Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!mit-eddie!rassilon
From: rassilon@eddie.MIT.EDU (Brian Preble)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Will Your SW Make it to the year 2000?
Message-ID: <12074@eddie.MIT.EDU>
Date: 26 Jun 89 04:29:43 GMT
References: <4342@druhi.ATT.COM> <972@ultb.UUCP>
Reply-To: rassilon@eddie.MIT.EDU (Brian Preble)
Organization: MIT, EE/CS Computer Facilities, Cambridge, MA
Lines: 30

In article <4342@druhi.ATT.COM> terrell@druhi.ATT.COM (TerrellE) writes:
>Will your software make it into the 21st century?  Does it cope with the
>Gregorian calendar reform of the 16th century?
>
>I was amused to find that allegedly state of the art scheduling software, 
>TimeLine, is broken for the year 2000.  So is MS DOS.
>
>The Gregorian calendar reform makes every year evenly divisible by 4 a
>leap year EXCEPT for century years.  Consequently there is no February 29,
>2000.

Slight correction, every year evenly divisible by 4 and not on a century
mark UNLESS evenly divisible by 400.  This means that February 29, 2000 is
valid, but February 29, 2100 is not.

The conditional code to determine if a given year is a leap year looks like
this:

In "C":
	((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)

In Pascal:
	((year MOD 4 = 0) AND (year MOD 100 <> 0)) OR (year MOD 400 == 0)

					Shar and Enjoy!

Rassilon (Brian Preble)
UUCP: ...!mit-eddie!rassilon
Internet: rassilon@eddie.mit.edu
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