将大问题拆分成小问题
3.1 电影院利润问题
;; profit : number -> number ;; to compute the profit as the difference between revenue and costs ;; at some given ticket-price (define (profit ticket-price) ...)
;; revenue : number -> number ;; to compute the revenue, given ticket-price (define (revenue ticket-price) ...) ;; cost : number -> number ;; to compute the costs, given ticket-price (define (cost ticket-price) ...) ;; attendees : number -> number ;; to compute the number of attendees, given ticket-price
(define (attendees ticket-price) ...)