String concatenation using preprocessor

Question

is it possible to concatenate strings during preprocessing?

I found this example

#define H \"Hello \"
#define W \"World!\"
#define HW H W

printf(HW)         


        

Answer 1

Concatenation of adjacent string litterals isn't a feature of the preprocessor, it is a feature of the core languages (both C and C++). You could write:

printf("Hello "
       " world\n");