C++ Smart Pointers

#include <iostream>
#include <memory>
using namespace std;

struct Resource {
  string name;
  Resource(string n) : name(n) { cout << "create " << name << endl; }
  ~Resource() { cout << "destroy " << name << endl; }
};

int main() {
  {
    unique_ptr<Resource> a = make_unique<Resource>("A");
    cout << "using " << a->name << endl;
  }  // a is destroyed here
  cout << "after block" << endl;

  shared_ptr<Resource> b = make_shared<Resource>("B");
  {
    shared_ptr<Resource> c = b;
    cout << "owners: " << b.use_count() << endl;
  }
  cout << "owners: " << b.use_count() << endl;
  return 0;
}

create A
using A
destroy A
after block
create B
owners: 2
owners: 1
destroy B