c++ typedef enum和just enum[副本]

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Why do you use typedef when declaring an enum in C++? 9 answers
为什么在c++中声明枚举时使用typedef ?9的答案

What exactly is the difference between:

到底有什么不同:

typedef enum {
  something1,
  something2,
  .....
  somethingN
} myEnum;

end just

结束只是

enum myEnum{
  something1,
  something2,
  .....
  somethingN
};

I know in first case I have typedefed unnamed enum, of course, just wonder which approach is better and why?

我知道在第一种情况下我输入了未命名的enum，当然，只是想知道哪种方法更好，为什么?

3 个解决方案

#1

The first variant was useful in C, because otherwise you would have to write enum myEnum everywhere you wished to use it.

第一个变体在C中是有用的，因为否则您必须在希望使用它的任何地方编写myEnum。

This is not the case in C++. So, AFAIK, there is no benefit to the first case in C++ (unless you're defining e.g. an interface that needs to be shared with C).

在c++中不是这样的。因此，AFAIK对于c++中的第一个例子没有任何好处(除非您定义了一个需要与C共享的接口)。

#2

No difference. In fact, the first version is C-style coding.

没有区别。事实上，第一个版本是c风格的编码。

C++11 has introduced stronly-typed enum, which you define as:

c++ 11引入了强类型enum，您将其定义为:

enum class myEnum  //note the 'class' keyword after the 'enum' keyword
{   
  something1,
  something2,
  .....
  somethingN
};

In C++03, enums are not type-safe, they're essentially integers, and can mix with other integral types implicitly, and another problem with them is that they don't have scope; you can use its member without qualifying its type; you can use something1. Whereas C++11 strongly-typed enums are type-safe, and they've scope; you've to use myEnum::something1.

在c++ 03中，枚举不是类型安全的，它们本质上是整数，可以隐式地与其他整数类型混合，另一个问题是它们没有作用域;您可以使用它的成员而不限定其类型;您可以使用something1。而c++ 11强类型的枚举是类型安全的，它们具有作用域;你使用myEnum::something1。

#3

I wouldn't use the first one. It is almost the same as the other one. In C++11, with the second you can write myEnum::something1 but not with the first one. Also in C++11, you can forward declare enums in some cases, but it is impossible to do forward declarations of unamed types and you can't forward declare typedefs either.

我不会用第一个。它几乎和另一个一样。在c++ 11中，有了第二个，您可以编写myEnum::something1，而不是第一个。在c++ 11中，您也可以在某些情况下转发declare enums，但是不可能执行unamed类型的转发声明，也不可能转发声明typedef。

#1