07. Area of Figures

#include <iostream>

using namespace std;

int main() {
    string figure;
    cin >> figure;

    double area = 0;

    if (figure == "square") {
        double side;
        cin >> side;

        area = side * side;
    }
    else if (figure == "rectangle") {
        double length, width;
        cin >> length >> width;

        area = length * width;
    }
    else if (figure == "circle") {
        double radius;
        cin >> radius;

        area = 3.14159265359 * radius * radius;
    }
    else if (figure == "triangle") {
        double base, height;
        cin >> base >> height;

        area = base * height / 2;
    }

    cout.setf(ios::fixed);
    cout.precision(3);

    cout << area << endl;

    return 0;
}