无法初始化私有const成员 [英] Unable to initialize private const member

问题描述

我想与我的课程相关联的 int 在该类的用户实例化它时设置。

I want to have an int associated with my class that is set when the user of this class instantiates it.

class MyClass {
public:
  MyClass(int x);
private:
  const int x;
};

要初始化此常量，我尝试使用构造器（Java样式）：

To initialize this constant, I try to use the contructor (Java style):

MyClass::MyClass(int x) {
  this->x = x;
}

但是，我的编译器不太喜欢这种方式，我得到了以下内容：

However, my compiler doesn't quite like it this way, and I get the following:

const.cxx: In constructor ‘MyClass::MyClass(int)’:
const.cxx:3:1: error: uninitialized const member in ‘const int’ [-fpermissive]
 MyClass::MyClass(int x) {
 ^
In file included from const.cxx:1:0:
const.h:8:13: note: ‘const int MyClass::x’ should be initialized
   const int x;
             ^
const.cxx:4:11: error: assignment of read-only member ‘MyClass::x’
   this->x = x;
           ^

基于构造函数la初始化实例化常量的C ++方法是什么Java吗？

What is the C++ way to initialize an instantiated constant based on the constructor a la Java?

编辑：我看到这个问题被标记为重复；该线程未能提及您可以在初始化器列表中使用构造函数的参数，因为它仅在所有示例中使用数字文字。

I saw the question marked as duplicate; that thread failed to mention you could use the constructor's parameters in the initializer list, since it only use numeric literals in all the examples.

推荐答案

您可以在构造函数的函数签名中使用所谓的初始化列表：

You can use what's called an initializer list in the constructor's function signature:

MyClass::MyClass(int x) : x(x) {
}

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