UVA 10522 Height to Area

#include <queue>
#include <stack>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <limits.h>
#include <string.h>
#include <string>
#include <algorithm>
using namespace std;
const double eps = 1e-8;
bool dy(double x,double y)	{	return x > y + eps;}	// x > y 
bool xy(double x,double y)	{	return x < y - eps;}	// x < y 
bool dyd(double x,double y)	{ 	return x > y - eps;}	// x >= y 
bool xyd(double x,double y)	{	return x < y + eps;} 	// x <= y 
bool dd(double x,double y) 	{	return fabs( x - y ) < eps;}  // x == y
int main()
{
	int ncases;
	double x,y,z;
	
	scanf("%d",&ncases);
	
	while( ncases )
	{
		scanf("%lf%lf%lf",&x,&y,&z);
		if( dd(x,0.0) || dd(y,0.0) || dd(z,0.0) )
		{
			printf("These are invalid inputs!/n");
			ncases--;
			continue;
		}
		double p =  (1/x +  1/y + 1/z)*(1/y + 1/z - 1/x)*(1/x + 1/z - 1/y)*(1/x + 1/y - 1/z);
		if( xyd(p,0.0) )
		{
			printf("These are invalid inputs!/n");
			ncases--;
			continue;
		}
		double area = 1/sqrt(p);
		
		printf("%.3lf/n",area);
	}
return 0;
}