william strutts wrote:
>Prodos has a date table which needs to be updated every seven years.
Actually, the table is seven entries long (indexed into by day of week),
but it can map only 5 or 6 years, depending on whether the range contains
one or two leap years.
Each leap year occupies two slots in the table. So if the first or second
year is a leap year, then the fifth (probably!) also is, and they consume four
slots, leaving only three other slots for the intervening non-leap years.
If the first is a leap year, then five full years will be mapped. If the
second
is a leap year, then five full years will be mapped plus part of the sixth
(the part before February 29).
If the first or second year is not a leap year, then only one leap year falls
in the range of the table, and five non-leap years can be accomodated for
a total of six years.
-michael
Email: mjmahon@aol.com
Home page: http://members.aol.com/MJMahon/