In fact, as a little helper, notice what it's sort of automatically including for me: What's this thing here?

事实上，作为一个帮助程序，请注意,它为我自动分类：这个是什么东西？

哈佛公开课 - 计算机科学课程节选

And because there's nothing else in the code at that point, the program should just quit naturally in a good way. Yeah?

因为在那个阶段的没有其它的代码了，这个程序将以一种比较好的方式自然地退出，请说？

哈佛公开课 - 计算机科学课程节选

So let's look at a little example, and this is going to, excuse me, both allow us introduce the syntax as well as what we want to have as the flow of control inside of here.

让我们看个小例子，这个程序会，对不对，请允许我,一边顺着控制流进行,一边讲解语法。

麻省理工公开课 - 计算机科学及编程导论课程节选

So now notice this is almost the same program.

现在请注意，这几乎是同一个程序。

哈佛公开课 - 计算机科学课程节选

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