Need time subtraction routine

[Lorien Y. Pratt]

I'm about to sit down to write a function to return a user-friendly
string that indicates the elapsed time between two times that are in
the format hh:mm:ss.  I can pass this routine the date and year, too,
if necessary.  If anyone has already written such a beast, I'd
appreciate it if you'd pass it along.

I'm running 4.2Bsd on an 11/750.  Yes, I know that if I use the system
built-in time functions, I wouldn't have to go through this hassle.
Unfortunately, I'm reading a transaction file that's pre-formatted with
times in an "easy to read" format instead of showing elapsed seconds
since the first day of 1970.

	Thanks for any time you can save me!

      --Lorien Y. Pratt
	Dartmouth College Library
	Hanover, NH  03755

	decvax!dartvax!lorien