Devin Asay wrote:
I am working on a scheduling program that includes the ability to
schedule an event every other week over a specific time period. To
determine whether the event should occur during any given week during
the time period I do some simple date math to figure out whether a
multiple of 14 days have passed since the first occurrence of the
event. Let's say I've scheduled an event for every other week on Friday,
beginning January 11, 2008 and ending April 11, 2008. For any given week
on my calendar I can calculate whether the event should show up using
this algorithm (pseudocode):
get the date of the first occurrence of the event and convert it to seconds
get the date of that the event should fall on if this week falls in the
every-other-week pattern, convert it to seconds
subtract date 2 from date 1
divide the difference by (60*60*24*14) --the number of seconds in 14 days
if the difference divides evenly (modulo division = 0) then the event
should occur in the week in question
This works fine for a few weeks, but then inexplicably fails. For
example, Jan. 11, Jan. 25, Feb. 8, Feb. 22, and March 7 all show the
event properly. But anything after that fails; i.e., March 21, April 4.
I'm not sure why it would fail; that one hour difference is suspiciously
like a time zone error or a daylight savings time error (which would
still be a bug, if that's what's happening.)
But changing the calculation to use dateitems seems to work okay (and
avoids all those inscrutable big numbers):
put "1/11/08" into tDate
put "4/15/08" into tStopDate
convert tStopDate to seconds
repeat
convert tDate to dateitems
add 14 to item 3 of tDate
convert tDate to seconds
if tDate > tStopDate then exit repeat
convert tDate to short date -- if you need that
put cr & tDate after fld 1 -- or fill your calendar field here
end repeat
--
Jacqueline Landman Gay | [EMAIL PROTECTED]
HyperActive Software | http://www.hyperactivesw.com
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