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 (last-pair x)
11 665c255d 2023-08-04 jrmu   (if (null? (cdr x))
12 665c255d 2023-08-04 jrmu       x
13 665c255d 2023-08-04 jrmu       (last-pair (cdr x))))
14 665c255d 2023-08-04 jrmu 
15 665c255d 2023-08-04 jrmu (define (make-cycle x)
16 665c255d 2023-08-04 jrmu   (set-cdr! (last-pair x) x)
17 665c255d 2023-08-04 jrmu   x)
18 665c255d 2023-08-04 jrmu 
19 665c255d 2023-08-04 jrmu Draw a box-and-pointer diagram that shows the structure z created by
20 665c255d 2023-08-04 jrmu 
21 665c255d 2023-08-04 jrmu (define z (make-cycle (list 'a 'b 'c)))
22 665c255d 2023-08-04 jrmu 
23 665c255d 2023-08-04 jrmu What happens if we try to compute (last-pair z)?