Friday, July 3, 2015


Java GradeBook Program Using Instance Variables

The program below is the answer to Deitel's Java How to Program (9th Edition) Chapter 3 Exercise 3.11.

Question: Modify class GradeBook (Fig. 3.10) as follows:
  1. Include a String instance variable that represents the name of the course’s instructor.
  2. Provide a set method to change the instructor’s name and a get method to retrieve it.
  3. Modify the constructor to specify two parameters — one for the course name and one for the instructor’s name.
  4. Modify method displayMessage to output the welcome message and course name, followed by "This course is presented by: " and the instructor’s name.
Use your modified class in a test application that demonstrates the class’s new capabilities.

To run the application save both files with the same name as the class (because it is a public class) and with the .java file extension (in this case and Then compile both classes  and run Ex03_11_Test. Ex03_11 will not run because it does not have a main method.

To compile both classes at the same time using the command prompt, use the command

To run Ex03_11_Test, use the command
java Ex03_11_Test

 * @Author: Aghatise Osazuwa
 * Website:
 * Exercise 3.11 - Modified GradeBook Class
 * This Program Modifies Class GradeBook (Fig. 3.10) In The Book To Display
 * Course Name And Instructor's Name

 public class Ex03_11 {
     private String courseName; 
     private String instructorName; 
     public Ex03_11 (String name, String insName) {
         courseName = name;
         instructorName = insName;
     public void setCourseName (String name) {
         courseName = name;
     public String getCourseName () {
         return courseName;
     public void setInstructorsName (String insName) {
         instructorName = insName;
     public String getInstructorName () {
         return instructorName;
     public void displayMessage () {
         System.out.printf ("Welcome to the gradebook for: %s!\nThis course is "
                   + "presented by: %s\n", getCourseName (), getInstructorName ());


Below is Class to test class Ex03_11

//Exercise 3.11 - Modified GradeBook Class Test
//This Program Tests Ex03_11 To Demonstrate The Class’s Capabilities

import java.util.Scanner;

public class Ex03_11_Test {
        public static void main (String [] args) {
            Ex03_11 mygradebook = new Ex03_11 ("Course Name", "Instructor's Name");

     Scanner input = new Scanner (;
            System.out.print ("Enter Your Course Name: ");
            String name = input.nextLine();
            System.out.print ("Enter Your Course Instructor's Name: ");
            String insName = input.nextLine();
            System.out.println ();


Click here to see other answers to Java How to Program.


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