lsp.cpp

#include <iostream>

using namespace std;

class Rectangle {
protected:
    int width;
    int height;

public:
    Rectangle(int width, int height) : width(width), height(height) {}

    virtual void set_width(int width) { this->width = width; };

    virtual void set_height(int height) { this->height = height; };

    int get_height() { return height; };

    int get_width() { return width; };

    int area() const { return width * height; }
};

class Square : public Rectangle {
public:
    Square(int size) : Rectangle(size, size) {}

    void set_width(int width) override { this->width = height = width; }

    void set_height(int height) override { this->height = width = height; }
};

void process(Rectangle &r) {
    int w = r.get_width();
    r.set_height(10);
    cout << "epected area  = " << w * 10 << ", got " << r.area() << endl;
}

int main() {
    Rectangle r{5, 5};
    process(r);

    Square s{5};
    process(s);
    return 0;
}