Object-Oriented Programming Languages
Question 1 (30 points). Polymorphism is one cornerstone of Object-Oriented Programming. This question has the following setting of a polymorphism problem:
Class Animal:
Attributes:
Leg, an integer, private à The number of legs
Behaviors:
Animal(), public à default constructor sets Leg=4
talk(), public à Takes no input parameter, prints out a string
“Animal can’t talk !”
End Class Animal
Class Cow:
Attributes:
An object of type Cow has all the attributes of an
object of type Animal
Behaviors:
An object of type Cow has all the behaviors of an object of
type Animal
Additionally, Cow overrides the talk( ) method:
talk(), public à Takes no input parameter, prints out a string
“Moo !”
End Class Cow
Class Pig:
Attributes:
An object of type Pig has all the attributes of an
object of type Animal
Behaviors:
An object of type Pig has all the behaviors of an object of
type Animal
Additionally, Pig overrides the talk( ) method:
talk(), public à Takes no input parameter, prints out a string
“Grunt !”
End Class Pig
Class Snake:
Attributes:
An object of type Snake has all the attributes of an
object of type Animal
Behaviors:
An object of type Snake has all the behaviors of an object of
type Animal
End Class Snake
In a main( ) routine, do the following things:
· Create a one-dimension array of type Animal with four elements
· Create an instance of each class type, i.e., Animal, Cow, Pig and Snake
· Assign each instance to an element of the array we just created
· Do a loop over each array element, and call the talk( ) method of that array element to demonstrate how the polymorphism works.
This question consists of four following sub-questions:
(a) Implement the above polymorphism problem in C++, and test the results in you main( ) routine;
(b) Implement the above polymorphism problem in Java, and test the results in you main( ) routine;
(c) Implement the above polymorphism problem in C#, and test the results in you Main( ) routine;
(d) Summarize what are your findings about the polymorphism of C++, Java, and C#. What are the differences between them ?
Question 2 (30 points)
Inheritance is another corner stone of Object-Oriented Programming. Multiple inheritance or its equivalent counterpart frequently appears in commercial codes. This question has the following setting of a multiple inheritance problem:
Class Pianist:
Attributes:
name, a string, private à The name of pianist
Behaviors:
Pianist(string x), public à default constructor sets name=x
pianoPlay(), public à Takes no input parameter, prints out a string “Play a piano !”
End Class Pianist
Class Violinist:
Attributes:
Not available
Behaviors:
violinPlay(), public à Takes no input parameter, prints out a string “Play a violin !”
End Class Violinist
Class Musician:
Attributes:
An object of type Musician has all the attributes of an
object of type Pianist
Behaviors:
An object of type Musician has all the behaviors of an object of
type Pianist and type Violinist
Additionally, Musician overrides the talk( ) method:
sing(), public à Takes no input parameter, prints out a string
“Sing a song !”
End Class Musician
In a main( ) routine, do the following things:
· Create an instance of type Musician
· Perform the sing( ) action of this instance
· Perform pianoPlay( ) action of this instance
· Perform violinPlay( ) action of this instance.
This question consists of four following sub-questions:
(a) Implement the above inheritance problem in C++, and test the results in you main( ) routine;
(b) Implement the above inheritance problem in Java, and test the results in you main( ) routine;
(c) Implement the above inheritance problem in C#, and test the results in you Main( ) routine;
(d) Summarize what are your findings about the multiple inheritance of C++, Java, and C#. What are the similarity and difference between them ?
Hint: for sub-questions (b) and (c), you may consider using interface.
Question 3 (30 points)
Information hiding is a unique feature of Object-Oriented Programming. Sometimes, we may want to break the regular access rule via friend, package, internal, or inner class. This question has the following setting of an information hiding problem:
Class Bank:
Attributes:
name, a string, private à The name of bank
securityInfo, a string, protected à The security information
of bank
Behaviors:
display(), public à Takes no input parameter, prints out a string “This is a bank !”
End Class Bank
Class Manager:
Attributes:
id, an integer, private à The id number of manager
Behaviors:
display(), public à Takes no input parameter, prints out a string “I am a manager !”
securityAccess(Bank x), public à Takes an input parameter of type Bank, prints out a string: “Security Information is : ” + x.securityInfo
End Class Manager
In a main( ) routine, do the following things:
· Create an instance of type Bank
· Create an instance of type Manager
· Call securityAccess via the instance of Manager and Bank
This question consists of four following sub-questions:
(a) Implement the above problem in C++ via friend class, and test the results in you main( ) routine;
(b) Implement the above problem in Java via the same package, and test the results in you main( ) routine;
(c) Implement the above problem in C# via internal, and test the results in you Main( ) routine;
(d) Summarize what are your findings about breaking the conventional access rule. What are the similarity and difference between friend, package, and internal ?
Submission of Your Work:
(1) The Word document should contain the following information
