Author:

• Name: NATORI Shin
  Location: JP - Japan

To build:

    make

An alt version exists for those in the southern hemisphere (or those who want to see what it would be in the southern hemisphere). See Alternate version below.

To use:

    ./natori

Try:

    ./try.sh

Try running this on different days, say a few days apart (even better if the Moon phase changes), and each time run it several times in a row (or several times in a day).

Also try modifying the code so that it will show another Moon phase based on input or else just by the code itself. Bonus points if you can make it show all.

NOTE: if it’s a Full Moon the script won’t look as nice.

Alternate code:

The author noted that those in the southern hemisphere might want to change acos(l/2) into acos(-l/2) which we have done in the alternate version.

Alternate build:

To build the alternate code that works for the southern hemisphere:

    make alt

Alternate use:

    ./natori.alt

Try running this on different days, say a few days apart, and each time run it several times in a row (or several times in a day).

What happens if you run it in the northern hemisphere? Are there any differences?

Can you identify any Moon phases that result in the same output of both versions? Or are there any?

Alternate try:

    ./try.alt.sh

Like with try.sh, try using this multiple times in a row or throughout the day on different days (if different phases of the Moon you’ll see more of a difference, of course).

NOTE: if it’s a Full Moon the script won’t look as nice.

Judges’ remarks:

Here is a nice compact program that changes with the phase of the Moon. Can you figure out how it does it?

The ANSI-C committee, among their multiple misdeeds, broke perfectly fun C programs by making it intractable for them to declare their own non-traditional prototype for main(). We have had to uglify this program in order to prevent C compilers from failing to compile it due to (the now changed) unusual arg types of the main() function.

Author’s remarks:

This program outputs a rough image of the moon in its current phase. The main obfuscation of this entry is its complicated double recursion (without any loop or conditional statement).

People living in the southern hemisphere may want to change acos(l/2) into acos(-l/2).

Primary files

• natori.c - entry source code
• Makefile - entry Makefile
• natori.alt.c - alternate source code
• natori.orig.c - original source code
• try.alt.sh - script to try alternate code
• try.sh - script to try entry

Secondary files

• 2000_natori.tar.bz2 - download entry tarball
• README.md - markdown source for this web page
• .entry.json - entry summary and manifest in JSON
• .gitignore - list of files that should not be committed under git
• .path - directory path from top level directory
• index.html - this web page

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