PHP Constant
Last Updated: August 28, 2021
A constant is a variable except that once it is defined they cannot be changed or undefined.
Syntax
define(name, value, case-insensitive)
Parameters:
- name: You can specify the name of the constant
- value: You can specify the value of the constant
- case-insensitive: You can specify whether the constant name should be case-insensitive. Default is false (case sensitive)
Define value of Pi ( π ) in math :
<?php
define("PI", "3.14");
echo PI;
?>