Its name is malloc for memory allocation and what malloc does for us is we say, hmm, the user has typed in a three-letter word.

它为我们分配内存地址,它为用户输入的3个字母单词,分配地址。

哈佛公开课 - 计算机科学课程节选

So, ask yourself frankly especially when it comes to designing your own tools and your own programs whether it's for real users to use, whether it's for your research group to use in some other field, you know, where do you even begin?

坦白讲，问一问你们自己,当你设计一个工具，一个程序时,它是否是为真实用户使用的，还是为在其他领域的,研究团队使用的，你们懂的，你从哪里开始？

哈佛公开课 - 计算机科学课程节选

But when you start writing programs, especially when we get to web-based stuff where you want -- to check the user's input -- is it valid, is it an email address, -- and all these different scenarios -- it's actually often useful to be able to just enumerate them or rattle them off using this switching construct instead.

但是当你看是写程序时，特别是当我们,使用基于网络的东西，你想要,检查用户的输入-,它是合法的吗？它是不是一个电子邮箱地址？,所有的这些场景-,实际上它常常是有用的，当你用枚举结构列举它们,或者用它来快速地来说出它们。

哈佛公开课 - 计算机科学课程节选

So if I type "man sleep," this is going to give me the user's manual for a program called sleep, but there's a gotcha and the problem set it makes clear, sleep notice that it says at top left sleep one.

所以如果我键入“man，sleep“，它将,给我一个叫做sleep程序的用户手册，但是这里有个参考信息，它使问题更清晰，请注意它指明在左上角。

哈佛公开课 - 计算机科学课程节选

So when you have a function called GetString, -- that means it's going to get a string from the user -- -- prompt the user for a string -- whereas printf is literally going to print it, not to paper, but to the screen.

所以当你有一个叫做GetSting的函数，它的意思是从用户那获得一个字符串-,提示用户输入一个字符串-,然而printf的确是用来打印的，不是在纸上，而是在屏幕上。

哈佛公开课 - 计算机科学课程节选

It's defined in CS50's library; its sole purpose in life is to ask the user for a floating point value and return it.

它被定义在CS50的函数库中，它的唯一目的是,向用户询问一个浮点数的值，然后返回它。

哈佛公开课 - 计算机科学课程节选

If you instead use GetString, same thing: blinking cursor, the function is just going to wait for the user to type a word, a sentence or whatever, and then hit Enter.

如果你用GetSring来代替它，同样的：闪烁光标，那个函数只是等待用户来,输入一个单词，一个句子什么的，然后敲回车。

哈佛公开课 - 计算机科学课程节选

Then I called GetInt, which is going to handle the difficult users for me.

然后我调用GetInt，它将,为我处理一些麻烦的用户。

哈佛公开课 - 计算机科学课程节选

So we'll talk a bit more about this idea of functions today, but, get int, again, can think of it as a black box, whose purpose in life is to prompt the human for input and pester the human if he or she doesn't actually give it int, but then once it has that, has entered it from the user, it's quote unquote, returns it to you.

所以我们进今天将多讨论点这个函数的概念，但是，GetInt，我们可以把它当做一个黑盒子，它的唯一目的是提示人们来输入,并且如果他或她没有,给它int数，则会纠缠用户，但是一旦它得到了，用户输入的int数，对输入进行引用，返回给你。

哈佛公开课 - 计算机科学课程节选

I'm going to use the CS50 Library instead for user input I'm saying say something then I'd get a string from the user and I call time s1 and then I say, say something, s2 and then I get another string from the user and call it s2 and apparently this program's purpose in life is to tell me yes or no the user said the same thing both times.

然而我使用的是CS50库来获得用户输入,我说点什么，然后从用户那里获得一个字符串,并把它叫做s1，然后我说点什么，然后从用户那里获得一个字符串，并把它叫做2,这个程序的最终目的是,告诉我两次用户输入的是不是同样的东西。

哈佛公开课 - 计算机科学课程节选

-- Else if n is greater than 4 and n is less than 6 -- 7 let's call it medium -- else if n is greater than or equal to 7, -- less than or equal to 10 -- let's call it "big" -- and if the user typed in zero or negative 10 or 20 or whatever, let's just use the all-inclusive else block and just say, "You picked an invalid number."

否则如果n大于4，并且n小于-,我们叫它为中间数--否则如果n大于等于，小于等于10--我们叫它为“大数“,如果用户键入了0或者-10或20或其它的，让我们用一个广泛的else子句，只需要说，“你选了一个非法的数字“

哈佛公开课 - 计算机科学课程节选