// A1.cpp - implement derived copy constructor (also solution for A4)

#include <iostream>
using namespace std;

class A { 
  public:
    A() : myCount(++numObjects) {
      cout << "\n  void constructing A object"; 
    };
    A(const A &a) : myCount(++numObjects) {
      cout << "\n  copy constructing A object"; 
    };
    void say(const char *msg) { 
      cout << "\n      I am A object #" << myCount << " " << msg; 
    }
  private:
    int myCount;
    static int numObjects;
};

int A::numObjects = 0;

class B { 
  public:
    B() {
      cout << "\n  void constructing B object";
    }
    B(const B &b) : a(b.a) {
      cout << "\n  copy constructing B object";
    }
    virtual void say(const char *msg) { 
      cout << "\n    I am a B object " << msg;
      a.say("called from B"); 
    } 
  private: 
    A a; 
};

class D : public B { 
  public:
    D() {
      cout << "\n  void constructing D object";
    }
  ////// start of complete answer //////////////////
    D(const D &d) : B(d), a(d.a) {
      cout << "\n  copy constructing D object";
    }
  //// end of complete answer //////////////////////
    void say() {
      cout << "\n  I am a D object.";
      a.say("called from D");
      B::say("called from D");
    }
  private: 
    A a; 
};

void main() {

  D d1;
  d1.say();
  D d2 = d1;
  d2.say();
  cout << "\n\n";
}