Create a Gradebook Class in Java

Problem:

Write a program that represents that Gradebook of the class Csc243.. The program takes the Grades of the students in the class till the user enters -1 to quit.. The main class must have a constructor for the course name and set and get methods, a displayMessage() to display the message and determineClassAverage() to calculate the average.. Although each grade is an integer, the averaging calculation is likely to produce a number with a decimal point, so this class uses a type double to do so. Then write a GradeBookTest and create GradeBook object and invoke its determineClassAverage method.

Output:

Welcome to the Grade book for
Csc 243 Introduction to Object Oriented Programming

Enter grade or -1 to quit: 97
Enter grade or -1 to quit: 88
Enter grade or -1 to quit: 72
Enter grade or -1 to quit: -1

Total of the 3 grades entered is 257
Class average is 85.65

Solution:

 import java.util.Scanner;
public class GradeBook
{
 private String name;
 private double sum,grade,average;
 private int count;
 
 public GradeBook (String name)
 {
  this.name = name;
 }
 public void setName(String name)
 {
  this.name = name;
 }
 public String getName() 
 {
  return name;
 }
 

 public String displayMessage()
 {
  String S = "Total of the " + count + 
            "grades entered is " + sum + "\n";
  S += "Class average is " + average;
  return S;
 }
 
 public double determineClassAverage()
 {
 while (grade != -1)
 {
 Scanner scan = new Scanner (System.in);
 System.out.print("Enter grade or -1 to quit: ");
 grade = scan.nextDouble();
 if (grade != -1) {
 sum += grade;
 count++; }
 }
 average = sum / count;
 return average;

 }
}

public class GradeBookTest
{
 public static void main (String[] args)
 {
  double grade = 0; double sum = 0; int count = 0;
  GradeBook grd1 = new GradeBook
      ("Csc 243 Introduction to Object Oriented Programming");
  
  System.out.println("Welcome to the Grade book for ");
  System.out.println(grd1.getName());
  System.out.println();
  grd1.determineClassAverage();
  System.out.println();
  System.out.println(grd1.displayMessage());
  
 }
}