<?php    interface Computer {        public function version();        public function work();    }    class NoteComputer implements Computer {        public function version(){            echo ‘笔记本‘;        }        public function work(){            echo ‘可以便携运行WIN7！！‘;        }    }    class DesktopComputer implements Computer {        public function version(){            echo ‘台式机！‘;        }        public function work(){            echo ‘在工作站运行XP!‘;        }    }    class Person {        public function _run($type){            echo ‘这个人的‘;            $type->version();            $type->work();        }    }    //多态的原理就是，类都写好了~不要去修改它~只要在类外的调用参数更改    //最后的结果也会修改，那么这个就是多态    $notecomputer = new NoteComputer();    $desktopcomputer = new DesktopComputer();    $person = new Person();    $person->_run($notecomputer); //对象引用传递，持有对方的引用    echo ‘<br/>‘;    $person->_run($desktopcomputer);?>