// Program indended to illustrate and discuss the rules of polymorphism 
// in C++ when we make use of private and public base classes.
// Answers in the next program - or per revealing of trailing comments.

#include <iostream>
#include <string>

using namespace std;

class B {
private:
  int b;
public:
  B(int b): b(b){}
  void Bop(){
    cout << "Bop()" << endl;
  }

};

class C {
private:
  int c;
public:
  C(int c): c(c){}
  void Cop(){
    cout << "Cop()" << endl;
  }
};

class D : private B, public C {
private:
  int d;
public:
  D(int b, int c, int d): B(b), C(c), d(d){} 
};

// Reveal...
int f(D &aD){           
  B *x = new D(1,2,3);  // Error: B is a private base
  C *y = new D(1,2,3);  // OK:    C is a public  base
  D *z = new D(1,2,3);  // OK, of course
  D *v = new B(1);      // Error: Against rules of polymorphism
  D *v = new C(1);      // Error: Against rules of polymorphism
}

int main(){
  D d(1,2,3);
  f(d);
}