Deck 10: Introduction to Inheritance

Question 1

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

Answer 1

False

Question 2

A class that is used as the basis for inheritance is known as what type of class?

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

Answer 2

C

Question 3

What kind of a class might be considered to be "fragile"?

A) A built in class that is overloaded.
B) A class that depends on being passed parameters from another method.
C) A class that depends on field names from parent classes.
D) A class that has no destructor method.

Answer 3

C

Question 4

What keyword is an alias for the System.Object class?

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

Question 5

What kind of data field or method can be used within its own class or in any classes extended from that class, but cannot be used by "outside" classes?

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

Question 6

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

Question 7

What is another name for a base class in C#?

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

Question 8

In C#, any class you create is derived from what single built-in class?

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

Question 9

When using a derived class that contains a method that overrides a parent class method, what keyword can you use to access the parent class method from within the derived class?

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

Question 10

When a class inherits from a base class, it is known as what type of class?

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

Question 11

What term is synonymous with a derived class?

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

Question 12

What happens to a base class member in a derived class that is not hidden by the derived class?

A) It is overridden by the derived class.
B) It is removed from the derived class.
C) It will be visible to the derived class.
D) It will be eliminated from the derived class.

Question 13

What happens when you declare a property defined in a base class as override in a derived class?

A) The new declaration is eliminated in favor of the old declaration.
B) The new declaration removes the old declaration at compile time.
C) The new declaration is used when the compiler deems it appropriate.
D) The new declaration overrides and hides its counterpart in the parent class.

Question 14

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 15

Besides the new keyword, what keyword can you use 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 16

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 using what phrase?

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

Question 17

You can assign a derived class object to an object of any of its superclass types.When you do, what type of conversion occurs from the derived class to base class?

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

Question 18

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

Question 19

What is another name for a derived class in the C# programming language?

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

Question 20

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 21

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

Question 22

A class that is able to inherit from more than one class utilizes what C# feature?

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

Question 23

What method can you use to return a unique hash for different objects, so long as you explicitly implement it in a derived class?

A) CalcHash()
B) GetHashGen()
C) ToHash()
D) GetHashCode()

Question 24

What 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 25

What keyword always refers to the superclass of the class in which you use it?

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

Question 26

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 27

What type of 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 28

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

Question 29

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

Question 30

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

Question 31

What statement regarding the use of the Object class and classes in general is accurate?

A) When you create any child class, no inheritance occurs automatically.
B) All classes inherit the Object class methods.
C) The object class contains a constructor, destructor, and two public instance methods.
D) Although every class descends from Object, not all objects are Objects.

Question 32

What type of method has no method statements, and requires the use of an override statement for any class derived from a class that contains it?

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

Question 33

System.Console is an example of a class that can't be extended.What is the reason for this?

A) The class has a private access modifier.
B) The class has an internal access modifier.
C) The class has a static access modifier.
D) The class has a protected access modifier.

Question 34

In the event that a method that should be overridden in a child class has its own implementation, what should you declare the base class method to be?

A) abstract
B) virtual
C) valid
D) static

Question 35

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 36

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 37

What can be used as a type of "fingerprint" for an object, due to the fact that it is unique?

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

Question 38

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

Question 39

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?

Question 40

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.