Cody Boone Ferguson
3deb7ae603
Amongst the changes here is that we do not need to have the hex or html
code (numbers) for open and close parentheses (in links) as there are
names. '(' is & followed by lpar; and the ')' is the same but 'rpar;'
instead. This makes it easier to remember and type and it generates the
same html as well (they are all valid). Now the markdown files are
consistent in this (in some cases hex was used and in others the html
code).
Although many markdown files were updated no html files needed to be
updated as it generates the same html. Even so I ran the appropriate
rules to do so just to verify this.
169 lines
5.1 KiB
Markdown
169 lines
5.1 KiB
Markdown
## To build:
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``` <!---sh-->
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make
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```
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## To use:
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``` <!---sh-->
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./endoh2 > pi.c
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gcc -o pi pi.c
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./pi > 314.c
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```
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and:
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``` <!---sh-->
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./endoh2 e > e.c
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gcc -o e e.c
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./e > 271.c
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```
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...
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## Try:
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``` <!---sh-->
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./try.sh
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```
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## Judges' remarks:
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A
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[pi](https://en.wikipedia.org/wiki/Pi)/[e](https://en.wikipedia.org/wiki/E_(mathematical_constant))
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printing quasi-[quine](https://en.wikipedia.org/wiki/Quine_(computing)) in [ASCII
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art](https://en.wikipedia.org/wiki/ASCII_art) with a compressed font in it; what
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else to wish for in this program? [Virtual
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machine](https://en.wikipedia.org/wiki/Virtual_machine) emulation?
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## Author's remarks:
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Yeah, "Again". Sorry. But I don't feel guilty or uncomfortable.
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This entry is based on 'over-used themes' such as self reproducing
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program and [pi](https://en.wikipedia.org/wiki/Pi) or
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[e](https://en.wikipedia.org/wiki/E_(mathematical_constant)) computation. I
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know you're tired of them.
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But have you ever seen them **all-in-one**?
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### What it is
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This program generates a new program in the shape of the Greek letter
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`pi`. Then, the generated program:
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- computes 3 digits of pi and prints it as an ASCII-art program that:
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- computes 4 digits of pi and prints it as an ASCII-art program that:
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- computes 5 digits of pi and prints it as an ASCII-art program that:
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- computes 6 digits of pi and prints it as an ASCII-art program that:
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- ...
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One more thing... When you give a command line argument `e` to the
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first program, the generated one will compute [Napier's
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constant](https://en.wikipedia.org/wiki/E_(mathematical_constant))
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rather than pi.
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### Obfuscation
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This program itself is in the shape of a
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[spigot](https://en.wikipedia.org/wiki/Tap_(valve)). This is derived as an
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analogy with [spigot algorithm](https://en.wikipedia.org/wiki/Spigot_algorithm)
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which infinitely computes the value of a mathematical constant such as
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[pi](https://en.wikipedia.org/wiki/Pi) or
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[e](https://en.wikipedia.org/wiki/E_(mathematical_constant)).
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The two sets of programs, `314*.c` and `271*.c`, are almost the same
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except their shape and constant computational part. I tailored the
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common part to parse in both shapes (`3.14...` and `2.71...`), by
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tweaking the computational order and adding meaningless code fragments.
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On the other hand, to make it fit inside one screen (80 x 25), my program is
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shortened properly, more than it looks. (As you may know,
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[quines](https://en.wikipedia.org/wiki/Quine_(computing)) need to make its
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program size doubled.) For example, this program involves 3x5 bitmap font data
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of ten characters (`0` -- `9`), as just 20 bytes: `G1%xJ{;Q7wunmuGuu%uu`. We
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can decode character `n` as `275*s[n+10] - 8*s[n] - 8`. I solved the system of
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[Bézout's identity](https://en.wikipedia.org/wiki/B%C3%A9zout%27s_identity) to
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find the magic string, with the aid of a brute force. See `find-font-table.rb`
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in detail.
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I used many other tricks for short coding.
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I'm sorry that many ASCII-art-style winning entries of
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[IOCCC](../../years.html) ignore [C preprocessor
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directives](https://en.wikipedia.org/wiki/C_preprocessor). In my program,
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`#include` is a part of ASCII-art with comments padded.
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These design requirements made my program well-obfuscated
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willy-nilly.
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### Portability
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I expect it to work in any major environment and C compiler. To build with no
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warning, it requires two C99 features: allow string literal to be more than 509
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characters and not requiring a return in `main()`. In fact, recent compilers
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with `-std=c99 -Wall -W -Wextra -pedantic` would say nothing.
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``` <!---sh-->
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gcc -std=c99 -Wall -W -Wextra -pedantic spigot.c
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clang -std=c99 -Wall -W -Wextra -pedantic spigot.c
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```
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I've tested with gcc-4.6.3 and clang-3.0 on Linux (Ubuntu 12.04)
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and gcc-4.5.3 and clang-3.1 on Cygwin.
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### Synopsis
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``` <!---sh-->
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cc endoh2.c -o endoh2
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./endoh2 > pi.c
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cat pi.c
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cc pi.c -o pi ; ./pi > 314.c ; cat 314.c
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cc 314.c -o 314 ; ./314 > 3141.c ; cat 3141.c
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cc 3141.c -o 3141 ; ./3141 > 31415.c ; cat 31415.c
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cc 31415.c -o 31415 ; ./31415 > 314159.c ; cat 314159.c
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cc 314159.c -o 314159 ; ./314159 > 3141592.c ; cat 3141592.c
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etc...
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./endoh2 e > e.c
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cat e.c
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cc e.c -o e ; ./e > 271.c ; cat 271.c
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cc 271.c -o 271 ; ./271 > 2718.c ; cat 2718.c
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cc 2718.c -o 2718 ; ./2718 > 27182.c ; cat 27182.c
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cc 27182.c -o 27182 ; ./27182 > 271828.c ; cat 271828.c
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cc 271828.c -o 271828 ; ./271828 > 2718281.c ; cat 2718281.c
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etc...
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```
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You can do `make everything` for the process (with no `cat`).
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Note: The executable may return a failure (non-zero) exit status
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unless `-std=c99` option is given.
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<!--
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Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
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You are free to share and adapt this file under the terms of this license:
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Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
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For more information, see:
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https://creativecommons.org/licenses/by-sa/4.0/
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-->
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