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;;;; License: CC0-1.0
#lang racket
(provide make-vect
xcor-vect
ycor-vect
add-vect
sub-vect
scale-vect)
(define (make-vect x y)
(cons x y))
(define (xcor-vect a)
(car a))
(define (ycor-vect a)
(cdr a))
(define (add-vect a b)
(let ((x (+ (xcor-vect a) (xcor-vect b)))
(y (+ (ycor-vect a) (ycor-vect b))))
(make-vect x y)))
(define (sub-vect a b)
(let ((x (- (xcor-vect a) (xcor-vect b)))
(y (- (ycor-vect a) (ycor-vect b))))
(make-vect x y)) )
(define (scale-vect s a)
(let ((x (* s (xcor-vect a)))
(y (* s (ycor-vect a))))
(make-vect x y)))
;;; Racket REPL
;;;
;;; 46.rkt> (define a (make-vect 8 16))
;;; 46.rkt> (define b (make-vect 32 64))
;;; 46.rkt> (xcor-vect a)
;;; 8
;;; 46.rkt> (ycor-vect a)
;;; 16
;;; 46.rkt> (add-vect a b)
;;; '(40 . 80)
;;; 46.rkt> (sub-vect b a)
;;; '(24 . 48)
;;; 46.rkt> (scale-vect 2 a)
;;; '(16 . 32)
;;; 46.rkt> (scale-vect 2 b)
;;; '(64 . 128)
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