Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site sdcc3.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!sdcsvax!sdcc3!33500911 From: 33500911@sdcc3.UUCP (James Hayes) Newsgroups: net.sources Subject: Re: Algorithm wanted Message-ID: <2519@sdcc3.UUCP> Date: Tue, 4-Dec-84 22:39:08 EST Article-I.D.: sdcc3.2519 Posted: Tue Dec 4 22:39:08 1984 Date-Received: Thu, 6-Dec-84 05:15:58 EST References: <515@uwmacc.UUCP> Reply-To: 33500911@sdcc3.UUCP (James Hayes) Distribution: net Organization: U.C. San Diego, Academic Computer Center Lines: 28 Summary: > Does someone "out there" know of an algorithm (or can direct me >to a source) which will calculate the Day of the Week (e.g. Monday, >Tuesday, etc) based on the month, the day and the year? >It will be greatly appreciated.... > - Rob DeMillo > Madison Academic Computing Center Sorry Folks, it's in BASIC... X=INT(.6+1/M) : Y1=Y-X : M1=M+12*X : X=Y1/100 N4=INT(X/4) : N3=INT(X) : N2=INT((5*Y1)/4) : N1=INT(13*(M1+1)/5) X=N1+N2-N3+N4+D-1 FD=X-(7*INT(X/7)) On entry: Y=year (must be after 1752) D=day M=month On exit: FD will contain an integer from 0 to 6. 0=Sunday and 6=Saturday. (And as you might have guessed 1-5 fall in-between.) James Hayes {ucbvax,sdcsvax}!sdcc3!33500911 [SPEED ISN'T EVERYTHING. YOU HAVE TO BE CORRECT SOME OF THE TIME]