1 665c255d 2023-08-04 jrmu (define (test-case actual expected)
 2 665c255d 2023-08-04 jrmu   (newline)
 3 665c255d 2023-08-04 jrmu   (display "Actual:   ")
 4 665c255d 2023-08-04 jrmu   (display actual)
 5 665c255d 2023-08-04 jrmu   (newline)
 6 665c255d 2023-08-04 jrmu   (display "Expected: ")
 7 665c255d 2023-08-04 jrmu   (display expected)
 8 665c255d 2023-08-04 jrmu   (newline))
 9 665c255d 2023-08-04 jrmu 
10 665c255d 2023-08-04 jrmu (define (element-of-set? x set)
11 665c255d 2023-08-04 jrmu   (cond ((null? set) false)
12 665c255d 2023-08-04 jrmu 	((= x (car set)) true)
13 665c255d 2023-08-04 jrmu 	((< x (car set)) false)
14 665c255d 2023-08-04 jrmu 	(else (element-of-set? x (cdr set)))))
15 665c255d 2023-08-04 jrmu (define (intersection-set set1 set2)
16 665c255d 2023-08-04 jrmu   (if (or (null? set1) (null? set2))
17 665c255d 2023-08-04 jrmu       '()
18 665c255d 2023-08-04 jrmu       (let ((x1 (car set1)) (x2 (car set2)))
19 665c255d 2023-08-04 jrmu 	(cond ((= x1 x2) (cons x1 
20 665c255d 2023-08-04 jrmu 			       (intersection-set (cdr set1) 
21 665c255d 2023-08-04 jrmu 						 (cdr set2))))
22 665c255d 2023-08-04 jrmu 	      ((< x1 x2) (intersection-set (cdr set1)
23 665c255d 2023-08-04 jrmu 					   set2))
24 665c255d 2023-08-04 jrmu 	      ((> x1 x2) (intersection-set set1
25 665c255d 2023-08-04 jrmu 					   (cdr set2)))))))
26 665c255d 2023-08-04 jrmu 	      
27 665c255d 2023-08-04 jrmu ;; Exercise 2.61.  Give an implementation of adjoin-set using the ordered representation. By analogy with element-of-set? show how to take advantage of the ordering to produce a procedure that requires on the average about half as many steps as with the unordered representation. 
28 665c255d 2023-08-04 jrmu 
29 665c255d 2023-08-04 jrmu (define (adjoin-set x set)
30 665c255d 2023-08-04 jrmu   (cond ((null? set) (list x))
31 665c255d 2023-08-04 jrmu 	((= x (car set)) set)
32 665c255d 2023-08-04 jrmu 	((< x (car set)) (cons x set))
33 665c255d 2023-08-04 jrmu 	(else (cons (car set) (adjoin-set x (cdr set))))))
34 665c255d 2023-08-04 jrmu 
35 665c255d 2023-08-04 jrmu (test-case (adjoin-set 5 '()) '(5))
36 665c255d 2023-08-04 jrmu (test-case (adjoin-set 5 '(1 2 3 4 5)) '(1 2 3 4 5))
37 665c255d 2023-08-04 jrmu (test-case (adjoin-set 5 '(1 2 3 4)) '(1 2 3 4 5))
38 665c255d 2023-08-04 jrmu (test-case (adjoin-set 5 '(6 7 8 9)) '(5 6 7 8 9))
39 665c255d 2023-08-04 jrmu (test-case (adjoin-set 5 '(1 2 3 4 6 7 8 9)) '(1 2 3 4 5 6 7 8 9))
40 665c255d 2023-08-04 jrmu 	
41 665c255d 2023-08-04 jrmu  Exercise 2.62.  Give a (n) implementation of union-set for sets represented as ordered lists.