基类和派生类动态内存分配

[天台的故事]

#include <iostream>

using namespace std;

class Base
{
private:
	int * pBValue;
public:
	Base()
	{
		pBValue = NULL;
	}
	Base(const int B_M_temp)
	{
		pBValue = new int;
		*pBValue = B_M_temp;
	}
	Base(const Base &aa)
	{
		pBValue = new int;
		*pBValue = *(aa.pBValue);
	}
	Base & operator= (const Base &B_M_temp)
	{
		if (this == &B_M_temp)
		{
		  return *this;
		}
		pBValue = new int;
		*pBValue = *(B_M_temp.pBValue);

		return *this;
	}
	void set(const int B_M_temp)
	{
		*pBValue = B_M_temp;
	}
	void B_show() const
	{
		if (pBValue != NULL)
			cout << "Base: " << *pBValue << endl;
		else
			cout << "空指针" << endl;
	}
	~Base()
	{
		delete pBValue;
	}
};

class DeriveBase: public Base
{
private:
	int * DB_pValue;
public:
	DeriveBase()
	{
		DB_pValue = new int;
		*DB_pValue = 0;
	}
	DeriveBase(const int DB_M_temp, const int DB_M_temp1):Base(DB_M_temp1)
	{
		DB_pValue = new int;
		*DB_pValue = DB_M_temp;
	}
	DeriveBase(const DeriveBase &DB_M_temp):Base(DB_M_temp)
	{
		DB_pValue = new int;
		*DB_pValue = *(DB_M_temp.DB_pValue);
		
	}

	DeriveBase & operator= (const DeriveBase &DB_M_temp)
	{
		if (this == &DB_M_temp)
		{
		  return *this;
		}
		DB_pValue = new int;
		*DB_pValue = *(DB_M_temp.DB_pValue);

		return *this;
	}

	void DB_show() const
	{
		cout << "DeriveBase: " << *DB_pValue << endl;
		B_show();  
	} 
	~DeriveBase()
	{
		delete DB_pValue;
	}
};

int main()
{
	//定义一个基类 base 并初始化
	//输出基类
	Base base(8254);
	base.B_show();
	cout << endl;

	//定义一个基类 base1 并初始化
	//输出基类
	Base base1(base);
	base1.B_show();
    cout << endl;

	//定义一个基类 base2
	//给基类赋值一个值
	//复制一个基类对象到另一个基类对象
	//输出基类
	Base base2;
	base.set(123456789);
	base2 = base;
	base2.B_show();
	cout << endl;

    //定义一个派生类 dbase 并初始化
	//输出派生类
	DeriveBase dbase(100,2000);
	dbase.DB_show();
    cout << endl;
    
    //定义一个派生类 dbase 并初始化
	//输出派生类
	DeriveBase dbase1(dbase);
	dbase1.DB_show();
	cout << endl;

	//定义一个派生类 dbase 并初始化
	//复制一个派生类对象到另一个派生类对象
	//输出派生类
    DeriveBase dbase2;
	dbase2 = dbase1;
	dbase.DB_show();
	cout << endl;


	
	base2 = dbase2;  //这里使用派生类赋值给基类
	base2.B_show();
	cout << endl;
	

	return 0;
}

这个程序基类和派生类的数据成员都是动态内存分配的,这里有一个问题是,使用派生类赋值给基类,然后输出,代码应该怎么加.

base2 = dbase2;  //这里使用派生类赋值给基类
base2.B_show();
cout << endl;