Now, what did I want to do? I wanted to check membership. I want to do search. Well that's simple. Given that representation and some value, I just say gee is it there?

现在，我需要做什么？,我要做成员检查，我要做查找,这就很简单了，给了即定的表示和一些值,我只需要说喂在那儿吗？

麻省理工公开课 - 计算机科学及编程导论课程节选

Well, the reason, the way that we can check it is just to see if it's in between our two extreme 1 cases. We know that it has to be more than 1, because even if we had total shielding, 1 we would at least feel is the effective of 1.

好的我们可以检查它的原因和方式是观察,它是否在我们的两种极端案例之间,我们知道它必须大于，因为即使如果我们有完全的屏蔽，我们最小感到的有效值是。

麻省理工公开课 - 化学原理课程节选

But notice what this does. The first thing it does is, it says, let's check and make sure x is greater than or equal to 0. If it isn't, notice what's going to happen. None of that block is going to get executed, and it's going to come down here and print out a useful piece of information, which says, hey, you gave me a negative number. I don't know how to do this.

做的是和以前一样的事情,但是注释它做了什么，第一件做的事情就是,程序说，要去检查并且确信x是大于等于0的，如果不是的话，请注意会发生什么,下面的代码都不会被执行,程序会到这里来然后显示一些有用的信息,信息会说，嘿，你给了我一个负数,我不知道该怎么弄这个了。

麻省理工公开课 - 计算机科学及编程导论课程节选