单例模式

/*  单例模式 */
class Singleton
{
private:
	static Singleton *s; /* private static */

	/* 构造函数声明为private */
    Singleton()
	{
	}

public:

	static Singleton* getInstance() /* 静态函数 */
	{
		if (NULL == s)
		{
			s = new Singleton;
		}
		
		return s;
	}

};
Singleton* Singleton::s = NULL;

int _tmain(int argc, _TCHAR* argv[])
{

	Singleton *s1 = Singleton::getInstance();
	cout<<s1<<endl;
	Singleton *s2 = Singleton::getInstance();
	cout<<s2<<endl;
	cout<<(s1==s2) <<endl; //1

	return 0;
}