c++多态 函数重写与隐藏 (多态 虚函数表和指针)

先上代码:

class Base {
public:
    Base(){    };
    virtual ~Base(){ };
    virtual void FunA(){
        qDebug()<<"Base  FunA";
    };
    void FunB(){
        qDebug()<<"Base  FunB";
    };
    void FunBase(){
        qDebug()<<"Base  FunBase";
    };
};
class Derived : public Base
{
public:
    Derived(){    };
    ~Derived(){    };
    void FunA(){
        qDebug()<<"Derived  FunA";
    };
    void FunB(){
        qDebug()<<"Derived  FunB";
    };
    void FunDerived(){
        qDebug()<<"Derived  FunDerived";
    };
};

int main(int argc, char *argv[])
{
     QApplication a(argc, argv);

    Base *obj = new Derived;//obj指向Base的指针
    obj->FunA();//指向子类重写虚函数   //输出 Derived  FunA
    obj->FunB();//指向父类FunB()      //输出 Base  FunB
     qDebug()<<"--------------";
    Derived* obj2 = new Derived;//obj2 指向Derived的指针
    obj2->FunA();//指向子类重写虚函数     //输出 Derived  FunA
    obj2->FunB();//指向子类FunB()        //输出 Derived  FunB

    return a.exec();
}

输出:

Derived  FunA
Base  FunB
--------------
Derived  FunA
Derived  FunB

是个人理解:

1. 定义基类obj 指针指向基类, 调用非虚函数FunB()会调用基类的FunB();

2. obj2 指向Derived的指针, 调用与父类同名函数时候,父类的同名函数会被隐藏(就近原则);

3.上面举例有多态 继承 虚函数 虚函数表 隐藏 覆盖(重写虚函数) 等知识, 包括重载这里我都不写了