#include <stdio.h>
#include <math.h>

// double pi= 3.1415926;
// const double pi= 3.1415926;

#define pi (4.0*atan(1.0))

double sqr(double x)
{
	return(x*x);
}

//     abs_diff(x, y)
double abs_diff(double x, double y)
{
	return(fabs(x - y));
}



// rel_diff(x, (no+1))
double rel_diff(double x, double y)
{
	double ax, ay, max;
	
	ax= fabs(x);
	ay= fabs(y);
	
	max= ((ax>=ay)?(ax):(ay));
	
	if (max > 0.0) {
		return(abs_diff(x, y)/ max);
	}
	else {// max == 0.0
	   return(0.0);
	}
	
}