"Prefers C++" means "implemented his winning entry in C++". This isn't terribly unusual. According to http://en.wikipedia.org/wiki/ICFP_Programming_Contest htt

"Prefers C++" means "implemented his winning entry in C++". This isn't terribly unusual. According to http://en.wikipedia.org/wiki/ICFP_Programming_Contest http://en.wikipedia.org/wiki/ICFP_Programming_Contest it seems that C-family entries won in 1998, 2003, 2007, 2008, and now 2009.