Landon Curt Noll
f29b37e49a
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
Bugs and (Mis)features:
The current status of this entry is:
STATUS: INABIAF - please DO NOT fix
For more detailed information see 2001/cheong in bugs.html.
To use:
./cheong digits
Try:
./try.sh
Judges' remarks:
Be sure to give an even number of digits in the argument. Add a leading 0 if needed.
The source code is nice, compact, and self documenting as all good programs should be! :-)
Author's remarks:
Operation
Compile normally and run with one argument, an integer with 2n digits. Program will return the integer part of its square root (n-digits). For example,
$ cc -o cheong cheong.c
$ ./cheong 1234567890
35136
$ ./cheong 0200000000000000000000000000
14142135623730
Deviation from these instructions will cause undefined results. :-)
Portability
This program runs normally on any ANSI C compiler and is ASCII dependent.
Strict compiling gives just one unavoidable warning:
gcc -ansi -Wall cheong.c
cheong.c:3: warning: third argument of `main' should probably be `char **'
Obfuscation
The main obfuscation is the algorithm used to calculate square roots, sometimes known as the longhand method. The basic algorithm is itself obfuscated in that it only uses subtraction to calculate square roots. For a detailed explanation, check Google or see Jack Crenshaw's article at https://web.archive.org/web/20011215124349/http://www.embedded.com/98/9802fe2.htm.
This program uses an even more obscured version which includes the following:
- A single string is used to store two numbers of different lengths
- Operations are done in a weird hybrid of base 10 and base 20
- Subtraction is done addition style, i.e.
4 - 8equals6carry a-1 - Recursive calls to
main()
Minor obfuscations:
- Self documenting whitespace in rectangular code block, for fun and glory (view with fixed-width font)
- Integer constants adjusted to less meaningful values, just for added confusion
- Hard-to-read, meaningless variable names to spite the reader
Challenges for the masses:
- What are the meanings [sic, plural] of the variable
o? - Why is
(c+999)%10-(D[I]+92)%10not equivalent to(c-D[I]+7)%10? - How does the program terminate?
- Is the programmer sane? ;-)
Appreciation
Thanks goes out to Bobby Rohde for numerous suggestions on how to shorten the program.