CSC 4101, Fall 2011
Due: 8 September 2011
1. (10 pts)
Draw binary tree diagrams for each of the following Scheme expressions:
(a)
’(a (b c) d e)
(b)
’((((a b) (c d)) e))
(c)
’(a (b (c (d (e f))) ()))
(d)
’(((()) ((()))))
(e)
’(((a b) c) d (((e f) g)))
2. (10 pts)
Show the result of evaluating each of the following Scheme expressions:
(a)
(cdr ’((a (b)) (c)))
(b)
(cons ’(a) ’((b) (c)))
(c)
(car (car (cdr ’(a ((b (c)))))))
(d)
(quote (car ’(a ((b) c))))
(e)
(car (quote (cons ’a ’((b) c))))
3. (10 pts)
Given the following Scheme deﬁnition:
(define x ’(define (fac n)
(if (= n 0) 1
(
*
n (fac ( n 1))))))
(This deﬁnes not the factorial function
fac
, but the variable
x
.)
Write Scheme expressions in terms of
x
that would have the effect of extracting the following expres
sions:
(a)
(fac n)
(b)
0
(c)
( n 1)
(d) The second occurrence of
fac
.
(e) The last occurrence of
n
.
E.g., the expression
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 Fall '08
 Kraft,D
 Atom, Recursion, CAR and CDR

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