TL;DR
The 29th IOCCC announced its winners for 2025, highlighting a range of creative and highly obfuscated C programs. The contest saw high-quality submissions from around the world, with notable entries including a Subleq computer and a GameBoy emulator.
The winners of the 2025 International Obfuscated C Code Contest (IOCCC) have been officially announced, with a diverse array of complex, creative, and highly obfuscated C programs recognized for their ingenuity. The announcement, made on the IOCCC’s official channels, marks the culmination of months of judging and highlights the contest’s ongoing role in celebrating programming artistry and technical skill.
The 2025 IOCCC saw a record number of submissions, with many authors building on past winners and pushing the boundaries of code obfuscation. The judging panel selected a range of winners, including notable entries such as a Subleq computer, a black hole punchcard Fortran program, and a GameBoy emulator. The winners were announced via a YouTube presentation and are now accessible through the IOCCC website, which hosts detailed source code, explanations, and links to presentation segments.
Among the winners was a new author from Taiwan, jingp49, marking a rare international addition to the list of previous winners. The contest also recognized multiple repeat winners, such as Yusuke Endoh, Nick Craig-Wood, and Don Yang, who each secured multiple awards this year. The entries demonstrated a wide range of programming challenges, from esoteric algorithms to innovative encoding techniques, reflecting the high level of skill and creativity in the community.
Why It Matters
The IOCCC remains a significant event in the programming community, emphasizing the artistic and technical aspects of code obfuscation. Its winners showcase extreme programming creativity and serve as educational resources for understanding complex C programming techniques. The contest’s visibility encourages innovation and experimentation, inspiring programmers worldwide to explore the limits of what can be achieved with C.
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Background
The IOCCC has been held annually since 1984, with a hiatus from 2020 to 2024. The 2025 contest marked a return to high participation levels, with submissions reaching near-historic heights in quality and quantity. The contest’s rules were substantially revised this year, aiming to improve clarity and organization, which may have contributed to the high caliber of entries. Past winners have often used the contest to demonstrate both technical mastery and artistic expression within the constraints of obfuscation.
“The 2025 entries exemplify the creativity and technical skill that make the IOCCC a unique celebration of programming artistry.”
— IOCCC Judge
“Winning entries continue to push the boundaries of what’s possible with obfuscated C code.”
— Yusuke Endoh
“It’s an honor to be part of this tradition and contribute a new international perspective.”
— Jingp49
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What Remains Unclear
Details about the specific judging criteria and the full list of honorable mentions remain undisclosed. It is also unclear how future submissions will evolve, or whether new categories will be introduced in subsequent contests.
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What’s Next
The IOCCC organizers plan to open submissions for the 30th contest towards the end of 2026, with judging expected to conclude in early 2027. They also plan to document the process thoroughly and encourage community engagement through fun challenges and potential improvements based on this year’s feedback.
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Key Questions
Who were the main winners of the 2025 IOCCC?
The main winners included entries such as a Subleq computer, a black hole punchcard Fortran program, a patch/diff quine, a GameBoy emulator, and a Zoltraak encoding project. Multiple repeat winners like Yusuke Endoh, Nick Craig-Wood, and Don Yang also secured awards.
How can I view the winning entries?
The winning source code and presentation segments are available on the IOCCC website, with links to YouTube videos and detailed explanations for each entry.
Will there be a 2026 IOCCC?
Yes, the organizers have announced plans to run IOCCC30 starting towards the end of 2026, with a similar duration and judging process as previous years.
What makes the IOCCC different from other coding contests?
The IOCCC emphasizes code obfuscation, artistic expression, and technical ingenuity rather than straightforward programming challenges, making it unique in celebrating the craft of complex, hidden, or playful code.
Source: Hacker News
