单例模式

#include <iostream>
using namespace std;

class Singleton
{
private:
    Singleton() {}
    //把复制构造函数和=操作符也设置为私有，防止被复制
    Singleton(const Singleton&) {}
    Singleton& operator=(const Singleton&) {}

    static Singleton* obj;

public:
    static Singleton* GetObj()
    {
        if(obj == NULL)
            obj = new Singleton();
        else
            return obj;
    }
};

//在此处初始化
Singleton* Singleton:: obj = NULL;

int main()
{
    Singleton* singleton1 = Singleton::GetObj();
    Singleton* singleton2 = Singleton::GetObj();

    if(singleton1 == singleton2)
        printf("singleton1 == singleton2\n");
    return 0;
}