<?php
//Syntax of define constant in php
//define(name, value, case-insensitive);
//it will print 100 in output
define('BOOK',100);
echo BOOK;
//it will print 200 in output
define('book', 200 , true);
echo book;
//results of all are the same
echo '<br>';
echo BOOK;
echo '<br>';
echo book;
