面向对象类之间的引用

今天写项目的时候写了一段程序，觉得挺有意思的。

<?php$t = new test();echo $t->msg;class test{public $msg;function test(){$this->msg = "aaaaa";$this->note = new note($this);$this->t_change_msg();}function t_change_msg(){$this->msg = "sssss";}}class note{public $test;function note($test) {$this->test = $test;$this->n_change_msg();}function n_change_msg(){$this->test->msg = "ddddd";return $this->test->msg;}}