PHP OOP – Class Constants
PHP allows to define constant data within a class, which value remains the same and unchangeable.
The default visibility of a class constant is public. A class constant is declared inside the class with the “const” keyword.
We can access a constant value from outside the class by using the class name followed by the scope resolution operator (::) followed by the constant name.
Let us understand with an example
<?php class Welcome { const WELCOME_MESSAGE= "Welcome to Share Query!"; } echo Welcome::WELCOME_MESSAGE; ?>
We can access a constant value from inside the class by using the self keyword followed by the scope resolution operator (::) followed by the constant name.
<?php class Welcome { const WELCOME_MESSAGE= "Welcome to Share Query!"; public function welcome_msg() { echo self::WELCOME_MESSAGE; } } $obj = new Welcome(); $obj->welcome_msg(); ?>