/*
**test28.cpp : Defines the entry point for the console application.
**系统winXP SP3 32位.
**类访问的动态绑定
*/
#include "stdafx.h"
#include "iostream.h"
class A{
public:
virtual void f(){
cout<<"A::fA1()"<<endl;
};
};
class B:public A{
public:
void f(){
cout<<"B::fB1()"<<endl;
};
};
class C:public B{
public:
void f(){
cout<<"C::fC1()"<<endl;
};
};
class D{
public:
virtual ~ D(){}
virtual void output(){};
};
class E:public D{
public:
E():eNum(0){}
virtual ~E(){}
virtual void output(int){
cout<<"E::fE1(int)"<<endl;
}
virtual void output(){
cout<<"E::fE1()"<<endl;
}
private:
int eNum;
};
int main(int argc, char* argv[])
{
A* pa = NULL;
A a;
B b;
C c;
a.f(); //fA1()
b.f(); //fB1()
c.f(); //fC1()
pa = &a;
pa->f(); //fA1()
pa = &b;
pa->f(); //fB1(),程序会根据动态绑定来确定具体调用的函数，若上面的父类A中函数不为virtual型，则此处调用的是fA1()
int iNum = 0;
D d;
D* pd= &d;
//pd->output(iNum); //错误
pd->output(); //空白输出
E* pe = new E;
pe->output(); //E::fE1()
pe->output(iNum); //E::fE1(int)
return 0;
}
Tips1：派生类的函数或成员变量会遮蔽掉父类中的同名函数或成员变量。
