Class Constants in PHP
Once a constant is declared, it can’t be changed.
If you need to define some data that stays the same inside a class, you can use class constants.
The const keyword is used inside a class to declare a class constant.
Case matters when it comes to class constants as these are case-sensitiv. But it is best to name the constants with only capital letters.
We can use the class name, the scope resolution operator (::), and then the name of the constant to access it from outside the class, like this:
Example
<!DOCTYPE html>
<html>
<body><?php
class ending {
const LEAVING_MESSAGE = “Thank you for visit coderazaa.com!”;
}echo ending::LEAVING_MESSAGE;
?></body>
</html>
Output
Thank you for visit coderazaa.com!
Or, we can use the self keyword, the scope resolution operator (::), and then the name of the constant to access it from inside the class, like this:
Example
<!DOCTYPE html>
<html>
<body><?php
class ending {
const LEAVING_MESSAGE = “Thank you for visit coderazaa.com!”;
public function byebye() {
echo self::LEAVING_MESSAGE;
}
}$ending = new ending();
$ending->byebye();
?></body>
</html>
Output
Thank you for visit coderazaa.com!