Fundamentals of CS I (CS151 2002F)

Homework 8: Tail Recursion

Assigned: Friday, November 15, 2002
Due: Wednesday, November 20, 2002
No extensions!

Summary: In this assignment, you will consider a few of the more problematic issues in tail recursion.

Purposes: To give you more experience working with tail recursion and higher-order procedures.

Collaboration: Although you may certainly discuss this assignment with anyone, you should each turn in your own solution.


1. Consider the efficient exponent procedure we wrote in class. Rewrite that procedure to be tail recursive.

2. Rewrite insert-right to be tail recursive.

3. Here's a non-tail-recursive version of append.

(define append
  (lambda (list-one list-two)
    (if (null? list-one) list-two
        (cons (car list-one)
              (append (cdr list-one) list-two)))))

a. Write your own tail-recursive version.

b. Determine experimentally which of the three versions (built-in, given above, tail-recursive) is fastest.



Friday, 14 November 2002 [Samuel A. Rebelsky]


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Samuel A. Rebelsky,