2011年5月14日 · What is the point of #define in C++? I've only seen examples where it's used in place of a "magic number" but I don't see the point in just giving that value to a variable instead.

How can I use #if inside #define in the C preprocessor? Asked 15 years, 8 months ago Modified 10 months ago Viewed 52k times

How do I define a function with optional arguments? Asked 13 years, 11 months ago Modified 1 year, 7 months ago Viewed 1.2m times

2017年3月4日 · #define simply substitutes a name with its value. Furthermore, a #define 'd constant may be used in the preprocessor: you can use it with #ifdef to do conditional compilation based on its …

The question is if users can define new macros in a macro, not if they can use macros in macros.

2009年10月28日 · Is it better to use static const variables than #define preprocessor? Or does it maybe depend on the context? What are advantages/disadvantages for each method?

In other words, when the compiler starts building your code, no #define statements or anything like that is left. A good way to understand what the preprocessor does to your code is to get hold of the …

2009年11月4日 · Which one is better to use among the below statements in C? static const int var = 5; or #define var 5 or enum { var = 5 };

As far as I know, what you're trying to do (use if statement and then return a value from a macro) isn't possible in ISO C... but it is somewhat possible with statement expressions (GNU extension). Since …

2011年7月12日 · I want to define a two-dimensional array without an initialized length like this: Matrix = [][] But this gives an error: IndexError: list index out of range