子类覆盖基类成员函数

Example 1:

#include <stdafx.h>
#include <iostream>
using namespace std;

class Base{
public:
    void func(){
        cout<<"Base::func"<<endl;
        return;
    }
};
class Derive:public Base{
public:
    void func(int c){
        cout<<"Derive::func"<<endl;
    }
};
int main(){
    Derive x;
    x.func(1);
    x.func();//error
    x.Base::func(); //ok
    return 0;
}

Example 2:

#include <stdafx.h>
#include <iostream>
using namespace std;

class Base{
public:
    virtual void func(){
        cout<<"Base::func"<<endl;
        return;
    }
};
class Derive:public Base{
public:
    void func(int c){
        cout<<"Derive::func"<<endl;
    }
};
int main(){
    Base *p=new Derive();
    p->func(); //print "Base::func"
    p->func(1);//error
    p->Derive::func(1) //error
    return 0;
}

上面两个例子中，派生类中重定义（不是重写）了基类的成员函数，造成覆盖，造成名字隐藏。即派生类对象不能直接调用父类的“被重定义”的成员函数；以派生类初始化的父类指针不能直接调用派生类成员函数