题解 | #计算三角形的周长和面积#

#include<bits/stdc++.h>
using namespace std;
int main() {
    double a, b, c;
    cin >> a >> b >> c;
    double C = (a + b + c) / 2;
    double S = sqrt(C * (C - a) * (C - b) * (C - c));
    cout << "circumference=" << fixed << setprecision(2) << C * 2 << " " << "area="
         << fixed << setprecision(2) << S << endl;
}