何时使用 C++ 私有继承而不是组合? [英] When to use C++ private inheritance over composition?

问题描述

你能举一个具体的例子，什么时候最好使用私有继承而不是组合?就个人而言，我将使用组合而不是私有继承，但在某些情况下，使用私有继承可能是特定问题的最佳解决方案.阅读 C++ faq，为您提供了一个使用示例私有继承，但我似乎更容易使用组合+策略模式，甚至比私有继承更容易使用公共继承.

Can you give me a concrete example when is preferable to use private inheritance over composition? Personally, I will use composition over private inheritance, but there might be the case that using private inheritance is the best solution for a particular problem. Reading the C++ faq, gives you an example on using private inheritance, but I seems easier to use composition + strategy pattern or even public inheritance than private inheritance.

推荐答案

private 继承通常用于表示implemented-in-terms-of".我看到的主要用途是使用私有多重继承的 mixin 来构建具有来自各种 mixin 父项的适当功能的子对象.这也可以通过组合来完成(我稍微喜欢)，但是继承方法确实允许您使用 using 公开公开一些父方法，并且在使用 mixin 方法时允许使用更方便的符号.

private inheritance is typically used to represent "implemented-in-terms-of". The main use I have seen is for mixins using private multiple inheritance to build up a child object with the proper functionality from the various mixin parents. This can also be done with composition (which I slightly prefer) but the inheritance method DOES allow you to use using to expose some parent methods publicly, and allows for a slightly more convenient notation when using the mixin methods.

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