Unit 6 - Array

Question 1

Array

Answer 1

Data structure used to implement a collection or list of primitive or object reference data

Question 2

Element

Answer 2

single value in an array

Question 3

Index of an element

Answer 3

position of element in an array

Question 4

1st element has an index of

Answer 4

0

Question 5

Length of array

Answer 5

number of elements in an array

is a public final data member of an array

Question 6

Last element of an array is at index

Answer 6

list.length-1

Question 7

When an array of ints is created with keyword new, each element is initialized to

Answer 7

0

Question 8

Accessing an index that doesn’t exist causes an

Answer 8

ArrayIndexOutOfBoundsException

Question 9

Elements of a reference type are initialized to

Answer 9

reference value null

Objects are not automatically created

Question 10

Elements of a double type are initialized to

Answer 10

0.0

Question 11

Elements of a boolean type are initialized to

Answer 11

false

Question 12

Initializer list

Answer 12

Used to put values into an array during initialization

Question 13

Initialize an array of type boolean with 4 elements

Answer 13

boolean [ ] listOne = new boolean [4]

data type [ ] name = keyword new data type [number of elements]

Question 14

Initializer lists structure

Answer 14

data type [ ] name = { parameters separated by commas }

Example
double [ ] grades = {70.5, 88.2, 93.7, 98.7}

Question 15

Use of array objects allows multiple related items to be represented using

Answer 15

a single variable

Question 16

Square brackets are used to

Answer 16

access and modify an element in a 1D array using an index

Question 17

Valid index values

Answer 17

0 to list.length-1

Question 18

How to retrieve a value at index x from an array

Answer 18

name [index x]

Question 19

Traversing

Answer 19

Access each element of an array

Can be done by iteration statements

Question 20

A for loop can also be

Answer 20

used to access some of elements

Be sure to check LCV initialization, conditions, and increment

Question 21

When using loops to access array elements, we need to be careful to prevent an

Answer 21

ArrayIndexOutOfBoundsException

Question 22

Enhanced for loops

Answer 22

Also known as a for-each loop

Only two components separated by a colon

Question 23

What two components are in the parameter list of an enhanced for loop

Answer 23

first component -> type & name of variable that is a copy of value stored in structure

second component -> data structure being traversed with the loop

Question 24

Enhanced for loops are able to

Answer 24

access the value stored in variable

Question 25

Enhanced for loops are unable to

Answer 25

Assign into the variable defined in header

Don’t have access to indices of array or subscript notation

Question 26

Structure of enhanced for loop

Answer 26

for (type declaration : structure)
{ 
      // statement one;
      //statement two;
      // ...
}

Question 27

Algorithm to identify a max/min in an array

Answer 27

Method -> local variable needed to store current max/min values being compared to all values in array and assign value to be opposite extreme or first item
Loop -> standard or enhanced both work
-> compare current value against a local variable
currentValue is better, assign to temporary variable

Question 28

Algorithm to calculate average value from objects in an array

Answer 28

Method -> local double variable is needed to store accumulated values
for loop -> traverse the array and add current total to variable
After accumulation need to divide total by number of items stored in array

Question 29

Algorithm to shift array contents to the right

Answer 29

Make an empty array of the same size
Iterate over original array & properly copy values to adjusted index in new array
Assign new array back into original variable
Only use a standard for loop

Question 30

Algorithm to shift array contents to the left

Answer 30

Shift using same array/ go to left with use of nested for loops
Outer loop -> execute # of times we shift
Inner loop -> copy value stored in first index then move all contents one spot left
Copy temp. variable back to end of array