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| 58 | <span id="if_002delse-Statement"></span><div class="header">
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| 59 | <p>
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| 60 | Next: <a href="Blocks.html" accesskey="n" rel="next">Blocks</a>, Previous: <a href="if-Statement.html" accesskey="p" rel="prev">if Statement</a>, Up: <a href="Statements.html" accesskey="u" rel="up">Statements</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Index.html" title="Index" rel="index">Index</a>]</p>
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| 61 | </div>
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| 62 | <hr>
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| 63 | <span id="if_002delse-Statement-1"></span><h3 class="section">19.3 <code>if-else</code> Statement</h3>
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| 64 | <span id="index-if_2026else-statement"></span>
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| 65 | <span id="index-statement_002c-if_2026else"></span>
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| 66 | <span id="index-else"></span>
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| 67 |
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| 68 | <p>An <code>if</code>-<code>else</code> statement computes an expression to decide
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| 69 | which of two nested statements to execute.
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| 70 | It looks like this:
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| 71 | </p>
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| 72 | <div class="example">
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| 73 | <pre class="example">if (<var>condition</var>)
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| 74 | <var>if-true-substatement</var>
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| 75 | else
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| 76 | <var>if-false-substatement</var>
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| 77 | </pre></div>
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| 78 |
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| 79 | <p>The first thing this does is compute the value of <var>condition</var>. If
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| 80 | that is true (nonzero), then it executes the statement
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| 81 | <var>if-true-substatement</var>. If the value of <var>condition</var> is false
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| 82 | (zero), then it executes the statement <var>if-false-substatement</var> instead.
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| 83 | </p>
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| 84 | <p>This is a <em>complex statement</em> because it contains components
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| 85 | <var>if-true-substatement</var> and <var>if-else-substatement</var> that are
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| 86 | nested statements. Each must be one and only one statement. The way
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| 87 | to put multiple statements in such a component is to group them into a
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| 88 | <em>block</em> (see <a href="Blocks.html">Blocks</a>).
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| 89 | </p>
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| 90 |
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