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After go1.16, go will use module mode by default, even when the repository is checked out under GOPATH or in a one-off directory. Add go.mod, go.sum to keep this repo buildable without opting out of the module mode. > go mod init github.com/mmcgrana/gobyexample > go mod tidy > go mod vendor In module mode, the 'vendor' directory is special and its contents will be actively maintained by the go command. pygments aren't the dependency the go will know about, so it will delete the contents from vendor directory. Move it to `third_party` directory now. And, vendor the blackfriday package. Note: the tutorial contents are not affected by the change in go1.16 because all the examples in this tutorial ask users to run the go command with the explicit list of files to be compiled (e.g. `go run hello-world.go` or `go build command-line-arguments.go`). When the source list is provided, the go command does not have to compute the build list and whether it's running in GOPATH mode or module mode becomes irrelevant.
133 lines
4.3 KiB
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133 lines
4.3 KiB
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<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Go by Example: Recursion</title>
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<link rel=stylesheet href="site.css">
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</head>
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<script>
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onkeydown = (e) => {
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if (e.key == "ArrowLeft") {
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window.location.href = 'closures';
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}
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if (e.key == "ArrowRight") {
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window.location.href = 'pointers';
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}
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}
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</script>
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<body>
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<div class="example" id="recursion">
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<h2><a href="./">Go by Example</a>: Recursion</h2>
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<table>
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<tr>
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<td class="docs">
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<p>Go supports
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<a href="http://en.wikipedia.org/wiki/Recursion_(computer_science)"><em>recursive functions</em></a>.
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Here’s a classic factorial example.</p>
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</td>
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<td class="code empty leading">
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<a href="http://play.golang.org/p/smWim1q9ofu"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
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<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kn">import</span> <span class="s">"fmt"</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>This <code>fact</code> function calls itself until it reaches the
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base case of <code>fact(0)</code>.</p>
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</td>
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<td class="code leading">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">fact</span><span class="p">(</span><span class="nx">n</span> <span class="kt">int</span><span class="p">)</span> <span class="kt">int</span> <span class="p">{</span>
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<span class="k">if</span> <span class="nx">n</span> <span class="o">==</span> <span class="mi">0</span> <span class="p">{</span>
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<span class="k">return</span> <span class="mi">1</span>
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<span class="p">}</span>
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<span class="k">return</span> <span class="nx">n</span> <span class="o">*</span> <span class="nx">fact</span><span class="p">(</span><span class="nx">n</span><span class="o">-</span><span class="mi">1</span><span class="p">)</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code">
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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nx">Println</span><span class="p">(</span><span class="nx">fact</span><span class="p">(</span><span class="mi">7</span><span class="p">))</span>
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<span class="p">}</span>
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</pre></div>
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</td>
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</tr>
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</table>
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<table>
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<tr>
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<td class="docs">
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</td>
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<td class="code">
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<div class="highlight"><pre><span class="gp">$</span> go run recursion.go
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<span class="go">5040</span>
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</pre></div>
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</td>
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</tr>
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</table>
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<p class="next">
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Next example: <a href="pointers">Pointers</a>.
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</p>
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<p class="footer">
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by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/recursion">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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</p>
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</div>
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<script>
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var codeLines = [];
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codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import \"fmt\"\u000A');codeLines.push('func fact(n int) int {\u000A if n \u003D\u003D 0 {\u000A return 1\u000A }\u000A return n * fact(n-1)\u000A}\u000A');codeLines.push('func main() {\u000A fmt.Println(fact(7))\u000A}\u000A');codeLines.push('');
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</script>
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<script src="site.js" async></script>
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</body>
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</html>
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