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POBash Version of C64 Code Art: 10 PRINT CHR$(205.5+RND(1)); : GOTO 10
 

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  1. POBash Version of C64 Code Art: 10 PRINT CHR$(205.5+RND(1)); : GOTO 10
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    <p>I picked up a copy of the book <strong>10 PRINT CHR$(205.5+RND(1)); : GOTO 10</strong></p> <ul> <li><a href="http://rads.stackoverflow.com/amzn/click/0262018462" rel="nofollow">http://www.amazon.com/10-PRINT-CHR-205-5-RND/dp/0262018462</a></li> </ul> <p>This book discusses the art produced by the single line of Commodore 64 BASIC:</p> <pre><code>10 PRINT CHR$(205.5+RND(1)); : GOTO 10 </code></pre> <hr> <p>This just repeatedly prints randomly character 205 or 206 to the screen from the PETSCII set:</p> <ul> <li><a href="http://en.wikipedia.org/wiki/PETSCII" rel="nofollow">http://en.wikipedia.org/wiki/PETSCII</a></li> <li><a href="https://vimeo.com/26472518" rel="nofollow">https://vimeo.com/26472518</a></li> </ul> <p>I'm not sure why the original uses the characters 205 and 206 instead of the identical 109 and 110. Also, I prefer to add a clear at the beginning. This is what I usually type into the C64:</p> <pre><code>1?CHR$(147) 2?CHR$(109.5+RND(1));:GOTO2 RUN </code></pre> <p>You can try this all for yourself in an emulator, such as this one using Flash or JavaScript:</p> <ul> <li><a href="http://codeazur.com.br/stuff/fc64_final/" rel="nofollow">http://codeazur.com.br/stuff/fc64_final/</a></li> <li><p><a href="http://www.kingsquare.nl/jsc64" rel="nofollow">http://www.kingsquare.nl/jsc64</a></p> <p>When inputting the above code into the emulators listed, you'll need to realize that </p> <ul> <li>( is *</li> <li>) is (</li> <li>+ is ]</li> </ul></li> </ul> <hr> <p>I decided it would be amusing to write a bash line to do something similar.</p> <p>I currently have:</p> <pre><code>clear; while :; do [ $(($RANDOM%2)) -eq 0 ] &amp;&amp; (printf "\\") || (printf "/"); done; </code></pre> <p>Two questions:</p> <ol> <li>Any suggestions for making this more concise? </li> <li>Any suggestions for a better output character? The forward and backward slash are not nearly as beautiful since their points don't line up. The characters used from PETSCII are special characters, not slashes. I didn't see anything in ASCII that could work as well, but maybe you can suggest a way to pull in a character from UTF-8 or something else?</li> </ol> <hr> <p><strong>Best ANSWERS So Far</strong></p> <p>Shortest for bash (40 characters):</p> <pre><code>yes 'c=(╱ ╲);printf ${c[RANDOM%2]}'|bash </code></pre> <p>Here is a short one for zsh (53 characters):</p> <pre><code>c=(╱ ╲);clear;while :;do printf ${c[RANDOM%2+1]};done </code></pre> <p>Here is an alias I like to put in my .bashrc or .profile</p> <pre><code>alias art='c=(╱ ╲);while :;do printf "%s" ${c[RANDOM%2]};done' </code></pre> <p>Funny comparing this to the shortest I can do for C64 BASIC (23 characters):</p> <pre><code>1?C_(109.5+R_(1));:G_1 </code></pre> <p>The underscores are shift+H, shift+N, and shift+O respectively. I can't paste the character here since they are specific to PETSCII. Also, the C64 output looks prettier ;)</p> <p>You can read about the C64 BASIC abbreviations here:</p> <ul> <li><a href="http://www.commodore.ca/manuals/c64_programmers_reference/c64-programmers_reference_guide-02-basic_language_vocabulary.pdf" rel="nofollow">http://www.commodore.ca/manuals/c64_programmers_reference/c64-programmers_reference_guide-02-basic_language_vocabulary.pdf</a></li> </ul>
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    1. COYou might be also interested in [Random maze generator](http://www.perlmonks.org/?node_id=843144). It removes all unaccessible rooms larger than 1 after generating the maze. A [screencast](http://www.youtube.com/watch?v=HqyeksHSoRo) is available, too.
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    2. CO@choroba: That's really great, thank you! I will certainly be playing with that.
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    3. COOne of your ancillary questions: "why 205 and 206 instead of 109 and 110?" The book addresses this in depth. Quick answer is that that is how the program was published at the time (circa 1982). The authors speculate on page 226: "A likely explanation can be found in the way the Commodore 64 responds to PRINT ASC("X")..." "[a user] could type PRINT ASC("/") and the computer would respond with "206." Not really your main question but couldn't resist answering :)
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      1. USSteve Koch
 

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