OK, so far though, I've just shown you what happens inside a peace a code. It raises an exception. It goes to that accept clause. We don't have to use it just inside of one place.

好了，我已经给你们看了,代码内部发生了什么,它报了一个异常，然后就到了处理的片段,我们不该就在一个地方用它。

麻省理工公开课 - 计算机科学及编程导论课程节选