When you feed your code to something that supports infinite precision integers your program will end up printing non-primes! The question is, when does this happen and what would the sizeof(int) be?

The link to the winners and descriptions is, http://www.ioccc.org/2011/whowon.html

The IOCCC judges can be contacted by following these instructions. If you want to contribute your expertise or time to the IOCCC then please contact us.

Cute use of perl special characters and logical ops. For those that need hints. A regexp like (?{ <code> }) means run <code> as if it were perl. The <code> is constructed from exclusive or'ed strings that get concatenated. The resulting code is

print "I won",$/

$/ is the special variable for "input separator".

For other obfuscated code in C visit http://www.ioccc.org