Date arithmetic in C-Shell scripts?

[John O'Brien]

Is there some way to do date arithmetic in C-Shell scripts?
For instance, is it possible to get the date for next Monday
as a string?  Is it possible to say "give me the date of the
day 113 days from today"?  Or do I have to write a C program
to do Zeller's Congruence or something like that?  Does any-
one out there have an algorithm for calculating Easter for a
given year (I don't need this, but someone told me it's a very
interesting algorithm)

	(National) Enquiring Minds Want to Know!

"Now, let me get this straight.  In Sept. 1752, 2+1=14.  Is
there something it's missing?"