【C++】繼承派生中對象相互賦值情況

標籤：派生   繼承   類   對象賦值   c++   

//繼承派生中對象相互賦值情況//衍生類別的對象可以賦值給基類的對象，這時是把衍生類別對象中從對應基類中繼承來的隱藏對象賦值給基類對象。//反過來不行，因為衍生類別的新成員無值可賦。#include <iostream>using namespace std;class B{public:B(){cout<<"B"<<endl;}void fun(){cout<<"B::fun()"<<endl;}private:int x;};class D : public B{public:D(){cout<<"D"<<endl;}void fun(){cout<<"D::fun()"<<endl;}void show(){cout<<"D::show()"<<endl;}private:int y;};void main(){B b;b.fun();D d;d.fun();b = d;    //正確，把大的給小的，給局部賦值//d = b;    錯誤，小的給大的，不能賦值  }<img src="http://img.blog.csdn.net/20150512213119072?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvZG91ZG91d2ExMjM0/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

【C++】繼承派生中對象相互賦值情況