2.17-2.18

 

;2.17
(define (last-pair l)
  (cond ((null? l) 0)
        ((null? (cdr l)) l)
        (else (last-pair (cdr l)))))
     
 
;2.18
;reverse items
(define (my-reverse iterms)
    (define (iter lis i)
      (if (= i (length iterms))
          lis
          (iter (cons (list-ref iterms i) lis) (+ i 1))))
    (iter '() 0))