显示程序信息、版本号及版权所有。

Displays program information, version number and copyright.

youdao

显示程序信息，版本号和版权。

Display program information, version number and copyright.

youdao

你希望你的应用程序如何对某一个用户隐藏信息，而对另一个用户显示信息？

How do you want your application to hide information for one user and display it to another?

youdao

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