Queue

import java.util.Scanner;
public class Queue 
{
	static Scanner sc=new Scanner(System.in);
	static int n,front=-1, rear=-1,item;
	static int[] Ar=new int[10];
	
	Queue()
	{
		
	}
	Queue(int n)
	{
		int ch;
		do
		{
			System.out.println("1. Enqueue\n 2. Dequeue\n 3.Display\n");
			System.out.println("enter your choice\n");
			ch=sc.nextInt();
			switch(ch)
			{
			case 1:
				enqueue(n);
				break;
			case 2:
				dequeue(n);
				break;
			case 3:
				display(n);
				break;
			default:
				break;
			}
		}
		while(ch<3);
	}
	public static void main(String[] args)
	{
		Scanner sc1=new Scanner(System.in);
		int n;
		System.out.println("Enter the size of queue");
		n=sc1.nextInt();
		new Queue(n);
	}
	public static void enqueue(int n)
	{
		if(rear>= n-1)
			System.out.println("overflow");
		else
			if(front==-1 && rear==-1)
			{
				front++;
			}
			System.out.println("enter the element to be inserted\n");
			item=sc.nextInt();
			rear++;
			Ar[rear]=item;
			display(rear);
 }
	public static void dequeue(int n)
	{
		if(front==-1)
			System.out.println("underflow\n");
		else
		{
			item=Ar[front];
			System.out.printf("the element deleted is %d \n",item);
			if(front==rear)
			{
				front=-1;
				rear=-1;
				System.out.println("the queue is empty");
			}
			else
				front++;
			    display(rear);
			}
		}
	public static void display(int rear)
	{
		int i;
		System.out.println("the current queue is\n");
		for(i=front;i<=rear;i++)
		{
			System.out.printf("%d",Ar[i]);
		}
		System.out.println("\n");
	}

}