ex: do ex 2.46

1 files changed, 51 insertions, 0 deletions

diff --git a/ex/2/46.rkt b/ex/2/46.rkt
new file mode 100644
index 0000000..6f0e33a
--- /dev/null
+++ b/ex/2/46.rkt
@@ -0,0 +1,51 @@
+;;;; 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)