宏增加值然后连接

Macro increase value and then concatenate(宏增加值然后连接)

问题描述

我想创建一个递归宏来创建下一个"类.

I want to create a recursive Macro the will create the "next" class.

例子:

#define PRINTME(indexNum) class m_##(indexNum+1) { }

indexNum + 1 被评估为 int，并且不会连接到类名.

The indexNum + 1 is evaluated as an int, and won't concatenate to the class name.

如何让编译器在连接之前对其进行评估?

How can I cause the compiler to evaluate that, before concatenating?

推荐答案

简单的答案是你不能.预处理器一般处理文本和标记；唯一的算术是在 #if 和 #elif 指令中进行的.

The simple answer is that you can't. The preprocessor generally deals in text and tokens; the only place arithmetic is carried out in in #if and #elif directives.

此外，宏扩展不是递归的.在扩展过程中，正在扩展的宏被禁用，并且不可用于进一步替换.

Also, macro expansion isn't recursive. During expansion, the macro being expanded is disabled, and is not available for further substitution.

这篇关于宏增加值然后连接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编程学习网！