#include <iostream>
 
class Base1{
public:
  virtual ~Base1(){}
};
 
class Base2{
public:
  virtual void f()=0;
  //virtual ~Base2(){}
};
 
class Derive: public Base1, public Base2{
public:
  void f(){ std::cout<<"f\n"; }
  ~Derive(){ std::cout<<"Derive dtor\n"; }
};
 
void func(Base2* p){
  p->f();
}
 
int main(int, char**){
  Derive* p = new Derive;
  Base1* pb1=p;
  Base2* pb2=p;
  func(p);
  //delete p;
  //delete pb1;
  delete pb2;
}