10195 - The Knights Of The Round Table

#include<bits/stdc++.h>
#include<math.h>
using namespace std;
int main()
{
    double a,b,c,s,r;
    while(scanf("%lf%lf%lf", &a, &b, &c) !=EOF)
    {
        if(a==0 || b==0 || c==0)
         printf("The radius of the round table is: 0.000\n");
        else{s=(a+b+c)/2;
        r=(s-a)*(s-b)*(s-c);
        r=r/s;
        r=sqrt(r);
        printf("The radius of the round table is: %0.3lf\n",r);
        }
    }
    return 0;
}