% Comments 注释

Now that we have some functions, it’s a good idea to learn about comments.Comments are notes that you leave to other programmers to help explain things about your code. The compiler mostly ignores them.

我们有了几个函数，了解注释是一个好主意。注释是标注在你将代码给其他程序员后，帮助他们理解你的代码的东西。编译器大都忽略他们。

Rust has two kinds of comments that you should care about: line comments and doc comments.

Rust有两种你需要关注的注释类型，行注释和块注释。

// Line comments are anything after ‘//’ and extend to the end of the line.

let x = 5; // this is also a line comment.

// If you have a long explanation for something, you can put line comments next
// to each other. Put a space between the // and your comment so that it’s
// more readable.

The other kind of comment is a doc comment. Doc comments use /// instead of //, and support Markdown notation inside:

另一种注释类是是块注释。块注释使用///替代//，并且支持Markdown符号

/// Adds one to the number given.
///
/// # Examples
///
/// ```
/// let five = 5;
///
/// assert_eq!(6, add_one(5));
/// ```
fn add_one(x: i32) -> i32 {
    x + 1
}

When writing doc comments, providing some examples of usage is very, very helpful. You’ll notice we’ve used a new macro here: assert_eq!. This compares two values, and panic!s if they’re not equal to each other. It’s very helpful in documentation. There’s another macro, assert!, which panic!s if the value passed to it is false.

当些块注释时，提供一些应用示例是非常非常有帮助的。你会注意到我们在这里使用了一个新的宏：assert_eq!。它对比两个值，并且在他们相互见不相等时产生panic!。在文档中它是非常有用的。这里还有另一个宏，assert!，如果传递给它的值是false，就会panic!。

You can use the rustdoc tool to generate HTML documentation from these doc comments, and also to run the code examples as tests!

你可以使用rustdoc工具从这些块注释来生成html文档注释，同样可以运行的代码例子作为测试！