246 lines
8.7 KiB
Plaintext
Generated
246 lines
8.7 KiB
Plaintext
Generated
<!DOCTYPE html>
|
|
<html>
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<title>Go by Example: Functions</title>
|
|
<link rel=stylesheet href="site.css">
|
|
</head>
|
|
<script>
|
|
onkeydown = (e) => {
|
|
|
|
if (e.key == "ArrowLeft") {
|
|
window.location.href = 'range';
|
|
}
|
|
|
|
|
|
if (e.key == "ArrowRight") {
|
|
window.location.href = 'multiple-return-values';
|
|
}
|
|
|
|
}
|
|
</script>
|
|
<body>
|
|
<div class="example" id="functions">
|
|
<h2><a href="./">Go by Example</a>: Functions</h2>
|
|
|
|
<table>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p><em>Functions</em> are central in Go. We’ll learn about
|
|
functions with a few different examples.</p>
|
|
|
|
</td>
|
|
<td class="code empty leading">
|
|
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
<a href="https://go.dev/play/p/-o49-dQfGbK"><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">
|
|
<p>Here’s a function that takes two <code>int</code>s and returns
|
|
their sum as an <code>int</code>.</p>
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma">
|
|
<span class="kd">func</span> <span class="nf">plus</span><span class="p">(</span><span class="nx">a</span> <span class="kt">int</span><span class="p">,</span> <span class="nx">b</span> <span class="kt">int</span><span class="p">)</span> <span class="kt">int</span> <span class="p">{</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>Go requires explicit returns, i.e. it won’t
|
|
automatically return the value of the last
|
|
expression.</p>
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma">
|
|
<span class="k">return</span> <span class="nx">a</span> <span class="o">+</span> <span class="nx">b</span>
|
|
<span class="p">}</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>When you have multiple consecutive parameters of
|
|
the same type, you may omit the type name for the
|
|
like-typed parameters up to the final parameter that
|
|
declares the type.</p>
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma">
|
|
<span class="kd">func</span> <span class="nf">plusPlus</span><span class="p">(</span><span class="nx">a</span><span class="p">,</span> <span class="nx">b</span><span class="p">,</span> <span class="nx">c</span> <span class="kt">int</span><span class="p">)</span> <span class="kt">int</span> <span class="p">{</span>
|
|
<span class="k">return</span> <span class="nx">a</span> <span class="o">+</span> <span class="nx">b</span> <span class="o">+</span> <span class="nx">c</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>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>Call a function just as you’d expect, with
|
|
<code>name(args)</code>.</p>
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma">
|
|
<span class="nx">res</span> <span class="o">:=</span> <span class="nf">plus</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</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">"1+2 ="</span><span class="p">,</span> <span class="nx">res</span><span class="p">)</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
|
|
</td>
|
|
<td class="code">
|
|
|
|
<pre class="chroma"> <span class="nx">res</span> <span class="p">=</span> <span class="nf">plusPlus</span><span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="mi">2</span><span class="p">,</span> <span class="mi">3</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">"1+2+3 ="</span><span class="p">,</span> <span class="nx">res</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 functions.go
|
|
<span class="go">1+2 = 3
|
|
</span><span class="go">1+2+3 = 6</span></pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>There are several other features to Go functions. One is
|
|
multiple return values, which we’ll look at next.</p>
|
|
|
|
</td>
|
|
<td class="code empty">
|
|
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
</table>
|
|
|
|
|
|
<p class="next">
|
|
Next example: <a href="multiple-return-values">Multiple Return Values</a>.
|
|
</p>
|
|
|
|
|
|
<p class="footer">
|
|
<script>
|
|
window.onload = function() {
|
|
function styleAllTags(tag, style, value){
|
|
document.querySelectorAll(tag).forEach((tag) => {
|
|
tag.style[style] = value
|
|
})
|
|
}
|
|
|
|
var themeButton = document.getElementById('theme-button');
|
|
var body = document.getElementsByTagName('body')[0];
|
|
|
|
var lightText = "#ffffffeb";
|
|
var darkText = "#252519";
|
|
var lightBackground = "white";
|
|
var darkBackground = "#1a202c";
|
|
var lightCodeBackground = "#f0f0f0";
|
|
var darkCodeBackground = "#333333";
|
|
|
|
|
|
function activateTheme(theme) {
|
|
if (theme === 'dark') {
|
|
body.style.color = lightText;
|
|
body.style.backgroundColor = darkBackground;
|
|
styleAllTags('a', 'color', lightText)
|
|
styleAllTags('td.code', 'background', darkCodeBackground);
|
|
styleAllTags('td.code.empty', 'background', darkBackground)
|
|
} else {
|
|
body.style.color = darkText;
|
|
body.style.backgroundColor = lightBackground;
|
|
styleAllTags('a', 'color', darkText)
|
|
styleAllTags('td.code', 'background', lightCodeBackground)
|
|
styleAllTags('td.code.empty', 'background', lightBackground)
|
|
}
|
|
localStorage.setItem('theme', theme);
|
|
}
|
|
|
|
var currentTheme = localStorage.getItem('theme');
|
|
if (currentTheme === 'light' || currentTheme === 'dark') {
|
|
activateTheme(currentTheme);
|
|
} else {
|
|
activateTheme('light');
|
|
}
|
|
|
|
themeButton.onclick = function() {
|
|
var newTheme = localStorage.getItem('theme') === 'dark' ? 'light' : 'dark';
|
|
activateTheme(newTheme);
|
|
}
|
|
}
|
|
</script>
|
|
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> and <a href="https://eli.thegreenplace.net">Eli Bendersky</a> | <a href="https://github.com/mmcgrana/gobyexample">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> | <button id="theme-button">Toggle theme</button>
|
|
</p>
|
|
|
|
</div>
|
|
<script>
|
|
var codeLines = [];
|
|
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import \"fmt\"\u000A');codeLines.push('func plus(a int, b int) int {\u000A');codeLines.push(' return a + b\u000A}\u000A');codeLines.push('func plusPlus(a, b, c int) int {\u000A return a + b + c\u000A}\u000A');codeLines.push('func main() {\u000A');codeLines.push(' res :\u003D plus(1, 2)\u000A fmt.Println(\"1+2 \u003D\", res)\u000A');codeLines.push(' res \u003D plusPlus(1, 2, 3)\u000A fmt.Println(\"1+2+3 \u003D\", res)\u000A}\u000A');codeLines.push('');codeLines.push('');
|
|
</script>
|
|
<script src="site.js" async></script>
|
|
</body>
|
|
</html>
|