Exam 2

Question 1

An array is an indexed structure:

Answer 1

elements may be accessed in any order using subscript

elements can be accessed in sequence using a loop that increments the subscript

Question 2

With Java arrays object , you cannot

Answer 2

increase or decrease its length (length is fixed )

insert an element at a specified position

remove an element at a specified position

Question 3

A _____ is a collection of elements, each with a position

Answer 3

list

Question 4

In Java, the methods to be implemented by lists are defined in the ____ interface

Answer 4

List

Question 5

Classes that implement the List interface provide the functionality of an array and offer several operations :

Answer 5

Obtain an element at a specified position

Replace an element at a specified position

Find a specified target value

Add an element at either end a

Remove an element from either end

Insert or remove an element at any position

Traverse the list

Question 6

The simplest class that implements the List interface

Answer 6

ArrayList class

Question 7

Use an ArrayList class when:

Answer 7

you will be adding new elements to the end of a list

you need to access elements quickly in arbitrary order

Question 8

How do you declare a List “object” whose elements will reference String objects :

Answer 8

List myList = new ArrayList();

Question 9

ArrayList is empty and has a default capacity of:

Answer 9

10 elements

Question 10

In an ArrayList, you cannot access an element using a bracket index as you can with arrays (array[1]).

Instead use _____ method.

Answer 10

get()

Question 11

How to search an ArrayList to get location

Answer 11

.indexOf()

Question 12

List myList new ArrayList <>() ; language feature called:

Answer 12

generics

Question 13

The statement creates a List of Strings; only references of type String can be stored in the list

Answer 13

Generic collections

Question 14

In generic collection, String in this statement is called a:

Answer 14

type parameter

Question 15

The _______________ sets the data type of all objects stored in a collection

Answer 15

type parameter

Question 16

The general declaration for generic collection is:

Answer 16

CollectionClass ab1e= new 1ass<>() ;

Question 17

In a generic collection The indicates a:

Answer 17

type parameter

Question 18

Adding a noncompatible type to a generic collection will generate an error during:

Answer 18

compile time

Question 19

The elements of a list can be of any type, including your own classes :

Answer 19

List inventory new ArrayList (); = new ArrayList();

Question 20

In order to use _______ with a List of user-defined objects, there must be a way to determine when two objects are equal

Answer 20

indexof

Question 21

indexOf is done by overriding the ______ method inherited from ______

Answer 21

equals

object

Question 22

The equals method has a parameter of type:

Answer 22

Object

Question 23

How to use Object.equals

Answer 23

public boolean equals (Object other)

Question 24

What does Object.equals do?

Answer 24

Compares two references to determine if they refer to the same object:

Question 25

An Object.equals method class must _____________ for the comparison to be meaningful

Answer 25

Override equals

Question 26

How do you override an equals() in computer class?

Answer 26

``` @Override public boolean equals (Object obj) { if (obj instanceof Computer) { Computer other = (Computer) obj: return computePower() == other.computePower } (); return false ; } ```

Question 27

Internally, the elements of an ArrayList are stored in an array. Three variables are needed:

Answer 27

theData : An array to hold the elements capacity : Physical size of array size : Number of data items in the list

Question 28

We have two add methods:

Answer 28

One will append at the end of the list The other will insert an item at a specified position

Question 29

Implementing add (String anEntry), If size is less than capacity, then to append a new item:

Answer 29

insert the new item at the position indicated by the value of size increment the value of size return true to indicate successful insertion

Question 30

To insert into the middle of the array, the values at the insertion point are shifted over to make room, beginning at the end of the array and proceeding in the indicated order

Answer 30

Implementing add (int index, String anEntry)

Question 31

When an item is removed , the items that follow it must be moved ________ to close the gap

Answer 31

forward

Question 32

Creates a new array that is twice the size of the current array and then copy the contents of the new array

Answer 32

reallocate Method

Question 33

Single-linked ArrayList is limited because

Answer 33

It’s add and remove method require a loop to shift elements

Question 34

_________ is useful for inserting and removing at arbitrary locations without shifting elements, regardless of the size of the list

Answer 34

linked list

Question 35

In a linked list, instead of using an array , each element is stored in a ______ and linked to the ______ element

Answer 35

node next

Question 36

A LinkedList object can be used anywhere an ArrayList is used :

Answer 36

List < String > myList = new Linkedlist<>();

Question 37

List < String > myList = new Linkedlist<>(); The initial list is empty. How do we add strings?

Answer 37

myList.add(“Tom”);

Question 38

A list node contains :

Answer 38

a data item one (or more) link(s) (references to other node(s))

Question 39

A Linkedlist object has a data field _____, which references the first list node.

Answer 39

head

Question 40

Limitations of a singly-linked list include:

Answer 40

Insertion at the front is quickinsertion at other positions may require a list traversal to find insertion place Insertion is convenient only after a referenced node Removing a node requires a reference to the previous node We can traverse the list only in the forward direction

Question 41

Limitations such as: Insertion at the front is quickinsertion at other positions may require a list traversal to find insertion place Insertion is convenient only after a referenced node Removing a node requires a reference to the previous node We can traverse the list only in the forward direction We can overcome these limitations by:

Answer 41

Adding a reference in each node to the previous node, creating a double-linked list

Question 42

can be viewed as a moving place marker that keeps track of the current position in a particular linked list

Answer 42

An iterator

Question 43

An Iterator object for a list starts at the:

Answer 43

List head

Question 44

The programmer can move the Iterator by calling its _____ method.

Answer 44

next

Question 45

The ________ stays on its current list item until it is needed

Answer 45

Iterator

Question 46

By using an Iterator to traverse a linked list, the code segment can be:

Answer 46

rewritten so as to require n operations

Question 47

Where is the iterative interface defined?

Answer 47

In java.util

Question 48

The _____ interface declares the method ________ which returns an ________ object that iterates over the elements of that list

Answer 48

List iterator Iterator

Question 49

An Iterator is: it does not refer to a particular object at any given time

Answer 49

conceptually between elements

Question 50

How do we process all List through Iterator?

Answer 50

Iterator iter = aList.iterator(); while(iter.hasNext()) { item = iter.next(); }

Question 51

You can use the ____________ method to remove items from a list as you access them.

Answer 51

Iterator remove()

Question 52

deletes the most recent element returned in an Iterator

Answer 52

remove()

Question 53

You must call next() before each remove(); otherwise , an _________ will be thrown

Answer 53

IllegalStateException

Question 54

What’s the different LinkedList.remove(i) vs Iterator.remove

Answer 54

LinkedList.remove(i): must walk down the list each time , then remove Iterator.remove removes items without starting over at the beginning

Question 55

How do you remove all elements from a list of type Integer that are divisible by a particular value:

Answer 55

public static void remove DivisibleBy (LinkedList alist, int div) Iterator iter = aList.iterator()); while ( iter.hasNext() ) { ``` int nextInt = iter.next (); if ( nextInt % div == 0) { iter.remove(); } } } ```

Question 56

Iterator limitations: How do we overcome these limitations?

Answer 56

Traverses List only in the forward direction Provides a remove method, but no add method You must advance the Iterator using your own loop if you do not start from the beginning of the list ListIterator extends Iterator, overcoming these limitations

Question 57

ListIterator positions are assigned an index from ____ to ____

Answer 57

0 Size

Question 58

ListIterator has a method which is able to receive the proceeding and future index of items.

Answer 58

nextIndex(); | previousIndex();

Question 59

ListIterator is a subinterface of:

Answer 59

Iterator

Question 60

Classes that implement ListIterator must provide the features of:

Answer 60

Both ListIterator and Iterator

Question 61

Requires fewer methods Can iterate over more general data structures used by enhanced for loop

Answer 61

Iterator

Question 62

Iterator is required by the ________ interface

Answer 62

Collection

Question 63

ListIterator is required only by the _______ interface

Answer 63

List

Question 64

The collection interface specifically excludes: But including:

Answer 64

add (int , E) get ( int) remove ( int) set (int, E ) add (E) remove (Object) the iterator method

Question 65

In a general Collection the order of elements is:

Answer 65

not specified

Question 66

For collections implementing the List interface, the order of the elements is determined by the:

Answer 66

index

Question 67

In a general Collection, the position where an ______ is inserted is not specified

Answer 67

object

Question 68

In ArrayList and LinkedList, add (E) always inserts at the ____ and always returns:

Answer 68

end | true