You can put a variable there, and because it's not encapsulated in curly braces, as we just discussed, that essentially means it's accessible everywhere in that file.

你可以加入一个变量，因为它不是封装在花括号里，就像我们刚才讨论的，本质的意思是它可以在文件的所有地方,都可以被访问到。

哈佛公开课 - 计算机科学课程节选

It solves a slight bug if we don't use it at all, but more on that in the future when you talk about files and creating files.

它解决了一点缺陷，如果我不用它，但是更多的是在以后当你们讨论,文件和创建文件时。

哈佛公开课 - 计算机科学课程节选