RE: the seed date behind the curtain--RE: Can I get the Day of the we ek?

...then my instructor was wrong...

-----Original Message-----
From: Joel Fritz [mailto:JFritz@sharperimage.com]
Sent: Wednesday, May 16, 2001 11:28 AM
To: 'RPG400-L@midrange.com'
Subject: the seed date behind the curtain--RE: Can I get the Day of the
we ek?


The following link describes Zeller's Congruence--the formula below--which
uses the date England adopted the Gregorian calendar as its seed.  The
sample problem on the web page assumes that the college is solvent.   

http://www.cs.unt.edu/~acm/hspc/samples/beg-P1.html



> -----Original Message-----
> From: Wills, Mike N. (TC) [mailto:MNWills@taylorcorp.com]
> Sent: Wednesday, May 16, 2001 7:41 AM
> To: 'RPG400-L@midrange.com'
> Subject: RE: Can I get the Day of the week?
> 
> 
> There is a mathematical formula for getting the day of the week:
> 
> D = Day
> M = Month
> Y = the last two digits of the year
> C = Century
> 
> ((d + y) - (2 * c) + (y / 4) + (c / 4) + ((13 * m - 1) / 5)) % 7 = Day
> 
> For the Day: 0 = Sunday, 1 = Monday, etc.
> For some reason my program is a day off right now but I am 
> positive I had it
> working before. I haven't taken the time to debug it yet. 
> This was done in
> C++ on a PC. I need to double check my formula.
> 
> But with this formula it doesn't depend on a known date. I 
> don't know if it
> could cause problems, I just remember people keep on saying 
> to NOT hard-code
> anything in if possible (although I am sure many of us do 
> anyway). This is a
> formula that my instructor gave me and I have seen it on the 
> web. Then, if
> you (for some weird reason) need a day from the 1600's you 
> can get it. 
> 
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