C++翁恺学习19-向上造型

public inheritance should imply（意味着） substitution（代替）

if B is a A,you can use a B anywhere an A can be used

if B is a A, then everything that is true for A is also true of Bbe careful if the substitution if not valid

子类的对象可以当作父类来看待

#include 
using namespace std;

class A{
public:
	int i;
	A():i(10){};
};

class B:public A{
private:
	int j;
public:
	B():j(30){};
	void f(){
		cout<<"b.j="<upcasting is the act of converting from a Derived reference or pointer to a base class reference or pointer
upcasting examples 
Mannager pete("Pere"."88888888","Bakery");
Employee* ep = &pete;	//upcast 指针
Employee& er = pete;	//upcast 引用
 
lose type information about the object:
ep->print(cout);	//print base class version 使用的父类的函数
 
 
 
子类中的函数如果与父类中的函数重名则父类的中的函数隐藏