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| 22 | <title>Numeric Comparisons (GNU C Language Manual)</title>
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| 31 | <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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| 32 | <link href="Arithmetic.html" rel="up" title="Arithmetic">
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| 57 | <body lang="en">
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| 58 | <span id="Numeric-Comparisons"></span><div class="header">
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| 59 | <p>
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| 60 | Next: <a href="Shift-Operations.html" accesskey="n" rel="next">Shift Operations</a>, Previous: <a href="Division-and-Remainder.html" accesskey="p" rel="prev">Division and Remainder</a>, Up: <a href="Arithmetic.html" accesskey="u" rel="up">Arithmetic</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="Numeric-Comparisons-1"></span><h3 class="section">6.6 Numeric Comparisons</h3>
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| 64 | <span id="index-numeric-comparisons"></span>
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| 65 | <span id="index-comparisons"></span>
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| 66 | <span id="index-operators_002c-comparison"></span>
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| 67 | <span id="index-equal-operator"></span>
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| 68 | <span id="index-not_002dequal-operator"></span>
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| 69 | <span id="index-less_002dthan-operator"></span>
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| 70 | <span id="index-greater_002dthan-operator"></span>
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| 71 | <span id="index-less_002dor_002dequal-operator"></span>
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| 72 | <span id="index-greater_002dor_002dequal-operator"></span>
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| 73 | <span id="index-operator_002c-equal"></span>
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| 74 | <span id="index-operator_002c-not_002dequal"></span>
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| 75 | <span id="index-operator_002c-less_002dthan"></span>
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| 76 | <span id="index-operator_002c-greater_002dthan"></span>
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| 77 | <span id="index-operator_002c-less_002dor_002dequal"></span>
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| 78 | <span id="index-operator_002c-greater_002dor_002dequal"></span>
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| 79 | <span id="index-truth-value"></span>
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| 80 |
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| 81 | <p>There are two kinds of comparison operators: <em>equality</em> and
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| 82 | <em>ordering</em>. Equality comparisons test whether two expressions
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| 83 | have the same value. The result is a <em>truth value</em>: a number that
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| 84 | is 1 for “true” and 0 for “false.”
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| 85 | </p>
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| 86 | <div class="example">
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| 87 | <pre class="example">a == b /* <span class="roman">Test for equal.</span> */
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| 88 | a != b /* <span class="roman">Test for not equal.</span> */
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| 89 | </pre></div>
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| 90 |
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| 91 | <p>The equality comparison is written <code>==</code> because plain <code>=</code>
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| 92 | is the assignment operator.
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| 93 | </p>
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| 94 | <p>Ordering comparisons test which operand is greater or less. Their
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| 95 | results are truth values. These are the ordering comparisons of C:
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| 96 | </p>
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| 97 | <div class="example">
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| 98 | <pre class="example">a < b /* <span class="roman">Test for less-than.</span> */
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| 99 | a > b /* <span class="roman">Test for greater-than.</span> */
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| 100 | a <= b /* <span class="roman">Test for less-than-or-equal.</span> */
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| 101 | a >= b /* <span class="roman">Test for greater-than-or-equal.</span> */
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| 102 | </pre></div>
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| 103 |
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| 104 | <p>For any integers <code>a</code> and <code>b</code>, exactly one of the comparisons
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| 105 | <code>a < b</code>, <code>a == b</code> and <code>a > b</code> is true, just as in
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| 106 | mathematics. However, if <code>a</code> and <code>b</code> are special floating
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| 107 | point values (not ordinary numbers), all three can be false.
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| 108 | See <a href="Special-Float-Values.html">Special Float Values</a>, and <a href="Invalid-Optimizations.html">Invalid Optimizations</a>.
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| 109 | </p>
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| 110 |
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| 111 |
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| 112 |
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| 113 | </body>
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