1 12687dd9 2023-08-04 jrmu ;; The first three lines of this file were inserted by DrScheme. They record metadata
 2 12687dd9 2023-08-04 jrmu ;; about the language level of this file in a form that our tools can easily process.
 3 12687dd9 2023-08-04 jrmu #reader(lib "htdp-intermediate-reader.ss" "lang")((modname 18.1.15) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp")))))
 4 12687dd9 2023-08-04 jrmu (define-struct ir (name price))
 5 12687dd9 2023-08-04 jrmu 
 6 12687dd9 2023-08-04 jrmu ;An inventory-record (ir) is a structure
 7 12687dd9 2023-08-04 jrmu ;(make-ir n p)
 8 12687dd9 2023-08-04 jrmu ;where n is a symbol and p is a number.
 9 12687dd9 2023-08-04 jrmu 
10 12687dd9 2023-08-04 jrmu ;; extract1 : inventory  ->  inventory
11 12687dd9 2023-08-04 jrmu ;; to create an inventory from an-inv for all
12 12687dd9 2023-08-04 jrmu ;; those items that cost less than $1
13 12687dd9 2023-08-04 jrmu (define (extract1 an-inv)
14 12687dd9 2023-08-04 jrmu   (cond
15 12687dd9 2023-08-04 jrmu     [(empty? an-inv) empty]
16 12687dd9 2023-08-04 jrmu     [else (cond
17 12687dd9 2023-08-04 jrmu 	    [(<= (ir-price (first an-inv)) 1.00)
18 12687dd9 2023-08-04 jrmu 	     (cons (first an-inv) (extract1 (rest an-inv)))]
19 12687dd9 2023-08-04 jrmu 	    [else (extract1 (rest an-inv))])]))