Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!usc!orion.oac.uci.edu!uci-ics!zardoz!anacom1!jim
From: jim@anacom1.UUCP (Jim Bacon)
Newsgroups: comp.lang.c
Subject: Re: Computing Day of the Week
Keywords: given month and day
Message-ID: <365@anacom1.UUCP>
Date: 9 Dec 89 22:20:24 GMT
References: <1894@ntmtka.mn.org>
Reply-To: jim@anacom1.UUCP (Jim Bacon)
Distribution: usa
Organization: Anacom CPD, Anaheim, CA
Lines: 20

In article <1894@ntmtka.mn.org> mike@ntmtka.mn.org (Mike Tietel) writes:
>I know there exists an algorithm to compute the day of the week,
>given the month, day and year.  For example, what day of the week
>is September 13, 1998?
>
>Does anyone know where I can find the algorithm, or alternatively,
>where I can find its "C" implementation???
>
The book "Common C Functions" published by Que contains a very good
section on date manipulation routines including the Zeller congruence
routine you are looking for.  Source is given in C for the IBM PC, but
is portable with little or no change to UNIX.  The other routines are
for doing Julian conversions and date math.  I have found them to be
quite useful and have incorporated them into our local library.

-- 
Jim Bacon                            | "A computer's attention span is only
Anacom General Corp., CA             |  as long as its extension cord."
jim@anacom1.cpd.com                  |
zardoz!anacom1!jim                   |                                 Anon