Design pattern : singleton, simple implementation in cpp

singleton.cpp

#include <iostream>
using namespace std;

class Singleton{
private:
	static Singleton *u_instance;
	int value;
	Singleton(int val) : value(val) {};
	~Singleton(){};

public:
	int get_value()
	{	
		return value;	
	}
	void set_value(int val)
	{	
		this->value = val;	
	}
	static Singleton *get_instance()
	{
		if (!u_instance)
			u_instance = new Singleton(0);
		return u_instance;
	}
};

// Allocation and initialization of the static data member
Singleton *Singleton::u_instance = 0;

int main(){
	cout << "singleton value : ";
	cout << Singleton::get_instance()->get_value() << endl;
	return 0;
}