// Illustration of non-virtual destructors. Motivation for next version of the program.
#include <iostream>

using namespace std;

class A {
private:
   double a;
public:

  A(double a): a(a){};
  ~A(){cout << "A destructor" << endl;}
  // Class A is assumed to have virtual functions.
  //....
};

class B : public A {
private:
  double b;
public:
  B(double b): A(b-1), b(b){};
  ~B(){cout << "B destructor" << endl;}
  //...
};

void f(){
  A *a1 = new B(5.0);             // a1 points to a B object on the free store.
  B b1(6.0);                      // b1 contains a B object
  
  // Work on a1 and b1.
  // ....

  delete a1;                      // The destructor in A called 
                                  // The B destructor is not called. LEAK and PROBLEMS.
                                  // The destructor in A is not virtual.

  cout << "Now end of f" << endl;
  // B destructor   (object b1)   // b1 goes out of scope. It is destructed at 
  // A destructor   (object b1)   // ... both B and A level.
}  

int main(){
  f();
}