233 lines
17 KiB
HTML
233 lines
17 KiB
HTML
<!DOCTYPE html>
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<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>remainder, remainderf, remainderl</title>
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<link rel="stylesheet" href="site_modules.css" />
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_numeric_math_remainder skin-cppreference2 action-view cpp-navbar">
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<div id="cpp-content-base">
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<div id="content"><a id="top"></a>
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<h1 id="firstHeading" class="firstHeading">remainder, remainderf, remainderl</h1>
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<div id="bodyContent">
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<div id="contentSub"><span class="subpages">< <a href="c.html">c</a>‎ | <a href="c-numeric.html">numeric</a>‎ | <a href="c-numeric-math.html">math</a></span></div>
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<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
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<table class="t-dcl-begin">
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<td>
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<div>定义于头文件 <code><math.h></code></div>
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</td>
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<td></td>
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<td></td>
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<div><span class="mw-geshi c source-c"><span class="kw4">float</span> remainderf<span class="br0">(</span> <span class="kw4">float</span> x, <span class="kw4">float</span> y <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(1)</td>
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<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
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<tr class="t-dcl t-since-c99">
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<div><span class="mw-geshi c source-c"><span class="kw4">double</span> remainder<span class="br0">(</span> <span class="kw4">double</span> x, <span class="kw4">double</span> y <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(2)</td>
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<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
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</tr>
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<tr class="t-dcl t-since-c99">
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<td>
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<div><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">double</span> remainderl<span class="br0">(</span> <span class="kw4">long</span> <span class="kw4">double</span> x, <span class="kw4">long</span> <span class="kw4">double</span> y <span class="br0">)</span><span class="sy4">;</span></span></div>
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</td>
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<td>(3)</td>
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<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
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</tr>
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<tr class="t-dsc-header">
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<td>
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<div>定义于头文件 <code><tgmath.h></code></div>
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</td>
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<td></td>
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<td></td>
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<tr class="t-dcl t-since-c99">
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<td>
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<div><span class="mw-geshi c source-c"><span class="co2">#define remainder( x, y )</span></span></div>
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</td>
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<td>(4)</td>
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<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
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</tr>
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<tr class="t-dcl-sep">
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<td></td>
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<td></td>
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<td></td>
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</tr>
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</tbody>
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</table>
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<div class="t-li1"><span class="t-li">1-3@)</span> 计算浮点除法运算 <span class="t-c"><span class="mw-geshi c source-c">x<span class="sy2">/</span>y</span></span> 的 IEEE 余数。</div>
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<div class="t-li1"><span class="t-li">4)</span> 泛型宏：若任何参数拥有 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">double</span></span></span> 类型，则调用 <code>remainderl</code> 。否则若任何参数拥有整数类型或 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">double</span></span></span> 类型，则调用 <code>remainder</code> 。否则调用 <code>remainderf</code> 。</div>
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<p>此函数所计算的除法运算 <span class="t-c"><span class="mw-geshi c source-c">x<span class="sy2">/</span>y</span></span> 的 IEEE 浮点余数，准确地为值 <span class="t-c"><span class="mw-geshi c source-c">x <span class="sy2">-</span> n<span class="sy2">*</span>y</span></span> ，其中值 <code>n</code> 是最接近 <span class="t-c"><span class="mw-geshi c source-c">x<span class="sy2">/</span>y</span></span> 准确值的整数值。 <span class="texhtml" style="white-space: nowrap;">|n-x/y| = ½</span> 时，选择作为偶数的 <code>n</code> 。</p>
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<p>与 <span class="t-lc">std::fmod()</span> 相反，不保证返回值拥有与 <code>x</code> 相同的符号。</p>
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<p>若返回值是 <code>0</code> ，则它拥有与 <code>x</code> 相同的符号。</p>
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<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
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<table class="t-par-begin">
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<tr class="t-par">
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<td>x, y</td>
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<td>-</td>
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<td>浮点值</td>
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</tr>
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</table>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
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<p>若成功，则返回定义如上的除法 <span class="t-c"><span class="mw-geshi c source-c">x<span class="sy2">/</span>y</span></span> 浮点余数。</p>
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<p>若出现定义域错误，则返回实现定义值（受支持平台上为 NaN ）。</p>
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<p>若出现下溢所致的值域错误，则返回正确结果。</p>
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<p>若 <code>y</code> 为零但不出现定义域错误，则返回零。</p>
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<h3><span class="mw-headline" id=".E9.94.99.E8.AF.AF.E5.A4.84.E7.90.86">错误处理</span></h3>
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<p>报告 <a href="https://zh.cppreference.com/mwiki/index.php?title=math_errhandling&action=edit&redlink=1" class="new" title="math errhandling（页面不存在）"><tt>math_errhandling</tt></a> 中指定的错误。</p>
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<p>若 <code>y</code> 为零则可能出现定义域错误。</p>
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<p>若实现支持 IEEE 浮点算术 （ IEC 60559 ），则</p>
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<ul>
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<li>当前<a href="c-numeric-fenv-FE_round.html">舍入模式</a>无效。</li>
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<li>决不引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INEXACT</a></span> ，结果始终准确。</li>
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<li>若 <code>x</code> 为 ±∞ 且 <code>y</code> 非 NaN ，则返回 NaN 并引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INVALID</a></span> 。</li>
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<li>若 <code>y</code> 为 ±0 且 <code>x</code> 非 NaN ，则返回 NaN 并引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INVALID</a></span> 。</li>
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<li>若任一参数为 NaN ，则返回 NaN 。</li>
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</ul>
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<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
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<p><a rel="nofollow" class="external text" href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/remainder.html">POSIX 要求</a>若 <code>x</code> 为无穷大或 <code>y</code> 为零则出现定义域错误。</p>
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<p><code>fmod</code> ，但不是 <code>remainder</code> ，适于安静地包装浮点类型到无符号整数类型： <span class="t-c"><span class="mw-geshi c source-c"><span class="br0">(</span><span class="nu16">0.0</span> <span class="sy1"><=</span> <span class="br0">(</span>y <span class="sy1">=</span> <a href="c-numeric-math-fmod.html"><span class="kw647">fmod</span></a><span class="br0">(</span> <a href="c-numeric-math-rint.html"><span class="kw692">rint</span></a><span class="br0">(</span>x<span class="br0">)</span>, <span class="nu16">65536.0</span> <span class="br0">)</span><span class="br0">)</span> <span class="sy4">?</span> y <span class="sy4">:</span> <span class="nu16">65536.0</span> <span class="sy2">+</span> y<span class="br0">)</span></span></span> 在范围 <code>[-0.0 .. 65535.0]</code> 内，它对应 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">unsigned</span> <span class="kw4">short</span></span></span> ，但 <span class="t-c"><span class="mw-geshi c source-c">remainder<span class="br0">(</span><a href="c-numeric-math-rint.html"><span class="kw692">rint</span></a><span class="br0">(</span>x<span class="br0">)</span>, <span class="nu16">65536.0</span><span class="br0">)</span></span></span> 在范围 <code>[-32767.0, +32768.0]</code> 内，它在 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">signed</span> <span class="kw4">short</span></span></span> 的范围外。</p>
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<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
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<div class="t-example">
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<div class="t-example-live-link"></div>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="c source-c">
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<pre class="de1"><span class="co2">#include <stdio.h></span>
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<span class="co2">#include <math.h></span>
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<span class="co2">#include <fenv.h></span>
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<span class="co2">#pragma STDC FENV_ACCESS ON</span>
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<span class="kw4">int</span> main<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
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<span class="br0">{</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(+5.1, +3.0) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="nu16">5.1</span>,<span class="nu0">3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(-5.1, +3.0) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="sy2">-</span><span class="nu16">5.1</span>,<span class="nu0">3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(+5.1, -3.0) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="nu16">5.1</span>,<span class="sy2">-</span><span class="nu0">3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(-5.1, -3.0) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="sy2">-</span><span class="nu16">5.1</span>,<span class="sy2">-</span><span class="nu0">3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="co1">// 特殊值</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(-0.0, 1.0) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="sy2">-</span><span class="nu16">0.0</span>, <span class="nu0">1</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(+5.1, Inf) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="nu16">5.1</span>, INFINITY<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="co1">// 错误处理</span>
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<a href="c-numeric-fenv-feclearexcept.html"><span class="kw717">feclearexcept</span></a><span class="br0">(</span><a href="c-numeric-fenv-FE_exceptions.html"><span class="kw728">FE_ALL_EXCEPT</span></a><span class="br0">)</span><span class="sy4">;</span>
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<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">"remainder(+5.1, 0) = %.1f<span class="es1">\n</span>"</span>, remainder<span class="br0">(</span><span class="nu16">5.1</span>, <span class="nu0">0</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw718">fetestexcept</span></a><span class="br0">(</span><a href="c-numeric-fenv-FE_exceptions.html"><span class="kw731">FE_INVALID</span></a><span class="br0">)</span><span class="br0">)</span> <a href="c-io-puts.html"><span class="kw835">puts</span></a><span class="br0">(</span><span class="st0">" FE_INVALID raised"</span><span class="br0">)</span><span class="sy4">;</span>
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<span class="br0">}</span></pre></div>
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</div>
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<p>输出：</p>
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<div dir="ltr" class="mw-geshi" style="text-align: left;">
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<div class="text source-text">
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<pre class="de1">remainder(+5.1, +3.0) = -0.9
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remainder(-5.1, +3.0) = 0.9
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remainder(+5.1, -3.0) = -0.9
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remainder(-5.1, -3.0) = 0.9
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remainder(+0.0, 1.0) = 0.0
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remainder(-0.0, 1.0) = -0.0
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remainder(+5.1, Inf) = 5.1
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remainder(+5.1, 0) = -nan
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FE_INVALID raised</pre></div>
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</div>
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</div>
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<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">引用</span></h3>
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<div class="t-ref-std-11">
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<ul>
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<li>C11 标准（ISO/IEC 9899:2011）：</li>
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</ul>
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<dl>
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<dd>
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<ul>
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<li>7.12.10.2 The remainder functions (p: 254-255)</li>
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</ul>
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</dd>
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</dl>
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<dl>
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<dd>
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<ul>
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<li>7.25 Type-generic math <tgmath.h> (p: 373-375)</li>
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</ul>
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</dd>
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</dl>
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<dl>
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<dd>
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<ul>
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<li>F.10.7.2 The remainder functions (p: 529)</li>
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</ul>
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</dd>
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</dl>
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<div class="t-ref-std-c99">
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<ul>
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<li>C99 标准（ISO/IEC 9899:1999）：</li>
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</ul>
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<dl>
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<dd>
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<ul>
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<li>7.12.10.2 The remainder functions (p: 235)</li>
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</ul>
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</dd>
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</dl>
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<dl>
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<dd>
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<ul>
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<li>7.22 Type-generic math <tgmath.h> (p: 335-337)</li>
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</ul>
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</dd>
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</dl>
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<dl>
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<dd>
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<ul>
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<li>F.9.7.2 The remainder functions (p: 465)</li>
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</ul>
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</dd>
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</dl>
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</div>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
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<table class="t-dsc-begin">
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<tr class="t-dsc">
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<td>
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<div class="t-dsc-member-div">
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<div><a href="c-numeric-math-div.html"><span class="t-lines"><span>div</span><span>ldiv</span><span>lldiv</span></span></a></div>
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<div><span class="t-lines"><span></span><span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
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</div>
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</td>
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<td>计算整数除法的商和余数<br />
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<span class="t-mark">(函数)</span></td>
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</tr>
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<tr class="t-dsc">
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<td>
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<div class="t-dsc-member-div">
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<div><a href="c-numeric-math-fmod.html"><span class="t-lines"><span>fmod</span><span>fmodf</span><span>fmodl</span></span></a></div>
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<div><span class="t-lines"><span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
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</div>
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</td>
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<td>计算浮点除法运算的余数<br />
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<span class="t-mark">(函数)</span></td>
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</tr>
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<tr class="t-dsc">
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<td>
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<div class="t-dsc-member-div">
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<div><a href="c-numeric-math-remquo.html"><span class="t-lines"><span>remquo</span><span>remquof</span><span>remquol</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
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</div>
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</td>
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<td>计算除法运算的带符号余数，以及商的后三位<br />
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<span class="t-mark">(函数)</span></td>
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</tr>
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</table>
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</div>
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</div>
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<div class="visualClear"></div>
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</div>
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</div>
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</div>
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</body>
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</html>
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