BackToSchool

Background:

The HighSchool application described in the lesson has two classes: the Person superclass and the Student subclass. In this lab you will create two new classes, Teacher and CollegeStudent, using inheritance. 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", and "Other"). The CollegeStudent class will extend the Student class by adding a year (current level in college) and major (e.g. "Electrical Engineering", "Communications", and "Undeclared").

The inheritance hierarchy follows.

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

public 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;
  }
}

Assignment:

1. You will be provided with two source files as 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.

   1. Add instance variables to the class for subject (e.g. “Computer Science”, "Chemistry", "English", "Other”) and salary (the teacher’s annual salary). Subject should be of type String and salary of type double. Choose appropriate names for the instance variables.

   2. 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.

   3. Write “setter” and “getter” methods for all of the class variables. For the Teacher class they would be: getSubject, getSalary, setSubject, and setSalary.

   4. 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.

   1. 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.

   2. 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.

   3. Write “setter” and “getter” methods for all of the class variables. For the CollegeStudent class they would be: getYear, getMajor, setYear, and setMajor.

   4. 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