Re: delete does not work

Below is a simple code:

#include <iostream>

class base{
public:
  base(): i(11){std::cout<<"base constructor"<<'\n';}
  virtual void f() = 0;
  virtual ~base(){ std::cout<<"base destructor"<<'\n';}
  int i;
};

class derv1 : public base{
public:
  derv1(){std::cout<<"derv1 constructor"<<'\n';}
  void f(){}
  ~derv1(){std::cout<<"derv1 destructor"<<'\n';}
};

class derv2 : public derv1{
public:
  derv2(){i=22;std::cout<<"derv2 constructor"<<'\n';}
  ~derv2(){std::cout<<"derv2 destructor"<<'\n';}
};

int main(){
  base *b1;
  derv1 *d1;

  derv2 *d2 = new derv2;

  b1 = d2;
  std::cout<<b1<<" "<<d2->i<<'\n';
  delete b1; //LINE1

  std::cout<<"after delete d1"<<'\n';
  std::cout<<b1->i<<" "<<d2->i<<'\n'; //LINE2
}

I delete b1 at LINE1. Why LINE2 still output the correct result---22?

Thanks.

Jack