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<div id="contentSub"><span class="subpages">&lt; <a href="c.html">c</a>&lrm; | <a href="c-numeric.html">numeric</a>&lrm; | <a href="c-numeric-complex.html">complex</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code>&lt;complex.h&gt;</code></div>
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<div><span class="mw-geshi c source-c"><span class="co2">#define I /* unspecified */</span></span></div>
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<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<p><code>I</code> &#23439;&#23637;&#24320;&#25104; <span class="t-lc"><a href="c-numeric-complex-Complex_I.html">_Complex_I</a></span> &#25110; <span class="t-lc"><a href="c-numeric-complex-Imaginary_I.html">_Imaginary_I</a></span> &#12290;&#33509;&#23454;&#29616;&#19981;&#25903;&#25345;&#34394;&#25968;&#31867;&#22411;&#65292;&#21017;&#35813;&#23439;&#22987;&#32456;&#23637;&#24320;&#25104; <span class="t-lc"><a href="c-numeric-complex-Complex_I.html">_Complex_I</a></span> &#12290;</p>
<p>&#19968;&#20010;&#31243;&#24207;&#21487;&#20197;&#21462;&#28040;&#23450;&#20041;&#65292;&#24182;&#33021;&#22312;&#32039;&#38543;&#20854;&#21518;&#37325;&#23450;&#20041;&#23439; <span class="t-c"><span class="mw-geshi c source-c">I</span></span> &#12290;</p>
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">&#27880;&#24847;</span></h3>
<p>&#35813;&#23439;&#21517;&#23383;&#19981;&#26159; <span class="t-c"><span class="mw-geshi c source-c">i</span></span> &#65292;&#34429;&#28982;&#36825;&#26159;&#25968;&#23398;&#19978;&#30340;&#34394;&#25968;&#21333;&#20301;&#21517;&#31216;&#12290;&#22240;&#20026; <code>i</code> &#24050;&#32463;&#29992;&#20110;&#22823;&#37327; C &#31243;&#24207;&#20013;&#65292;&#20363;&#22914;&#20316;&#20026;&#24490;&#29615;&#21464;&#37327;&#12290;</p>
<p>&#23439; <span class="t-c"><span class="mw-geshi c source-c">I</span></span> &#24120;&#29992;&#20110;&#32452;&#25104;&#22797;&#25968;&#65292;&#36890;&#36807;&#22914; <span class="t-c"><span class="mw-geshi c source-c">x <span class="sy2">+</span> y<span class="sy2">*</span>I</span></span> &#30340;&#34920;&#36798;&#24335;&#12290; &#33509; <code>I</code> &#34987;&#23450;&#20041;&#25104; <span class="t-lc"><a href="c-numeric-complex-Complex_I.html">_Complex_I</a></span> &#65292;&#21017;&#35813;&#34920;&#36798;&#24335;&#22312; <code>y</code> &#20026; <code>-0.0</code> &#26102;&#21019;&#24314;&#34394;&#37096;&#20026; <code>+0.0</code> &#30340;&#20540;&#65292;&#36825;&#23545;&#25317;&#26377;&#20998;&#25903;&#30340;&#22797;&#21464;&#20989;&#25968;&#26377;&#26174;&#33879;&#24433;&#21709;&#12290;&#23439; <span class="t-lc"><a href="c-numeric-complex-CMPLX.html">CMPLX</a></span> &#25552;&#20379;&#31934;&#30830;&#26500;&#36896;&#22797;&#25968;&#30340;&#26041;&#27861;&#12290;</p>
<p>GCC &#25552;&#20379;&#20102;&#19968;&#31181;&#19981;&#21487;&#31227;&#26893;&#30340;&#25193;&#23637;&#65292;&#23427;&#20801;&#35768;&#36890;&#36807;&#22312;&#23454;&#25968;&#23383;&#38754;&#37327;&#21518;&#25351;&#23450;&#21518;&#32512; <code>i</code> &#65306; <code>1.0fi</code> &#12289; <code>1.0i</code> &#21450; <code>1.0li</code> &#26159; GNU C &#20013;&#30340;&#34394;&#25968;&#21333;&#20301;&#12290; C++14 &#36215;&#65292;&#31867;&#20284;&#30340;&#26041;&#24335;&#26159;&#26631;&#20934; C++ &#30340;&#19968;&#37096;&#20998;&#65288; <code>1.0if</code> &#12289; <code>1.0i</code> &#21450; <code>1.0il</code> &#26159; C++ &#20013;&#30340;&#34394;&#25968;&#21333;&#20301;&#65289;&#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
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<pre class="de1"><span class="co2">#include &lt;stdio.h&gt;</span>
<span class="co2">#include &lt;complex.h&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">&quot;I = %.1f%+.1fi<span class="es1">\n</span>&quot;</span>, <a href="c-numeric-complex-creal.html"><span class="kw753">creal</span></a><span class="br0">(</span>I<span class="br0">)</span>, <a href="c-numeric-complex-cimag.html"><span class="kw750">cimag</span></a><span class="br0">(</span>I<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">double</span> <a href="c-numeric-complex-complex.html"><span class="kw743">complex</span></a> z1 <span class="sy1">=</span> I <span class="sy2">*</span> I<span class="sy4">;</span> <span class="co1">// &#34394;&#25968;&#21333;&#20301;&#24179;&#26041;</span>
<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">&quot;I * I = %.1f%+.1fi<span class="es1">\n</span>&quot;</span>, <a href="c-numeric-complex-creal.html"><span class="kw753">creal</span></a><span class="br0">(</span>z1<span class="br0">)</span>, <a href="c-numeric-complex-cimag.html"><span class="kw750">cimag</span></a><span class="br0">(</span>z1<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">double</span> <a href="c-numeric-complex-complex.html"><span class="kw743">complex</span></a> z <span class="sy1">=</span> <span class="nu16">1.0</span> <span class="sy2">+</span> <span class="nu16">2.0</span><span class="sy2">*</span>I<span class="sy4">;</span> <span class="co1">// &#22312; C11 &#21069;&#32452;&#25104;&#22797;&#25968;&#30340;&#36890;&#24120;&#36884;&#24452;</span>
<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">&quot;z = %.1f%+.1fi<span class="es1">\n</span>&quot;</span>, <a href="c-numeric-complex-creal.html"><span class="kw753">creal</span></a><span class="br0">(</span>z<span class="br0">)</span>, <a href="c-numeric-complex-cimag.html"><span class="kw750">cimag</span></a><span class="br0">(</span>z<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
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<p>&#36755;&#20986;&#65306;</p>
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<pre class="de1">I = 0.0+1.0i
I * I = -1.0+0.0i
z = 1.0+2.0i</pre></div>
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<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">&#24341;&#29992;</span></h3>
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<li>C11 &#26631;&#20934;&#65288;ISO/IEC 9899:2011&#65289;&#65306;</li>
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<li>7.3.1/6 I (p: 188)</li>
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<li>G.6/1 I (p: 537)</li>
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<li>C99 &#26631;&#20934;&#65288;ISO/IEC 9899:1999&#65289;&#65306;</li>
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<li>7.3.1/4 I (p: 170)</li>
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<li>G.6/1 I (p: 472)</li>
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<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
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<div><a href="c-numeric-complex-Imaginary_I.html"><span class="t-lines"><span>_Imaginary_I</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
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<td>&#34394;&#25968;&#21333;&#20301;&#24120;&#37327; i<br />
<span class="t-mark">(&#23439;&#24120;&#37327;)</span></td>
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<div><a href="c-numeric-complex-Complex_I.html"><span class="t-lines"><span>_Complex_I</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
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<td>&#22797;&#25968;&#21333;&#20301;&#24120;&#37327; i<br />
<span class="t-mark">(&#23439;&#24120;&#37327;)</span></td>
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<div><a href="c-numeric-complex-CMPLX.html"><span class="t-lines"><span>CMPLX</span><span>CMPLXF</span><span>CMPLXL</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div>
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<td>&#30001;&#23454;&#37096;&#21644;&#34394;&#37096;&#26500;&#24314;&#22797;&#25968;<br />
<span class="t-mark">(&#23439;&#20989;&#25968;)</span></td>
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