CSC151.02 2016S, Class 17: Boolean Values and Predicate Procedures ================================================================== _Overview_ * Preliminaries. * Admin. * Upcoming Work. * Extra Credit. * Questions. * Numbers vs. Images. * Testing. * Lab. Preliminaries ------------- ### Admin * New partners! * Sam is incredibly behind on grading. Quizzes returned tomorrow. Exams may take another week. * If you invoked "There's more to life", wait until you get your exam back to meet with me. * We'll talk a little bit about testing. ### Reminders * Office hours: MTWF 10-11, Tu 1-2. * Sign up at . * Also feel free to stop by when my door is open. * Or to email me for an appointment. * Tutor hours * Sunday, 3-5 p.m. * Sunday-Thursday, 7-10 p.m. * Weekly review sessions: * Wednesday at 8pm in the CS Commons with #Sorry Sarah * Thursday at 10am in this room with #Sorrier SamR * Thursday at 8pm in the CS Commons with #Apologetic Alex ### Upcoming Work: * Reading for Tuesday * [Conditionals](../readings/conditionals-reading.html) * [Assignment 4](../assignments/assignment.04.html) due Tuesday night at 10:30 p.m. * Lab Writeup: Exercise 1c. * Send email titled __CSC 151 Lab Writeup 17 (Your Names)__ * Do not include the underscores. * Send to * Due before class on Wednesday. ### Extra Credit * Send your reports to with subject "CSC 151 Extra Credit". * Send opportunities to me before class with subject "CSC 151 EXTRA CREDIT OPPORTUNITY!" #### Academic * Sexual Assault Awareness Week Discussion, Monday, 7:30 pm JRC 101 * CS Table, Noon, Tuesday, White PDR. * State of SHACS Discussion, Tuesday, 7pm JRC 209 * Town Hall, Wednesday, noon or 7:30 pm (I think) JRC 101 #### Peer * Pun Club Tournament Friday the 26th in the evening (Bobs). * Contra Dance Friday the 26th in the evening (Main). * Improv Show the 27th in the evening in Loose Lounge (7:30). * Vote for SGA positions. * Go to Wednesday's SGA meeting to make noise about the reserve. * AppDev Pub Night, Friday, 8pm, Lyle's (JRC Basement). * Black History Month Showcase, Friday, Harris, 7:30 p.m. #### Regular Peer * Social Dance Workshop Tuesdays 7:00-8:00 in Bucksbaum Dance Studio * Pun club Saturdays at 4pm in Younker (max 2) * Electronic Potpourri on KDIC Fridays at Five (TONIGHT) * Space Odyssey KDIC Fridays at Six ### No Extra Credit, But Still Good ### Questions Numbers vs. Images ------------------ * Images are misleading. * Numbers are telling. Testing ------- We'll work on some simple tests for `smaller-neighbor`. * Goal of smaller neighbor: Make a copy of the same drawing, right next to it, but smaller. * "Right next to each other" = "The borders are touching" = "The right of the orignal = the left of the neighbor" = `(drawing-right original) = (drawing-left neighbor)`. * Same shape. * Same color. * Proportionally smaller width and height (3/4 as big) * Top should be the same As a procedure. 
(define check-right-neighbor
  (lambda (drawing neighbor)
    (check-= (drawing-right drawing)
             (drawing-left neighbor)
             .00001
             "next to each other")
    (check-= (drawing-top drawing)
             (drawing-top neighbor)
             .00001
             "tops aligned")
    (check-equal? (drawing-color drawing)
                  (drawing-color neighbor)
                  "same colors")
    (check-equal? (drawing-type drawing)
                  (drawing-type neighbor)
                  "same shape")
    (check-= (* 3/4 (drawing-width drawing))
             (drawing-width neighbor)
             .00001
             "proportional width")
    (check-= (* 3/4 (drawing-height drawing))
             (drawing-height neighbor)
             .00001
             "proportional height")))
Here's what we saw (more or less). 
Welcome to DrRacket, version 6.1 [3m].
Language: racket [custom]; memory limit: 128 MB.
; Manually build a rectangle and its neighbor
> (define rect1 (rectangle "red" 50 30 20 20))
> (define rect2 (rectangle "red" 65 30 15 15))
> (check-right-neighbor rect1 rect2)
--------------------
FAILURE
name:       check-=
location:   (#<path:/home/rebelsky/Desktop/class17.rkt> 109 4 3110 124)
expression: (check-= (drawing-right drawing) (drawing-left neighbor) 1e-05)
params:     (70 65 1e-05)
message:    "next to each other"

. . Check failure
--------------------
; Okay, the left edge of rect2 was in the wrong place.  Fix it.
> (define rect2 (rectangle "red" 70 30 15 15))
> (check-right-neighbor rect1 rect2)
; Now we get no errors.  What happens if we recolor?
> (define rect2 (rectangle "grey" 70 30 15 15))
> (check-right-neighbor rect1 rect2)
--------------------
FAILURE
actual:     16711680
expected:   8421504
name:       check-equal?
location:   (#<path:/home/rebelsky/Desktop/class17.rkt> 117 4 3359 113)
expression: (check-equal? (drawing-color drawing) (drawing-color neighbor))
message:    "same colors"

. . Check failure
--------------------
; As expected, it tells us that the colors are not the same.
; Let's check the wrong shape.
> (define rect2 (ellipse "red" 70 30 15 15))
> (check-right-neighbor rect1 rect2)
--------------------
FAILURE
actual:     rectangle
expected:   ellipse
name:       check-equal?
location:   (#<path:/home/rebelsky/Desktop/class17.rkt> 120 4 3477 110)
expression: (check-equal? (drawing-type drawing) (drawing-type neighbor))
message:    "same shape"

. . Check failure
--------------------
; Now, let's see whether our smaller-neighbor procedure works.
> (check-right-neighbor rect1 (smaller-neighbor rect1))
--------------------
FAILURE
name:       check-=
location:   (#<path:/home/rebelsky/Desktop/class17.rkt> 109 4 3110 124)
expression: (check-= (drawing-right drawing) (drawing-left neighbor) 1e-05)
params:     (70 115/2 1e-05)
message:    "next to each other"

. . Check failure
--------------------
--------------------
FAILURE
name:       check-=
location:   (#<path:/home/rebelsky/Desktop/class17.rkt> 113 4 3239 115)
expression: (check-= (drawing-top drawing) (drawing-top neighbor) 1e-05)
params:     (30 45/2 1e-05)
message:    "tops aligned"

. . Check failure
--------------------
; Two failures!  The right and left edges don't match (way off) and
; the tops don't match (also off).
Lab --- Writeup: 1c.