在 C++ 中，我在哪里放置常量字符串:静态类成员或匿名命名空间?

2022-01-14 00:00:00 string static namespaces anonymous c++

我需要定义一些仅由一个类使用的常量字符串.看起来我有三个选择:

I need to define some constant strings that will be used only by one class. It looks like I have three options:

  1. 将字符串直接嵌入到使用它们的位置.

  1. Embed the strings directly into locations where they are used.

将它们定义为类的私有静态常量成员:

Define them as private static constant members of the class: 

//A.h  
class A {  
private:  
   static const std::string f1;  
   static const std::string f2;  
   static const std::string f3;  
};  

//A.cpp  
const std::string f1 = "filename1";  
const std::string f2 = "filename2";  
const std::string f3 = "filename3";  

//strings are used in this file

  • 在 cpp 文件的匿名命名空间中定义它们:

  • Define them in an anonymous namespace in the cpp file:

    //A.cpp  
namespace {  
  const std::string f1 = "filename1";  
  const std::string f2 = "filename2";  
  const std::string f3 = "filename3";  
}  

//strings are used in this file

    • 鉴于这些选项，您会推荐哪一个?为什么?谢谢.

    Given these options, which one would you recommend and why? Thanks.

    推荐答案

    我会将它们放在 CPP 文件中的匿名命名空间中.它使它们对实现是私有的，同时使其对作为实现一部分的非成员函数可见(例如 operator<<).

    I'd place them in anonymous namespace in the CPP file. It makes them private to the implementation and at the same moment makes it visible to the non-member functions that are part of implementation (such as operator<<).

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