构造函数初始化列表求值顺序 [英] Constructor initialization-list evaluation order

问题描述

我有一个带有一些参数的构造函数.我曾假设它们是按照列出的顺序构建的，但在一种情况下，它们似乎是反向构建的，导致中止.当我反转参数时，程序停止中止.这是我正在使用的语法示例.问题是，在这种情况下， a_ 需要在 b_ 之前初始化.你能保证施工顺序吗?

I have a constructor that takes some arguments. I had assumed that they were constructed in the order listed, but in one case it appears they were being constructed in reverse resulting in an abort. When I reversed the arguments the program stopped aborting. This is an example of the syntax I'm using. The thing is, a_ needs to be initialized before b_ in this case. Can you guarantee the order of construction?

例如

class A
{
  public:
    A(OtherClass o, string x, int y) :
      a_(o), b_(a_, x, y) { }

    OtherClass a_;
    AnotherClass b_;
};

推荐答案

取决于类中成员变量声明的顺序.所以 a_ 将是第一个，然后 b_ 将是您示例中的第二个.

It depends on the order of member variable declaration in the class. So a_ will be the first one, then b_ will be the second one in your example.

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