Week 11 Part 2

Question 1

o T/F – each element in an Array is the same data type.

Answer 1

True

Question 2

o T/F – Each element in an array is differentiated by a subscript

Answer 2

True

Question 3

o T/F – Each array element can be used in the same way as a single item of the same data type

Answer 3

True

Question 4

o Arrays can be used to replace __ structures with several different user inputs

Answer 4

if

Question 5

o It’s good practice to use _________ for array sizes

Answer 5

constants

Question 6

o Why are constants good for array sizes?

Answer 6

Easier to change the array size later, removes magic numbers

Question 7

o The most basic method of searching an array is

Answer 7

A linear search in a loop where the loop control variable also acts as the arrays index

Question 8

• What is a Parallel Array?

Answer 8

An array that runs concurrent to another. One array for different pieces of data.

Question 9

• Why should we not use Parallel Array in Java?

Answer 9

High maintenance, you need to keep the array indexes synchronized

Question 10

o Solution to Parallel Array problem

Answer 10

Create a record object that an array can reference instead

customer Cust = new Customer(id, name, house);
Index[index] = customerId(index+1, name, house)
index [2] = customerId(index+1, name, house)

Question 11

o A ___ loop is a natural way to sequentially access each element in an array. What is this process known as?

Answer 11

For, iterating over the array

Question 12

What is an array in Java?

Answer 12

An object or reference type. It’s of reference regardless of whether the stored values are primitive.

Question 13

Java can have elements of __________ type or _________

Answer 13

primitive, reference

Question 14

o In java indexes are ____ or anything that can be promoted to an ___

Answer 14

Ints, int

Question 15

o The lowest index value for an array is _

Answer 15

0

Question 16

o T/F – In java, an array can be resized after it is instantiated

Answer 16

False

Question 17

T/F - every array has a final instance field “length”

Answer 17

True

Question 18

o What is the command for the size of the array? Will this let you change the array size?

Answer 18

arrayName.length. No

Question 19

o Once instantiated, are arrays aware of their size in Java?

Answer 19

Yes

Question 20

o A: DataType arrayName[]; B: DataType[] arrayName; Which syntax is preferred?

Answer 20

B

Question 21

o Array reference variables are automatically set to ____ after they are declared

Answer 21

Null (might be better to set this explicitly to help other programmers)

Question 22

o If we declare an array - num int[] numbers; - Does this place an array object in memory?

Answer 22

 No, this is only a declaration

Question 23

o Are either of these local scope array reference variables initialized? Is this behaviour consistent with other local scope reference variables?

Public void doStuff(){
String[] someNumbers;
String[] otherNumbers = null; }

Answer 23

String[] someNumbers is not initialized, String[] otherNumbers = null is initialized.

This is the same as other local scope reference variables. NOTE – they are still just declarations, not array objects

Question 24

o T/F – You are permitted to specify the size of the array in the same box when declaring it in Java

Answer 24

False

Question 25

o T/F – You are permitted declare and initialize an Array on the same line

Answer 25

True