求三角形面积 (sdut oj)

求三角形面积

Problem Description

Input

Output

Example Input

1 2 2.5

Example Output

0.950

Hint

Author

参考代码

#include<stdio.h>
#include<math.h>
double f(double a,double b,double c)
{
double s;
double p;
p = (a + b + c) / 2;
s = sqrt(p * (p - a) * (p - b) * (p - c));
return s;
}
int main()
{
double a,b,c;
double s;
scanf("%lf%lf%lf",&a,&b,&c);
s = f(a,b,c);
printf("%.3lf",s);
return 0;
}