[Coco] Julian Date

[Arthur Flexser]

One might also point out that the subject line is misleading, as the rule
you're talking about describes the present-day (since 1582) Gregorian
calendar, not the Julian one, as correctly alluded to by William.  The
Gregorian calendar modified the Julian one by introducing the rule that
made only every fourth century year a leap year, bringing the calendar year
into closer correspondence with the astronomical solar year so that seasons
stay in the same place from year to year, with only an occasional leap
second needed to keep it all in sync.

1 average year (Julian) = 365.25 days
1 average year (Gregorian) = 365.2425 days
1 solar year = 365.24217 days

Art

On Sun, May 21, 2017 at 1:26 AM, Gene Heskett <gheskett at shentel.net> wrote:

> On Saturday 20 May 2017 23:48:59 William Astle wrote:
>
> > On 2017-05-20 05:10 PM, Gene Heskett wrote:
> > > Basically if the year is divisible by 4 its a leap year UNLESS the
> > > date is divisible by 400 without a remainder, then it is not a leap
> > > year. 2000 was not a leap year. 2400 will not be a leap year.  The C
> > > manual uses the mod(year,4) or mod(year,400) to determine this IIRC.
> >
> > Lest this leave people with an inaccurate understanding of the
> > Gregorian calendar, I think I should mention that Gene doesn't quite
> > have this right.
> >
> > The actual rule is: A year is a leap year if it is divisible by 4 but
> > is not divisible by 100. Additionally, if the year is divisible by
> > 400, it is a leap year.
> >
> > Note that 2000 *was* a leap year. 1900 wasn't and 2100 will not be but
> > 2400 will be.
>
> Ya caught me out on that one, William. I don't even have to pull one of
> my copies of K&R (I have both) down to double check.  Can I blame it on
> oldtimers? At 82, the wet ram I am finding is not quite as photographic
> as it once was.
>
> Cheers, Gene Heskett
> --
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>
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