#include <iostream>

using std::cout;
using std::endl;

class Base {
 public:
  virtual void f1() {
    cout << "Base::f1()" << endl;
  }
  virtual void f2() {
    cout << "Base::f2()" << endl;
  }
};

class Der1: public Base {
 public:
  virtual void f1() {
    cout << "Der1::f1()" << endl;
  }
};

int main(int argc, char **argv) {
  Base b;
  Der1 d1;
  d1.f1();
  Base *bptr = &d1;
  bptr->f1();

  return 0;
}