I've certainly written code that has this problem, I've tried to use my own code that has this problem, and good to us, right, good hygiene, I'm going to use that word again here, of getting into the habit of writing defensive code up front, it's part of that collection of things that you ought to do is a great thing to do.

我举手了吧？,我当然写过犯这种错误的程序了,我也尝试过应用含有这种错误的代码，不错，好的卫生，我还是要用这个词,对我们有帮助，养成写防卫性,代码的好习惯，是你应该做的,一系列事情之一,也是我们日后要做的主要的事情。

麻省理工公开课 - 计算机科学及编程导论课程节选

Most of the time, we're going to be doing expressions inside of some piece of code, inside of a script, which is the Python word for program.

大多数情况下，我们会在一些代码内部,写一些表达式，在一个脚本里面，也就是Python里面对程序的另一种叫法。

麻省理工公开课 - 计算机科学及编程导论课程节选

But what looks like this orange block as of now in Scratch, add orange to your so called inventory, well, it's gonna take at least two lines of code in C to actually create the inventory array with this first line and then put something like the word orange inside of it.

就好比Scratch里面橘色的这一块，把“桔子“加到所谓的“清单“里面去,在C语言中至少需要两行代码来实现,第一行代码创建一个货单数组,第二行就需要把“桔子“放进去。

哈佛公开课 - 计算机科学课程节选