string concatenation with macro

Question

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Macro for concatenating two strings in C

How to concatenate two strings with a macro?

I tried this but it does not give correct results:

#define CONCAT(string) "start"##string##"end"

Answer 1

You need to omit the ##: adjacent string literals get concatenated automatically, so this macro is going to concatenate the strings the way you want:

#define CONCAT(string) "start"string"end"

For two strings:

#define CONCAT(a, b) (a"" b)

Here is a link to a demo on ideone.