Use segments in Ex2.2

This commit is contained in:
Correl Roush 2014-06-29 19:34:31 -04:00
parent 4944d5ceec
commit 627767534f

10
2-1.org
View file

@ -113,11 +113,17 @@ layout: org
(define x-point car) (define x-point car)
(define y-point cdr) (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)))) (let ((average (lambda (x y) (/ (+ x y) 2))))
(make-point (make-point
(average (x-point p1) (x-point p2)) (average (x-point p1) (x-point p2))
(average (y-point p1) (y-point p2))))) (average (y-point p1) (y-point p2))))))
#+end_src #+end_src
** Exercise 2.3: ** Exercise 2.3:
Implement a representation for rectangles in a plane. (Hint: You Implement a representation for rectangles in a plane. (Hint: You