CompSci 94 Fall 2022 Exam 3 Solutions

1. While loop Iteration

1) 7
2) 3
3) Line 01 is creating and initializing the variable someValue
Line 06 is updating or changing the value of the variable someValue

2. Array index problems
A) 5 pts - 2, 2, 1 pts   B) 5 pts)     C) 4 pts

Part A)
One at a time, the objects in the creatures array turn around once. They
turn around in the order they appear in the creatures array:
bear, camel, cow, elk, horse, and then wolf.

Then at the same time, all the objects in the creatures array say "hello"

Then cow says "restaurant"

Part B)
The camel says "museum"
The cow says "movie"
The elk says "restaurant"
The horse says "zoo"

Part C)
Explanation:
The problem with the code is the indexOne updates only when a word starts with
"m". For any other word indexOne never updates so it gets stuck in an
infinite loop.

To FIX:
the line indexOne <- indexOne + 1 should be moved to immediately after
the if statement.
OR
Add indexOne <- indexOne + 1
right after the cow says the word in the words array as part of the
True part of the if.

Problem 3) 

A) Quadruped

B) The elk says "cheers"

C) The camel says "hello"

D) The bear says "goodbye"

E) The mystery procedure returns the first animal in the array creatures
that is less than 1.5 units from the animal passed in. If no such creatures
in the array are within 1.5 units from the animal, it returns the 
first animal in the array. 

Problem 4

A) Nothing

B) Mad Hatter turn around once

C) The Mad Hatter moves up and down once

D) The whiteRabbit says I'm late

Problem 5

A) The bunny turns right once, the bunny says "lunch"
and then the pig moves backwards once

B) The panda says "hello", the bunny says "lunch", and
the hare moves up and down.

C) The panda says "hello", the bunny says "lunch" and
the pig moves backwards

D) nothing happens

Problem 6

When the run button is pressed:

At the same time, the hare moves forward one unit and the tortoise moves to
its left one unit.
Then the bunny moves back one unit (since the tortoise collided with it)
Then the pig moves to its right one unit (since the bunny collided with it)

Problem 7
2 pts and 4 pts

Part A)

When the run button is pressed...

The bunny moves right one unit and then
the tortoise moves to its right one unit (due to the collision with the
bunny)

Part B)

If the H key is pressed, the hare turns around once

If the R key is pressed, the pig moves to its right. If the pig
collides with the hare, the hare moves backward one unit.

If any key other than H or R is pressed, the tortoise moves left one unit.

The tortoise could collide with the bunny and if that happens, the tortoise
moves to the right one.

Problem 8

A) 3  B) 3  C) 4  D) 4
Part A)

The score is initialized to 0 and displayed as 0.

Part B)

Add a WholeNumber parameter named amount.

Change the 1 in the first line to add amount to the score as:

this setScoreNum scoreNum this.scoreNum + amount

Part C)

this addMouseClickOnObjectListener setOfVisuals new Visual[] this.bunny,
this.penguin, this.poodle

declare procedure mouseClicked

do in order

   if event getModelAtMouseLocation == this.bunny
       this.score UpdateScore amount: 2
   else
       if event getModelAtMouseLocation == this.penguin
           this.score UpdateScore amount: 5
       else
           this.score UpdateScore amount: 6


Part D)

You would need some kind of gamestate that would have multiple strings

gamestate = "bunny"

When you click  on the bunny you would change the game state to
"penguin"

When you click on the penguin you would change the game state to
"poodle"

When you click on the penguin you would change the game state to
"gameover"


In the event for clicking on objects you would modify it to:

If the thing you clicked on is bunny and gameState is "bunny"
then you would update the score and change the gamestate to "penguin" so
you could only get points for penguin next.

If the thing you clicked on is penguin and gameState is "penguin"
then you would update the score and change the gamestate to "poodle" so
you could only get points for poodle next.

If the thing you clicked on is poodle and gameState is "poodle"
then you would update the score and change the gamestate to "gameover".

This gamestate forces the user to click on the bunny once, then penguin
once and then poodle once. 

OR

Another way is to check if score is 0 and opacity of bunny > 0.95
  then update score by 2 and change the opacity of the bunny to 0.9
if score is 2 and opacity of penguin > 0.95
  then update score by 5 and change the opacity of the penguin to 0.9
if score is 7 and opacity of poodle > 0.95
  then update score by 6 and change the opacity of the poodle to 0.9

Problem 9

Part A)
Paint function newPaintColor
do in order
    WholeNumber randomNumber <- nextRandomIntegerFrom AUpToAndIncludingB 1, 4
    if randomNumber == 1 is true then
        return RED
    else
        if randomNumber == 2 is true then
	    return BLUE
	else
	    if randomNumber == 3 is true then
	        return YELLOW
	    else
	        return GREEN

Part B)

declare WholeNumber function countPaintColors with parameters Paint paint1, Paint paint2
do in order
    WholeNumber count <- 0
    for each Penguin onePenguin in this.penguins
        if either onePenguin getPaint == paint1 OR onePenguin getPaint == paint2
	    count <- count + 1
	else

     loop
     return count


Part C)

for each Penguin somePenguin in this.penguins
    somePenguin setPaint somePenguin newPaintColor
loop
this.penguin say "Number of penguins red or green is " + this
    countPaintColors paint1 RED, paint2 GREEN