#include <math.h>
float hypotf(float x, float y);
hypotf compute the square root of the sum of the squares of x and y, sqrtf(x*x + y*y), without undue overflow or underflow. If x and y are the lengths of the sides of a right-angled triangle, then hypotf computes the length of the hypotenuse..
If x or y is +? or -?, hypotf
returns ?.
If x or y is NaN, hypotf
returns NaN.
hypotf conforms to ISO/IEC 9899:1999 (C99).