Thread: Need Help With My Sorting and Arrays

Hello everyone, I still learning java so I'm still not familiar with how to call and how to change from different classes and using arrays but right now I'm trying to create a simple code like a school system where there show all the student name list with a grade in all the classes there are in using arrays object to store the data. I don't want to use ArrayList so NO ArrayList.

and it seems that I don't know how to do it. I'm really stuck right now can anyone help me with my code.

I WANT MY OUTPUT TO BE LIKE THIS:-

=== SCHOOL LISTS ===

1. Class Thunder with Total grade: 146
2. Class Lightning with Total grade: 103.9
3. Class Sunrise with Total grade: 115.5

--------------------
Class: Sunrise
Class quantity: 5

Student1: James Shawn
Grade: 75
Student2: Ali Pole
Grade: 30.5
Student3: Tong Kim
Grade: 10

Total Grade: 115.5
------------------------
Class: Thunder
Class quantity: 5

Student1: Mark Lee
Grade: 65.5
Student2: James Mic
Grade: 20.4
Student3: James Mic
Grade: 18.0

Total Grade: 103.9
------------------------
Class: Lightning
Class quantity: 5

Student1: Luke Kim
Grade: 90
Student2: Noth Shawn
Grade: 44
Student3: Lex Wale
Grade: 12

Total Grade: 146

Do you want to go back to the selection function?
Press Y or N:
//if yes they will go back to the functionSelection
//if no they will ask users if they want to exit the systems.

Do you want to exit (Y or N):

//if yes they will exit the systems
//if no they will go back to the functionSelection.

---------------------------------------------------------------------------------------------------------------------------------------

The class should have an array class of 10 sizes but initialize with 5 pre-team set.
and the student is only set to have 20 sizes (mean 20 students per class can't be more than the number set)

BELOW ARE MY CODE:-

STUDENT CLASS

import java.util.Comparator;
 
public class Student {
 
    private String studentName;
    private int grade;
 
    public Student(String studentName, int score) {
        this.studentName = studentName;
        this.grade = grade;
    }
 
    public String toString() {
        return "\nStudent Name: " + studentName + "\nGrade: " + grade;
    }
 
    public String getStudentName() {
        return studentName;
    }
 
    public int getGrade() {
        return grade;
    }
 
    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }
 
    public void setGrade(int grade) {
        this.grade = grade;
    }   
}
 
//Sorting side
class sortGrade implements Comparator<Student> {
 
        @Override
        public int compare(Student a, Student b) {
        return (a.getGrade() - b.getGrade());
    }
}

-----------------------------------------------------------------------
CLASS CLASS

public class Class {
 
    Student[] student;
    private String className;
    private int classQuantity;
    private int totalGrade = 0;
 
    //add student to the class
     public void addNewStudent(String studentName, double grade) {
 
    }
 
    public double calculateTotalGrade() {
 
        for (Student students : student) {
            totalGrade += students.getGrade();
        }
        return Math.round(totalGrade * 10.0) / 10.0;
    }
 
    public Class(Student[] student,
            String className, int classQuantity) {
 
        this.student = student;
        this.className = className;
        this.classQuantity = classQuantity;
    }
 
    public Class(String className, int classQuantity) {
 
        this.className = className;
        this.classQuantity = classQuantity;
    }
 
    public String toString() {
        String studentList = " ";
 
        for (int i = 0; i < student.length; i++) {
            studentList += "\n\tStudent " + (i + 1) + ": " + student[i].getStudentName()
                    + "\n\tGrade: " + student[i].getGrade();
        }
 
        return "\nClass Name: " + className
                + "\nClass Quantity: " + classQuantity + "\n" + studentList;
    }
}

--------------------------------------------------------------------------------------
MAIN DRIVER CLASS

import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
 
public class MainDriver {
 
    private Object[] a;
 
    void printSort(Student[] sortList) {
        for (Object sort : a) {
            System.out.print(sort + " ");
        }
        System.out.println();
    }
 
    public static void main(String[] args) {
 
        int size = 10;
        Class[] classroom = new Class[size];
 
        Student[] studentList1 = {
            new Student("Tong Kim", 10),
            new Student("Ali Pole", 30),
            new Student("James Shawn", 75)};
 
        Student[] studentList2 = {
            new Student("James Mic", 20),
            new Student("Ho Kim", 18),
            new Student("Mark Lee", 65)};
 
        Student[] studentList3 = {
            new Student("Luke Kim", 90),
             new Student("Noth Shawn", 44),
             new Student("Lex Wale", 12)
        };
 
        classroom[0] = new Class(studentList1, "Sunrise", 20);
        classroom[1] = new Class(studentList2, "Thunder", 10);
        classroom[2] = new Class(studentList3, "Lightning", 5);
 
        Scanner input = new Scanner(System.in);
        boolean functionSelection = true;
 
       // Student[] SortList = studentList1;
 
        while (functionSelection) {
 
            System.out.println("=== SCHOOL SYSTEM === \n");
            System.out.println("[1] Add New Class");
            System.out.println("[2] Exit");
 
            System.out.print("\nChoose a function: ");
 
            //Check if it is other then number
            if (!input.hasNextInt()) {
                System.out.println(" \nChoose the existing number");
                input.nextLine();
                continue;
            }
 
            int choice = input.nextInt();
 
            String newClassName, searchClass, newName, addName;
            switch (choice) {
                case 1:
 
                    //Show School List
                    /*List all class, student, grade and the total grade
                    in ascending*/
 
                    System.out.println("=== SCHOOL LIST ===");
 
                   Student[] SortList = studentList1;
 
                   //Descending Order Arrays
 
                    Comparator<Student> descendingOrder;
                    descendingOrder = Collections.reverseOrder
                    (new sortGrade());
 
                    Arrays.sort(SortList, descendingOrder);
                    System.out.println(Arrays.toString(SortList) + "\n");
                case 2: 
                    System.exit(0);
                    break;
                default:
                    System.out.println(" \nChoose the existing number");
            }
        }
    }
}

Please help me with my code