#include <iostream>
#include <memory>
 
using namespace std;
 
struct MyClass
{
  MyClass() { cout << "MyClass ctor runned." << endl; }
  ~MyClass() { cout << "MyClass dtor runned." << endl; }
};
 
int main() 
{
  shared_ptr<MyClass> sp1(new MyClass);
  cout << "Use count: " << sp1.use_count() << endl;
 
  shared_ptr<MyClass> sp2 = sp1;
  cout << "Use count: " << sp1.use_count() << endl;
 
  sp1.reset();
  cout << "Use count: " << sp2.use_count() << endl;
 
  {
    cout << "Entered inner block." << endl;
    shared_ptr<MyClass> sp3 = sp2;
    cout << "Use count: " << sp2.use_count() << endl;
    cout << "Leaving inner block." << endl;
  }
  cout << "Left inner block." << endl;
  cout << "Use count: " << sp2.use_count() << endl;
 
  cout << "About to delete the last shared pointer." << endl;
  sp2.reset();
  cout << "Deleted the last shared pointer." << endl;
 
  return 0;
}

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