Question 1

When a programmer calls the next function on an iterator object, what happens if there is no current item in the sequence?

Accepted Answer

A)   the previous item is returned
B)   the compiler generates an error
C)   a StopIteration exception is raised
D)   the None item is returnedE) A) and B)
F) B) and C)

Question 2

When creating the AbstractCollection class, which methods must you modify to provide default behavior?

Accepted Answer

A)   __len__ and count
B)   __str__ and __eq__
C)   isEmpty and add
D)   __init__ and __len__E) All of the above
F) A) and C)

Question 3

How is creating a subclass of an existing class different from copying the code from the existing class to a new file?

Accepted Answer

A)   delete all the methods that don't have to change
B)   you don't need an __init__ method
C)   the name of the subclass is in parentheses of the class header
D)   no methods need be created or modifiedE) A) and B)
F) B) and D)

Question 4

In which situation is a search unnecessary when performing the add method on a sorted bag?

Accepted Answer

A)   when the bag is full
B)   when the new item is less than the last item
C)   when the new item is greater than the first item
D)   when the bag is emptyE) B) and D)
F) A) and B)

Question 5

A class that uses lists can use the methods defined in the AbstractCollection class.

Accepted Answer

A) True 
 B)False

Question 6

An instance variable that refers to an integer in two different related classes is a likely candidate to be moved to an abstract class.

Accepted Answer

A) True 
 B)False

Question 7

A class that inherits properties from another class is called a superclass.

Accepted Answer

A) True 
 B)False

Question 8

When implementing the __init__ method in the AbstractBag class, what task should you leave out because it is the responsibility of the subclasses?

Accepted Answer

A)   setting the self.size variable to 0
B)   adding items from the source collection
C)   initializing the self.items variable
D)   checking if a source collection existsE) B) and C)
F) C) and D)

Question 9

What is one of the primary purposes of using inheritance?

Accepted Answer

A)   to customize an existing class
B)   to create code redundancy
C)   to avoid creating an __init__ method
D)   to duplicate methods in an interfaceE) None of the above
F) A) and B)

Question 10

Which of the following is true about abstract classes?

Accepted Answer

A)   they are the same as a class interface
B)   the are always a subclass of a superclass
C)   they are not normally instantiated in client applications
D)   they are used as concrete classes by client applicationsE) A) and B)
F) A) and C)

Exam 6: Inheritance and Abstract Classes

When a programmer calls the next function on an iterator object, what happens if there is no current item in the sequence?

Correct Answer
verified

What is one of the primary purposes of using inheritance?

Correct Answer
verified

When implementing the init method in the AbstractBag class, what task should you leave out because it is the responsibility of the subclasses?

Correct Answer
verified

An instance variable that refers to an integer in two different related classes is a likely candidate to be moved to an abstract class.

Correct Answer
verified

When creating the AbstractCollection class, which methods must you modify to provide default behavior?

Correct Answer
verified

A class that uses lists can use the methods defined in the AbstractCollection class.

Correct Answer
verified

A class that inherits properties from another class is called a superclass.

Correct Answer
verified

Which of the following is true about abstract classes?

Correct Answer
verified

How is creating a subclass of an existing class different from copying the code from the existing class to a new file?

Correct Answer
verified

In which situation is a search unnecessary when performing the add method on a sorted bag?

Correct Answer
verified

Exam 6: Inheritance and Abstract Classes

When a programmer calls the next function on an iterator object, what happens if there is no current item in the sequence?

Correct AnswerverifiedShow Answer

What is one of the primary purposes of using inheritance?

Correct AnswerverifiedShow Answer

When implementing the __init__ method in the AbstractBag class, what task should you leave out because it is the responsibility of the subclasses?

Correct AnswerverifiedShow Answer

An instance variable that refers to an integer in two different related classes is a likely candidate to be moved to an abstract class.

Correct AnswerverifiedShow Answer

When creating the AbstractCollection class, which methods must you modify to provide default behavior?

Correct AnswerverifiedShow Answer

A class that uses lists can use the methods defined in the AbstractCollection class.

Correct AnswerverifiedShow Answer

A class that inherits properties from another class is called a superclass.

Correct AnswerverifiedShow Answer

Which of the following is true about abstract classes?

Correct AnswerverifiedShow Answer

How is creating a subclass of an existing class different from copying the code from the existing class to a new file?

Correct AnswerverifiedShow Answer

In which situation is a search unnecessary when performing the add method on a sorted bag?

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

When implementing the init method in the AbstractBag class, what task should you leave out because it is the responsibility of the subclasses?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified