{"id":97046,"date":"2026-08-28T23:40:52","date_gmt":"2026-08-28T15:40:52","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/97046.html"},"modified":"2026-08-28T23:40:52","modified_gmt":"2026-08-28T15:40:52","slug":"%e3%80%90%e3%80%8aeffective-c%e3%80%8b%e7%b2%be%e8%af%bb%e3%80%91%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/97046.html","title":{"rendered":"\u3010\u300aEffective C++\u300b\u7cbe\u8bfb\u3011\u5b9e\u73b0"},"content":{"rendered":"<\/p>\n<h4>\u7cbe\u8bfb\u300aEffective C&#043;&#043;\u300b\u7b2c\u4e94\u7ae0&#xff1a;\u5b9e\u73b0<\/h4>\n<ul>\n<li>&#x1f3af; \u524d\u8a00<\/li>\n<li>\u4e00\u3001\u6761\u6b3e25&#xff1a;\u8003\u8651\u5199\u51fa\u4e00\u4e2a\u4e0d\u629b\u5f02\u5e38\u7684 swap \u51fd\u6570<\/li>\n<li>\n<ul>\n<li>1. \u9ed8\u8ba4 swap \u4e3a\u4ec0\u4e48\u4e0d\u591f\u597d<\/li>\n<li>2. \u4e09\u5c42 swap \u7ed3\u6784<\/li>\n<li>3. \u5ba2\u6237\u8c03\u7528 swap \u7684\u6b63\u786e\u59ff\u52bf<\/li>\n<li>4. \u6210\u5458 swap \u7edd\u4e0d\u80fd\u629b\u5f02\u5e38<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;\u4e3a\u4ec0\u4e48 C&#043;&#043; \u4e0d\u5141\u8bb8\u504f\u7279\u5316 function template<\/li>\n<\/ul>\n<\/li>\n<li>\u4e8c\u3001\u6761\u6b3e26&#xff1a;\u5c3d\u53ef\u80fd\u5ef6\u540e\u53d8\u91cf\u5b9a\u4e49\u5f0f\u7684\u51fa\u73b0\u65f6\u95f4<\/li>\n<li>\n<ul>\n<li>1. \u8fc7\u65e9\u5b9a\u4e49\u7684\u6210\u672c<\/li>\n<li>2. \u5faa\u73af\u91cc\u7684\u53d8\u91cf&#xff1a;\u5b9a\u4e49\u5728\u5185\u8fd8\u662f\u5916&#xff1f;<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;\u5ef6\u540e\u5b9a\u4e49\u4e0e RAII \u7684\u5173\u7cfb<\/li>\n<\/ul>\n<\/li>\n<li>\u4e09\u3001\u6761\u6b3e27&#xff1a;\u5c3d\u91cf\u5c11\u505a\u8f6c\u578b\u52a8\u4f5c<\/li>\n<li>\n<ul>\n<li>1. \u56db\u79cd\u65b0\u5f0f\u8f6c\u578b<\/li>\n<li>2. \u8f6c\u578b\u4e0d\u662f&#034;\u544a\u8bc9\u7f16\u8bd1\u5668\u6362\u4e2a\u7c7b\u578b\u770b&#034;\u2014\u2014\u5b83\u771f\u7684\u4f1a\u751f\u6210\u4ee3\u7801<\/li>\n<li>3. \u4e00\u4e2a\u9690\u853d\u7684 bug&#xff1a;\u5728\u6d3e\u751f\u7c7b\u51fd\u6570\u91cc\u8f6c\u578b *this<\/li>\n<li>4. dynamic_cast \u5f88\u6162&#xff0c;\u8981\u907f\u514d\u8fde\u4e32\u4f7f\u7528<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;\u4e3a\u4ec0\u4e48 C&#043;&#043; \u7684\u5bf9\u8c61\u53ef\u4ee5\u6709\u591a\u4e2a\u5730\u5740<\/li>\n<\/ul>\n<\/li>\n<li>\u56db\u3001\u6761\u6b3e28&#xff1a;\u907f\u514d\u8fd4\u56de handles \u6307\u5411\u5bf9\u8c61\u5185\u90e8\u6210\u5206<\/li>\n<li>\n<ul>\n<li>1. const \u6210\u5458\u51fd\u6570\u5374\u80fd\u4fee\u6539\u5bf9\u8c61<\/li>\n<li>2. \u52a0 const \u53ef\u4ee5\u89e3\u51b3\u5c01\u88c5\u95ee\u9898<\/li>\n<li>3. \u60ac\u7a7a handle&#xff08;dangling handles&#xff09;<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;const \u5f15\u7528\u8fd4\u56de\u503c\u4e0e\u4e34\u65f6\u5bf9\u8c61\u751f\u547d\u5468\u671f<\/li>\n<\/ul>\n<\/li>\n<li>\u4e94\u3001\u6761\u6b3e29&#xff1a;\u4e3a&#034;\u5f02\u5e38\u5b89\u5168&#034;\u800c\u52aa\u529b\u662f\u503c\u5f97\u7684<\/li>\n<li>\n<ul>\n<li>1. \u5f02\u5e38\u5b89\u5168\u7684\u4e24\u4e2a\u6761\u4ef6<\/li>\n<li>2. \u7528\u5bf9\u8c61\u7ba1\u7406\u8d44\u6e90\u89e3\u51b3\u6cc4\u6f0f<\/li>\n<li>3. \u4e09\u4e2a\u5f02\u5e38\u5b89\u5168\u4fdd\u8bc1<\/li>\n<li>4. copy-and-swap \u5b9e\u73b0\u5f3a\u70c8\u4fdd\u8bc1<\/li>\n<li>5. \u5f02\u5e38\u5b89\u5168\u662f\u5168\u6709\u6216\u5168\u65e0\u7684<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;copy-and-swap \u4e0e C&#043;&#043;11 \u79fb\u52a8\u8bed\u4e49\u7684\u5173\u7cfb<\/li>\n<\/ul>\n<\/li>\n<li>\u516d\u3001\u6761\u6b3e30&#xff1a;\u900f\u5f7b\u4e86\u89e3 inlining \u7684\u91cc\u91cc\u5916\u5916<\/li>\n<li>\n<ul>\n<li>1. inline \u662f\u7533\u8bf7\u4e0d\u662f\u547d\u4ee4<\/li>\n<li>2. inline \u7684\u6210\u672c&#xff1a;\u4ee3\u7801\u81a8\u80c0<\/li>\n<li>3. \u5373\u4f7f\u7f16\u8bd1\u5668\u613f\u610f inline&#xff0c;\u4e5f\u53ef\u80fd\u751f\u6210 outlined \u526f\u672c<\/li>\n<li>4. inline \u51fd\u6570\u65e0\u6cd5\u968f\u5e93\u5347\u7ea7\u800c\u5347\u7ea7<\/li>\n<li>5. 80-20 \u6cd5\u5219<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;inline \u4e0e template \u7684\u5173\u7cfb<\/li>\n<\/ul>\n<\/li>\n<li>\u4e03\u3001\u6761\u6b3e31&#xff1a;\u5c06\u6587\u4ef6\u95f4\u7684\u7f16\u8bd1\u4f9d\u5b58\u5173\u7cfb\u964d\u81f3\u6700\u4f4e<\/li>\n<li>\n<ul>\n<li>1. \u95ee\u9898&#xff1a;\u6539\u4e00\u4e2a private \u6210\u5458&#xff0c;\u5168\u4e16\u754c\u91cd\u7f16\u8bd1<\/li>\n<li>2. pimpl \u624b\u6cd5&#xff1a;\u58f0\u660e\u4f9d\u5b58\u6027\u66ff\u6362\u5b9a\u4e49\u4f9d\u5b58\u6027<\/li>\n<li>3. \u4e24\u79cd\u89e3\u8026\u624b\u6bb5<\/li>\n<li>\n<ul>\n<li>Handle class&#xff08;\u53e5\u67c4\u7c7b&#xff09;<\/li>\n<li>Interface class&#xff08;\u63a5\u53e3\u7c7b&#xff09;<\/li>\n<\/ul>\n<\/li>\n<li>4. \u5b9e\u8df5\u5efa\u8bae<\/li>\n<li>\u6df1\u5ea6\u601d\u8003&#xff1a;C&#043;&#043;20 modules \u662f\u5426\u7ec8\u7ed3\u4e86 pimpl<\/li>\n<\/ul>\n<\/li>\n<li>\u516b\u3001\u77e5\u8bc6\u7ed3\u6784\u56fe<\/li>\n<li>&#x1f4dd; \u603b\u7ed3<\/li>\n<li>&#x1f4da; \u53c2\u8003\u8d44\u6599<\/li>\n<li>&#x1f3f7;\ufe0f \u63a8\u8350\u6807\u7b7e<\/li>\n<\/ul>\n<p>\u672c\u6587\u662f\u6211\u7cbe\u8bfb\u300aEffective C&#043;&#043;&#xff08;\u7b2c\u4e09\u7248&#xff09;\u300b\u7b2c\u4e94\u7ae0&#034;\u5b9e\u73b0&#034;&#xff08;\u6761\u6b3e25-31&#xff09;\u7684\u5b66\u4e60\u7b14\u8bb0\u3002\u5982\u679c\u8bf4\u7b2c\u56db\u7ae0\u8c08\u7684\u662f&#034;\u63a5\u53e3\u957f\u4ec0\u4e48\u6837&#034;&#xff0c;\u8fd9\u4e00\u7ae0\u5c31\u94bb\u8fdb\u4e86\u4ee3\u7801\u5185\u90e8\u2014\u2014\u53d8\u91cf\u8be5\u4ec0\u4e48\u65f6\u5019\u5b9a\u4e49\u3001\u8f6c\u578b\u6709\u4ec0\u4e48\u9690\u85cf\u4ee3\u4ef7\u3001\u5f02\u5e38\u629b\u51fa\u540e\u8c01\u6765\u6536\u62fe\u70c2\u644a\u5b50\u3001inline\u5230\u5e95\u662f\u94f6\u5f39\u8fd8\u662f\u9677\u9631\u3001\u6539\u4e00\u4e2aprivate\u6210\u5458\u4e3a\u4ec0\u4e48\u8981\u91cd\u7f16\u6574\u4e2a\u4e16\u754c\u3002\u5168\u662f\u5199\u4ee3\u7801\u65f6\u5929\u5929\u78b0\u5230\u4f46\u672a\u5fc5\u60f3\u900f\u7684\u95ee\u9898&#xff0c;\u6709\u4e0d\u5bf9\u7684\u5730\u65b9\u6b22\u8fce\u8bc4\u8bba\u533a\u6307\u6b63&#xff5e;<\/p>\n<hr \/>\n<h2>&#x1f3af; \u524d\u8a00<\/h2>\n<p>\u7b2c\u56db\u7ae0\u8bb2\u8bbe\u8ba1\u4e0e\u58f0\u660e&#xff0c;\u8ba8\u8bba\u7684\u662f&#034;\u63a5\u53e3\u5e94\u8be5\u957f\u4ec0\u4e48\u6837&#034;\u3002\u8fd9\u4e00\u7ae0\u5f80\u4e0b\u8d70\u4e00\u5c42&#xff0c;\u8c08\u5b9e\u73b0&#xff08;Implementations&#xff09;\u2014\u2014\u5f53\u7c7b\u548c\u51fd\u6570\u7684\u8bbe\u8ba1\u786e\u5b9a\u4e4b\u540e&#xff0c;\u5199\u4ee3\u7801\u65f6\u90a3\u4e9b&#034;\u770b\u8d77\u6765\u65e0\u5173\u7d27\u8981&#034;\u7684\u9009\u62e9&#xff0c;\u600e\u4e48\u6084\u6084\u5f71\u54cd\u7a0b\u5e8f\u7684\u6548\u7387\u3001\u5065\u58ee\u6027\u548c\u53ef\u7ef4\u62a4\u6027\u3002<\/p>\n<p>Scott Meyers \u5728\u8fd9\u4e00\u7ae0\u8986\u76d6\u7684\u4e03\u4e2a\u6761\u6b3e&#xff0c;\u6211\u8bfb\u5b8c\u540e\u611f\u89c9\u5b83\u4eec\u5176\u5b9e\u56f4\u7ed5\u4e24\u4e2a\u4e3b\u9898&#xff1a;<\/p>\n<li>\u522b\u4e3a\u4e0d\u5fc5\u8981\u7684\u4e1c\u897f\u4ed8\u8d39&#xff1a;\u5ef6\u540e\u53d8\u91cf\u5b9a\u4e49&#xff08;\u6761\u6b3e26&#xff09;\u3001\u51cf\u5c11\u8f6c\u578b&#xff08;\u6761\u6b3e27&#xff09;\u3001\u8c28\u614e inline&#xff08;\u6761\u6b3e30&#xff09;\u3001\u964d\u4f4e\u7f16\u8bd1\u4f9d\u5b58&#xff08;\u6761\u6b3e31&#xff09;<\/li>\n<li>\u51fa\u4e86\u95ee\u9898\u522b\u7559\u70c2\u644a\u5b50&#xff1a;swap \u4e0d\u629b\u5f02\u5e38&#xff08;\u6761\u6b3e25&#xff09;\u3001\u522b\u8fd4\u56de\u60ac\u7a7a handle&#xff08;\u6761\u6b3e28&#xff09;\u3001\u5f02\u5e38\u5b89\u5168\u4fdd\u8bc1&#xff08;\u6761\u6b3e29&#xff09;<\/li>\n<p>\u4e0b\u9762\u6309\u6761\u6b3e\u987a\u5e8f\u8bb0\u5f55\u6211\u7684\u5b66\u4e60\u8fc7\u7a0b\u3002<\/p>\n<hr \/>\n<h2>\u4e00\u3001\u6761\u6b3e25&#xff1a;\u8003\u8651\u5199\u51fa\u4e00\u4e2a\u4e0d\u629b\u5f02\u5e38\u7684 swap \u51fd\u6570<\/h2>\n<p>Consider support for a non-throwing swap.<\/p>\n<h3>1. \u9ed8\u8ba4 swap \u4e3a\u4ec0\u4e48\u4e0d\u591f\u597d<\/h3>\n<p>std::swap \u7684\u9ed8\u8ba4\u5b9e\u73b0\u5f88\u6734\u7d20&#xff1a;<\/p>\n<p><span class=\"token keyword\">namespace<\/span> std <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">template<\/span><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">typename<\/span> <span class=\"token class-name\">T<\/span><span class=\"token operator\">&gt;<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>T<span class=\"token operator\">&amp;<\/span> a<span class=\"token punctuation\">,<\/span> T<span class=\"token operator\">&amp;<\/span> b<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    T <span class=\"token function\">temp<\/span><span class=\"token punctuation\">(<\/span>a<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u62f7\u8d1d a<\/span><br \/>\n    a <span class=\"token operator\">&#061;<\/span> b<span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/\/ \u62f7\u8d1d b \u5230 a<\/span><br \/>\n    b <span class=\"token operator\">&#061;<\/span> temp<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u62f7\u8d1d temp \u5230 b<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5bf9\u666e\u901a\u7c7b\u578b\u6ca1\u95ee\u9898&#xff0c;\u4f46\u5982\u679c\u4f60\u7684\u7c7b\u7528\u4e86 pimpl \u624b\u6cd5&#xff08;pointer to implementation&#xff0c;\u6761\u6b3e31\u8be6\u89e3&#xff09;&#xff0c;\u9ed8\u8ba4 swap \u5c31\u53d8\u6210\u4e86\u707e\u96be\u2014\u2014\u5b83\u4f1a\u590d\u5236\u4e09\u4e2a Widget \u5bf9\u8c61&#xff0c;\u8fde\u5e26\u590d\u5236\u4e09\u4e2a WidgetImpl \u5bf9\u8c61&#xff0c;\u800c\u5b9e\u9645\u4e0a\u4f60\u53ea\u9700\u8981\u4ea4\u6362\u4e24\u4e2a\u6307\u9488\u3002<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">WidgetImpl<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> a<span class=\"token punctuation\">,<\/span> b<span class=\"token punctuation\">,<\/span> c<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>vector<span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">double<\/span><span class=\"token operator\">&gt;<\/span> v<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u6570\u636e\u5f88\u591a&#xff0c;\u590d\u5236\u5f88\u6162<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Widget<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">Widget<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> Widget<span class=\"token operator\">&amp;<\/span> rhs<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    Widget<span class=\"token operator\">&amp;<\/span> <span class=\"token keyword\">operator<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> Widget<span class=\"token operator\">&amp;<\/span> rhs<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token operator\">*<\/span>pImpl <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">*<\/span>rhs<span class=\"token punctuation\">.<\/span>pImpl<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u590d\u5236\u6574\u4e2a WidgetImpl<\/span><br \/>\n        <span class=\"token keyword\">return<\/span> <span class=\"token operator\">*<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    WidgetImpl<span class=\"token operator\">*<\/span> pImpl<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h3>2. \u4e09\u5c42 swap \u7ed3\u6784<\/h3>\n<p>Meyers \u7ed9\u51fa\u7684\u89e3\u6cd5\u662f\u4e00\u5957&#034;\u4e09\u5c42\u7ed3\u6784&#034;&#xff1a;<\/p>\n<p>\u7b2c\u4e00\u5c42&#xff1a;public \u6210\u5458 swap<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Widget<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token keyword\">void<\/span> <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>Widget<span class=\"token operator\">&amp;<\/span> other<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">using<\/span> std<span class=\"token double-colon punctuation\">::<\/span>swap<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>pImpl<span class=\"token punctuation\">,<\/span> other<span class=\"token punctuation\">.<\/span>pImpl<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u53ea\u4ea4\u6362\u6307\u9488<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u7b2c\u4e8c\u5c42&#xff1a;\u540c\u547d\u540d\u7a7a\u95f4\u7684 non-member swap<\/p>\n<p><span class=\"token keyword\">namespace<\/span> WidgetStuff <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">template<\/span><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">typename<\/span> <span class=\"token class-name\">T<\/span><span class=\"token operator\">&gt;<\/span><br \/>\n<span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Widget<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">template<\/span><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">typename<\/span> <span class=\"token class-name\">T<\/span><span class=\"token operator\">&gt;<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>Widget<span class=\"token operator\">&lt;<\/span>T<span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> a<span class=\"token punctuation\">,<\/span> Widget<span class=\"token operator\">&lt;<\/span>T<span class=\"token operator\">&gt;<\/span><span class=\"token operator\">&amp;<\/span> b<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    a<span class=\"token punctuation\">.<\/span><span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>b<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u8c03\u7528\u6210\u5458 swap<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u7b2c\u4e09\u5c42&#xff1a;\u9488\u5bf9 class&#xff08;\u975e template&#xff09;\u7684 std::swap \u7279\u5316<\/p>\n<p><span class=\"token keyword\">namespace<\/span> std <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">template<\/span><span class=\"token operator\">&lt;<\/span><span class=\"token operator\">&gt;<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <span class=\"token generic-function\"><span class=\"token function\">swap<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>Widget<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>Widget<span class=\"token operator\">&amp;<\/span> a<span class=\"token punctuation\">,<\/span> Widget<span class=\"token operator\">&amp;<\/span> b<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    a<span class=\"token punctuation\">.<\/span><span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>b<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e3a\u4ec0\u4e48\u9700\u8981\u4e09\u5c42&#xff1f;\u56e0\u4e3a C&#043;&#043; \u7684\u540d\u79f0\u67e5\u627e\u89c4\u5219\u5f88\u5fae\u5999&#xff1a;<\/p>\n<ul>\n<li>non-member \u7248\u672c\u8ba9 ADL&#xff08;\u5b9e\u53c2\u4f9d\u8d56\u67e5\u627e&#xff09; \u80fd\u5728 Widget \u6240\u5728\u547d\u540d\u7a7a\u95f4\u627e\u5230\u4e13\u5c5e swap<\/li>\n<li>std::swap \u7279\u5316\u8ba9\u90a3\u4e9b&#034;\u8ff7\u9014\u7a0b\u5e8f\u5458&#034;\u5199 std::swap(obj1, obj2) \u65f6\u4e5f\u80fd\u547d\u4e2d\u9ad8\u6548\u7248\u672c<\/li>\n<li>\u5bf9 class template \u4e0d\u80fd\u504f\u7279\u5316 function template&#xff0c;\u4e5f\u4e0d\u80fd\u5f80 std \u91cc\u52a0\u65b0\u91cd\u8f7d&#xff0c;\u6240\u4ee5\u53ea\u80fd\u9760\u547d\u540d\u7a7a\u95f4\u91cc\u7684 non-member \u7248\u672c<\/li>\n<\/ul>\n<h3>3. \u5ba2\u6237\u8c03\u7528 swap \u7684\u6b63\u786e\u59ff\u52bf<\/h3>\n<p><span class=\"token keyword\">template<\/span><span class=\"token operator\">&lt;<\/span><span class=\"token keyword\">typename<\/span> <span class=\"token class-name\">T<\/span><span class=\"token operator\">&gt;<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <span class=\"token function\">doSomething<\/span><span class=\"token punctuation\">(<\/span>T<span class=\"token operator\">&amp;<\/span> obj1<span class=\"token punctuation\">,<\/span> T<span class=\"token operator\">&amp;<\/span> obj2<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">using<\/span> std<span class=\"token double-colon punctuation\">::<\/span>swap<span class=\"token punctuation\">;<\/span>       <span class=\"token comment\">\/\/ \u8ba9 std::swap \u53ef\u89c1<\/span><br \/>\n    <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>obj1<span class=\"token punctuation\">,<\/span> obj2<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>      <span class=\"token comment\">\/\/ \u4e0d\u5e26\u547d\u540d\u7a7a\u95f4\u4fee\u9970&#xff0c;\u8ba9\u7f16\u8bd1\u5668\u6311\u6700\u4f73\u7248\u672c<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5173\u952e&#xff1a;\u5148 using std::swap&#xff0c;\u7136\u540e\u88f8\u8c03 swap\u3002\u8fd9\u6837\u7f16\u8bd1\u5668\u4f1a\u4f18\u5148\u627e T \u4e13\u5c5e\u7248\u672c&#xff0c;\u627e\u4e0d\u5230\u624d fallback \u5230 std::swap\u3002\u5343\u4e07\u522b\u5199 std::swap(obj1, obj2)&#xff0c;\u90a3\u4f1a\u5f3a\u8feb\u7f16\u8bd1\u5668\u53ea\u8ba4 std \u91cc\u7684\u7248\u672c\u3002<\/p>\n<h3>4. \u6210\u5458 swap \u7edd\u4e0d\u80fd\u629b\u5f02\u5e38<\/h3>\n<p>\u8fd9\u662f\u8fd9\u6761\u6761\u6b3e\u6700\u6838\u5fc3\u7684\u7ea6\u675f\u3002swap \u662f\u5f02\u5e38\u5b89\u5168\u7f16\u7a0b&#xff08;\u6761\u6b3e29&#xff09;\u7684\u810a\u67f1\u2014\u2014copy-and-swap \u7b56\u7565\u4f9d\u8d56&#034;swap \u4e00\u5b9a\u6210\u529f&#034;\u624d\u80fd\u4fdd\u8bc1&#034;\u8981\u4e48\u5168\u6539\u3001\u8981\u4e48\u4e0d\u6539&#034;\u3002\u800c\u9ad8\u6548 swap \u901a\u5e38\u53ea\u64cd\u4f5c\u5185\u7f6e\u7c7b\u578b&#xff08;\u6307\u9488\u3001\u6574\u6570&#xff09;&#xff0c;\u5185\u7f6e\u7c7b\u578b\u64cd\u4f5c\u672c\u6765\u5c31\u4e0d\u4f1a\u629b\u5f02\u5e38&#xff0c;\u6240\u4ee5\u8fd9\u4e2a\u7ea6\u675f\u662f\u81ea\u7136\u7684\u3002<\/p>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;\u4e3a\u4ec0\u4e48 C&#043;&#043; \u4e0d\u5141\u8bb8\u504f\u7279\u5316 function template<\/h3>\n<p>Q&#xff1a;\u6761\u6b3e\u8bf4&#034;\u53ef\u4ee5\u5168\u7279\u5316 std::swap&#xff0c;\u4f46\u4e0d\u80fd\u504f\u7279\u5316 function template&#xff0c;\u4e5f\u4e0d\u80fd\u5f80 std \u52a0\u91cd\u8f7d&#034;&#xff0c;\u8fd9\u4e9b\u89c4\u5219\u80cc\u540e\u7684\u539f\u56e0\u662f\u4ec0\u4e48&#xff1f;<\/p>\n<p>\u8fd9\u6d89\u53ca C&#043;&#043; \u6a21\u677f\u91cd\u8f7d\u51b3\u8bae\u7684\u8bbe\u8ba1\u54f2\u5b66&#xff1a;<\/p>\n<table>\n<tr>\u64cd\u4f5c\u662f\u5426\u5408\u6cd5\u539f\u56e0<\/tr>\n<tbody>\n<tr>\n<td>\u5168\u7279\u5316 template&lt;&gt; void swap&lt;Widget&gt;(&#8230;)<\/td>\n<td>\u2705 \u5408\u6cd5<\/td>\n<td>\u4e3a\u7279\u5b9a\u7c7b\u578b\u63d0\u4f9b\u7cbe\u786e\u66ff\u6362&#xff0c;\u4e0d\u5f71\u54cd\u91cd\u8f7d\u51b3\u8bae<\/td>\n<\/tr>\n<tr>\n<td>\u504f\u7279\u5316 template&lt;typename T&gt; void swap&lt;Widget&lt;T&gt;&gt;(&#8230;)<\/td>\n<td>\u274c \u4e0d\u5408\u6cd5<\/td>\n<td>\u51fd\u6570\u6a21\u677f\u4e0d\u652f\u6301\u504f\u7279\u5316&#xff08;\u53ea\u6709\u7c7b\u6a21\u677f\u652f\u6301&#xff09;&#xff0c;\u8fd9\u662f\u8bed\u8a00\u89c4\u5219<\/td>\n<\/tr>\n<tr>\n<td>\u5728 std \u5185\u52a0\u65b0\u91cd\u8f7d template&lt;typename T&gt; void swap(Widget&lt;T&gt;&amp;, &#8230;)<\/td>\n<td>\u274c \u672a\u5b9a\u4e49\u884c\u4e3a<\/td>\n<td>std \u547d\u540d\u7a7a\u95f4\u4fdd\u7559\u7ed9\u6807\u51c6\u5e93&#xff0c;\u7528\u6237\u81a8\u80c0\u5b83\u53ef\u80fd\u7834\u574f\u6807\u51c6\u5e93\u5b9e\u73b0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4e3a\u4ec0\u4e48\u51fd\u6570\u6a21\u677f\u4e0d\u652f\u6301\u504f\u7279\u5316&#xff1f;\u6838\u5fc3\u539f\u56e0\u662f\u91cd\u8f7d\u548c\u7279\u5316\u7684\u4ea4\u4e92\u4f1a\u5bfc\u81f4\u53cd\u76f4\u89c9\u7684\u51b3\u8bae\u7ed3\u679c\u3002C&#043;&#043; \u6807\u51c6\u59d4\u5458\u4f1a\u8ba4\u4e3a&#xff0c;\u5982\u679c\u5141\u8bb8\u51fd\u6570\u6a21\u677f\u504f\u7279\u5316&#xff0c;\u7a0b\u5e8f\u5458\u5f88\u96be\u9884\u6d4b\u7f16\u8bd1\u5668\u5230\u5e95\u9009\u62e9\u4e86\u4e3b\u6a21\u677f\u3001\u504f\u7279\u5316\u8fd8\u662f\u666e\u901a\u91cd\u8f7d\u3002\u4e0e\u5176\u5f15\u5165\u590d\u6742\u7684\u4f18\u5148\u7ea7\u89c4\u5219&#xff0c;\u4e0d\u5982\u76f4\u63a5\u7981\u6b62&#xff0c;\u5f15\u5bfc\u5927\u5bb6\u7528&#034;\u547d\u540d\u7a7a\u95f4 non-member \u51fd\u6570 &#043; ADL&#034;\u7684\u65b9\u5f0f\u89e3\u51b3\u2014\u2014\u8fd9\u4e5f\u6b63\u662f Meyers \u63a8\u8350\u7684\u505a\u6cd5\u3002<\/p>\n<p>\u73b0\u4ee3 C&#043;&#043;&#xff08;C&#043;&#043;11 \u4e4b\u540e&#xff09;\u4e2d std::swap \u81ea\u8eab\u5df2\u7ecf\u57fa\u4e8e\u79fb\u52a8\u8bed\u4e49\u5b9e\u73b0&#xff0c;\u5bf9\u6709\u79fb\u52a8\u6784\u9020\u51fd\u6570\u7684\u7c7b\u578b\u9ed8\u8ba4\u5c31\u5f88\u9ad8\u6548\u3002\u4f46\u5bf9\u4e8e pimpl \u7c7b&#xff0c;\u624b\u5199 swap \u4ecd\u7136\u6709\u4ef7\u503c\u2014\u2014\u79fb\u52a8\u8bed\u4e49\u540c\u6837\u8981\u8d70\u6307\u9488\u4ea4\u6362&#xff0c;\u800c\u4f60\u65e0\u6cd5\u4fdd\u8bc1\u7f16\u8bd1\u5668\u751f\u6210\u7684 move \u4e00\u5b9a\u6700\u4f18\u3002<\/p>\n<p>&#x1f4d6; swap \u7684\u4e09\u5c42\u7ed3\u6784\u4e0d\u662f\u4eea\u5f0f&#xff0c;\u800c\u662f\u4e3a\u4e86\u5728 C&#043;&#043; \u540d\u79f0\u67e5\u627e\u7684\u8ff7\u5bab\u4e2d\u786e\u4fdd&#034;\u6700\u9ad8\u6548\u7248\u672c\u603b\u80fd\u88ab\u8c03\u7528&#034;\u3002\u6210\u5458 swap \u7684 no-throw \u4fdd\u8bc1\u662f\u5f02\u5e38\u5b89\u5168\u7f16\u7a0b\u7684\u57fa\u77f3\u3002<\/p>\n<hr \/>\n<h2>\u4e8c\u3001\u6761\u6b3e26&#xff1a;\u5c3d\u53ef\u80fd\u5ef6\u540e\u53d8\u91cf\u5b9a\u4e49\u5f0f\u7684\u51fa\u73b0\u65f6\u95f4<\/h2>\n<p>Postpone variable definitions as long as possible.<\/p>\n<h3>1. \u8fc7\u65e9\u5b9a\u4e49\u7684\u6210\u672c<\/h3>\n<p>\u53ea\u8981\u4f60\u5b9a\u4e49\u4e86\u4e00\u4e2a\u5e26\u6784\u9020\/\u6790\u6784\u51fd\u6570\u7684\u53d8\u91cf&#xff0c;\u63a7\u5236\u6d41\u5230\u8fbe\u5b9a\u4e49\u5f0f\u65f6\u5c31\u8981\u4ed8\u6784\u9020\u6210\u672c&#xff0c;\u79bb\u5f00\u4f5c\u7528\u57df\u65f6\u8981\u4ed8\u6790\u6784\u6210\u672c\u2014\u2014\u5373\u4f7f\u8fd9\u4e2a\u53d8\u91cf\u6700\u7ec8\u6ca1\u88ab\u7528\u5230\u3002<\/p>\n<p>\u4e66\u91cc\u7ed9\u4e86\u4e00\u4e2a\u52a0\u5bc6\u51fd\u6570\u7684\u4f8b\u5b50\u3002\u5982\u679c\u5bc6\u7801\u592a\u77ed\u629b\u5f02\u5e38&#xff0c;\u8fc7\u65e9\u5b9a\u4e49\u7684 encrypted \u5c31\u767d\u6784\u9020\u767d\u6790\u6784\u4e86&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u4e0d\u4f73&#xff1a;encrypted \u5728\u957f\u5ea6\u68c0\u67e5\u4e4b\u524d\u5b9a\u4e49<\/span><br \/>\nstd<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">encryptPassword<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> password<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string encrypted<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5148 default \u6784\u9020<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>password<span class=\"token punctuation\">.<\/span><span class=\"token function\">length<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> MinimumPasswordLength<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">throw<\/span> std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">logic_error<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;Password is too short&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    encrypted <span class=\"token operator\">&#061;<\/span> password<span class=\"token punctuation\">;<\/span>   <span class=\"token comment\">\/\/ \u518d\u8d4b\u503c\u2014\u2014\u6761\u6b3e4\u8bf4\u8fc7\u8fd9\u6bd4\u76f4\u63a5\u6784\u9020\u4f4e\u6548<\/span><br \/>\n    <span class=\"token function\">encrypt<\/span><span class=\"token punctuation\">(<\/span>encrypted<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> encrypted<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u6700\u4f73&#xff1a;\u5ef6\u540e\u5230\u6709\u521d\u503c\u65f6\u624d\u5b9a\u4e49<\/span><br \/>\nstd<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">encryptPassword<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> password<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span>password<span class=\"token punctuation\">.<\/span><span class=\"token function\">length<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&lt;<\/span> MinimumPasswordLength<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">throw<\/span> std<span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">logic_error<\/span><span class=\"token punctuation\">(<\/span><span class=\"token string\">&#034;Password is too short&#034;<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">encrypted<\/span><span class=\"token punctuation\">(<\/span>password<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u76f4\u63a5 copy \u6784\u9020&#xff0c;\u8df3\u8fc7 default \u6784\u9020<\/span><br \/>\n    <span class=\"token function\">encrypt<\/span><span class=\"token punctuation\">(<\/span>encrypted<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> encrypted<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u201c\u5c3d\u53ef\u80fd\u5ef6\u540e&#034;\u4e0d\u53ea\u662f&#034;\u7528\u5230\u524d\u518d\u5b9a\u4e49\u201d&#xff0c;\u800c\u662f**\u201c\u80fd\u7ed9\u521d\u503c\u7684\u65f6\u5019\u518d\u5b9a\u4e49\u201d**\u2014\u2014\u65e0\u610f\u4e49\u7684 default \u6784\u9020&#043;\u8d4b\u503c\u662f\u7eaf\u6d6a\u8d39\u3002<\/p>\n<h3>2. \u5faa\u73af\u91cc\u7684\u53d8\u91cf&#xff1a;\u5b9a\u4e49\u5728\u5185\u8fd8\u662f\u5916&#xff1f;<\/h3>\n<p><span class=\"token comment\">\/\/ \u65b9\u6cd5A&#xff1a;\u5b9a\u4e49\u5728\u5faa\u73af\u5916<\/span><br \/>\nWidget w<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> n<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    w <span class=\"token operator\">&#061;<\/span> \u53d6\u51b3\u4e8ei\u7684\u503c<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ n \u6b21\u8d4b\u503c<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token comment\">\/\/ \u6210\u672c&#xff1a;1 \u6784\u9020 &#043; 1 \u6790\u6784 &#043; n \u8d4b\u503c<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u65b9\u6cd5B&#xff1a;\u5b9a\u4e49\u5728\u5faa\u73af\u5185<\/span><br \/>\n<span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> i <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span> i <span class=\"token operator\">&lt;<\/span> n<span class=\"token punctuation\">;<\/span> <span class=\"token operator\">&#043;&#043;<\/span>i<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    Widget <span class=\"token function\">w<\/span><span class=\"token punctuation\">(<\/span>\u53d6\u51b3\u4e8ei\u7684\u503c<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ n \u6b21\u6784\u9020&#043;\u6790\u6784<\/span><br \/>\n    <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token comment\">\/\/ \u6210\u672c&#xff1a;n \u6784\u9020 &#043; n \u6790\u6784<\/span><\/p>\n<p>Meyers \u7684\u5efa\u8bae\u662f&#xff1a;\u9664\u975e\u4f60\u786e\u8ba4\u8d4b\u503c\u6210\u672c\u4f4e\u4e8e&#034;\u6784\u9020&#043;\u6790\u6784&#034;\u4e14\u8fd9\u6bb5\u4ee3\u7801\u662f\u6027\u80fd\u70ed\u70b9&#xff0c;\u5426\u5219\u9ed8\u8ba4\u7528 B\u3002\u56e0\u4e3a B \u7684\u4f5c\u7528\u57df\u66f4\u5c0f&#xff0c;\u53ef\u8bfb\u6027\u548c\u53ef\u7ef4\u62a4\u6027\u66f4\u597d&#xff0c;\u4e5f\u4e0d\u4f1a\u8ba9\u53d8\u91cf\u540d w \u6cc4\u6f0f\u5230\u5faa\u73af\u5916\u3002<\/p>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;\u5ef6\u540e\u5b9a\u4e49\u4e0e RAII \u7684\u5173\u7cfb<\/h3>\n<p>Q&#xff1a;\u5ef6\u540e\u53d8\u91cf\u5b9a\u4e49\u4f1a\u4e0d\u4f1a\u548c RAII&#xff08;\u8d44\u6e90\u83b7\u53d6\u5373\u521d\u59cb\u5316&#xff09;\u77db\u76fe&#xff1f;RAII \u8981\u6c42\u53d8\u91cf\u5b9a\u4e49\u65f6\u5c31\u83b7\u53d6\u8d44\u6e90\u3002<\/p>\n<p>\u5b8c\u5168\u4e0d\u77db\u76fe&#xff0c;\u53cd\u800c\u662f\u4e00\u81f4\u7684\u3002RAII \u7684\u7cbe\u795e\u662f&#034;\u83b7\u53d6\u8d44\u6e90\u540e\u7acb\u5373\u4ea4\u7ed9\u5bf9\u8c61\u7ba1\u7406&#034;&#xff0c;\u800c\u6761\u6b3e26\u8bf4\u7684\u662f&#034;\u522b\u5728\u771f\u6b63\u9700\u8981\u8d44\u6e90\u4e4b\u524d\u5c31\u83b7\u53d6&#034;\u3002\u4e24\u8005\u7ed3\u5408\u7684\u6b63\u786e\u59ff\u52bf\u662f&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ RAII &#043; \u5ef6\u540e\u5b9a\u4e49&#xff1a;\u9700\u8981\u9501\u7684\u65f6\u5019\u624d\u521b\u5efa Lock \u5bf9\u8c61<\/span><br \/>\n<span class=\"token keyword\">void<\/span> <span class=\"token function\">process<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u524d\u9762\u4e0d\u9700\u8981\u9501\u7684\u51c6\u5907\u5de5\u4f5c<\/span><br \/>\n    <span class=\"token function\">prepareData<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token punctuation\">{<\/span><br \/>\n        Lock <span class=\"token function\">ml<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>mutex<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>        <span class=\"token comment\">\/\/ \u9700\u8981\u65f6\u624d\u83b7\u53d6\u9501<\/span><br \/>\n        <span class=\"token function\">modifySharedState<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span>                           <span class=\"token comment\">\/\/ \u79bb\u5f00\u4f5c\u7528\u57df\u81ea\u52a8\u91ca\u653e<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ \u540e\u9762\u4e0d\u9700\u8981\u9501\u7684\u5de5\u4f5c<\/span><br \/>\n    <span class=\"token function\">writeLog<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5ef6\u540e\u5b9a\u4e49\u672c\u8d28\u4e0a\u662f\u7f29\u5c0f\u53d8\u91cf\u7684\u4f5c\u7528\u57df\u548c\u751f\u547d\u5468\u671f&#xff0c;\u8fd9\u4e0e RAII \u7684&#034;\u7cbe\u786e\u63a7\u5236\u8d44\u6e90\u751f\u547d\u5468\u671f&#034;\u5b8c\u5168\u540c\u9891\u3002\u771f\u6b63\u77db\u76fe\u7684\u662f&#034;\u8fc7\u65e9\u5b9a\u4e49\u4e00\u4e2a RAII \u5bf9\u8c61\u4f46\u957f\u65f6\u95f4\u4e0d\u7528&#034;\u2014\u2014\u90a3\u7b49\u4e8e\u63d0\u524d\u5360\u7740\u8d44\u6e90\u4e0d\u7528&#xff0c;\u53cd\u800c\u662f\u53cd RAII \u7684\u3002<\/p>\n<p>&#x1f4d6; \u5ef6\u540e\u53d8\u91cf\u5b9a\u4e49\u7684\u672c\u8d28\u662f&#034;\u53ea\u4e3a\u771f\u6b63\u7528\u5230\u7684\u5bf9\u8c61\u4ed8\u8d39&#034;&#xff0c;\u4e0e RAII \u7684\u7cbe\u786e\u8d44\u6e90\u7ba1\u7406\u7406\u5ff5\u4e00\u81f4\u3002\u6700\u4f73\u5b9e\u8df5\u662f&#034;\u6709\u610f\u4e49\u7684\u521d\u503c\u51fa\u73b0\u65f6\u624d\u5b9a\u4e49&#034;\u3002<\/p>\n<hr \/>\n<h2>\u4e09\u3001\u6761\u6b3e27&#xff1a;\u5c3d\u91cf\u5c11\u505a\u8f6c\u578b\u52a8\u4f5c<\/h2>\n<p>Minimize casting.<\/p>\n<h3>1. \u56db\u79cd\u65b0\u5f0f\u8f6c\u578b<\/h3>\n<p><span class=\"token generic-function\"><span class=\"token function\">const_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>T<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>expression<span class=\"token punctuation\">)<\/span>      <span class=\"token comment\">\/\/ \u53bb\u9664 const \u6027<\/span><br \/>\n<span class=\"token generic-function\"><span class=\"token function\">dynamic_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>T<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>expression<span class=\"token punctuation\">)<\/span>    <span class=\"token comment\">\/\/ \u5b89\u5168\u5411\u4e0b\u8f6c\u578b&#xff0c;\u6709\u8fd0\u884c\u65f6\u6210\u672c<\/span><br \/>\n<span class=\"token generic-function\"><span class=\"token function\">reinterpret_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>T<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>expression<span class=\"token punctuation\">)<\/span> <span class=\"token comment\">\/\/ \u4f4e\u7ea7\u8f6c\u578b&#xff0c;\u4e0d\u53ef\u79fb\u690d<\/span><br \/>\n<span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>T<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>expression<span class=\"token punctuation\">)<\/span>     <span class=\"token comment\">\/\/ \u5f3a\u8feb\u9690\u5f0f\u8f6c\u6362<\/span><\/p>\n<p>\u65b0\u5f0f\u8f6c\u578b\u6bd4 C \u98ce\u683c (T)expression \u597d\u7684\u539f\u56e0&#xff1a;\u4e00\u662f\u4ee3\u7801\u91cc\u5bb9\u6613 grep \u5b9a\u4f4d&#xff0c;\u4e8c\u662f\u6bcf\u79cd\u8f6c\u578b\u804c\u8d23\u7a84\u5316&#xff0c;\u7f16\u8bd1\u5668\u80fd\u5e2e\u4f60\u8bca\u65ad\u8bef\u7528\u3002<\/p>\n<h3>2. \u8f6c\u578b\u4e0d\u662f&#034;\u544a\u8bc9\u7f16\u8bd1\u5668\u6362\u4e2a\u7c7b\u578b\u770b&#034;\u2014\u2014\u5b83\u771f\u7684\u4f1a\u751f\u6210\u4ee3\u7801<\/h3>\n<p>\u8fd9\u662f\u6700\u8ba9\u6211\u610f\u5916\u7684\u90e8\u5206\u3002\u6211\u4ee5\u524d\u4e5f\u4ee5\u4e3a\u8f6c\u578b\u53ea\u662f\u7f16\u8bd1\u671f\u7684\u7c7b\u578b\u6807\u6ce8&#xff0c;\u4f46\u4e66\u91cc\u4e3e\u4e86\u4e00\u4e2a\u4f8b\u5b50&#xff1a;<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Base<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Derived<\/span> <span class=\"token operator\">:<\/span> <span class=\"token base-clause\"><span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Base<\/span><\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>Derived d<span class=\"token punctuation\">;<\/span><br \/>\nBase<span class=\"token operator\">*<\/span> pb <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&amp;<\/span>d<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ Derived* \u2192 Base*<\/span><\/p>\n<p>\u5728\u591a\u91cd\u7ee7\u627f\u4e0b&#xff0c;Derived* \u548c Base* \u7684\u6307\u9488\u503c\u53ef\u80fd\u4e0d\u540c&#xff01;\u7f16\u8bd1\u5668\u9700\u8981\u5728\u8fd0\u884c\u671f\u7ed9 Derived \u6307\u9488\u52a0\u4e0a\u4e00\u4e2a\u504f\u79fb\u91cf\u624d\u80fd\u5f97\u5230\u6b63\u786e\u7684 Base \u6307\u9488\u3002\u540c\u4e00\u4e2a\u5bf9\u8c61\u53ef\u80fd\u6709\u591a\u4e2a\u5730\u5740\u2014\u2014\u8fd9\u5728 C\u3001Java\u3001C# \u91cc\u90fd\u4e0d\u4f1a\u53d1\u751f&#xff0c;\u4f46 C&#043;&#043; \u4f1a\u3002<\/p>\n<p>\u8fd9\u610f\u5473\u7740\u4efb\u4f55\u57fa\u4e8e&#034;\u6211\u77e5\u9053\u5bf9\u8c61\u5185\u5b58\u5e03\u5c40&#034;\u505a\u7684\u8f6c\u578b\u90fd\u662f\u8106\u5f31\u7684\u3001\u4e0d\u53ef\u79fb\u690d\u7684\u3002<\/p>\n<h3>3. \u4e00\u4e2a\u9690\u853d\u7684 bug&#xff1a;\u5728\u6d3e\u751f\u7c7b\u51fd\u6570\u91cc\u8f6c\u578b *this<\/h3>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Window<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token keyword\">virtual<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">onResize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">SpecialWindow<\/span> <span class=\"token operator\">:<\/span> <span class=\"token base-clause\"><span class=\"token keyword\">public<\/span> <span class=\"token class-name\">Window<\/span><\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token keyword\">virtual<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">onResize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token comment\">\/\/ \u274c \u9519\u8bef&#xff01;\u8fd9\u4f1a\u521b\u5efa *this \u7684 Base \u6210\u5206\u526f\u672c&#xff0c;\u5728\u526f\u672c\u4e0a\u8c03\u7528<\/span><br \/>\n        <span class=\"token generic-function\"><span class=\"token function\">static_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>Window<span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">onResize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token comment\">\/\/ SpecialWindow \u4e13\u5c5e\u884c\u4e3a&#8230;<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>static_cast&lt;Window&gt;(*this) \u4e0d\u662f&#034;\u628a\u81ea\u5df1\u5f53 Window \u770b&#034;&#xff0c;\u800c\u662f\u62f7\u8d1d\u6784\u9020\u4e86\u4e00\u4e2a\u4e34\u65f6 Window \u5bf9\u8c61&#xff0c;\u7136\u540e\u5728\u8fd9\u4e2a\u526f\u672c\u4e0a\u8c03\u7528 onResize\u3002\u5982\u679c\u57fa\u7c7b\u7248\u672c\u4fee\u6539\u4e86\u5bf9\u8c61\u72b6\u6001&#xff0c;\u6539\u7684\u662f\u526f\u672c&#xff0c;\u539f\u5bf9\u8c61\u7684\u57fa\u7c7b\u90e8\u5206\u6ca1\u88ab\u6539\u5230\u2014\u2014\u5bf9\u8c61\u8fdb\u5165&#034;\u57fa\u7c7b\u6ca1\u6539\u3001\u6d3e\u751f\u7c7b\u6539\u4e86&#034;\u7684\u4f24\u6b8b\u72b6\u6001\u3002<\/p>\n<p>\u6b63\u786e\u5199\u6cd5\u7b80\u5355\u76f4\u63a5&#xff1a;<\/p>\n<p><span class=\"token keyword\">virtual<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">onResize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token class-name\">Window<\/span><span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">onResize<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5728\u5f53\u524d\u5bf9\u8c61\u4e0a\u8c03\u7528\u57fa\u7c7b\u7248\u672c<\/span><br \/>\n    <span class=\"token comment\">\/\/ SpecialWindow \u4e13\u5c5e\u884c\u4e3a&#8230;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>4. dynamic_cast \u5f88\u6162&#xff0c;\u8981\u907f\u514d\u8fde\u4e32\u4f7f\u7528<\/h3>\n<p>dynamic_cast \u7684\u5f88\u591a\u5b9e\u73b0\u57fa\u4e8e\u7c7b\u540d\u5b57\u7b26\u4e32\u6bd4\u8f83&#xff0c;\u5728\u56db\u5c42\u6df1\u7684\u7ee7\u627f\u4f53\u7cfb\u91cc\u53ef\u80fd\u8981\u505a\u56db\u6b21 strcmp\u3002\u8fde\u4e32 dynamic_cast \u66f4\u662f\u707e\u96be&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u7cdf\u7cd5&#xff1a;\u8fde\u4e32 dynamic_cast<\/span><br \/>\n<span class=\"token keyword\">for<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span><span class=\"token operator\">&amp;<\/span> pw <span class=\"token operator\">:<\/span> winPtrs<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span> psw1 <span class=\"token operator\">&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">dynamic_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>SpecialWindow1<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>pw<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span> psw2 <span class=\"token operator\">&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">dynamic_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>SpecialWindow2<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>pw<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">else<\/span> <span class=\"token keyword\">if<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token keyword\">auto<\/span> psw3 <span class=\"token operator\">&#061;<\/span> <span class=\"token generic-function\"><span class=\"token function\">dynamic_cast<\/span><span class=\"token generic class-name\"><span class=\"token operator\">&lt;<\/span>SpecialWindow3<span class=\"token operator\">*<\/span><span class=\"token operator\">&gt;<\/span><\/span><\/span><span class=\"token punctuation\">(<\/span>pw<span class=\"token punctuation\">.<\/span><span class=\"token function\">get<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4e24\u79cd\u66ff\u4ee3\u65b9\u6848&#xff1a;<\/p>\n<li>\u7c7b\u578b\u5b89\u5168\u5bb9\u5668&#xff1a;\u7528 vector&lt;shared_ptr&lt;SpecialWindow&gt;&gt; \u76f4\u63a5\u5b58\u6d3e\u751f\u7c7b\u6307\u9488<\/li>\n<li>virtual \u51fd\u6570\u4e0a\u63d0&#xff1a;\u5728\u57fa\u7c7b\u91cc\u52a0 virtual \u51fd\u6570&#xff0c;\u7528\u591a\u6001\u66ff\u4ee3\u8f6c\u578b<\/li>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;\u4e3a\u4ec0\u4e48 C&#043;&#043; \u7684\u5bf9\u8c61\u53ef\u4ee5\u6709\u591a\u4e2a\u5730\u5740<\/h3>\n<p>Q&#xff1a;C\u3001Java\u3001C# \u91cc\u4e00\u4e2a\u5bf9\u8c61\u53ea\u6709\u4e00\u4e2a\u5730\u5740&#xff0c;\u4e3a\u4ec0\u4e48 C&#043;&#043; \u5141\u8bb8\u591a\u4e2a\u5730\u5740&#xff1f;<\/p>\n<p>\u8fd9\u4e0e C&#043;&#043; \u7684\u5185\u5b58\u5e03\u5c40\u81ea\u7531\u5ea6\u76f4\u63a5\u76f8\u5173\u3002C&#043;&#043; \u6807\u51c6\u4e0d\u89c4\u5b9a\u5bf9\u8c61\u7684\u5185\u5b58\u5e03\u5c40&#xff0c;\u7f16\u8bd1\u5668\u53ef\u4ee5\u81ea\u7531\u5b89\u6392\u3002\u5728\u591a\u91cd\u7ee7\u627f\u4e0b&#xff0c;\u4e00\u4e2a\u6d3e\u751f\u7c7b\u5bf9\u8c61\u5305\u542b\u591a\u4e2a\u57fa\u7c7b\u5b50\u5bf9\u8c61&#xff0c;\u6bcf\u4e2a\u5b50\u5bf9\u8c61\u5728\u5185\u5b58\u4e2d\u6709\u4e0d\u540c\u7684\u8d77\u59cb\u4f4d\u7f6e&#xff1a;<\/p>\n<p>Derived \u5bf9\u8c61\u5185\u5b58\u5e03\u5c40&#xff08;\u591a\u91cd\u7ee7\u627f&#xff09;:<br \/>\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510<br \/>\n\u2502   Base1 \u5b50\u5bf9\u8c61   \u2502 \u2190 Base1* \u6307\u5411\u8fd9\u91cc<br \/>\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524<br \/>\n\u2502   Base2 \u5b50\u5bf9\u8c61   \u2502 \u2190 Base2* \u6307\u5411\u8fd9\u91cc&#xff08;\u504f\u79fb\u91cf &#061; sizeof(Base1)&#xff09;<br \/>\n\u251c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2524<br \/>\n\u2502 Derived \u72ec\u6709\u6210\u5458 \u2502 \u2190 Derived* \u901a\u5e38\u6307\u5411\u5f00\u5934<br \/>\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/p>\n<p>\u5f53\u4f60\u628a Derived* \u8f6c\u6210 Base2*&#xff0c;\u7f16\u8bd1\u5668\u5fc5\u987b\u52a0\u4e0a\u504f\u79fb\u91cf\u3002\u8fd9\u4e2a\u504f\u79fb\u91cf\u5728\u5355\u7ee7\u627f\u4e0b\u901a\u5e38\u662f0&#xff08;\u6240\u4ee5\u4f60\u611f\u89c9\u4e0d\u5230&#xff09;&#xff0c;\u5728\u591a\u7ee7\u627f\u4e0b\u51e0\u4e4e\u4e00\u5b9a\u975e\u96f6\u3002<\/p>\n<p>Java \u548c C# \u4e4b\u6240\u4ee5\u6ca1\u6709\u8fd9\u4e2a\u95ee\u9898&#xff0c;\u662f\u56e0\u4e3a\u5b83\u4eec\u7684\u8fd0\u884c\u65f6\u7edf\u4e00\u7528&#034;\u5bf9\u8c61\u5f15\u7528&#043;\u7c7b\u578b\u6807\u7b7e&#034;\u7684\u6a21\u578b&#xff0c;\u5f15\u7528\u672c\u8eab\u662f\u95f4\u63a5\u53e5\u67c4&#xff0c;\u4e0d\u76f4\u63a5\u6307\u5411\u5185\u5b58\u4e2d\u7684\u5b50\u5bf9\u8c61\u4f4d\u7f6e\u3002\u4ee3\u4ef7\u662f\u6bcf\u6b21\u8bbf\u95ee\u90fd\u591a\u4e00\u5c42\u95f4\u63a5\u8df3\u8f6c\u2014\u2014C&#043;&#043; \u9009\u62e9\u628a\u8fd9\u4e2a\u6210\u672c\u66b4\u9732\u7ed9\u4f60&#xff0c;\u8ba9\u4f60\u80fd\u63a7\u5236&#xff1b;Java\/C# \u9009\u62e9\u5e2e\u4f60\u85cf\u8d77\u6765&#xff0c;\u4f46\u4f60\u6c38\u8fdc\u8981\u4ed8\u95f4\u63a5\u8df3\u8f6c\u7684\u7a0e\u3002<\/p>\n<p>&#x1f4d6; \u8f6c\u578b\u4e0d\u53ea\u662f\u7c7b\u578b\u6807\u6ce8&#xff0c;\u5b83\u53ef\u80fd\u751f\u6210\u8fd0\u884c\u65f6\u4ee3\u7801\u3001\u521b\u5efa\u4e34\u65f6\u5bf9\u8c61\u3001\u6539\u53d8\u6307\u9488\u503c\u3002\u4f18\u79c0\u7684 C&#043;&#043; \u4ee3\u7801\u8f6c\u578b\u5f88\u5c11&#xff1b;\u5982\u679c\u8bbe\u8ba1\u9700\u8981\u9891\u7e41\u8f6c\u578b&#xff0c;\u5c24\u5176\u662f\u8fde\u4e32 dynamic_cast&#xff0c;\u901a\u5e38\u8bf4\u660e\u7ee7\u627f\u4f53\u7cfb\u672c\u8eab\u9700\u8981\u91cd\u6784\u3002<\/p>\n<hr \/>\n<h2>\u56db\u3001\u6761\u6b3e28&#xff1a;\u907f\u514d\u8fd4\u56de handles \u6307\u5411\u5bf9\u8c61\u5185\u90e8\u6210\u5206<\/h2>\n<p>Avoid returning \u201chandles\u201d to object internals.<\/p>\n<h3>1. const \u6210\u5458\u51fd\u6570\u5374\u80fd\u4fee\u6539\u5bf9\u8c61<\/h3>\n<p>\u4e66\u91cc\u7ed9\u4e86\u4e00\u4e2a\u77e9\u5f62\u7c7b\u7684\u4f8b\u5b50&#xff1a;<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Point<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">Point<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> x<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> y<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">void<\/span> <span class=\"token function\">setX<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> newVal<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">void<\/span> <span class=\"token function\">setY<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span> newVal<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">RectData<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    Point ulhc<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5de6\u4e0a\u89d2<\/span><br \/>\n    Point lrhc<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u53f3\u4e0b\u89d2<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Rectangle<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token comment\">\/\/ \u274c const \u51fd\u6570\u5374\u8fd4\u56de\u975e const \u5f15\u7528&#xff01;<\/span><br \/>\n    Point<span class=\"token operator\">&amp;<\/span> <span class=\"token function\">upperLeft<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> pData<span class=\"token operator\">-&gt;<\/span>ulhc<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n    Point<span class=\"token operator\">&amp;<\/span> <span class=\"token function\">lowerRight<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> pData<span class=\"token operator\">-&gt;<\/span>lrhc<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>tr1<span class=\"token double-colon punctuation\">::<\/span>shared_ptr<span class=\"token operator\">&lt;<\/span>RectData<span class=\"token operator\">&gt;<\/span> pData<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u4e24\u4e2a\u51fd\u6570\u88ab\u58f0\u660e\u4e3a const&#xff0c;\u4f46\u5b83\u4eec\u8fd4\u56de\u7684\u5f15\u7528\u5141\u8bb8\u8c03\u7528\u8005\u4fee\u6539\u5185\u90e8\u6570\u636e&#xff1a;<\/p>\n<p><span class=\"token keyword\">const<\/span> Rectangle <span class=\"token function\">rec<\/span><span class=\"token punctuation\">(<\/span>coord1<span class=\"token punctuation\">,<\/span> coord2<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ const \u77e9\u5f62<\/span><br \/>\nrec<span class=\"token punctuation\">.<\/span><span class=\"token function\">upperLeft<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">setX<\/span><span class=\"token punctuation\">(<\/span><span class=\"token number\">50<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ rec \u5c45\u7136\u88ab\u6539\u4e86&#xff01;<\/span><\/p>\n<p>\u4e24\u4e2a\u6559\u8bad&#xff1a;<\/p>\n<li>\u6210\u5458\u53d8\u91cf\u7684\u5c01\u88c5\u6027\u6700\u591a\u7b49\u4e8e\u8fd4\u56de\u5176\u5f15\u7528\u7684\u51fd\u6570\u7684\u8bbf\u95ee\u7ea7\u522b\u2014\u2014\u867d\u7136 ulhc \u662f private&#xff0c;\u4f46 public \u51fd\u6570\u4f20\u51fa\u4e86\u5b83\u7684\u5f15\u7528&#xff0c;\u5b83\u5b9e\u9645\u4e0a\u5c31\u662f public<\/li>\n<li>const \u6210\u5458\u51fd\u6570\u4f20\u51fa\u5f15\u7528&#xff0c;\u5f15\u7528\u6240\u6307\u6570\u636e\u4e0e\u5bf9\u8c61\u81ea\u8eab\u5173\u8054\u4e14\u5b58\u50a8\u5728\u5bf9\u8c61\u5916&#xff0c;\u8c03\u7528\u8005\u5c31\u80fd\u4fee\u6539\u90a3\u7b14\u6570\u636e<\/li>\n<h3>2. \u52a0 const \u53ef\u4ee5\u89e3\u51b3\u5c01\u88c5\u95ee\u9898<\/h3>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Rectangle<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token keyword\">const<\/span> Point<span class=\"token operator\">&amp;<\/span> <span class=\"token function\">upperLeft<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> pData<span class=\"token operator\">-&gt;<\/span>ulhc<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n    <span class=\"token keyword\">const<\/span> Point<span class=\"token operator\">&amp;<\/span> <span class=\"token function\">lowerRight<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token keyword\">return<\/span> pData<span class=\"token operator\">-&gt;<\/span>lrhc<span class=\"token punctuation\">;<\/span> <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u73b0\u5728\u5ba2\u6237\u53ea\u80fd\u8bfb\u4e0d\u80fd\u5199\u3002\u4f46\u8fd8\u6709\u66f4\u9690\u853d\u7684\u5371\u9669\u2014\u2014<\/p>\n<h3>3. \u60ac\u7a7a handle&#xff08;dangling handles&#xff09;<\/h3>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">GUIObject<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u8fd4\u56de\u4e00\u4e2a by-value \u7684\u4e34\u65f6\u77e9\u5f62<\/span><br \/>\n<span class=\"token keyword\">const<\/span> Rectangle <span class=\"token function\">boundingBox<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> GUIObject<span class=\"token operator\">&amp;<\/span> obj<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>GUIObject<span class=\"token operator\">*<\/span> pgo<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">\/\/ \u26a0\ufe0f pUpperLeft \u6307\u5411\u4e34\u65f6\u5bf9\u8c61\u7684\u5185\u90e8\u6210\u5206<\/span><br \/>\n<span class=\"token keyword\">const<\/span> Point<span class=\"token operator\">*<\/span> pUpperLeft <span class=\"token operator\">&#061;<\/span> <span class=\"token operator\">&amp;<\/span><span class=\"token punctuation\">(<\/span><span class=\"token function\">boundingBox<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span>pgo<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">upperLeft<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u8fd9\u884c\u8bed\u53e5\u7ed3\u675f\u540e&#xff0c;boundingBox \u8fd4\u56de\u7684\u4e34\u65f6 Rectangle \u88ab\u9500\u6bc1&#xff0c;\u5b83\u5185\u90e8\u7684 Point \u4e5f\u8ddf\u7740\u9500\u6bc1&#xff0c;pUpperLeft \u53d8\u6210\u60ac\u7a7a\u6307\u9488\u3002<\/p>\n<p>\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48&#034;\u8fd4\u56de handle \u6307\u5411\u5bf9\u8c61\u5185\u90e8&#034;\u603b\u662f\u5371\u9669\u7684\u2014\u2014handle \u53ef\u80fd\u6bd4\u5b83\u6240\u6307\u7684\u5bf9\u8c61\u66f4\u957f\u5bff\u3002\u4e0d\u8bba handle \u662f\u6307\u9488\u3001\u5f15\u7528\u8fd8\u662f\u8fed\u4ee3\u5668&#xff0c;\u4e0d\u8bba\u5b83\u662f\u4e0d\u662f const&#xff0c;\u4e0d\u8bba\u6210\u5458\u51fd\u6570\u662f\u4e0d\u662f const&#xff0c;\u90fd\u6709\u8fd9\u4e2a\u98ce\u9669\u3002<\/p>\n<p>\u5f53\u7136\u4e5f\u6709\u4f8b\u5916&#xff1a;operator[] \u5c31\u662f\u8fd4\u56de\u5f15\u7528\u6307\u5411\u5bb9\u5668\u5185\u90e8\u6570\u636e&#xff0c;\u8fd9\u662f\u6709\u610f\u7684\u8bbe\u8ba1&#xff0c;\u4f46\u5b83\u662f\u4f8b\u5916\u800c\u975e\u5e38\u6001\u3002<\/p>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;const \u5f15\u7528\u8fd4\u56de\u503c\u4e0e\u4e34\u65f6\u5bf9\u8c61\u751f\u547d\u5468\u671f<\/h3>\n<p>Q&#xff1a;C&#043;&#043; \u4e0d\u662f\u6709&#034;const \u5f15\u7528\u7ed1\u5b9a\u4e34\u65f6\u5bf9\u8c61\u4f1a\u5ef6\u957f\u4e34\u65f6\u5bf9\u8c61\u751f\u547d\u5468\u671f&#034;\u7684\u89c4\u5219\u5417&#xff1f;\u4e3a\u4ec0\u4e48\u8fd9\u91cc\u8fd8\u662f\u60ac\u7a7a\u4e86&#xff1f;<\/p>\n<p>\u8fd9\u662f\u4e00\u4e2a\u975e\u5e38\u597d\u7684\u95ee\u9898&#xff0c;\u4e5f\u662f C&#043;&#043; \u4e2d\u6700\u5bb9\u6613\u8e29\u7684\u5751\u4e4b\u4e00\u3002\u751f\u547d\u5468\u671f\u5ef6\u957f\u89c4\u5219\u6709\u4e25\u683c\u7684\u9002\u7528\u6761\u4ef6&#xff1a;<\/p>\n<p><span class=\"token comment\">\/\/ \u2705 \u751f\u547d\u5468\u671f\u5ef6\u957f&#xff1a;const \u5f15\u7528\u76f4\u63a5\u7ed1\u5b9a\u5230\u4e34\u65f6\u5bf9\u8c61<\/span><br \/>\n<span class=\"token keyword\">const<\/span> Rectangle<span class=\"token operator\">&amp;<\/span> rect <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">boundingBox<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span>pgo<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u4e34\u65f6\u5bf9\u8c61\u5b58\u6d3b\u5230 rect \u79bb\u5f00\u4f5c\u7528\u57df<\/span><\/p>\n<p><span class=\"token comment\">\/\/ \u274c \u6ca1\u6709\u5ef6\u957f&#xff1a;const \u5f15\u7528\u7ed1\u5b9a\u5230\u7684\u662f\u4e34\u65f6\u5bf9\u8c61\u7684\u5185\u90e8\u6210\u5458<\/span><br \/>\n<span class=\"token keyword\">const<\/span> Point<span class=\"token operator\">&amp;<\/span> pt <span class=\"token operator\">&#061;<\/span> <span class=\"token function\">boundingBox<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span>pgo<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">.<\/span><span class=\"token function\">upperLeft<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token comment\">\/\/ boundingBox \u8fd4\u56de\u7684\u4e34\u65f6 Rectangle \u5728\u8bed\u53e5\u7ed3\u675f\u65f6\u9500\u6bc1<\/span><br \/>\n<span class=\"token comment\">\/\/ pt \u5f15\u7528\u7684\u662f\u90a3\u4e2a\u4e34\u65f6\u5bf9\u8c61\u7684\u6210\u5458&#xff0c;\u6210\u5458\u968f\u5bbf\u4e3b\u4e00\u8d77\u9500\u6bc1<\/span><\/p>\n<p>\u5173\u952e\u533a\u522b&#xff1a;\u751f\u547d\u5468\u671f\u5ef6\u957f\u53ea\u4f5c\u7528\u4e8e\u76f4\u63a5\u7ed1\u5b9a\u7684\u4e34\u65f6\u5bf9\u8c61\u672c\u8eab&#xff0c;\u4e0d\u4f1a\u9012\u5f52\u5ef6\u957f&#034;\u4e34\u65f6\u5bf9\u8c61\u5185\u90e8\u6210\u5206&#034;\u7684\u751f\u547d\u5468\u671f\u3002upperLeft() \u8fd4\u56de\u7684\u5f15\u7528\u6307\u5411\u7684\u662f Rectangle \u7684\u6210\u5458&#xff0c;\u4e0d\u662f\u4e34\u65f6\u5bf9\u8c61\u672c\u8eab&#xff0c;\u6240\u4ee5\u4e0d\u89e6\u53d1\u5ef6\u957f\u3002<\/p>\n<p>C&#043;&#043; \u6807\u51c6 [class.temporary] \u660e\u786e\u89c4\u5b9a&#xff1a;\u4e34\u65f6\u5bf9\u8c61\u7684\u751f\u547d\u5468\u671f\u4e0d\u4f1a\u56e0\u4e3a&#034;\u6307\u5411\u5176\u6210\u5458\u7684\u5f15\u7528&#034;\u800c\u5ef6\u957f\u3002\u8fd9\u662f\u7f16\u8bd1\u5668\u5b9e\u73b0\u53ef\u884c\u6027\u7684\u6743\u8861\u2014\u2014\u8981\u8ffd\u8e2a\u6240\u6709&#034;\u4ece\u4e34\u65f6\u5bf9\u8c61\u6d3e\u751f\u51fa\u7684\u5f15\u7528&#034;\u5728\u5b9e\u8df5\u4e2d\u6781\u5176\u56f0\u96be\u4e14\u6210\u672c\u9ad8\u6602\u3002<\/p>\n<p>&#x1f4d6; \u8fd4\u56de\u5185\u90e8 handle \u540c\u65f6\u5a01\u80c1\u5c01\u88c5\u6027\u548c\u751f\u547d\u5468\u671f\u5b89\u5168\u3002const \u5f15\u7528\u8fd4\u56de\u503c\u65e0\u6cd5\u89e3\u51b3\u60ac\u7a7a\u95ee\u9898&#xff0c;\u56e0\u4e3a\u751f\u547d\u5468\u671f\u5ef6\u957f\u4e0d\u9012\u5f52\u5230\u5185\u90e8\u6210\u5458\u3002\u5982\u679c\u5fc5\u987b\u8fd4\u56de&#xff0c;\u786e\u4fdd\u8fd4\u56de\u7684\u662f\u503c\u6216\u957f\u751f\u547d\u5468\u671f\u5bf9\u8c61\u7684 handle\u3002<\/p>\n<hr \/>\n<h2>\u4e94\u3001\u6761\u6b3e29&#xff1a;\u4e3a&#034;\u5f02\u5e38\u5b89\u5168&#034;\u800c\u52aa\u529b\u662f\u503c\u5f97\u7684<\/h2>\n<p>Strive for exception-safe code.<\/p>\n<h3>1. \u5f02\u5e38\u5b89\u5168\u7684\u4e24\u4e2a\u6761\u4ef6<\/h3>\n<p>\u5f53\u5f02\u5e38\u88ab\u629b\u51fa\u65f6&#xff0c;\u5f02\u5e38\u5b89\u5168\u51fd\u6570\u8981\u4fdd\u8bc1&#xff1a;<\/p>\n<li>\u4e0d\u6cc4\u6f0f\u8d44\u6e90<\/li>\n<li>\u4e0d\u5141\u8bb8\u6570\u636e\u8d25\u574f<\/li>\n<p>\u770b\u4e00\u4e2a\u53cd\u9762\u6559\u6750&#xff1a;<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">PrettyMenu<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    Mutex mutex<span class=\"token punctuation\">;<\/span><br \/>\n    Image<span class=\"token operator\">*<\/span> bgImage<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> imageChanges<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">void<\/span> <span class=\"token function\">changeBackground<\/span><span class=\"token punctuation\">(<\/span>std<span class=\"token double-colon punctuation\">::<\/span>istream<span class=\"token operator\">&amp;<\/span> imgSrc<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token function\">lock<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>mutex<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token keyword\">delete<\/span> bgImage<span class=\"token punctuation\">;<\/span><br \/>\n        <span class=\"token operator\">&#043;&#043;<\/span>imageChanges<span class=\"token punctuation\">;<\/span><br \/>\n        bgImage <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token function\">Image<\/span><span class=\"token punctuation\">(<\/span>imgSrc<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u5982\u679c\u8fd9\u91cc\u629b\u5f02\u5e38&#8230;<\/span><br \/>\n        <span class=\"token function\">unlock<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>mutex<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>               <span class=\"token comment\">\/\/ &#8230;unlock \u6c38\u8fdc\u4e0d\u4f1a\u6267\u884c \u2192 \u9501\u6cc4\u6f0f<\/span><br \/>\n                                      <span class=\"token comment\">\/\/ bgImage \u6307\u5411\u5df2\u5220\u9664\u5bf9\u8c61 \u2192 \u6570\u636e\u8d25\u574f<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<h3>2. \u7528\u5bf9\u8c61\u7ba1\u7406\u8d44\u6e90\u89e3\u51b3\u6cc4\u6f0f<\/h3>\n<p>\u6761\u6b3e13-14 \u7684 RAII \u76f4\u63a5\u89e3\u51b3\u7b2c\u4e00\u4e2a\u95ee\u9898&#xff1a;<\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token class-name\">PrettyMenu<\/span><span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">changeBackground<\/span><span class=\"token punctuation\">(<\/span>std<span class=\"token double-colon punctuation\">::<\/span>istream<span class=\"token operator\">&amp;<\/span> imgSrc<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    Lock <span class=\"token function\">m1<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>mutex<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>                  <span class=\"token comment\">\/\/ \u6784\u9020\u65f6\u52a0\u9501&#xff0c;\u6790\u6784\u65f6\u89e3\u9501<\/span><br \/>\n    <span class=\"token keyword\">delete<\/span> bgImage<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token operator\">&#043;&#043;<\/span>imageChanges<span class=\"token punctuation\">;<\/span><br \/>\n    bgImage <span class=\"token operator\">&#061;<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token function\">Image<\/span><span class=\"token punctuation\">(<\/span>imgSrc<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u4ee3\u7801\u53d8\u77ed\u4e86&#xff0c;\u4e5f\u4e0d\u4f1a\u6f0f unlock\u3002\u4f46\u6570\u636e\u8d25\u574f\u8fd8\u6ca1\u89e3\u51b3\u2014\u2014\u5982\u679c new Image \u629b\u5f02\u5e38&#xff0c;bgImage \u5df2\u88ab delete&#xff0c;imageChanges \u5df2\u88ab\u9012\u589e\u3002<\/p>\n<h3>3. \u4e09\u4e2a\u5f02\u5e38\u5b89\u5168\u4fdd\u8bc1<\/h3>\n<table>\n<tr>\u4fdd\u8bc1\u7b49\u7ea7\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>\u57fa\u672c\u627f\u8bfa<\/td>\n<td>\u5f02\u5e38\u629b\u51fa\u540e&#xff0c;\u7a0b\u5e8f\u5904\u4e8e\u6709\u6548\u72b6\u6001&#xff0c;\u6240\u6709\u5bf9\u8c61\u5185\u90e8\u4e00\u81f4&#xff0c;\u4f46\u5177\u4f53\u72b6\u6001\u4e0d\u53ef\u9884\u77e5<\/td>\n<\/tr>\n<tr>\n<td>\u5f3a\u70c8\u4fdd\u8bc1<\/td>\n<td>\u5f02\u5e38\u629b\u51fa\u540e&#xff0c;\u7a0b\u5e8f\u72b6\u6001\u5b8c\u5168\u56de\u6eda\u5230\u8c03\u7528\u524d\u2014\u2014\u8981\u4e48\u6210\u529f&#xff0c;\u8981\u4e48\u539f\u72b6<\/td>\n<\/tr>\n<tr>\n<td>\u4e0d\u629b\u5f02\u5e38&#xff08;nothrow&#xff09;<\/td>\n<td>\u627f\u8bfa\u7edd\u4e0d\u629b\u51fa\u5f02\u5e38&#xff08;\u5185\u7f6e\u7c7b\u578b\u64cd\u4f5c\u5929\u7136 nothrow&#xff09;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>4. copy-and-swap \u5b9e\u73b0\u5f3a\u70c8\u4fdd\u8bc1<\/h3>\n<p><span class=\"token keyword\">struct<\/span> <span class=\"token class-name\">PMImpl<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>tr1<span class=\"token double-colon punctuation\">::<\/span>shared_ptr<span class=\"token operator\">&lt;<\/span>Image<span class=\"token operator\">&gt;<\/span> bgImage<span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">int<\/span> imageChanges<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">PrettyMenu<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    Mutex mutex<span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>tr1<span class=\"token double-colon punctuation\">::<\/span>shared_ptr<span class=\"token operator\">&lt;<\/span>PMImpl<span class=\"token operator\">&gt;<\/span> pImpl<span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token keyword\">void<\/span> <span class=\"token function\">changeBackground<\/span><span class=\"token punctuation\">(<\/span>std<span class=\"token double-colon punctuation\">::<\/span>istream<span class=\"token operator\">&amp;<\/span> imgSrc<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n        <span class=\"token keyword\">using<\/span> std<span class=\"token double-colon punctuation\">::<\/span>swap<span class=\"token punctuation\">;<\/span><br \/>\n        Lock <span class=\"token function\">m1<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">&amp;<\/span>mutex<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token comment\">\/\/ \u5148\u5728\u526f\u672c\u4e0a\u6539<\/span><br \/>\n        std<span class=\"token double-colon punctuation\">::<\/span>tr1<span class=\"token double-colon punctuation\">::<\/span>shared_ptr<span class=\"token operator\">&lt;<\/span>PMImpl<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">pNew<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">new<\/span> <span class=\"token function\">PMImpl<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span>pImpl<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n        pNew<span class=\"token operator\">-&gt;<\/span>bgImage<span class=\"token punctuation\">.<\/span><span class=\"token function\">reset<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">new<\/span> <span class=\"token function\">Image<\/span><span class=\"token punctuation\">(<\/span>imgSrc<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u4fee\u6539\u526f\u672c<\/span><br \/>\n        <span class=\"token operator\">&#043;&#043;<\/span>pNew<span class=\"token operator\">-&gt;<\/span>imageChanges<span class=\"token punctuation\">;<\/span><\/p>\n<p>        <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span>pImpl<span class=\"token punctuation\">,<\/span> pNew<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u4e00\u6b21\u6027\u63d0\u4ea4&#xff0c;no-throw swap<\/span><br \/>\n    <span class=\"token punctuation\">}<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u6838\u5fc3\u601d\u8def&#xff1a;\u5728\u526f\u672c\u4e0a\u505a\u6240\u6709\u53ef\u80fd\u629b\u5f02\u5e38\u7684\u4fee\u6539&#xff0c;\u5168\u90e8\u6210\u529f\u540e\u518d\u7528 no-throw swap \u4e00\u6b21\u6027\u63d0\u4ea4\u3002\u5982\u679c\u4e2d\u9014\u4efb\u4f55\u4e00\u6b65\u629b\u5f02\u5e38&#xff0c;\u539f\u5bf9\u8c61\u4fdd\u6301\u4e0d\u53d8\u3002<\/p>\n<p>\u4f46\u5f3a\u70c8\u4fdd\u8bc1\u4e0d\u662f\u4e07\u80fd\u7684&#xff1a;<\/p>\n<ul>\n<li>\u5982\u679c\u51fd\u6570\u6709\u8fde\u5e26\u5f71\u54cd&#xff08;side effects&#xff09;&#xff0c;\u6bd4\u5982\u6539\u4e86\u6570\u636e\u5e93&#xff0c;\u5f02\u5e38\u540e\u6ca1\u6cd5\u56de\u6eda\u6570\u636e\u5e93<\/li>\n<li>copy-and-swap \u7684\u65f6\u95f4\u548c\u7a7a\u95f4\u6210\u672c\u53ef\u80fd\u4e0d\u53ef\u63a5\u53d7<\/li>\n<li>\u51fd\u6570\u7684\u5f02\u5e38\u5b89\u5168\u4fdd\u8bc1\u6700\u9ad8\u53ea\u7b49\u4e8e\u5b83\u8c03\u7528\u7684\u6700\u5f31\u51fd\u6570\u7684\u4fdd\u8bc1\u2014\u2014\u6728\u6876\u6548\u5e94<\/li>\n<\/ul>\n<h3>5. \u5f02\u5e38\u5b89\u5168\u662f\u5168\u6709\u6216\u5168\u65e0\u7684<\/h3>\n<p>Meyers \u7528\u4e86\u4e00\u4e2a\u7cbe\u5999\u7684\u6bd4\u55bb&#xff1a;\u5f02\u5e38\u5b89\u5168\u5c31\u50cf\u6000\u5b55\u2014\u2014\u8981\u4e48\u6000\u4e86\u8981\u4e48\u6ca1\u6000&#xff0c;\u6ca1\u6709&#034;\u90e8\u5206\u6000\u5b55&#034;\u3002\u53ea\u8981\u7cfb\u7edf\u4e2d\u6709\u4e00\u4e2a\u51fd\u6570\u4e0d\u5177\u5907\u5f02\u5e38\u5b89\u5168\u6027&#xff0c;\u6574\u4e2a\u7cfb\u7edf\u5c31\u4e0d\u662f\u5f02\u5e38\u5b89\u5168\u7684&#xff0c;\u56e0\u4e3a\u8c03\u7528\u90a3\u4e2a\u51fd\u6570\u53ef\u80fd\u6cc4\u6f0f\u8d44\u6e90\u6216\u8d25\u574f\u6570\u636e\u3002<\/p>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;copy-and-swap \u4e0e C&#043;&#043;11 \u79fb\u52a8\u8bed\u4e49\u7684\u5173\u7cfb<\/h3>\n<p>Q&#xff1a;C&#043;&#043;11 \u7684\u79fb\u52a8\u8bed\u4e49\u662f\u5426\u8ba9 copy-and-swap \u8fc7\u65f6\u4e86&#xff1f;<\/p>\n<p>\u6ca1\u6709\u8fc7\u65f6&#xff0c;\u4f46\u5e94\u7528\u65b9\u5f0f\u6709\u6240\u6f14\u53d8\u3002copy-and-swap \u5728 C&#043;&#043;11 \u4e4b\u540e\u5206\u5316\u4e3a\u4e24\u79cd\u7528\u6cd5&#xff1a;<\/p>\n<table>\n<tr>\u573a\u666fC&#043;&#043;03 \u505a\u6cd5C&#043;&#043;11&#043; \u505a\u6cd5<\/tr>\n<tbody>\n<tr>\n<td>operator&#061; \u5b9e\u73b0<\/td>\n<td>copy-and-swap&#xff08;\u62f7\u8d1d\u6784\u9020&#043;swap&#xff09;<\/td>\n<td>copy-and-swap \u6216 move-and-swap<\/td>\n<\/tr>\n<tr>\n<td>\u591a\u6b65\u4fee\u6539\u63d0\u4ea4<\/td>\n<td>\u6df1\u62f7\u8d1d\u6574\u4e2a\u5bf9\u8c61\u518d swap<\/td>\n<td>\u53ef\u4ee5 move \u4e34\u65f6\u5bf9\u8c61\u8fdb\u53bb<\/td>\n<\/tr>\n<tr>\n<td>\u6027\u80fd<\/td>\n<td>\u6df1\u62f7\u8d1d\u6210\u672c\u9ad8<\/td>\n<td>move \u53ea\u4ea4\u6362\u6307\u9488&#xff0c;\u6210\u672c\u63a5\u8fd1 0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>C&#043;&#043;11 \u4e4b\u540e&#xff0c;operator&#061; \u7684 copy-and-swap \u5199\u6cd5\u53d8\u5f97\u66f4\u4f18\u96c5&#xff1a;<\/p>\n<p>Widget<span class=\"token operator\">&amp;<\/span> <span class=\"token keyword\">operator<\/span><span class=\"token operator\">&#061;<\/span><span class=\"token punctuation\">(<\/span>Widget rhs<span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span>  <span class=\"token comment\">\/\/ \u6ce8\u610f&#xff1a;\u6309\u503c\u4f20\u53c2&#xff0c;move \u6216 copy \u90fd\u5728\u8fd9\u4e00\u6b65\u5b8c\u6210<\/span><br \/>\n    <span class=\"token function\">swap<\/span><span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">,<\/span> rhs<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> <span class=\"token operator\">*<\/span><span class=\"token keyword\">this<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<p>\u5982\u679c\u4f20\u5165\u7684\u662f\u53f3\u503c&#xff0c;rhs \u901a\u8fc7 move \u6784\u9020&#xff0c;\u51e0\u4e4e\u96f6\u6210\u672c&#xff1b;\u5982\u679c\u662f\u5de6\u503c&#xff0c;\u6b63\u5e38 copy\u3002\u7136\u540e\u7edf\u4e00 swap\u3002\u8fd9\u5c31\u662f\u6240\u8c13\u7684&#034;\u7edf\u4e00\u8d4b\u503c\u8fd0\u7b97\u7b26&#034;\u2014\u2014\u4e00\u4e2a\u51fd\u6570\u540c\u65f6\u5904\u7406 copy \u548c move \u8d4b\u503c&#xff0c;\u4e14\u5929\u7136\u5f02\u5e38\u5b89\u5168\u3002<\/p>\n<p>\u4f46\u6761\u6b3e29 \u63cf\u8ff0\u7684&#034;\u5728\u526f\u672c\u4e0a\u505a\u591a\u6b65\u4fee\u6539\u518d\u63d0\u4ea4&#034;\u7684\u6a21\u5f0f\u4ecd\u7136\u9700\u8981\u771f\u6b63\u7684\u6df1\u62f7\u8d1d&#xff0c;\u79fb\u52a8\u8bed\u4e49\u5e2e\u4e0d\u4e86\u4f60\u2014\u2014\u56e0\u4e3a\u4f60\u9700\u8981\u4fdd\u7559\u539f\u4ef6\u76f4\u5230\u4fee\u6539\u5168\u90e8\u6210\u529f\u3002<\/p>\n<p>&#x1f4d6; \u5f02\u5e38\u5b89\u5168\u7684\u4e09\u4e2a\u4fdd\u8bc1\u7b49\u7ea7\u662f\u51fd\u6570\u63a5\u53e3\u7684\u4e00\u90e8\u5206&#xff0c;\u5e94\u8be5\u50cf\u9009\u62e9\u53c2\u6570\u7c7b\u578b\u4e00\u6837\u614e\u91cd\u51b3\u7b56\u3002copy-and-swap \u662f\u5b9e\u73b0\u5f3a\u70c8\u4fdd\u8bc1\u7684\u5178\u578b\u7b56\u7565&#xff0c;\u4f46\u4e0d\u662f\u6240\u6709\u51fd\u6570\u90fd\u8be5\u8ffd\u6c42\u5f3a\u70c8\u4fdd\u8bc1\u2014\u2014\u57fa\u672c\u627f\u8bfa\u5bf9\u5f88\u591a\u573a\u666f\u5df2\u7ecf\u8db3\u591f\u4e14\u52a1\u5b9e\u3002<\/p>\n<hr \/>\n<h2>\u516d\u3001\u6761\u6b3e30&#xff1a;\u900f\u5f7b\u4e86\u89e3 inlining \u7684\u91cc\u91cc\u5916\u5916<\/h2>\n<p>Understand the ins and outs of inlining.<\/p>\n<h3>1. inline \u662f\u7533\u8bf7\u4e0d\u662f\u547d\u4ee4<\/h3>\n<p>inline \u53ea\u662f\u5bf9\u7f16\u8bd1\u5668\u7684\u7533\u8bf7&#xff0c;\u7f16\u8bd1\u5668\u53ef\u4ee5\u62d2\u7edd\u3002\u4e24\u79cd\u7533\u8bf7\u65b9\u5f0f&#xff1a;<\/p>\n<ul>\n<li>\u9690\u55bb&#xff1a;\u6210\u5458\u51fd\u6570\u5b9a\u4e49\u5728 class \u5b9a\u4e49\u5f0f\u5185<\/li>\n<li>\u660e\u786e&#xff1a;\u51fd\u6570\u5b9a\u4e49\u524d\u52a0 inline \u5173\u952e\u5b57<\/li>\n<\/ul>\n<p>\u7f16\u8bd1\u5668\u901a\u5e38\u62d2\u7edd inline \u592a\u590d\u6742\u7684\u51fd\u6570&#xff08;\u5e26\u5faa\u73af\u3001\u9012\u5f52&#xff09;&#xff0c;\u800c\u5bf9 virtual \u51fd\u6570\u7684\u8c03\u7528&#xff08;\u9664\u975e\u7f16\u8bd1\u5668\u80fd\u5728\u7f16\u8bd1\u671f\u786e\u5b9a\u5b9e\u9645\u7c7b\u578b&#xff09;\u4e5f\u4e0d\u4f1a inline\u2014\u2014\u56e0\u4e3a virtual \u610f\u5473\u7740&#034;\u8fd0\u884c\u671f\u624d\u77e5\u9053\u8c03\u54ea\u4e2a&#034;&#xff0c;inline \u610f\u5473\u7740&#034;\u7f16\u8bd1\u671f\u66ff\u6362\u51fd\u6570\u4f53&#034;&#xff0c;\u4e24\u8005\u77db\u76fe\u3002<\/p>\n<h3>2. inline \u7684\u6210\u672c&#xff1a;\u4ee3\u7801\u81a8\u80c0<\/h3>\n<p>inline \u7684\u903b\u8f91\u662f&#034;\u6bcf\u4e2a\u8c03\u7528\u70b9\u90fd\u66ff\u6362\u6210\u51fd\u6570\u4f53&#034;\u3002\u5982\u679c\u51fd\u6570\u4f53\u5f88\u5c0f&#xff0c;\u66ff\u6362\u540e\u7684\u4ee3\u7801\u53ef\u80fd\u6bd4&#034;\u8c03\u7528\u51fd\u6570&#043;\u4f20\u53c2&#043;\u8fd4\u56de&#034;\u7684\u4ee3\u7801\u8fd8\u5c0f\u2014\u2014\u53cd\u800c\u7701\u7a7a\u95f4\u3002\u4f46\u5982\u679c\u51fd\u6570\u4f53\u8f83\u5927\u4e14\u88ab\u8c03\u7528\u5f88\u591a\u6b21&#xff0c;inline \u4f1a\u5bfc\u81f4\u76ee\u6807\u4ee3\u7801\u66b4\u6da8&#xff1a;<\/p>\n<ul>\n<li>\u66f4\u5927\u7684\u53ef\u6267\u884c\u6587\u4ef6<\/li>\n<li>\u66f4\u591a\u7684\u6362\u9875&#xff08;paging&#xff09;\u884c\u4e3a<\/li>\n<li>\u66f4\u4f4e\u7684\u6307\u4ee4\u7f13\u5b58\u547d\u4e2d\u7387&#xff08;instruction cache hit rate&#xff09;<\/li>\n<\/ul>\n<p>\u5373\u4f7f\u6709\u865a\u5185\u5b58&#xff0c;\u4ee3\u7801\u81a8\u80c0\u5e26\u6765\u7684\u7f13\u5b58\u6296\u52a8\u4e5f\u4f1a\u5b9e\u5b9e\u5728\u5728\u5730\u62d6\u6162\u901f\u5ea6\u3002<\/p>\n<h3>3. \u5373\u4f7f\u7f16\u8bd1\u5668\u613f\u610f inline&#xff0c;\u4e5f\u53ef\u80fd\u751f\u6210 outlined \u526f\u672c<\/h3>\n<p>\u5f53\u4f60\u53d6\u4e00\u4e2a inline \u51fd\u6570\u7684\u5730\u5740\u65f6&#xff0c;\u7f16\u8bd1\u5668\u5fc5\u987b\u751f\u6210\u4e00\u4e2a outlined \u7684\u51fd\u6570\u672c\u4f53\u2014\u2014\u5426\u5219\u6307\u9488\u6307\u5411\u4ec0\u4e48&#xff1f;\u901a\u8fc7\u51fd\u6570\u6307\u9488\u7684\u8c03\u7528\u901a\u5e38\u4e0d\u4f1a\u88ab inline&#xff1a;<\/p>\n<p><span class=\"token keyword\">inline<\/span> <span class=\"token keyword\">void<\/span> <span class=\"token function\">f<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span> <span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span><span class=\"token punctuation\">.<\/span> <span class=\"token punctuation\">}<\/span><\/p>\n<p><span class=\"token keyword\">void<\/span> <span class=\"token punctuation\">(<\/span><span class=\"token operator\">*<\/span>pf<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token operator\">&#061;<\/span> f<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u9700\u8981 outlined f \u7684\u5730\u5740<\/span><br \/>\n<span class=\"token function\">f<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>    <span class=\"token comment\">\/\/ \u6b63\u5e38\u8c03\u7528&#xff0c;\u53ef\u80fd\u88ab inlined<\/span><br \/>\n<span class=\"token function\">pf<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u901a\u8fc7\u51fd\u6570\u6307\u9488\u8c03\u7528&#xff0c;\u901a\u5e38\u4e0d\u4f1a inlined<\/span><\/p>\n<p>\u6784\u9020\u51fd\u6570\u548c\u6790\u6784\u51fd\u6570\u770b\u8d77\u6765\u662f inline \u7684\u7edd\u4f73\u5019\u9009&#xff08;\u7a7a\u51fd\u6570&#xff01;&#xff09;&#xff0c;\u4f46\u5b9e\u9645\u4e0a\u5b83\u4eec\u662f\u7cdf\u7cd5\u7684 inline \u5019\u9009\u4eba\u3002C&#043;&#043; \u4fdd\u8bc1&#034;\u521b\u5efa\u5bf9\u8c61\u65f6\u6bcf\u4e2a\u57fa\u7c7b\u548c\u6210\u5458\u90fd\u88ab\u6784\u9020&#034;\u201c\u6790\u6784\u65f6\u53cd\u5411\u6790\u6784\u201d&#xff0c;\u7f16\u8bd1\u5668\u4f1a\u5728\u7a7a\u6784\u9020\u51fd\u6570\u91cc\u63d2\u5165\u5927\u91cf\u4ee3\u7801\u2014\u2014\u8c03\u7528\u6210\u5458\u53d8\u91cf\u6784\u9020\u51fd\u6570\u3001\u57fa\u7c7b\u6784\u9020\u51fd\u6570\u3001\u5f02\u5e38\u5904\u7406\u6808\u5c55\u5f00\u903b\u8f91\u7b49\u3002\u5982\u679c\u8fd9\u4e9b\u6784\u9020\u51fd\u6570\u53c8\u6070\u597d\u662f inline \u7684&#xff0c;\u5c42\u5c42\u5c55\u5f00\u540e&#xff0c;\u4e00\u4e2a&#034;\u7a7a\u6784\u9020\u51fd\u6570&#034;\u53ef\u80fd\u81a8\u80c0\u6210\u4e00\u5927\u5768\u4ee3\u7801\u3002<\/p>\n<h3>4. inline \u51fd\u6570\u65e0\u6cd5\u968f\u5e93\u5347\u7ea7\u800c\u5347\u7ea7<\/h3>\n<p>\u8fd9\u662f\u5bf9\u5e93\u8bbe\u8ba1\u8005\u7279\u522b\u91cd\u8981\u7684\u4e00\u70b9\u3002\u5982\u679c f \u662f inline \u51fd\u6570&#xff0c;\u5ba2\u6237\u628a\u51fd\u6570\u4f53\u7f16\u8fdb\u4e86\u81ea\u5df1\u7684\u7a0b\u5e8f\u3002\u4e00\u65e6\u5e93\u8bbe\u8ba1\u8005\u4fee\u6539\u4e86 f&#xff0c;\u6240\u6709\u5ba2\u6237\u5fc5\u987b\u91cd\u65b0\u7f16\u8bd1\u3002\u5982\u679c f \u662f\u975e inline \u7684&#xff0c;\u5ba2\u6237\u53ea\u9700\u8981\u91cd\u65b0\u8fde\u63a5&#xff08;\u52a8\u6001\u8fde\u63a5\u65f6\u751a\u81f3\u65e0\u611f\u5347\u7ea7&#xff09;\u3002<\/p>\n<p>\u8c03\u8bd5\u5668\u5bf9 inline \u51fd\u6570\u4e5f\u5f88\u4e0d\u53cb\u597d\u2014\u2014\u4f60\u600e\u4e48\u5728\u4e00\u4e2a\u4e0d\u5b58\u5728\u7684\u51fd\u6570\u91cc\u8bbe\u65ad\u70b9&#xff1f;<\/p>\n<h3>5. 80-20 \u6cd5\u5219<\/h3>\n<p>\u5e73\u5747\u800c\u8a00&#xff0c;\u7a0b\u5e8f\u628a 80% \u7684\u6267\u884c\u65f6\u95f4\u82b1\u5728 20% \u7684\u4ee3\u7801\u4e0a\u3002<\/p>\n<p>inline \u5e94\u8be5\u96c6\u4e2d\u5728\u90a3 20% \u7684\u3001\u5c0f\u578b\u3001\u9891\u7e41\u8c03\u7528\u7684\u51fd\u6570\u4e0a\u3002\u5148\u522b inline&#xff0c;\u7528 profiler \u627e\u51fa\u771f\u6b63\u7684\u70ed\u70b9&#xff0c;\u518d\u9488\u5bf9\u6027\u4f18\u5316\u3002<\/p>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;inline \u4e0e template \u7684\u5173\u7cfb<\/h3>\n<p>Q&#xff1a;\u6761\u6b3e\u7279\u522b\u63d0\u9192&#034;\u4e0d\u8981\u56e0\u4e3a template \u5728\u5934\u6587\u4ef6\u91cc\u5c31\u628a\u5b83\u58f0\u660e\u4e3a inline&#034;&#xff0c;\u8fd9\u4e24\u8005\u4e3a\u4ec0\u4e48\u7ecf\u5e38\u88ab\u6df7\u6dc6&#xff1f;<\/p>\n<p>\u6df7\u6dc6\u7684\u6839\u6e90\u662f&#xff1a;inline \u51fd\u6570\u548c function template \u901a\u5e38\u90fd\u653e\u5728\u5934\u6587\u4ef6\u91cc&#xff0c;\u4f46\u539f\u56e0\u5b8c\u5168\u4e0d\u540c&#xff1a;<\/p>\n<table>\n<tr>\u7279\u6027\u4e3a\u4ec0\u4e48\u5728\u5934\u6587\u4ef6\u542b\u4e49<\/tr>\n<tbody>\n<tr>\n<td>inline \u51fd\u6570<\/td>\n<td>\u7f16\u8bd1\u5668\u9700\u8981\u5728\u8c03\u7528\u70b9\u770b\u5230\u51fd\u6570\u4f53\u624d\u80fd\u66ff\u6362<\/td>\n<td>\u51fd\u6570\u4f53\u5728\u7f16\u8bd1\u671f\u53ef\u7528<\/td>\n<\/tr>\n<tr>\n<td>function template<\/td>\n<td>\u7f16\u8bd1\u5668\u9700\u8981\u5728\u5177\u73b0\u5316\u65f6\u770b\u5230\u6a21\u677f\u5b9a\u4e49\u624d\u80fd\u751f\u6210\u4ee3\u7801<\/td>\n<td>\u6a21\u677f\u5b9a\u4e49\u5728\u7f16\u8bd1\u671f\u53ef\u7528<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u4e24\u8005\u7684\u5171\u540c\u70b9\u662f&#034;\u5b9a\u4e49\u5fc5\u987b\u5728\u7f16\u8bd1\u671f\u53ef\u89c1&#034;&#xff0c;\u4f46\u8fd9\u4e0d\u610f\u5473\u7740 template \u5fc5\u987b\u662f inline \u7684\u3002Template \u5177\u73b0\u5316\u51fa\u7684\u51fd\u6570\u53ef\u4ee5\u662f\u666e\u901a\u7684 outlined \u51fd\u6570\u2014\u2014\u6bcf\u4e2a\u7ffb\u8bd1\u5355\u5143\u751f\u6210\u4e00\u4efd&#xff0c;\u94fe\u63a5\u5668\u8d1f\u8d23\u53bb\u91cd&#xff08;COMDAT \u6bb5&#xff09;\u3002<\/p>\n<p>\u5982\u679c\u4f60\u7ed9 template \u52a0\u4e0a inline&#xff0c;\u610f\u5473\u7740\u4f60\u8981\u6c42\u6240\u6709\u5177\u73b0\u5316\u7248\u672c\u90fd\u5c1d\u8bd5 inline&#xff0c;\u8fd9\u5bf9\u590d\u6742\u6a21\u677f&#xff08;\u5982 std::sort\u3001std::transform&#xff09;\u4f1a\u5bfc\u81f4\u4e25\u91cd\u7684\u4ee3\u7801\u81a8\u80c0\u3002\u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u6807\u51c6\u5e93\u7b97\u6cd5\u867d\u7136\u5168\u5728\u5934\u6587\u4ef6\u91cc&#xff0c;\u4f46\u7edd\u5927\u591a\u6570\u4e0d\u662f inline \u7684\u3002<\/p>\n<p>C&#043;&#043;17 \u5f15\u5165\u7684 inline \u53d8\u91cf\u548c C&#043;&#043;20 \u7684 modules \u6b63\u5728\u9010\u6b65\u6539\u53d8\u5934\u6587\u4ef6\u7684\u7ec4\u7ec7\u65b9\u5f0f&#xff0c;\u4f46&#034;template \u2260 inline&#034;\u8fd9\u4e2a\u539f\u5219\u4f9d\u7136\u6210\u7acb\u3002<\/p>\n<p>&#x1f4d6; inline \u662f\u4e00\u79cd\u6027\u80fd\u4f18\u5316\u624b\u6bb5&#xff0c;\u4e0d\u662f\u9ed8\u8ba4\u9009\u9879\u3002\u5b83\u7684\u4ee3\u4ef7\u662f\u4ee3\u7801\u81a8\u80c0\u3001\u7f16\u8bd1\u8026\u5408\u548c\u8c03\u8bd5\u56f0\u96be\u3002\u9075\u5faa 80-20 \u6cd5\u5219&#xff0c;\u53ea\u5bf9\u5c0f\u578b\u3001\u9ad8\u9891\u3001\u786e\u8ba4\u4e3a\u70ed\u70b9\u7684\u51fd\u6570 inline&#xff0c;\u5176\u4f59\u4fdd\u6301 outlined\u3002<\/p>\n<hr \/>\n<h2>\u4e03\u3001\u6761\u6b3e31&#xff1a;\u5c06\u6587\u4ef6\u95f4\u7684\u7f16\u8bd1\u4f9d\u5b58\u5173\u7cfb\u964d\u81f3\u6700\u4f4e<\/h2>\n<p>Minimize compilation dependencies between files.<\/p>\n<h3>1. \u95ee\u9898&#xff1a;\u6539\u4e00\u4e2a private \u6210\u5458&#xff0c;\u5168\u4e16\u754c\u91cd\u7f16\u8bd1<\/h3>\n<p><span class=\"token comment\">\/\/ person.h<\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;string&gt;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&#034;date.h&#034;<\/span><\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&#034;address.h&#034;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Person<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">Person<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Date<span class=\"token operator\">&amp;<\/span> birthday<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Address<span class=\"token operator\">&amp;<\/span> addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">name<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">birthDate<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">address<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string theName<span class=\"token punctuation\">;<\/span><br \/>\n    Date theBirthDate<span class=\"token punctuation\">;<\/span><br \/>\n    Address theAddress<span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5982\u679c\u4f60\u5728 Person \u7684 private \u533a\u52a0\u4e00\u4e2a int \u6210\u5458&#xff0c;\u6240\u6709 #include &#034;person.h&#034; \u7684\u6587\u4ef6\u90fd\u8981\u91cd\u7f16\u8bd1\u3002\u66f4\u7cdf\u7684\u662f&#xff0c;date.h \u6216 address.h \u7684\u4efb\u4f55\u6539\u52a8\u4e5f\u4f1a\u7ea7\u8054\u89e6\u53d1\u91cd\u7f16\u8bd1\u3002<\/p>\n<p>\u95ee\u9898\u7684\u6839\u6e90\u662f&#xff1a;C&#043;&#043; \u7f16\u8bd1\u5668\u5728\u7f16\u8bd1\u671f\u5fc5\u987b\u77e5\u9053\u5bf9\u8c61\u7684\u5927\u5c0f&#xff0c;\u800c\u5927\u5c0f\u53d6\u51b3\u4e8e class \u5b9a\u4e49\u5f0f\u4e2d\u5217\u51fa\u7684\u6240\u6709\u6210\u5458\u3002\u5982\u679c\u4f60\u53ea\u524d\u7f6e\u58f0\u660e class Date;&#xff0c;\u7f16\u8bd1\u5668\u4e0d\u77e5\u9053 Date \u591a\u5927&#xff0c;\u5c31\u6ca1\u6cd5\u7b97 Person \u591a\u5927\u3002<\/p>\n<h3>2. pimpl \u624b\u6cd5&#xff1a;\u58f0\u660e\u4f9d\u5b58\u6027\u66ff\u6362\u5b9a\u4e49\u4f9d\u5b58\u6027<\/h3>\n<p>\u6838\u5fc3\u601d\u8def&#xff1a;\u628a\u5b9e\u73b0\u7ec6\u8282\u85cf\u5230\u4e00\u4e2a\u6307\u9488\u80cc\u540e&#xff0c;\u8ba9\u5934\u6587\u4ef6\u53ea\u4f9d\u8d56\u58f0\u660e&#xff0c;\u4e0d\u4f9d\u8d56\u5b9a\u4e49\u3002<\/p>\n<p><span class=\"token comment\">\/\/ person.h<\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&lt;memory&gt;<\/span><\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">PersonImpl<\/span><span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u524d\u7f6e\u58f0\u660e\u5b9e\u73b0\u7c7b<\/span><br \/>\n<span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Date<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Address<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Person<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token function\">Person<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Date<span class=\"token operator\">&amp;<\/span> birthday<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Address<span class=\"token operator\">&amp;<\/span> addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">name<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">birthDate<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">address<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token keyword\">private<\/span><span class=\"token operator\">:<\/span><br \/>\n    std<span class=\"token double-colon punctuation\">::<\/span>tr1<span class=\"token double-colon punctuation\">::<\/span>shared_ptr<span class=\"token operator\">&lt;<\/span>PersonImpl<span class=\"token operator\">&gt;<\/span> pImpl<span class=\"token punctuation\">;<\/span>  <span class=\"token comment\">\/\/ \u6307\u9488&#xff0c;\u5927\u5c0f\u56fa\u5b9a<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5ba2\u6237\u53ea\u9700\u8981 #include &#034;person.h&#034;&#xff0c;person.h \u4e0d\u518d include date.h \u548c address.h\u3002Date\u3001Address\u3001PersonImpl \u7684\u5b9e\u73b0\u6539\u52a8\u4e0d\u4f1a\u89e6\u53d1\u5ba2\u6237\u91cd\u7f16\u8bd1\u3002<\/p>\n<p><span class=\"token comment\">\/\/ person.cpp<\/span><br \/>\n<span class=\"token macro property\"><span class=\"token directive-hash\">#<\/span><span class=\"token directive keyword\">include<\/span> <span class=\"token string\">&#034;PersonImpl.h&#034;<\/span>  <span class=\"token comment\">\/\/ \u5b9e\u73b0\u6587\u4ef6\u624d include \u771f\u6b63\u7684\u5b9a\u4e49<\/span><\/span><\/p>\n<p><span class=\"token class-name\">Person<\/span><span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">Person<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Date<span class=\"token operator\">&amp;<\/span> birthday<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Address<span class=\"token operator\">&amp;<\/span> addr<span class=\"token punctuation\">)<\/span><br \/>\n    <span class=\"token operator\">:<\/span> <span class=\"token function\">pImpl<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">new<\/span> <span class=\"token function\">PersonImpl<\/span><span class=\"token punctuation\">(<\/span>name<span class=\"token punctuation\">,<\/span> birthday<span class=\"token punctuation\">,<\/span> addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token punctuation\">{<\/span><span class=\"token punctuation\">}<\/span><\/p>\n<p>std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token class-name\">Person<\/span><span class=\"token double-colon punctuation\">::<\/span><span class=\"token function\">name<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n    <span class=\"token keyword\">return<\/span> pImpl<span class=\"token operator\">-&gt;<\/span><span class=\"token function\">name<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><\/p>\n<h3>3. \u4e24\u79cd\u89e3\u8026\u624b\u6bb5<\/h3>\n<h4>Handle class&#xff08;\u53e5\u67c4\u7c7b&#xff09;<\/h4>\n<p>\u5c31\u662f\u4e0a\u9762\u7684 pimpl \u624b\u6cd5\u3002Person \u662f\u4e00\u4e2a&#034;\u624b\u67c4&#034;&#xff0c;\u6240\u6709\u8c03\u7528\u8f6c\u53d1\u7ed9 PersonImpl\u3002<\/p>\n<h4>Interface class&#xff08;\u63a5\u53e3\u7c7b&#xff09;<\/h4>\n<p>\u7c7b\u4f3c Java\/C# \u7684 interface&#xff1a;\u62bd\u8c61\u57fa\u7c7b&#xff0c;\u53ea\u6709\u7eaf\u865a\u51fd\u6570&#xff0c;\u6ca1\u6709\u6210\u5458\u53d8\u91cf&#xff1a;<\/p>\n<p><span class=\"token keyword\">class<\/span> <span class=\"token class-name\">Person<\/span> <span class=\"token punctuation\">{<\/span><br \/>\n<span class=\"token keyword\">public<\/span><span class=\"token operator\">:<\/span><br \/>\n    <span class=\"token keyword\">virtual<\/span> <span class=\"token operator\">~<\/span><span class=\"token function\">Person<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">virtual<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">name<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">virtual<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">birthDate<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><br \/>\n    <span class=\"token keyword\">virtual<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string <span class=\"token function\">address<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span> <span class=\"token keyword\">const<\/span> <span class=\"token operator\">&#061;<\/span> <span class=\"token number\">0<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>    <span class=\"token comment\">\/\/ factory \u51fd\u6570<\/span><br \/>\n    <span class=\"token keyword\">static<\/span> std<span class=\"token double-colon punctuation\">::<\/span>tr1<span class=\"token double-colon punctuation\">::<\/span>shared_ptr<span class=\"token operator\">&lt;<\/span>Person<span class=\"token operator\">&gt;<\/span> <span class=\"token function\">create<\/span><span class=\"token punctuation\">(<\/span><br \/>\n        <span class=\"token keyword\">const<\/span> std<span class=\"token double-colon punctuation\">::<\/span>string<span class=\"token operator\">&amp;<\/span> name<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Date<span class=\"token operator\">&amp;<\/span> birthday<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">const<\/span> Address<span class=\"token operator\">&amp;<\/span> addr<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><br \/>\n<span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span><\/p>\n<p>\u5ba2\u6237\u901a\u8fc7 Person::create() \u521b\u5efa\u5bf9\u8c61&#xff0c;\u62ff\u5230\u7684\u662f shared_ptr&lt;Person&gt;&#xff0c;\u8c03\u7528\u865a\u51fd\u6570\u3002\u771f\u6b63\u7684\u5b9e\u73b0\u85cf\u5728\u6d3e\u751f\u7c7b RealPerson \u91cc\u3002<\/p>\n<p>\u4e24\u79cd\u624b\u6bb5\u7684\u5bf9\u6bd4&#xff1a;<\/p>\n<table>\n<tr>Handle classInterface class<\/tr>\n<tbody>\n<tr>\n<td>\u673a\u5236<\/td>\n<td>\u6307\u9488\u8f6c\u53d1<\/td>\n<td>\u865a\u51fd\u6570\u591a\u6001<\/td>\n<\/tr>\n<tr>\n<td>\u8fd0\u884c\u65f6\u6210\u672c<\/td>\n<td>\u6bcf\u6b21\u8bbf\u95ee\u591a\u4e00\u5c42\u95f4\u63a5\u8df3\u8f6c<\/td>\n<td>\u6bcf\u6b21\u8c03\u7528\u4e00\u6b21\u865a\u51fd\u6570\u8df3\u8f6c<\/td>\n<\/tr>\n<tr>\n<td>\u5185\u5b58\u6210\u672c<\/td>\n<td>\u6bcf\u4e2a\u5bf9\u8c61\u591a\u4e00\u4e2a\u6307\u9488<\/td>\n<td>\u6bcf\u4e2a\u5bf9\u8c61\u591a\u4e00\u4e2a vptr<\/td>\n<\/tr>\n<tr>\n<td>\u9002\u5408\u573a\u666f<\/td>\n<td>\u5b9e\u73b0\u7ec6\u8282\u53d8\u5316\u9891\u7e41<\/td>\n<td>\u6709\u591a\u4e2a\u6d3e\u751f\u5b9e\u73b0<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>4. \u5b9e\u8df5\u5efa\u8bae<\/h3>\n<ul>\n<li>\u80fd\u7528\u5f15\u7528\/\u6307\u9488\u5c31\u522b\u7528\u503c\u5bf9\u8c61&#xff08;\u5f15\u7528\/\u6307\u9488\u53ea\u9700\u8981\u58f0\u660e&#xff0c;\u503c\u9700\u8981\u5b9a\u4e49&#xff09;<\/li>\n<li>\u5934\u6587\u4ef6\u5c3d\u91cf\u53ea\u542b\u58f0\u660e&#xff0c;\u4f9d\u8d56\u901a\u8fc7\u524d\u7f6e\u58f0\u660e\u800c\u975e include<\/li>\n<li>\u4e3a\u58f0\u660e\u548c\u5b9a\u4e49\u63d0\u4f9b\u4e0d\u540c\u5934\u6587\u4ef6&#xff08;\u5982 datefwd.h \u53ea\u58f0\u660e Date&#xff0c;date.h \u624d\u5b9a\u4e49&#xff09;&#xff0c;\u6807\u51c6\u5e93\u7684 &lt;iosfwd&gt; \u5c31\u662f\u8303\u672c<\/li>\n<li>\u7528\u6e10\u8fdb\u65b9\u5f0f&#xff1a;\u5f00\u53d1\u9636\u6bb5\u7528 Handle\/Interface \u89e3\u8026&#xff0c;\u53ea\u6709\u5f53\u6027\u80fd\/\u5927\u5c0f\u5dee\u5f02\u6210\u4e3a\u74f6\u9888\u65f6\u624d\u6362\u56de\u5177\u8c61\u7c7b<\/li>\n<\/ul>\n<h3>\u6df1\u5ea6\u601d\u8003&#xff1a;C&#043;&#043;20 modules \u662f\u5426\u7ec8\u7ed3\u4e86 pimpl<\/h3>\n<p>Q&#xff1a;C&#043;&#043;20 \u5f15\u5165\u4e86 modules&#xff0c;\u58f0\u79f0\u80fd\u5927\u5e45\u6539\u5584\u7f16\u8bd1\u65f6\u95f4\u548c\u5934\u6587\u4ef6\u4f9d\u8d56\u3002pimpl \u662f\u5426\u8fd8\u6709\u5b58\u5728\u5fc5\u8981&#xff1f;<\/p>\n<p>Modules \u786e\u5b9e\u89e3\u51b3\u4e86\u4e00\u90e8\u5206\u95ee\u9898&#xff1a;import \u4e0d\u4f1a\u50cf #include \u90a3\u6837\u9012\u5f52\u5c55\u5f00\u6240\u6709\u5934\u6587\u4ef6&#xff0c;\u6a21\u5757\u63a5\u53e3\u53ef\u4ee5\u7cbe\u786e\u63a7\u5236\u54ea\u4e9b\u540d\u79f0\u5bfc\u51fa\u3002\u4f46 pimpl \u7684\u4ef7\u503c\u4e0d\u5b8c\u5168\u5728\u4e8e\u7f16\u8bd1\u901f\u5ea6&#xff1a;<\/p>\n<table>\n<tr>pimpl \u7684\u4ef7\u503cmodules \u662f\u5426\u89e3\u51b3<\/tr>\n<tbody>\n<tr>\n<td>\u964d\u4f4e\u7f16\u8bd1\u4f9d\u5b58\u6027<\/td>\n<td>\u2705 \u90e8\u5206\u89e3\u51b3\u2014\u2014modules \u51cf\u5c11\u4e86\u5b8f\u6cc4\u6f0f\u548c\u4f20\u9012\u6027 include<\/td>\n<\/tr>\n<tr>\n<td>\u4e8c\u8fdb\u5236\u517c\u5bb9\u6027<\/td>\n<td>\u274c \u672a\u89e3\u51b3\u2014\u2014\u6539\u53d8\u79c1\u6709\u6210\u5458\u4ecd\u7136\u6539\u53d8\u7c7b\u5e03\u5c40\u548c\u5927\u5c0f<\/td>\n<\/tr>\n<tr>\n<td>\u9690\u85cf\u5b9e\u73b0\u7ec6\u8282<\/td>\n<td>\u26a0\ufe0f \u90e8\u5206\u89e3\u51b3\u2014\u2014\u6a21\u5757\u53ef\u4ee5\u4e0d\u5bfc\u51fa\u5b9e\u73b0&#xff0c;\u4f46\u63a5\u53e3\u7c7b\u4ecd\u66b4\u9732\u79c1\u6709\u6210\u5458\u58f0\u660e<\/td>\n<\/tr>\n<tr>\n<td>\u63a5\u53e3\u4e0e\u5b9e\u73b0\u7269\u7406\u5206\u79bb<\/td>\n<td>\u274c modules \u662f\u903b\u8f91\u5206\u79bb&#xff0c;\u4e0d\u662f\u7269\u7406\u5206\u79bb<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u7279\u522b\u91cd\u8981\u7684\u662f\u4e8c\u8fdb\u5236\u517c\u5bb9\u6027\u3002\u5982\u679c\u4f60\u5728\u5f00\u53d1\u4e00\u4e2a\u52a8\u6001\u5e93&#xff08;.so\/.dll&#xff09;&#xff0c;\u5ba2\u6237\u7684\u7a0b\u5e8f\u94fe\u63a5\u4f60\u7684\u5e93\u3002pimpl \u5141\u8bb8\u4f60\u5728\u65b0\u7248\u672c\u4e2d\u589e\u5220\u79c1\u6709\u6210\u5458\u800c\u4e0d\u6539\u53d8\u7c7b\u7684\u5927\u5c0f\u548c\u5e03\u5c40\u2014\u2014\u5ba2\u6237\u4e0d\u9700\u8981\u91cd\u65b0\u7f16\u8bd1\u3002modules \u505a\u4e0d\u5230\u8fd9\u4e00\u70b9&#xff0c;\u56e0\u4e3a\u6a21\u5757\u63a5\u53e3\u4ecd\u7136\u63cf\u8ff0\u4e86\u7c7b\u7684\u5b8c\u6574\u5e03\u5c40\u3002<\/p>\n<p>\u6240\u4ee5 pimpl \u5728\u4ee5\u4e0b\u573a\u666f\u4ecd\u7136\u662f\u9996\u9009&#xff1a;<\/p>\n<ul>\n<li>\u5546\u4e1a\u52a8\u6001\u5e93&#xff0c;\u9700\u8981\u8de8\u7248\u672c\u4e8c\u8fdb\u5236\u517c\u5bb9<\/li>\n<li>\u9690\u85cf\u5e73\u53f0\u76f8\u5173\u4ee3\u7801&#xff08;#ifdef \u57cb\u5728 cpp \u91cc&#xff09;<\/li>\n<li>\u51cf\u5c11\u5934\u6587\u4ef6\u5bf9\u91cd\u578b\u4f9d\u8d56&#xff08;\u5982 Boost\u3001\u7b2c\u4e09\u65b9\u5e93&#xff09;\u7684\u66b4\u9732<\/li>\n<\/ul>\n<p>\u5bf9\u4e8e\u666e\u901a\u5e94\u7528\u5f00\u53d1\u3001\u4e0d\u6d89\u53ca\u4e8c\u8fdb\u5236\u5206\u53d1\u7684\u5185\u90e8\u9879\u76ee&#xff0c;modules \u914d\u5408\u524d\u7f6e\u58f0\u660e\u53ef\u80fd\u5df2\u7ecf\u8db3\u591f&#xff0c;pimpl \u7684\u95f4\u63a5\u8df3\u8f6c\u6210\u672c\u4e0d\u503c\u5f97\u3002<\/p>\n<p>&#x1f4d6; \u7f16\u8bd1\u4f9d\u5b58\u6027\u6700\u5c0f\u5316\u7684\u672c\u8d28\u662f&#034;\u76f8\u4f9d\u4e8e\u58f0\u660e\u5f0f&#xff0c;\u4e0d\u8981\u76f8\u4f9d\u4e8e\u5b9a\u4e49\u5f0f&#034;\u3002Handle class \u548c Interface class \u662f\u4e24\u79cd\u5b9e\u73b0\u624b\u6bb5&#xff0c;\u5404\u6709\u8fd0\u884c\u65f6\u6210\u672c\u3002\u662f\u5426\u503c\u5f97\u53d6\u51b3\u4e8e\u9879\u76ee\u89c4\u6a21\u3001\u53d1\u5e03\u65b9\u5f0f\u548c\u6027\u80fd\u654f\u611f\u5ea6\u3002<\/p>\n<hr \/>\n<h2>\u516b\u3001\u77e5\u8bc6\u7ed3\u6784\u56fe<\/h2>\n<p>  #mermaid-svg-NDKNkiLggZDPn6aZ{font-family:\\&#8221;trebuchet ms\\&#8221;,verdana,arial,sans-serif;font-size:16px;fill:#333;}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#mermaid-svg-NDKNkiLggZDPn6aZ .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#mermaid-svg-NDKNkiLggZDPn6aZ .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#mermaid-svg-NDKNkiLggZDPn6aZ .error-icon{fill:#552222;}#mermaid-svg-NDKNkiLggZDPn6aZ .error-text{fill:#552222;stroke:#552222;}#mermaid-svg-NDKNkiLggZDPn6aZ .edge-thickness-normal{stroke-width:1px;}#mermaid-svg-NDKNkiLggZDPn6aZ .edge-thickness-thick{stroke-width:3.5px;}#mermaid-svg-NDKNkiLggZDPn6aZ .edge-pattern-solid{stroke-dasharray:0;}#mermaid-svg-NDKNkiLggZDPn6aZ .edge-thickness-invisible{stroke-width:0;fill:none;}#mermaid-svg-NDKNkiLggZDPn6aZ 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polygon,#mermaid-svg-NDKNkiLggZDPn6aZ .node path{fill:#ECECFF;stroke:#9370DB;stroke-width:1px;}#mermaid-svg-NDKNkiLggZDPn6aZ .rough-node .label text,#mermaid-svg-NDKNkiLggZDPn6aZ .node .label text,#mermaid-svg-NDKNkiLggZDPn6aZ .image-shape .label,#mermaid-svg-NDKNkiLggZDPn6aZ .icon-shape .label{text-anchor:middle;}#mermaid-svg-NDKNkiLggZDPn6aZ .node .katex path{fill:#000;stroke:#000;stroke-width:1px;}#mermaid-svg-NDKNkiLggZDPn6aZ .rough-node .label,#mermaid-svg-NDKNkiLggZDPn6aZ .node .label,#mermaid-svg-NDKNkiLggZDPn6aZ .image-shape .label,#mermaid-svg-NDKNkiLggZDPn6aZ .icon-shape .label{text-align:center;}#mermaid-svg-NDKNkiLggZDPn6aZ .node.clickable{cursor:pointer;}#mermaid-svg-NDKNkiLggZDPn6aZ .root .anchor path{fill:#333333!important;stroke-width:0;stroke:#333333;}#mermaid-svg-NDKNkiLggZDPn6aZ .arrowheadPath{fill:#333333;}#mermaid-svg-NDKNkiLggZDPn6aZ .edgePath .path{stroke:#333333;stroke-width:2.0px;}#mermaid-svg-NDKNkiLggZDPn6aZ 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class=\"nodeLabel\"><\/p>\n<p>\u51fa\u95ee\u9898\u4e0d\u7559\u70c2\u644a<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u4e0d\u4e3a\u4e0d\u5fc5\u8981\u4ed8\u8d39<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6838\u5fc3\u4e3b\u9898<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span class=\"edgeLabel\"><\/span><\/p>\n<p>         <span style=\"color:#fff !important\" class=\"nodeLabel\"><\/p>\n<p>\u5b9e\u73b0\u5c42\u9762\u7684\u6743\u8861\u4e0e\u7ea6\u675f<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6761\u6b3e25\u9ad8\u6548swap<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6761\u6b3e26\u5ef6\u540e\u53d8\u91cf\u5b9a\u4e49<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6761\u6b3e27\u5c11\u505a\u8f6c\u578b<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6761\u6b3e30\u8c28\u614einline<\/p>\n<p><\/span><\/p>\n<p>         <span class=\"nodeLabel\"><\/p>\n<p>\u6761\u6b3e31\u964d\u4f4e\u7f16\u8bd1\u4f9d\u5b58<\/p>\n<p><\/span><\/p>\n<p>         <span style=\"color:#fff !important\" class=\"nodeLabel\"><\/p>\n<p>\u6761\u6b3e28\u4e0d\u8fd4\u56de\u5185\u90e8handle<\/p>\n<p><\/span><\/p>\n<p>         <span style=\"color:#fff !important\" 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\/>\n<h2>&#x1f4da; \u53c2\u8003\u8d44\u6599<\/h2>\n<ul>\n<li>Scott Meyers\u300aEffective C&#043;&#043;&#xff08;\u7b2c\u4e09\u7248&#xff09;\u300b\u7b2c\u4e94\u7ae0&#xff1a;Implementations&#xff08;\u6761\u6b3e25-31&#xff09;<\/li>\n<li>Herb Sutter\u300aExceptional C&#043;&#043;\u300b\u6761\u6b3e8-19\u3001\u300aMore Exceptional C&#043;&#043;\u300b\u6761\u6b3e17-23&#xff08;\u5f02\u5e38\u5b89\u5168&#xff09;<\/li>\n<li>cppreference.com&#xff1a;Copy elision\u3001Return value optimization\u3001Exceptions<\/li>\n<li>C&#043;&#043; Core Guidelines&#xff1a;E.3-E.8&#xff08;\u5f02\u5e38\u5b89\u5168&#xff09;\u3001F.15-F.20&#xff08;\u53c2\u6570\u4f20\u9012&#xff09;\u3001I.27&#xff08;pimpl&#xff09;<\/li>\n<li>C&#043;&#043;20 Modules \u6807\u51c6\u63d0\u6848 P1103R3<\/li>\n<\/ul>\n<hr \/>\n<h2>&#x1f3f7;\ufe0f \u63a8\u8350\u6807\u7b7e<\/h2>\n<p>C&#043;&#043; Effective-C&#043;&#043; \u5f02\u5e38\u5b89\u5168 inline pimpl swap \u7c7b\u578b\u8f6c\u6362 \u7f16\u8bd1\u4f9d\u5b58 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