Pastebin: econmonth.bc

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2017-04-11 01:17

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Illimité

 # bc script for showing the lengths of the months relative to skip years
 # for the world of Bobbie, Karel, Dan, and Kristie, 
 #
 # by Joel Matthew Rees, winter/spring 2017.
 # Copyright 2017, Joel Matthew Rees
 #
 # Permission granted to use for personal entertainment only.
 # (If you need it for other purposes, rewriting it yourself is not that hard, 
 # and the result will satisfy your needs much more effectively.)
 #
 # See these chapters of Sociology 500, a Novel, on line: 
 # <http://joel-rees-economics.blogspot.com/2017/03/soc500-03-08-calendar-math.html> 
 # <http://joel-rees-economics.blogspot.jp/2017/04/soc500-03-09-calculating-months-skip-years.html> 
 # <http://joel-rees-economics.blogspot.com/2017/04/soc500-03-10-computers.html> 
 
 # Novel table of contents and preface here: 
 # <http://joel-rees-economics.blogspot.com/2017/01/soc500-00-00-toc.html>. 
 #
 # Save as "econmonth.bc"
 # invoke as "bc -l econmonth.bc
 #
 # In the running bc session, run it with
 # showmonths(7) for seven years, etc.
  
 
 scale = 10;
 
 
 months[ 0 ] = 30;
 months[ 1 ] = 29;
 months[ 2 ] = 30;
 months[ 3 ] = 29;
 months[ 4 ] = 29;
 months[ 5 ] = 30;
 months[ 6 ] = 29;
 months[ 7 ] = 30;
 months[ 8 ] = 29;
 months[ 9 ] = 29;
 months[ 10 ] = 30;
 months[ 11 ] = 29;
 
 define abs( n ) {
   if ( n >= 0 ) {
     return n;
   }
   return -n;
 }
 
 
 # If you want to do something similar, 
 # for looking at how leap years in your world  
 # match the actual orbits and revolutions
 # of your world and its moon,
 # replace isskip() with an appropriate isleap().
 # Left as an exercise for the reader.
 
 define isskip( y, m ) {
   if ( m != 0 ) {
     return 0;
   }
   mem = scale;
   scale = 0;
   diff7 = y % 7;
   diff98 = y % 98;
   diff343 = y % 343;
   scale = mem;
   if ( diff98 == 48 ) {
     return 1;
   }
   if ( ( diff7 != 1 ) && ( diff7 != 4 ) ) {
     return 0;
   }
   if ( diff343 == 186 ) {
     return 0;
   }
   return 1;
 }
 
 
 # Note that we are treating the first year as year 0, 
 # and the first month as month 0.
 # For your earth, you will need to adjust the year and month input and output.
 
 
 define showmonths( years ) {
   sum = 0;
   for ( year = 0; year < years; ++year ) {
     for ( month = 0; month <= 11; ++month ) {
       days = months[ month ];
       if ( isskip( year, month ) ) {
         days -= 1;
       }
       sum += days;
       product = year * ( 241957 / 686 ) + ( month + 1 ) * ( 241957 / 686 ) / 12;
       diff = product - sum;
       print year, " ", month, ": ", days, " (", sum , ", ", product, ": ", diff, ")";
       if ( abs( diff ) >= 1 ) {
         print "*** > 1 day! ";
       }
       print "\n";
     }
   }
 }
 
 
 # To show just the ideal months, run this:
 # showidealmonths(7) for seven years, etc.
  
 define showidealmonths( years ) {
   sum = 0;
   for ( year = 0; year < years; ++year ) {
     for ( month = 0; month < 12; ++month ) {
       days = 29;
       sum += days;
       product = year * ( 241957 / 686 ) + ( month + 1 ) * ( 241957 / 686 ) / 12;
       if ( ( product - sum ) >= 0 ) {
         days += 1; sum += 1;
       }
       print year, " ", month, ": ", days, " (", sum , ", ", product, ")\n";
     }
   }
 }