#include <iostream>
using std::cout;
using std::endl;
 
#include <memory>
 
struct Base {
   Base() { cout << "b" << endl; }
   virtual ~Base() { cout << "~b" << endl; }
};
 
struct Derived : Base {
   Derived() { cout << "d" << endl; }
   ~Derived() { cout << "~d" << endl; }
};
 
int main() {
   std::shared_ptr<Base> pB;
   {
     std::shared_ptr<Derived> pD(new Derived);
     pB = pD;
     cout << "End of Block" << endl;
   }
   cout << "End of Main" << endl;
}
 

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