Updated: 09/22/2017 by Computer Hope

The Internet Obfuscated C Code Contest (IOCCC), is a sometimes-annual competition between computer programmers that began in 1984. Contest entries must be written in the C programming language, in an obscure or obfuscated way. Winning programs have a purpose that is unclear, hidden, or cleverly designed.

As of 2017, 24 IOCCC competitions have taken place, with 2018 suggested as the likely year of the 25th competition.

An example of a winning program is "duble", winner of the 2015 prize for "best handwriting." The code for the program looks like this:

2015 IOCCC winner (duble) source code

When compiled and executed, this program uses Unicode characters to draw animated handwritten letters in your terminal, like this:

2015 IOCCC winner duble, sample output

For more information and source code to winning programs, visit

Obfuscation, Programming definitions