/*
 * singleton.cpp
 *
 * Singleton example.  Ensure a class has only one instance
 * and provide a global point of access.
 */

#include <iostream>

class Singleton {

public:

  static Singleton& instance() {
    static Singleton s;

    return s;
  }

  void operation() {
    std::cout << "Singleton " << this << "\n";
  }

  ~Singleton() {}

protected:
  Singleton() {};
};

int main() {

  Singleton& s1 = Singleton::instance();
  s1.operation();

  Singleton& s2 = Singleton::instance();
  s2.operation();
}