1. An abstract data type is not necessarily a collection.

True/False (10)

• An abstract data type is not necessarily a collection.

Answer: true

• A collection is not necessarily an abstract data type.

Answer: false

• Entries of a bag can belong to classes related by inheritance.

Answer: true

• Entries of a bag may belong to different classes because items are unordered.

Answer: false

• All entries of a bag must have the same data type or a subtype of that data type.

Answer: true

• By declaring a data type to be a BagInterface, we can replace the bag class with another class

that implements the BagInterface.

Answer: true

• A method can change the state of an object passed to it as an argument.

Answer: true

• A set is a special kind of bag.

Answer: true

• You cannot determine the exact number of times a particular item appears in a bag because it is

unordered.

Answer: false

• Code written with respect to an interface makes it difficult to replace one implementation of a

bag with another.

Answer: false

(Data Structures and Abstractions with Java, 5e Frank Carrano, Timothy Henry) (Test Bank all Chapters) 1 / 4

Short Answer (5)

• Explain the rationale for returning a Boolean value from the add bag operation.

Answer: A client should know what happened. A Boolean value indicates true for success or false for a failed operation.

• Explain why writing a test program before implementing a class is a good idea.

Answer: It helps you understand the specifications before committing to your design and implementation.

• Explain why the set ADT does not need a getFrequencyOf operation.

Answer: Because sets do not contain duplicate items, only a 0 for absence or 1 for presence of an item would be returned. Using a contains method is a better design.

• What is the design rationale for providing a toArray method instead of a displayBag method?

Answer: The user/client is free to display any or all of the items in any way desired.

• Explain why null is a potential return value for the remove operation.

Answer: It is a value that cannot be in the bag and therefore signals a problem if, for example, a client tries to remove an entry from an empty bag.

Multiple Choice (30) WARNING: CORRECT ANSWERS ARE IN THE SAME POSITION AND TAGGED

WITH **. YOU SHOULD RANDOMIZE THE LOCATION OF THE CORRECT ANSWERS IN YOUR EXAM.

• A language-independent specification for a group of values and operations on those values is

called a/an:

• abstract data type **
• data structure
• collection
• primitive

2. An implementation of an ADT with a programming language is called a/an:

• data structure **
• abstract data type
• collection
• primitive

• An object that groups other objects and provides services to its clients is called a/an:
• collection ** 2 / 4

• abstract data type
• data structure
• primitive

• Which of the following is not true with regard to bags?
• objects are in a specific order **
• can contain duplicate items
• is an abstract data type
• is a kind of collection in Java

• Which behavior is not represented in a bag?
• reorder the bag **
• report the number of items in the bag
• report if the bag is empty
• add an item to the bag

• Which method returns a count of the current number of items in a bag?
• getCurrentSize() **
• getSize()
• size()
• currentSize()

• Why would the add method return false?
• when the addition of a new item was not successful **
• when there was a duplicate of the entry already in the bag
• when there was not a duplicate of the entry already in the bag
• when addition of a new item was successful

• Which method removes all entries of a bag?
• clear() **
• remove()
• delete()
• empty()

• Which method removes one unspecified entry from a bag if possible?
• remove() **
• clear ()
• delete()
• empty()

• Which method removes one occurrence of a particular entry from a bag if possible?
• remove(anItem) ** 3 / 4

• clear (anItem)
• delete(anItem)
• empty(anItem)

• Which behaviors do not change the contents of a bag?
• add()
• clear()
• remove()
• none of the above **

• Which behaviors change the contents of a bag?
• clear()
• remove()
• add()
• all of the above **

• Which method can be used to retrieve all of the elements of a bag?
• toArray() **
• printBag()
• displayBag()
• getAllItems()

14. When using abstraction as a design principle you should focus on:

• what you want to do with the data **
• how the data is stored
• how the data is manipulated
• all of the above

• Which of the following is a special kind of bag that does not allow duplicate entries?
• set **
• collection
• extended bag
• super bag

• Which of the following are properties of a set?
• duplicates are permitted **
• elements are stored in order
• elements may not be removed
• none of the above

• When adding an item to a bag, which of the following statements are true?
• You cannot specify the position of the item in the bag. **
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