Nineteenth International Obfuscated C Code Contest

Standard IOCCC stuff

View the index.html web page for the given winning entry for information on how on how to compile it and how to run the winning program. Look at the winning source and try to figure how it does what it does! You may then wish to look at the Author’s remarks for even more details.

Some ANSI C compilers are not quite as good as they should be. If yours is lacking, you may need to compile using gcc instead of your local compiler.

This year we included most of the information included by the submitters in the README.md files (that were used to build the index.html web pages).

Historical note:

The IOCCC has a website and now has a number of international mirrors. The primary website can be found at www.ioccc.org.

Historical update:

The IOCCC website once had a number of international mirrors. As of 2020 Dec 29, GitHub serves as the distributed server farm for the IOCCC winner repo that GitHub renders as Official IOCCC web site - www.ioccc.org.

Remarks on some of the entries

There were some outstanding entries that did not win. Unfortunately some very good entries lost because they:

depended too much on non-portable side effects in expressions;
depended too much on a particular byte order;
required the use of a special script, data file or pseudo-machine language that was not supplied with the entry.

We hope the authors of some of those entries will fix and re-submit them for the next IOCCC.

We believe you will be impressed with this year’s winning entries. The Best of Show is a fine example of (retro) obfuscation. But don’t ignore the other entries! There are games, puzzles, puzzle solvers, simulators, emulators, calculators and graphical and audio tools.

This year a single person won three awards and another two awards! Many authors won for the first time this year. (Please note that judging is done completely anonymously. Be warned that we may disqualify entries that reveal the identity of the submitter).

Final Comments

IMPORTANT NOTE: See contact.html for up to date contact details as well as details on how to provide fixes to any of the entries. See also the IOCCC FAQ for additional information on the IOCCC.