已知三角形三条边求面积

#include 
using namespace std;
int main()
{
	int a, b, c;
	float s, t;
	cin >> a >> b >> c;
	t = (a + b + c) / 2;
	s = sqrt(t*(t - a)*(t - b)*(t - c));
	cout << s << endl;
}