentation for fdim
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