View Code of Problem 24

//（海伦公式）（p=(a+b+c)/2）
//             S=sqrt[p(p-a)(p-b)(p-c)]
#include<stdio.h>
#include<math.h>
int main(){
	double a,b,c;
	double p,s;
	while(scanf("%lf %lf %lf",&a,&b,&c)!=EOF){
	p=(a+b+c)/2;
	s=sqrt(p*(p-a)*(p-b)*(p-c));
	printf("%.2lf\n",s);
	}
}