{"id":2089,"date":"2025-03-24T08:48:20","date_gmt":"2025-03-23T23:48:20","guid":{"rendered":"https:\/\/dexall.co.jp\/articles\/?p=2089"},"modified":"2025-03-24T08:48:46","modified_gmt":"2025-03-23T23:48:46","slug":"c-atoi%e3%81%ae%e5%ae%8c%e5%85%a8%e3%82%ac%e3%82%a4%e3%83%89%ef%bc%9a%e5%ae%89%e5%85%a8%e3%81%aa%e6%96%87%e5%ad%97%e5%88%97%e5%a4%89%e6%8f%9b%e3%81%ae%e3%81%9f%e3%82%81%e3%81%ae7%e3%81%a4%e3%81%ae","status":"publish","type":"post","link":"https:\/\/dexall.co.jp\/articles\/?p=2089","title":{"rendered":"C++ atoi\u306e\u5b8c\u5168\u30ac\u30a4\u30c9\uff1a\u5b89\u5168\u306a\u6587\u5b57\u5217\u5909\u63db\u306e\u305f\u3081\u306e7\u3064\u306e\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9"},"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++ atoi\u3068\u306f\uff1a\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-1\">atoi\u306e\u52d5\u4f5c\u539f\u7406\u3068\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-2\">atoi\u306e\u5371\u967a\u6027\u3068\u5236\u9650\u4e8b\u9805<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-3\">\u30e2\u30c0\u30f3C++\u3067\u306e\u6587\u5b57\u5217\u5909\u63db\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-4\">std::stoi vs atoi\uff1a\u5b89\u5168\u6027\u306e\u6bd4\u8f03<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-5\">\u6587\u5b57\u5217\u5909\u63db\u306e\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0\u624b\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-6\">atoi\u3092\u5b89\u5168\u306b\u4f7f\u7528\u3059\u308b7\u3064\u306e\u30b9\u30c6\u30c3\u30d7<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-7\">\u30b9\u30c6\u30c3\u30d71\uff1a\u5165\u529b\u5024\u306e\u59a5\u5f53\u6027\u691c\u8a3c<\/a>      <\/li>      <li>        <a href=\"#i-8\">\u30b9\u30c6\u30c3\u30d72\uff1a\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u5bfe\u7b56<\/a>      <\/li>      <li>        <a href=\"#i-9\">\u30b9\u30c6\u30c3\u30d73\uff1a\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u9069\u5207\u306a\u51e6\u7406<\/a>      <\/li>      <li>        <a href=\"#i-10\">\u30b9\u30c6\u30c3\u30d74\uff1a\u578b\u306e\u5b89\u5168\u6027\u78ba\u4fdd<\/a>      <\/li>      <li>        <a href=\"#i-11\">\u30b9\u30c6\u30c3\u30d75\uff1a\u7570\u5e38\u5024\u306e\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0<\/a>      <\/li>      <li>        <a href=\"#i-12\">\u30b9\u30c6\u30c3\u30d76\uff1a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u6700\u9069\u5316<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-13\">\u30b9\u30c6\u30c3\u30d77\uff1a\u5358\u4f53\u30c6\u30b9\u30c8\u306e\u5b9f\u88c5<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-14\">\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\u4f8b\u3067\u5b66\u3076atoi<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-15\">\u30ec\u30ac\u30b7\u30fc\u30b3\u30fc\u30c9\u306e\u30e2\u30c0\u30f3\u5316\u4e8b\u4f8b<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-16\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5\u4f8b<\/a>      <\/li>    <\/ul>  <\/li>  <li>    <a href=\"#i-17\">\u3088\u304f\u3042\u308batoi\u95a2\u9023\u306e\u30d0\u30b0\u3068\u5bfe\u7b56<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-18\">\u30e1\u30e2\u30ea\u7834\u58ca\u3092\u9632\u3050\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-19\">\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306e\u5b89\u5168\u306a\u4f7f\u7528\u6cd5<\/a>      <\/li>    <\/ul>  <\/li>  <li class=\"last\">    <a href=\"#i-20\">\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\uff1a\u3055\u3089\u306a\u308b\u5b66\u7fd2\u30ea\u30bd\u30fc\u30b9<\/a>    <ul class=\"menu_level_1\">      <li class=\"first\">        <a href=\"#i-21\">\u63a8\u5968\u3055\u308c\u308b\u4ee3\u66ff\u95a2\u6570\u3068\u30e9\u30a4\u30d6\u30e9\u30ea<\/a>      <\/li>      <li class=\"last\">        <a href=\"#i-22\">\u95a2\u9023\u3059\u308bC++\u6a19\u6e96\u30e9\u30a4\u30d6\u30e9\u30ea\u306e\u6a5f\u80fd<\/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++ atoi\u3068\u306f\uff1a\u57fa\u790e\u304b\u3089\u5fdc\u7528\u307e\u3067<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-1\">atoi\u306e\u52d5\u4f5c\u539f\u7406\u3068\u57fa\u672c\u7684\u306a\u4f7f\u3044\u65b9<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">atoi\uff08ASCII to Integer\uff09\u306f\u3001C\u8a00\u8a9e\u304b\u3089\u7d99\u627f\u3055\u308c\u305fC++\u306e\u95a2\u6570\u3067\u3001\u6587\u5b57\u5217\u3092\u6574\u6570\u5024\u306b\u5909\u63db\u3059\u308b\u305f\u3081\u306e\u57fa\u672c\u7684\u306a\u95a2\u6570\u3067\u3059\u3002stdlib.h\u30d8\u30c3\u30c0\u30fc\u30d5\u30a1\u30a4\u30eb\uff08C++\u3067\u306fcstdlib\uff09\u306b\u5b9a\u7fa9\u3055\u308c\u3066\u304a\u308a\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u7279\u5fb4\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=\"\">\/\/ atoi\u306e\u57fa\u672c\u7684\u306a\u4f7f\u7528\u4f8b\n#include &lt;cstdlib&gt;\n#include &lt;iostream&gt;\n\nint main() {\n    const char* str1 = \"123\";\n    int num1 = atoi(str1);    \/\/ \u7d50\u679c: 123\n\n    const char* str2 = \"  456\";  \/\/ \u5148\u982d\u306e\u7a7a\u767d\u306f\u7121\u8996\u3055\u308c\u308b\n    int num2 = atoi(str2);    \/\/ \u7d50\u679c: 456\n\n    const char* str3 = \"789abc\";  \/\/ \u6570\u5b57\u4ee5\u5916\u306e\u6587\u5b57\u304c\u51fa\u73fe\u3057\u305f\u6642\u70b9\u3067\u5909\u63db\u7d42\u4e86\n    int num3 = atoi(str3);    \/\/ \u7d50\u679c: 789\n\n    std::cout &lt;&lt; \"num1: \" &lt;&lt; num1 &lt;&lt; std::endl;\n    std::cout &lt;&lt; \"num2: \" &lt;&lt; num2 &lt;&lt; std::endl;\n    std::cout &lt;&lt; \"num3: \" &lt;&lt; num3 &lt;&lt; std::endl;\n\n    return 0;\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">atoi\u95a2\u6570\u306e\u4e3b\u306a\u7279\u5fb4\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5f15\u6570\u3068\u3057\u3066<code>const char*<\/code>\u578b\u306e\u6587\u5b57\u5217\u3092\u53d7\u3051\u53d6\u308b<\/li>\n\n\n\n<li>\u6587\u5b57\u5217\u306e\u5148\u982d\u304b\u3089\u6570\u5024\u3068\u3057\u3066\u89e3\u91c8\u53ef\u80fd\u306a\u90e8\u5206\u3092\u6574\u6570\u306b\u5909\u63db<\/li>\n\n\n\n<li>\u5148\u982d\u306e\u7a7a\u767d\u6587\u5b57\uff08\u30b9\u30da\u30fc\u30b9\u3001\u30bf\u30d6\u3001\u6539\u884c\uff09\u306f\u7121\u8996\u3055\u308c\u308b<\/li>\n\n\n\n<li>\u7b26\u53f7\uff08+\/-\uff09\u306b\u3082\u5bfe\u5fdc<\/li>\n\n\n\n<li>\u6570\u5024\u3068\u3057\u3066\u89e3\u91c8\u3067\u304d\u306a\u3044\u6587\u5b57\u304c\u51fa\u73fe\u3057\u305f\u6642\u70b9\u3067\u5909\u63db\u3092\u7d42\u4e86<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-2\">atoi\u306e\u5371\u967a\u6027\u3068\u5236\u9650\u4e8b\u9805<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u3057\u304b\u3057\u3001atoi\u95a2\u6570\u306b\u306f\u4ee5\u4e0b\u306e\u3088\u3046\u306a\u91cd\u5927\u306a\u554f\u984c\u304c\u3042\u308a\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u691c\u51fa\u306e\u6b20\u5982<\/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=\"\">#include &lt;cstdlib&gt;\n#include &lt;iostream&gt;\n\nint main() {\n    \/\/ \u30a8\u30e9\u30fc\u30b1\u30fc\u30b9\u306e\u4f8b\n    const char* invalid_str = \"hello\";  \/\/ \u6570\u5024\u3067\u306a\u3044\u6587\u5b57\u5217\n    int result = atoi(invalid_str);     \/\/ \u623b\u308a\u5024: 0\n\n    \/\/ 0\u304c\u6b63\u5e38\u306a\u5165\u529b\u5024\u306a\u306e\u304b\u3001\u30a8\u30e9\u30fc\u306a\u306e\u304b\u5224\u5225\u3067\u304d\u306a\u3044\n    const char* zero_str = \"0\";\n    int zero_result = atoi(zero_str);   \/\/ \u623b\u308a\u5024: 0\n\n    std::cout &lt;&lt; \"Invalid string conversion: \" &lt;&lt; result &lt;&lt; std::endl;\n    std::cout &lt;&lt; \"Zero string conversion: \" &lt;&lt; zero_result &lt;&lt; std::endl;\n\n    return 0;\n}<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u306e\u672a\u691c\u51fa<\/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=\"\">#include &lt;cstdlib&gt;\n#include &lt;iostream&gt;\n#include &lt;limits&gt;\n\nint main() {\n    \/\/ \u6574\u6570\u306e\u6700\u5927\u5024\u3092\u8d85\u3048\u308b\u5024\n    const char* overflow_str = \"999999999999999999999\";\n    int overflow_result = atoi(overflow_str);  \/\/ \u672a\u5b9a\u7fa9\u52d5\u4f5c\n\n    std::cout &lt;&lt; \"Overflow result: \" &lt;&lt; overflow_result &lt;&lt; std::endl;\n    std::cout &lt;&lt; \"INT_MAX: \" &lt;&lt; std::numeric_limits&lt;int&gt;::max() &lt;&lt; std::endl;\n\n    return 0;\n}<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li>\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u30ea\u30b9\u30af<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30d0\u30c3\u30d5\u30a1\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u306e\u53ef\u80fd\u6027<\/li>\n\n\n\n<li>\u5165\u529b\u5024\u306e\u691c\u8a3c\u6a5f\u80fd\u304c\u306a\u3044<\/li>\n\n\n\n<li>\u4e88\u671f\u3057\u306a\u3044\u52d5\u4f5c\u306b\u3088\u308b\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3\u8106\u5f31\u6027<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u554f\u984c\u306b\u3088\u308a\u3001\u30e2\u30c0\u30f3C++\u3067\u306f<code>std::stoi<\/code>\u3084<code>std::stringstream<\/code>\u306a\u3069\u306e\u5b89\u5168\u306a\u4ee3\u66ff\u624b\u6bb5\u304c\u63a8\u5968\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u4ee5\u964d\u306e\u30bb\u30af\u30b7\u30e7\u30f3\u3067\u306f\u3001\u3053\u308c\u3089\u306e\u554f\u984c\u306b\u5bfe\u3059\u308b\u5177\u4f53\u7684\u306a\u5bfe\u7b56\u3068\u3001\u3088\u308a\u5b89\u5168\u306a\u5b9f\u88c5\u65b9\u6cd5\u306b\u3064\u3044\u3066\u8a73\u3057\u304f\u89e3\u8aac\u3057\u3066\u3044\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-3\">\u30e2\u30c0\u30f3C++\u3067\u306e\u6587\u5b57\u5217\u5909\u63db\u30d9\u30b9\u30c8\u30d7\u30e9\u30af\u30c6\u30a3\u30b9<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-4\">std::stoi vs atoi\uff1a\u5b89\u5168\u6027\u306e\u6bd4\u8f03<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u30e2\u30c0\u30f3C++\u3067\u306f\u3001\u6587\u5b57\u5217\u304b\u3089\u6574\u6570\u3078\u306e\u5909\u63db\u306b\u304a\u3044\u3066<code>std::stoi<\/code>\u306e\u4f7f\u7528\u304c\u63a8\u5968\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u4ee5\u4e0b\u306b\u3001<code>atoi<\/code>\u3068<code>std::stoi<\/code>\u306e\u4e3b\u306a\u9055\u3044\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;iostream&gt;\n#include &lt;string&gt;\n#include &lt;stdexcept&gt;\n\nvoid compare_conversion_methods() {\n    \/\/ std::stoi\u306e\u4f7f\u7528\u4f8b\n    try {\n        \/\/ \u6b63\u5e38\u306a\u5909\u63db\n        std::string normal = \"123\";\n        int result1 = std::stoi(normal);\n        std::cout &lt;&lt; \"\u6b63\u5e38\u306a\u5909\u63db: \" &lt;&lt; result1 &lt;&lt; std::endl;\n\n        \/\/ \u7121\u52b9\u306a\u5165\u529b\u306e\u691c\u51fa\n        std::string invalid = \"abc\";\n        int result2 = std::stoi(invalid);  \/\/ std::invalid_argument\u304c\u6295\u3052\u3089\u308c\u308b\n    }\n    catch (const std::invalid_argument&amp; e) {\n        std::cout &lt;&lt; \"\u7121\u52b9\u306a\u5165\u529b\u3092\u691c\u51fa: \" &lt;&lt; e.what() &lt;&lt; std::endl;\n    }\n    catch (const std::out_of_range&amp; e) {\n        std::cout &lt;&lt; \"\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u3092\u691c\u51fa: \" &lt;&lt; e.what() &lt;&lt; std::endl;\n    }\n\n    \/\/ atoi\u306e\u4f7f\u7528\u4f8b\uff08\u30a8\u30e9\u30fc\u691c\u51fa\u306a\u3057\uff09\n    const char* invalid_c = \"abc\";\n    int result3 = atoi(invalid_c);  \/\/ \u623b\u308a\u5024: 0\uff08\u30a8\u30e9\u30fc\u304b\u6b63\u5e38\u306a0\u304b\u533a\u5225\u3067\u304d\u306a\u3044\uff09\n    std::cout &lt;&lt; \"atoi\u3067\u306e\u7121\u52b9\u306a\u5165\u529b: \" &lt;&lt; result3 &lt;&lt; std::endl;\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">std::stoi\u306e\u4e3b\u306a\u5229\u70b9\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f8b\u5916\u306b\u3088\u308b\u30a8\u30e9\u30fc\u51e6\u7406<\/li>\n\n\n\n<li>\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u306e\u691c\u51fa<\/li>\n\n\n\n<li>std::string\u3068\u306e\u76f4\u63a5\u7684\u306a\u4e92\u63db\u6027<\/li>\n\n\n\n<li>\u9032\u6570\u306e\u6307\u5b9a\u304c\u53ef\u80fd\uff08\u7b2c2\u5f15\u6570\u3067\u57fa\u6570\u3092\u6307\u5b9a\uff09<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-5\">\u6587\u5b57\u5217\u5909\u63db\u306e\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0\u624b\u6cd5<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u30e2\u30c0\u30f3C++\u3067\u306e\u63a8\u5968\u3055\u308c\u308b\u6587\u5b57\u5217\u5909\u63db\u30d1\u30bf\u30fc\u30f3\u3092\u4ee5\u4e0b\u306b\u793a\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u4f8b\u5916\u3092\u4f7f\u7528\u3057\u305f\u30ed\u30d0\u30b9\u30c8\u306a\u5b9f\u88c5\uff1a<\/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=\"\">#include &lt;iostream&gt;\n#include &lt;string&gt;\n#include &lt;optional&gt;\n\nstd::optional&lt;int&gt; safe_string_to_int(const std::string&amp; str) {\n    try {\n        size_t pos;\n        int result = std::stoi(str, &amp;pos);\n\n        \/\/ \u6587\u5b57\u5217\u5168\u4f53\u304c\u6570\u5024\u3068\u3057\u3066\u89e3\u91c8\u3055\u308c\u305f\u304b\u78ba\u8a8d\n        if (pos == str.length()) {\n            return result;\n        }\n        return std::nullopt;  \/\/ \u90e8\u5206\u7684\u306a\u5909\u63db\u306f\u5931\u6557\u3068\u3057\u3066\u6271\u3046\n    }\n    catch (const std::exception&amp;) {\n        return std::nullopt;\n    }\n}\n\n\/\/ \u4f7f\u7528\u4f8b\nvoid demonstrate_safe_conversion() {\n    std::vector&lt;std::string&gt; test_cases = {\n        \"123\",      \/\/ \u6b63\u5e38\u306a\u6570\u5024\n        \"456abc\",   \/\/ \u4e0d\u6b63\u306a\u6587\u5b57\u3092\u542b\u3080\n        \"789\",      \/\/ \u6b63\u5e38\u306a\u6570\u5024\n        \"abc\",      \/\/ \u7121\u52b9\u306a\u5165\u529b\n        \"2147483648\" \/\/ INT_MAX\u3092\u8d85\u3048\u308b\u5024\n    };\n\n    for (const auto&amp; test : test_cases) {\n        auto result = safe_string_to_int(test);\n        if (result) {\n            std::cout &lt;&lt; \"\u5909\u63db\u6210\u529f: \" &lt;&lt; *result &lt;&lt; std::endl;\n        } else {\n            std::cout &lt;&lt; \"\u5909\u63db\u5931\u6557: \" &lt;&lt; test &lt;&lt; std::endl;\n        }\n    }\n}<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>\u578b\u5b89\u5168\u306a\u6587\u5b57\u5217\u5909\u63db\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\uff1a<\/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=\"\">#include &lt;string&gt;\n#include &lt;type_traits&gt;\n#include &lt;limits&gt;\n\ntemplate&lt;typename T&gt;\nclass NumericConverter {\n    static_assert(std::is_arithmetic_v&lt;T&gt;, \"Type must be numeric\");\n\npublic:\n    struct ConversionResult {\n        bool success;\n        T value;\n        std::string error_message;\n    };\n\n    static ConversionResult convert(const std::string&amp; str) {\n        try {\n            size_t pos;\n            if constexpr (std::is_integral_v&lt;T&gt; &amp;&amp; std::is_signed_v&lt;T&gt;) {\n                long long temp = std::stoll(str, &amp;pos);\n                if (temp &lt; std::numeric_limits&lt;T&gt;::min() || \n                    temp &gt; std::numeric_limits&lt;T&gt;::max()) {\n                    return {false, T{}, \"Value out of range\"};\n                }\n                if (pos != str.length()) {\n                    return {false, T{}, \"Invalid characters in input\"};\n                }\n                return {true, static_cast&lt;T&gt;(temp), \"\"};\n            }\n            \/\/ \u4ed6\u306e\u6570\u5024\u578b\u306b\u5bfe\u3059\u308b\u5b9f\u88c5\u3082\u540c\u69d8\u306b\u8ffd\u52a0\u53ef\u80fd\n        }\n        catch (const std::invalid_argument&amp;) {\n            return {false, T{}, \"Invalid input format\"};\n        }\n        catch (const std::out_of_range&amp;) {\n            return {false, T{}, \"Value out of range\"};\n        }\n    }\n};<\/pre>\n\n\n\n<ol start=\"3\" class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u30b3\u30fc\u30c9\u3092\u4f7f\u7528\u3057\u305f\u30a2\u30d7\u30ed\u30fc\u30c1\uff1a<\/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=\"\">#include &lt;string&gt;\n#include &lt;system_error&gt;\n\nenum class ConversionError {\n    Success = 0,\n    InvalidFormat,\n    OutOfRange,\n    PartialConversion\n};\n\ntemplate&lt;typename T&gt;\nstruct ConversionResult {\n    T value;\n    ConversionError error;\n};\n\nConversionResult&lt;int&gt; string_to_int_with_error_code(const std::string&amp; str) {\n    try {\n        size_t pos;\n        int result = std::stoi(str, &amp;pos);\n\n        if (pos != str.length()) {\n            return {0, ConversionError::PartialConversion};\n        }\n\n        return {result, ConversionError::Success};\n    }\n    catch (const std::invalid_argument&amp;) {\n        return {0, ConversionError::InvalidFormat};\n    }\n    catch (const std::out_of_range&amp;) {\n        return {0, ConversionError::OutOfRange};\n    }\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u306f\u3001\u4ee5\u4e0b\u306e\u539f\u5247\u306b\u57fa\u3065\u3044\u3066\u3044\u307e\u3059\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u660e\u793a\u7684\u306a\u51e6\u7406<\/li>\n\n\n\n<li>\u578b\u5b89\u5168\u6027\u306e\u78ba\u4fdd<\/li>\n\n\n\n<li>\u7bc4\u56f2\u30c1\u30a7\u30c3\u30af\u306e\u5b9f\u65bd<\/li>\n\n\n\n<li>\u90e8\u5206\u7684\u306a\u5909\u63db\u306e\u691c\u51fa<\/li>\n\n\n\n<li>\u518d\u5229\u7528\u53ef\u80fd\u306a\u30b3\u30f3\u30dd\u30fc\u30cd\u30f3\u30c8\u5316<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u30a2\u30d7\u30ed\u30fc\u30c1\u3092\u4f7f\u7528\u3059\u308b\u3053\u3068\u3067\u3001\u6587\u5b57\u5217\u5909\u63db\u306e\u5b89\u5168\u6027\u3068\u4fdd\u5b88\u6027\u3092\u5927\u5e45\u306b\u5411\u4e0a\u3055\u305b\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-6\">atoi\u3092\u5b89\u5168\u306b\u4f7f\u7528\u3059\u308b7\u3064\u306e\u30b9\u30c6\u30c3\u30d7<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-7\">\u30b9\u30c6\u30c3\u30d71\uff1a\u5165\u529b\u5024\u306e\u59a5\u5f53\u6027\u691c\u8a3c<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u6587\u5b57\u5217\u3092\u6574\u6570\u306b\u5909\u63db\u3059\u308b\u524d\u306b\u3001\u5165\u529b\u5024\u306e\u59a5\u5f53\u6027\u3092\u78ba\u8a8d\u3059\u308b\u3053\u3068\u304c\u91cd\u8981\u3067\u3059\u3002\u4ee5\u4e0b\u306e\u5b9f\u88c5\u4f8b\u3067\u306f\u3001\u6587\u5b57\u5217\u304c\u6709\u52b9\u306a\u6574\u6570\u3092\u8868\u73fe\u3057\u3066\u3044\u308b\u304b\u3092\u691c\u8a3c\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;cctype&gt;\n#include &lt;string&gt;\n\nbool validateInput(const char* str) {\n    \/\/ null\u30c1\u30a7\u30c3\u30af\n    if (!str) return false;\n\n    \/\/ \u7a7a\u6587\u5b57\u5217\u30c1\u30a7\u30c3\u30af\n    if (*str == '\\0') return false;\n\n    \/\/ \u5148\u982d\u306e\u7a7a\u767d\u3092\u30b9\u30ad\u30c3\u30d7\n    while (isspace(*str)) str++;\n\n    \/\/ \u7b26\u53f7\u306e\u51e6\u7406\n    if (*str == '+' || *str == '-') str++;\n\n    \/\/ \u6570\u5b57\u304c\u5c11\u306a\u304f\u3068\u30821\u3064\u5fc5\u8981\n    bool hasDigit = false;\n    while (*str != '\\0') {\n        if (!isdigit(*str)) return false;\n        hasDigit = true;\n        str++;\n    }\n\n    return hasDigit;\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-8\">\u30b9\u30c6\u30c3\u30d72\uff1a\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u5bfe\u7b56<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u6574\u6570\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u3092\u9632\u3050\u305f\u3081\u3001\u6587\u5b57\u5217\u3092\u4e00\u65e6\u3088\u308a\u5927\u304d\u306a\u578b\u3067\u51e6\u7406\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;limits&gt;\n#include &lt;optional&gt;\n\nstd::optional&lt;int&gt; safeAtoi(const char* str) {\n    if (!validateInput(str)) {\n        return std::nullopt;\n    }\n\n    \/\/ strtoll\u3092\u4f7f\u7528\u3057\u3066\u9577\u3044\u6574\u6570\u3068\u3057\u3066\u89e3\u6790\n    char* endPtr;\n    long long value = strtoll(str, &amp;endPtr, 10);\n\n    \/\/ \u7bc4\u56f2\u30c1\u30a7\u30c3\u30af\n    if (value &lt; std::numeric_limits&lt;int&gt;::min() ||\n        value &gt; std::numeric_limits&lt;int&gt;::max()) {\n        return std::nullopt;\n    }\n\n    return static_cast&lt;int&gt;(value);\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-9\">\u30b9\u30c6\u30c3\u30d73\uff1a\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u9069\u5207\u306a\u51e6\u7406<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5909\u63db\u6642\u306e\u30a8\u30e9\u30fc\u72b6\u614b\u3092\u660e\u78ba\u306b\u8b58\u5225\u3057\u3001\u9069\u5207\u306b\u51e6\u7406\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=\"\">enum class ConversionError {\n    Success,\n    InvalidInput,\n    Overflow,\n    EmptyInput,\n    NullPointer\n};\n\nstruct ConversionResult {\n    int value;\n    ConversionError error;\n    std::string errorMessage;\n};\n\nConversionResult convertWithError(const char* str) {\n    if (!str) {\n        return {0, ConversionError::NullPointer, \"Input is null\"};\n    }\n\n    if (*str == '\\0') {\n        return {0, ConversionError::EmptyInput, \"Input is empty\"};\n    }\n\n    auto result = safeAtoi(str);\n    if (!result) {\n        return {0, ConversionError::InvalidInput, \"Invalid number format or overflow\"};\n    }\n\n    return {*result, ConversionError::Success, \"\"};\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-10\">\u30b9\u30c6\u30c3\u30d74\uff1a\u578b\u306e\u5b89\u5168\u6027\u78ba\u4fdd<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u7570\u306a\u308b\u6574\u6570\u578b\u306b\u5bfe\u5fdc\u3067\u304d\u308b\u578b\u5b89\u5168\u306a\u5909\u63db\u95a2\u6570\u3092\u5b9f\u88c5\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=\"\">template&lt;typename T&gt;\nclass NumericConverter {\n    static_assert(std::is_integral_v&lt;T&gt;, \"Only integral types are supported\");\n\npublic:\n    static std::optional&lt;T&gt; convert(const char* str) {\n        auto result = safeAtoi(str);\n        if (!result) {\n            return std::nullopt;\n        }\n\n        \/\/ \u578b\u306e\u7bc4\u56f2\u30c1\u30a7\u30c3\u30af\n        if (*result &lt; std::numeric_limits&lt;T&gt;::min() ||\n            *result &gt; std::numeric_limits&lt;T&gt;::max()) {\n            return std::nullopt;\n        }\n\n        return static_cast&lt;T&gt;(*result);\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-11\">\u30b9\u30c6\u30c3\u30d75\uff1a\u7570\u5e38\u5024\u306e\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u696d\u52d9\u30ed\u30b8\u30c3\u30af\u306b\u57fa\u3065\u3044\u305f\u5024\u306e\u691c\u8a3c\u3092\u5b9f\u88c5\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=\"\">template&lt;typename T&gt;\nclass ValueValidator {\npublic:\n    bool isValid(T value) {\n        \/\/ \u696d\u52d9\u30ed\u30b8\u30c3\u30af\u306b\u57fa\u3065\u304f\u691c\u8a3c\n        return checkRange(value) &amp;&amp; checkBusinessRules(value);\n    }\n\nprivate:\n    bool checkRange(T value) {\n        \/\/ \u4f8b\uff1a\u6b63\u306e\u5024\u306e\u307f\u3092\u8a31\u53ef\n        return value &gt; 0;\n    }\n\n    bool checkBusinessRules(T value) {\n        \/\/ \u4f8b\uff1a\u7279\u5b9a\u306e\u7bc4\u56f2\u5185\u306e\u5024\u306e\u307f\u3092\u8a31\u53ef\n        return value &lt;= 1000; \/\/ \u696d\u52d9\u8981\u4ef6\u306b\u5fdc\u3058\u3066\u8abf\u6574\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-12\">\u30b9\u30c6\u30c3\u30d76\uff1a\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u306e\u6700\u9069\u5316<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5\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=\"\">class FastIntConverter {\npublic:\n    static int convert(const char* str) {\n        int result = 0;\n        bool negative = false;\n\n        \/\/ \u7a7a\u767d\u3092\u30b9\u30ad\u30c3\u30d7\n        while (isspace(*str)) str++;\n\n        \/\/ \u7b26\u53f7\u306e\u51e6\u7406\n        if (*str == '-') {\n            negative = true;\n            str++;\n        } else if (*str == '+') {\n            str++;\n        }\n\n        \/\/ \u6570\u5b57\u306e\u51e6\u7406\uff08\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u30c1\u30a7\u30c3\u30af\u4ed8\u304d\uff09\n        while (isdigit(*str)) {\n            int digit = *str - '0';\n\n            \/\/ \u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u30c1\u30a7\u30c3\u30af\n            if (result &gt; INT_MAX \/ 10 ||\n                (result == INT_MAX \/ 10 &amp;&amp; digit &gt; INT_MAX % 10)) {\n                return negative ? INT_MIN : INT_MAX;\n            }\n\n            result = result * 10 + digit;\n            str++;\n        }\n\n        return negative ? -result : result;\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-13\">\u30b9\u30c6\u30c3\u30d77\uff1a\u5358\u4f53\u30c6\u30b9\u30c8\u306e\u5b9f\u88c5<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5909\u63db\u30ed\u30b8\u30c3\u30af\u306e\u4fe1\u983c\u6027\u3092\u78ba\u4fdd\u3059\u308b\u305f\u3081\u306e\u30c6\u30b9\u30c8\u30b1\u30fc\u30b9\u3092\u5b9f\u88c5\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;cassert&gt;\n\nvoid testStringConversion() {\n    \/\/ \u57fa\u672c\u7684\u306a\u5909\u63db\u306e\u30c6\u30b9\u30c8\n    assert(*safeAtoi(\"123\") == 123);\n    assert(*safeAtoi(\"-456\") == -456);\n\n    \/\/ \u30a8\u30e9\u30fc\u30b1\u30fc\u30b9\u306e\u30c6\u30b9\u30c8\n    assert(!safeAtoi(\"abc\").has_value());\n    assert(!safeAtoi(\"\").has_value());\n    assert(!safeAtoi(nullptr).has_value());\n\n    \/\/ \u5883\u754c\u5024\u306e\u30c6\u30b9\u30c8\n    assert(!safeAtoi(\"2147483648\").has_value());  \/\/ INT_MAX + 1\n    assert(!safeAtoi(\"-2147483649\").has_value()); \/\/ INT_MIN - 1\n\n    \/\/ \u578b\u5909\u63db\u306e\u30c6\u30b9\u30c8\n    auto shortValue = NumericConverter&lt;short&gt;::convert(\"12345\");\n    assert(shortValue.has_value() &amp;&amp; *shortValue == 12345);\n\n    \/\/ \u5024\u306e\u691c\u8a3c\u30c6\u30b9\u30c8\n    ValueValidator&lt;int&gt; validator;\n    assert(validator.isValid(500));\n    assert(!validator.isValid(-1));\n    assert(!validator.isValid(1001));\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e7\u3064\u306e\u30b9\u30c6\u30c3\u30d7\u3092\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001\u4ee5\u4e0b\u306e\u5229\u70b9\u304c\u5f97\u3089\u308c\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5165\u529b\u5024\u306e\u5b89\u5168\u6027\u78ba\u4fdd<\/li>\n\n\n\n<li>\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u306e\u9632\u6b62<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u660e\u78ba\u306a\u8b58\u5225\u3068\u51e6\u7406<\/li>\n\n\n\n<li>\u578b\u5b89\u5168\u6027\u306e\u4fdd\u8a3c<\/li>\n\n\n\n<li>\u30d3\u30b8\u30cd\u30b9\u30ed\u30b8\u30c3\u30af\u306b\u57fa\u3065\u304f\u5024\u306e\u691c\u8a3c<\/li>\n\n\n\n<li>\u6700\u9069\u5316\u3055\u308c\u305f\u5909\u63db\u51e6\u7406<\/li>\n\n\n\n<li>\u30c6\u30b9\u30c8\u306b\u3088\u308b\u54c1\u8cea\u4fdd\u8a3c<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u306e\u30a2\u30d7\u30ed\u30fc\u30c1\u3092\u63a1\u7528\u3059\u308b\u3053\u3068\u3067\u3001<code>atoi<\/code>\u306e\u4f7f\u7528\u306b\u95a2\u9023\u3059\u308b\u30ea\u30b9\u30af\u3092\u6700\u5c0f\u9650\u306b\u6291\u3048\u306a\u304c\u3089\u3001\u5805\u7262\u306a\u6587\u5b57\u5217\u5909\u63db\u6a5f\u80fd\u3092\u5b9f\u73fe\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-14\">\u5b9f\u8df5\u7684\u306a\u30b3\u30fc\u30c9\u4f8b\u3067\u5b66\u3076atoi<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-15\">\u30ec\u30ac\u30b7\u30fc\u30b3\u30fc\u30c9\u306e\u30e2\u30c0\u30f3\u5316\u4e8b\u4f8b<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u4ee5\u4e0b\u306b\u3001\u5178\u578b\u7684\u306a\u30ec\u30ac\u30b7\u30fc\u30b3\u30fc\u30c9\u3068\u305d\u306e\u30e2\u30c0\u30f3\u5316\u306e\u4f8b\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=\"\">\/\/ \u30ec\u30ac\u30b7\u30fc\u30b3\u30fc\u30c9\u306e\u4f8b\n#include &lt;cstdlib&gt;\n#include &lt;cstring&gt;\n\n\/\/ \u554f\u984c\u306e\u3042\u308b\u5b9f\u88c5\nvoid legacy_process_data(const char* input) {\n    \/\/ \u5371\u967a\u306a\u5b9f\u88c5\n    int value = atoi(input);\n    if (value == 0) {\n        \/\/ 0\u304c\u6b63\u5e38\u5024\u306a\u306e\u304b\u3001\u30a8\u30e9\u30fc\u306a\u306e\u304b\u5224\u5225\u3067\u304d\u306a\u3044\n        return;\n    }\n    process_value(value);\n}\n\n\/\/ \u30e2\u30c0\u30f3\u5316\u3055\u308c\u305f\u5b9f\u88c5\n#include &lt;string&gt;\n#include &lt;optional&gt;\n#include &lt;charconv&gt;\n\nclass ModernNumberParser {\npublic:\n    static std::optional&lt;int&gt; parse(std::string_view str) {\n        int value;\n        auto result = std::from_chars(str.data(), str.data() + str.size(), value);\n\n        if (result.ec == std::errc::invalid_argument || \n            result.ec == std::errc::result_out_of_range) {\n            return std::nullopt;\n        }\n\n        \/\/ \u6587\u5b57\u5217\u5168\u4f53\u304c\u89e3\u6790\u3055\u308c\u305f\u304b\u78ba\u8a8d\n        if (result.ptr != str.data() + str.size()) {\n            return std::nullopt;\n        }\n\n        return value;\n    }\n};\n\nvoid modern_process_data(std::string_view input) {\n    auto result = ModernNumberParser::parse(input);\n    if (!result) {\n        handle_error(\"Invalid input\");\n        return;\n    }\n    process_value(*result);\n}<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-16\">\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3092\u8003\u616e\u3057\u305f\u5b9f\u88c5\u4f8b<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5927\u91cf\u306e\u30c7\u30fc\u30bf\u3092\u51e6\u7406\u3059\u308b\u5834\u5408\u306e\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316\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=\"\">#include &lt;vector&gt;\n#include &lt;string_view&gt;\n#include &lt;thread&gt;\n#include &lt;future&gt;\n\nclass BatchNumberConverter {\npublic:\n    struct ConversionResult {\n        std::vector&lt;int&gt; values;\n        std::vector&lt;size_t&gt; error_indices;\n    };\n\n    \/\/ \u4e26\u5217\u51e6\u7406\u3092\u6d3b\u7528\u3057\u305f\u9ad8\u901f\u306a\u5909\u63db\n    static ConversionResult convert_batch(const std::vector&lt;std::string_view&gt;&amp; inputs,\n                                        size_t thread_count = std::thread::hardware_concurrency()) {\n        ConversionResult result;\n        result.values.resize(inputs.size());\n\n        \/\/ \u5165\u529b\u3092\u8907\u6570\u306e\u30b9\u30ec\u30c3\u30c9\u306b\u5206\u5272\n        std::vector&lt;std::future&lt;void&gt;&gt; futures;\n        size_t chunk_size = (inputs.size() + thread_count - 1) \/ thread_count;\n\n        std::mutex error_mutex;\n\n        for (size_t i = 0; i &lt; thread_count; ++i) {\n            size_t start = i * chunk_size;\n            size_t end = std::min(start + chunk_size, inputs.size());\n\n            if (start &gt;= inputs.size()) break;\n\n            futures.push_back(std::async(std::launch::async, \n                [&amp;, start, end]() {\n                    std::vector&lt;size_t&gt; local_errors;\n\n                    for (size_t j = start; j &lt; end; ++j) {\n                        auto parsed = ModernNumberParser::parse(inputs[j]);\n                        if (parsed) {\n                            result.values[j] = *parsed;\n                        } else {\n                            local_errors.push_back(j);\n                        }\n                    }\n\n                    \/\/ \u30a8\u30e9\u30fc\u30a4\u30f3\u30c7\u30c3\u30af\u30b9\u306e\u8ffd\u52a0\n                    if (!local_errors.empty()) {\n                        std::lock_guard&lt;std::mutex&gt; lock(error_mutex);\n                        result.error_indices.insert(\n                            result.error_indices.end(),\n                            local_errors.begin(),\n                            local_errors.end()\n                        );\n                    }\n                }\n            ));\n        }\n\n        \/\/ \u5168\u3066\u306e\u30b9\u30ec\u30c3\u30c9\u306e\u5b8c\u4e86\u3092\u5f85\u6a5f\n        for (auto&amp; future : futures) {\n            future.wait();\n        }\n\n        return result;\n    }\n};\n\n\/\/ \u4f7f\u7528\u4f8b\nvoid demonstrate_batch_processing() {\n    std::vector&lt;std::string_view&gt; inputs = {\n        \"123\", \"456\", \"invalid\", \"789\", \"1000\"\n    };\n\n    auto result = BatchNumberConverter::convert_batch(inputs);\n\n    \/\/ \u5909\u63db\u7d50\u679c\u306e\u51e6\u7406\n    for (size_t i = 0; i &lt; inputs.size(); ++i) {\n        if (std::find(result.error_indices.begin(),\n                     result.error_indices.end(), i) == result.error_indices.end()) {\n            std::cout &lt;&lt; \"\u6210\u529f: \" &lt;&lt; inputs[i] &lt;&lt; \" -&gt; \" &lt;&lt; result.values[i] &lt;&lt; std::endl;\n        } else {\n            std::cout &lt;&lt; \"\u30a8\u30e9\u30fc: \" &lt;&lt; inputs[i] &lt;&lt; std::endl;\n        }\n    }\n}\n\n\/\/ \u6587\u5b57\u5217\u30d7\u30fc\u30eb\u3092\u4f7f\u7528\u3057\u305f\u30e1\u30e2\u30ea\u6700\u9069\u5316\nclass StringNumberCache {\n    struct CacheEntry {\n        int value;\n        bool is_valid;\n    };\n\n    std::unordered_map&lt;std::string_view, CacheEntry&gt; cache_;\n    std::vector&lt;std::string&gt; string_pool_;\n\npublic:\n    std::optional&lt;int&gt; get_or_convert(std::string_view input) {\n        auto it = cache_.find(input);\n        if (it != cache_.end()) {\n            return it-&gt;second.is_valid ? std::optional&lt;int&gt;{it-&gt;second.value}\n                                     : std::nullopt;\n        }\n\n        auto result = ModernNumberParser::parse(input);\n\n        \/\/ \u6587\u5b57\u5217\u3092\u30d7\u30fc\u30eb\u306b\u4fdd\u5b58\n        string_pool_.push_back(std::string(input));\n        std::string_view stored_view = string_pool_.back();\n\n        \/\/ \u30ad\u30e3\u30c3\u30b7\u30e5\u306b\u7d50\u679c\u3092\u4fdd\u5b58\n        cache_[stored_view] = {\n            result ? *result : 0,\n            result.has_value()\n        };\n\n        return result;\n    }\n\n    void clear() {\n        cache_.clear();\n        string_pool_.clear();\n    }\n};<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u5b9f\u88c5\u4f8b\u306f\u4ee5\u4e0b\u306e\u7279\u5fb4\u3092\u6301\u3063\u3066\u3044\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30ec\u30ac\u30b7\u30fc\u30b3\u30fc\u30c9\u306e\u30e2\u30c0\u30f3\u5316<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>std::from_chars\u306e\u4f7f\u7528\u306b\u3088\u308b\u52b9\u7387\u7684\u306a\u5909\u63db<\/li>\n\n\n\n<li>\u660e\u78ba\u306a\u30a8\u30e9\u30fc\u30cf\u30f3\u30c9\u30ea\u30f3\u30b0<\/li>\n\n\n\n<li>\u578b\u5b89\u5168\u6027\u306e\u78ba\u4fdd<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4e26\u5217\u51e6\u7406\u306b\u3088\u308b\u5927\u91cf\u30c7\u30fc\u30bf\u306e\u9ad8\u901f\u51e6\u7406<\/li>\n\n\n\n<li>\u30e1\u30e2\u30ea\u52b9\u7387\u3092\u8003\u616e\u3057\u305f\u6587\u5b57\u5217\u30d7\u30fc\u30eb<\/li>\n\n\n\n<li>\u30ad\u30e3\u30c3\u30b7\u30e5\u306b\u3088\u308b\u91cd\u8907\u5909\u63db\u306e\u56de\u907f<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u6539\u5584<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u8a73\u7d30\u306a\u30a8\u30e9\u30fc\u60c5\u5831\u306e\u63d0\u4f9b<\/li>\n\n\n\n<li>\u30d0\u30c3\u30c1\u51e6\u7406\u6642\u306e\u30a8\u30e9\u30fc\u8ffd\u8de1<\/li>\n\n\n\n<li>\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u5b9f\u88c5<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u5b9f\u88c5\u30d1\u30bf\u30fc\u30f3\u306f\u3001\u5b9f\u969b\u306e\u696d\u52d9\u30b7\u30b9\u30c6\u30e0\u3067\u3088\u304f\u906d\u9047\u3059\u308b\u8981\u4ef6\u306b\u5bfe\u5fdc\u3067\u304d\u308b\u3088\u3046\u306b\u8a2d\u8a08\u3055\u308c\u3066\u3044\u307e\u3059\u3002\u7279\u306b\u5927\u91cf\u30c7\u30fc\u30bf\u51e6\u7406\u3084\u9ad8\u6027\u80fd\u304c\u6c42\u3081\u3089\u308c\u308b\u5834\u9762\u3067\u6709\u7528\u3067\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-17\">\u3088\u304f\u3042\u308batoi\u95a2\u9023\u306e\u30d0\u30b0\u3068\u5bfe\u7b56<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-18\">\u30e1\u30e2\u30ea\u7834\u58ca\u3092\u9632\u3050\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">atoi\u306e\u4f7f\u7528\u306b\u95a2\u9023\u3059\u308b\u30e1\u30e2\u30ea\u7834\u58ca\u306e\u4e3b\u306a\u539f\u56e0\u3068\u3001\u305d\u308c\u3092\u9632\u3050\u305f\u3081\u306e\u5b9f\u88c5\u30c6\u30af\u30cb\u30c3\u30af\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=\"\">#include &lt;memory&gt;\n#include &lt;cstring&gt;\n#include &lt;stdexcept&gt;\n\nclass SafeStringConverter {\npublic:\n    \/\/ \u30e1\u30e2\u30ea\u5b89\u5168\u306a\u6587\u5b57\u5217\u51e6\u7406\n    static int convertSafely(const char* input, size_t maxLength = 1024) {\n        if (!input) {\n            throw std::invalid_argument(\"Null pointer provided\");\n        }\n\n        \/\/ \u5165\u529b\u9577\u306e\u30c1\u30a7\u30c3\u30af\n        size_t inputLength = strlen(input);\n        if (inputLength &gt; maxLength) {\n            throw std::length_error(\"Input string too long\");\n        }\n\n        \/\/ \u5b89\u5168\u306a\u30d0\u30c3\u30d5\u30a1\u3078\u306e\u30b3\u30d4\u30fc\n        std::unique_ptr&lt;char[]&gt; safeBuffer = std::make_unique&lt;char[]&gt;(maxLength + 1);\n        strncpy(safeBuffer.get(), input, maxLength);\n        safeBuffer[maxLength] = '\\0';  \/\/ \u5fc5\u305a\u7d42\u7aef\n\n        \/\/ \u4e0d\u6b63\u306a\u6587\u5b57\u306e\u30c1\u30a7\u30c3\u30af\n        for (size_t i = 0; i &lt; inputLength; i++) {\n            char c = safeBuffer[i];\n            if (!isspace(c) &amp;&amp; !isdigit(c) &amp;&amp; c != '-' &amp;&amp; c != '+') {\n                throw std::invalid_argument(\"Invalid character in input\");\n            }\n        }\n\n        return std::atoi(safeBuffer.get());\n    }\n};\n\n\/\/ \u30d0\u30c3\u30d5\u30a1\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u3092\u9632\u3050\u6587\u5b57\u5217\u51e6\u7406\u30af\u30e9\u30b9\nclass BoundedStringProcessor {\n    std::vector&lt;char&gt; buffer_;\n    size_t maxSize_;\n\npublic:\n    explicit BoundedStringProcessor(size_t maxSize) \n        : buffer_(maxSize + 1), maxSize_(maxSize) {}\n\n    int processString(const char* input) {\n        if (!input) return 0;\n\n        size_t inputLen = strlen(input);\n        if (inputLen &gt; maxSize_) {\n            throw std::length_error(\"Input exceeds maximum allowed size\");\n        }\n\n        \/\/ \u5b89\u5168\u306a\u30b3\u30d4\u30fc\n        std::copy_n(input, inputLen, buffer_.begin());\n        buffer_[inputLen] = '\\0';\n\n        return std::atoi(buffer_.data());\n    }\n};<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u3088\u304f\u3042\u308b\u554f\u984c\u3068\u5bfe\u7b56\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u5883\u754c\u30c1\u30a7\u30c3\u30af\u306e\u6b20\u5982<\/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=\"\">class BoundaryCheckConverter {\npublic:\n    static std::optional&lt;int&gt; convert(const char* input, size_t maxDigits = 10) {\n        if (!input) return std::nullopt;\n\n        \/\/ \u6570\u5b57\u306e\u6841\u6570\u3092\u30ab\u30a6\u30f3\u30c8\n        size_t digitCount = 0;\n        bool hasSign = (input[0] == '-' || input[0] == '+');\n        const char* ptr = hasSign ? input + 1 : input;\n\n        while (*ptr) {\n            if (!std::isdigit(*ptr)) return std::nullopt;\n            digitCount++;\n            if (digitCount &gt; maxDigits) return std::nullopt;\n            ptr++;\n        }\n\n        try {\n            return std::stoi(input);\n        } catch (...) {\n            return std::nullopt;\n        }\n    }\n};<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>\u30e1\u30e2\u30ea\u30ea\u30fc\u30af\u306e\u9632\u6b62<\/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=\"\">class ResourceSafeConverter {\n    class ScopedBuffer {\n        std::unique_ptr&lt;char[]&gt; buffer_;\n    public:\n        explicit ScopedBuffer(size_t size) : buffer_(std::make_unique&lt;char[]&gt;(size)) {}\n        char* get() { return buffer_.get(); }\n    };\n\npublic:\n    static int convertWithResource(const std::string&amp; input) {\n        ScopedBuffer buffer(input.length() + 1);\n        std::strcpy(buffer.get(), input.c_str());\n        return std::atoi(buffer.get());\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-19\">\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306e\u5b89\u5168\u306a\u4f7f\u7528\u6cd5<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u74b0\u5883\u3067\u306eatoi\u4f7f\u7528\u306b\u95a2\u3059\u308b\u554f\u984c\u3068\u5bfe\u7b56\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;mutex&gt;\n#include &lt;shared_mutex&gt;\n#include &lt;thread&gt;\n#include &lt;unordered_map&gt;\n\n\/\/ \u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u6570\u5024\u5909\u63db\u30ad\u30e3\u30c3\u30b7\u30e5\nclass ThreadSafeNumberCache {\n    mutable std::shared_mutex mutex_;\n    std::unordered_map&lt;std::string, int&gt; cache_;\n\npublic:\n    std::optional&lt;int&gt; getOrConvert(const std::string&amp; input) {\n        \/\/ \u8aad\u307f\u53d6\u308a\u7528\u30ed\u30c3\u30af\n        {\n            std::shared_lock&lt;std::shared_mutex&gt; readLock(mutex_);\n            auto it = cache_.find(input);\n            if (it != cache_.end()) {\n                return it-&gt;second;\n            }\n        }\n\n        \/\/ \u5909\u63db\u51e6\u7406\n        int value;\n        try {\n            value = std::stoi(input);\n        } catch (...) {\n            return std::nullopt;\n        }\n\n        \/\/ \u66f8\u304d\u8fbc\u307f\u7528\u30ed\u30c3\u30af\n        {\n            std::unique_lock&lt;std::shared_mutex&gt; writeLock(mutex_);\n            cache_[input] = value;\n        }\n\n        return value;\n    }\n\n    void clear() {\n        std::unique_lock&lt;std::shared_mutex&gt; lock(mutex_);\n        cache_.clear();\n    }\n};\n\n\/\/ \u30b9\u30ec\u30c3\u30c9\u30ed\u30fc\u30ab\u30eb\u30b9\u30c8\u30ec\u30fc\u30b8\u3092\u6d3b\u7528\u3057\u305f\u5b9f\u88c5\nclass ThreadLocalConverter {\n    static thread_local BoundedStringProcessor processor;\n\npublic:\n    static int convert(const char* input) {\n        return processor.processString(input);\n    }\n};\n\nthread_local BoundedStringProcessor ThreadLocalConverter::processor(1024);\n\n\/\/ \u30b9\u30ec\u30c3\u30c9\u30d7\u30fc\u30eb\u5bfe\u5fdc\u306e\u6570\u5024\u5909\u63db\u5668\nclass ThreadPoolNumberConverter {\n    ThreadSafeNumberCache cache_;\n    std::vector&lt;std::thread&gt; workers_;\n    std::mutex queueMutex_;\n    std::condition_variable condition_;\n    std::queue&lt;std::pair&lt;std::string, std::promise&lt;int&gt;&gt;&gt; tasks_;\n    bool stopping_ = false;\n\npublic:\n    explicit ThreadPoolNumberConverter(size_t threadCount = std::thread::hardware_concurrency()) {\n        for (size_t i = 0; i &lt; threadCount; ++i) {\n            workers_.emplace_back([this] { workerFunction(); });\n        }\n    }\n\n    std::future&lt;int&gt; convertAsync(const std::string&amp; input) {\n        std::promise&lt;int&gt; promise;\n        std::future&lt;int&gt; future = promise.get_future();\n\n        {\n            std::lock_guard&lt;std::mutex&gt; lock(queueMutex_);\n            tasks_.push({input, std::move(promise)});\n        }\n        condition_.notify_one();\n        return future;\n    }\n\n    ~ThreadPoolNumberConverter() {\n        {\n            std::lock_guard&lt;std::mutex&gt; lock(queueMutex_);\n            stopping_ = true;\n        }\n        condition_.notify_all();\n        for (auto&amp; worker : workers_) {\n            worker.join();\n        }\n    }\n\nprivate:\n    void workerFunction() {\n        while (true) {\n            std::pair&lt;std::string, std::promise&lt;int&gt;&gt; task;\n            {\n                std::unique_lock&lt;std::mutex&gt; lock(queueMutex_);\n                condition_.wait(lock, [this] {\n                    return stopping_ || !tasks_.empty();\n                });\n\n                if (stopping_ &amp;&amp; tasks_.empty()) {\n                    return;\n                }\n\n                task = std::move(tasks_.front());\n                tasks_.pop();\n            }\n\n            try {\n                auto result = cache_.getOrConvert(task.first);\n                if (result) {\n                    task.second.set_value(*result);\n                } else {\n                    task.second.set_exception(\n                        std::make_exception_ptr(std::invalid_argument(\"Conversion failed\"))\n                    );\n                }\n            } catch (...) {\n                task.second.set_exception(std::current_exception());\n            }\n        }\n    }\n};<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u5b9f\u88c5\u306f\u4ee5\u4e0b\u306e\u554f\u984c\u306b\u5bfe\u3059\u308b\u5bfe\u7b56\u3092\u63d0\u4f9b\u3057\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30e1\u30e2\u30ea\u5b89\u5168\u6027\u306e\u78ba\u4fdd<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30d0\u30c3\u30d5\u30a1\u30aa\u30fc\u30d0\u30fc\u30d5\u30ed\u30fc\u9632\u6b62<\/li>\n\n\n\n<li>\u30ea\u30bd\u30fc\u30b9\u30ea\u30fc\u30af\u9632\u6b62<\/li>\n\n\n\n<li>\u9069\u5207\u306a\u5883\u754c\u30c1\u30a7\u30c3\u30af<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30de\u30eb\u30c1\u30b9\u30ec\u30c3\u30c9\u5bfe\u5fdc<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30b9\u30ec\u30c3\u30c9\u30bb\u30fc\u30d5\u306a\u30ad\u30e3\u30c3\u30b7\u30e5<\/li>\n\n\n\n<li>\u30b9\u30ec\u30c3\u30c9\u30ed\u30fc\u30ab\u30eb\u30b9\u30c8\u30ec\u30fc\u30b8\u306e\u6d3b\u7528<\/li>\n\n\n\n<li>\u52b9\u7387\u7684\u306a\u30b9\u30ec\u30c3\u30c9\u30d7\u30fc\u30eb\u5b9f\u88c5<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u5f37\u5316<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f8b\u5916\u306e\u9069\u5207\u306a\u51e6\u7406<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u72b6\u614b\u306e\u4f1d\u64ad<\/li>\n\n\n\n<li>\u30ea\u30bd\u30fc\u30b9\u306e\u78ba\u5b9f\u306a\u89e3\u653e<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u5bfe\u7b56\u3092\u9069\u5207\u306b\u5b9f\u88c5\u3059\u308b\u3053\u3068\u3067\u3001atoi\u306e\u4f7f\u7528\u306b\u95a2\u9023\u3059\u308b\u591a\u304f\u306e\u4e00\u822c\u7684\u306a\u554f\u984c\u3092\u56de\u907f\u3067\u304d\u307e\u3059\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"i-20\">\u6b21\u306e\u30b9\u30c6\u30c3\u30d7\uff1a\u3055\u3089\u306a\u308b\u5b66\u7fd2\u30ea\u30bd\u30fc\u30b9<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-21\">\u63a8\u5968\u3055\u308c\u308b\u4ee3\u66ff\u95a2\u6570\u3068\u30e9\u30a4\u30d6\u30e9\u30ea<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u30e2\u30c0\u30f3C++\u3067\u306e\u6587\u5b57\u5217\u5909\u63db\u306b\u306f\u3001\u4ee5\u4e0b\u306e\u4ee3\u66ff\u624b\u6bb5\u304c\u63a8\u5968\u3055\u308c\u307e\u3059\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>std::from_chars<\/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=\"\">#include &lt;charconv&gt;\n#include &lt;system_error&gt;\n\nclass ModernConverter {\npublic:\n    static std::optional&lt;int&gt; fromChars(std::string_view str) {\n        int value;\n        auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value);\n\n        if (ec == std::errc{} &amp;&amp; ptr == str.data() + str.size()) {\n            return value;\n        }\n        return std::nullopt;\n    }\n\n    \/\/ 16\u9032\u6570\u5909\u63db\u306e\u4f8b\n    static std::optional&lt;int&gt; fromHex(std::string_view str) {\n        int value;\n        auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value, 16);\n\n        if (ec == std::errc{} &amp;&amp; ptr == str.data() + str.size()) {\n            return value;\n        }\n        return std::nullopt;\n    }\n};\n\n\/\/ \u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6bd4\u8f03\u7528\u306e\u30d9\u30f3\u30c1\u30de\u30fc\u30af\u95a2\u6570\nvoid benchmark_conversions() {\n    const char* test_number = \"12345\";\n\n    \/\/ \u5f93\u6765\u306e\u65b9\u6cd5\n    auto start1 = std::chrono::high_resolution_clock::now();\n    int result1 = std::atoi(test_number);\n    auto end1 = std::chrono::high_resolution_clock::now();\n\n    \/\/ from_chars\u3092\u4f7f\u7528\n    auto start2 = std::chrono::high_resolution_clock::now();\n    int value;\n    std::from_chars(test_number, test_number + strlen(test_number), value);\n    auto end2 = std::chrono::high_resolution_clock::now();\n\n    std::cout &lt;&lt; \"atoi time: \" \n              &lt;&lt; std::chrono::duration_cast&lt;std::chrono::nanoseconds&gt;(end1 - start1).count() \n              &lt;&lt; \"ns\\n\";\n    std::cout &lt;&lt; \"from_chars time: \" \n              &lt;&lt; std::chrono::duration_cast&lt;std::chrono::nanoseconds&gt;(end2 - start2).count() \n              &lt;&lt; \"ns\\n\";\n}<\/pre>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>std::stringstream<\/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=\"\">#include &lt;sstream&gt;\n#include &lt;iomanip&gt;\n\nclass StreamConverter {\npublic:\n    \/\/ \u69d8\u3005\u306a\u57fa\u6570\u3067\u306e\u5909\u63db\u3092\u30b5\u30dd\u30fc\u30c8\n    template&lt;typename T&gt;\n    static std::optional&lt;T&gt; convert(const std::string&amp; str, int base = 10) {\n        std::istringstream iss(str);\n\n        if (base == 16) {\n            iss &gt;&gt; std::hex;\n        } else if (base == 8) {\n            iss &gt;&gt; std::oct;\n        }\n\n        T value;\n        if (iss &gt;&gt; value &amp;&amp; iss.eof()) {\n            return value;\n        }\n        return std::nullopt;\n    }\n\n    \/\/ \u66f8\u5f0f\u5316\u3055\u308c\u305f\u51fa\u529b\u306e\u30b5\u30dd\u30fc\u30c8\n    static std::string format(int value, int width = 0, char fill = '0') {\n        std::ostringstream oss;\n        oss &lt;&lt; std::setw(width) &lt;&lt; std::setfill(fill) &lt;&lt; value;\n        return oss.str();\n    }\n};<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"i-22\">\u95a2\u9023\u3059\u308bC++\u6a19\u6e96\u30e9\u30a4\u30d6\u30e9\u30ea\u306e\u6a5f\u80fd<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u6570\u5024\u5909\u63db\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3<\/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=\"\">#include &lt;string&gt;\n#include &lt;optional&gt;\n#include &lt;variant&gt;\n\n\/\/ \u6c4e\u7528\u6570\u5024\u5909\u63db\u30e6\u30fc\u30c6\u30a3\u30ea\u30c6\u30a3\nclass NumericUtils {\npublic:\n    \/\/ \u69d8\u3005\u306a\u6570\u5024\u578b\u3092\u30b5\u30dd\u30fc\u30c8\u3059\u308b\u5909\u63db\n    template&lt;typename T&gt;\n    static std::optional&lt;T&gt; parse(const std::string&amp; str) {\n        try {\n            if constexpr (std::is_same_v&lt;T, int&gt;) {\n                return std::stoi(str);\n            } else if constexpr (std::is_same_v&lt;T, long&gt;) {\n                return std::stol(str);\n            } else if constexpr (std::is_same_v&lt;T, long long&gt;) {\n                return std::stoll(str);\n            } else if constexpr (std::is_same_v&lt;T, unsigned long&gt;) {\n                return std::stoul(str);\n            } else if constexpr (std::is_same_v&lt;T, unsigned long long&gt;) {\n                return std::stoull(str);\n            } else if constexpr (std::is_same_v&lt;T, float&gt;) {\n                return std::stof(str);\n            } else if constexpr (std::is_same_v&lt;T, double&gt;) {\n                return std::stod(str);\n            }\n        } catch (...) {\n            return std::nullopt;\n        }\n        return std::nullopt;\n    }\n\n    \/\/ \u4efb\u610f\u306e\u6570\u5024\u578b\u3092\u6587\u5b57\u5217\u306b\u5909\u63db\n    template&lt;typename T&gt;\n    static std::string toString(T value) {\n        if constexpr (std::is_arithmetic_v&lt;T&gt;) {\n            return std::to_string(value);\n        }\n        return \"\";\n    }\n};\n\n\/\/ \u578b\u5b89\u5168\u306a\u6570\u5024\u64cd\u4f5c\nclass SafeNumber {\n    std::variant&lt;int, long, long long, \n                unsigned long, unsigned long long,\n                float, double&gt; value_;\n\npublic:\n    template&lt;typename T&gt;\n    static SafeNumber create(const std::string&amp; str) {\n        auto result = NumericUtils::parse&lt;T&gt;(str);\n        if (result) {\n            return SafeNumber(*result);\n        }\n        throw std::invalid_argument(\"Conversion failed\");\n    }\n\n    template&lt;typename T&gt;\n    std::optional&lt;T&gt; as() const {\n        try {\n            return std::get&lt;T&gt;(value_);\n        } catch (const std::bad_variant_access&amp;) {\n            return std::nullopt;\n        }\n    }\n};<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u6b21\u306b\u5b66\u3076\u3079\u304d\u91cd\u8981\u306a\u30c8\u30d4\u30c3\u30af\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6700\u9069\u5316<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>std::from_chars\u306e\u5185\u90e8\u5b9f\u88c5<\/li>\n\n\n\n<li>SSE\/AVX\u547d\u4ee4\u3092\u4f7f\u7528\u3057\u305f\u9ad8\u901f\u306a\u6587\u5b57\u5217\u51e6\u7406<\/li>\n\n\n\n<li>\u30e1\u30e2\u30ea\u30a2\u30e9\u30a4\u30e1\u30f3\u30c8\u3068\u30ad\u30e3\u30c3\u30b7\u30e5\u6700\u9069\u5316<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30a8\u30e9\u30fc\u51e6\u7406\u306e\u9ad8\u5ea6\u306a\u30c6\u30af\u30cb\u30c3\u30af<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>std::expected\uff08C++23\uff09\u306e\u6d3b\u7528<\/li>\n\n\n\n<li>\u30a8\u30e9\u30fc\u5831\u544a\u30b7\u30b9\u30c6\u30e0\u306e\u8a2d\u8a08<\/li>\n\n\n\n<li>\u30ed\u30b0\u6a5f\u80fd\u3068\u306e\u7d71\u5408<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u56fd\u969b\u5316\u5bfe\u5fdc<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30ed\u30b1\u30fc\u30eb\u4f9d\u5b58\u306e\u6570\u5024\u5909\u63db<\/li>\n\n\n\n<li>Unicode\u6587\u5b57\u5217\u306e\u51e6\u7406<\/li>\n\n\n\n<li>\u591a\u8a00\u8a9e\u74b0\u5883\u3067\u306e\u6570\u5024\u30d5\u30a9\u30fc\u30de\u30c3\u30c8<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u63a8\u5968\u3055\u308c\u308b\u5b66\u7fd2\u30ea\u30bd\u30fc\u30b9\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30e2\u30c0\u30f3C++\u306e\u6a5f\u80fd<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>C++17\u306estd::from_chars<\/li>\n\n\n\n<li>C++20\u306e\u5236\u7d04\u3068\u30b3\u30f3\u30bb\u30d7\u30c8<\/li>\n\n\n\n<li>C++23\u306e\u4e88\u5b9a\u3055\u308c\u308b\u6a5f\u80fd<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u3068\u30bb\u30ad\u30e5\u30ea\u30c6\u30a3<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u30e1\u30e2\u30ea\u30e2\u30c7\u30eb\u3068\u4e26\u884c\u51e6\u7406<\/li>\n\n\n\n<li>\u30bb\u30ad\u30e5\u30a2\u30b3\u30fc\u30c7\u30a3\u30f3\u30b0\u898f\u7d04<\/li>\n\n\n\n<li>\u30d7\u30ed\u30d5\u30a1\u30a4\u30ea\u30f3\u30b0\u3068\u30d9\u30f3\u30c1\u30de\u30fc\u30af<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u30c4\u30fc\u30eb\u3068\u30e9\u30a4\u30d6\u30e9\u30ea<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u9759\u7684\u89e3\u6790\u30c4\u30fc\u30eb<\/li>\n\n\n\n<li>\u30e6\u30cb\u30c3\u30c8\u30c6\u30b9\u30c8\u30d5\u30ec\u30fc\u30e0\u30ef\u30fc\u30af<\/li>\n\n\n\n<li>\u30d1\u30d5\u30a9\u30fc\u30de\u30f3\u30b9\u6e2c\u5b9a\u30c4\u30fc\u30eb<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u3053\u308c\u3089\u306e\u77e5\u8b58\u3092\u6df1\u3081\u308b\u3053\u3068\u3067\u3001\u3088\u308a\u5805\u7262\u3067\u52b9\u7387\u7684\u306a\u6587\u5b57\u5217\u51e6\u7406\u30b7\u30b9\u30c6\u30e0\u3092\u8a2d\u8a08\u30fb\u5b9f\u88c5\u3067\u304d\u308b\u3088\u3046\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":["post-2089","post","type-post","status-publish","format-standard","category-cpp","nothumb"],"_links":{"self":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/2089","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=2089"}],"version-history":[{"count":2,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/2089\/revisions"}],"predecessor-version":[{"id":2091,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=\/wp\/v2\/posts\/2089\/revisions\/2091"}],"wp:attachment":[{"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2089"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2089"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dexall.co.jp\/articles\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2089"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}