Inheritance Exercises
|
gpdraw |
TwoDShape |
Exercise 3 Cylinders |
Old MacDonald |
Back to School |
Use
the base class TwoDShape (but DO USE
DEFAULT ACCESS SPECIFIER) and add a class called Rectangle that extends
TwoDShape and a class called Circle that extends TwoDShape.
Include appropriate instance
variables and methods in Rectangle and Circle that will allow setting the
instance variables and allow calculation of the area and circumference of
each and announce the results.
Always specifically state the
access specifiers.
Use the code in Example 4 and the beginnings of a driver class (CylinderTest) as listed below.
Write sufficient code to test the Cylinder class - print out the diameter, circumference, area, and volume
public class CylinderTest
{
public static void main(
String[] args )
{
//
create Cylinder object and pass parameters
// print
cylinder diameter, circumference, area, and volume
}
}
Use the code given as a starting point to develop and test the Old MacDonald Farm classes
This lab consists of the following 7 files:
1. Animal.java – interface
2 Chick.java – implementation of the Animal interface
3. Cow.java – implementation of the Animal interface
4. Pig.java – implementation of the Animal interface
5. NamedCow.java – subclass of the Cow class
6. Farm.java – collection of Animal objects
7. OldMacDonald.java – testing class
This class contains the main - and will test each of the methods for the various animals (Chick, Cow, Pig)
Back to School
Background:
A HighSchool
application has two classes: the Person
superclass and the
Student
subclass. Using inheritance, in this lab you will create two new classes,
Teacher
and
CollegeStudent.
A
Teacher
will be like Person
but will have additional properties such as salary (the amount the
teacher earns) and subject (e.g. “Computer Science”, "Chemistry",
"English", "Other”). The
CollegeStudent
class will extend the
Student
class by adding a year (current level in college) nd major
(e.g. “Electrical Engineering”, “Communications”, “Undeclared”).
The inheritance hierarchy would appear as follows:
Listed below
is the
Person
base class from the lesson to be used as a starting point for the
Teacher
class:
class
Person
{
protected
String myName ; // name
of the person
protected
int
myAge;
// person's age
protected
String myGender; // "M" for
male, "F" for female
// constructor
public
Person(String name,
int
age, String gender)
{
myName = name; myAge = age ; myGender = gender;
}
public
String toString()
{
return
myName + ", age: " + myAge +
", gender: " +myGender;
}
}
The
Student
class is derived from the
Person
class and used as a starting point for the
CollegeStudent
class:
class
Student
extends
Person
{
protected
String myIdNum; //
Student Id Number
protected
double myGPA;
// grade point average
// constructor
public
Student(String name,
int
age, String gender,
String idNum,
double
gpa)
{
// use the super class' constructor
super(name,
age, gender);
// initialize what's new to Student
myIdNum = idNum;
myGPA = gpa;
}
}
Assignment:
1. Add methods to “set” and “get” the instance variables in the Person class. These would consist of: getName, getAge, getGender, setName,
setAge,
and
setGender.
2.
Add methods to “set” and “get” the instance variables in the
Student
class. These would consist of:
getIdNum,
getGPA,
setIdNum,
and
setGPA.
3.
Write a Teacher
class that extends the parent class Person.
a. Add instance variables to the class for subject (e.g. “Computer Science”, "Chemistry",, "English", "Other”) and salary (the teachers
annual
salary). Subject should be of type
String
and salary of type
double.
Choose appropriate names for the instance variables.
b. Write a constructor for the Teacher class. The constructor will use five parameters to initialize myName, myAge, myGender, subject,
and salary.
Use the super
reference to use the constructor in the
Person
superclass to initialize the inherited values.
c. Write “setter” and “getter” methods for all of the class variables. For the Teacher class they would be: getSubject, getSalary,
setSubject,
and
setSalary.
d. Write the toString()
method for the Teacher
class. Use a super
reference to do the things already done by the superclass.
4.
Write a CollegeStudent
subclass that extends the Student
class.
a. Add instance variables to the class for major (e.g. “Electrical Engineering”, “Communications”, “Undeclared”) and year (e.g. FROSH = 1,
SOPH = 2, …).
Major should be of type
String
and year of type
int.
Choose appropriate names for the instance variables.
b. Write a constructor for the CollegeStudent class. The constructor will use seven parameters to initialize myName, myAge, myGender,
myIdNum,
myGPA,
year, and major. Use the
super
reference to use the constructor in the
Student
superclass to initialize the inherited values.
c. Write “setter” and “getter” methods for all of the class variables. For the CollegeStudent class they would be: getYear, getMajor, setYear,
and
setMajor.
d. Write the
toString()
method for the CollegeStudent
class. Use a super
reference to do the things already done by the superclass.
5. Write a testing class with a main() that constructs all of the classes (Person, Student, Teacher, and CollegeStudent) and calls their toString()
method.
Sample usage would be:
Person bob = new Person("Coach Bob", 27, "M");
System.out.println(bob);
Student lynne = new Student("Lynne Brooke", 16, "F", "HS95129", 3.5);
System.out.println(lynne);
Teacher
mrJava = new Teacher("Duke Java", 34, "M", "Computer Science",
50000);
System.out.println(mrJava);
CollegeStudent ima = new CollegeStudent("Ima Frosh", 18, "F",
"UCB123",
4.0,
1, "English");
System.out.println(ima);
A sample run of the program
would give:
Coach Bob, age: 27, gender: M
Lynne Brooke, age: 16, gender: F, student id: HS95129, gpa: 3.5
Duke Java, age: 34, gender: M, subject: Computer Science, salary: 50000.0
Ima Frosh,
age: 18, gender: F, student id: UCB123, gpa: 4.0, year: 1, major: English