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<h1 class="title">Casting between types</h1>
<p><small>There is a new edition of the book and this is an old link.</small></p>
<blockquote>
<p>A type cast expression is denoted with the binary operator <code>as</code>.
Executing an <code>as</code> expression casts the value on the left-hand side to the type on the right-hand side.</p>
</blockquote>
<pre class="rust rust-example-rendered">
<span class="kw">fn</span> <span class="ident">average</span>(<span class="ident">values</span>: <span class="kw-2">&</span>[<span class="ident">f64</span>]) <span class="op">-></span> <span class="ident">f64</span> {
<span class="kw">let</span> <span class="ident">sum</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="ident">sum</span>(<span class="ident">values</span>);
<span class="kw">let</span> <span class="ident">size</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="ident">len</span>(<span class="ident">values</span>) <span class="kw">as</span> <span class="ident">f64</span>;
<span class="ident">sum</span> <span class="op">/</span> <span class="ident">size</span>
}<a class="test-arrow" target="_blank" href="https://play.rust-lang.org/?code=%23!%5Ballow(unused)%5D%0Afn%20main()%20%7B%0Afn%20sum(values%3A%20%26%5Bf64%5D)%20-%3E%20f64%20%7B%200.0%20%7D%0Afn%20len(values%3A%20%26%5Bf64%5D)%20-%3E%20i32%20%7B%200%20%7D%0A%0Afn%20average(values%3A%20%26%5Bf64%5D)%20-%3E%20f64%20%7B%0A%20%20%20%20let%20sum%3A%20f64%20%3D%20sum(values)%3B%0A%20%20%20%20let%20size%3A%20f64%20%3D%20len(values)%20as%20f64%3B%0A%20%20%20%20sum%20%2F%20size%0A%7D%0A%7D">Run</a></pre>
<hr />
<p>Here are the relevant sections in the new and old books:</p>
<ul>
<li><strong><a href="second-edition/appendix-01-keywords.html">In the second edition: Appendix A — Keywords</a></strong></li>
<li><a href="../reference/expressions/operator-expr.html#type-cast-expressions">In the Rust Reference: Type Cast Expressions</a></li>
<li><a href="../std/mem/fn.transmute.html">In the Rust documentation: <code>mem::transmute</code></a></li>
<li><small><a href="first-edition/casting-between-types.html">In the first edition: Ch 3.29 — Casting between types</a></small></li>
</ul>
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