Queue [data type]

queue.php

<?php

class Queue
{
    /**
     * Items
     *
     * @var array
     */
    protected $items = [];

    /**
     * Enqueue
     *
     * @param mixed $value
     * @return void
     */
    public function enqueue($value)
    {
        $this->items[] = $value;
    }

    /**
     * Dequeue
     *
     * @return mixed
     * @throws Exception
     */
    public function dequeue()
    {
        if (!$this->items) {
            throw new Exception('There are no any items in queue');
        }

        $currentItemValue = current($this->items);
        unset($this->items[key($this->items)]);

        return $currentItemValue;
    }
}

$queue = new Queue();

// fill the queue
foreach (range(0, 15) as $value) {
    $queue->enqueue($value);
}


// extract from the queue
foreach (range(0, 15) as $value) {
    echo $queue->dequeue() . '<br>';
}