date conversion

[colonel at sunybcs.UUCP]

Here's how Professor Fordney (remember him?) explained it to his class
in 1933.  (I've used this method since I read it!)

	To find the day of the week for any given date after 1752
	do the following:

1.	Take the last two figures of the year, add 1/4 of them,
	neglecting remainder.

2.	Add for month, if for January or October, the numeral 1;
	May, 2; August, 3; February, March or November, 4; June,
	5; September or December, 6; April or July, 0; if leap
	year [that is, if it is divisible by 4 without remainder]
	January 0, February 3.

3.	Add day of month.  Divide the sum of these three by 7 and
	remainder gives the number of the day of the week.  Thus:
	_What day of the week was August 28, 1911?_

[1] 11 + 2 = 13		\ 44 = 7 x 6 + 2 or second day of week =
			| Monday.  This applies only to the 20th
[2] August = 3		> century.  For 19th century, add 2; for
			| 21st century, add 6; 18th century, 4.
[3] Date = 28		/

		--H. A. Ripley, "Tough Tim's New Year's Eve Party,"
		  in _How Good A Detective Are You_ (Lippincott, 1934)
-- 
Col. G. L. Sicherman
UU: ...{rocksvax|decvax}!sunybcs!colonel
CS: colonel at buffalo-cs
BI: colonel at sunybcs, csdsiche at ubvms