ArrayQueue

package edu;

public class ArrayQueue {
	
	int[] queue;
	int front, rear, size;
	
	public ArrayQueue(int capacity) {
		queue = new int[capacity]; // initializing array and counter variable
		front = 0;
		rear = -1;
		size = 0;
	}
	
	public void enqueue(int data) {
		if(size == queue.length) {
			System.out.println("Queue is already full");
			return;
		}
		
		rear++;
		queue[rear] = data;
		size++;
	}
	
	public int dqueue() {
		if(size == 0) {
			System.out.println("Queue is already empty");
			return -1;
		}
		
		int removed = queue[front];
		front++;
		size--;
		return removed;
	}
	
	public void display() {
		for(int i=front;i<=rear;i++) {
			System.out.println(queue[i]);
		}
		System.out.println();
	}
	
	public static void main(String[] args) {
		ArrayQueue q = new ArrayQueue(5);
		
		q.enqueue(10);
		q.enqueue(20);
		q.enqueue(30);
		q.enqueue(40);
		q.display();
		
		q.dqueue();
		q.display();

	}

}