How can i implement QUEUE in PHP?

In the circular queue, we can use an empty data cell again when we remove the cell value using a dequeue. Another important thing is we can not add value before the end of the head index( for example, if my array size is 5 and the head point to an index of 0, then we need to empty the array index 4. Which means we can add 4 value when the array size is 5). We can use this queue implementation in banking software( ex: give tokens to customers and call them according to that token). Here is the complete code below:

$devisor  = 5;
$data_array = [];
$head = 0;
$tail = 0;

function enqueue( $item = NULL ){
	global $head, $tail, $data_array, $devisor;
	if(empty($item)){
		echo 'invalid function call. Need to pass item as a function parametter';
		return;
	}
	$tail = $tail % $devisor;
	$next_tindex = $tail + 1;
	if( $head == $next_tindex % $devisor){
		echo 'Queue is full';
		return;
	}else{
		$data_array[$tail] = $item;
		$tail++;
	}
	return $data_array;
}

function dequeue(){
	global $head,$tail,$devisor,$data_array;
	if($tail == $head){
		echo 'Queue is empty';
		return -1;
	}
	
	$item = $data_array[$head];
	$head = ++$head % $devisor;
	return $item;
}

echo '<pre>';
print_r(enqueue(1));
echo '</pre>';
echo '<pre>';
print_r(dequeue());
echo '</pre>';

Plugins to Enhance Your WooCommerce Store

Carefully selected tools to help you customize, manage, and optimize your WooCommerce experience.

Woo Parent Category Selector

• Automatically assign parent categories when child categories are selected
• Prevent accidental removal of required parent categories
• Automatically repairs missing parent category assignments during product save
• Bulk repair existing WooCommerce product category structures
• Keeps product category structures organized and consistent

Learn More

Product Catalog Mode For WooCommerce

• Turn your WooCommerce store into catalog mode instantly
• Hide Add to Cart buttons and product prices conditionally
• Apply rules by user role, country, or scheduled time periods
• Display custom messages and inquiry options for products
• Control visibility settings globally or per product

Learn More View on WordPress.org

Remove Add to Cart Button for WooCommerce

• Remove Add to Cart buttons from shop and product pages
• Hide buttons conditionally for selected products or categories
• Replace Add to Cart with custom text or messages
• Control button visibility by user role and product type
• Lightweight settings interface with easy customization

Learn More View on WordPress.org

Remove Product Content for WooCommerce

• Hide product title, image, price, rating, and descriptions
• Remove tabs, meta information, SKU, tags, and related products
• Control visibility separately for shop and single product pages
• Customize WooCommerce layouts without coding
• Enable or disable content elements with simple settings

Learn More View on WordPress.org

Really Simple XML and HTML Sitemap

• Generate both XML and HTML sitemaps automatically
• Display sitemaps anywhere using ShortCode support
• Include pages, posts, and custom post types
• Exclude selected pages or posts easily
• Supports WPML and Polylang multilingual plugins

Learn More View on WordPress.org