0.5.5 Julian Calendar Algorithms
Included here are several Julian day routines. The date_to_julian is a calculation that assigns (almost) any date a
single (large) integer. This integer cooresponds to the number of
days between a set starting date and the given date. The difference
between the Julian numbers of any two dates is exactly the number of
days between the respective dates. By performing modulo division on
the Julian number of a date you can easily determine on what
dayoftheweek it fell. A division of a date's Julian number by
seven with no remainder means that the date is a Sunday. A remainder
of six means that the day is a Saturday. Further, a date's validity
can be checked by converting it into a Julian number, converting the
resultant Julian number back into a calendar date, and comparing the
two.
