eecs111_w16_exam1_practice.rkt

(define-struct circle [radius color])
; A Circle is a structure: (make-circle Number String)

(define circ1 (make-circle 4 "blue"))
(define circ2 (make-circle 2 "red"))

; -----------------------------------------------------

(define-struct square [side color])
; A Square is a structure: (make-square Number String)
; For purposes of this exercise, a square is not a rectangle

(define sq1 (make-square 4 "blue"))
(define sq2 (make-square 10 "green"))

; -----------------------------------------------------

(define-struct rectangle [length width color])
; A Rectangle is a structure: (make-rectangle Number Number String)
; where length and width are different
; because for purposes of this exercise, a rectangle is not a square

(define rect1 (make-rectangle 3 4 "blue"))
(define rect2 (make-rectangle 6 10 "red"))

; -----------------------------------------------------

; Exercise 1a
; circle-is-blue? : Circle -> Boolean
; returns true if a Circle has color "blue," false otherwise
(check-expect (circle-is-blue? circ1) true)
(check-expect (circle-is-blue? circ2) false)

(define (circle-is-blue? c)
  (eq? "blue" (circle-color c)))

; -----------------------------------------------------

; A Shape is one of the following:
; - A Circle
; - A Square
; - A Rectangle

; -----------------------------------------------------

; Exercise 1b
; shape-is-blue? : Shape -> Boolean
; returns true if a Shape has color "blue", false otherwise
(check-expect (shape-is-blue? circ1) true)
(check-expect (shape-is-blue? sq1) true)
(check-expect (shape-is-blue? rect2) false)

(define (shape-is-blue? s)
  (cond
    [(circle? s) (eq? "blue" (circle-color s))]
    [(square? s) (eq? "blue" (square-color s))]
    [(rectangle? s) (eq? "blue" (rectangle-color s))]))

; -----------------------------------------------------

; A List-of-Shapes is one of the following:
; - empty
; - (cons Shape List-of-Shapes)

(define my-shape-list (list circ2 sq2 rect1 circ1 rect2 sq1))

; generally speaking, we won't bother creating a nickname for an empty list
; since we can just test functions by typing the word 'empty' itself
; this is just to demonstrate that empty is a valid example of a List-of-Shapes
; according to our definition above
(define empty-shape-list empty)

; -----------------------------------------------------

; Exercise 1c
; first-blue-shape? : List-of-Shapes -> Shape or Boolean
; returns the first Shape in the list with color "blue"
; if there are no Shapes with color "blue", return false
(check-expect (first-blue-shape? my-shape-list) rect1)
(check-expect (first-blue-shape? empty) false)

(define (first-blue-shape? los)
  (cond
    [(empty? los) false]
    [(eq? "blue"
          (cond
            [(circle? (first los)) (circle-color (first los))]
            [(square? (first los)) (square-color (first los))]
            [(rectangle? (first los)) (rectangle-color (first los))]))
     (first los)]
    [else (first-blue-shape? (rest los))]))

; Exercise 1d
; first-blue-shape-helper : List-of-Shapes -> Shape or Boolean
; this time, use at least one helper function (it can do anything)

; Exercise 1e
; first-blue-shape-message : List-of-Shapes -> String
; rewrite first-blue-shape? but instead of returning the first matching Shape
; we return the string "Found a blue shape!"
; if there are no Shapes with color "blue", return "No blue shapes"

; now create a list of non-blue shapes
; and write tests for these

; I stopped numbering exercises because I'm lazy........

; -----------------------------------------------------

; square-area : Square -> Number
; return the area of the provided Square

; write your tests here

; write your function here


; rectangle-area : Rectangle -> Number
; return the area of the provided Rectangle

; write your tests here

; write your function here


; circle-area : Circle -> Number
; return the area of the provided Circle

; FYI, Racket recognizes pi as a number
; Another FYI, use pi in your check-expects to avoid annoying decimal mismatches

; write your tests here

; write your function here


; -----------------------------------------------------

; shape-area : Shape -> Number
; return the area of the provided Shape
; USING THE THREE FUNCTIONS YOU WROTE IN THE PREVIOUS SECTION

; -----------------------------------------------------

; sum-shape-area : List-of-Shapes -> Number
; return the sum of the areas of the Shapes in the provided List
; USE YOUR PREVIOUSLY WRITTEN HELPER FUNCTIONS

; NOW WRITE
; sum-shape-area-no-helpers : List-of-Shapes -> Number
; return the sum of the areas of the Shapes in the provided list
; YOU CAN'T USE ANY HELPER FUNCTIONS
; BUT YOU *CAN* COPY AND PASTE CODE FROM OLDER FUNCTIONS

; sorry i just started shouting for no reason

; -----------------------------------------------------

; now define three more Lists-of-Shapes for our tests
; the first two lists should contain at least one blue shape
; the third list should not contain any blue shapes

; contains-blue-shape? : List-of-Shapes -> Boolean
; true if the List of Shapes contains a blue shape, false otherwise
; Hint: this will be very similar to an older function

; -----------------------------------------------------

; blue-in-both? : List-of-Shapes List-of-Shapes -> Boolean
; given two Lists-of-Shapes, return true if both lists contain at least one blue shape

; -----------------------------------------------------

; Super challenge question, whoo
; write the following program

; A Color is one of the following:
; - "red"
; - "blue"
; - "green"

; match-in-both? : List-of-Shapes List-of-Shapes Color -> Boolean
; given two Lists-of-Shapes and a Color, return true if both lists contain
; at least one shape matching the provided Color