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Typical questions related to Quiz 2 - TDDC60, 2006
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1) [4 points] You will get some exercises in form of structures you need to draw
graphically and graphical structures for which you need to write the
corresponding Scheme-expression. Examples: see figures 2.2 and 2.3 in
the course book.
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2) [3 points] Write a Scheme-procedure MAP2 with three parameters F, LIST-1 and
LIST-2. With the assumption that the two lists have the same length,
MAP2 computes a list whose Nth element is the result of applying F to
the Nth element of LIST-1 and Nth element of LIST-2. Like so:

  (map2 + '(1 2 3) '(6 7 8)) 
     => (7 9 11)
  (map2 cons '(1 2 3) '(6 7 8)) 
     => ((1 . 6) (2 . 7) (3 . 8))
  (map2 (lambda (x y) (+ x (* 2 y)))
        '(1 2 3)
        '(4 3 2))
     => (9 8 7)

You are not allowed to define in terms of MAP procedure which exists in
Scheme.
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3) [6 points] The following lists contain information about students and the courses
they take. The first list (students) contains information about
students (person-no, name, address), the second list (courses) lists
existing courses (course-code, course-name and credit-points) and the
third list indicates the courses selected by students and the grades
the students have obtained in the course. For example, in the latter,
the sublist (800202-2253 TDDB27 4) means that the student with person-no
800202-2253 has selected the course TDDB27 and got the grade 4.

(define students
   (list
     	'(800202-2253 (Erik Andersson) ((Tröskareg 15) (58330 Linköping)))
	'(790302-4472 (Lars Hansson) ((Bygdegatan 103) (58331 Linköping)))
	'(820101-1927 (Anna Thurée) ((Odalgatan 202) (58331 Linköping))
	'(...))))

(define courses
   (list
	'(TDDB27 Pram 4)
	'(TDDC60 Pram 5)
	'(TDDB38 Databasteknik 5)
	'(...)))

(define selections
    (list
	'(800202-2253 TDDB27 4)
	'(790302-4472 TDDB38 3)
	'(800202-2253 TDDB38 5)
	'(...)))

1) For the elements of each list write the necessary CONSTRUCTOR and
SELECTOR procedures.

2) Write a Scheme-procedure called WHICH-STUDENTS that takes a course
code as argument and returns a list that contains the names and
addresses of the students who have taken the course. Like so:

> (which-students 'TDDB38)
(((Erik Andersson) ((Tröskareg 15) (58330 Linköping)))
 ((Lars Hansson) ((Bygdegatan 103) (58331 Linköping))))
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Here are some more problems selected from the course book SICP.

Exercise 2.7 (SICP)
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Exercise 2.17 (SICP)
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Exercise 2.33 (SICP)
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Exercise 2.37 (SICP)
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Exercise 2.32 (SICP) - a bit tricky
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