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<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::ranges::</span>clamp</h1>
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<div id="contentSub"><span class="subpages">&lt; <a href="cpp.html">cpp</a>&lrm; | <a href="cpp-algorithm.html">algorithm</a>&lrm; | <a href="cpp-algorithm-ranges.html">ranges</a></span></div>
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code><a href="cpp-header-algorithm.html">&lt;algorithm&gt;</a></code></div>
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<div>&#35843;&#29992;&#31614;&#21517;</div>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span><span class="sy1">&lt;</span> <span class="kw1">class</span> T, <span class="kw1">class</span> Proj <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>,<br /></span>
<p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; std<span class="sy4">::</span><span class="me2">indirect_strict_weak_order</span><span class="sy1">&lt;</span>std<span class="sy4">::</span><span class="me2">projected</span><span class="sy1">&lt;</span><span class="kw4">const</span> T<span class="sy2">*</span>, Proj<span class="sy1">&gt;&gt;</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span> <span class="sy1">&gt;</span><br /></p>
<span class="kw4">constexpr</span> <span class="kw4">const</span> T<span class="sy3">&amp;</span> clamp<span class="br0">(</span> <span class="kw4">const</span> T<span class="sy3">&amp;</span> v, <span class="kw4">const</span> T<span class="sy3">&amp;</span> lo, <span class="kw4">const</span> T<span class="sy3">&amp;</span> hi, Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj proj <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span> <span class="br0">)</span><span class="sy4">;</span></div>
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<td class="t-dcl-nopad"></td>
<td><span class="t-mark-rev t-since-cxx20">(C++20 &#36215;)</span></td>
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<p>&#33509; <code>v</code> &#27604;&#36739;&#23567;&#20110; <code>lo</code> &#21017;&#36820;&#22238; <code>lo</code> &#65307;&#21542;&#21017;&#33509; <code>hi</code> &#27604;&#36739;&#23567;&#20110; <code>v</code> &#21017;&#36820;&#22238; <code>hi</code> &#65307;&#21542;&#21017;&#36820;&#22238; <code>v</code> &#12290;</p>
<p><br />
&#33509; <code>lo</code> &#30340;&#34987;&#25237;&#24433;&#20540;&#22823;&#20110; <code>hi</code> &#21017;&#34892;&#20026;&#26410;&#23450;&#20041;&#12290;</p>
<p>&#27492;&#39029;&#38754;&#19978;&#25551;&#36848;&#30340;&#20223;&#20989;&#25968;&#23454;&#20307;&#26159; <i>niebloid</i> &#65292;&#21363;&#65306;</p>
<ul>
<li>&#35843;&#29992;&#23427;&#20204;&#20013;&#30340;&#20219;&#20309;&#19968;&#32773;&#26102;&#19981;&#21487;&#25351;&#23450;&#26174;&#24335;&#27169;&#26495;&#23454;&#21442;&#12290;</li>
<li>&#23427;&#20204;&#26080;&#19968;&#23545;<a href="cpp-language-adl.html">&#23454;&#21442;&#20381;&#36182;&#26597;&#25214;</a>&#21487;&#35265;&#12290;</li>
<li>&#22312;<a href="cpp-language-unqualified_lookup.html">&#36890;&#24120;&#26080;&#38480;&#23450;&#26597;&#25214;</a>&#23547;&#25214;&#20989;&#25968;&#35843;&#29992;&#36816;&#31639;&#31526;&#24038;&#20391;&#30340;&#21517;&#31216;&#25214;&#21040;&#23427;&#20204;&#20043;&#19968;&#26102;&#65292;&#23427;&#31105;&#27490;<a href="cpp-language-adl.html">&#23454;&#21442;&#20381;&#36182;&#26597;&#25214;</a>&#12290;</li>
</ul>
<p>&#23454;&#38469;&#19978;&#65292;&#23427;&#20204;&#33021;&#20197;&#20989;&#25968;&#23545;&#35937;&#65292;&#25110;&#20197;&#26576;&#20123;&#29305;&#27530;&#32534;&#35793;&#22120;&#25193;&#23637;&#23454;&#29616;&#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
<table class="t-par-begin">
<tr class="t-par">
<td>v</td>
<td>-</td>
<td>&#24453;&#22841;&#30340;&#20540;</td>
</tr>
<tr class="t-par">
<td>lo, hi</td>
<td>-</td>
<td>&#29992;&#20197;&#22841; <code>v</code> &#30340;&#36793;&#30028;</td>
</tr>
<tr class="t-par">
<td>comp</td>
<td>-</td>
<td>&#24212;&#29992;&#21040;&#25237;&#24433;&#21518;&#20803;&#32032;&#30340;&#27604;&#36739;</td>
</tr>
<tr class="t-par">
<td>proj</td>
<td>-</td>
<td>&#24212;&#29992;&#21040; <code>v</code> &#12289; <code>lo</code> &#21450; <code>hi</code> &#30340;&#25237;&#24433;</td>
</tr>
</table>
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#33509; <code>v</code> &#30340;&#34987;&#25237;&#24433;&#20540;&#23567;&#20110; <code>lo</code> &#30340;&#34987;&#25237;&#24433;&#20540;&#21017;&#20026;&#21040; <code>lo</code> &#30340;&#24341;&#29992;&#65292;&#33509; <code>hi</code> &#30340;&#34987;&#25237;&#24433;&#20540;&#23567;&#20110; <code>v</code> &#30340;&#34987;&#25237;&#24433;&#20540;&#21017;&#20026; <code>hi</code> &#21040;&#30340;&#24341;&#29992;&#65292;&#21542;&#21017;&#20026;&#21040; <code>v</code> &#30340;&#24341;&#29992;&#12290;</p>
<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">&#22797;&#26434;&#24230;</span></h3>
<p>&#33267;&#22810;&#24212;&#29992;&#20108;&#27425;&#27604;&#36739;&#21644;&#19977;&#27425;&#25237;&#24433;&#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.AF.E8.83.BD.E7.9A.84.E5.AE.9E.E7.8E.B0">&#21487;&#33021;&#30340;&#23454;&#29616;</span></h3>
<table class="eq-fun-cpp-table">
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<td>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="kw1">struct</span> clamp_fn <span class="br0">{</span>
<span class="kw1">template</span><span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> Proj <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">identity</span>,
std<span class="sy4">::</span><span class="me2">indirect_strict_weak_order</span><span class="sy1">&lt;</span>std<span class="sy4">::</span><span class="me2">projected</span><span class="sy1">&lt;</span><span class="kw4">const</span> T<span class="sy2">*</span>, Proj<span class="sy1">&gt;&gt;</span> Comp <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">less</span><span class="sy1">&gt;</span>
<span class="kw4">constexpr</span> <span class="kw4">const</span> T<span class="sy3">&amp;</span> operator<span class="br0">(</span><span class="br0">)</span><span class="br0">(</span><span class="kw4">const</span> T<span class="sy3">&amp;</span> v, <span class="kw4">const</span> T<span class="sy3">&amp;</span> lo, <span class="kw4">const</span> T<span class="sy3">&amp;</span> hi,
Comp comp <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span>, Proj proj <span class="sy1">=</span> <span class="br0">{</span><span class="br0">}</span><span class="br0">)</span> <span class="kw4">const</span>
<span class="br0">{</span>
<span class="kw4">auto</span><span class="sy3">&amp;&amp;</span> pv <span class="sy1">=</span> <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj, v<span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">return</span> <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>comp, <a href="cpp-utility-forward.html"><span class="kw1117">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>decltype<span class="br0">(</span>pv<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">(</span>pv<span class="br0">)</span>, <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj, lo<span class="br0">)</span><span class="br0">)</span> <span class="sy4">?</span> lo
<span class="sy4">:</span> <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>comp, <a href="cpp-utility-functional-invoke.html"><span class="kw1058">std::<span class="me2">invoke</span></span></a><span class="br0">(</span>proj, hi<span class="br0">)</span>, <a href="cpp-utility-forward.html"><span class="kw1117">std::<span class="me2">forward</span></span></a><span class="sy1">&lt;</span>decltype<span class="br0">(</span>pv<span class="br0">)</span><span class="sy1">&gt;</span><span class="br0">(</span>pv<span class="br0">)</span><span class="br0">)</span> <span class="sy4">?</span> hi <span class="sy4">:</span> v<span class="sy4">;</span>
<span class="br0">}</span>
<span class="br0">}</span><span class="sy4">;</span>
<span class="kw1">inline</span> <span class="kw4">constexpr</span> clamp_fn clamp<span class="sy4">;</span></pre></div>
</div>
</td>
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<h3><span class="mw-headline" id=".E6.B3.A8.E8.A7.A3">&#27880;&#35299;</span></h3>
<div class="t-template-editlink" style=""></div>
&#33509;&#21442;&#25968;&#20043;&#19968;&#26159;&#20020;&#26102;&#37327;&#65292;&#32780;&#35813;&#21442;&#25968;&#34987;&#36820;&#22238;&#65292;&#21017;&#20197;&#24341;&#29992;&#25429;&#33719; <code>std::ranges::clamp</code> &#30340;&#32467;&#26524;&#20250;&#20135;&#29983;&#19968;&#20010;&#24748;&#22402;&#24341;&#29992;&#65306;
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="kw4">int</span> n <span class="sy1">=</span> <span class="nu0">1</span><span class="sy4">;</span>
<span class="kw4">const</span> <span class="kw4">int</span><span class="sy3">&amp;</span> r <span class="sy1">=</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">clamp</span><span class="br0">(</span>n<span class="sy2">-</span><span class="nu0">1</span>, n<span class="sy2">+</span><span class="nu0">1</span><span class="br0">)</span><span class="sy4">;</span>
<span class="co1">// r &#24748;&#22402;</span></pre></div>
</div>
<p>&#33509; <code>v</code> &#19982;&#20219;&#19968;&#36793;&#30028;&#27604;&#36739;&#31561;&#20215;&#65292;&#21017;&#36820;&#22238;&#21040; <code>v</code> &#32780;&#38750;&#21040;&#36793;&#30028;&#30340;&#24341;&#29992;&#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</span></h3>
<div class="t-example">
<div class="t-example-live-link"></div>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="cpp source-cpp">
<pre class="de1"><span class="co2">#include &lt;algorithm&gt;</span>
<span class="co2">#include &lt;cstdint&gt;</span>
<span class="co2">#include &lt;iostream&gt;</span>
<span class="co2">#include &lt;iomanip&gt;</span>
<span class="co2">#include &lt;string&gt;</span>
<span class="kw1">using</span> <span class="kw1">namespace</span> std<span class="sy4">::</span><span class="me2">literals</span><span class="sy4">;</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; raw clamped to int8_t clamped to uint8_t<span class="es1">\n</span>&quot;</span><span class="sy4">;</span>
<span class="kw1">for</span><span class="br0">(</span><span class="kw4">int</span> <span class="kw4">const</span> v<span class="sy4">:</span> <span class="br0">{</span><span class="sy2">-</span><span class="nu0">129</span>, <span class="sy2">-</span><span class="nu0">128</span>, <span class="sy2">-</span><span class="nu0">1</span>, <span class="nu0">0</span>, <span class="nu0">42</span>, <span class="nu0">127</span>, <span class="nu0">128</span>, <span class="nu0">255</span>, <span class="nu0">256</span><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> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu8">04</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> v
<span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu0">20</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">clamp</span><span class="br0">(</span>v, <a href="cpp-types-integer.html"><span class="kw134">INT8_MIN</span></a>, <a href="cpp-types-integer.html"><span class="kw148">INT8_MAX</span></a><span class="br0">)</span>
<span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu0">21</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">clamp</span><span class="br0">(</span>v, <span class="nu0">0</span>, <a href="cpp-types-integer.html"><span class="kw162">UINT8_MAX</span></a><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</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">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="co1">// &#25237;&#24433;&#20989;&#25968;</span>
<span class="kw4">const</span> <span class="kw4">auto</span> stoi <span class="sy1">=</span> <span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> s<span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> <a href="cpp-string-basic_string-stol.html"><span class="kw1257">std::<span class="me2">stoi</span></span></a><span class="br0">(</span>s<span class="br0">)</span><span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
<span class="co1">// &#21516;&#19978;&#65292;&#20294;&#29992;&#23383;&#31526;&#20018;</span>
<span class="kw1">for</span><span class="br0">(</span><a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> <span class="kw4">const</span> v<span class="sy4">:</span> <span class="br0">{</span><span class="st0">&quot;-129&quot;</span>, <span class="st0">&quot;-128&quot;</span>, <span class="st0">&quot;-1&quot;</span>, <span class="st0">&quot;0&quot;</span>, <span class="st0">&quot;42&quot;</span>, <span class="st0">&quot;127&quot;</span>, <span class="st0">&quot;128&quot;</span>, <span class="st0">&quot;255&quot;</span>, <span class="st0">&quot;256&quot;</span><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> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu8">04</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> v
<span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu0">20</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">clamp</span><span class="br0">(</span>v, <span class="st0">&quot;-128&quot;</span>s, <span class="st0">&quot;127&quot;</span>s, <span class="br0">{</span><span class="br0">}</span>, stoi<span class="br0">)</span>
<span class="sy1">&lt;&lt;</span> <a href="cpp-io-manip-setw.html"><span class="kw1797">std::<span class="me2">setw</span></span></a><span class="br0">(</span><span class="nu0">21</span><span class="br0">)</span> <span class="sy1">&lt;&lt;</span> std<span class="sy4">::</span><span class="me2">ranges</span><span class="sy4">::</span><span class="me2">clamp</span><span class="br0">(</span>v, <span class="st0">&quot;0&quot;</span>s, <span class="st0">&quot;255&quot;</span>s, <span class="br0">{</span><span class="br0">}</span>, stoi<span class="br0">)</span> <span class="sy1">&lt;&lt;</span> <span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="br0">}</span></pre></div>
</div>
<p>&#36755;&#20986;&#65306;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="text source-text">
<pre class="de1">
raw clamped to int8_t clamped to uint8_t
-129 -128 0
-128 -128 0
-1 -1 0
0 0 0
42 42 42
127 127 127
128 127 128
255 127 255
256 127 255
-129 -128 0
-128 -128 0
-1 -1 0
0 0 0
42 42 42
127 127 127
128 127 128
255 127 255
256 127 255</pre></div>
</div>
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
<table class="t-dsc-begin">
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-algorithm-ranges-min.html"><span class="t-lines"><span>ranges::min</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
</div>
</td>
<td>&#36820;&#22238;&#32473;&#23450;&#20540;&#30340;&#36739;&#23567;&#32773;<br />
<span class="t-mark">(niebloid)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-algorithm-ranges-max.html"><span class="t-lines"><span>ranges::max</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
</div>
</td>
<td>&#36820;&#22238;&#32473;&#23450;&#20540;&#30340;&#36739;&#22823;&#32773;<br />
<span class="t-mark">(niebloid)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-utility-in_range.html"><span class="t-lines"><span>in_range</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
</div>
</td>
<td>&#26816;&#26597;&#25972;&#25968;&#20540;&#26159;&#21542;&#22312;&#32473;&#23450;&#25972;&#25968;&#31867;&#22411;&#30340;&#33539;&#22260;&#20869;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="cpp-algorithm-clamp.html"><span class="t-lines"><span>clamp</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx17">(C++17)</span></span></span></div>
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<td>&#22312;&#19968;&#23545;&#36793;&#30028;&#20540;&#38388;&#22841;&#36924;&#19968;&#20010;&#20540;<br />
<span class="t-mark">(&#20989;&#25968;&#27169;&#26495;)</span></td>
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