Now just to get used to the conventions, 0 because this is the program you'll use not for problems at 0 but for 1 to start writing programs, notice at the top in this window just reminds you what you're working on.

我们要入乡随俗，习惯这样的界面，因为这是你们将要用到的程序，不是为习题集0，而是0,而是为习题集1开始写程序的,注意窗口顶部，这是用来提醒你，你工作在何种环境。

哈佛公开课 - 计算机科学课程节选