宏增加值，然后串联 [英] Macro increase value and then concatenate

问题描述

我想创建一个递归宏，它将创建下一个"类.

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

示例:

#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.

在连接之前，如何使编译器对此进行评估?

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

推荐答案

简单的答案是您做不到.预处理器通常处理文本和令牌.唯一的算术运算是在#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，并且不能用于进一步的替换.

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

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