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<ol class="chapter"><li class="chapter-item expanded affix "><a href="title-page.html">Rust 程序设计语言</a></li><li class="chapter-item expanded affix "><a href="foreword.html">前言</a></li><li class="chapter-item expanded affix "><a href="ch00-00-introduction.html">简介</a></li><li class="chapter-item expanded "><a href="ch01-00-getting-started.html"><strong aria-hidden="true">1.</strong> 入门指南</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch01-01-installation.html"><strong aria-hidden="true">1.1.</strong> 安装</a></li><li class="chapter-item expanded "><a href="ch01-02-hello-world.html"><strong aria-hidden="true">1.2.</strong> Hello, World!</a></li><li class="chapter-item expanded "><a href="ch01-03-hello-cargo.html"><strong aria-hidden="true">1.3.</strong> Hello, Cargo!</a></li></ol></li><li class="chapter-item expanded "><a href="ch02-00-guessing-game-tutorial.html"><strong aria-hidden="true">2.</strong> 写个猜数字游戏</a></li><li class="chapter-item expanded "><a href="ch03-00-common-programming-concepts.html"><strong aria-hidden="true">3.</strong> 常见编程概念</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch03-01-variables-and-mutability.html"><strong aria-hidden="true">3.1.</strong> 变量与可变性</a></li><li class="chapter-item expanded "><a href="ch03-02-data-types.html"><strong aria-hidden="true">3.2.</strong> 数据类型</a></li><li class="chapter-item expanded "><a href="ch03-03-how-functions-work.html"><strong aria-hidden="true">3.3.</strong> 函数</a></li><li class="chapter-item expanded "><a href="ch03-04-comments.html" class="active"><strong aria-hidden="true">3.4.</strong> 注释</a></li><li class="chapter-item expanded "><a href="ch03-05-control-flow.html"><strong aria-hidden="true">3.5.</strong> 控制流</a></li></ol></li><li class="chapter-item expanded "><a href="ch04-00-understanding-ownership.html"><strong aria-hidden="true">4.</strong> 认识所有权</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch04-01-what-is-ownership.html"><strong aria-hidden="true">4.1.</strong> 什么是所有权？</a></li><li class="chapter-item expanded "><a href="ch04-02-references-and-borrowing.html"><strong aria-hidden="true">4.2.</strong> 引用与借用</a></li><li class="chapter-item expanded "><a href="ch04-03-slices.html"><strong aria-hidden="true">4.3.</strong> Slice 类型</a></li></ol></li><li class="chapter-item expanded "><a href="ch05-00-structs.html"><strong aria-hidden="true">5.</strong> 使用结构体组织相关联的数据</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch05-01-defining-structs.html"><strong aria-hidden="true">5.1.</strong> 结构体的定义和实例化</a></li><li class="chapter-item expanded "><a href="ch05-02-example-structs.html"><strong aria-hidden="true">5.2.</strong> 结构体示例程序</a></li><li class="chapter-item expanded "><a href="ch05-03-method-syntax.html"><strong aria-hidden="true">5.3.</strong> 方法语法</a></li></ol></li><li class="chapter-item expanded "><a href="ch06-00-enums.html"><strong aria-hidden="true">6.</strong> 枚举和模式匹配</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch06-01-defining-an-enum.html"><strong aria-hidden="true">6.1.</strong> 枚举的定义</a></li><li class="chapter-item expanded "><a href="ch06-02-match.html"><strong aria-hidden="true">6.2.</strong> match 控制流结构</a></li><li class="chapter-item expanded "><a href="ch06-03-if-let.html"><strong aria-hidden="true">6.3.</strong> if let 简洁控制流</a></li></ol></li><li class="chapter-item expanded "><a href="ch07-00-managing-growing-projects-with-packages-crates-and-modules.html"><strong aria-hidden="true">7.</strong> 使用包、Crate 和模块管理不断增长的项目</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="ch07-01-packages-and-crates.html"><strong aria-hidden="true">7.1.</strong> 包和 Crate</a></li><li class="chapter-item
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<h2 id="注释"><a class="header" href="#注释">注释</a></h2>
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<blockquote>
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<p><a href="https://github.com/rust-lang/book/blob/main/src/ch03-04-comments.md">ch03-04-comments.md</a>
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<br>
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commit d0acb2595c891de97a133d06635c50ab449dd65c</p>
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</blockquote>
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<p>所有程序员都力求使其代码易于理解，不过有时还需要提供额外的解释。在这种情况下，程序员在源码中留下 <strong>注释</strong>（<em>comments</em>），编译器会忽略它们，不过阅读代码的人可能觉得有用。</p>
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<p>这是一个简单的注释：</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>// hello, world
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<span class="boring">}</span></code></pre></pre>
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<p>在 Rust 中，惯用的注释样式是以两个斜杠开始注释，并持续到本行的结尾。对于超过一行的注释，需要在每一行前都加上 <code>//</code>，像这样：</p>
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<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">#![allow(unused)]
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</span><span class="boring">fn main() {
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</span>// So we’re doing something complicated here, long enough that we need
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// multiple lines of comments to do it! Whew! Hopefully, this comment will
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// explain what’s going on.
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<span class="boring">}</span></code></pre></pre>
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<p>注释也可以放在包含代码的行的末尾：</p>
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<p><span class="filename">文件名：src/main.rs</span></p>
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<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
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let lucky_number = 7; // I’m feeling lucky today
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}</code></pre></pre>
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<p>不过你更经常看到的是以这种格式使用它们，也就是位于它所解释的代码行的上面一行：</p>
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<p><span class="filename">文件名：src/main.rs</span></p>
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<pre><pre class="playground"><code class="language-rust edition2021">fn main() {
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// I’m feeling lucky today
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let lucky_number = 7;
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}</code></pre></pre>
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<p>Rust 还有另一种注释，称为文档注释，我们将在 14 章的 <a href="ch14-02-publishing-to-crates-io.html">“将 crate 发布到 Crates.io” </a>部分讨论它。</p>
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</div>
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<script>
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window.playground_copyable = true;
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<script src="elasticlunr.min.js"></script>
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<script src="mark.min.js"></script>
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<script src="searcher.js"></script>
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<script src="book.js"></script>
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<!-- Custom JS scripts -->
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<script src="ferris.js"></script>
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</div>
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</body>
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</html>
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