使用初始化器列表初始化包含const数组的结构体 [英] Initialize a Struct containing a const array with initializer list

问题描述

我使用C ++ 11并且有一个包含以下结构的类：

  struct设置{
 const std :: string name; 
 
 const std :: string * A; 
 const size_t a; 
}; 
 
 class X {
 static const设置s; 
 //更多的东西
}; 
  

在 .cpp 像这样定义

  X :: s = {MyName，{one，two，three }，3}; 
  

但这不起作用。但它使用中间变量工作

  const std :: string inter [] = {one，two 三}; 
 X :: s = {MyName，inter，3};有没有办法没有中间变量？
 
 
 div class =h2_lin>解决方案

指针不能从值列表中初始化。您可以改用 std :: vector ：

  #include<向量> 
 
 struct设置{
 const std :: string name; 
 const std :: vector< std :: string>一个; 
 // ^^^^^^^^^^^^^^^ 
 const size_t a; 
}; 
  

然后您可以写：

  class X {
 static const Settings s; 
 //更多的东西
}; 
 
 const设置X :: s = {MyName，{one，two，three}，3} 
  

这里是 。

如Praetorian在建议中所建议，您可能需要替换 std ::向量与 std :: array ，如果您可以明确指定容器的大小，如果大小不需要在运行时更改：

  #include< array> 
 
 struct设置{
 const std :: string name; 
 const std :: array< std :: string，3>一个; 
 // ^^^^^^^^^^^^^^^^^ 
 const size_t a; 
}; 
  

这里是 生活示例 。

I working with C++11 and have a Class containing the following Struct:

struct Settings{
    const std::string name;

    const std::string* A;
    const size_t a;
};

class X {
    static const Settings s;
    //More stuff
};

In the .cpp file I want to define it like this

X::s = {"MyName", {"one","two","three"}, 3};

But this does not work. However it does work using an intermediate variable

const std::string inter[] = {"one","two","three"};
X::s = {"MyName", inter, 3};

Is there a way to do it without the intermediate variable?

解决方案

A pointer cannot be initialized from a list of values. You could use std::vector instead:

#include <vector>

struct Settings{
    const std::string name;
    const std::vector<std::string> A;
//        ^^^^^^^^^^^^^^^^^^^^^^^^
    const size_t a;
};

You can then write:

class X {
    static const Settings s;
    //More stuff
};

const Settings X::s = {"MyName", {"one","two","three"}, 3};

Here is a live example.

As suggested by Praetorian in the comments, you may want to replace std::vector with std::array, if it is acceptable for you to specify the size of the container explicitly, and if the size does not need to change at run-time:

#include <array>

struct Settings{
    const std::string name;
    const std::array<std::string, 3> A;
//        ^^^^^^^^^^^^^^^^^^^^^^^^^^
    const size_t a;
};

And here is the live example.

这篇关于使用初始化器列表初始化包含const数组的结构体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！