# carlini/printf-tac-toe

tic-tac-toe in a single call to printf

Repository: https://github.com/carlini/printf-tac-toe
Canonical: https://ross.abutalabs.com/products/printf-tac-toe
Language: C
License: GPL-3.0
License Family: copyleft
Last push: 2022-06-08T08:33:53+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 2302, "days_push": 1547, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2531, forks 63 (observed 2026-08-28T04:06:58.869691+00:00)

## What it is
A C program that plays tic-tac-toe using a single call to printf, written for the International Obfuscated C Code Contest 2020. It encodes a full game loop and AI logic entirely within a printf format string and argument list.

## Use cases
- play tic-tac-toe from the terminal
- study extreme obfuscated C techniques
- see how printf format strings can compute
- IOCCC entry demonstration
- learn about %n format specifier tricks

## When to choose
- you want a famous obfuscated C curiosity to explore or demo
- you're studying IOCCC-winning style code or printf abuse

## When to avoid
- you need a real, maintainable tic-tac-toe game
- you want production-quality or portable C code
- you need a game with a graphical interface

## Facets
- artifact type: application
- maturity: experimental
- function: interpreter, developer-tools
- domain: programming-languages, gaming-tools
- platform: windows, cli, cpp
- tags: obfuscated-c, ioccc, printf-turing-machine, novelty, c, tic-tac-toe, code-golf, algorithms, linux, macos

## Member repositories
- carlini/printf-tac-toe (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:58.869691+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:25:19.512678+00:00, confidence not recorded.
  - readme: https://github.com/carlini/printf-tac-toe (fetched 2026-08-28T04:06:58.869691+00:00, sha 2bdf727a58de)
- Data as of 2026-08-30T08:39:29.467469+00:00.