Question 1

What is the __str__ method used for?

Accepted Answer

A)   It builds and returns a string representation of an object's state.
B)   It is used to determine if a class attribute is a string.
C)   It is used to initiate string values during instantiation.
D)   It converts a string attribute within a class.E) None of the above
F) A) and B) A

Question 2

It is not usual to bother subclassing unless the two classes share a substantial amount of abstract behavior.

Accepted Answer

A) True 
 B)False

Question 3

The scope of an instance variable is the entire module.

Accepted Answer

A) True 
 B)False

Question 4

For data that are owned by individual objects, you must use class variables.

Accepted Answer

A) True 
 B)False

Question 5

The function call str(s) is equivalent to the method call s.__str__().

Accepted Answer

A) True 
 B)False

Question 6

What concept within object-oriented programming involves the restriction of the manipulation of an object's state by external users to a set of method calls?

Accepted Answer

A)   inheritance
B)   polymorphism
C)   data encapsulation
D)   data modelingE) A) and B)
F) A) and C)

Question 7

What can be used to describe and document the analysis and design of complex software systems?

Accepted Answer

A)   Class Diagraming Language
B)   Programming Structural Language
C)   Direct Modeling Language
D)   Unified Modeling LanguageE) B) and D)
F) A) and B)

Question 8

Operator overloading is an example of an abstraction mechanism.

Accepted Answer

A) True 
 B)False  True

Question 9

You are utilizing the pickle.load function to load objects into a program from a file. However, your program raises an exception as soon as the end of the file is reached. What must you do?

Accepted Answer

A)   Use an if-else statement to check if the load function is at the end of the file.
B)   Use a nested loop to run the pickle.load function line by line.
C)   Use a try-except statement to catch the exception and continue with the program.
D)   Use the pickle.len()  function to determine the size of the file, then pass the size to the pickle.load()  function using the size key.E) None of the above
F) All of the above

Question 10

What effect does using the model/view pattern of design have?

Accepted Answer

A)   It divides the roles and responsibilities of the system between data management and user interface display.
B)   It combines the roles and responsibilities of the system between data management and user interface display.
C)   It involves the user in the defining of how data will be modeled by a program.
D)   It involves the creation of a model GUI environment, and then involves the creation of views for the user to choose from.E) A) and C)
F) C) and D)

Question 11

A class variable is visible to all instances of a class and does not vary from instance to instance.

Accepted Answer

A) True 
 B)False

Question 12

What is the process in which the Python virtual machine recycles its storage known as?

Accepted Answer

A)   garbage collection
B)   trash expunging
C)   data dumping
D)   tombstoningE) None of the above
F) B) and D)

Question 13

The attributes of an object are represented as instance datum.

Accepted Answer

A) True 
 B)False

Question 14

How could you overload the addition operator in the Python language?

Accepted Answer

A)   You create a def statement with an asterisk, then specify math.__add__ as the method name.
B)   You create a new class with the same name as the arithmetic class, and define the __add__ method.
C)   You declare a new method with the same name, __add__, and define the method.
D)   You create a Python script named __add__.py, and then define the new method in that script, then import it.E) C) and D)
F) All of the above

Question 15

What statement is an accurate description of the concept of polymorphism in object-oriented programming?

Accepted Answer

A)   Polymorphism is the restricting of the manipulation of an object's state by external users to a set of method calls.
B)   Polymorphism is allowing a class to automatically reuse and extend the code of a similar but more general class.
C)   Polymorphism is the use of code that is capable of making changes to itself during the execution process.
D)   Polymorphism is allowing the several different classes to use the same general method names.E) All of the above
F) A) and D)

Question 16

At the top, or root of the class hierarchy is the most abstract class. What is the name of this class?

Accepted Answer

A)   root
B)   object
C)   parentClass
D)   MainE) B) and C)
F) None of the above

Question 17

Most object-oriented languages require the programmer to master the following techniques: data encapsulation, inheritance, and abstraction.

Accepted Answer

A) True 
 B)False  False

Question 18

Although Python is considered an object-oriented language, its syntax does not enforce data encapsulation.

Accepted Answer

A) True 
 B)False

Question 19

In general, you should use class variables only for symbolic constants or to maintain data held in common by all objects of a class.

Accepted Answer

A) True 
 B)False

Question 20

Regarding class variables, what statement is accurate?

Accepted Answer

A)   A class variable is only visible to a single instance of a class.
B)   A class variable is visible only to methods inside a class.
C)   A class variable is visible to all instances of a class, but can vary from instance to instance.
D)   A class variable is visible to all instances of a class, and does not vary from instance to instance.E) B) and C)
F) B) and D)

Exam 9: Design With Classes

What is the __str__ method used for?

Correct AnswerverifiedA

It is not usual to bother subclassing unless the two classes share a substantial amount of abstract behavior.

Correct AnswerverifiedShow Answer

The scope of an instance variable is the entire module.

Correct AnswerverifiedShow Answer

For data that are owned by individual objects, you must use class variables.

Correct AnswerverifiedShow Answer

The function call str(s) is equivalent to the method call s.__str__().

Correct AnswerverifiedShow Answer

What concept within object-oriented programming involves the restriction of the manipulation of an object's state by external users to a set of method calls?

Correct AnswerverifiedShow Answer

What can be used to describe and document the analysis and design of complex software systems?

Correct AnswerverifiedShow Answer

Operator overloading is an example of an abstraction mechanism.

Correct AnswerverifiedTrue

You are utilizing the pickle.load function to load objects into a program from a file. However, your program raises an exception as soon as the end of the file is reached. What must you do?

Correct AnswerverifiedShow Answer

What effect does using the model/view pattern of design have?

Correct AnswerverifiedShow Answer

A class variable is visible to all instances of a class and does not vary from instance to instance.

Correct AnswerverifiedShow Answer

What is the process in which the Python virtual machine recycles its storage known as?

Correct AnswerverifiedShow Answer

The attributes of an object are represented as instance datum.

Correct AnswerverifiedShow Answer

How could you overload the addition operator in the Python language?

Correct AnswerverifiedShow Answer

What statement is an accurate description of the concept of polymorphism in object-oriented programming?

Correct AnswerverifiedShow Answer

At the top, or root of the class hierarchy is the most abstract class. What is the name of this class?

Correct AnswerverifiedShow Answer

Most object-oriented languages require the programmer to master the following techniques: data encapsulation, inheritance, and abstraction.

Correct AnswerverifiedFalse

Although Python is considered an object-oriented language, its syntax does not enforce data encapsulation.

Correct AnswerverifiedShow Answer

In general, you should use class variables only for symbolic constants or to maintain data held in common by all objects of a class.

Correct AnswerverifiedShow Answer

Regarding class variables, what statement is accurate?

Correct AnswerverifiedShow Answer

What is the str method used for?

Correct Answer
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The function call str(s) is equivalent to the method call s.str().

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True

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