PHP Const关键字

<?php
    //create class
    class lidihuo
    {
        //create constant variable
        const a= "this is const keyword example";
    }
//call constant variable.
echo lidihuo::a;
?>

<?php
    //create class
    class demo
    {
        //create constant variable
        const a= 10;
    }
//call constant variable.
echo demo::a;
?>