How do you Implement a Queue using an ArrayList in java?

Answer 1

import java.util.*;

import java.io.*;

class PriorityQueue

{

int Q[];

int front,rear;

public PriorityQueue(int size)

{

rear=front=-1;

Q=new int[size];

}

public void offer(int val)

{

if((Q.length-1)>rear)

{

Q[++rear]=val;

System.out.println("offer elements in queue is"+ val);

}

else

{

front=rear=-1;

System.out.println("queue is overflow");

}

}

public void poll()

{

if(front==rear)

{

System.out.println("queue is empty");

}

else

{

System.out.println("poll element is"+ Q[++front]);

}

}

}

public class QueueDemo

{

public static void main(String[] args)

{

PriorityQueue Qu=new PriorityQueue(5);

Qu.offer(30);

Qu.offer(40);

Qu.offer(50);

Qu.offer(60);

Qu.poll();

Qu.poll();

}

}