виртуальность

#include <iostream>
using namespace std;

class Foo {
    public:
    virtual void f() {
        cout << "Foo::f()" << endl;
    }
};

class Bar : public Foo {
    public:
    void f() {
        cout << "Bar::f()" << endl;
    }
};

class Tar : public Bar {
    public:
    void f() {
        cout << "Tar::f()" << endl;
    }
};


int main() {
    Tar t;
    Foo *f = &t;
    t.f();
    f->f();
    return 0;
}