168 lines
12 KiB
HTML
168 lines
12 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
|
|
<head><meta http-equiv="x-ua-compatible" content="ie=edge">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<title>std::basic_string_view<CharT,Traits>::compare</title>
|
|
<link rel="stylesheet" href="ext.css" />
|
|
<link rel="stylesheet" href="site_modules.css" />
|
|
</head>
|
|
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_string_basic_string_view_compare skin-cppreference2 action-view cpp-navbar">
|
|
<div id="cpp-content-base">
|
|
<div id="content"><a id="top"></a>
|
|
<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::basic_string_view<CharT,Traits>::</span>compare</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-string.html">string</a>‎ | <a href="cpp-string-basic_string_view.html">basic string view</a></span></div>
|
|
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
|
|
<table class="t-dcl-begin">
|
|
<tbody>
|
|
<tr class="t-dcl t-since-cxx17">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">int</span> compare<span class="br0">(</span>basic_string_view v<span class="br0">)</span> <span class="kw4">const</span> <span class="kw1">noexcept</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(1)</td>
|
|
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx17">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">int</span> compare<span class="br0">(</span>size_type pos1, size_type count1,<br />
|
|
basic_string_view v<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(2)</td>
|
|
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx17">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">int</span> compare<span class="br0">(</span>size_type pos1, size_type count1, basic_string_view v,<br />
|
|
size_type pos2, size_type count2<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(3)</td>
|
|
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx17">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">int</span> compare<span class="br0">(</span><span class="kw4">const</span> CharT<span class="sy2">*</span> s<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(4)</td>
|
|
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx17">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">int</span> compare<span class="br0">(</span>size_type pos1, size_type count1,<br />
|
|
<span class="kw4">const</span> CharT<span class="sy2">*</span> s<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(5)</td>
|
|
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-cxx17">
|
|
<td>
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">constexpr</span> <span class="kw4">int</span> compare<span class="br0">(</span>size_type pos1, size_type count1,<br />
|
|
<span class="kw4">const</span> CharT<span class="sy2">*</span> s, size_type count2<span class="br0">)</span> <span class="kw4">const</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(6)</td>
|
|
<td><span class="t-mark-rev t-since-cxx17">(C++17 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>比较二个字符序列。</p>
|
|
<div class="t-li1"><span class="t-li">1)</span> 要比较的序列长度 <code>rlen</code> 是 <span class="t-c"><span class="mw-geshi cpp source-cpp">size<span class="br0">(</span><span class="br0">)</span></span></span> 与 <span class="t-c"><span class="mw-geshi cpp source-cpp">v.<span class="me1">size</span><span class="br0">(</span><span class="br0">)</span></span></span> 的较小者。该函数通过调用 <span class="t-c"><span class="mw-geshi cpp source-cpp">traits<span class="sy4">::</span><span class="me2">compare</span><span class="br0">(</span>data<span class="br0">(</span><span class="br0">)</span>, v.<span class="me1">data</span><span class="br0">(</span><span class="br0">)</span>, rlen<span class="br0">)</span></span></span> 比较二个视图，并根据下表返回一个值：</div>
|
|
<table class="wikitable" style="text-align:center;">
|
|
<tr>
|
|
<th colspan="2">条件</th>
|
|
<th>结果</th>
|
|
<th>返回值</th>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="2" style="text-align:left;"><code>Traits::compare(data(), v.data(), <span class="t-spar">rlen</span>) < 0</code></td>
|
|
<td><code>*this</code> <i>小于</i> <code>v</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1"><</span><span class="nu0">0</span></span></span></td>
|
|
</tr>
|
|
<tr>
|
|
<td rowspan="3"><code>Traits::compare(data(), v.data(), <span class="t-spar">rlen</span>) == 0</code></td>
|
|
<td><code>size() < v.size()</code></td>
|
|
<td><code>*this</code><i>小于</i> <code>v</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1"><</span><span class="nu0">0</span></span></span></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>size() == v.size()</code></td>
|
|
<td><code>*this</code> <i>等于</i> <code>v</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp">​<span class="nu0">0</span>​</span></span></td>
|
|
</tr>
|
|
<tr>
|
|
<td><code>size() > v.size()</code></td>
|
|
<td><code>*this</code> <i>大于</i> <code>v</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">></span><span class="nu0">0</span></span></span></td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="2" style="text-align:left;"><code>Traits::compare(data(), v.data(), <span class="t-spar">rlen</span>) > 0</code></td>
|
|
<td><code>*this</code> <i>大于</i> <code>v</code></td>
|
|
<td><span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="sy1">></span><span class="nu0">0</span></span></span></td>
|
|
</tr>
|
|
</table>
|
|
<div class="t-li1"><span class="t-li">2)</span> 等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp">substr<span class="br0">(</span>pos1, count1<span class="br0">)</span>.<span class="me1">compare</span><span class="br0">(</span>v<span class="br0">)</span></span></span> 。</div>
|
|
<div class="t-li1"><span class="t-li">3)</span> 等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp">substr<span class="br0">(</span>pos1, count1<span class="br0">)</span>.<span class="me1">compare</span><span class="br0">(</span>v.<span class="me1">substr</span><span class="br0">(</span>pos2, count2<span class="br0">)</span><span class="br0">)</span></span></span> 。</div>
|
|
<div class="t-li1"><span class="t-li">4)</span> 等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp">compare<span class="br0">(</span>basic_string_view<span class="br0">(</span>s<span class="br0">)</span><span class="br0">)</span></span></span> 。</div>
|
|
<div class="t-li1"><span class="t-li">5)</span> 等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp">substr<span class="br0">(</span>pos1, count1<span class="br0">)</span>.<span class="me1">compare</span><span class="br0">(</span>basic_string_view<span class="br0">(</span>s<span class="br0">)</span><span class="br0">)</span></span></span> 。</div>
|
|
<div class="t-li1"><span class="t-li">6)</span> 等价于 <span class="t-c"><span class="mw-geshi cpp source-cpp">substr<span class="br0">(</span>pos1, count1<span class="br0">)</span>.<span class="me1">compare</span><span class="br0">(</span>basic_string_view<span class="br0">(</span>s, count2<span class="br0">)</span><span class="br0">)</span></span></span> 。</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
|
|
<table class="t-par-begin">
|
|
<tr class="t-par">
|
|
<td>v</td>
|
|
<td>-</td>
|
|
<td>要比较的视图</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>s</td>
|
|
<td>-</td>
|
|
<td>指向要比较的字符串的指针</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>count1</td>
|
|
<td>-</td>
|
|
<td>此视图的要比较的字符数</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>pos1</td>
|
|
<td>-</td>
|
|
<td>此视图中要比较的首字符位置</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>count2</td>
|
|
<td>-</td>
|
|
<td>给定视图的要比较的字符数</td>
|
|
</tr>
|
|
<tr class="t-par">
|
|
<td>pos2</td>
|
|
<td>-</td>
|
|
<td>给定视图的要比较的首字符位置</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
|
|
<p>若此视图小于另一字符序列则为负值，若二个字符序列相等则为零，若此视图大于另一字符序列则为正值。</p>
|
|
<h3><span class="mw-headline" id=".E5.A4.8D.E6.9D.82.E5.BA.A6">复杂度</span></h3>
|
|
<div class="t-li1"><span class="t-li">1)</span> 与比较的字符数成线性。</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-string-basic_string_view-operator_cmp.html"><span class="t-lines"><span>operator==</span><span>operator!=</span><span>operator<</span><span>operator></span><span>operator<=</span><span>operator>=</span><span>operator<=></span></span></a></div>
|
|
<div><span class="t-lines"><span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span><span><span class="t-mark-rev t-until-cxx20">(C++20 中移除)</span></span><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>以字典序比较两个字符串视图<br />
|
|
<span class="t-mark">(函数模板)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|