访问继承中的私有成员 [英] access private members in inheritance

问题描述

我有一个A类，它有一个声明为private的字段val。
我想声明一个B类，它继承自A并且可以访问val。
有没有办法在C ++上实现？

I have a class A, which have a field val declared as private. I want to declare a class B, that inherit from A and have an access to val. Is there a way to do it on C++?

我想这样做是因为我需要重载A的一些函数，而根本不需要更改A代码。

I want to do it because I need to overload some functions of A, without changing A code at all.

谢谢。

推荐答案

快速回答：你没有。这是 protected 关键字的用途，如果你想授予对子类的访问权限，你想要使用它，而不是其他人。

Quick answer: You don't. Thats what the protected key-word is for, which you want to use if you want to grant access to subclasses but no-one else.

private 表示没有人可以访问这些变量，甚至没有子类。

private means that no-one has access to those variables, not even subclasses.

如果您根本无法更改 A 中的代码，可能会有 public / protected 该变量的访问方法。否则这些变量不能从子类访问，只有黑客可以帮助（我不鼓励！）。

If you cannot change code in A at all, maybe there is a public/protected access method for that variable. Otherwise these variables are not meant to be accessed from subclasses and only hacks can help (which I don't encourage!).

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