类声明问题. [英] A class declaration problem.

问题描述

我目前正在编写一个简单的C ++应用程序.我从网站上下载了一些源代码，但我不理解类声明.

这是代码；

I am currently programming a simple C++ application. I downloaded some source code from a website, but i don''t understand the a class declaration.

Here''s the code ;

class myClass
{
public:

	myClass(int sub) : main(sub) {} //what's up with this line ?
	int	main;

	int DoCalc();
};

请，需要帮助！

Please, Need help !

推荐答案

这些东西称为初始化列表".阅读有关此文章:
http://www.cprogramming.com/tutorial/initialization-lists-c++.html [ ^ ]

你可以说

That stuff is called the "initialization list". Read this article about it:
http://www.cprogramming.com/tutorial/initialization-lists-c++.html[^]

You could just say

main = sub;

如果是简单的int成员，则在构造函数主体中使用而不是在初始化程序列表中，但有时只有初始化程序列表才能完成此工作.例如，当您有一个基类或一个成员变量，其类型是没有默认构造函数的类时.对于属于您的班级成员的引用，也是如此.阅读链接文章，其中包含示例代码.

in the constructor body instead of the initializer list in case of a simple int member but sometimes only initializer lists can do the job. For example when you have a base class or a member variable whose type is a class that doesn''t have a default constructor. Same is true for a reference that is the member of your class. Read the linked article that has example code for these.

这基本上意味着，当使用该构造函数创建myClass的新成员时，变量main将获得值sub. 注意:您必须小心这些事情.它类似于调用基类的构造函数

It basically means that the variable main will get the value sub when the new member of myClass is created with that constructor
Note : you must be careful with these things . It resembles calling the constructor of base class

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