单例模式之C++实现

#include "stdafx.h"
#include <iostream>
using namespace std;

class Singleton
{
private:
    static Singleton *m_instance;
    Singleton()
    {
        cout << "Singleton Construct" << endl;
    }
    ~Singleton()
    {
        if (m_instance)
        {
            delete m_instance;
        }
        cout << "Singleton Destruct" << endl;
    }
public:
    static Singleton* GetInstance()
    {
        if (!m_instance)
        {
            m_instance = new Singleton;
        }
        return m_instance;
    }
};

Singleton* Singleton::m_instance = NULL;


int main()
{
    //Singleton *pSingletonA = new Singleton;  //编译会报错，因为不能访问私有函数
    Singleton *pSingletonA = Singleton::GetInstance();
    Singleton *pSingletonB = Singleton::GetInstance();

    if (pSingletonA == pSingletonB)
        cout << "Same Instance" << endl;
    return 0;
}