C ++：迭代所有的对象的成员？ [英] C++: Iterating through all of an object's members?

问题描述

假设我有一个拥有许多成员的对象：

Suppose I have an object with many members:

class Example {
    AnotherClass member1;
    AnotherClass member2;
    YetAnotherClass member3;
    ...
};

是否有简短的方法来做：

Is there a short/concise way to do something like:

foreach(member m: myExample)
    m.sharedMethod();

而不是逐一存取每个？

我想我可以把它们放在一个向量，并使用 shared_ptr 为同样的效果，我只是想知道如果说，Boost或一些其他流行的图书馆没有东西自动执行此操作。

I think I could put them in a vector and use a shared_ptr for the same effect, I was just wondering if say, Boost or some other popular library doesn't have something to do this automatically.

推荐答案

C ++不支持类自省，因此不能遍历类中的所有成员

C++ does not support class introspection, so you cannot iterate over all of the members in a class like that - not without having a (manually written) function that iterates over all members for you anyway.

原则上，您可以添加一个模板成员，如下所示：

You could, in principle, add a template member like so:

template<typename Functor>
void doAllMembers(Functor &f) {
  f(member1);
  f(member2);
  f(member3);
}

也就是说，我认为这是一个破碎的设计;你已经公开了你的所有内部成员。如果以后添加，会发生什么？或者改变一个的语义？将一个缓存的值设置为有时已过期？

That said, I would regard this as a broken design; you've gone and exposed all of your internal members publicly. What happens if you add one later? Or change the semantics of one? Make one a cached value that's sometimes out of date? etc. Moreover, what happens if you have members which don't all inherit from the same types?

退回并重新考虑您的设计。

Step back and reconsider your design.

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