Right, and just to get a sense of this, let's look at a simple little example, so on your hand-out, you'll see I've got a little piece of code that says assuming I've got one of these points, I want to do things with it, for example I might want to add them together.

这些数组中的一个，你怎么能够知道，它是哪种类型的呢？,你怎么知道它是以笛卡尔坐标,表示的还是以极坐标,形式表示的呢？,你没有可以用来区分的东西，你没有说明这种信息,聚集实际上的意义。

麻省理工公开课 - 计算机科学及编程导论课程节选