Basic operations in Queues in PHP

basic-operations-in-queues-in-php.php

<?php

class Node
{
    public $value;
    public $next;

    public function __construct($value)
    {
        $this->value = $value;
        $this->next = null;
    }
}

class Queue
{
    public $first;
    public $last;
    public $length;

    public function __construct(public $value)
    {
        $newNode = new Node($value);
        $this->first = $newNode;
        $this->last = $newNode;
        $this->length = 1;
    }

    public function printQueue()
    {
        $temp = $this->first;
        while ($temp != null) {
            echo $temp->value."\n";
            $temp = $temp->next;
        }
    }

    public function enqueue($value)
    {
        $newNode = new Node($value);
        if ($this->length == 0) {
            $this->first = $newNode;
            $this->last = $newNode;
        } else {
            $this->last->next = $newNode;
            $this->last = $newNode;
        }
        $this->length++;
    }

    public function dequeue()
    {
        if ($this->length == 0) {
            return null;
        }
        $temp = $this->first;
        if ($this->length == 1) {
            $this->first = null;
            $this->last = null;
        } else {
            $this->first = $this->first->next;
            $temp->next = null;
        }
        $this->length--;
        return $temp;
    }

}

$q = new Queue("first customer");
$q->enqueue("second customer");
$q->enqueue("third customer");
$q->dequeue();
$q->printQueue();

// ARRAYS:
// $queue = [];
// array_push($queue, 'youtube.com');
// array_push($queue, 'google.com');
// array_push($queue, 'gmail.com');
// array_shift($queue);
// $queue;