#include <iostream>
using namespace std;

class Singleton final{//The final keyword to make the class as terminal class
	Singleton() { // Private Constructor to prevent instantiation outside the class
		cout<<"The singleton preparation goes here...."<<endl;
	}
    //static Singleton instance;	//Non Lazzy initialization	
public:
	~Singleton(){
		cout<<"Release any allocated resources here..."<<endl;
	}
    /* Explicitly disallow copying. */ 
    Singleton(const Singleton&) = delete;
    Singleton& operator=(const Singleton&) = delete;

    /* In C++03, the above would be written as
         Singleton(const Singleton&){}
         Singleton& operator= (const Singleton&){}
    */
	static Singleton& UniqueInstance() {
    	static Singleton instance;	//Lazzy initialization
    	return instance;
	} 
	void InstanceOperation(){
		cout<<"Calling instance operation..."<<endl;
	}
};

//Singleton Singleton::instance; //Non Lazzy initialization	

//class SubSingleton: public Singleton{
//	
//};

int main(){
    Singleton& s1 = Singleton::UniqueInstance();//Using synonym
    //Singleton& s2 = Singleton::UniqueInstance();
    //s1.InstanceOperation();
    //Singleton *ps = &Singleton::UniqueInstance();//Using pointer
    //ps->InstanceOperation();
	//cout<<hex<<&s1<<endl;	
	//cout<<hex<<&s2<<endl;	
	//s1 = s2;//Assignment
	//Singleton s3 = s1;//Initialization
	//cout<<"&s1 is "<<hex<<&s1<<endl;
	//cout<<"&s2 is "<<hex<<&s2<<endl;
	//cout<<"&s3 is "<<hex<<&s3<<endl;
	return 0;
}