fdim
From cppreference.com
| Defined in header
<math.h>
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| float fdimf( float x, float y );
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(1) | (since C99) |
| double fdim( double x, double y );
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(2) | (since C99) |
| long double fdiml( long double x, long double y );
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(3) | (since C99) |
| Defined in header
<tgmath.h>
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| #define fdim( x, y )
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(4) | (since C99) |
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) Type-generic macro: If any argument has type long double,
fdiml is called. Otherwise, if any argument has integer type or has type double, fdim is called. Otherwise, fdimf is called.
Contents |
[edit] Parameters
| x, y | - | floating point value |
[edit] 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.
[edit] 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
[edit] Notes
Equivalent to fmax(x-y, 0) except for the NaN handling requirements
[edit] Example
Run this code
#include <stdio.h> #include <math.h> #include <errno.h> #include <fenv.h> #pragma STDC FENV_ACCESS ON int main(void) { printf("fdim(4, 1) = %f, fdim(1, 4)=%f\n", fdim(4,1), fdim(1,4)); printf("fdim(4,-1) = %f, fdim(1,-4)=%f\n", fdim(4,-1), fdim(1,-4)); //error handling errno = 0; feclearexcept(FE_ALL_EXCEPT); printf("fdim(1e308, -1e308) = %f\n", fdim(1e308, -1e308)); if(errno == ERANGE) perror(" errno == ERANGE"); if(fetestexcept(FE_OVERFLOW)) puts(" FE_OVERFLOW raised"); }
Possible output:
fdim(4, 1) = 3.000000, fdim(1, 4)=0.000000
fdim(4,-1) = 5.000000, fdim(1,-4)=5.000000
fdim(1e308, -1e308) = inf
errno == ERANGE: Numerical result out of range
FE_OVERFLOW raised[edit] See also
| (C99)
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computes absolute value of an integral value (|x|) (function) |
| (C99)(C99)(C99)
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determines larger of two floating-point values (function) |
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C++ documentation for fdim
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