CompSci 94 Exam 3 Fall 2024 Solutions

Problem 1: 

1.A. 
10 times

1.B.1 
amount <- amount - 5

OR:

amount <- amount - 6

OR: 

amount <- amount - 7

The number to subtract could also be any number from 5 to 7. 

1.B.2

If you use amount <- amount - 5, 
   then panda says: amount is 0

If you use amount <- amount - 6, 
   then panda says: amount is -3

If you use amount <- amount - 7, 
   then panda says: amount is -6

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Problem 2:

2 A) First, each animal in the array says rain, one at a time in this order: 
pig, panda, tortoise, yetiBaby, bunny. 

Next, all the objects in the array animals (pig, panda, tortoise, yetiBaby and bunny)
say Duke at the same time

Last, the panda is painted yellow. 

2 B) The pig turns green. 
Then the panda turns red.
Then the tortoise turns blue.
Then the yetiBaby turns yellow. 
Then the bunny turns black.

2 C) There are five animals in the array at index positions 0 to 4. The
while loop condition:

   while indexTwo < 6

means that when indexTwo is 5, the next line 

  if this.animals[indextwo] not equal to this.pig

will freeze because this.animals does not have a position 5. 

To fix the error, change the while condition to:

   while indexTwo < 5

OR change the while condition to:

   while indexTwo < animals.length 

since animals.length would be 5 in this case. 



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Problem 3:

A) Biped

B) someAnimal

C) SJointedModel

D) the pig says hello

E) The bunny says The End

F) The mystery function returns the animal in the array animals that is
furthest from the parameter someAnimal


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Problem 4:

4.A) The pig says "Donuts are yummy"

4.B) The bunny moves up 0.25

4.C) Hare turns right 0.5 (halfway around)

4.D) nothing happens. Hare is not in the set of visuals array. 

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Problem 5:

A) bunny says one, hare says four, and pig says six

B) hare says two, hare says four, panda says five 

C) nothing happens. They are in the same set. 

D) bunny says one, hare says four, panda says five


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Problem 6:

The bunny moves right 1.0 and collides with yetiBaby,  and at the same time the hare move left 1.0 and collides with the pig

Next, the yetiBaby moves backwards 1.0 and at the same time the hare turns all 
the way around and also at the same time the pig moves forward 1.0

Next, the hare moves right 1.0 and collides with yetiBaby

Next, the yetiBaby moves backwards 1.0

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Problem 7:

A) The pig moves right 1
Then the hare moves left 1
Then the pig moves backward 1

B) 
If the user pressed the R key, the bunny turns all the way around once. 

 If the user presses any other key than R, the yetiBaby moves backward once. 
*) If the user presses any other key then R again, the yetiBaby moves backward once again,
and this time collides with the pig. That results in the hare moving left once and the 
pig moving backward once. 
The star move can happen over and over again if the user keeps pressing any key other 
than the R key. 
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Problem 8:

A) The poodle says: Click on me to start
When you click on the poodle, the timer appears with value 20 and starts counting down,
subtracting 1 every second.

B) declare procedure updateTimer with parameter: WholeNumber amount

this setTimerNumber this.timerNumber - amount
this setValue "" + this.timerNumber

C) 
if this.poodle getOpacity > 0.95
    this.Timer initializezTimer startValue 20
    this.poodle setOpacity 0.9

D) 
if getModelAtMouseLocation == bunny
    this.Timer updateTimer amount: -5
if getModelAtMouseLocation == yetiBaby
    this.Timer updateTimer amount: 3

E) while this.timerNumber > 0 and this.scoreNumber < 10


F) not graded


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Problem 9:

A) declare DecimalNumber function randomOpacity

WholeNumber randominteger <- nextRandomWholeNumberFromAUpToAndIncludingB 1, 4
if randomInteger == 1 is true then
    return 0.0
else
    if randomInteger == 2 is true then
        return 0.25
    else
        if randomInteger == 3 is true then 
            return 0.5
        else
            return 0.75


B) declare WholeNumber function howManyInRange with parameters: DecimalNumber minRange, 
      DecimalNumber maxRange

WholeNumber count <-- 0
for each Penguin onePenguin in this.penguins
    if BOTH onePenguin getOpacity >= minRange AND onePenguin getOpacity <= maxRange
        count <= count + 1
    else
    
loop
return count



C) declare procedure myFirstMethod


for each Penguin somePenguin in this.penguins
    somePenguin setOpacity this randomOpacity 
this.penguin say "Number of penguins with opacity from 0.25 to 0.75 is " + this howManyInRange 
      minRange 0.25, maxRange 0.75
this.penguin2 say "Number of penguins with opacity from 0.25 to 0.5 is " + this howManyInRange 
      minRange 0.25, maxRange 0.5