{"id":2107,"date":"2025-03-24T08:48:17","date_gmt":"2025-03-23T23:48:17","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=2107"},"modified":"2025-03-24T08:48:44","modified_gmt":"2025-03-23T23:48:44","slug":"%e5%ae%8c%e5%85%a8%e8%a7%a3%e8%aa%ac%ef%bc%81c-%e3%82%aa%e3%83%97%e3%82%b7%e3%83%a7%e3%83%b3%e3%81%a7%e5%ae%9f%e7%8f%be%e3%81%99%e3%82%8b%e5%ae%89%e5%85%a8%e3%81%a7%e5%8a%b9%e7%8e%87%e7%9a%84","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=2107","title":{"rendered":"\u5b8c\u5168\u89e3\u8aac\uff01C++ \u30aa\u30d7\u30b7\u30e7\u30f3\u3067\u5b9f\u73fe\u3059\u308b\u5b89\u5168\u3067\u52b9\u7387\u7684\u306a\u30b3\u30fc\u30c9\u8a2d\u8a08 &#8211; \u73fe\u5834\u3067\u4f7f\u3048\u308b7\u3064\u306e\u5b9f\u8df5\u30c6\u30af\u30cb\u30c3\u30af"},"content":{"rendered":"\n<div class=\"toc\"><br \/>\n<b>Warning<\/b>:  Undefined array key \"is_admin\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>116<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_category_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>121<\/b><br \/>\n<br \/>\n<b>Warning<\/b>:  Undefined array key \"is_top\" in <b>\/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/sango-theme\/library\/gutenberg\/dist\/classes\/Toc.php<\/b> on line <b>128<\/b><br \/>\n    <div id=\"toc_container\" class=\"sgb-toc--bullets js-smooth-scroll\" data-dialog-title=\"\u76ee\u6b21\">\n      <p class=\"toc_title\">\u76ee\u6b21 <\/p>\n      <ul class=\"toc_list\">  <li class=\"first\">    <a href=\"#i-0\">C++ \u30aa\u30d7\u30b7\u30e7\u30f3\u3068\u306f\uff1f\u30e2\u30c0\u30f3 C++ \u304c\u63d0\u4f9b\u3059\u308b\u5b89\u5168\u6027\u306e\u65b0\u3057\u3044\u9078\u629e\u80a2<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-1\">\u5f93\u6765\u306e null \u30dd\u30a4\u30f3\u30c8\u304c\u62b1\u3048\u308b\u6a19\u6e96\u554f\u984c\u70b9\u3068\u89e3\u6c7a\u7b56\u3068\u3057\u3066\u306e std::optional<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-2\">\u5024\u306e\u5b58\u5728\u3092\u80af\u5b9a\u3059\u308b\u30b7\u30b9\u30c6\u30e0\u3067\u8868\u73fe\u3059\u308boptional\u306e\u57fa\u672c\u6982\u5ff5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-3\">std::optional\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-4\">\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u751f\u6210\u3068\u521d\u671f\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li>        <a href=\"#i-5\">has_value\u3068value\u95a2\u6570\u306b\u3088\u308b\u5b89\u5168\u306a\u5024\u30a2\u30af\u30bb\u30b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-6\">value_or\u95a2\u6570\u3067\u78ba\u5b9f\u306a\u5024\u3092\u6307\u5b9a\u3059\u308b\u65b9\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-7\">\u73fe\u5834\u3067\u6d3b\u304d\u308b\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u30d1\u30bf\u30fc\u30f3<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-8\">\u95a2\u6570\u306e\u623b\u308a\u5024\u3068\u3057\u3066\u30aa\u30d7\u30b7\u30e7\u30f3\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>      <\/li>      <li>        <a href=\"#i-9\">\u30af\u30e9\u30b9\u30e1\u30f3\u30d0\u3068\u3057\u3066\u306eoptional\u306e\u52b9\u679c\u7684\u306a\u6d3b\u7528\u65b9\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-10\">\u6761\u4ef6\u4ed8\u304d\u5024\u306e\u521d\u671f\u5316\u306b\u304a\u3051\u308boptional\u306e\u5a01\u529b<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-11\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30e1\u30e2\u30ea\u7ba1\u7406\u306e\u89b3\u70b9\u304b\u3089\u898b\u308boptional<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-12\">\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u30e1\u30e2\u30ea\u30ec\u30a4\u30a2\u30a6\u30c8\u3068\u6700\u9069\u5316\u306e\u30dd\u30a4\u30f3\u30c8<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-13\">\u53c2\u7167\u30e9\u30c3\u30d4\u30f3\u30b0\u3068\u30e0\u30fc\u30d6\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u306e\u6d3b\u7528<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-14\">\u30aa\u30d7\u30b7\u30e7\u30f3\u3092\u4f7f\u3063\u305f\u5b9f\u88c5\u4f8b\u3068\u8a2d\u8a08\u30d1\u30bf\u30fc\u30f3<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-15\">\u975e\u540c\u671f\u51e6\u7406\u306b\u304a\u3051\u308b\u623b\u308a\u5024\u3068\u3057\u3066\u306eoptional\u306e\u6d3b\u7528<\/a>      <\/li>      <li>        <a href=\"#i-16\">\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u6a5f\u80fd\u306e\u5b9f\u88c5\u306b\u304a\u3051\u308boptional\u306e\u4f7f\u7528<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-17\">\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u9045\u5ef6\u521d\u671f\u5316\u30d1\u30bf\u30fc\u30f3\u306e\u5b9f\u73fe<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-18\">\u30aa\u30d7\u30b7\u30e7\u30f3\u306b\u95a2\u3059\u308b\u6ce8\u610f\u70b9\u3068\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-19\">\u4f8b\u5916\u51e6\u7406\u3068\u306e\u30ac\u30a4\u30c9\u30e9\u30a4\u30f3<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-20\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u5f71\u97ff\u3092\u8003\u616e\u3057\u305f\u9069\u5207\u306a\u4f7f\u7528\u5834\u9762<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-21\">\u3088\u308a\u6df1\u3044\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u7406\u89e3\u306e\u305f\u3081\u306b<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-22\">C++17 \u4ee5\u964d\u306e\u65b0\u6a5f\u80fd\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\u6d3b\u7528\u6cd5<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-23\">\u4ed6\u8a00\u8a9e\u306b\u304a\u3051\u308b\u540c\u69d8\u306e\u6a5f\u80fd\u3068\u306e\u6bd4\u8f03<\/a>      <\/li>    <\/ul>  <\/li><\/ul>\n      <a href=\"#\" class=\"sgb-toc-button js-toc-button\" rel=\"nofollow\" data-open-dialog=\"true\"><i class=\"fa fa-list\"><\/i><span class=\"sgb-toc-button__text\">\u76ee\u6b21\u3078<\/span><\/a>\n    <\/div><\/div><h2 class=\"wp-block-heading\" id=\"i-0\">C++ \u30aa\u30d7\u30b7\u30e7\u30f3\u3068\u306f\uff1f\u30e2\u30c0\u30f3 C++ \u304c\u63d0\u4f9b\u3059\u308b\u5b89\u5168\u6027\u306e\u65b0\u3057\u3044\u9078\u629e\u80a2<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-1\">\u5f93\u6765\u306e null \u30dd\u30a4\u30f3\u30c8\u304c\u62b1\u3048\u308b\u6a19\u6e96\u554f\u984c\u70b9\u3068\u89e3\u6c7a\u7b56\u3068\u3057\u3066\u306e std::optional<\/h3>\n\n\n\n<p>C++\u958b\u767a\u306b\u304a\u3044\u3066\u3001\u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u53ef\u80fd\u6027\u3092\u8868\u73fe\u3059\u308b\u65b9\u6cd5\u3068\u3057\u3066\u9577\u5e74\u4f7f\u7528\u3055\u308c\u3066\u304d\u305f\u306e\u304c\u300cnull\u30dd\u30a4\u30f3\u30bf\u300d\u3067\u3059\u3002\u3057\u304b\u3057\u3001\u3053\u306e\u30a2\u30d7\u30ed\u30fc\u30c1\u306b\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u91cd\u5927\u306a\u554f\u984c\u304c\u5b58\u5728\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u672a\u5b9a\u7fa9\u52d5\u4f5c\u306e\u5371\u967a\u6027<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>null\u30dd\u30a4\u30f3\u30bf\u306e\u53c2\u7167\u306b\u3088\u308b\u672a\u5b9a\u7fa9\u52d5\u4f5c<\/li>\n\n\n\n<li>\u30bb\u30b0\u30e1\u30f3\u30c6\u30fc\u30b7\u30e7\u30f3\u9055\u53cd\u306b\u3088\u308b\u30d7\u30ed\u30b0\u30e9\u30e0\u306e\u30af\u30e9\u30c3\u30b7\u30e5<\/li>\n\n\n\n<li>\u30c7\u30d0\u30c3\u30b0\u306e\u56f0\u96e3\u3055<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u610f\u56f3\u306e\u4e0d\u660e\u78ba\u3055<\/strong><\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   \/\/ null\u30dd\u30a4\u30f3\u30bf\u3092\u4f7f\u7528\u3057\u305f\u5f93\u6765\u306e\u5b9f\u88c5\n   User* findUser(const std::string&amp; id) {\n       \/\/ \u30e6\u30fc\u30b6\u30fc\u304c\u898b\u3064\u304b\u3089\u306a\u3044\u5834\u5408\u306fnull\u3092\u8fd4\u3059\n       \/\/ \u203b\u3053\u306e\u95a2\u6570\u304c\u6240\u6709\u6a29\u3092\u79fb\u8ee2\u3059\u308b\u306e\u304b\u3001\u5358\u306a\u308b\u53c2\u7167\u306a\u306e\u304b\u304c\u4e0d\u660e\u78ba\n       return nullptr;\n   }<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u554f\u984c\u306b\u5bfe\u3059\u308b\u89e3\u6c7a\u7b56\u3068\u3057\u3066\u3001C++17\u3067\u5c0e\u5165\u3055\u308c\u305f<code>std::optional<\/code>\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u5229\u70b9\u3092\u63d0\u4f9b\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ std::optional\u3092\u4f7f\u7528\u3057\u305f\u5b89\u5168\u306a\u5b9f\u88c5\nstd::optional&lt;User&gt; findUser(const std::string&amp; id) {\n    if (userExists(id)) {\n        return User(id);  \/\/ \u5024\u304c\u5b58\u5728\u3059\u308b\u5834\u5408\n    }\n    return std::nullopt;  \/\/ \u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-2\">\u5024\u306e\u5b58\u5728\u3092\u80af\u5b9a\u3059\u308b\u30b7\u30b9\u30c6\u30e0\u3067\u8868\u73fe\u3059\u308boptional\u306e\u57fa\u672c\u6982\u5ff5<\/h3>\n\n\n\n<p><code>std::optional<\/code>\u306f\u300c\u5024\u304c\u5b58\u5728\u3059\u308b\u304b\u3082\u3057\u308c\u306a\u3044\u3057\u3001\u3057\u306a\u3044\u304b\u3082\u3057\u308c\u306a\u3044\u300d\u3068\u3044\u3046\u72b6\u614b\u3092\u578b\u5b89\u5168\u306b\u8868\u73fe\u3059\u308b\u305f\u3081\u306e\u30e9\u30c3\u30d1\u30fc\u30af\u30e9\u30b9\u3067\u3059\u3002\u4ee5\u4e0b\u306e\u7279\u5fb4\u3092\u6301\u3061\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u578b\u5b89\u5168\u6027\u306e\u4fdd\u8a3c<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b3\u30f3\u30d1\u30a4\u30eb\u6642\u306e\u578b\u30c1\u30a7\u30c3\u30af<\/li>\n\n\n\n<li>\u660e\u793a\u7684\u306a\u5024\u306e\u6709\u7121\u306e\u78ba\u8a8d\u304c\u5fc5\u8981<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u4fa1\u5024\u306e\u660e\u78ba\u306a\u8868\u73fe<\/strong><\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   std::optional&lt;int&gt; parseNumber(const std::string&amp; str) {\n       try {\n           return std::stoi(str);  \/\/ \u6570\u5024\u5909\u63db\u304c\u6210\u529f\u3057\u305f\u5834\u5408\n       } catch (...) {\n           return std::nullopt;    \/\/ \u5909\u63db\u5931\u6557\u6642\n       }\n   }<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li><strong>\u30e2\u30c0\u30f3C++\u306e\u6a5f\u80fd\u3068\u306e\u7d71\u5408<\/strong><\/li>\n<\/ol>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">   \/\/ \u69cb\u9020\u5316\u675f\u7e1b\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\n   if (auto result = parseNumber(\"123\"); result.has_value()) {\n       int value = *result;  \/\/ \u5b89\u5168\u306a\u5024\u306e\u53d6\u5f97\n       \/\/ value\u306e\u4f7f\u7528\n   }<\/pre>\n\n\n\n<ol start=\"4\" class=\"wp-block-list\">\n<li><strong>\u5024\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u306e\u30b5\u30dd\u30fc\u30c8<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b3\u30d4\u30fc\/\u30e0\u30fc\u30d6\u306e\u660e\u78ba\u306a\u52d5\u4f5c<\/li>\n\n\n\n<li>\u30ea\u30bd\u30fc\u30b9\u7ba1\u7406\u306e\u7c21\u7d20\u5316<\/li>\n<\/ul>\n\n\n\n<p><code>std::optional<\/code>\u306e\u5c0e\u5165\u306b\u3088\u308a\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u958b\u767a\u4e0a\u306e\u5229\u70b9\u304c\u5f97\u3089\u308c\u307e\u3059\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b3\u30fc\u30c9\u306e\u610f\u56f3\u304c\u660e\u78ba\u306b\u306a\u308b<\/li>\n\n\n\n<li>\u5b9f\u884c\u6642\u306e\u5b89\u5168\u6027\u304c\u5411\u4e0a<\/li>\n\n\n\n<li>\u30e1\u30f3\u30c6\u30ca\u30f3\u30b9\u6027\u306e\u6539\u5584<\/li>\n\n\n\n<li>\u30d0\u30b0\u306e\u65e9\u671f\u767a\u898b<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u306e\u3088\u3046\u306b\u3001<code>std::optional<\/code>\u306f\u5358\u306a\u308bnull\u30dd\u30a4\u30f3\u30bf\u306e\u4ee3\u66ff\u3068\u3044\u3046\u3060\u3051\u3067\u306a\u304f\u3001\u30e2\u30c0\u30f3C++\u306b\u304a\u3051\u308b\u5024\u306e\u4e0d\u78ba\u5b9f\u6027\u3092\u8868\u73fe\u3059\u308b\u305f\u3081\u306e\u5f37\u529b\u306a\u30c4\u30fc\u30eb\u3068\u3057\u3066\u6a5f\u80fd\u3057\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u306e\u6a5f\u80fd\u306e\u5177\u4f53\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u898b\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-3\">std::optional\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-4\">\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u751f\u6210\u3068\u521d\u671f\u5316\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n\n\n\n<p>std::optional\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u751f\u6210\u3068\u521d\u671f\u5316\u306b\u306f\u3001\u8907\u6570\u306e\u65b9\u6cd5\u304c\u7528\u610f\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u4ee5\u4e0b\u306b\u4e3b\u8981\u306a\u521d\u671f\u5316\u30d1\u30bf\u30fc\u30f3\u3092\u793a\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#include &lt;optional&gt;\n#include &lt;string&gt;\n\n\/\/ 1. \u30c7\u30d5\u30a9\u30eb\u30c8\u69cb\u7bc9\uff08\u7a7a\u306eoptional\uff09\nstd::optional&lt;int&gt; opt1;  \/\/ \u5024\u306a\u3057\n\n\/\/ 2. nullopt\u306b\u3088\u308b\u660e\u793a\u7684\u306a\u7a7a\u306e\u521d\u671f\u5316\nstd::optional&lt;std::string&gt; opt2 = std::nullopt;\n\n\/\/ 3. \u5024\u3092\u6301\u3064optional\u306e\u4f5c\u6210\nstd::optional&lt;int&gt; opt3 = 42;  \/\/ \u76f4\u63a5\u521d\u671f\u5316\nstd::optional&lt;std::string&gt; opt4{\"Hello\"};  \/\/ \u6587\u5b57\u5217\u3067\u521d\u671f\u5316\n\n\/\/ 4. \u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u5f15\u6570\u3092\u6e21\u3057\u3066\u521d\u671f\u5316\nstd::optional&lt;std::string&gt; opt5{std::in_place, 5, 'x'};  \/\/ \"xxxxx\"\u3067\u521d\u671f\u5316\n\n\/\/ 5. \u4ed6\u306eoptional\u304b\u3089\u306e\u30b3\u30d4\u30fc\/\u30e0\u30fc\u30d6\nstd::optional&lt;int&gt; opt6 = opt3;  \/\/ \u30b3\u30d4\u30fc\u69cb\u7bc9<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-5\">has_value\u3068value\u95a2\u6570\u306b\u3088\u308b\u5b89\u5168\u306a\u5024\u30a2\u30af\u30bb\u30b9<\/h3>\n\n\n\n<p>std::optional\u306e\u5024\u3078\u306e\u30a2\u30af\u30bb\u30b9\u306f\u3001\u5fc5\u305a\u5024\u306e\u5b58\u5728\u78ba\u8a8d\u3068\u7d44\u307f\u5408\u308f\u305b\u3066\u884c\u3046\u5fc5\u8981\u304c\u3042\u308a\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">std::optional&lt;int&gt; getValue() {\n    \/\/ \u4f55\u3089\u304b\u306e\u51e6\u7406\u3067\u5024\u3092\u53d6\u5f97\n    return 42;\n}\n\nvoid demonstrateAccess() {\n    auto opt = getValue();\n\n    \/\/ 1. has_value()\u306b\u3088\u308b\u5b58\u5728\u78ba\u8a8d\n    if (opt.has_value()) {\n        \/\/ value()\u3067\u5024\u306b\u30a2\u30af\u30bb\u30b9\n        int val = opt.value();\n        \/\/ \u51e6\u7406...\n    }\n\n    \/\/ 2. bool\u6f14\u7b97\u5b50\u306b\u3088\u308b\u78ba\u8a8d\n    if (opt) {\n        \/\/ \u6f14\u7b97\u5b50*\u306b\u3088\u308b\u5024\u30a2\u30af\u30bb\u30b9\n        int val = *opt;\n        \/\/ \u51e6\u7406...\n    }\n\n    try {\n        \/\/ 3. \u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306f\u4f8b\u5916\u3092\u30b9\u30ed\u30fc\n        int val = opt.value();\n    } catch (const std::bad_optional_access&amp; e) {\n        \/\/ \u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306e\u4f8b\u5916\u51e6\u7406\n        std::cerr &lt;&lt; \"\u5024\u304c\u5b58\u5728\u3057\u307e\u305b\u3093: \" &lt;&lt; e.what() &lt;&lt; std::endl;\n    }\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-6\">value_or\u95a2\u6570\u3067\u78ba\u5b9f\u306a\u5024\u3092\u6307\u5b9a\u3059\u308b\u65b9\u6cd5<\/h3>\n\n\n\n<p>value_or()\u30e1\u30bd\u30c3\u30c9\u306f\u3001\u5024\u304c\u5b58\u5728\u3057\u306a\u3044\u5834\u5408\u306e\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3092\u6307\u5b9a\u3067\u304d\u308b\u4fbf\u5229\u306a\u6a5f\u80fd\u3067\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Configuration {\npublic:\n    std::optional&lt;int&gt; getTimeout() const {\n        \/\/ \u8a2d\u5b9a\u304b\u3089\u5024\u3092\u53d6\u5f97\n        return std::nullopt;  \/\/ \u5024\u304c\u8a2d\u5b9a\u3055\u308c\u3066\u3044\u306a\u3044\u5834\u5408\n    }\n};\n\nvoid demonstrateValueOr() {\n    Configuration config;\n\n    \/\/ 1. \u57fa\u672c\u7684\u306avalue_or\u306e\u4f7f\u7528\n    int timeout = config.getTimeout().value_or(30);  \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3068\u3057\u306630\u3092\u4f7f\u7528\n\n    \/\/ 2. \u8a08\u7b97\u3055\u308c\u305f\u5024\u3092\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3068\u3057\u3066\u4f7f\u7528\n    std::optional&lt;std::string&gt; name;\n    std::string displayName = name.value_or(\"Guest-\" + std::to_string(rand()));\n\n    \/\/ 3. \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305fvalue_or\u306e\u4f7f\u7528\n    std::optional&lt;std::string&gt; heavyString;\n    std::string result = heavyString.value_or(calculateDefaultValue());  \/\/ \u5fc5\u8981\u306a\u5834\u5408\u306e\u307f\u8a08\u7b97\n}\n\n\/\/ value_or\u3092\u4f7f\u7528\u3057\u305f\u5b9f\u8df5\u7684\u306a\u4f8b\nclass UserSettings {\nprivate:\n    std::optional&lt;int&gt; fontSize;\n    std::optional&lt;std::string&gt; theme;\n\npublic:\n    int getFontSize() const {\n        return fontSize.value_or(12);  \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u306e\u30d5\u30a9\u30f3\u30c8\u30b5\u30a4\u30ba\u306f12\n    }\n\n    std::string getTheme() const {\n        return theme.value_or(\"default\");  \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u306e\u30c6\u30fc\u30de\n    }\n};<\/pre>\n\n\n\n<p>std::optional\u306e\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u305f\u3081\u306e\u30dd\u30a4\u30f3\u30c8\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u521d\u671f\u5316\u306e\u9078\u629e<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u7528\u9014\u306b\u5fdc\u3058\u3066\u9069\u5207\u306a\u521d\u671f\u5316\u65b9\u6cd5\u3092\u9078\u629e<\/li>\n\n\n\n<li>in_place\u3092\u6d3b\u7528\u3057\u3066\u7121\u99c4\u306a\u30b3\u30d4\u30fc\u3092\u907f\u3051\u308b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u5b89\u5168\u306a\u30a2\u30af\u30bb\u30b9<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5fc5\u305a\u5024\u306e\u5b58\u5728\u78ba\u8a8d\u3092\u884c\u3046<\/li>\n\n\n\n<li>\u4f8b\u5916\u51e6\u7406\u3092\u9069\u5207\u306b\u5b9f\u88c5<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u63d0\u4f9b<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>value_or()\u3092\u6d3b\u7528\u3057\u3066\u5b89\u5168\u306a\u30d5\u30a9\u30fc\u30eb\u30d0\u30c3\u30af\u3092\u5b9f\u88c5<\/li>\n\n\n\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u8a08\u7b97<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u57fa\u672c\u7684\u306a\u64cd\u4f5c\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u3053\u3068\u3067\u3001std::optional\u3092\u52b9\u679c\u7684\u306b\u6d3b\u7528\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3088\u308a\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u30d1\u30bf\u30fc\u30f3\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-7\">\u73fe\u5834\u3067\u6d3b\u304d\u308b\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u30d1\u30bf\u30fc\u30f3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-8\">\u95a2\u6570\u306e\u623b\u308a\u5024\u3068\u3057\u3066\u30aa\u30d7\u30b7\u30e7\u30f3\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h3>\n\n\n\n<p>\u95a2\u6570\u306e\u623b\u308a\u5024\u3068\u3057\u3066<code>std::optional<\/code>\u3092\u4f7f\u7528\u3059\u308b\u5834\u5408\u306e\u52b9\u679c\u7684\u306a\u30d1\u30bf\u30fc\u30f3\u3092\u7d39\u4ecb\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class UserRepository {\npublic:\n    \/\/ 1. \u691c\u7d22\u7cfb\u306e\u95a2\u6570\u3067\u306e\u4f7f\u7528\n    std::optional&lt;User&gt; findById(int userId) {\n        auto user = database.query(userId);\n        if (user.exists()) {\n            return User(user.data());\n        }\n        return std::nullopt;\n    }\n\n    \/\/ 2. \u5909\u63db\u51e6\u7406\u3067\u306e\u4f7f\u7528\n    std::optional&lt;int&gt; parseUserId(const std::string&amp; input) {\n        try {\n            int id = std::stoi(input);\n            if (id &gt; 0) {  \/\/ \u696d\u52d9\u30eb\u30fc\u30eb\u306e\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\n                return id;\n            }\n        } catch (...) {\n            \/\/ \u5909\u63db\u5931\u6557\u306f\u9759\u304b\u306b\u51e6\u7406\n        }\n        return std::nullopt;\n    }\n\n    \/\/ 3. \u30c1\u30a7\u30fc\u30f3\u51e6\u7406\u3067\u306e\u6d3b\u7528\n    std::optional&lt;UserProfile&gt; findProfileByEmail(const std::string&amp; email) {\n        return findUserByEmail(email)\n            .and_then(&amp;User::getProfile);  \/\/ C++23\u306e\u6a5f\u80fd\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-9\">\u30af\u30e9\u30b9\u30e1\u30f3\u30d0\u3068\u3057\u3066\u306eoptional\u306e\u52b9\u679c\u7684\u306a\u6d3b\u7528\u65b9\u6cd5<\/h3>\n\n\n\n<p>\u30af\u30e9\u30b9\u8a2d\u8a08\u306b\u304a\u3051\u308b<code>std::optional<\/code>\u306e\u6226\u7565\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\u3092\u793a\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Document {\nprivate:\n    std::string title;\n    std::optional&lt;std::string&gt; subtitle;  \/\/ \u30aa\u30d7\u30b7\u30e7\u30ca\u30eb\u306a\u526f\u984c\n    std::optional&lt;std::chrono::system_clock::time_point&gt; lastModified;\n    std::optional&lt;User&gt; lastEditor;\n\npublic:\n    \/\/ 1. \u30d3\u30eb\u30c0\u30fc\u30d1\u30bf\u30fc\u30f3\u3067\u306e\u6d3b\u7528\n    class Builder {\n    private:\n        Document doc;\n    public:\n        Builder&amp; setSubtitle(const std::string&amp; subtitle) {\n            doc.subtitle = subtitle;\n            return *this;\n        }\n        Builder&amp; setLastModified(const std::chrono::system_clock::time_point&amp; time) {\n            doc.lastModified = time;\n            return *this;\n        }\n        Document build() {\n            return std::move(doc);\n        }\n    };\n\n    \/\/ 2. \u30aa\u30d7\u30b7\u30e7\u30ca\u30eb\u30d5\u30a3\u30fc\u30eb\u30c9\u306e\u30a2\u30af\u30bb\u30b5\n    const std::optional&lt;std::string&gt;&amp; getSubtitle() const { return subtitle; }\n    void setSubtitle(std::optional&lt;std::string&gt; newSubtitle) {\n        subtitle = std::move(newSubtitle);\n    }\n\n    \/\/ 3. \u30aa\u30d7\u30b7\u30e7\u30ca\u30eb\u30d5\u30a3\u30fc\u30eb\u30c9\u3092\u8003\u616e\u3057\u305f\u7b49\u4fa1\u6027\u306e\u5b9f\u88c5\n    bool operator==(const Document&amp; other) const {\n        return title == other.title &amp;&amp;\n               subtitle == other.subtitle &amp;&amp;\n               lastModified == other.lastModified &amp;&amp;\n               lastEditor == other.lastEditor;\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-10\">\u6761\u4ef6\u4ed8\u304d\u5024\u306e\u521d\u671f\u5316\u306b\u304a\u3051\u308boptional\u306e\u5a01\u529b<\/h3>\n\n\n\n<p>\u6761\u4ef6\u306b\u57fa\u3065\u304f\u521d\u671f\u5316\u3068\u30c7\u30fc\u30bf\u5909\u63db\u3067\u306e<code>std::optional<\/code>\u306e\u6d3b\u7528\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ConfigurationManager {\npublic:\n    \/\/ 1. \u6761\u4ef6\u4ed8\u304d\u521d\u671f\u5316\u30d1\u30bf\u30fc\u30f3\n    std::optional&lt;DatabaseConnection&gt; initializeDatabase(const Config&amp; config) {\n        if (!config.hasValidDbSettings()) {\n            return std::nullopt;\n        }\n\n        try {\n            return DatabaseConnection(\n                config.getHost(),\n                config.getPort(),\n                config.getCredentials()\n            );\n        } catch (const ConnectionError&amp;) {\n            return std::nullopt;\n        }\n    }\n\n    \/\/ 2. \u8907\u6570\u6761\u4ef6\u306e\u7d44\u307f\u5408\u308f\u305b\n    std::optional&lt;Report&gt; generateReport(\n        const std::optional&lt;User&gt;&amp; user,\n        const std::optional&lt;TimeRange&gt;&amp; timeRange) {\n\n        \/\/ \u4e21\u65b9\u306e\u5024\u304c\u5b58\u5728\u3059\u308b\u5834\u5408\u306e\u307f\u30ec\u30dd\u30fc\u30c8\u751f\u6210\n        if (user &amp;&amp; timeRange) {\n            return Report::create(*user, *timeRange);\n        }\n        return std::nullopt;\n    }\n\n    \/\/ 3. \u6761\u4ef6\u4ed8\u304d\u30c7\u30fc\u30bf\u5909\u63db\n    template&lt;typename T&gt;\n    std::optional&lt;std::string&gt; serializeIfValid(const T&amp; value) {\n        if (!value.isValid()) {\n            return std::nullopt;\n        }\n        return value.serialize();\n    }\n};\n\n\/\/ \u5b9f\u8df5\u7684\u306a\u4f7f\u7528\u4f8b\uff1a\u30d5\u30a9\u30fc\u30e0\u5165\u529b\u306e\u691c\u8a3c\nclass FormValidator {\npublic:\n    static std::optional&lt;EmailAddress&gt; validateEmail(const std::string&amp; input) {\n        if (!isValidEmailFormat(input)) {\n            return std::nullopt;\n        }\n        return EmailAddress(input);\n    }\n\n    static std::optional&lt;PhoneNumber&gt; validatePhone(const std::string&amp; input) {\n        if (!isValidPhoneFormat(input)) {\n            return std::nullopt;\n        }\n        return PhoneNumber(input);\n    }\n\n    \/\/ \u8907\u6570\u306e\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u4f8b\n    static std::optional&lt;UserContact&gt; validateContactInfo(\n        const std::string&amp; email,\n        const std::string&amp; phone) {\n\n        auto validEmail = validateEmail(email);\n        auto validPhone = validatePhone(phone);\n\n        if (validEmail &amp;&amp; validPhone) {\n            return UserContact{*validEmail, *validPhone};\n        }\n        return std::nullopt;\n    }\n};<\/pre>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30d1\u30bf\u30fc\u30f3\u3092\u6d3b\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u5229\u70b9\u304c\u5f97\u3089\u308c\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30b3\u30fc\u30c9\u306e\u610f\u56f3\u306e\u660e\u78ba\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5024\u306e\u5b58\u5728\u53ef\u80fd\u6027\u304c\u578b\u30ec\u30d9\u30eb\u3067\u8868\u73fe\u3055\u308c\u308b<\/li>\n\n\n\n<li>API\u5951\u7d04\u304c\u660e\u78ba\u306b\u306a\u308b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u7c21\u7d20\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f8b\u5916\u306b\u983c\u3089\u306a\u3044\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u5b9f\u73fe<\/li>\n\n\n\n<li>\u6761\u4ef6\u5206\u5c90\u306e\u53ef\u8aad\u6027\u5411\u4e0a<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u4fdd\u5b88\u6027\u306e\u5411\u4e0a<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30aa\u30d7\u30b7\u30e7\u30ca\u30eb\u306a\u8981\u7d20\u306e\u8ffd\u52a0\/\u524a\u9664\u304c\u5bb9\u6613<\/li>\n\n\n\n<li>\u578b\u5b89\u5168\u6027\u306b\u3088\u308b\u5909\u66f4\u306e\u5f71\u97ff\u7bc4\u56f2\u306e\u5236\u5fa1<\/li>\n<\/ul>\n\n\n\n<p>\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u30d1\u30bf\u30fc\u30f3\u3092\u5b9f\u88c5\u3059\u308b\u969b\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30e1\u30e2\u30ea\u7ba1\u7406\u306e\u8003\u616e\u70b9\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-11\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30e1\u30e2\u30ea\u7ba1\u7406\u306e\u89b3\u70b9\u304b\u3089\u898b\u308boptional<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-12\">\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u30e1\u30e2\u30ea\u30ec\u30a4\u30a2\u30a6\u30c8\u3068\u6700\u9069\u5316\u306e\u30dd\u30a4\u30f3\u30c8<\/h3>\n\n\n\n<p>std::optional\u306e\u30e1\u30e2\u30ea\u30ec\u30a4\u30a2\u30a6\u30c8\u3068\u5185\u90e8\u5b9f\u88c5\u306b\u3064\u3044\u3066\u7406\u89e3\u3059\u308b\u3053\u3068\u306f\u3001\u52b9\u7387\u7684\u306a\u4f7f\u7528\u306e\u305f\u3081\u306b\u91cd\u8981\u3067\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#include &lt;optional&gt;\n#include &lt;cassert&gt;\n#include &lt;string&gt;\n\n\/\/ \u30e1\u30e2\u30ea\u30ec\u30a4\u30a2\u30a6\u30c8\u306e\u691c\u8a3c\nvoid examineOptionalLayout() {\n    \/\/ 1. \u57fa\u672c\u578b\u306eoptional\u306e\u30b5\u30a4\u30ba\n    static_assert(sizeof(std::optional&lt;bool&gt;) &gt; sizeof(bool),\n        \"optional&lt;bool&gt;\u306f\u72b6\u614b\u7ba1\u7406\u306e\u305f\u3081\u306e\u8ffd\u52a0\u9818\u57df\u304c\u5fc5\u8981\");\n\n    \/\/ 2. \u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u306e\u8003\u616e\n    struct alignas(8) AlignedType {\n        int x;  \/\/ 4\u30d0\u30a4\u30c8\n    };\n\n    static_assert(alignof(std::optional&lt;AlignedType&gt;) &gt;= alignof(AlignedType),\n        \"optional\u306f\u5143\u306e\u578b\u306e\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u8981\u4ef6\u3092\u7dad\u6301\u3059\u308b\");\n}\n\n\/\/ \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u30c6\u30af\u30cb\u30c3\u30af\nclass OptimizedStorage {\nprivate:\n    \/\/ \u5927\u304d\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u30dd\u30a4\u30f3\u30bf\u3068\u3057\u3066\u4fdd\u6301\n    std::optional&lt;std::string&gt; lightWeight;      \/\/ \u76f4\u63a5\u4fdd\u6301\n    std::optional&lt;std::reference_wrapper&lt;std::vector&lt;int&gt;&gt;&gt; heavyWeight;  \/\/ \u53c2\u7167\u3068\u3057\u3066\u4fdd\u6301\n\npublic:\n    \/\/ 3. \u30b3\u30d4\u30fc\/\u30e0\u30fc\u30d6\u30b3\u30b9\u30c8\u306e\u6700\u9069\u5316\n    void optimizeMove(std::optional&lt;std::string&gt;&amp;&amp; str) {\n        lightWeight = std::move(str);  \/\/ \u30e0\u30fc\u30d6\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u6d3b\u7528\n    }\n\n    \/\/ 4. \u4e0d\u8981\u306a\u30b3\u30d4\u30fc\u306e\u56de\u907f\n    template&lt;typename... Args&gt;\n    void emplaceConstruct(Args&amp;&amp;... args) {\n        lightWeight.emplace(std::forward&lt;Args&gt;(args)...);  \/\/ \u76f4\u63a5\u69cb\u7bc9\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-13\">\u53c2\u7167\u30e9\u30c3\u30d4\u30f3\u30b0\u3068\u30e0\u30fc\u30d6\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u306e\u6d3b\u7528<\/h3>\n\n\n\n<p>\u52b9\u7387\u7684\u306a\u30e1\u30e2\u30ea\u4f7f\u7528\u3068\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u305f\u3081\u306e\u6226\u7565\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#include &lt;functional&gt;\n#include &lt;memory&gt;\n\nclass ResourceManager {\npublic:\n    \/\/ 1. \u53c2\u7167\u30e9\u30c3\u30d4\u30f3\u30b0\u306b\u3088\u308b\u30e1\u30e2\u30ea\u6700\u9069\u5316\n    std::optional&lt;std::reference_wrapper&lt;const BigResource&gt;&gt; \n    findResource(const std::string&amp; id) const {\n        if (auto it = resources.find(id); it != resources.end()) {\n            return std::cref(it-&gt;second);\n        }\n        return std::nullopt;\n    }\n\n    \/\/ 2. \u30e0\u30fc\u30d6\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9\u306e\u6d3b\u7528\n    class UniqueResource {\n    private:\n        std::unique_ptr&lt;Resource&gt; ptr;\n    public:\n        std::optional&lt;UniqueResource&gt; clone() const {\n            if (!ptr) return std::nullopt;\n            return UniqueResource{std::make_unique&lt;Resource&gt;(*ptr)};\n        }\n    };\n\n    \/\/ 3. \u6700\u9069\u5316\u3055\u308c\u305f\u30c7\u30fc\u30bf\u69cb\u9020\n    template&lt;typename T&gt;\n    class OptimizedContainer {\n    private:\n        std::optional&lt;T&gt; cached_value;\n    public:\n        \/\/ \u5024\u306e\u9045\u5ef6\u8a08\u7b97\n        const T&amp; getValue() {\n            if (!cached_value) {\n                cached_value = calculateExpensiveValue();\n            }\n            return *cached_value;\n        }\n\n        \/\/ \u30ad\u30e3\u30c3\u30b7\u30e5\u306e\u30af\u30ea\u30a2\n        void invalidateCache() {\n            cached_value.reset();\n        }\n    };\n};\n\n\/\/ \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u305f\u3081\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\nclass PerformanceOptimization {\npublic:\n    \/\/ 1. \u5c0f\u3055\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u76f4\u63a5\u4fdd\u6301\n    std::optional&lt;SmallObject&gt; small;  \/\/ \u30b3\u30d4\u30fc\/\u30e0\u30fc\u30d6\u304c\u5b89\u4fa1\n\n    \/\/ 2. \u5927\u304d\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u53c2\u7167\u4fdd\u6301\n    std::optional&lt;std::reference_wrapper&lt;BigObject&gt;&gt; big;  \/\/ \u53c2\u7167\u3067\u8efd\u91cf\u5316\n\n    \/\/ 3. \u6761\u4ef6\u4ed8\u304d\u521d\u671f\u5316\u306e\u6700\u9069\u5316\n    template&lt;typename T&gt;\n    std::optional&lt;T&gt; initializeIfNeeded(bool condition) {\n        if (!condition) return std::nullopt;\n        \/\/ \u6761\u4ef6\u3092\u6e80\u305f\u3059\u5834\u5408\u306e\u307f\u69cb\u7bc9\n        return std::optional&lt;T&gt;(std::in_place, \/* \u521d\u671f\u5316\u30d1\u30e9\u30e1\u30fc\u30bf *\/);\n    }\n};<\/pre>\n\n\n\n<p>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\u306e\u305f\u3081\u306e\u91cd\u8981\u306a\u30dd\u30a4\u30f3\u30c8\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30e1\u30e2\u30ea\u30ec\u30a4\u30a2\u30a6\u30c8\u306e\u8003\u616e<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u30b5\u30a4\u30ba\u3068\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u306e\u628a\u63e1<\/li>\n\n\n\n<li>\u30ad\u30e3\u30c3\u30b7\u30e5\u30e9\u30a4\u30f3\u3078\u306e\u5f71\u97ff\u3092\u8003\u616e<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30b3\u30d4\u30fc\/\u30e0\u30fc\u30d6\u306e\u6700\u9069\u5316<\/strong> \u64cd\u4f5c \u30b3\u30b9\u30c8 \u63a8\u5968\u3055\u308c\u308b\u4f7f\u7528\u5834\u9762 \u30b3\u30d4\u30fc \u9ad8 \u5c0f\u3055\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8 \u30e0\u30fc\u30d6 \u4e2d \u6240\u6709\u6a29\u306e\u79fb\u8ee2\u304c\u5fc5\u8981\u306a\u5834\u5408 \u53c2\u7167 \u4f4e \u5927\u304d\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8<\/li>\n\n\n\n<li><strong>\u30e1\u30e2\u30ea\u4f7f\u7528\u91cf\u306e\u6700\u9069\u5316<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5fc5\u8981\u306b\u5fdc\u3058\u305f\u53c2\u7167\u30e9\u30c3\u30d4\u30f3\u30b0<\/li>\n\n\n\n<li>\u9069\u5207\u306a\u30b5\u30a4\u30ba\u306e\u30d0\u30c3\u30d5\u30a1\u7ba1\u7406<\/li>\n\n\n\n<li>\u30b9\u30de\u30fc\u30c8\u30dd\u30a4\u30f3\u30bf\u3068\u306e\u7d44\u307f\u5408\u308f\u305b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u5b9f\u884c\u6642\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e0d\u8981\u306a\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30b7\u30e7\u30f3\/\u30c7\u30b9\u30c8\u30e9\u30af\u30b7\u30e7\u30f3\u306e\u56de\u907f<\/li>\n\n\n\n<li>\u52b9\u7387\u7684\u306a\u5024\u306e\u521d\u671f\u5316\u3068\u66f4\u65b0<\/li>\n\n\n\n<li>\u30ad\u30e3\u30c3\u30b7\u30e5\u30d5\u30ec\u30f3\u30c9\u30ea\u30fc\u306a\u8a2d\u8a08<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u6700\u9069\u5316\u30c6\u30af\u30cb\u30c3\u30af\u3092\u9069\u5207\u306b\u9069\u7528\u3059\u308b\u3053\u3068\u3067\u3001std::optional\u3092\u4f7f\u7528\u3057\u3064\u3064\u3082\u9ad8\u3044\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u7dad\u6301\u3059\u308b\u3053\u3068\u304c\u53ef\u80fd\u3067\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u77e5\u8b58\u3092\u6d3b\u304b\u3057\u305f\u5177\u4f53\u7684\u306a\u5b9f\u88c5\u4f8b\u3068\u8a2d\u8a08\u30d1\u30bf\u30fc\u30f3\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-14\">\u30aa\u30d7\u30b7\u30e7\u30f3\u3092\u4f7f\u3063\u305f\u5b9f\u88c5\u4f8b\u3068\u8a2d\u8a08\u30d1\u30bf\u30fc\u30f3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-15\">\u975e\u540c\u671f\u51e6\u7406\u306b\u304a\u3051\u308b\u623b\u308a\u5024\u3068\u3057\u3066\u306eoptional\u306e\u6d3b\u7528<\/h3>\n\n\n\n<p>\u975e\u540c\u671f\u51e6\u7406\u3067\u306estd::optional\u306e\u52b9\u679c\u7684\u306a\u4f7f\u7528\u65b9\u6cd5\u3092\u793a\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#include &lt;optional&gt;\n#include &lt;future&gt;\n#include &lt;thread&gt;\n#include &lt;queue&gt;\n#include &lt;mutex&gt;\n\nclass AsyncProcessor {\nprivate:\n    std::mutex mtx;\n    std::queue&lt;Task&gt; taskQueue;\n\npublic:\n    \/\/ 1. \u975e\u540c\u671f\u30bf\u30b9\u30af\u306e\u7d50\u679c\u3092\u8868\u73fe\n    std::future&lt;std::optional&lt;Result&gt;&gt; processAsync(const Task&amp; task) {\n        return std::async(std::launch::async, [this, task]() {\n            try {\n                auto result = process(task);\n                return std::optional&lt;Result&gt;(result);\n            } catch (const ProcessingError&amp;) {\n                return std::optional&lt;Result&gt;();\n            }\n        });\n    }\n\n    \/\/ 2. \u975e\u540c\u671f\u30ad\u30e5\u30fc\u304b\u3089\u306e\u8981\u7d20\u53d6\u5f97\n    std::optional&lt;Task&gt; tryGetNextTask() {\n        std::lock_guard&lt;std::mutex&gt; lock(mtx);\n        if (taskQueue.empty()) {\n            return std::nullopt;\n        }\n        Task task = std::move(taskQueue.front());\n        taskQueue.pop();\n        return task;\n    }\n};\n\n\/\/ 3. \u975e\u540c\u671f\u51e6\u7406\u306e\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u5b9f\u88c5\ntemplate&lt;typename T&gt;\nclass AsyncOperation {\npublic:\n    std::optional&lt;T&gt; executeWithTimeout(\n        std::chrono::milliseconds timeout) {\n\n        auto future = std::async(std::launch::async, &amp;AsyncOperation::execute, this);\n\n        if (future.wait_for(timeout) == std::future_status::timeout) {\n            return std::nullopt;\n        }\n\n        try {\n            return future.get();\n        } catch (...) {\n            return std::nullopt;\n        }\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-16\">\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u6a5f\u80fd\u306e\u5b9f\u88c5\u306b\u304a\u3051\u308boptional\u306e\u4f7f\u7528<\/h3>\n\n\n\n<p>\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u30ed\u30b8\u30c3\u30af\u306b\u304a\u3051\u308bstd::optional\u306e\u6d3b\u7528\u4f8b\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class Validator {\npublic:\n    \/\/ 1. \u8907\u5408\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\n    template&lt;typename T&gt;\n    static std::optional&lt;T&gt; validate(const T&amp; value,\n        const std::vector&lt;std::function&lt;bool(const T&amp;)&gt;&gt;&amp; rules) {\n\n        for (const auto&amp; rule : rules) {\n            if (!rule(value)) {\n                return std::nullopt;\n            }\n        }\n        return value;\n    }\n\n    \/\/ 2. \u5909\u63db\u3092\u4f34\u3046\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\n    static std::optional&lt;EmailAddress&gt; validateEmail(\n        const std::string&amp; input) {\n\n        if (!isValidFormat(input)) {\n            return std::nullopt;\n        }\n\n        return EmailAddress(input);\n    }\n\n    \/\/ 3. \u30c1\u30a7\u30fc\u30f3\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\n    class ValidationChain {\n    private:\n        std::optional&lt;std::string&gt; value;\n\n    public:\n        ValidationChain(const std::string&amp; initial) : value(initial) {}\n\n        ValidationChain&amp; notEmpty() {\n            if (value &amp;&amp; value-&gt;empty()) {\n                value = std::nullopt;\n            }\n            return *this;\n        }\n\n        ValidationChain&amp; maxLength(size_t max) {\n            if (value &amp;&amp; value-&gt;length() &gt; max) {\n                value = std::nullopt;\n            }\n            return *this;\n        }\n\n        std::optional&lt;std::string&gt; result() {\n            return value;\n        }\n    };\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-17\">\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u9045\u5ef6\u521d\u671f\u5316\u30d1\u30bf\u30fc\u30f3\u306e\u5b9f\u73fe<\/h3>\n\n\n\n<p>\u9045\u5ef6\u521d\u671f\u5316\u3068\u30ad\u30e3\u30c3\u30b7\u30e5\u30d1\u30bf\u30fc\u30f3\u306e\u5b9f\u88c5\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ 1. \u30b7\u30f3\u30b0\u30eb\u30c8\u30f3\u306e\u9045\u5ef6\u521d\u671f\u5316\nclass Singleton {\nprivate:\n    static std::optional&lt;Singleton&gt; instance;\n    Singleton() = default;\n\npublic:\n    static Singleton&amp; getInstance() {\n        if (!instance) {\n            instance.emplace();\n        }\n        return *instance;\n    }\n};\n\n\/\/ 2. \u30ea\u30bd\u30fc\u30b9\u30ad\u30e3\u30c3\u30b7\u30e5\ntemplate&lt;typename Key, typename Resource&gt;\nclass ResourceCache {\nprivate:\n    std::unordered_map&lt;Key, std::optional&lt;Resource&gt;&gt; cache;\n    std::mutex mtx;\n\npublic:\n    Resource&amp; getResource(const Key&amp; key) {\n        std::lock_guard&lt;std::mutex&gt; lock(mtx);\n        auto&amp; optResource = cache[key];\n        if (!optResource) {\n            optResource = loadResource(key);\n        }\n        return *optResource;\n    }\n\n    void invalidate(const Key&amp; key) {\n        std::lock_guard&lt;std::mutex&gt; lock(mtx);\n        cache[key].reset();\n    }\n};\n\n\/\/ 3. \u30d7\u30ed\u30ad\u30b7\u30d1\u30bf\u30fc\u30f3\u3067\u306e\u6d3b\u7528\ntemplate&lt;typename T&gt;\nclass LazyProxy {\nprivate:\n    std::optional&lt;T&gt; instance;\n    std::function&lt;T()&gt; factory;\n\npublic:\n    explicit LazyProxy(std::function&lt;T()&gt; f) \n        : factory(std::move(f)) {}\n\n    T&amp; get() {\n        if (!instance) {\n            instance = factory();\n        }\n        return *instance;\n    }\n\n    void reset() {\n        instance.reset();\n    }\n};<\/pre>\n\n\n\n<p>\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u306e\u6d3b\u7528\u30dd\u30a4\u30f3\u30c8\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u975e\u540c\u671f\u51e6\u7406\u3067\u306e\u6d3b\u7528<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30bf\u30a4\u30e0\u30a2\u30a6\u30c8\u51e6\u7406\u306e\u7c21\u6f54\u306a\u5b9f\u88c5<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u660e\u78ba\u306a\u8868\u73fe<\/li>\n\n\n\n<li>\u975e\u540c\u671f\u7d50\u679c\u306e\u578b\u5b89\u5168\u306a\u53d6\u308a\u6271\u3044<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u30d0\u30ea\u30c7\u30fc\u30b7\u30e7\u30f3\u3067\u306e\u6d3b\u7528<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5165\u529b\u691c\u8a3c\u306e\u9023\u9396\u7684\u306a\u9069\u7528<\/li>\n\n\n\n<li>\u578b\u5b89\u5168\u306a\u5024\u306e\u5909\u63db<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u7d71\u4e00\u7684\u306a\u51e6\u7406<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u9045\u5ef6\u521d\u671f\u5316\u3067\u306e\u6d3b\u7528<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30ea\u30bd\u30fc\u30b9\u306e\u52b9\u7387\u7684\u306a\u7ba1\u7406<\/li>\n\n\n\n<li>\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u5b9f\u88c5<\/li>\n\n\n\n<li>\u30e1\u30e2\u30ea\u4f7f\u7528\u306e\u6700\u9069\u5316<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u30d1\u30bf\u30fc\u30f3\u3092\u9069\u5207\u306b\u7d44\u307f\u5408\u308f\u305b\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u5805\u7262\u3067\u4fdd\u5b88\u6027\u306e\u9ad8\u3044\u30b3\u30fc\u30c9\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u30d1\u30bf\u30fc\u30f3\u3092\u4f7f\u7528\u3059\u308b\u969b\u306e\u6ce8\u610f\u70b9\u3068\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3\u306b\u3064\u3044\u3066\u8aac\u660e\u3057\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-18\">\u30aa\u30d7\u30b7\u30e7\u30f3\u306b\u95a2\u3059\u308b\u6ce8\u610f\u70b9\u3068\u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f3<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-19\">\u4f8b\u5916\u51e6\u7406\u3068\u306e\u30ac\u30a4\u30c9\u30e9\u30a4\u30f3<\/h3>\n\n\n\n<p>std::optional\u3068\u4f8b\u5916\u51e6\u7406\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u969b\u306e\u6ce8\u610f\u70b9\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class ExceptionHandling {\npublic:\n    \/\/ \u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f31: \u4f8b\u5916\u3092\u7121\u8996\u3057\u305f\u5b9f\u88c5\n    std::optional&lt;int&gt; badParseInteger(const std::string&amp; str) {\n        try {\n            return std::stoi(str);  \/\/ \u4f8b\u5916\u3092\u30ad\u30e3\u30c3\u30c1\u305b\u305a\n        } catch (...) {\n            return std::nullopt;  \/\/ \u5168\u3066\u306e\u4f8b\u5916\u3092\u63e1\u308a\u3064\u3076\u3059\n        }\n    }\n\n    \/\/ \u63a8\u5968\u30d1\u30bf\u30fc\u30f31: \u9069\u5207\u306a\u4f8b\u5916\u51e6\u7406\n    std::optional&lt;int&gt; goodParseInteger(const std::string&amp; str) {\n        try {\n            size_t pos;\n            int value = std::stoi(str, &amp;pos);\n            \/\/ \u6587\u5b57\u5217\u5168\u4f53\u304c\u6570\u5024\u3067\u3042\u308b\u3053\u3068\u3092\u78ba\u8a8d\n            if (pos == str.length()) {\n                return value;\n            }\n            return std::nullopt;\n        } catch (const std::invalid_argument&amp;) {\n            return std::nullopt;  \/\/ \u6570\u5024\u5f62\u5f0f\u30a8\u30e9\u30fc\n        } catch (const std::out_of_range&amp;) {\n            return std::nullopt;  \/\/ \u7bc4\u56f2\u5916\u30a8\u30e9\u30fc\n        }\n    }\n\n    \/\/ \u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f32: \u4e0d\u9069\u5207\u306a\u4f8b\u5916\u306e\u4f7f\u7528\n    int badGetValue(const std::optional&lt;int&gt;&amp; opt) {\n        if (!opt) {\n            throw std::runtime_error(\"Value not present\");  \/\/ optional\u306e\u610f\u5473\u3092\u7121\u52b9\u5316\n        }\n        return *opt;\n    }\n\n    \/\/ \u63a8\u5968\u30d1\u30bf\u30fc\u30f32: value_or\u306e\u6d3b\u7528\n    int goodGetValue(const std::optional&lt;int&gt;&amp; opt) {\n        return opt.value_or(-1);  \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u3092\u63d0\u4f9b\n    }\n};\n\n\/\/ \u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f33: \u904e\u5270\u306aoptional\u306e\u5165\u308c\u5b50\nclass NestedOptionals {\n    \/\/ \u60aa\u3044\u4f8b\n    std::optional&lt;std::optional&lt;std::string&gt;&gt; badNestedOptional;\n\n    \/\/ \u826f\u3044\u4f8b\n    std::optional&lt;std::string&gt; goodOptional;\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-20\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3078\u306e\u5f71\u97ff\u3092\u8003\u616e\u3057\u305f\u9069\u5207\u306a\u4f7f\u7528\u5834\u9762<\/h3>\n\n\n\n<p>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u89b3\u70b9\u304b\u3089\u898b\u305f\u9069\u5207\u306a\u4f7f\u7528\u65b9\u6cd5\u3068\u6ce8\u610f\u70b9\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">class PerformanceConsiderations {\npublic:\n    \/\/ \u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f31: \u4e0d\u5fc5\u8981\u306aoptional\u306e\u4f7f\u7528\n    class BadExample {\n        std::optional&lt;int&gt; count{0};  \/\/ \u5e38\u306b\u5024\u3092\u6301\u3064\u5834\u5408\u306foptional\u4e0d\u8981\n        std::optional&lt;std::string&gt; name{\"default\"};  \/\/ \u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u304c\u3042\u308b\u5834\u5408\u306f\u4e0d\u8981\n    };\n\n    \/\/ \u63a8\u5968\u30d1\u30bf\u30fc\u30f31: \u5fc5\u8981\u306a\u5834\u5408\u306e\u307foptional\u3092\u4f7f\u7528\n    class GoodExample {\n        int count{0};  \/\/ \u901a\u5e38\u306e\u5909\u6570\u3067\u5341\u5206\n        std::optional&lt;std::string&gt; nickname;  \/\/ \u672c\u5f53\u306b\u30aa\u30d7\u30b7\u30e7\u30ca\u30eb\u306a\u5834\u5408\n    };\n\n    \/\/ \u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f32: \u5927\u304d\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306e\u76f4\u63a5\u4fdd\u6301\n    class BadLargeObject {\n        std::optional&lt;HugeObject&gt; obj;  \/\/ \u30e1\u30e2\u30ea\u52b9\u7387\u304c\u60aa\u3044\n    };\n\n    \/\/ \u63a8\u5968\u30d1\u30bf\u30fc\u30f32: \u53c2\u7167\u307e\u305f\u306f\u5171\u6709\u30dd\u30a4\u30f3\u30bf\u306e\u4f7f\u7528\n    class GoodLargeObject {\n        std::optional&lt;std::reference_wrapper&lt;HugeObject&gt;&gt; obj;  \/\/ \u30e1\u30e2\u30ea\u52b9\u7387\u304c\u826f\u3044\n    };\n\n    \/\/ \u30a2\u30f3\u30c1\u30d1\u30bf\u30fc\u30f33: \u983b\u7e41\u306a\u5024\u306e\u78ba\u8a8d\u3068\u53d6\u5f97\n    void badUsage(const std::optional&lt;std::string&gt;&amp; data) {\n        if (data.has_value()) {\n            std::string value = data.value();  \/\/ \u4f59\u5206\u306a\u30b3\u30d4\u30fc\n            \/\/ \u51e6\u7406...\n        }\n    }\n\n    \/\/ \u63a8\u5968\u30d1\u30bf\u30fc\u30f33: \u52b9\u7387\u7684\u306a\u5024\u306e\u5229\u7528\n    void goodUsage(const std::optional&lt;std::string&gt;&amp; data) {\n        if (data) {\n            const auto&amp; value = *data;  \/\/ \u53c2\u7167\u3067\u53d6\u5f97\n            \/\/ \u51e6\u7406...\n        }\n    }\n};\n\n\/\/ \u91cd\u8981\u306a\u6ce8\u610f\u70b9\u3068\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9\u306e\u307e\u3068\u3081\nclass OptionalGuidelines {\npublic:\n    \/\/ 1. \u5024\u306e\u5b58\u5728\u78ba\u8a8d\n    template&lt;typename T&gt;\n    void processValue(const std::optional&lt;T&gt;&amp; opt) {\n        \/\/ \u63a8\u5968: \u660e\u793a\u7684\u306a\u5b58\u5728\u78ba\u8a8d\n        if (opt) {\n            const auto&amp; value = *opt;\n            \/\/ \u51e6\u7406...\n        }\n\n        \/\/ \u975e\u63a8\u5968: value()\u306e\u76f4\u63a5\u547c\u3073\u51fa\u3057\n        \/\/ opt.value();  \/\/ \u4f8b\u5916\u3092\u30b9\u30ed\u30fc\u3059\u308b\u53ef\u80fd\u6027\u3042\u308a\n    }\n\n    \/\/ 2. \u6761\u4ef6\u5206\u5c90\u3067\u306e\u4f7f\u7528\n    template&lt;typename T&gt;\n    void handleOptional(const std::optional&lt;T&gt;&amp; opt) {\n        \/\/ \u63a8\u5968: boolean\u30b3\u30f3\u30d0\u30fc\u30b8\u30e7\u30f3\u306e\u5229\u7528\n        if (opt) {\n            \/\/ \u51e6\u7406...\n        }\n\n        \/\/ \u975e\u63a8\u5968: has_value\u306e\u5197\u9577\u306a\u4f7f\u7528\n        \/\/ if (opt.has_value()) {\n        \/\/     \/\/ \u51e6\u7406...\n        \/\/ }\n    }\n\n    \/\/ 3. \u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u63d0\u4f9b\n    template&lt;typename T&gt;\n    T getValueWithDefault(const std::optional&lt;T&gt;&amp; opt, const T&amp; defaultValue) {\n        \/\/ \u63a8\u5968: value_or\u306e\u4f7f\u7528\n        return opt.value_or(defaultValue);\n\n        \/\/ \u975e\u63a8\u5968: \u624b\u52d5\u3067\u306e\u6761\u4ef6\u5206\u5c90\n        \/\/ if (opt.has_value()) {\n        \/\/     return opt.value();\n        \/\/ }\n        \/\/ return defaultValue;\n    }\n};<\/pre>\n\n\n\n<p>\u4e3b\u306a\u6ce8\u610f\u70b9\u306e\u307e\u3068\u3081\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u4f8b\u5916\u51e6\u7406\u95a2\u9023<\/strong> \u72b6\u6cc1 \u63a8\u5968\u30a2\u30d7\u30ed\u30fc\u30c1 \u907f\u3051\u308b\u3079\u304d\u30a2\u30d7\u30ed\u30fc\u30c1 \u5024\u306e\u53d6\u5f97 value_or\u306e\u4f7f\u7528 \u76f4\u63a5\u7684\u306a\u4f8b\u5916\u30b9\u30ed\u30fc \u30a8\u30e9\u30fc\u51e6\u7406 \u9069\u5207\u306a\u4f8b\u5916\u306e\u4f1d\u642c \u4f8b\u5916\u306e\u63e1\u308a\u3064\u3076\u3057 null\u78ba\u8a8d \u660e\u793a\u7684\u306a\u30c1\u30a7\u30c3\u30af \u6697\u9ed9\u7684\u306a\u4eee\u5b9a<\/li>\n\n\n\n<li><strong>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u8003\u616e\u70b9<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e0d\u5fc5\u8981\u306aoptional\u306e\u4f7f\u7528\u3092\u907f\u3051\u308b<\/li>\n\n\n\n<li>\u5927\u304d\u306a\u30aa\u30d6\u30b8\u30a7\u30af\u30c8\u306f\u53c2\u7167\u3068\u3057\u3066\u4fdd\u6301<\/li>\n\n\n\n<li>\u30b3\u30d4\u30fc\u306e\u6700\u5c0f\u5316\u3092\u610f\u8b58\u3059\u308b<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u8a2d\u8a08\u4e0a\u306e\u6ce8\u610f\u70b9<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>optional\u306e\u5165\u308c\u5b50\u3092\u907f\u3051\u308b<\/li>\n\n\n\n<li>\u660e\u78ba\u306a\u610f\u56f3\u3092\u6301\u3063\u3066\u4f7f\u7528\u3059\u308b<\/li>\n\n\n\n<li>\u9069\u5207\u306a\u30c7\u30d5\u30a9\u30eb\u30c8\u5024\u306e\u63d0\u4f9b<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u6ce8\u610f\u70b9\u3092\u610f\u8b58\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u52b9\u679c\u7684\u306bstd::optional\u3092\u6d3b\u7528\u3067\u304d\u307e\u3059\u3002\u6b21\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3088\u308a\u6df1\u3044optional\u306e\u7406\u89e3\u306e\u305f\u3081\u306b\u3001\u4ed6\u306e\u6a5f\u80fd\u3084\u8a00\u8a9e\u3068\u306e\u6bd4\u8f03\u3092\u884c\u3044\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-21\">\u3088\u308a\u6df1\u3044\u30aa\u30d7\u30b7\u30e7\u30f3\u306e\u7406\u89e3\u306e\u305f\u3081\u306b<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-22\">C++17 \u4ee5\u964d\u306e\u65b0\u6a5f\u80fd\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\u6d3b\u7528\u6cd5<\/h3>\n\n\n\n<p>\u30e2\u30c0\u30f3C++\u306e\u65b0\u6a5f\u80fd\u3068std::optional\u3092\u7d44\u307f\u5408\u308f\u305b\u305f\u9ad8\u5ea6\u306a\u4f7f\u7528\u65b9\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#include &lt;optional&gt;\n#include &lt;variant&gt;\n#include &lt;string_view&gt;\n\nclass ModernCppFeatures {\npublic:\n    \/\/ 1. \u69cb\u9020\u5316\u675f\u7e1b\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\n    std::pair&lt;std::optional&lt;int&gt;, std::string_view&gt; \n    parseValue(std::string_view input) {\n        if (input.empty()) {\n            return {std::nullopt, \"Empty input\"};\n        }\n        try {\n            return {std::stoi(std::string(input)), \"Success\"};\n        } catch (...) {\n            return {std::nullopt, \"Parse error\"};\n        }\n    }\n\n    void demonstrateStructuredBinding() {\n        auto [value, message] = parseValue(\"123\");\n        if (value) {\n            std::cout &lt;&lt; \"Parsed value: \" &lt;&lt; *value &lt;&lt; \"\\n\";\n        }\n    }\n\n    \/\/ 2. std::variant\u3068\u306e\u7d44\u307f\u5408\u308f\u305b\n    class Result {\n    public:\n        using ErrorType = std::variant&lt;std::string, int, std::exception_ptr&gt;;\n\n        template&lt;typename T&gt;\n        static Result success(T&amp;&amp; value) {\n            return Result(std::optional&lt;T&gt;(std::forward&lt;T&gt;(value)));\n        }\n\n        template&lt;typename E&gt;\n        static Result error(E&amp;&amp; error) {\n            return Result(ErrorType(std::forward&lt;E&gt;(error)));\n        }\n\n    private:\n        std::optional&lt;int&gt; value;\n        std::optional&lt;ErrorType&gt; error;\n    };\n\n    \/\/ 3. C++20\u306erange\u5bfe\u5fdc\n    template&lt;typename Range&gt;\n    auto findFirstValid(Range&amp;&amp; range) {\n        using T = std::ranges::range_value_t&lt;Range&gt;;\n        return std::ranges::find_if(\n            std::forward&lt;Range&gt;(range),\n            [](const auto&amp; item) { return item.has_value(); }\n        );\n    }\n};\n\n\/\/ 4. \u30b3\u30f3\u30bb\u30d7\u30c8\u3068\u306e\u7d71\u5408\uff08C++20\uff09\ntemplate&lt;typename T&gt;\nconcept OptionalLike = requires(T t) {\n    { t.has_value() } -&gt; std::convertible_to&lt;bool&gt;;\n    { *t } -&gt; std::convertible_to&lt;typename T::value_type&gt;;\n};\n\ntemplate&lt;OptionalLike Opt&gt;\nvoid processOptional(const Opt&amp; opt) {\n    if (opt) {\n        std::cout &lt;&lt; \"Value: \" &lt;&lt; *opt &lt;&lt; \"\\n\";\n    }\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-23\">\u4ed6\u8a00\u8a9e\u306b\u304a\u3051\u308b\u540c\u69d8\u306e\u6a5f\u80fd\u3068\u306e\u6bd4\u8f03<\/h3>\n\n\n\n<p>\u4ed6\u306e\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u8a00\u8a9e\u306b\u304a\u3051\u308bOptional\u578b\u76f8\u5f53\u306e\u6a5f\u80fd\u3068\u306e\u6bd4\u8f03\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ 1. Rust\u306eOption\u578b\u306b\u76f8\u5f53\u3059\u308b\u5b9f\u88c5\ntemplate&lt;typename T&gt;\nclass RustLikeOption {\npublic:\n    \/\/ Some\u5024\u306e\u4f5c\u6210\n    static RustLikeOption some(T value) {\n        return RustLikeOption(std::move(value));\n    }\n\n    \/\/ None\u5024\u306e\u4f5c\u6210\n    static RustLikeOption none() {\n        return RustLikeOption();\n    }\n\n    \/\/ unwrap_or_default\u76f8\u5f53\u306e\u5b9f\u88c5\n    T unwrap_or_default() const {\n        return value.value_or(T());\n    }\n\n    \/\/ map\u64cd\u4f5c\u306e\u5b9f\u88c5\n    template&lt;typename F&gt;\n    auto map(F&amp;&amp; f) const -&gt; RustLikeOption&lt;decltype(f(std::declval&lt;T&gt;()))&gt; {\n        if (value) {\n            return RustLikeOption&lt;decltype(f(*value))&gt;::some(f(*value));\n        }\n        return RustLikeOption&lt;decltype(f(std::declval&lt;T&gt;()))&gt;::none();\n    }\n\nprivate:\n    std::optional&lt;T&gt; value;\n    RustLikeOption() = default;\n    explicit RustLikeOption(T v) : value(std::move(v)) {}\n};\n\n\/\/ 2. Kotlin\u306enullable\u578b\u306b\u76f8\u5f53\u3059\u308b\u6a5f\u80fd\ntemplate&lt;typename T&gt;\nclass KotlinLikeNullable {\npublic:\n    \/\/ let\u64cd\u4f5c\u306e\u5b9f\u88c5\n    template&lt;typename F&gt;\n    auto let(F&amp;&amp; f) const -&gt; decltype(f(std::declval&lt;T&gt;())) {\n        if (value) {\n            return f(*value);\n        }\n        return decltype(f(std::declval&lt;T&gt;()))();\n    }\n\n    \/\/ elvis\u6f14\u7b97\u5b50\u76f8\u5f53\u306e\u5b9f\u88c5\n    T elvis(const T&amp; defaultValue) const {\n        return value.value_or(defaultValue);\n    }\n\nprivate:\n    std::optional&lt;T&gt; value;\n};\n\n\/\/ 3. Scala \u306eOption\u578b\u306b\u76f8\u5f53\u3059\u308b\u5b9f\u88c5\ntemplate&lt;typename T&gt;\nclass ScalaLikeOption {\npublic:\n    \/\/ flatMap\u64cd\u4f5c\u306e\u5b9f\u88c5\n    template&lt;typename F&gt;\n    auto flatMap(F&amp;&amp; f) const -&gt; decltype(f(std::declval&lt;T&gt;())) {\n        if (value) {\n            return f(*value);\n        }\n        return decltype(f(std::declval&lt;T&gt;()))();\n    }\n\n    \/\/ getOrElse\u76f8\u5f53\u306e\u5b9f\u88c5\n    template&lt;typename F&gt;\n    T getOrElse(F&amp;&amp; f) const {\n        return value.value_or_else(std::forward&lt;F&gt;(f));\n    }\n\nprivate:\n    std::optional&lt;T&gt; value;\n};<\/pre>\n\n\n\n<p>\u8a00\u8a9e\u9593\u306e\u6bd4\u8f03\u8868\uff1a<\/p>\n\n\n<div id=\"id-e43d658c-e808-4eda-9878-1a661d6f73f9\">\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u8a00\u8a9e<\/th><th>\u578b\u540d<\/th><th>\u7279\u5fb4<\/th><th>C++\u3068\u306e\u4e3b\u306a\u9055\u3044<\/th><\/tr><\/thead><tbody><tr><td>C++<\/td><td>std::optional<\/td><td>\u578b\u5b89\u5168\u3001\u5024\u30bb\u30de\u30f3\u30c6\u30a3\u30af\u30b9<\/td><td>\u2013<\/td><\/tr><tr><td>Rust<\/td><td>Option<\/td><td>\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u30f3\u30b0\u3001\u8c4a\u5bcc\u306a\u30e1\u30bd\u30c3\u30c9<\/td><td>\u3088\u308a\u5f37\u529b\u306a\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u30f3\u30b0<\/td><\/tr><tr><td>Kotlin<\/td><td>Nullable\u578b<\/td><td>\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u7d71\u5408\u3001null\u5b89\u5168\u6027<\/td><td>\u30b3\u30f3\u30d1\u30a4\u30eb\u6642\u306enull\u691c\u67fb<\/td><\/tr><tr><td>Swift<\/td><td>Optional<\/td><td>\u81ea\u52d5\u30a2\u30f3\u30e9\u30c3\u30d7\u3001\u30c1\u30a7\u30fc\u30f3<\/td><td>\u3088\u308a\u7c21\u6f54\u306a\u69cb\u6587<\/td><\/tr><tr><td>Scala<\/td><td>Option<\/td><td>\u95a2\u6570\u578b\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u7d71\u5408<\/td><td>\u30e2\u30ca\u30c9\u7684\u306a\u64cd\u4f5c\u304c\u8c4a\u5bcc<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n\n\n<p>\u5404\u8a00\u8a9e\u304b\u3089\u306e\u5b66\u3073\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Rust\u304b\u3089\u306e\u5b66\u3073<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u30f3\u30b0\u306e\u91cd\u8981\u6027<\/li>\n\n\n\n<li>\u5305\u62ec\u7684\u306aAPI\u30c7\u30b6\u30a4\u30f3<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u660e\u793a\u6027<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Kotlin\u304b\u3089\u306e\u5b66\u3073<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>null\u5b89\u5168\u6027\u306e\u8a2d\u8a08<\/li>\n\n\n\n<li>\u30d7\u30e9\u30c3\u30c8\u30d5\u30a9\u30fc\u30e0\u7d71\u5408\u306e\u65b9\u6cd5<\/li>\n\n\n\n<li>\u7c21\u6f54\u306a\u69cb\u6587\u306e\u91cd\u8981\u6027<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Scala\u304b\u3089\u306e\u5b66\u3073<\/strong><\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u95a2\u6570\u578b\u30d7\u30ed\u30b0\u30e9\u30df\u30f3\u30b0\u3068\u306e\u7d71\u5408<\/li>\n\n\n\n<li>\u30e2\u30ca\u30c9\u7684\u306a\u64cd\u4f5c\u306e\u6709\u7528\u6027<\/li>\n\n\n\n<li>\u578b\u30b7\u30b9\u30c6\u30e0\u306e\u67d4\u8edf\u6027<\/li>\n<\/ul>\n\n\n\n<p>\u3053\u308c\u3089\u306e\u77e5\u898b\u3092\u6d3b\u304b\u3059\u3053\u3068\u3067\u3001C++\u306estd::optional\u3092\u3088\u308a\u52b9\u679c\u7684\u306b\u6d3b\u7528\u3067\u304d\u307e\u3059\u3002\u4ed6\u8a00\u8a9e\u306e\u512a\u308c\u305f\u6a5f\u80fd\u3084\u8a2d\u8a08\u601d\u60f3\u3092\u7406\u89e3\u3059\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u826f\u3044\u30b3\u30fc\u30c9\u8a2d\u8a08\u304c\u53ef\u80fd\u306b\u306a\u308a\u307e\u3059\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Warning: Undefined array key &#8220;is_admin&#8221; in \/home\/xs392991\/dexall.co.jp\/public_html\/articles\/wp-content\/themes\/ &#8230; <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":{"0":"post-2107","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-cpp","7":"nothumb"},"_links":{"self":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/2107","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2107"}],"version-history":[{"count":1,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/2107\/revisions"}],"predecessor-version":[{"id":2108,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/2107\/revisions\/2108"}],"wp:attachment":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2107"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2107"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2107"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}