//** Array Queue Structure */

class Queue {
  constructor() {
    this.items = [];
  }

  enqueue(element) {
    this.items.push(element);
  }

  dequeue() {
    return this.items.shift();
  }

  print() {
    return this.items.toString();
  }
  isEmpty() {
    return this.items.length === 0;
  }

  size() {
    return this.items.length;
  }
}

const queue = new Queue();

queue.enqueue(10);
queue.enqueue(20);
queue.enqueue(30);
queue.dequeue();
console.log(queue.print());
console.log(queue.size());