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| 22 | <title>Arithmetic (GNU C Language Manual)</title>
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| 33 | <link href="Basic-Arithmetic.html" rel="next" title="Basic Arithmetic">
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| 55 | </head>
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| 57 | <body lang="en">
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| 58 | <span id="Arithmetic"></span><div class="header">
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| 59 | <p>
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| 60 | Next: <a href="Assignment-Expressions.html" accesskey="n" rel="next">Assignment Expressions</a>, Previous: <a href="Lexical-Syntax.html" accesskey="p" rel="prev">Lexical Syntax</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</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="Arithmetic-1"></span><h2 class="chapter">6 Arithmetic</h2>
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| 64 | <span id="index-arithmetic-operators"></span>
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| 65 | <span id="index-operators_002c-arithmetic"></span>
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| 66 |
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| 67 |
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| 68 | <p>Arithmetic operators in C attempt to be as similar as possible to the
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| 69 | abstract arithmetic operations, but it is impossible to do this
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| 70 | perfectly. Numbers in a computer have a finite range of possible
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| 71 | values, and non-integer values have a limit on their possible
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| 72 | accuracy. Nonetheless, in most cases you will encounter no surprises
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| 73 | in using ‘<samp>+</samp>’ for addition, ‘<samp>-</samp>’ for subtraction, and ‘<samp>*</samp>’
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| 74 | for multiplication.
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| 75 | </p>
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| 76 | <p>Each C operator has a <em>precedence</em>, which is its rank in the
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| 77 | grammatical order of the various operators. The operators with the
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| 78 | highest precedence grab adjoining operands first; these expressions
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| 79 | then become operands for operators of lower precedence. We give some
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| 80 | information about precedence of operators in this chapter where we
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| 81 | describe the operators; for the full explanation, see <a href="Binary-Operator-Grammar.html">Binary Operator Grammar</a>.
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| 82 | </p>
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| 83 | <p>The arithmetic operators always <em>promote</em> their operands before
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| 84 | operating on them. This means converting narrow integer data types to
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| 85 | a wider data type (see <a href="Operand-Promotions.html">Operand Promotions</a>). If you are just
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| 86 | learning C, don’t worry about this yet.
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| 87 | </p>
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| 88 | <p>Given two operands that have different types, most arithmetic
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| 89 | operations convert them both to their <em>common type</em>. For
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| 90 | instance, if one is <code>int</code> and the other is <code>double</code>, the
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| 91 | common type is <code>double</code>. (That’s because <code>double</code> can
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| 92 | represent all the values that an <code>int</code> can hold, but not vice
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| 93 | versa.) For the full details, see <a href="Common-Type.html">Common Type</a>.
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| 94 | </p>
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| 95 | <table class="menu" border="0" cellspacing="0">
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| 96 | <tr><td align="left" valign="top">• <a href="Basic-Arithmetic.html" accesskey="1">Basic Arithmetic</a></td><td> </td><td align="left" valign="top">Addition, subtraction, multiplication,
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| 97 | and division.
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| 98 | </td></tr>
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| 99 | <tr><td align="left" valign="top">• <a href="Integer-Arithmetic.html" accesskey="2">Integer Arithmetic</a></td><td> </td><td align="left" valign="top">How C performs arithmetic with integer values.
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| 100 | </td></tr>
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| 101 | <tr><td align="left" valign="top">• <a href="Integer-Overflow.html" accesskey="3">Integer Overflow</a></td><td> </td><td align="left" valign="top">When an integer value exceeds the range
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| 102 | of its type.
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| 103 | </td></tr>
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| 104 | <tr><td align="left" valign="top">• <a href="Mixed-Mode.html" accesskey="4">Mixed Mode</a></td><td> </td><td align="left" valign="top">Calculating with both integer values
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| 105 | and floating-point values.
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| 106 | </td></tr>
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| 107 | <tr><td align="left" valign="top">• <a href="Division-and-Remainder.html" accesskey="5">Division and Remainder</a></td><td> </td><td align="left" valign="top">How integer division works.
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| 108 | </td></tr>
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| 109 | <tr><td align="left" valign="top">• <a href="Numeric-Comparisons.html" accesskey="6">Numeric Comparisons</a></td><td> </td><td align="left" valign="top">Comparing numeric values for equality or order.
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| 110 | </td></tr>
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| 111 | <tr><td align="left" valign="top">• <a href="Shift-Operations.html" accesskey="7">Shift Operations</a></td><td> </td><td align="left" valign="top">Shift integer bits left or right.
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| 112 | </td></tr>
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| 113 | <tr><td align="left" valign="top">• <a href="Bitwise-Operations.html" accesskey="8">Bitwise Operations</a></td><td> </td><td align="left" valign="top">Bitwise conjunction, disjunction, negation.
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| 114 | </td></tr>
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| 115 | </table>
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| 116 |
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| 117 | <hr>
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| 118 | <div class="header">
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| 119 | <p>
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| 120 | Next: <a href="Assignment-Expressions.html" accesskey="n" rel="next">Assignment Expressions</a>, Previous: <a href="Lexical-Syntax.html" accesskey="p" rel="prev">Lexical Syntax</a>, Up: <a href="index.html" accesskey="u" rel="up">Top</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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