你应该想起来，我们是以一个，叫做二分法求平方根的问题结束的，它运用了二分法去求一个数的平方根，二分法和我们将要花很多时间。

This was using something called a bisection method, which is related to something called binary search, which we'll see lots more of later, to find square roots.

youdao

We knew this was trying to do squaring, so intellectually we know we can square -4, it ought to be 16, but what happens here?

我们知道程序是用来求平方数的，那么按理说我们可以来求-4的平方，也就是16，但是程序结果是怎么样的呢？

麻省理工公开课 - 计算机科学及编程导论课程节选

I'm given an integer that's a perfect square, and I want to write a little piece of code that's going to find the square root of it. All right so I'm cheating a little, I know it's a perfect square, somebody's given it to me, we'll come back in a second to generalizing it, so what would the steps be that I'd use to walk through it?

完美平方数的整数，我想写一段代码来求这个数的平方根,好，我这儿有点儿作弊了,我知道这是一个完美的平方数了,他们给我的，我们后面会讲怎么产生这个数的，那么我想解决这个问题,需要什么步骤呢？

麻省理工公开课 - 计算机科学及编程导论课程节选

And if I were to use that again, I'd just put it on your handout, I could go back and rewrite that thing that I had previously for finding the square roots of the perfect squares, just using the FOR loop. OK. What I want to do, though, is go on to-- or, sorry, go back to - my divisor example.

它可以是任意的集合,如果我又要去用这个方法的话,我会把它放在你们的课堂手册上的,我可以回过头去用FOR循环，重新写我们那个求平方数的程序，我想要做的是，是继续-哦抱歉,回到-我的除数那个例子。

麻省理工公开课 - 计算机科学及编程导论课程节选