Singleton模式

2019独角兽企业重金招聘Python工程师标准>>>

template <typename T>
class Singleton
{
protected:
Singleton(){}
virtual~Singleton(){}
public:
	static T* GetInstancePtr()
	{
		if (!m_pInstance)
		{
			m_pInstance=new T;
		}
		return m_pInstance;
	}

	static T  GetInstance()
	{
		if (m_pInstance)
		{
			m_pInstance=new T;
		}
	    return *m_pInstance;
	}

	static void ReleaseInstancePtr()
	{
		if (m_pInstance)
		{
			delete m_pInstance;
			m_pInstance=nullptr;
		}
	}

public:
	static T*  m_pInstance;
};
template <typename T>
T* Singleton<T>::m_pInstance=nullptr;

class A :public Singleton<A>
{
public:
	A(){}
	~A(){}
public:
	void Test(){printf("this is a A\n");}
};
//Singleton模式 
class B
{
public:
	B(){}
	~B(){}
public:
	void Test(){printf("this is a B\n");}
};


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

	A::GetInstancePtr()->Test();
	//A::GetInstancePtr()->GetInstancePtr()->GetInstancePtr()->Test();
	A* pa1=A::GetInstancePtr();
	A* pa2=A::GetInstancePtr();
	pa1->Test();
	pa2->Test();
	A::ReleaseInstancePtr();
	//OR
	Singleton<A>::GetInstance().Test();
	Singleton<A>::GetInstancePtr()->Test();
	Singleton<A>::ReleaseInstancePtr();

	Singleton<B>::GetInstance().Test();
	Singleton<B>::GetInstance().Test();
	Singleton<B>::ReleaseInstancePtr();

    //Singleton模式 

	getchar();
	return 0;
}

转载于:https://my.oschina.net/u/221120/blog/884195