See, this is why I like HN. The discussion here is more interesting than the OP (which is, indeed, a very basic question that a little bit of research into the history of C would answer). I thought I knew about preprocessor magic (including stringification and variadic macros), but I'm glad to have run across this post (and the ensuing discussion) as I've learned something very useful from it (eg, how to construct more dynamic code in C/C++).