<?php
    function zhang(){
        echo "My name is zhang, \n";
    }
    function noname($name){
      echo "My name is $name, \n ";
     }
    $show = 'zhang';
    $show();      //这与写 zhang()一样；
    $show = 'noname';
    $show(Harry);   // 这与编写noname('Harry') 一样；
?>