Singleton Pattern（单例模式）

<pre name="code" class="cpp">/*Singleton.h*/
#ifndef SINGLETON_H
#define SINGLETON_H

class Singleton
{
public:
	static Singleton *Instance();
protected:
	Singleton();
private:
	static Singleton *instance_;
};
#endif

<pre name="code" class="cpp">/*Singleton.cpp*/
#include "Singleton.h"
#include <iostream>

Singleton *Singleton::instance_=0;

Singleton::Singleton()
{
	std::cout<<"Singleton..."<<std::endl;
}

Singleton *Singleton::Instance()
{
	if(instance_==0)
	{
		instance_=new Singleton();
	}
	return instance_;
}

/*main.cpp*/
#include "Singleton.h"

int main()
{
	Singleton *sgn=Singleton::Instance();
	return 0;
}