#include <iostream>
#include <memory>

using namespace std;

struct MyClass
{
  shared_ptr<MyClass> next;

  MyClass(shared_ptr<MyClass> next)
  {
    this->next = next;
    cout << "Constructor completed for a MyClass object." << endl;
  }

  virtual ~MyClass()
  {
    cout << "Destructor completed for a MyClass object." << endl;
  }
};

int main() 
{
  shared_ptr<MyClass> nullp;
  shared_ptr<MyClass> sp1(new MyClass(nullp));
  shared_ptr<MyClass> sp2(new MyClass(sp1));

  {
    cout << "Entered inner block." << endl;
    shared_ptr<MyClass> sp3(new MyClass(sp2));
    sp1->next = sp3;	// Create cyclic referencing
    cout << "sp3 use count: " << sp3.use_count() << endl;
    cout << "Leaving inner block." << endl;
  }
  cout << "Left inner block." << endl;

  cout << "sp1 use count: " << sp1.use_count() << endl;
  cout << "sp2 use count: " << sp2.use_count() << endl;
  cout << "sp3 use count: " << sp1->next.use_count() << endl;

  sp1.reset();
  sp2.reset();

  cout << "Released sp1 and sp2, dtors still not executed." << endl;

  return 0;
}