Landon Curt Noll
2b92c89be8
Entry source is now prog.c for IOCCC years 2014 thru 2020, or is now dirname.c IOCCC years 1984 thru 2013. To achieve this state, we renamed the following: renamed: 2004/hibachi/src/hibachi.c -> 2004/hibachi/hibachi.c renamed: 2012/omoikane/nyaruko.alt.c -> 2012/omoikane/omoikane.alt.c renamed: 2012/omoikane/nyaruko.alt2.c -> 2012/omoikane/omoikane.alt2.c renamed: 2012/omoikane/nyaruko.c -> 2012/omoikane/omoikane.c renamed: 2012/omoikane/nyaruko.orig.c -> 2012/omoikane/omoikane.orig.c Modified `bin/subst.entry-index.sh` to add to entry `index.html` file, links to the `Makefile` and the _C code_ to the top navigation bar. Changed `bin/subst.entry-index.sh` VERSION from "1.2.2 2024-02-25" to "1.3 2024-03-02". Moved printing the Inventory link in the top navigation bar from `bin/subst.entry-navbar.awk` to `bin/subst.entry-index.sh`. Changed `bin/subst.entry-navbar.awk` VERSION from "1.0.1 2024-02-23" to "1.1 2024-03-02". Moved printing the Inventory link in the top navigation bar from `bin/subst.year-navbar.awk` to `bin/subst.year-index.sh`. Changed `bin/subst.year-index.sh` VERSION from "1.0 2024-02-11" to "1.1 2024-03-02". Changed `bin/subst.year-navbar.awk` VERSION from "1.0 2024-02-11" to "1.1 2024-03-02". Added location names (both default and common) to `author.html`. Changed `tmp/gen_author_json.sh` VERSION from "1.0 2023-06-06" to "1.1 2024-03-04". Added location names (both default and common) to `author.html`. Changed `bin/gen-authors.sh` VERSION from "1.2 2024-03-09" to "1.3 2024-03-04". The manifest and the resulting `.entry.json` files have been changed for `2004/hibachi` and `2012/omoikane`. The Makefiles for `2004/hibachi` and `2012/omoikane` copy the source file into the "previously used location". The `make clobber` rule removes the copied source. The `.gitignore` files have been updated accordingly. Improved how the concept of IOCCC terms _entry_, _author_ and _submission_ are used in markdown files. Links to markdown files (files ending in .md) within the repo were changed to link to HTML files (files ending in .html). Special cases where `README.md` became `index.html` were modified accordingly. Fixed URL for `bugs.html` in Makefile comments. Fixed name of `bin/sgi.sh` referenced in comments in `.gitignore` files. Links to locations within the repo are now relative. For example a link to `/contact.html` may become `../contact.html' or '../../contact.html` depending on the directory level of the markdown file. Nearly all links with absolute URLs under _https://www.ioccc.org_ or `https://ioccc-src.github.io/temp-test-ioccc_ have been changed to relative paths within the repo. Some exceptions to this (such as referring to a GitHub repo) were preserved. Fixed a number of inside `faq.md` and `bugs.md`. Added HTML name tags (in the form of an _entry_id_) for each entry referenced in `bugs.md`. Fixed links from outside of `bugs.html` into `bugs.html` accordingly. Where FAQ entries are referenced, a named tag is used so that if a FAQ is ever renumbered, links outside of `faq.html` will still work. Changed the _inventory_order_ of a compressed tarball from _300_ to _100000_. While this may have been done for the manifest, this changed had not yet been propagated into the `.entry.json` files. Links to web sites that were in the for <URL> are now [URL](URL). Performed `name www` to process all of the above. Improved format of `authors.html`. Full names are now bold. Location codes are now links back into `location.html` and location names (both default and common) are now italics. Added _author_handle_ each author. Changed `bin/gen-authors.sh` VERSION from "1.1 2024-02-25" to "1.2 2024-03-09". Improved format of `location.html` as location codes are now bold, author counts in a given location are now bold, and location names (both default and common) are now italics. Changed `bin/gen-location.sh` VERSION from "1.0.1 2024-02-23" to "1.1 2024-03-04". Added italic location name after location code in entry `index.html` files. Changed `bin/output-index-author.sh` VERSION from "1.4.1 2024-02-23" to "1.5 2024-03-04". Added _Location of authors_ to the sidebar as a link to `location.html`. TODO: While nearly all of the above mentioned changes are likely correct, they likely introduced a few errors that need correcting.
To build:
make
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.
Copyright and CC BY-SA 4.0 License:
This file is Copyright (c) 2023 by Landon Curt Noll. All Rights Reserved. You are free to share and adapt this file under the terms of this license:
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
For more information, see: https://creativecommons.org/licenses/by-sa/4.0/