Write a generalized fast-expt run in linear iterative way.
That is, the operation and the unit element of that operation are the arguments.
Refer to exercise 1.16, 1.17 and section 1.3 in the textbook.
Deadline: 2010 Apr 7 00:05am
Put your file(s) under ~/scheme-982/exer5

for example:

$ scheme48
Welcome to Scheme 48 1.8 (made by klim on Tue Feb 17 11:32:15 CST 2009)
Copyright (c) 1993-2008 by Richard Kelsey and Jonathan Rees.
Please report bugs to scheme-48-bugs@s48.org.
Get more information at http://www.s48.org/.
Type ,? (comma question-mark) for help.
> ,load exer5.scm
> (fast 2 * 10 1)
1024
> (fast 5 + 10 0)
50
> ,exit
$