From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f7be1,be6b7e036aa9236c X-Google-Attributes: gidf7be1,public X-Google-Thread: 11390f,be6b7e036aa9236c X-Google-Attributes: gid11390f,public X-Google-Thread: 103376,be6b7e036aa9236c X-Google-Attributes: gid103376,public X-Google-Thread: 1164ba,be6b7e036aa9236c X-Google-Attributes: gid1164ba,public X-Google-Thread: fa0ae,be6b7e036aa9236c X-Google-Attributes: gidfa0ae,public X-Google-Thread: 1094ba,be6b7e036aa9236c X-Google-Attributes: gid1094ba,public X-Google-Thread: 1014db,be6b7e036aa9236c X-Google-Attributes: gid1014db,public X-Google-Thread: 101deb,be6b7e036aa9236c X-Google-Attributes: gid101deb,public From: James Giles Subject: Re: language wars (results 13 September) last posting Date: 1996/09/18 Message-ID: <32409DAA.785C@cris.com>#1/1 X-Deja-AN: 181477391 distribution: inet references: <51bv60$8d@pheidippides.axion.bt.co.uk> to: Andrew Gierth content-type: text/plain; charset=us-ascii organization: Ricercar Software mime-version: 1.0 newsgroups: comp.lang.ada,comp.lang.apl,comp.lang.basic,comp.lang.c,comp.lang.fortran,comp.lang.perl.misc,comp.lang.pl1,comp.lang.rexx,comp.lang.pascal.misc,comp.lang.smalltalk x-mailer: Mozilla 3.0 (Win16; I) Date: 1996-09-18T00:00:00+00:00 List-Id: Andrew Gierth wrote: > [...] > However, 400 years is 4800 months, which is *not* divisible by 7. > Therefore it is manifestly impossible for a specified day-of-the-month > to fall equally on all days of the week. It so happens that the 13th > falls most often on Friday. The day of the week that the 13th of any month falls upon is entirely dependent on the day of the week the first of that year falls upon and on whether the year is a leap year or not. It does not depend on whether the number of months is divisible by 12. > [...] > Skeptics are invited to write a program to do the calculation for > themselves. Assuming that *you* have done so, please have the courtesy to run it 2800 years and note that the 13th is equidistributed in weekdays. Then you can come back and apologise. You have to run it more than 400 years because you have to go through a complete cycle of exceptions to the century rule. J. Giles Ricercar Software