SICP 2.48
前に解いたような問題だな。相変わらず図形はなし。
(define make-vect cons) (define xcor-vect car) (define ycor-vect cdr) (define (add-vect v1 v2) (make-vect (+ (xcor-vect v1) (xcor-vect v2)) (+ (ycor-vect v1) (ycor-vect v2)))) (define make-segment cons) (define start-segment car) (define (end-segment s) (add-vect (start-segment s) (cdr s))) ; test (define s (make-segment (make-vect 1 2) (make-vect 5 7))) (start-segment s) (end-segment s)