Deck 12: Father Was a Rectangle: Inheritance and Object-Oriented Design

Question 1

The ____ relationship describes two objects where one object is a more specific instance of the other.

A) OF-A
B) HAS-A
C) IS-A
D) BELONGS-TO

Answer 1

C

Question 2

The ______ relationship describes two objects where one object uses another object.

A) OF-A
B) HAS-A
C) IS-A
D) BELONGS-TO

Answer 2

B

Question 3

In a hierarchy diagram, the most ____ object is at the top.

A) general
B) specific
C) complicated
D) simple

Answer 3

A

Question 4

In inheritance, the more general class is called the ____ class.

A) child
B) superclass
C) model
D) subclass

Question 5

When two classes are connected by an IS-A link, what do we call a class that inherits from a higher class in the inheritance hierarchy?

A) Subclass
B) Method
C) Instance variable
D) Superclass

Question 6

In an expanded object hierarchy for shapes, which of the following would be the most specific (or least general) class?

A) GeometricObject
B) Shape
C) Ellipse
D) Square

Question 7

Case Study 1:
1. myCanvas = Canvas (800, 600)
2. myLine = Line(Point (-100, -100), Point (100, 100))
3. myCanvas.draw(myLine)
-Refer to the session in the accompanying Case Study 1. What can be inferred about the Canvas class?

A) It will have a draw method.
B) It will be constructed with two Points.
C) It does not have a constructor.
D) It will have three instance variables.

Question 8

Case Study 1:
1. myCanvas = Canvas (800, 600)
2. myLine = Line(Point (-100, -100), Point (100, 100))
3. myCanvas.draw(myLine)
-Refer to the session in the accompanying Case Study 1. What can be inferred about the Point class?

A) It has a method draw.
B) It is required to create a Canvas.
C) It has at least two instance variables.
D) It is a subclass.

Question 9

The ____ method of the screen is used to define the width and height.

A) __init__
B) setup
C) move
D) setWidth

Question 10

What is the name of the property that allows Python to call the right method of an object depending on the type of object referenced by a superclass?

A) Polymorphism
B) Inheritance
C) Abstraction
D) Mutation

Question 11

In the object hierarchy presented in the text, GeometricObject is a(n) ____ class.

A) sub
B) specific
C) abstract
D) parameter

Question 12

How do you call the constructor of a superclass within a subclass?

A) __init()__
B) super().__init__()
C) super()
D) parent().init()

Question 13

How do you designate that B is a parent class of A?

A) class A extends B
B) class A[B]
C) class A(B)
D) class A of B:

Question 14

Case Study 2:
1. >>> myLine
2. &It;draw.Line object at 0x106f6b0>
3. >>> myCanvas
4. &It;draw.Canvas instance at 0x1070328>
5. >>> isinstance(myLine, Line)
6. ??????
-Refer to the session in the accompanying Case Study 2. What is output on line 6?

A) True
B) False
C) Line
D) myLine

Question 15

What variable holds the name of the parent of a class?

A) __parent__
B) __self___
C) __super__
D) __bases__

Question 16

When designing a project, it is a good idea to begin by making a list of the different kinds of objects involved and the relationships between those objects.

Question 17

The class where the IS-A link originates is called the superclass.

Question 18

It is good programming practice to write all the code for a large program at once and then to test it.

Question 19

The constructor method is always named __init__.

Question 20

The __dict__ variable is a dictionary that keeps track of the methods defined for the class.

Question 21

Match each definition with its term.
-A more general class.

A) Superclass
B) Abstract class
C) Subclass
D) The object class

Question 22

Match each definition with its term.
-Provides us with one place to define instance variables and methods used by subclasses.

A) Superclass
B) Abstract class
C) Subclass
D) The object class

Question 23

Match each definition with its term.
-A more specific class.

A) Superclass
B) Abstract class
C) Subclass
D) The object class

Question 24

Match each definition with its term.
-The class from which all classes inherit.

A) Superclass
B) Abstract class
C) Subclass
D) The object class

Question 25

What is the difference between an IS-A relationship and a HAS-A relationship?

Question 26

What is inheritance? As an example, explain how Shape and a Rectangle are related.

Question 27

Explain the benefits of using inheritance when creating a program that uses a variety of shapes with common characteristics.

Question 28

Explain how the Canvas draw method presented in your text makes use of the _draw method in GeometricObject.

Question 29

How does a Python object reference the class of which it is an instance?

Question 30

Explain how Python evaluates the expression myLine.getWidth().

Question 31

Describe the visibleObject instance variable that was added to the Canvas class presented in your text. How does this variable help improve drawing?

Question 32

Describe the drawAll method of the Canvas class presented in your text.