Prepare for the winners of **IOCCC28**. > However these are not the 2024 droids you are looking for. :-) The HTML menu (both JavaScript and non-JavaScript) has been updated. The `Status -> Rules and guidelines' have been replaced with two separate menus `Status -> IOCCC rules` and `Status -> IOCCC guidelines`. Added a new top level `social.html` page: built from a new `social.md`. Sorted rules for building specific web pages in the top level `Makefile`. Added `make social` to make the `social.html` page from `social.md`. The `bin/gen-top-html.sh` now is able to process a argument of **social** to process the new top level `social.html` page. Changed `bin/gen-top-html.sh` VERSION from "2.0.0 2025-03-13" to "2.0.1 2025-07-25". Below `About -> Home page` a new `About -> IOCCC social media` menu item as added. Because the menu change touched every HTML file, we changed the general copyright date range for HTML files from "1984-2024" to "1984-2025" due to the extensive changes made for **IOCCC28**. Those markdown files that were modified in 2025 had their copyright date range also changed from "1984-2024" to "1984-2025". Rebuilt tarballs and sitemap due to the extensive HTML rebuilding. Ran `make update` to perform the above.
To build:
make
To use:
./bellard
Judges' remarks:
This code is a nice compact example of a Modular Fast Fourier Transform. While its output is very specific, the internal FFT has a wide variety of uses.
Can you modify this code to produce primes such as 23523*2^70000-1,
48594^65536+1 or 6917!-1?
NOTE: as bigger primes are found as time goes by this program no longer prints the biggest prime once noted by the author below.
Author's comments:
This program prints the biggest known prime number (2^6972593-1)
in base 10. It requires a few minutes. It uses a Modular Fast
Fourier Transform to compute this number in a reasonable amount
of time (the usual method would take ages !).
The program uses >= 64 bit long long type. It should run on any
system with a gcc compiler.