请问一个类的设计有关问题
请教一个类的设计问题
我定一了一个父类 Catching
然后又定义了几个实现功能的类，每一个功能类 A() B（） Ｃ（） 都include了Catching类所在的文件并继承了
A extend Catching ………………
然后为了实现功能index.php 我需要用到 A B C 类
我就分别include引入了 A B C 类所在的文件。
现在我一运行，就提示有错误，说 Catching 从复定义
Cannot redeclare class Catching
还请高手指点一下，我那里设计错误了。
------解决方案--------------------
include_once
已加载就不加载
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