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From: hallett@shoreland.uucp (Jeff Hallett x4-6328)
Newsgroups: comp.sys.mac
Subject: Week DAYS (was Re: why 1904?  ms excel)
Message-ID: <972@mrsvr.UUCP>
Date: 7 Sep 89 14:12:35 GMT
References: <457a7553.1285f@maize.engin.umich.edu> <8909061947.AA00416@vs04csc.UMD.EDU>
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Reply-To: hallett@shoreland.UUCP (Jeff Hallett x4-6328)
Organization: GE Medical Systems, Milwaukee,  WI
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In article <8909061947.AA00416@vs04csc.UMD.EDU> russotto@wam.UMD.EDU writes:
>The easy answer is that the Mac OS does it from 1904.  The deeper reason
>for it, though, is that there is an easier leap year rule for dates
>starting in 1904 and going to a date < 2100.  That is, for those
>dates, a leap year is any year divisible by 4.  If you include 1900,
>a leap year is any year divisible by four that is either not divisible
>by 100, or is divisible by 400.

Interesting.  One thing I've always wondered about, though, is, given
a date in the Gregorian calendar, how does one determine the day of
the week?  There is obviously a brute force approach, but does someone
know (and will relate) an elegant solution?

Thanks

--
                Jeffrey A. Hallett, PET Software Engineering
                    GE Medical Systems, W641, PO Box 414
                            Milwaukee, WI  53201
          (414) 548-5163 : EMAIL -  hallett@positron.gemed.ge.com