#include <iostream> 
class A{ 
public: 
   A(){ std::cout << "A"; } 
   virtual ~A(){ std::cout << "~A"; } 
}; 
class B: public A{ 
public: 
   B(){ std::cout << "B"; } 
   ~B(){ std::cout << "~B"; } 
}; 
 
int main(){ 
   A * a = new B(); 
   delete a; 
   return 0; 
}