CPlusPlusThings/basic_content/virtual/set3/virtual_function1.cpp

#include <iostream>
using namespace std;

class Derived;

class Base {
public:
  virtual void fun() { cout << "Base Fun"; }
  //   friend int main();
};

class Derived : public Base {
private:
  void fun() { cout << "Derived Fun"; }
};

int main() {
  Base *ptr = new Derived;
  ptr->fun();
  return 0;
}