; Use the data definition of Transportation for these three steps.
; STEP 1: Write some data examples of Transportation.
; STEP 2: Write the template for functions which consume Transportation inputs.
; STEP 3: Use the design recipe and the template you just wrote to design the
;         programs described below.

(define-struct taxi( distance fair))
(define-struct bus( route distance fair))
(define-struct walk( distance))

; A Transportation is one of
; - (make-taxi Number Number)
; - (make-bus String Number Number)
; - (make-walk Number)


; Data Examples:
; WRITE THESE!

; Template:
; WRITE THIS!


; Program 1: total-cost
; Finds the cost for traveling a distance
; - Taxis cost 2 dollars to start, plus the fair times the distance
; - Buses cost the fair no matter what the distance is
; - Walking costs nothing if distance is under 8 miles, otherwise
;         it costs 1 dollar for a drink every 8 miles


; Program 2: total-time
; Finds the time to travel a distance
; - Taxis take the distance divided by 25mph
; - Buses take the distance divided by 10mph unless the route is
;           an "express" which takes distance divided by 15mph
; - Walking takes the distance divided by 5mph

; Program 3: cost-per-distance
; Finds the cost per unit of travel
; - Taxis, Buses, and Walking take the total-cost divided by the distance