804 lines
56 KiB
HTML
804 lines
56 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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<head><meta http-equiv="x-ua-compatible" content="ie=edge">
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>范围库 (C++20)</title>
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<link rel="stylesheet" href="ext.css" />
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<link rel="stylesheet" href="site_modules.css" />
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</head>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-cpp_ranges 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">范围库 <span class="t-mark-rev t-since-cxx20">(C++20)</span></h1>
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<div id="bodyContent">
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<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</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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<p>范围库提供处理元素范围的组件，包括各种视图适配器。</p>
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<table class="t-dcl-begin">
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<tbody>
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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><a href="cpp-header-ranges.html"><ranges></a></code></div>
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</td>
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<td></td>
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<td></td>
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</tr>
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<tr class="t-dcl t-since-cxx20">
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<td>
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<div><span class="mw-geshi cpp source-cpp"><span class="kw1">namespace</span> std <span class="br0">{</span><br /></span>
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<p> <span class="kw1">namespace</span> views <span class="sy1">=</span> ranges<span class="sy4">::</span><span class="me2">views</span><span class="sy4">;</span><br /></p>
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<span class="br0">}</span></div>
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</td>
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<td class="t-dcl-nopad"></td>
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<td><span class="t-mark-rev t-since-cxx20">(C++20 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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<p>提供命名空间别名 <code>std::views</code> ，作为 <code>std::ranges::views</code> 的缩写。</p>
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<table class="t-dsc-begin">
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<tr class="t-dsc-header">
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<td colspan="2">
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<div>定义于命名空间 <code>std::ranges</code></div>
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</td>
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</tr>
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<tr>
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<td colspan="2">
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<h5><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E8.AE.BF.E9.97.AE">范围访问</span></h5>
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</td>
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</tr>
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<tr class="t-dsc-header">
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<td colspan="2">
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<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
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</td>
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</tr>
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<tr class="t-dsc-header">
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<td colspan="2">
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<div>定义于头文件 <code><a href="cpp-header-iterator.html"><iterator></a></code></div>
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</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="cpp-ranges-begin.html"><span class="t-lines"><span>ranges::begin</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指向范围起始的迭代器<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-end.html"><span class="t-lines"><span>ranges::end</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指示范围结尾的哨位<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-cbegin.html"><span class="t-lines"><span>ranges::cbegin</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指向只读范围起始的迭代器<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-cend.html"><span class="t-lines"><span>ranges::cend</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指示只读范围结尾的哨位<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-rbegin.html"><span class="t-lines"><span>ranges::rbegin</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指向范围的逆向迭代器<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-rend.html"><span class="t-lines"><span>ranges::rend</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指向范围的逆向尾迭代器<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-crbegin.html"><span class="t-lines"><span>ranges::crbegin</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指向只读范围的逆向迭代器<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-crend.html"><span class="t-lines"><span>ranges::crend</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回指向只读范围的逆向尾迭代器<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-size.html"><span class="t-lines"><span>ranges::size</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回等于范围大小的整数<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-ssize.html"><span class="t-lines"><span>ranges::ssize</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>返回等于范围大小的有符号整数<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-empty.html"><span class="t-lines"><span>ranges::empty</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>检查范围是否为空<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-data.html"><span class="t-lines"><span>ranges::data</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>获得指向连续范围的起始的指针<br />
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<span class="t-mark">(定制点对象)</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="cpp-ranges-cdata.html"><span class="t-lines"><span>ranges::cdata</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>获得指向只读连续范围的起始的指针<br />
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<span class="t-mark">(定制点对象)</span></td>
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</tr>
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<tr>
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<td colspan="2">
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<h5><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E5.8E.9F.E8.AF.AD">范围原语</span></h5>
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</td>
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</tr>
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<tr class="t-dsc-header">
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<td colspan="2">
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<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
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</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="cpp-ranges-iterator_t.html"><span class="t-lines"><span>ranges::iterator_t</span><span>ranges::sentinel_t</span><span>ranges::range_difference_t</span><span>ranges::range_size_t</span><span>ranges::range_value_t</span><span>ranges::range_reference_t</span><span>ranges::range_rvalue_reference_t</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>获得范围的关联类型<br />
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<span class="t-mark">(别名模板)</span></td>
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</tr>
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<tr>
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<td colspan="2">
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<h5><span class="mw-headline" id=".E6.82.AC.E5.9E.82.E8.BF.AD.E4.BB.A3.E5.99.A8.E5.A4.84.E7.90.86">悬垂迭代器处理</span></h5>
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</td>
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</tr>
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<tr class="t-dsc-header">
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<td colspan="2">
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<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
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</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="cpp-ranges-dangling.html"><span class="t-lines"><span>ranges::dangling</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>占位类型，指示不应返回迭代器或子范围，因为它可能悬垂<br />
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<span class="t-mark">(类)</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="cpp-ranges-borrowed_iterator_t.html"><span class="t-lines"><span>ranges::borrowed_iterator_t</span><span>ranges::borrowed_subrange_t</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>获得塑造 <a href="cpp-ranges-borrowed_range.html"><code>borrowed_range</code></a> 的迭代器类型或子范围类型<br />
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<span class="t-mark">(别名模板)</span></td>
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</tr>
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<tr>
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<td colspan="2">
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<h5><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E6.A6.82.E5.BF.B5">范围概念</span></h5>
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</td>
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</tr>
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<tr class="t-dsc-header">
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<td colspan="2">
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<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
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</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="cpp-ranges-range.html"><span class="t-lines"><span>ranges::range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定类型为范围，即它同时提供 <code>begin</code> 迭代器和 <code>end</code> 哨位<br />
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<span class="t-mark">(概念)</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="cpp-ranges-borrowed_range.html"><span class="t-lines"><span>ranges::borrowed_range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定类型为 <a href="cpp-ranges-range.html"><code>range</code></a> 而且能安全返回从该类型表达式获得的迭代器而无悬垂之虞<br />
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<span class="t-mark">(概念)</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="cpp-ranges-sized_range.html"><span class="t-lines"><span>ranges::sized_range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定范围可在常数时间内知晓其大小<br />
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<span class="t-mark">(概念)</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="cpp-ranges-view.html"><span class="t-lines"><span>ranges::view</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定范围为视图，即它拥有常数时间的复制/移动/赋值<br />
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<span class="t-mark">(概念)</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="cpp-ranges-input_range.html"><span class="t-lines"><span>ranges::input_range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定范围的迭代器类型满足 <a href="cpp-iterator-input_iterator.html"><code>input_iterator</code></a><br />
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<span class="t-mark">(概念)</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="cpp-ranges-output_range.html"><span class="t-lines"><span>ranges::output_range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定范围的迭代器类型满足 <a href="cpp-iterator-output_iterator.html"><code>output_iterator</code></a><br />
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<span class="t-mark">(概念)</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="cpp-ranges-forward_range.html"><span class="t-lines"><span>ranges::forward_range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定范围的迭代器类型满足 <a href="cpp-iterator-forward_iterator.html"><code>forward_iterator</code></a><br />
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<span class="t-mark">(概念)</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="cpp-ranges-bidirectional_range.html"><span class="t-lines"><span>ranges::bidirectional_range</span></span></a></div>
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<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx20">(C++20)</span></span></span></div>
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</div>
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</td>
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<td>指定范围的迭代器类型满足 <a href="cpp-iterator-bidirectional_iterator.html"><code>bidirectional_iterator</code></a><br />
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<span class="t-mark">(概念)</span></td>
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</tr>
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<tr class="t-dsc">
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|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-random_access_range.html"><span class="t-lines"><span>ranges::random_access_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>指定范围的迭代器类型满足 <a href="cpp-iterator-random_access_iterator.html"><code>random_access_iterator</code></a><br />
|
|
<span class="t-mark">(概念)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-contiguous_range.html"><span class="t-lines"><span>ranges::contiguous_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>指定范围的迭代器类型满足 <a href="cpp-iterator-contiguous_iterator.html"><code>contiguous_iterator</code></a><br />
|
|
<span class="t-mark">(概念)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-common_range.html"><span class="t-lines"><span>ranges::common_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>指定范围拥有相同的迭代器和哨位类型<br />
|
|
<span class="t-mark">(概念)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-viewable_range.html"><span class="t-lines"><span>ranges::viewable_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>指定针对 <a href="cpp-ranges-range.html"><code>range</code></a> 的要求，令其可安全转换为 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(概念)</span></td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="2">
|
|
<h5><span class="mw-headline" id=".E8.A7.86.E5.9B.BE">视图</span></h5>
|
|
</td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td colspan="2">
|
|
<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
|
|
</td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-view_interface.html"><span class="t-lines"><span>ranges::view_interface</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>用于定义 <a href="cpp-ranges-view.html"><code>view</code></a> 的辅助类模板，使用奇异递归模板模式<br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-subrange.html"><span class="t-lines"><span>ranges::subrange</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>将迭代器/哨位对结合为一个 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E5.B7.A5.E5.8E.82">范围工厂</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc-header">
|
|
<td colspan="2">
|
|
<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
|
|
</td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td colspan="2">
|
|
<div>定义于命名空间 <code>std::ranges</code></div>
|
|
</td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-empty_view.html"><span class="t-lines"><span>ranges::empty_view</span><span>views::empty</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>无元素的空 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(变量模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-single_view.html"><span class="t-lines"><span>ranges::single_view</span><span>views::single</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>含有具有指定值的单个元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(定制点对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-iota_view.html"><span class="t-lines"><span>ranges::iota_view</span><span>views::iota</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>由通过重复对某个初值自增所生成的序列组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(定制点对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-basic_istream_view.html"><span class="t-lines"><span>ranges::basic_istream_view</span><span>views::istream</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>由在关联的输入流上相继应用 <code>operator>></code> 获得的元素组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(定制点对象)</span></td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E9.80.82.E9.85.8D.E5.99.A8">范围适配器</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc-header">
|
|
<td colspan="2">
|
|
<div>定义于头文件 <code><a href="cpp-header-ranges.html"><ranges></a></code></div>
|
|
</td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td colspan="2">
|
|
<div>定义于命名空间 <code>std::ranges</code></div>
|
|
</td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-all_view.html"><span class="t-lines"><span>views::all_t</span><span>views::all</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>包含 <a href="cpp-ranges-range.html"><code>range</code></a> 的所有元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(别名模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-ref_view.html"><span class="t-lines"><span>ranges::ref_view</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>某个其他 <a href="cpp-ranges-range.html"><code>range</code></a> 的元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-owning_view.html"><span class="t-lines"><span>ranges::owning_view</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>拥有某 <a href="cpp-ranges-range.html"><code>range</code></a> 的独占所有权的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-filter_view.html"><span class="t-lines"><span>ranges::filter_view</span><span>views::filter</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>由 <a href="cpp-ranges-range.html"><code>range</code></a> 中满足某个谓词的元素构成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-transform_view.html"><span class="t-lines"><span>ranges::transform_view</span><span>views::transform</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>对序列的每个元素应用某个变换函数的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-take_view.html"><span class="t-lines"><span>ranges::take_view</span><span>views::take</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>由另一 <a href="cpp-ranges-view.html"><code>view</code></a> 的前 N 个元素组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-take_while_view.html"><span class="t-lines"><span>ranges::take_while_view</span><span>views::take_while</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>由另一 <a href="cpp-ranges-view.html"><code>view</code></a> 的到首个谓词返回 <code>false</code> 为止的起始元素组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-drop_view.html"><span class="t-lines"><span>ranges::drop_view</span><span>views::drop</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>由另一 <a href="cpp-ranges-view.html"><code>view</code></a> 跳过首 N 个元素组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-drop_while_view.html"><span class="t-lines"><span>ranges::drop_while_view</span><span>views::drop_while</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>由另一 <a href="cpp-ranges-view.html"><code>view</code></a> 跳过元素的起始序列，直至首个谓词返回 <code>false</code> 的元素组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-join_view.html"><span class="t-lines"><span>ranges::join_view</span><span>views::join</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>由拉平 <a href="cpp-ranges-range.html"><code>range</code></a> 的 <a href="cpp-ranges-view.html"><code>view</code></a> 所获得的序列构成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/ranges/split_view&action=edit&redlink=1" class="new" title="cpp/ranges/split view（页面不存在）"><span class="t-lines"><span>ranges::split_view</span><span>views::split</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>用某个分隔符切割另一 <a href="cpp-ranges-view.html"><code>view</code></a> 所获得的子范围的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/ranges/lazy_split_view&action=edit&redlink=1" class="new" title="cpp/ranges/lazy split view（页面不存在）"><span class="t-lines"><span>ranges::lazy_split_view</span><span>views::lazy_split</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>用某个分隔符切割另一 <a href="cpp-ranges-view.html"><code>view</code></a> 所获得的子范围的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-view_counted.html"><span class="t-lines"><span>views::counted</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>从迭代器和计数创建子范围<br />
|
|
<span class="t-mark">(定制点对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-common_view.html"><span class="t-lines"><span>ranges::common_view</span><span>views::common</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>转换 <a href="cpp-ranges-view.html"><code>view</code></a> 为 <a href="cpp-ranges-common_range.html"><code>common_range</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-reverse_view.html"><span class="t-lines"><span>ranges::reverse_view</span><span>views::reverse</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>以逆序迭代另一双向视图上的元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-elements_view.html"><span class="t-lines"><span>ranges::elements_view</span><span>views::elements</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>选取元组式值组成的 <a href="cpp-ranges-view.html"><code>view</code></a> 和数值 N ，产生每个 tuple 的第 N 个元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-keys_view.html"><span class="t-lines"><span>ranges::keys_view</span><span>views::keys</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>选取 pair 式值组成的 <a href="cpp-ranges-view.html"><code>view</code></a> 并产生每个 pair 的第一元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="cpp-ranges-values_view.html"><span class="t-lines"><span>ranges::values_view</span><span>views::values</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>选取 pair 式值组成的 <a href="cpp-ranges-view.html"><code>view</code></a> 并产生每个 pair 的第二元素的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/ranges/zip_view&action=edit&redlink=1" class="new" title="cpp/ranges/zip view（页面不存在）"><span class="t-lines"><span>ranges::zip_view</span><span>views::zip</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>到被适配视图的对应元素的引用元组组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(定制点对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/ranges/zip_transform_view&action=edit&redlink=1" class="new" title="cpp/ranges/zip transform view（页面不存在）"><span class="t-lines"><span>ranges::zip_transform_view</span><span>views::zip_transform</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>由应用变换函数到被适配视图的对应元素的结果的元组组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(定制点对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/ranges/adjacent_view&action=edit&redlink=1" class="new" title="cpp/ranges/adjacent view（页面不存在）"><span class="t-lines"><span>ranges::adjacent_view</span><span>views::adjacent</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>由到被适配视图的相邻元素的引用的元组组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="https://zh.cppreference.com/mwiki/index.php?title=cpp/ranges/adjacent_transform_view&action=edit&redlink=1" class="new" title="cpp/ranges/adjacent transform view（页面不存在）"><span class="t-lines"><span>ranges::adjacent_transform_view</span><span>views::adjacent_transform</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-cxx23">(C++23)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>由应用变换函数到被适配视图的相邻元素的结果的元组组成的 <a href="cpp-ranges-view.html"><code>view</code></a><br />
|
|
<span class="t-mark">(类模板)</span> <span class="t-mark">(范围适配器对象)</span></td>
|
|
</tr>
|
|
</table>
|
|
<p>某些范围适配器用<a href="cpp-ranges-copyable_wrapper.html">可复制包装</a>包装其元素或函数对象。</p>
|
|
<h4><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E9.80.82.E9.85.8D.E5.99.A8.E5.AF.B9.E8.B1.A1">范围适配器对象</span></h4>
|
|
<p><i>范围适配器对象</i>是接收 <a href="cpp-ranges-viewable_range.html"><code>viewable_range</code></a> 作为其首参数并返回 <a href="cpp-ranges-view.html"><code>view</code></a> 的定制点对象。一些范围适配器对象是一元的，即它们接收一个 <a href="cpp-ranges-viewable_range.html"><code>viewable_range</code></a> 作为其仅有的参数。其他范围适配器对象接收一个 <a href="cpp-ranges-viewable_range.html"><code>viewable_range</code></a> 和其他尾随参数。</p>
|
|
<p>若范围适配器接收多于一个参数，则它亦支持部分应用：令</p>
|
|
<ul>
|
|
<li><code>a</code> 为范围适配器对象，而</li>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp">args...</span></span> 为参数（通常适合作为尾随参数），</li>
|
|
</ul>
|
|
<p>则表达式 <span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="br0">(</span>args...<span class="br0">)</span></span></span> 拥有下列属性：</p>
|
|
<ul>
|
|
<li>它合法当且仅当对每个 <span class="t-c"><span class="mw-geshi cpp source-cpp">args...</span></span> 中的 <span class="t-c"><span class="mw-geshi cpp source-cpp">e</span></span> ，设 <code>E</code> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp">decltype<span class="br0">(</span><span class="br0">(</span>e<span class="br0">)</span><span class="br0">)</span></span></span> ， <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-is_constructible.html"><span class="kw521">std::<span class="me2">is_constructible_v</span></span></a><span class="sy1"><</span><a href="cpp-types-decay.html"><span class="kw629">std::<span class="me2">decay_t</span></span></a><span class="sy1"><</span>E<span class="sy1">></span>, E<span class="sy1">></span></span></span> 为 <span class="t-c"><span class="mw-geshi cpp source-cpp"><span class="kw2">true</span></span></span> ，</li>
|
|
<li>当调用合法时，其结果对象对每个 <span class="t-c"><span class="mw-geshi cpp source-cpp">e</span></span> 中的 <span class="t-c"><span class="mw-geshi cpp source-cpp">args...</span></span> 存储以 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-forward.html"><span class="kw1117">std::<span class="me2">forward</span></span></a><span class="sy1"><</span>E<span class="sy1">></span><span class="br0">(</span>e<span class="br0">)</span></span></span> 直接非列表初始化的 <span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-types-decay.html"><span class="kw629">std::<span class="me2">decay_t</span></span></a><span class="sy1"><</span>E<span class="sy1">></span></span></span> 类型子对象，而且</li>
|
|
<li>结果对象是范围适配器闭包对象（见后述）。</li>
|
|
</ul>
|
|
<p>类似其他定制点对象，令</p>
|
|
<ul>
|
|
<li><code>a</code> 为任何范围适配器类型的 cv 无限定版本的对象，</li>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp">args...</span></span> 任何满足 <code>a</code> 的 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="br0">(</span><span class="br0">)</span></span></span> 的约束参数组，</li>
|
|
</ul>
|
|
<p>对</p>
|
|
<ul>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp">a<span class="br0">(</span>args...<span class="br0">)</span></span></span>、</li>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp"><a href="cpp-utility-as_const.html"><span class="kw1121">std::<span class="me2">as_const</span></span></a><span class="br0">(</span>a<span class="br0">)</span><span class="br0">(</span>args...<span class="br0">)</span></span></span>、</li>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span>a<span class="br0">)</span><span class="br0">(</span>args...<span class="br0">)</span></span></span> 及</li>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp">std<span class="sy4">::</span><span class="me2">move</span><span class="br0">(</span><a href="cpp-utility-as_const.html"><span class="kw1121">std::<span class="me2">as_const</span></span></a><span class="br0">(</span>a<span class="br0">)</span><span class="br0">)</span><span class="br0">(</span>args...<span class="br0">)</span></span></span></li>
|
|
</ul>
|
|
<p>的调用全部等价。</p>
|
|
<p>每个这些表达式的结果对象是一个 <a href="cpp-ranges-view.html"><code>view</code></a> 对象或范围适配器闭包对象。</p>
|
|
<p>注：范围适配器类型的 volatile 限定或 const-volatile 限定版本不支持 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="br0">(</span><span class="br0">)</span></span></span> 。数组和函数在绑定时转换成指针。</p>
|
|
<h4><span class="mw-headline" id=".E8.8C.83.E5.9B.B4.E9.80.82.E9.85.8D.E5.99.A8.E9.97.AD.E5.8C.85.E5.AF.B9.E8.B1.A1">范围适配器闭包对象</span></h4>
|
|
<p><i>范围适配器闭包对象</i>是类型同下列对象之一（忽略 cv 限定）的对象：</p>
|
|
<ul>
|
|
<li>一元范围适配器对象、</li>
|
|
<li>范围适配器对象绑定尾随参数的结果，及</li>
|
|
<li><span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy3">|</span></span></span> 连接两个范围适配器闭包对象的结果。</li>
|
|
</ul>
|
|
<p>范围适配器对象接收一个 <a href="cpp-ranges-viewable_range.html"><code>viewable_range</code></a> 作为其仅有的参数并返回 <a href="cpp-ranges-view.html"><code>view</code></a> 。它们可通过管道运算符调用：若 <span class="t-c"><span class="mw-geshi cpp source-cpp">C</span></span> 是范围适配器闭包对象且 <span class="t-c"><span class="mw-geshi cpp source-cpp">R</span></span> 为 <a href="cpp-ranges-viewable_range.html"><code>viewable_range</code></a> ，则下列两个表达式等价（均为良构或非良构）：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="cpp source-cpp">
|
|
<pre class="de1">C<span class="br0">(</span>R<span class="br0">)</span>
|
|
R <span class="sy3">|</span> C</pre></div>
|
|
</div>
|
|
<p>此调用将绑定的参数（若存在）转发给关联的范围适配器对象。绑定的参数（若存在）被当作与 <span class="t-c"><span class="mw-geshi cpp source-cpp">C</span></span> 等同地为左值或右值以及具有 cv 限定。</p>
|
|
<p>两个范围适配器闭包对象能由 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="sy3">|</span></span></span> 连接以产生另一个范围适配器闭包对象：若 <span class="t-c"><span class="mw-geshi cpp source-cpp">C</span></span> 与 <span class="t-c"><span class="mw-geshi cpp source-cpp">D</span></span> 为范围适配器闭包对象，则 <span class="t-c"><span class="mw-geshi cpp source-cpp">C <span class="sy3">|</span> D</span></span> 亦为范围适配器闭包对象，若它合法。</p>
|
|
<p><span class="t-c"><span class="mw-geshi cpp source-cpp">C <span class="sy3">|</span> D</span></span> 的绑定参数确定如下：</p>
|
|
<ul>
|
|
<li>对两个操作数中的每个作为绑定参数的子对象，结果对象中有一个同类型子对象（舍弃 cv 限定），</li>
|
|
<li>这种绑定的参数以含有它的操作数中的源子对象直接非列表初始化，其中源被当作与操作数等同地为左值或右值以及具有 cv 限定，而且</li>
|
|
<li>结果合法当且仅当所有绑定参数的初始化为合法。</li>
|
|
</ul>
|
|
<p>结果的 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="br0">(</span><span class="br0">)</span></span></span> 的效果与合法性确定如下：给定 <a href="cpp-ranges-viewable_range.html"><code>viewable_range</code></a> <span class="t-c"><span class="mw-geshi cpp source-cpp">R</span></span> ，这两个表达式等价（均为合法或非合法）：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="cpp source-cpp">
|
|
<pre class="de1">R <span class="sy3">|</span> C <span class="sy3">|</span> D <span class="co1">// (R | C) | D</span>
|
|
R <span class="sy3">|</span> <span class="br0">(</span>C <span class="sy3">|</span> D<span class="br0">)</span></pre></div>
|
|
</div>
|
|
<p>注意：范围适配器闭包类型的 volatile 限定或 const-volatile 限定版本不支持 <span class="t-c"><span class="mw-geshi cpp source-cpp">operator<span class="br0">(</span><span class="br0">)</span></span></span> 。</p>
|
|
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</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 <ranges></span>
|
|
<span class="co2">#include <iostream></span>
|
|
|
|
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
<span class="kw4">auto</span> <span class="kw4">const</span> ints <span class="sy1">=</span> <span class="br0">{</span><span class="nu0">0</span>,<span class="nu0">1</span>,<span class="nu0">2</span>,<span class="nu0">3</span>,<span class="nu0">4</span>,<span class="nu0">5</span><span class="br0">}</span><span class="sy4">;</span>
|
|
<span class="kw4">auto</span> even <span class="sy1">=</span> <span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">int</span> i<span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> <span class="nu0">0</span> <span class="sy1">==</span> i <span class="sy2">%</span> <span class="nu0">2</span><span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
|
|
<span class="kw4">auto</span> square <span class="sy1">=</span> <span class="br0">[</span><span class="br0">]</span><span class="br0">(</span><span class="kw4">int</span> i<span class="br0">)</span> <span class="br0">{</span> <span class="kw1">return</span> i <span class="sy2">*</span> i<span class="sy4">;</span> <span class="br0">}</span><span class="sy4">;</span>
|
|
|
|
<span class="co1">// 组合视图的“管道”语法：</span>
|
|
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">int</span> i <span class="sy4">:</span> ints <span class="sy3">|</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">filter</span><span class="br0">(</span>even<span class="br0">)</span> <span class="sy3">|</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">transform</span><span class="br0">(</span>square<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"><<</span> i <span class="sy1"><<</span> <span class="st0">' '</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"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
|
|
<span class="co1">// 传统的“函数式”组合语法：</span>
|
|
<span class="kw1">for</span> <span class="br0">(</span><span class="kw4">int</span> i <span class="sy4">:</span> std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">transform</span><span class="br0">(</span>std<span class="sy4">::</span><span class="me2">views</span><span class="sy4">::</span><span class="me2">filter</span><span class="br0">(</span>ints, even<span class="br0">)</span>, square<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"><<</span> i <span class="sy1"><<</span> <span class="st0">' '</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>输出：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">0 4 16</pre></div>
|
|
</div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E7.BC.BA.E9.99.B7.E6.8A.A5.E5.91.8A">缺陷报告</span></h3>
|
|
<p>下列更改行为的缺陷报告追溯地应用于以前出版的 C++ 标准。</p>
|
|
<table class="dsctable" style="font-size:0.8em">
|
|
<tr>
|
|
<th>DR</th>
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<th>应用于</th>
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<th>出版时的行为</th>
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<th>正确行为</th>
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</tr>
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<tr>
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<td><a rel="nofollow" class="external text" href="https://cplusplus.github.io/LWG/issue3509">LWG 3509</a></td>
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<td>C++20</td>
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<td>不明确范围适配器对象如何绑定尾随参数</td>
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<td>按值绑定它们</td>
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</tr>
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</table>
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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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