虚函数在私有或保护继承 | 虚函数在私有或保护继承

本文介绍了虚函数在私有或保护继承的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

很容易理解公共继承中的虚函数。

It's easy to understand the virtual function in public inheritance. So what's the point for virtual function in private or protected inheritance?

例如：

class Base {
public:
virtual void f() { cout<<"Base::f()"<<endl;}
};

class Derived: private Base {
public:

void f() { cout<<"Derived::f()"<<endl;}

};

这是否仍然称为覆盖？这种情况的用途是什么？这两个f（）的关系是什么？

Is this still called overriding? What's the use of this case? What's the relationship of these two f()?

谢谢！

推荐答案

私有继承只是一种实现技术，不是一种关系，正如Scott Meyers在Effective C ++中所解释的：

Private inheritance is just an implementation technique, not an is-a relationship, as Scott Meyers explains in Effective C++:

class Timer {
public:
    explicit Timer(int tickFrequency);
    virtual void onTick() const; // automatically called for each tick
    ...
};

class Widget: private Timer {
private:
    virtual void onTick() const; // look at Widget private data
    ...
};

小部件客户端不应该能够在Widget上调用onTick，因为这不是概念小部件界面。

Widget clients shouldn't be able to call onTick on a Widget, because that's not part of the conceptual Widget interface.

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