Code Witchery Abounds as the IOCCC Celebrates the Strangest C Programs for its 25th Year
After a one year break, the International Obfuscated C Code Contest is back to showcase the strangest and most challenging-to-comprehend C programs, in the 25th iteration of their event. Their list of awards, announced a few months back, but with the source code of winning projects just released last month, is as idiosyncratic as ever, including the "Most Shifty" C program as well as "Most Likely to be Awarded." Many of these are cryptic hints by judges Leo Broukhis, Simon Cooper, and Landon Curt Noll, who further share their remarks in hint files with (sometimes vague) spoilers. This allows reader to try the programs and discover the behavior of these tiny, strange programs on their own.
Why obfuscate code? And why, in particular, using C? Nothing so directly defies conventional coding standards -- the Dijsktrean aesthetic of clear, self-documenting programs -- than Obfuscated Code, the practice of writing intentionally inscrutible programs. As pointed out in Nick Montfort and Michael Matteas's "A Box Darkly", the aesthetic of IOCCC winners may be at odds with traditional aesthetic of code, but they still assert its C-ness, often using aspects like pointer confusion that less often occur in other languages. Kernighan and Ritchie's slim C book (which many of us used to first learn the langauge) makes the language appear simple and elegant -- but as Montfort and Matteas argue, "clarity in C code is achieved only with effort." The IOCCC winners put their effort toward achieving the opposite of clarity, exploiting lesser known features of the language, and tactics that fall far from the norms of programming. Even after 25 years, there are winners with novel approaches, such as hou's entry, which makes wonderful use of preprocessor directives and avoids variable names entirely.
Contrast the IOCCC with the much-shorter-run Perl obfuscated code contest. Perl is easy to obfuscate, to the point that the esolangs wiki lists Perl as an esoteric language as is. C is perhaps more fun to obfuscate because its perceived simplicity and air of refinement (along with its continued widespread usage, while Perl now has a very much reduced, if still very enthusiastic userbase). The pleasure of this code is in breaking conventional approaches to discover the little known features, the tricks and hacks. It's a call back to code's beginnings as a dark art before the days of high level languages, an idea analyzed in the early chapters of Wendy Chun's excellent Programmed Visions.
Notes on some of the winning entries here