// abstract1.cpp
// with polymorphism, but doesn't work because of slicing with =
#include <iostream>
using namespace std;

class B {
public:
  virtual int get_val() { return 0; };
};

class D1 : public B {
public:
  D1(int x_val): x(x_val) {};
  virtual int get_val() { return x; };
private:
  int x;
};

class D2 : public B {
public:
  D2(int y_val): y(y_val) {};
  virtual int get_val() { return y*y; };
private:
  int y;
};

main()
{ const int MAX = 5;
  D1 Zero(0), One(1), Two(2);
  D2 Three(3), Four(4);

  B B_Array[MAX];
  B_Array[0] = Zero; B_Array[1] = One;
  B_Array[2] = Two;  B_Array[3] = Three; B_Array[4] = Four;

  for (int i = 0; i < MAX; ++i) {
    cout << i <<": " << B_Array[i].get_val() << endl;
  }
}