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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::</span>setw</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-io.html">io</a>&lrm; | <a href="cpp-io-manip.html">manip</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-iomanip.html">&lt;iomanip&gt;</a></code></div>
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<div><span class="mw-geshi cpp source-cpp"><span class="coMULTI">/*unspecified*/</span> setw<span class="br0">(</span> <span class="kw4">int</span> n <span class="br0">)</span><span class="sy4">;</span></span></div>
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<p>&#29992;&#20110;&#34920;&#36798;&#24335; <span class="t-c"><span class="mw-geshi cpp source-cpp">out <span class="sy1">&lt;&lt;</span> setw<span class="br0">(</span>n<span class="br0">)</span></span></span> &#25110; <span class="t-c"><span class="mw-geshi cpp source-cpp">in <span class="sy1">&gt;&gt;</span> setw<span class="br0">(</span>n<span class="br0">)</span></span></span> &#26102;&#65292;&#35774;&#32622;&#27969; <code>out</code> &#25110; <code>in</code> &#30340; <code>width</code> &#21442;&#25968;&#20934;&#30830;&#20026; <code>n</code> &#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
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<td>n</td>
<td>-</td>
<td>width &#30340;&#26032;&#20540;</td>
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<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#36820;&#22238;&#26410;&#25351;&#23450;&#31867;&#22411;&#23545;&#35937;&#65292;&#28385;&#36275;&#33509; <code>str</code> &#26159; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-io-basic_ostream.html"><span class="kw1715">std::<span class="me2">basic_ostream</span></span></a><span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span></span></span> &#25110; <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-io-basic_istream.html"><span class="kw1713">std::<span class="me2">basic_istream</span></span></a><span class="sy1">&lt;</span>CharT, Traits<span class="sy1">&gt;</span></span></span> &#31867;&#22411;&#27969;&#30340;&#21517;&#31216;&#65292;&#21017;&#34920;&#36798;&#24335; <span class="t-c"><span class="mw-geshi cpp source-cpp">str <span class="sy1">&lt;&lt;</span> setw<span class="br0">(</span>n<span class="br0">)</span></span></span> &#25110; <span class="t-c"><span class="mw-geshi cpp source-cpp">str <span class="sy1">&gt;&gt;</span> setw<span class="br0">(</span>n<span class="br0">)</span></span></span> &#34920;&#29616;&#20026;&#22914;&#21516;&#25191;&#34892;&#19979;&#21015;&#20195;&#30721;&#65306;</p>
<p><span class="t-c"><span class="mw-geshi cpp source-cpp">str.<span class="me1">width</span><span class="br0">(</span>n<span class="br0">)</span><span class="sy4">;</span></span></span></p>
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">&#27880;&#24847;</span></h3>
<p>&#33509;&#35843;&#29992;&#20219;&#20309;&#19979;&#21015;&#20989;&#25968;&#65292;&#21017;&#27969;&#30340;&#23485;&#24230;&#23646;&#24615;&#23558;&#34987;&#35774;&#20026;&#38646;&#65288;&#34920;&#31034;&ldquo;&#19981;&#25351;&#23450;&rdquo;&#65289;&#65306;</p>
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<li>&#36755;&#20837;</li>
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<li><a href="cpp-string-basic_string-operator_ltltgtgt.html"><tt>operator&gt;&gt;(basic_istream&amp;, basic_string&amp;)</tt></a></li>
<li><a href="cpp-io-basic_istream-operator_gtgt2.html"><tt>operator&gt;&gt;(basic_istream&amp;, char*)</tt></a></li>
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<li>&#36755;&#20986;</li>
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<li><a href="cpp-io-basic_ostream-operator_ltlt.html"><tt>basic_ostream::operator&lt;&lt;()</tt></a> &#30340;&#37325;&#36733; 1-7 &#65288;&#22312; <a href="cpp-locale-num_put-put.html"><tt>num_put::put()</tt></a> &#30340;&#38454;&#27573; 3 &#65289;</li>
<li><a href="cpp-io-basic_ostream-operator_ltlt2.html"><tt>operator&lt;&lt;(basic_ostream&amp;, char)</tt></a> &#21644; <a href="cpp-io-basic_ostream-operator_ltlt2.html"><tt>operator&lt;&lt;(basic_ostream&amp;, char*)</tt></a></li>
<li><a href="cpp-string-basic_string-operator_ltltgtgt.html"><tt>operator&lt;&lt;(basic_ostream&amp;, basic_string&amp;)</tt></a></li>
<li><span class="t-lc"><a href="cpp-io-manip-put_money.html">std::put_money</a></span> &#65288;&#22312; <a href="cpp-locale-money_put-put.html"><tt>money_put::put()</tt></a> &#20869;&#65289;</li>
<li><span class="t-lc"><a href="cpp-io-manip-quoted.html">std::quoted</a></span> &#65288;&#20197;&#36755;&#20986;&#27969;&#20351;&#29992;&#26102;&#65289;</li>
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<p>&#27492;&#20462;&#25913;&#22120;&#22312;&#36755;&#20837;&#19982;&#36755;&#20986;&#19978;&#30340;&#20934;&#30830;&#25928;&#26524;&#22312;&#21333;&#29420;&#30340; I/O &#20989;&#25968;&#38388;&#26377;&#21035;&#65292;&#21333;&#29420;&#22320;&#25551;&#36848;&#20110;&#27599;&#20010; <code>operator&lt;&lt;</code> &#21508; <code>operator&gt;&gt;</code> &#37325;&#36733;&#30340;&#39029;&#38754;&#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;sstream&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;iomanip&gt;</span>
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
<span class="br0">{</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;no setw:&quot;</span> <span class="sy1">&lt;&lt;</span> <span class="nu0">42</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span>
<span class="sy1">&lt;&lt;</span> <span class="st0">&quot;setw(6):&quot;</span> <span class="sy1">&lt;&lt;</span> std<span class="sy4">::</span><span class="me2">setw</span><span class="br0">(</span><span class="nu0">6</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="nu0">42</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span>
<span class="sy1">&lt;&lt;</span> <span class="st0">&quot;setw(6), several elements: &quot;</span> <span class="sy1">&lt;&lt;</span> <span class="nu0">89</span> <span class="sy1">&lt;&lt;</span> std<span class="sy4">::</span><span class="me2">setw</span><span class="br0">(</span><span class="nu0">6</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="nu0">12</span> <span class="sy1">&lt;&lt;</span> <span class="nu0">34</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<a href="cpp-io-basic_istringstream.html"><span class="kw1735">std::<span class="me2">istringstream</span></span></a> is<span class="br0">(</span><span class="st0">&quot;hello, world&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">char</span> arr<span class="br0">[</span><span class="nu0">10</span><span class="br0">]</span><span class="sy4">;</span>
is <span class="sy1">&gt;&gt;</span> std<span class="sy4">::</span><span class="me2">setw</span><span class="br0">(</span><span class="nu0">6</span><span class="br0">)</span> <span class="sy1">&gt;&gt;</span> arr<span class="sy4">;</span>
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;Input from <span class="es1">\&quot;</span>&quot;</span> <span class="sy1">&lt;&lt;</span> is.<span class="me1">str</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;<span class="es1">\&quot;</span> with setw(6) gave <span class="es1">\&quot;</span>&quot;</span>
<span class="sy1">&lt;&lt;</span> arr <span class="sy1">&lt;&lt;</span> <span class="st0">&quot;<span class="es1">\&quot;</span><span class="es1">\n</span>&quot;</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">no setw:42
setw(6): 42
setw(6), several elements: 89 1234
Input from &quot;hello, world&quot; with setw(6) gave &quot;hello&quot;</pre></div>
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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="cpp-io-ios_base-width.html"><span class="t-lines"><span>width</span></span></a></div>
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<td>&#31649;&#29702;&#22495;&#30340;&#23485;&#24230;<br />
<span class="t-mark">(<code>std::ios_base</code> &#30340;&#20844;&#24320;&#25104;&#21592;&#20989;&#25968;)</span></td>
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<div><a href="cpp-io-manip-setfill.html"><span class="t-lines"><span>setfill</span></span></a></div>
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<td>&#26356;&#25913;&#22635;&#20805;&#23383;&#31526;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
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<div><a href="cpp-io-manip-left.html"><span class="t-lines"><span>internal</span><span>left</span><span>right</span></span></a></div>
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<td>&#35774;&#32622;&#22635;&#20805;&#23383;&#31526;&#30340;&#24067;&#32622;<br />
<span class="t-mark">(&#20989;&#25968;)</span></td>
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