Calculate the length of the hypotenuse for a right-angled triangle
#include <math.h> double hypot( double x, double y ); float hypotf( float x, float y ); long double hypotl( long double x, long double y );
These functions compute the length of the hypotenuse for a right triangle whose sides are x and y adjacent to the right angle. The calculation is equivalent to:
length = sqrt( x*x + y*y );
To check for error situations, use feclearexcept() and fetestexcept(). For example:
The length of the hypotenuse.
If: | These functions return: | Errors: |
---|---|---|
The correct value would cause overflow | Inf | FE_OVERFLOW |
x or y is ±Inf, and the other is any value including NaN | Inf | — |
x or y is NaN, and the other isn't ±Inf | NaN | — |
The correct result would cause underflow | The correct result, after rounding | FE_UNDERFLOW |
These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.
#include <stdio.h> #include <math.h> #include <fenv.h> #include <stdlib.h> int main( void ) { int except_flags; feclearexcept(FE_ALL_EXCEPT); printf( "%f\n", hypot( 3.0, 4.0 ) ); except_flags = fetestexcept(FE_ALL_EXCEPT); if(except_flags) { /* An error occurred; handle it appropriately. */ } return EXIT_SUCCESS; }
produces the output:
5.000000
Safety: | |
---|---|
Cancellation point | No |
Interrupt handler | No |
Signal handler | No |
Thread | Yes |