Student.java

public 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;
  }
}