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.
c++ - Why use #define instead of a variable - Stack Overflow
How can I use #if inside #define in the C preprocessor? Ask Question Asked 15 years, 11 months ago Modified 1 year, 1 month ago
2 what's happening when you define something without giving a definition? Every valid #define directive associates a macro name with a corresponding replacement list (a "definition", in your terms). An empty replacement list is allowed, and there's nothing special about that as far as the preprocessor is concerned.
Is it possible to write a #define that defines a #define? For example:
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 preprocessed output and look at it.
c++ - What does ## in a #define mean? - Stack Overflow
The #define directive is a preprocessor directive; the preprocessor replaces those macros by their body before the compiler even sees it. Think of it as an automatic search and replace of your source code. A const variable declaration declares an actual variable in the language, which you can use... well, like a real variable: take its address, pass it around, use it, cast/convert it, etc. Oh ...