[C++知识库]RALL再度探索

class TestObj
{
public:
	TestObj()
	{
		cout << "TestObj()\n";
	}

	~TestObj()
	{
		cout << "~TestObj()执行\n";
	}

	void showMsg()
	{
		cout << "showMsg()\n";
	}
};


class ManageObj
{
public:
	ManageObj(TestObj *pObj) :m_pObj(pObj)
	{

	}
	~ManageObj()
	{
		if (m_pObj)
		{
			delete m_pObj;
			m_pObj = NULL;
		}
	}
	TestObj*GetObj()
	{
		return m_pObj;
	}
protected:
private:
	TestObj *m_pObj;
};
void main()
{
	{
		ManageObj MO(new TestObj);
		MO.GetObj()->showMsg();

		//ManageObj Mb(MO);
	}
	system("pause");	
}

结果：

接着改变main()

void main()
{
	{
		ManageObj MO(new TestObj);
		MO.GetObj()->showMsg();

		ManageObj Mb(MO);//注意
		Mb.GetObj()->showMsg();
	}
	system("pause");	
}

结果：

所以一般RALL对象在复制自己时，应该一并复制它所管理的对象。我个人推介RALL对象就不要自己复制自己了。所以增加如下类：

class UnCopyAble
{
protected:
	UnCopyAble() = default;
	~UnCopyAble() = default;
private:
	UnCopyAble(const UnCopyAble&);
	UnCopyAble&operator=(UnCopyAble &o);
};

class ManageObj:private UnCopyAble
{
...
}

结果：直接在编译期间就扼杀了。