#lang racket
(require rackunit)

; OPENING EXERCISE -----------------------------------------------------

(define student-grade (/ 248 285))
; (exact->inexact student-grade)

; writing letter-grade-for with an if expression

(define letter-grade-for
  (lambda (value)
    'Z                  ;; FILL IN THE BLANK
  ))

; writing letter-grade-for with a cond expression
;
; (define letter-grade-for
;   (lambda (value)
;     (cond ((>= value 0.90) 'A)
;           ((>= value 0.80) 'B)
;           ((>= value 0.70) 'C)
;           ((>= value 0.60) 'D)
;           (else 'F))))

; tests from the session notes
(check-equal? (letter-grade-for student-grade) 'B)
(check-equal? (letter-grade-for 0.95)          'A)
(check-equal? (letter-grade-for 0.77)          'C)

; Racket also has a case expression that matches exact items
;
; (case (random 6)
;   ((0)     'zero)
;   ((1)     'one)
;   ((2 3 4) 'few)
;   (else    'many))

; THE END --------------------------------------------------------------

; code I can copy and paste into the function above...
;
;    (if (>= value 0.90)
;        'A
;        (if (>= value 0.80)
;            'B
;            (if (>= value 0.70)
;                'C
;                (if (>= value 0.60)
;                    'D
;                    'F))))

; REALLY THE END -------------------------------------------------------