CIS 352   —   SPRING 2008

Homework 2

Coverage

Logistics

You may work singly or in pairs on this assignment.

What to Turn in:

• A copy of the source code and verified test cases demonstrating that your code is correct.
• Be sure to include contract and purpose statements for each procedure you are asked to write. (See the Homework Policy for more details.)

EXERCISES

1. (10 points) EOPL, Exercise 1.15(2)

2. (10 points) EOPL, Exercise 1.15(3)

3. (10 points) EOPL, Exercise 1.15(4)

4. (15 points) EOPL, Exercise 1.15(6)

5. (15 points) EOPL, Exercise 1.15(8)

6. (15 points) EOPL, Exercise 1.16(2)

7. (15 points) EOPL, Exercise 1.16(4)

8. (15 points) Write a Scheme procedure compose-all that takes an arbitrary number of 1-argument procedures and returns their composition. For example, compose-all should have the following behavior:

   > (define my-caddr (compose-all car cdr cdr)) 
   > (my-caddr '(a b c d e)) 
   c 
   
   > (define plus1 (lambda (x) (+ x 1))) 
   > (define times10 (lambda (y) (* y 10))) 
   > ((compose-all times10 times10 plus1 plus1) 3) 
   500
   
   > ((compose-all) 17) 
   17 

   Note: The result of composing 0 procedures is the identity procedure (i.e., the procedure that returns the value of its argument).