C ++：最好将枚举作为值传递或作为const引用传递？ [英] C++: Is it better to pass an enum as a value or as a const reference?

问题描述

这里有两个相关的问题：

There are sort of two related questions here:

A）如何实现枚举？例如，如果我有代码：

A) How is enum implemented? For example, if I have the code:

enum myType
{ 
   TYPE_1,
   TYPE_2
};

实际发生了什么？我知道你可以将TYPE_1和TYPE_2视为int，但是它们实际上只是int？

What is actually happening? I know that you can treat TYPE_1 and TYPE_2 as ints, but are they actually just ints?

B）根据这些信息，假设传入的枚举没有需要更改，将myType作为值或作为const引用传递给函数更有意义吗？

B) Based on that information, assuming that the enum passed in didn't need to be changed, would it make more sense to pass myType into a function as a value or as a const reference?

例如，这是更好的选择： / p>

For example, which is the better choice:

void myFunction(myType x){ // some stuff }

或

void myFunction(const myType& x) { // some stuff }

推荐答案

速度明智，事物 - 任何体面的C ++编译器只是要传递一个int。

Speed wise it almost certainly doesn't matter - any decent C++ compiler is just going to pass a single int.

重要的是可读性 - 这将使你的代码更加明显的读者？

The important point is readability - which will make your code more obvious to the reader?

如果很明显这些枚举实际上只是int，那么我将它们的值传递，就像它们是int。使用const引用可能会导致程序员三思而后行（不是一个好主意）。

If it's obvious that these enums are really just ints then I would pass them by value, as if they were ints. Using the const ref might cause a programmer to think twice (never a good idea!)

但是 - 如果你以后要用类替换它们，相同和强制的常数可能是有意义的。

However - if you are later going to replace them with a class then keeping the API the same and enforcing the const-ness might make sense.

这篇关于C ++：最好将枚举作为值传递或作为const引用传递？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！