Entries written for IOCCC 27 (2020):

• 2020-minimd5
  An MD5 tool, with 64x4 byte constant table generation using integer arithmetic.

• 2020-rectangles
  Represents an image with the number of rectangles.

• 2020-lettermixer
  Randomizes the order of letters in words other than the first and last.

• 2020-markovchain
  Generates random text based on a dictionary using a Markov chain.

• 2020-jpegqs
  A smaller version of the jpeg-quantsmooth project. This entry did not win in 2020, was slightly refined and won at the IOCCC 28.

Below are the entries written for IOCCC 28. I expected the competition to take place in 2021, but it was only held in 2025.

Don't tell me that IOCCC 28 took place in 2024, the submission of works began in the last days of 2024, all judging and announcement of results took place in 2025, so I think the competition was held in 2025. The judges pulled off this trick to avoid missing the competition's 40th anniversary (which began in 1984).

• 2020-vm1
  This entry was written in August 2020, and I didn't think it was good enough. A new virtual machine was written to replace it in September 2020, which won at the next IOCCC 28 (in 2025).

• 2021-maze
  Started in July 2020, finished in January 2021. Did not win at IOCCC 28.

• 2020.08-atoi
  Implementation of the atoi() function.

• 2020.08-fizzbuzz
  A simple programming task asked in a job interviews.

• 2020.08-snake
  Fork of Cody Boone Ferguson's game from IOCCC 2020.

• 2020.08-expand
  A one-liner for expanding tabs.

• 2020.08-base64
  Base64 encoder.

• 2020.09-strlen
  Implementation of the strlen() function.

• 2020.10-concat
  An example of splitting a C program into separate characters.

• 2020.10-moon
  Draws the current moon phase to the console.

• 2020.10-hattifatteners
  Draws an SVG image with creatures from Moomin tales.

• 2020.12-perfume
  Spirit of X86.

• 2020.12-positive
  Most positive Hello World.

• 2020.12-heart
  The Heart of IOCCC.

• 2020.12-rot13
  R is for rot13.

• 2021.02-rle
  Run Length Printing.

• 2021.02-simd
  Dave Burton's one-liner from IOCCC 2020 in SIMD.

• 2021.05-gcd
  Greatest Common Divisor.

• 2021.05-hexdump
  Hexadecimal Dump.

• 2021.05-hellospiral
  No Strings Attached.

• 2021.07-http
  Micro HTTP server.

• 2022.04-hello++
  C++ operator overloading abuse.

• 2022.06-fizzbuzz++
  A way to torture an interviewer.

• 2022.06-crc64
  CRC64 checksum (ECMA-182 reflected, used in XZ).

• 2022.07-salvemondo
  A simple Italian to English translator.

• 2022.07-owlhw
  Hello World is encoded into a sequence similar to owl emoticons.

• 2022.07-crc32
  Unusual CRC32 function.

• 2022.09-doublehandy
  This suspicious code prints Hello World.

• 2022.12-hello++gcc
  Hello G++.

• 2023.02-hwitch
  A new technique for switch() that reduces emissions of semicolons and curly braces.

• 2023.08-k&r
  Exercises from Kernighan & Ritchie's "The C Programming Language (2nd edition)".

• 2025.08-goodbye_c89
  An ordinary Hello World, but not for C89.

Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)

Ilya Kurdyukov (twitter, github, linkedin)