LAB EXERCISE

IN JAVA JGRASP

BackToSchool

Background:

The HighSchool application described in the lesson 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) and major (e.g. "Electrical Engineering", "Communications", "Undeclared").

The inheritance hierarchy would appear as follows:

Here is the Person base class from the lesson to be used as a starting point for the Teacher class:

class Person{

private String myName ; // name of the person

private int myAge; // person's age

private 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 getName() {

return myName;

}

public int getAge(){

return myAge;

}

public String getGender(){

return myGender;

}

public void setName(String name){

myName = name;

}

public void setAge(int age) {

myAge = age;

}

public void setGender(String gender){

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{

private String myIdNum; // Student Id Number

private 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;

}

public String getIdNum(){

return myIdNum;

}

public double getGPA(){

return myGPA;

}

public void setIdNum(String idNum){

myIdNum = idNum;

}

public void setGPA(double gpa){

myGPA = gpa;

}

// overrides the toString method in the parent class

public String toString(){

return super.toString() + ", student id: " + myIdNum + ", gpa: " + myGPA;

}

}

Assignment:

1. Save and compile the 2 programs shown above: Person.java for the Person class, Student.java for the Student class. These files should be used throughout this assignment.

2. 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.

3. 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.

4. 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

5. Show me the source code and run output. There should be one source file for each class: Teacher.java for the Teacher class, CollegeStudent.java for the CollegeStudent class, and BackToSchool.java for the BackToSchoolTester class. Make sure you have at least 8 persons included in your tester. Make sure you include Persons, Students, Teachers, and CollegeStudents Make sure you tester is NOT the same as any other student in our class.

LAB EXERCISE

BackToSchool

Background:

The HighSchool application described in the lesson 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) and major (e.g. "Electrical Engineering", "Communications", "Undeclared").

The inheritance hierarchy would appear as follows:

Here is the Person base class from the lesson to be used as a starting point for the Teacher class:

class Person{

private String myName ; // name of the person

private int myAge; // person's age

private 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 getName() {

return myName;

}

public int getAge(){

return myAge;

}

public String getGender(){

return myGender;

}

public void setName(String name){

myName = name;

}

public void setAge(int age) {

myAge = age;

}

public void setGender(String gender){

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{

private String myIdNum; // Student Id Number

private 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;

}

public String getIdNum(){

return myIdNum;

}

public double getGPA(){

return myGPA;

}

public void setIdNum(String idNum){

myIdNum = idNum;

}

public void setGPA(double gpa){

myGPA = gpa;

}

// overrides the toString method in the parent class

public String toString(){

return super.toString() + ", student id: " + myIdNum + ", gpa: " + myGPA;

}

}

Assignment:

1. Save and compile the 2 programs shown above: Person.java for the Person class, Student.java for the Student class. These files should be used throughout this assignment.

2. 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.

3. 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.

4. 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

5. Show me the source code and run output. There should be one source file for each class: Teacher.java for the Teacher class, CollegeStudent.java for the CollegeStudent class, and BackToSchool.java for the BackToSchoolTester class. Make sure you have at least 8 persons included in your tester. Make sure you include Persons, Students, Teachers, and CollegeStudents Make sure you tester is NOT the same as any other student in our class.