#include <iostream>
 #include <memory>

 using std::cout;
 using std::endl;
 using std::boolalpha;
 using std::weak_ptr;
 using std::shared_ptr;

 int main(){
   cout << boolalpha<< endl;

   auto sharedPtr=std::make_shared<int>(2011);
   weak_ptr<int> weakPtr(sharedPtr);
   cout << "weakPtr.use_count(): " << weakPtr.use_count() << endl;
   cout << "weakPtr.expired(): " << weakPtr.expired() << endl;

   if(shared_ptr<int> sharedPtr1 = weakPtr.lock()) {
     cout << "*sharedPtr: " << *sharedPtr << endl;
   }
   else{
     std::cout << "Don't get the resource!" << std::endl;
   }

   weakPtr.reset();
   if(shared_ptr<int> sharedPtr1 = weakPtr.lock()) {
     cout << "*sharedPtr: " << *sharedPtr << endl;
   }
   else{
     cout << "Don't get the resource!" << endl;
   }

   cout << endl;
 }