$ scheme48
      > ,load ex2-sum-square-smaller-two.scm
      > 
      > (sum-of-square-smaller-two 1 2 3)
      5
      > (sum-of-square-smaller-two 1 2 -3)
      10
      > (sum-of-square-smaller-two 2 2 2)
      8
      > ,exit
      $ 
      

      $ scheme48
      > ,load ex3-cube-root.scm
      > (cube-root 1331)
      11.0
      > (cube-root 512)
      8.0
      > ,exit
      $  
      

      $ scheme48
      > ,load ex4-fun.scm
      > (fun-rec 12)
      504
      > (fun-ite 12)
      504
      > (fun-ite 101)
      4298817677507282099568640
      > (fun-rec 101)
      ^C                     <----------- take too much time, so abort
      interrupt: keyboard interrupt [command-level-event-handler]
                 keyboard
      1> ,exit
      $ 
      

      $ scheme48
      > ,load ex7-pair-int.scm
      > (define x (my-cons 2 -5))
      ; no values returned
      > x
      67228
      > (my-car x)
      2
      > (my-cdr x)
      -5
      > ,exit
      $ 
      

      $ scheme48
      > ,load ex8-qsort.scm
      > (partition 5 '(9 8 7 1 2 3 5 6 7 10))
      ((5 3 2 1) (10 7 6 7 8 9))
      > (partition 5 '())
      (() ())
      > (qsort '(9 8 7 1 2 3 5 6 7 10))
      (1 2 3 5 6 7 7 8 9 10)
      > ,exit
      $ 
      

            a
          / | \      ==> (a (b) (c) (d))
         b  c  d

            a
          / | \      ==> (a (b) (c (e)) (d (f) (g))) 
         b  c  d
            |  |\
            e  f g

      

      $ scheme48
      > ,load preorder.scm
      > (preorder '(a (b) (c (e)) (d (f) (g))))
      (a b c e d f g)
      > (preorder '(a))
      (a)
      > ,exit
      $ 
      

      $ scheme48
      > ,load ex9-enum-tuples.scm
      > (enum-tuples)
      ()
      > (enum-tuples '(a b c))
      ((a) (b) (c))
      > (enum-tuples '(1 2) '(hello ohio aloha))
      ((1 hello) (2 hello) (1 ohio) (2 ohio) (1 aloha) (2 aloha))
      > (enum-tuples '(1 2) '(11 22) '(999))
      ((1 11 999) (2 11 999) (1 22 999) (2 22 999))
      > ,exit
      $