;;Akhila Ankem
;; 12/02/11
;; Structure Notes 2

;; A student is:
;; (make-student string string number string)
 (define-struct student (name grade teacher))

;; CONTSRUCTOR
;; make-student: string string number string -> student

;; SELECTOR
;; student-first: student -> string
;; student-last: student -> string
;; student-grade: student -> number
;; student-teacher: student -> string

;; PREDICATE
;; student?: any -> boolean

(define EMILY (make-student "Emily" "Stevens" 3 "Dominguez"))
(define MARIAH (make-student "Mariah" 1 "Wheeler"))
(define WES (make-student "Wesley" 5 "Stone"))

;; promote: student string-> student
;; Given a student and their new teacher, produces a student one grade higher
(define (promote a-student)
  (make-student (student-first a-student)
                (student-last a-student)
                (+ 1 (student-grade a-student))
                new-teacher))

(check-expect (promote EMILY "Johnson")
              (make-student "Emily" "Stevens" 3 "Johnson"))
(check-expect (promote SAMANTHA "Lightfoot")
              (make-student "Samantha" "Dearing" 3 "Lighthouse"))
(check-expect (promote KYLE "Adams")
              (mame-student "Kyle" "Smith" 3 "Adams"))

;; same-teacher?: student -> boolean
;; given two studnets, produces whether they have the same teacher.
(define (same-teacher? a-student b-student)
  (string=? (student-teacher a-student) (student-teacher b-student)
  (student-first a-student)
  (student-last a-student)
  (student-grade a-student)
  (student-teacher a-student))

(check-expect (same-teacher? KYLE EMILY) false)
(check-expect (same-teacher? SAMANTHA KYLE) false)
(check-expect (same-teacher? kyle (make-student "Mary" "Jones" 1 "Hunt")) true)