singlyqueue_example_basic

import javax.swing.*;
import java.util.Scanner;

public class singlyqueue_example_basic
{
    int arr[];
    int front,rear;
    singlyqueue_example_basic()
    {
        arr= new int [5];
        front=-1;
        rear=-1;
    }
    void insert()
    {
        if (rear== arr.length-1)
        {
            System.out.println("queue full");
        }
        else
        {
            System.out.println("enter data");
            Scanner sc = new Scanner(System.in);
            int data = sc.nextInt();

            if (front == -1)
            {
                front=0;
            }
            rear = rear+1;
            arr[rear] = data;
            System.out.println("data inserted");
        }
    }
    void delete()
    {
        if (front==-1)
        {
            System.out.println("queue empty");
        }
        else
        {
            System.out.println("deleted"+ arr[front]);
            if (front==rear)
            {
                front=-1;
                rear=-1;
            }
            else if(front<rear)
            {
                front=front+1;
            }
        }
    }
    void traverse()
    {
        if (front == -1 || rear == -1)
        {
            System.out.println("queue empty");
        }
        else
        {
            for(int i = front ; i <= rear ; i++)
            {
                System.out.print(" "+ arr[i]);
            }
        }
    }

    public static void main(String[] args) {
        singlyqueue_example_basic obj = new singlyqueue_example_basic();
        while (true)
        {
            System.out.println("\npress 1 for insert");
            System.out.println("press 2 for delete");
            System.out.println("press 3 for traverse");
            System.out.println("press 4 for exit");

            System.out.println("enter ur choice");
            Scanner sc = new Scanner(System.in);
            int choice = sc.nextInt();

            switch (choice)
            {
                case 1:
                    obj.insert();
                    break;
                case 2:
                    obj.delete();
                    break;
                case 3:
                    obj.traverse();
                    break;
                case 4:
                    System.exit(0);
                    break;
                default:
                    System.out.println("incorrect option");
            }
        }
    }
}