Re: Zeller's Algorithm

[Thomas Wolf <t_wolf@angelfire.com>]

paul.a.storm@lmco.com wrote:
> Help!
> 
> I am trying to find a Ada implementation of Zeller's algorithm that
> works!  I have found several on the web
> but none of them have worked right.
> 
> For example I tried this one from
> http://www.adapower.com/alg/zeller.html  Inputting June 19 2002 returns
> Wednesday, correct.  Inputting June 19 1999 produces Sunday, incorrect. 
> That's a Saturday. Inputting
> February 3, 2002 produces Friday, incorrect.  That's a Sunday.  What
> gives?
> 
> I have had similar weird results using other similar Ada Zeller versions
> I've found on the web.

You might try the Util.Calendar packages from my Util subsystem,
available at the URL

http://home.tiscalinet.ch/t_wolf/tw/ada95/util/

Util.Calendars.Universal.Day_Of_Week produces the correct results.
See the test driver in ./test/calendar_test.adb for some examples.

The Util subsystem is published under the GMGPL.

-- 
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Thomas Wolf                          e-mail: t_wolf@angelfire.com