在 C++ 中我应该把常量字符串放在哪里:静态类成员还是匿名命名空间?

问题描述

我需要定义一些只能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 文件的匿名命名空间中.它使它们对实现私有，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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