{"id":1718,"date":"2013-02-08T14:39:26","date_gmt":"2013-02-08T05:39:26","guid":{"rendered":"http:\/\/www.techscore.com\/blog\/?p=1718"},"modified":"2018-11-14T16:33:56","modified_gmt":"2018-11-14T07:33:56","slug":"how-to-calculate-array-length-in-c-and-cpp","status":"publish","type":"post","link":"https:\/\/www.techscore.com\/blog\/2013\/02\/08\/how-to-calculate-array-length-in-c-and-cpp\/","title":{"rendered":"C++\u3067\u9759\u7684\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u95a2\u6570"},"content":{"rendered":"<p>\u3053\u3093\u306b\u3061\u306f\u3001\u9234\u6728\u3067\u3059\u3002<\/p>\n<p>\u5510\u7a81\u3067\u3059\u304c\u3001C\/C++ \u3067\u9759\u7684\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b\u3068\u304d\u306b\u3001\u3069\u306e\u3088\u3046\u306a\u30b3\u30fc\u30c9\u3092\u66f8\u304d\u307e\u3059\u304b\uff1f<\/p>\n<p>&nbsp;<\/p>\n<h2>\u9759\u7684\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b<\/h2>\n<p>\u4ee5\u4e0b\u306e\u3088\u3046\u306b\u30b3\u30f3\u30d1\u30a4\u30eb\u6642\u70b9\u3067\u8981\u7d20\u6570\u304c\u6c7a\u5b9a\u3057\u3066\u3044\u308b\u914d\u5217\u306e\u3053\u3068\u3092\u9759\u7684\u914d\u5217\u3068\u8a00\u3044\u307e\u3059\u304c\u3001\u3053\u306e array \u304b\u3089\u8981\u7d20\u6570\u3067\u3042\u308b 10 \u3092\u3069\u306e\u3088\u3046\u306b\u6c42\u3081\u307e\u3059\u304b\uff1f<\/p>\n<pre class=\"lang:c decode:true\">int array[10];<\/pre>\n<p>\u77e5\u3063\u3066\u3044\u308b\u4eba\u306b\u3068\u3063\u3066\u306f\u975e\u5e38\u306b\u7c21\u5358\u3067\u3059\u306d\u3002<\/p>\n<p>\u6b21\u306e\u3088\u3046\u306b\u914d\u5217\u306e\u30b5\u30a4\u30ba (sizeof(array)) \u3092\u914d\u5217\u8981\u7d20\u306e\u30b5\u30a4\u30ba (sizeof(array[0])) \u3067\u5272\u308b\u3053\u3068\u3067\u3001\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b\u3053\u3068\u304c\u3067\u304d\u307e\u3059\u3002<\/p>\n<pre class=\"lang:c decode:true\">sizeof(array) \/ sizeof(array[0])<\/pre>\n<p>\u4e00\u822c\u7684\u306b\u306f\u4ee5\u4e0b\u306e ARRAY_LENGTH \u306e\u3088\u3046\u306a\u30de\u30af\u30ed\u3092\u5b9a\u7fa9\u3059\u308b\u3053\u3068\u304c\u591a\u3044\u304b\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n<pre class=\"lang:c decode:true\">#define ARRAY_LENGTH(array) (sizeof(array) \/ sizeof(array[0]))<\/pre>\n<p>&nbsp;<\/p>\n<h2>C++\u3067\u9759\u7684\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b<\/h2>\n<p>\u305d\u308c\u3067\u306f C \u8a00\u8a9e\u3067\u306f\u306a\u304f C++ \u3067\u9759\u7684\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b\u5834\u5408\u306f\u3001\u3069\u306e\u3088\u3046\u306a\u30b3\u30fc\u30c9\u3092\u66f8\u304d\u307e\u3059\u304b\uff1f<\/p>\n<p>C\u8a00\u8a9e\u3068\u540c\u3058\u65b9\u6cd5\u3067\u3082\u5b9f\u73fe\u3067\u304d\u307e\u3059\u304c\u3001C++ \u3067\u3042\u308c\u3070\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u3092\u7528\u3044\u305f\u5225\u306e\u89e3\u6cd5\u304c\u3042\u308a\u307e\u3059\u3002<\/p>\n<pre class=\"lang:c++ decode:true\">template\r\n&lt;\r\n    typename TYPE,\r\n    std::size_t SIZE\r\n&gt;\r\nstd::size_t array_length(const TYPE (&amp;array)[SIZE])\r\n{\r\n    return SIZE;\r\n}<\/pre>\n<p>\u6163\u308c\u3066\u3044\u306a\u3044\u3068\u5206\u304b\u308a\u3065\u3089\u3044\u304b\u3082\u3057\u308c\u307e\u305b\u3093\u304c\u3001\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u30d1\u30e9\u30e1\u30fc\u30bf\u306e TYPE \u306f\u914d\u5217\u8981\u7d20\u306e\u578b\u3001SIZE \u306f\u914d\u5217\u306e\u8981\u7d20\u6570\u3067\u3059\u3002<\/p>\n<p>\u7d30\u304b\u304f\u898b\u3066\u3044\u304f\u3068\u3001\u95a2\u6570 array_length \u3092\u5b9a\u7fa9\u3057\u3066\u304a\u308a\u3001\u623b\u308a\u5024\u306f\u914d\u5217\u306e\u8981\u7d20\u6570\u306a\u306e\u3067 std::size_t \u578b\u3067\u3059\u3002<\/p>\n<p>array_length \u306e\u5f15\u6570 array \u306f\u3001\u300c\u8981\u7d20\u6570\u304c SIZE \u3067\u3042\u308b TYPE \u578b\u914d\u5217\u306e const \u53c2\u7167\u300d\u3067\u3059\u3002<\/p>\n<ul>\n<li>(&amp;array) ... array \u306f\u53c2\u7167\u3067\u3042\u308b\u3002<\/li>\n<li>(&amp;array)[SIZE] ... array \u306f\u8981\u7d20\u6570 SIZE \u3067\u3042\u308b\u914d\u5217\u306e\u53c2\u7167\u3067\u3042\u308b\u3002<\/li>\n<li>TYPE (&amp;array)[SIZE] ... array \u306f\u8981\u7d20\u6570 SIZE \u3067\u3042\u308b TYPE \u578b\u914d\u5217\u306e\u53c2\u7167\u3067\u3042\u308b\u3002<\/li>\n<li>const TYPE (&amp;array)[SIZE] ... array \u306f\u8981\u7d20\u6570 SIZE \u3067\u3042\u308b TYPE \u578b\u914d\u5217\u306e const \u53c2\u7167\u3067\u3042\u308b\u3002<\/li>\n<\/ul>\n<p>\u3068\u3044\u3046\u5177\u5408\u306b\u6bb5\u968e\u7684\u306b\u898b\u3066\u3044\u3051\u3070\u7406\u89e3\u3057\u3084\u3059\u3044\u3068\u601d\u3044\u307e\u3059\u3002<\/p>\n<p>\u3055\u3066\u3001\u3082\u3046\u4e00\u5ea6\u30b3\u30fc\u30c9\u3092\u898b\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n<pre class=\"lang:c++ decode:true\">template\r\n&lt;\r\n    typename TYPE,\r\n    std::size_t SIZE\r\n&gt;\r\nstd::size_t array_length(const TYPE (&amp;array)[SIZE])\r\n{\r\n    return SIZE;\r\n}<\/pre>\n<p>\u5f15\u6570\u306e array \u306f\u95a2\u6570\u5185\u3067\u4f7f\u7528\u3055\u308c\u3066\u3044\u307e\u305b\u3093\u3002<\/p>\n<p>\u3053\u306e\u30b3\u30fc\u30c9\u3092\u30b3\u30f3\u30d1\u30a4\u30eb\u3059\u308b\u3068\u300c\u5f15\u6570 array \u306f\u4f7f\u7528\u3055\u308c\u3066\u3044\u307e\u305b\u3093\u30fb\u30fb\u30fb\u300d\u306e\u3088\u3046\u306a\u8b66\u544a\u30e1\u30c3\u30bb\u30fc\u30b8\u304c\u8868\u793a\u3055\u308c\u308b\u53ef\u80fd\u6027\u304c\u3042\u308a\u307e\u3059\uff08\u30b3\u30f3\u30d1\u30a4\u30e9\u306e\u8b66\u544a\u30ec\u30d9\u30eb\u304c\u4e00\u5b9a\u4ee5\u4e0a\u3060\u3068\u8868\u793a\u3055\u308c\u308b\u306f\u305a\u3067\u3059\uff09\u3002<\/p>\n<p>\u3068\u3044\u3046\u3053\u3068\u3067\u3001\u5f15\u6570\u306e\u5909\u6570\u540d array \u3092\u524a\u9664\u3057\u307e\u3059\u3002<\/p>\n<pre class=\"lang:c++ decode:true\">template\r\n&lt;\r\n    typename TYPE,\r\n    std::size_t SIZE\r\n&gt;\r\nstd::size_t array_length(const TYPE (&amp;)[SIZE])\r\n{\r\n    return SIZE;\r\n}<\/pre>\n<p>\u3053\u308c\u304c C++ \u3067\u9759\u7684\u914d\u5217\u306e\u8981\u7d20\u6570\u3092\u6c42\u3081\u308b\u30c6\u30f3\u30d7\u30ec\u30fc\u30c8\u95a2\u6570\u306e\u5b8c\u6210\u5f62\u3067\u3059\u3002<\/p>\n<p>\u8a66\u3057\u306b\u4f7f\u7528\u3057\u3066\u307f\u307e\u3057\u3087\u3046\u3002<\/p>\n<pre class=\"lang:c++ decode:true\">#include &lt;iostream&gt;\r\n\r\ntemplate\r\n&lt;\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0 typename TYPE,\r\n\u00a0\u00a0\u00a0 std::size_t SIZE\r\n&gt;\r\nstd::size_t array_length(const TYPE (&amp;)[SIZE])\r\n{\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0 return SIZE;\r\n}\r\n\r\nint main()\r\n{\u00a0 \u00a0\r\n\u00a0\u00a0\u00a0 int array1[10];\r\n\u00a0\u00a0\u00a0 int array2[20];\r\n\u00a0\u00a0\u00a0 int array3[30];\r\n\r\n\u00a0\u00a0\u00a0 std::cout &lt;&lt; array_length(array1) &lt;&lt; std::endl;\r\n\u00a0\u00a0\u00a0 std::cout &lt;&lt; array_length(array2) &lt;&lt; std::endl;\r\n\u00a0\u00a0\u00a0 std::cout &lt;&lt; array_length(array3) &lt;&lt; std::endl;\r\n}<\/pre>\n<p>\u5b9f\u884c\u3059\u308b\u3068\u3001<\/p>\n<pre class=\"lang:default decode:true\">10\r\n20\r\n30<\/pre>\n<p>\u3068\u8868\u793a\u3055\u308c\u307e\u3059\u3002<\/p>\n<p>C++ \u30aa\u30f3\u30ea\u30fc\u3067\u958b\u767a\u3059\u308b\u5834\u5408\u306f\u304a\u8a66\u3057\u304f\u3060\u3055\u3044\u3002<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u3053\u3093\u306b\u3061\u306f\u3001\u9234\u6728\u3067\u3059\u3002<br \/><a href=\"https:\/\/www.techscore.com\/blog\/2013\/02\/08\/how-to-calculate-array-length-in-c-and-cpp\/\">\u7d9a\u304d\u3092\u8aad\u3080...<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[81,79],"_links":{"self":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/1718"}],"collection":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/comments?post=1718"}],"version-history":[{"count":1,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/1718\/revisions"}],"predecessor-version":[{"id":17959,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/posts\/1718\/revisions\/17959"}],"wp:attachment":[{"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/media?parent=1718"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/categories?post=1718"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.techscore.com\/blog\/wp-json\/wp\/v2\/tags?post=1718"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}