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Now, how can I use code that someone else wrote?
那么，我们怎样才能用别人写的代码呢？
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In fact, this example would compile because you can use curly braces in this way to encapsulate lines of code, but realize for now, that, not good.
实际上，这个例子可以编译,因为你可以用这种方式来压缩代码行,但是请认识到，那个，不太好。
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In a high-level language, square root might simply be a primitive that you can use rather than you having to go over and code it.
一个高级的语言，平方根可能仅仅,只是你能使用的一个基本要素,而不是你需要去编译它。
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> That lets the compiler know that you want to use some actual compiled code from that library.
>，那是告诉编译器我们想要在程序库中,使用一些当前的编译后的代码。
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And to do this, I'm going to use some code that I've already typed in.
为了达到这个目的，我会去使用一些,我已经写好的代码。
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I want to just use it, I shouldn't have to worry about what variables I use inside of it, I have shouldn't have to worry about where that is in the code, I should be able to just abstract it away. And that's what we want to add today, are those two things.
我只是想使用它,我不用考虑我在这段代码中,使用的是什么变量,我完全不用考虑代码的内容,只要抽象就好,我们今天想补充的内容就是这两点。
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I'm going to use my own special program that will color code things for me in class, but the idea is the same; it's a text editor.
我将用我自己专门的程序,那个会分类为我标出代码的颜色，但是那个思想是一样的，这是一个文本编辑器。
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OK. All right, let me show you one other tool that I want to use. Which is, I've written that piece of code, I ought to check it. Well, I could just run it, but another useful thing to do is, I'm, especially as I want to debug these things, is to simulate that code.
好，那么，让我给大家讲下,我想用的另外一个工具吧,也就是，我已经写好了这一块代码，我应该去检查检查,那么我可以去运行它,但是特别是当我想要调试代码的时候。
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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。
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Now that I've written sqrt, I can just use it anywhere I want in the code. You've got to rely on the fact that I wrote it correctly, but you can basically suppress the details of how it's used.
就是忽略细节,既然我已经编写了sqrt函数,我可以在代码的任何地方使用它，你完全可以依靠,我已经编写的这个函数。
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But here, if I decide I'm going to store things not in x and y, but with some other set of names, for example, I've gotta go back into these pieces of code that use the points, and change them. So I've lost modularity.
除了要改下借口,但是这里，如果我决定，我不把值放在x和y中，而是和其他一些变量名进行绑定,例如这样的话,我就得回到使用这个点的代码，那儿去做更改了。
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So that is a flag that tells the compiler that I want to use or link into my own program code that someone else wrote that lives somewhere else on the system whose moniker is CS50.
所以那是一个标记，用来告诉编译器我想使用,或连接我自己的程序代码到一个叫做CS50的系统中的程序,可能其他人在那个系统写了这些程序。
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The standard library, that first line of code, it's not strictly necessary but any time you use a function, a tool that someone else wrote that lives in that so called library, you do need that include line as we'll see.
标准库函数--第一行代码，严格来说，不是每次都要写的，但是一旦你调用某个别人写，的函数，而这个函数又恰巧位于标准库里面,你就要像我们看到的这样，把它include进去。
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First of all, two parameters. It's OK. All it says is, when I call this, I need to pass in two parameters for this to work. All right? Now, if I want to use that, I'm going to use a second piece of code here, called Barnyard. I'm going Barnyard to read in a couple of values, convert them into integers, and then I'm going to use solve to get a solution out.
注意我得到了什么,第一，两个参数,它的意思就是我调用这个函数，我得给它输入两个参数，明白了吗？,现在如果我要使用它我得用,这里的第二段代码，也叫,我将读入一组值，将它们转化为整型,然后我会用solve得到一个解决方案。
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