Finals Notes V

Question 1

How do you declare a NoNullArrayList?

Answer 1

public class NoNullArrayList < T > extends ArrayList < T > {}

Question 2

How do you declare an OrderedArrayList?

Answer 2

public class OrderedArrayList< T extends Comparable< T» extends NoNullArrayList< T>

Question 3

What is bubble sort? What is its worst case?

Answer 3

• Goes through index x and x + 1 until end is reached
• Worst case is n – 1 passes

Question 4

What is Optimized Bubble Sort?

Answer 4

Uses swappedFlag to see if any swaps occur

Question 5

What is selection sort? What is its worst case?

Answer 5

• Selects first element as minimum
• Changes what “minimum” is as comparisons continue
• Worst case is n – 1 passes

Question 6

What is insertion sort?

Answer 6

• Assumes that element at index 0 is sorted
• Uses the second index as a key, then the third index, etc.

Question 7

What does Math.random() do?

Answer 7

Returns a number from 0.0 to 1.0 (exclusively).

Question 8

What are the formulas for printing a number between a (inclusive) and b (inclusive)?

Answer 8

(int) ((Math.random() * range) + min)
(rand.nextInt(range) + min)
Where range = max - min + 1

Question 9

What are the formulas for printing a number between a (inclusive) and b (exclusive)?

Answer 9

(int) (Math.random() * range) + min)
(rand.nextInt(range) + min)
Where range = max - min

Question 10

How do you declare a Random class?

Answer 10

Random rand = new Random();

Question 11

What does String[] args do?

Answer 11

Allows a program to receive input from the command line

Question 12

What is args used for?

Answer 12

A String array

Question 13

What is abstraction?

Answer 13

Abstraction hides certain details and shows only the essential information to the user.

Question 14

What are some characteristics of abstract classes?

Answer 14

• Cannot create objects.
• Must be inherited from another class.

Question 15

What are abstract methods?

Answer 15

• Can only be used in abstract classes
• Does not have a body.
• Subclasses will inherit and define the bodies.

Question 16

When using interfaces, what replaces the word extends?

Answer 16

implements

Question 17

What does an interface do?

Answer 17

States the necessary methods with no bodies.