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| 22 | <title>Avoid Comma (GNU C Language Manual)</title>
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| 30 | <link href="Symbol-Index.html" rel="index" title="Symbol Index">
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| 31 | <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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| 32 | <link href="Comma-Operator.html" rel="up" title="Comma Operator">
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| 33 | <link href="Binary-Operator-Grammar.html" rel="next" title="Binary Operator Grammar">
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| 34 | <link href="Clean-Comma.html" rel="prev" title="Clean Comma">
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| 55 | </head>
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| 56 |
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| 57 | <body lang="en">
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| 58 | <span id="Avoid-Comma"></span><div class="header">
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| 59 | <p>
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| 60 | Previous: <a href="Clean-Comma.html" accesskey="p" rel="prev">Clean Comma</a>, Up: <a href="Comma-Operator.html" accesskey="u" rel="up">Comma Operator</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="When-Not-to-Use-the-Comma-Operator"></span><h4 class="subsection">8.5.3 When Not to Use the Comma Operator</h4>
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| 64 |
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| 65 | <p>You can use a comma in any subexpression, but in most cases it only
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| 66 | makes the code confusing, and it is clearer to raise all but the last
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| 67 | of the comma-separated expressions to a higher level. Thus, instead
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| 68 | of this:
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| 69 | </p>
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| 70 | <div class="example">
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| 71 | <pre class="example">x = (y += 4, 8);
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| 72 | </pre></div>
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| 73 |
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| 74 | <p>it is much clearer to write this:
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| 75 | </p>
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| 76 | <div class="example">
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| 77 | <pre class="example">y += 4, x = 8;
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| 78 | </pre></div>
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| 79 |
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| 80 | <p>or this:
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| 81 | </p>
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| 82 | <div class="example">
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| 83 | <pre class="example">y += 4;
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| 84 | x = 8;
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| 85 | </pre></div>
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| 86 |
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| 87 | <p>Use commas only in the cases where there is no clearer alternative
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| 88 | involving multiple statements.
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| 89 | </p>
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| 90 | <p>By contrast, don’t hesitate to use commas in the expansion in a macro
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| 91 | definition. The trade-offs of code clarity are different in that
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| 92 | case, because the <em>use</em> of the macro may improve overall clarity
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| 93 | so much that the ugliness of the macro’s <em>definition</em> is a small
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| 94 | price to pay. See <a href="Macros.html">Macros</a>.
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| 95 | </p>
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| 96 |
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| 97 |
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| 98 |
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| 99 | </body>
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| 100 | </html>
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