使用基于范围的 for 循环迭代范围

<div class="output_wrapper" id="output_wrapper_id" style="font-size: 17px; color: rgb(62, 62, 62); line-height: 1.6; word-spacing: 1px; letter-spacing: 1px; font-family: 'Helvetica Neue', Helvetica, 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;"><blockquote style="line-height: inherit; display: block; padding: 15px 15px 15px 1rem; font-size: 0.9em; margin: 1em 0px; color: rgb(129, 145, 152); border-left: 6px solid rgb(220, 230, 240); background: rgb(242, 247, 251); overflow: auto; overflow-wrap: normal; word-break: normal;"> 特别声明： 本文翻译自 Modern C++ Programming Cookbook 一书中的“Learning Modern Core Language Features”章节中的“Using range-based for loops to iterate on a range”小节。 翻译此文纯粹做为学习之用，版权归原做者及出版社全部。 </blockquote> 许多编程语言支持 for 循环的称之为 for each 的变体，即针对集合中的元素重复一组语句。在 C++11 以前 C++没有相应的核心语言支持。最接近的特性是来自标准库中的被称为 std::for_each 的通用算法，它在范围的全部元素上应用一个函数。C++11 带来了对 for each 的语言级支持，实际称之为基于范围 for 循环。新的 C++17 标准对原始语言特性提供了一些改进。 <h3 id="hgettingready" style="color: inherit; line-height: inherit; padding: 0px; margin: 1.5em 0px; font-weight: bold; font-size: 1.3em; border-bottom: 2px solid rgb(0, 172, 193);"><span style="font-size: inherit; line-height: inherit; margin: 0px; display: inline-block; font-weight: normal; background: rgb(0, 172, 193); color: rgb(255, 255, 255); padding: 3px 10px 0px; border-top-right-radius: 3px; border-top-left-radius: 4px; margin-right: 2px;">Getting ready</h3> 在 C++11 中，基于范围 for 循环的通用语法以下： <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">1for (range_declaration : range_expression) loop_statement </code></pre> 为了举例说明基于范围的 for 循环的不一样用法，咱们将使用下面这些函数返回元素序列： <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 1std::vector<int> getRates() <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 2{ <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 3    return std::vector<int>{1, 1, 2, 3, 5, 8, 13}; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 4} <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 5 <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 6std::multimap<int, bool> getRates2() <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 7{ <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 8    return std::multimap<int, bool>{ <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 9        {1, true}, <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">10        {1, true}, <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">11        {2, false}, <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">12        {3, true}, <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">13        {5, true}, <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">14        {8, false}, <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">15        {13, true} <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">16      }; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">17} </code></pre> <h3 id="hhowtodoit" style="color: inherit; line-height: inherit; padding: 0px; margin: 1.5em 0px; font-weight: bold; font-size: 1.3em; border-bottom: 2px solid rgb(0, 172, 193);"><span style="font-size: inherit; line-height: inherit; margin: 0px; display: inline-block; font-weight: normal; background: rgb(0, 172, 193); color: rgb(255, 255, 255); padding: 3px 10px 0px; border-top-right-radius: 3px; border-top-left-radius: 4px; margin-right: 2px;">How to do it…</h3> 基于范围的 for 循环能够经过不一样的方式使用： <ul style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; padding-left: 32px; list-style-type: disc;"> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">为序列元素提供一个特定类型：</li> </ul> <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">1auto rates = getRates(); <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">2for (int rate : rates) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">3    std::cout << rate << std::endl; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">4 <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">5for (int &rate : rates) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">6    rate *= 2; </code></pre> <ul style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; padding-left: 32px; list-style-type: disc;"> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">不指定类型并由编译器进行推导：</li> </ul> <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">1for (auto &&rate : getRates()) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">2    std::cout << rate << std::endl; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">3 <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">4for (auto &rate : rates) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">5    rate *= 2; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">6 <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">7for (auto const &rate : rates) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">8    std::cout << rate << std::endl; </code></pre> <ul style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; padding-left: 32px; list-style-type: disc;"> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">在 C++17 中，经过使用结构化绑定和解构声明：</li> </ul> <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">1for (auto &&[rate, flag] : getRates2()) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">2    std::cout << rate << std::endl; </code></pre> <h3 id="hhowitworks" style="color: inherit; line-height: inherit; padding: 0px; margin: 1.5em 0px; font-weight: bold; font-size: 1.3em; border-bottom: 2px solid rgb(0, 172, 193);"><span style="font-size: inherit; line-height: inherit; margin: 0px; display: inline-block; font-weight: normal; background: rgb(0, 172, 193); color: rgb(255, 255, 255); padding: 3px 10px 0px; border-top-right-radius: 3px; border-top-left-radius: 4px; margin-right: 2px;">How it works…</h3> 以前在 How to do it… 中显示的基于范围的 for 循环的表达式是基础的语法糖，编译器会将其转换为其它的东西。在 C++17 以前，编译器生成的代码以下所示： <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">1{ <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">2    auto &&__range = range_expression; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">3    for (auto __begin = begin_expr, __end = end_expr; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">4         __begin != __end; ++__begin) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">5    { <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">6        range_declaration = *__begin; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">7        loop_statement <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">8    } <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">9} </code></pre> 代码中的 begin_expr 和 end_expr 依赖于这个范围的类型： <ul style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; padding-left: 32px; list-style-type: disc;"> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">对于 C 风格的数组，__range 和 __bound 是数组中元素的个数。</li> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">对于有 begin() 和 end() 成员的类类型（不管它们的类型和可访问性）：__range.begin() 和 __range.end()。</li> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">对于其它类型是 begin(__range) 和 end(__range)，经过参数依赖查找进行肯定。</li> </ul> 须要注意的是，若是一个类包含名为 begin 或 end 的任何成员（函数，数据成员或枚举器），不管它们的类型和可访问性，它们都将被选为 begin_expr 和 end_expr。所以，这样的类类型不能使用基于范围 for 循环。 在 C++17 中，编译器生成的代码略微不一样： <pre style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><code class="cpp language-cpp hljs" style="overflow-wrap: break-word; margin: 0px 2px; line-height: 18px; font-size: 14px; font-weight: normal; word-spacing: 0px; letter-spacing: 0px; font-family: Consolas, Inconsolata, Courier, monospace; border-radius: 0px; overflow-x: auto; background: rgb(29, 31, 33); color: rgb(197, 200, 198); padding: 0.5em; display: block !important; white-space: pre !important; word-wrap: normal !important; word-break: normal !important; overflow: auto !important;"><span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 1{ <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 2    auto &&__range = range_expression; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 3    auto __begin = begin_expr; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 4    auto __end = end_expr; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 5    for (; __begin != __end; ++__begin) <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 6    { <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 7        range_declaration = *__begin; <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 8        loop_statement <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;"> 9    } <span class="linenum hljs-number" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; color: rgb(222, 147, 95); padding-right: 20px; word-spacing: 0px; word-wrap: inherit !important; word-break: inherit !important;">10} </code></pre> 新标准移除了 begin 表达式和 end 表达式必须拥有同一类型的约束。end 表达式再也不须要是一个实际的迭代器，可是它必须可以与迭代器进行不等式比较。 这样作的好处是范围能够由谓词分隔。 <h3 id="hseealso" style="color: inherit; line-height: inherit; padding: 0px; margin: 1.5em 0px; font-weight: bold; font-size: 1.3em; border-bottom: 2px solid rgb(0, 172, 193);"><span style="font-size: inherit; line-height: inherit; margin: 0px; display: inline-block; font-weight: normal; background: rgb(0, 172, 193); color: rgb(255, 255, 255); padding: 3px 10px 0px; border-top-right-radius: 3px; border-top-left-radius: 4px; margin-right: 2px;">See also</h3> <ul style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; padding-left: 32px; list-style-type: disc;"> <li style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px; margin-bottom: 0.5em;">为自定义类型启用基于范围的 for 循环</li> </ul> - - - End - - - <hr style="font-size: inherit; color: inherit; line-height: inherit; padding: 0px; height: 1px; margin: 1.5rem 0px; border-right: none; border-bottom: none; border-left: none; border-image: initial; border-top: 1px dashed rgb(165, 165, 165);"> <figure style="font-size: inherit; color: inherit; line-height: inherit; margin: 0px; padding: 0px;"><img src="https://lzl678-1253937507.cos.ap-chengdu.myqcloud.com/common/wechat-qcode.jpg" alt="欢迎扫码订阅个人微信公众号，阅读其它相关文章。" title="欢迎扫码订阅个人微信公众号，阅读其它相关文章。" style="font-size: inherit; color: inherit; line-height: inherit; padding: 0px; display: block; margin: 0px auto; max-width: 100%;"><figcaption style="line-height: inherit; margin: 0px; padding: 0px; margin-top: 10px; text-align: center; color: rgb(153, 153, 153); font-size: 0.7em;">欢迎扫码订阅个人微信公众号，阅读其它相关文章。</figcaption></figure> <blockquote style="line-height: inherit; display: block; padding: 15px 15px 15px 1rem; font-size: 0.9em; margin: 1em 0px; color: rgb(129, 145, 152); border-left: 6px solid rgb(220, 230, 240); background: rgb(242, 247, 251); overflow: auto; overflow-wrap: normal; word-break: normal;"> 本文做者： Lzl678 本文连接： <a href="https://www.cnblogs.com/Lzl678/p/10940182.html" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; text-decoration: none; color: rgb(30, 107, 184); overflow-wrap: break-word;">https://www.cnblogs.com/Lzl678/p/10940182.html</a> 版权声明：本博客全部文章除特别声明外，均采用 <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" style="font-size: inherit; line-height: inherit; margin: 0px; padding: 0px; text-decoration: none; color: rgb(30, 107, 184); overflow-wrap: break-word;">CC BY-NC-SA 4.0</a> 许可协议。转载请注明出处！ </blockquote></div>html