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Use segments in Ex2.2

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Correl Roush 2014-06-29 19:34:31 -04:00
parent 4944d5ceec
commit 627767534f
1 changed files with 11 additions and 5 deletions
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2-1.org
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@ -113,11 +113,17 @@ layout: org
(define x-point car)
(define y-point cdr)
(define (midpoint-segment p1 p2)
(define make-segment cons)
(define start-segment car)
(define end-segment cdr)
(define (midpoint-segment segment)
(let ((p1 (start-segment segment))
(p2 (end-segment segment)))
(let ((average (lambda (x y) (/ (+ x y) 2))))
(make-point
(average (x-point p1) (x-point p2))
(average (y-point p1) (y-point p2)))))
(average (y-point p1) (y-point p2))))))
#+end_src
** Exercise 2.3:
Implement a representation for rectangles in a plane. (Hint: You