没有名称的类 [英] Class with no name

问题描述

我在C ++标准文档中阅读了这个类：

I read this about class in the C++ standard document:

类是一个类型。它的名称在其
范围内成为类名（9.1）。

A class is a type. Its name becomes a class-name (9.1) within its scope.

class-name: identifier template-id

我发现C ++标准中的标识符的语法： / p>

I found this grammar for an identifier in the C++ Standard:

 2.10 Identifiers
 identifier: nondigit
 identifier nondigit
 identifier digit

 nondigit: one of universal-character-name 
 _ a b c d e f g h i j k l m n o p q r s t u  v w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
 digit: one of 0 1 2 3 4 5 6 7 8 9

现在我尝试这样做：

class
{
public:
  int i;
};

它编译正常，没有任何名称。

and it compiles fine without any name.

任何人都可以给我一个解释？是不是违反了为标识符指定的语法？

Can anyone give me an explanation regarding this? Isn't it a violation of the grammar specified for an identifier?

Nawaz问了关于标准的后续问题遵守我给予的守则。有兴趣的人可以在这里查看。 p>

Nawaz had asked a follow up question regarding the standard compliance of the code I had given. Those interested can check it out here.

推荐答案

语法

class-specifier:
    class-head { member-specification_opt }

class-head:
    class-key attribute-specifier-seq_opt class-head-name class-virt-specifier-seq_opt base-clause_opt
    class-key attribute-specifier-seq_opt base-clause_opt

class-key:
    class
    struct
    union

在你的情况下，第二个 class-head - 不涉及 class-name 。

In your case, the second production of class-head is used -- no class-name is involved.

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