Deck 10: Introduction to Inheritance

Question 1

When you declare a property defined in a base class as override in a derived class, this new declaration overrides and ____ its counterpart in the parent class.

A) eliminates
B) removes
C) uses
D) hides

Answer 1

D

Question 2

The Equals() method compares two objects and returns true if they have the same value.

Answer 2

False

Question 3

A class that inherits from a base class is a ____.

A) base class
B) derived class
C) superclass
D) parent class

Answer 3

B

Question 4

A class that is used as a basis for inheritance is called a(n) ____.

A) child class
B) extended class
C) base class
D) subclass

Question 5

When presented with two classes that have a parent-child relationship, you can tell which class is the base class and which is the derived class by using the two classes in a sentence with the phrase ____.

A) "is a"
B) "in a"
C) "of a"
D) "uses a"

Question 6

A ____ is a synonym for a derived class.

A) parent class
B) superclass
C) base class
D) subclass

Question 7

When a derived class contains a method that overrides a parent class method, you can use the keyword ____ to access the parent class method from within the derived class.

A) base
B) super
C) upper
D) parent

Question 8

A(n) ____ data field or method can be used within its own class or in any classes extended from that class, but it cannot be used by "outside" classes.

A) protected
B) public
C) private
D) internal

Question 9

A ____ is a synonym for a derived class.

A) parent class
B) second class
C) base class
D) child class

Question 10

A base class member that is not hidden by the derived class is ____ in the derived class.

A) overridden
B) removed
C) visible
D) eliminated

Question 11

In C#, you can use either new or ____ when defining a derived class member that has the same name as a base class member.

A) cast
B) hide
C) override
D) overload

Question 12

If a base class and a derived class have methods with the same names but different parameter lists, the derived class method overrides the base class method.

Question 13

A superclass contains all the fields and methods of its subclasses as well as its own more specific fields and methods.

Question 14

You can assign a derived class object to an object of any of its superclass types. When you do, C# makes a(n) ____ conversion from derived class to base class.

A) explicit
B) implicit
C) real
D) strong

Question 15

Every class you create in C# derives from a single class named ____.

A) System.Console
B) System.Object
C) System.Class
D) Object.System

Question 16

The keyword ____ is an alias for the System.Object class.

A) object
B) base
C) super
D) parent

Question 17

When you use information hiding by selecting which properties and methods of a class to make public, you are assured that your data will be altered only by the properties and methods you choose and only in ways that you can control.

Question 18

A class's ToString() method is often a useful debugging aid.

Question 19

A(n) ____ is a synonym for a base class.

A) derived class
B) parent class
C) extended class
D) child class

Question 20

Classes that depend on field names from parent classes are said to be ____ because they are prone to errors.

A) solid
B) fixed
C) fragile
D) sound

Question 21

What are the requirements for overloading the Object class's Equals() method?

Question 22

____________________ are methods that you can write to add to any type, even if you did not create the original class.

Question 23

Explain the sequence of constructors that will be called when you create an object that is an instance of a derived class.

Question 24

Briefly describe the four public instance methods of the Object class.

Question 25

Inheritance is ____________________, which means a child inherits all the members of all its ancestors.

Question 26

The keyword ____ always refers to the superclass of the class in which you use it.

A) super
B) parent
C) upper
D) base

Question 27

The ability to inherit from more than one class is called ____.

A) polymorphism
B) interfacing
C) collaboration
D) multiple inheritance

Question 28

The ____ Object class method returns a string that holds the name of the class, just as GetType() does.

A) GetHashCode()
B) Equals()
C) GetName()
D) ToString()

Question 29

A(n) ____ method has no method statements; any class derived from a class that contains one must override it by providing a body.

A) concrete
B) overloaded
C) abstract
D) overridden

Question 30

A ____ is sometimes called a "fingerprint" for an object because it uniquely identifies the object.

A) property
B) hash code
C) derived code
D) new property

Question 31

A(n) ____________________ method is one that can be overridden by a method with the same signature in a child class.

Question 32

When a derived class contains a method or property that overrides a parent class method or property, how can you use the parent class version from within the subclass? Show an example of a derived class that overrides a parent class method, but then uses the parent class method.

Question 33

On some occasions, you might want to access parent class data from a child class. Declaring the parent class field as public would violate the principle of information hiding, but declaring it private would make it inaccessible. How can the proper level of security be achieved?

Question 34

A(n) ____ class is one from which you cannot create concrete objects, but from which you can inherit.

A) abstract
B) concrete
C) base
D) derived

Question 35

The entire list of parent classes from which a child class is derived constitutes the ____________________ of the subclass.

Question 36

Show an example of a class definition that creates a subclass of an existing Employee class, and adds a private double field called commissionRate . What is the total set of fields that an instance of the new class contains?

Question 37

The ability to inherit from more than one class is called multiple inheritance. C# prohibits multiple inheritance, but it does provide an alternative mechanism. Why is multiple inheritance prohibited, and what is the alternative that is provided?

Question 38

C# makes implicit conversions when casting one data type to another. When a derived class object is assigned to its ancestor's data type, the conversion can more specifically be called a(n) ___________________________________.

Question 39

Briefly describe the similarities and differences between abstract classes and interfaces.

Question 40

When all base class constructors require arguments, you must include a constructor for each derived class you create. Why?

Question 42

Reusing existing classes and interfaces makes the job of programming easier. What are some of the future advantages that come from writing extendable base classes?