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| <h3 class="section">20.2 Integer Division</h3> |
| |
| <p><a name="index-integer-division-functions-2325"></a> |
| This section describes functions for performing integer division. These |
| functions are redundant when GNU CC is used, because in GNU C the |
| ‘<samp><span class="samp">/</span></samp>’ operator always rounds towards zero. But in other C |
| implementations, ‘<samp><span class="samp">/</span></samp>’ may round differently with negative arguments. |
| <code>div</code> and <code>ldiv</code> are useful because they specify how to round |
| the quotient: towards zero. The remainder has the same sign as the |
| numerator. |
| |
| <p>These functions are specified to return a result <var>r</var> such that the value |
| <var>r</var><code>.quot*</code><var>denominator</var><code> + </code><var>r</var><code>.rem</code> equals |
| <var>numerator</var>. |
| |
| <p><a name="index-stdlib_002eh-2326"></a>To use these facilities, you should include the header file |
| <samp><span class="file">stdlib.h</span></samp> in your program. |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Data Type: <b>div_t</b><var><a name="index-div_005ft-2327"></a></var><br> |
| <blockquote><p>This is a structure type used to hold the result returned by the <code>div</code> |
| function. It has the following members: |
| |
| <dl> |
| <dt><code>int quot</code><dd>The quotient from the division. |
| |
| <br><dt><code>int rem</code><dd>The remainder from the division. |
| </dl> |
| </p></blockquote></div> |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Function: div_t <b>div</b> (<var>int numerator, int denominator</var>)<var><a name="index-div-2328"></a></var><br> |
| <blockquote><p>This function <code>div</code> computes the quotient and remainder from |
| the division of <var>numerator</var> by <var>denominator</var>, returning the |
| result in a structure of type <code>div_t</code>. |
| |
| <p>If the result cannot be represented (as in a division by zero), the |
| behavior is undefined. |
| |
| <p>Here is an example, albeit not a very useful one. |
| |
| <pre class="smallexample"> div_t result; |
| result = div (20, -6); |
| </pre> |
| <p class="noindent">Now <code>result.quot</code> is <code>-3</code> and <code>result.rem</code> is <code>2</code>. |
| </p></blockquote></div> |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Data Type: <b>ldiv_t</b><var><a name="index-ldiv_005ft-2329"></a></var><br> |
| <blockquote><p>This is a structure type used to hold the result returned by the <code>ldiv</code> |
| function. It has the following members: |
| |
| <dl> |
| <dt><code>long int quot</code><dd>The quotient from the division. |
| |
| <br><dt><code>long int rem</code><dd>The remainder from the division. |
| </dl> |
| |
| <p>(This is identical to <code>div_t</code> except that the components are of |
| type <code>long int</code> rather than <code>int</code>.) |
| </p></blockquote></div> |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Function: ldiv_t <b>ldiv</b> (<var>long int numerator, long int denominator</var>)<var><a name="index-ldiv-2330"></a></var><br> |
| <blockquote><p>The <code>ldiv</code> function is similar to <code>div</code>, except that the |
| arguments are of type <code>long int</code> and the result is returned as a |
| structure of type <code>ldiv_t</code>. |
| </p></blockquote></div> |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Data Type: <b>lldiv_t</b><var><a name="index-lldiv_005ft-2331"></a></var><br> |
| <blockquote><p>This is a structure type used to hold the result returned by the <code>lldiv</code> |
| function. It has the following members: |
| |
| <dl> |
| <dt><code>long long int quot</code><dd>The quotient from the division. |
| |
| <br><dt><code>long long int rem</code><dd>The remainder from the division. |
| </dl> |
| |
| <p>(This is identical to <code>div_t</code> except that the components are of |
| type <code>long long int</code> rather than <code>int</code>.) |
| </p></blockquote></div> |
| |
| <!-- stdlib.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Function: lldiv_t <b>lldiv</b> (<var>long long int numerator, long long int denominator</var>)<var><a name="index-lldiv-2332"></a></var><br> |
| <blockquote><p>The <code>lldiv</code> function is like the <code>div</code> function, but the |
| arguments are of type <code>long long int</code> and the result is returned as |
| a structure of type <code>lldiv_t</code>. |
| |
| <p>The <code>lldiv</code> function was added in ISO C99<!-- /@w -->. |
| </p></blockquote></div> |
| |
| <!-- inttypes.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Data Type: <b>imaxdiv_t</b><var><a name="index-imaxdiv_005ft-2333"></a></var><br> |
| <blockquote><p>This is a structure type used to hold the result returned by the <code>imaxdiv</code> |
| function. It has the following members: |
| |
| <dl> |
| <dt><code>intmax_t quot</code><dd>The quotient from the division. |
| |
| <br><dt><code>intmax_t rem</code><dd>The remainder from the division. |
| </dl> |
| |
| <p>(This is identical to <code>div_t</code> except that the components are of |
| type <code>intmax_t</code> rather than <code>int</code>.) |
| |
| <p>See <a href="Integers.html#Integers">Integers</a> for a description of the <code>intmax_t</code> type. |
| |
| </blockquote></div> |
| |
| <!-- inttypes.h --> |
| <!-- ISO --> |
| <div class="defun"> |
| — Function: imaxdiv_t <b>imaxdiv</b> (<var>intmax_t numerator, intmax_t denominator</var>)<var><a name="index-imaxdiv-2334"></a></var><br> |
| <blockquote><p>The <code>imaxdiv</code> function is like the <code>div</code> function, but the |
| arguments are of type <code>intmax_t</code> and the result is returned as |
| a structure of type <code>imaxdiv_t</code>. |
| |
| <p>See <a href="Integers.html#Integers">Integers</a> for a description of the <code>intmax_t</code> type. |
| |
| <p>The <code>imaxdiv</code> function was added in ISO C99<!-- /@w -->. |
| </p></blockquote></div> |
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