C++中友元（友元函數和友元類）的用法和功能

時間 2020-05-14

標籤 c++ 函數用法功能欄目 C&C++ 简体版

原文原文鏈接

採用類的機制後實現了數據的隱藏與封裝，類的數據成員通常定義爲私有成員，成員函數通常定義爲公有的，依此提供類與外界間的通訊接口。可是，有時須要定義一些函數，這些函數不是類的一部分，但又須要頻繁地訪問類的數據成員，這時能夠將這些函數定義爲該函數的友元函數。除了友元函數外，還有友元類，二者統稱爲友元。友元的做用是提升了程序的運行效率（即減小了類型檢查和安全性檢查等都須要時間開銷），但它破壞了類的封裝性和

>>阅读原文<<

1. C++友元的用法(友元函數、友元類和友元成員函數)
2. [C/C++] 友元函數和友元類
3. C++ 類(友元函數和友元類)
4. c++-友元函數和友元類
5. c++ 友元函數和友元類
6. C++——友元函數和友元類
7. 友元(友元函數、友元類和友元成員函數) C++
8. 友元函數和友元類
9. c++友元全局函數、友元成員函數、友元類
10. C++友元函數、友元類、友元成員函數
更多相關文章...
• RSS , <link>, 和 <description> 元素</a> - <a href="http://www.voidme.com/rss" target="_blank" title="RSS 教程"> RSS 教程</a></li> <li> • <a href="http://www.voidme.com/rss/rss-tag-title-link-description-channel" target="_blank" title="RSS <title>, <link>, 和 <description> 元素"> RSS <title>, <link>, 和 <description> 元素</a> - <a href="http://www.voidme.com/rss" target="_blank" title="RSS 教程"> RSS 教程</a></li> <li> • <a href="http://www.voidme.com/content/ifwlmsduwy-bsx" target="_blank" title="C# 中 foreach 遍歷的用法"> C# 中 foreach 遍歷的用法</a> </li> <li> • <a href="http://www.voidme.com/content/fykxkspdpu-bsx" target="_blank" title="TiDB 在摩拜單車在線數據業務的應用和實踐"> TiDB 在摩拜單車在線數據業務的應用和實踐</a> </li> </ul> <div class="margin-top-20"></div> <div> <div></div> </div> <div class="margin-top-20"></div> <div class="relative">相關標籤/搜索</div> <ul> <a target='_blank' href="http://hk.javashuo.com/tag/%E4%B8%AD%E5%85%83" title="中元"> <span class="new-label">中元</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E5%8F%8B%E6%83%85" title="友情"> <span class="new-label">友情</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E5%A5%BD%E5%8F%8B" title="好友"> <span class="new-label">好友</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E7%90%83%E5%8F%8B" title="球友"> <span class="new-label">球友</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E8%A6%AA%E5%8F%8B" title="親友"> <span class="new-label">親友</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E8%A8%AA%E5%8F%8B" title="訪友"> <span class="new-label">訪友</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E7%9B%8A%E5%8F%8B" title="益友"> <span class="new-label">益友</span></a> <a target='_blank' href="http://hk.javashuo.com/tag/%E7%94%B7%E5%8F%8B" title="男友"> <span class="new-label">男友</span></a> <a target='_blank' href="http://hk.javashuo.com/column/c " title="C&C++"> <span class="new-label">C&C++</span></a> <a href="http://www.voidme.com/xlink" target="_blank" title="XLink 和 XPointer 教程"> <span class="new-label">XLink 和 XPointer 教程</span></a> <a href="http://www.voidme.com/csharp" target="_blank" title="C#教程"> <span class="new-label">C#教程</span></a> <a href="http://www.voidme.com/mybatis" target="_blank" title="MyBatis教程"> <span class="new-label">MyBatis教程</span></a> <a href="http://www.voidme.com/tag/c#" target="_blank" title="C#"> <span class="new-label">C#</span></a> <a href="http://www.voidme.com/tag/應用" target="_blank" title="應用"> <span class="new-label">應用</span></a> <a href="http://www.voidme.com/tag/算法" target="_blank" title="算法"> <span class="new-label">算法</span></a> </ul> </div> <div class="article_social"> <div class="article_like"> <div class="circle circle-like" id="my_zan" data_id="eEvIVb6"></div> </div> <div class="clear"></div> <div class="share"> <span class="share-left bdsharebuttonbox" data-tag="share_1"> <a href="#" class="bds_more icon-share" data-cmd="more"> <span class="bds_count" data-cmd="count" title="累计分享0次">0</span> </a> </span> <div class="share-right action action-share bdsharebuttonbox" data-tag="share_1"> <span class="bdshare"> <a href="#" class="bds_sinaweibo icon-weibo" data-cmd="tsina" title="分享到新浪微博">分享到微博</a> <a href="#" class="bds_weixin icon-wechat" data-cmd="weixin" title="分享到微信">分享到微信</a> <a href="#" class="bds_qq icon-qq" data-cmd="sqq" title="分享到QQ好友">分享到QQ</a> </span> </div> </div> <div class="clear"></div> <div class="bottom_plink huodong-detail-plink-banner clearfix"> </div> </div> <script> $(function () { $("#originfo").text("https://blog.csdn.net/adriano119/article/details/5914443"); $("#originfo").hover(function () { $("#originfo").attr("href", "/link?url=https://blog.csdn.net/adriano119/article/details/5914443"); }, function () { $("#originfo").attr("href", "javascript:void()"); }); }); </script> <script src="http://static2.javashuo.com/static/script/article.js?time=1735430479762" type="text/javascript"></script> </div> <div class="span3 article_right_side"> <div class="right_top"> <div id="right_site_articles" class="article_detail_bg"> <div class="article-part-title"> <span>每日一句</span> </div> <ul class="side_article_list"> 每一个你不满意的现在，都有一个你没有努力的曾经。 </ul> </div><script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>  <ins class="adsbygoogle" style="display:block" data-ad-client="ca-pub-6208739752673518" data-ad-slot="5830279121" data-ad-format="auto" data-full-width-responsive="true"></ins> <script> (adsbygoogle = window.adsbygoogle || []).push({}); </script> <div id="right_site_articles"> <div class="article-part-title"> <span>最新文章</span> </div> <ul class="side_article_list"> <li class="side_article_list_item">1. <a href="http://hk.javashuo.com/article/p-fcahkidz-xh.html" target="_blank" title="字節跳動21屆秋招運營兩輪面試經驗分享"> 字節跳動21屆秋招運營兩輪面試經驗分享 </a> </li> <li class="side_article_list_item">2. <a href="http://hk.javashuo.com/article/p-zdjetmnf-xh.html" target="_blank" title="Java 3 年，25K 多嗎？"> Java 3 年，25K 多嗎？ </a> </li> <li class="side_article_list_item">3. <a href="http://hk.javashuo.com/article/p-zangfdsh-xh.html" target="_blank" title="mysql安裝部署"> mysql安裝部署 </a> </li> <li class="side_article_list_item">4. <a href="http://hk.javashuo.com/article/p-xfxiwazf-xh.html" target="_blank" title="web前端開發中父鏈和子鏈方式實現通信"> web前端開發中父鏈和子鏈方式實現通信 </a> </li> <li class="side_article_list_item">5. <a href="http://hk.javashuo.com/article/p-bdbnqtcr-xh.html" target="_blank" title="3.1.6 spark體系之分佈式計算-scala編程-scala中trait特性"> 3.1.6 spark體系之分佈式計算-scala編程-scala中trait特性 </a> </li> <li class="side_article_list_item">6. <a href="http://hk.javashuo.com/article/p-eoityvck-xh.html" target="_blank" title="dataframe2"> dataframe2 </a> </li> <li class="side_article_list_item">7. <a href="http://hk.javashuo.com/article/p-kvbwgcuy-xh.html" target="_blank" title="ThinkFree在線"> ThinkFree在線 </a> </li> <li class="side_article_list_item">8. <a href="http://hk.javashuo.com/article/p-gylxlozy-xh.html" target="_blank" title="在線畫圖"> 在線畫圖 </a> </li> <li class="side_article_list_item">9. <a href="http://hk.javashuo.com/article/p-hiawqwso-xh.html" target="_blank" title="devtools熱部署"> devtools熱部署 </a> </li> <li class="side_article_list_item">10. <a href="http://hk.javashuo.com/article/p-yiypxcdk-xh.html" target="_blank" title="編譯和鏈接"> 編譯和鏈接 </a> </li> </ul> </div> </div> <div class="operate_zone"> <div id="right_site_articles" class="article_detail_bg margin-top10"> <div class="article-part-title"> <span><a href="/contact" target="_blank">本站公眾號</a></span> </div> <div class="side_article_list user-head"> <span style="color: #5ba607;font-size:14px;"> 歡迎關注本站公眾號,獲取更多信息</span><br/> <img src="http://open.weixin.qq.com/qr/code?username=develong"/> </div> </div> <div id="right_site_articles"> <div class="article-part-title"> <span>相關文章</span> </div> <ul class="side_article_list"> <li class="side_article_list_item">1. <a href="http://hk.javashuo.com/article/p-bgstizzi-mv.html" target="_blank" title="C++友元的用法(友元函數、友元類和友元成員函數)"> C++友元的用法(友元函數、友元類和友元成員函數) </a> </li> <li class="side_article_list_item">2. <a href="http://hk.javashuo.com/article/p-rsiekycg-dx.html" target="_blank" title="[C/C++] 友元函數和友元類"> [C/C++] 友元函數和友元類 </a> </li> <li class="side_article_list_item">3. <a href="http://hk.javashuo.com/article/p-yzqsktvt-dh.html" target="_blank" title="C++ 類(友元函數和友元類)"> C++ 類(友元函數和友元類) </a> </li> <li class="side_article_list_item">4. <a href="http://hk.javashuo.com/article/p-azbxvvkj-kd.html" target="_blank" title="c++-友元函數和友元類"> c++-友元函數和友元類 </a> </li> <li class="side_article_list_item">5. <a href="http://hk.javashuo.com/article/p-urxusglj-tt.html" target="_blank" title="c++ 友元函數和友元類"> c++ 友元函數和友元類 </a> </li> <li class="side_article_list_item">6. <a href="http://hk.javashuo.com/article/p-vpxwecip-tt.html" target="_blank" title="C++——友元函數和友元類"> C++——友元函數和友元類 </a> </li> <li class="side_article_list_item">7. <a href="http://hk.javashuo.com/article/p-cthavvdo-gw.html" target="_blank" title="友元(友元函數、友元類和友元成員函數) C++"> 友元(友元函數、友元類和友元成員函數) C++ </a> </li> <li class="side_article_list_item">8. <a href="http://hk.javashuo.com/article/p-dzevhbyc-ge.html" target="_blank" title="友元函數和友元類"> 友元函數和友元類 </a> </li> <li class="side_article_list_item">9. <a href="http://hk.javashuo.com/article/p-qicwqyqy-sv.html" target="_blank" title="c++友元全局函數、友元成員函數、友元類"> c++友元全局函數、友元成員函數、友元類 </a> </li> <li class="side_article_list_item">10. <a href="http://hk.javashuo.com/article/p-aiieqqde-sv.html" target="_blank" title="C++友元函數、友元類、友元成員函數"> C++友元函數、友元類、友元成員函數 </a> </li> </ul> <div style='padding-left:10px;font-size:14px;padding-bottom:10px;'> <a href='http://hk.javashuo.com/relative/p-ddsaasey-mu.html' target='_blank' title="C++中友元（友元函數和友元類）的用法和功能的相關文章"> >>更多相關文章<< </a> </div> </div> </div> </div> </div> <script type="text/javascript"> $('table').each(function (i) { var size = $(this).children().size(); if (size > 1) { $(this).attr('class', "table table-bordered"); } else if (size == 1) { var e11 = $(this).children(":first"); var e1 = e11[0]; var name = e1.nodeName.toLowerCase(); if ("tbody" == name) { if (e1.children.length > 1) { $(this).attr('class', "table table-bordered"); } else if (e1.children.length == 1) { var e12 = e1.children[0]; var name2 = e12.nodeName.toLowerCase(); if ("tr" == name2) { if (e12.children.length > 1) { $(this).attr('class', "table table-bordered"); } } } } } }); window.page = 0; window.last = 0; window.first = true; resize_article_image('#nei', 550); + (function($){ window._bd_share_config = { common: { "bdText": "【" + $("title").text() + "】" + $(".post-content p:lt(2)").text(), "bdMini": "2", "bdMiniList": false, "bdPic": $(".post-content img:first") ? $(".post-content img:first").attr("src") : "", "bdStyle": "0", "bdSize": "24" }, share: [{ bdCustomStyle: 'http://static2.javashuo.com/static/css/share.css' }], }; with(document) 0[(getElementsByTagName("head")[0] || body).appendChild(createElement("script")).src = "http://bdimg.share.baidu.com/static/api/js/share.js?cdnversion=" + ~ ( - new Date() / 36e5)]; })(window.jQuery); </script> </div> <script type="text/javascript" src="http://static2.javashuo.com/static/plugin/highlight/highlight.pack.js"></script> <link href="http://static2.javashuo.com/static/plugin/highlight/styles/docco.css" media="screen" rel="stylesheet" type="text/css" /> <script type="text/javascript"> $('pre').each(function(i, e) { hljs.highlightBlock(e, "<span class='indent'> </span>", false) }); </script> <div class="footer"> <div class="footer-inner" style="padding-top: 50px;padding-bottom: 50px"> <a href="http://hk.javashuo.com/contact" target="_blank">聯繫我們</a> <a href="http://hk.javashuo.com/search">最近搜索</a> <a href="http://hk.javashuo.com/recent">最新文章</a> <script type="text/javascript" src="https://v1.cnzz.com/z_stat.php?id=1279585947&web_id=1279585947"></script> <a href="https://beian.miit.gov.cn/" target="_blank">沪ICP备13005482号-10</a> <a href="http://www.voidme.com/mybatis" target="_blank">MyBatis教程</a> <a href="http://www.voidme.com/sql" target="_blank">SQL 教程</a> <a href="http://www.voidme.com/mysql" target="_blank">MySQL教程</a> <a href="http://www.voidme.com/java" target="_blank">Java 教程</a> <a href="http://www.voidme.com/thymeleaf" target="_blank">Thymeleaf 教程</a> <a href="http://www.voidme.com/hibernate" target="_blank">Hibernate教程</a> <a href="http://www.voidme.com/spring" target="_blank">Spring教程 </a> <a href="http://www.voidme.com/redis" target="_blank">Redis教程 </a> </div> <div style="display:none;"> <script> var _hmt = _hmt || []; (function() { var hm = document.createElement("script"); hm.src = "https://hm.baidu.com/hm.js?2936bf9a19a3d5abb5c9c726af070b7c"; var s = document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(hm, s); })(); </script> </div> </div> <script type="text/javascript" src="http://static2.javashuo.com/static/script/tip.js?time=1735430479762" async></script> </body> </html>