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methods.html
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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Go by Example 中文版: 方法</title>
<link rel=stylesheet href="site.css">
</head>
<script>
onkeydown = (e) => {
if (e.key == "ArrowLeft") {
window.location.href = 'structs';
}
if (e.key == "ArrowRight") {
window.location.href = 'interfaces';
}
}
</script>
<body>
<div class="example" id="methods">
<h2><a href="./">Go by Example 中文版</a>: 方法</h2>
<table>
<tr>
<td class="docs">
<p>Go 支持为结构体类型定义<em>方法(methods)</em> 。</p>
</td>
<td class="code empty leading">
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<a href="https://play.studygolang.com/p/uoV-yyZTV56"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kn">import</span> <span class="s">"fmt"</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">type</span> <span class="nx">rect</span> <span class="kd">struct</span> <span class="p">{</span>
<span class="nx">width</span><span class="p">,</span> <span class="nx">height</span> <span class="kt">int</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>这里的 <code>area</code> 是一个拥有 <code>*rect</code> 类型接收器(receiver)的方法。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">func</span> <span class="p">(</span><span class="nx">r</span> <span class="o">*</span><span class="nx">rect</span><span class="p">)</span> <span class="nf">area</span><span class="p">()</span> <span class="kt">int</span> <span class="p">{</span>
<span class="k">return</span> <span class="nx">r</span><span class="p">.</span><span class="nx">width</span> <span class="o">*</span> <span class="nx">r</span><span class="p">.</span><span class="nx">height</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>可以为值类型或者指针类型的接收者定义方法。
这是一个值类型接收者的例子。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="kd">func</span> <span class="p">(</span><span class="nx">r</span> <span class="nx">rect</span><span class="p">)</span> <span class="nf">perim</span><span class="p">()</span> <span class="kt">int</span> <span class="p">{</span>
<span class="k">return</span> <span class="mi">2</span><span class="o">*</span><span class="nx">r</span><span class="p">.</span><span class="nx">width</span> <span class="o">+</span> <span class="mi">2</span><span class="o">*</span><span class="nx">r</span><span class="p">.</span><span class="nx">height</span>
<span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
<span class="nx">r</span> <span class="o">:=</span> <span class="nx">rect</span><span class="p">{</span><span class="nx">width</span><span class="p">:</span> <span class="mi">10</span><span class="p">,</span> <span class="nx">height</span><span class="p">:</span> <span class="mi">5</span><span class="p">}</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>这里我们调用上面为结构体定义的两个方法。</p>
</td>
<td class="code leading">
<pre class="chroma">
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"area: "</span><span class="p">,</span> <span class="nx">r</span><span class="p">.</span><span class="nf">area</span><span class="p">())</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"perim:"</span><span class="p">,</span> <span class="nx">r</span><span class="p">.</span><span class="nf">perim</span><span class="p">())</span>
</pre>
</td>
</tr>
<tr>
<td class="docs">
<p>调用方法时，Go 会自动处理值和指针之间的转换。
想要避免在调用方法时产生一个拷贝，或者想让方法可以修改接受结构体的值，
你都可以使用指针来调用方法。</p>
</td>
<td class="code">
<pre class="chroma">
<span class="nx">rp</span> <span class="o">:=</span> <span class="o">&</span><span class="nx">r</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"area: "</span><span class="p">,</span> <span class="nx">rp</span><span class="p">.</span><span class="nf">area</span><span class="p">())</span>
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="s">"perim:"</span><span class="p">,</span> <span class="nx">rp</span><span class="p">.</span><span class="nf">perim</span><span class="p">())</span>
<span class="p">}</span>
</pre>
</td>
</tr>
</table>
<table>
<tr>
<td class="docs">
</td>
<td class="code leading">
<pre class="chroma"><span class="gp">$</span> go run methods.go
<span class="go">area: 50
</span><span class="go">perim: 30
</span><span class="go">area: 50
</span><span class="go">perim: 30</span></pre>
</td>
</tr>
<tr>
<td class="docs">
<p>接下来，我们将学习 Go 对方法集进行命名和分组的另一机制：接口。</p>
</td>
<td class="code empty">
</td>
</tr>
</table>
<p class="next">
下一个例子: <a href="interfaces.html">接口</a>
</p>
<p class="footer">
<a href="https://twitter.com/mmcgrana">@mmcgrana</a> 和<a href="https://eli.thegreenplace.net">Eli Bendersky</a>编写 | <a href="https://github.com/gobyexample-cn">gobyexample-cn</a> 翻译 | <a href="https://github.com/gobyexample-cn/gobyexample/issues">反馈</a> | <a href="https://github.com/gobyexample-cn/gobyexample">源码</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> </p>
</p>
</div>
<script>
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