;; The first three lines of this file were inserted by DrRacket. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-beginner-reader.ss" "lang")((modname 14.2.1) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ())))
(require picturing-programs)

; Exercises 14.2.1
(define WIDTH 500)
(define HEIGHT 100)
; Model: a number, increasing by 1 each second
; Tick handler: add1
; Draw handler show-num-at-x: number -> image
; written in exercise 10.2.5

; key-handler stop-on-key : number key -> number
(check-expect (stop-on-key 24 "whatever")
              (stop-with 24))
(define (stop-on-key model key) ; model number
  ; key	whatever this is (ignore)
  (stop-with model) )
(big-bang 0
          (check-with number?)
          (on-tick add1 1)
          (on-draw show-num-at-x) 
          (on-key stop-on-key))