class Product { static $count = 0; public function __construct() { self::$count++; } public function getCount() { return self::$count; } }
class Math { public static function add($a, $b) { return $a + $b; } }
class Config { public static $data = array( 'app_name' => 'MyApp', 'db_host' => 'localhost', 'db_user' => 'root', 'db_pass' => 'password', 'db_name' => 'myapp_db' ); public static function get($key) { return self::$data[$key]; } }In this example, the static key is used to declare a class-level property `$data`. The `get()` method returns the value of a specific key from the `$data` array. Package library: No specific package library is required for using static key in PHP. Overall, the static key in PHP is a useful tool for declaring variables, methods, and properties that can be accessed without creating an instance of the class. It can be used in various scenarios and does not require any specific package library.