#include <iostream>
using namespace std;

class Shape {
public:
    virtual double area() {
        return 0;
    }
};

class Triangle : public Shape {
private:
    double base, height;

public:
    Triangle(double b, double h) {
        base = b;
        height = h;
    }

    double area() override {
        return (base * height) / 2;
    }
};

int main() {
    Shape* shape = new Triangle(10, 5);
    cout << "삼각형 넓이: " << shape->area() << endl;
    delete shape;
    return 0;
}