如何在c ++中正确使用虚拟成员函数

#include <iostream>

class Shape {
public:
    virtual void draw() const {
        std::cout << "Drawing a Shape" << std::endl;
    }
};

class Circle : public Shape {
public:
    void draw() const override {
        std::cout << "Drawing a Circle" << std::endl;
    }
};

class Rectangle : public Shape {
public:
    void draw() const override {
        std::cout << "Drawing a Rectangle" << std::endl;
    }
};

int main() {
    Shape *shape = new Circle();
    shape->draw();
    delete shape;

    shape = new Rectangle();
    shape->draw();
    delete shape;

    return 0;
}