{"id":18078,"date":"2023-02-22T17:18:46","date_gmt":"2023-02-22T09:18:46","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=18078"},"modified":"2023-07-30T22:57:45","modified_gmt":"2023-07-30T14:57:45","slug":"c-%e9%a3%8e%e6%a0%bc%e7%9a%84%e7%b1%bb%e5%9e%8b%e8%bd%ac%e6%8d%a2%e5%92%8c-dynamic_cast-%e6%9c%89%e4%bb%80%e4%b9%88%e5%8c%ba%e5%88%ab","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/18078.html","title":{"rendered":"C \u98ce\u683c\u7684\u7c7b\u578b\u8f6c\u6362\u548c dynamic_cast \u6709\u4ec0\u4e48\u533a\u522b"},"content":{"rendered":"<blockquote class=\"wp-block-quote\">\n<p>C \u98ce\u683c\u7684\u7c7b\u578b\u8f6c\u6362\u548c dynamic_cast \u7684\u533a\u522b\u662f\uff1a\u524d\u8005\u662fC\u8bed\u8a00\u7684\u7c7b\u578b\u8f6c\u6362\uff0c\u5f53\u7136C++\u4e3a\u4e86\u517c\u5bb9\u4e5f\u662f\u652f\u6301\u7684\u3002\u5b83\u76f8\u5f53\u4e8econst_cast \/ static_cast \/ reinterpret_cast\u6328\u4e2a\u8bd5\u4e00\u904d\uff1bdynamic_cast\u4f1a\u8bd5\u7740\u628a\u57fa\u7c7b\u7684\u6307\u9488\u6216\u5f15\u7528\u8f6c\u6362\u6210\u5b50\u7c7b\u7684\uff0c\u5e76\u4e14\u505a\u7c7b\u578b\u68c0\u67e5\u3002<\/p>\n<\/blockquote>\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img fetchpriority=\"high\" alt=\"\" class=\"wp-image-18079\" decoding=\"async\" height=\"421\" sizes=\"(max-width: 680px) 100vw, 680px\" src=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/02\/\u6dfb\u52a0\u6807\u9898-11-16.png?x-oss-process=image\/auto-orient,1\/format,webp\" srcset=\"https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/02\/\u6dfb\u52a0\u6807\u9898-11-16.png?x-oss-process=image\/auto-orient,1\/format,webp 680w, https:\/\/cdn-docs.pingcode.com\/wp-content\/uploads\/2023\/02\/\u6dfb\u52a0\u6807\u9898-11-16-300x186.png 300w\" width=\"680\"\/><\/figure>\n<\/div>\n<h2 class=\"wp-block-heading\"><strong>\u4e00\u3001C \u98ce\u683c\u7684\u7c7b\u578b\u8f6c\u6362\u548c dynamic_cast \u7684\u533a\u522b<\/strong><\/h2>\n<p>\u524d\u8005\u662fC\u8bed\u8a00\u7684\u7c7b\u578b\u8f6c\u6362\uff0c\u5f53\u7136C++\u4e3a\u4e86\u517c\u5bb9\u4e5f\u662f\u652f\u6301\u7684\u3002\u5b83\u76f8\u5f53\u4e8econst_cast \/ static_cast \/ reinterpret_cast\u6328\u4e2a\u8bd5\u4e00\u904d\uff0c\u54ea\u4e2a\u80fd\u7528\u5c31\u7528\u54ea\u4e2a\u3002C++\u91cc\u662f\u4e0d\u63d0\u5021\u7684\uff0c\u56e0\u4e3a\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u662f\u5bb9\u6613\u4f7f\u7528\u4e0d\u5f53\u5e26\u6765\u98ce\u9669\u7684\uff0c\u800cC\u7684\u7c7b\u578b\u8f6c\u6362\u592a\u5bb9\u6613\u5199\u4e86\uff0c\u53c8\u4e0d\u591f\u663e\u773c\u3002<\/p>\n<p>dynamic_cast\u4f1a\u8bd5\u7740\u628a\u57fa\u7c7b\u7684\u6307\u9488\u6216\u5f15\u7528\u8f6c\u6362\u6210\u5b50\u7c7b\u7684\uff0c\u5e76\u4e14\u505a\u7c7b\u578b\u68c0\u67e5\u3002\u5982\u679c\u7c7b\u578b\u5bf9\u4e86\uff0c\u624d\u8fd4\u56de\u8f6c\u6362\u7ed3\u679c\uff1b\u7c7b\u578b\u4e0d\u5bf9\uff0c\u8fd4\u56de\u7a7a\u6307\u9488\u3002<\/p>\n<p>dynamic_cast\u7528\u4e8e\u5c06\u4e00\u4e2a\u7236\u7c7b\u5bf9\u8c61\u7684\u6307\u9488\/\u5f15\u7528\u8f6c\u6362\u4e3a\u5b50\u7c7b\u5bf9\u8c61\u7684\u6307\u9488\u6216\u5f15\u7528\uff08\u52a8\u6001\u8f6c\u6362\uff09\u3002<\/p>\n<p>dynamic_cast&lt; type_id &gt;(expression)<\/p>\n<p>type_id \u5fc5\u987b\u662f\u7c7b\u7684\u6307\u9488\u3001\u7c7b\u7684\u5f15\u7528\u6216\u8005void*\u3002<\/p>\n<p>\u4e3b\u8981\u7528\u4e8e\u7c7b\u5c42\u6b21\u95f4\u7684\u4e0a\u884c\u8f6c\u6362\u548c\u4e0b\u884c\u8f6c\u6362\uff0c\u8fd8\u53ef\u4ee5\u7528\u4e8e\u7c7b\u4e4b\u95f4\u7684\u4ea4\u53c9\u8f6c\u6362\u3002<\/p>\n<p>dynamic_cast\u53ea\u80fd\u7528\u4e8e\u542b\u6709\u865a\u51fd\u6570\u7684\u7c7b\uff1b<\/p>\n<p>\u8fdb\u884c\u4e0a\u884c\u8f6c\u6362\u7684\u65f6\u5019\uff0c\u4e0estatic_cast \u7684\u4f5c\u7528\u4e00\u6837\u3002\u4e0b\u884c\u8f6c\u6362\u7684\u65f6\u5019\uff0c\u5177\u6709\u7c7b\u578b\u68c0\u67e5\u7684\u529f\u80fd\uff0c\u6bd4static_cast\u66f4\u5b89\u5168\u3002<\/p>\n<p>dynamic_cast\u4f1a\u5148\u68c0\u67e5\u662f\u5426\u80fd\u8f6c\u6362\u6210\u529f\uff0c\u5982\u679c\u80fd\u5219\u8f6c\u6362\uff0c\u4e0d\u80fd\u5219\u8fd4\u56de0\u3002<\/p>\n<p><strong>\u5ef6\u4f38\u9605\u8bfb\uff1a<\/strong><\/p>\n<h2 class=\"wp-block-heading\"><strong>\u4e8c\u3001C\u8bed\u8a00<\/strong><\/h2>\n<p>C\u8bed\u8a00\u662f\u4e00\u95e8\u9762\u5411\u8fc7\u7a0b\u7684\u3001\u62bd\u8c61\u5316\u7684\u901a\u7528\u7a0b\u5e8f\u8bbe\u8ba1\u8bed\u8a00\uff0c\u5e7f\u6cdb\u5e94\u7528\u4e8e\u5e95\u5c42\u5f00\u53d1\u3002C\u8bed\u8a00\u80fd\u4ee5\u7b80\u6613\u7684\u65b9\u5f0f\u7f16\u8bd1\u3001\u5904\u7406\u4f4e\u7ea7\u5b58\u50a8\u5668\u3002C\u8bed\u8a00\u662f\u4ec5\u4ea7\u751f\u5c11\u91cf\u7684\u673a\u5668\u8bed\u8a00\u4ee5\u53ca\u4e0d\u9700\u8981\u4efb\u4f55\u8fd0\u884c\u73af\u5883\u652f\u6301\u4fbf\u80fd\u8fd0\u884c\u7684\u9ad8\u6548\u7387\u7a0b\u5e8f\u8bbe\u8ba1\u8bed\u8a00\u3002\u5c3d\u7ba1C\u8bed\u8a00\u63d0\u4f9b\u4e86\u8bb8\u591a\u4f4e\u7ea7\u5904\u7406\u7684\u529f\u80fd\uff0c\u4f46\u4ecd\u7136\u4fdd\u6301\u7740\u8de8\u5e73\u53f0\u7684\u7279\u6027\uff0c\u4ee5\u4e00\u4e2a\u6807\u51c6\u89c4\u683c\u5199\u51fa\u7684C\u8bed\u8a00\u7a0b\u5e8f\u53ef\u5728\u5305\u62ec\u7c7b\u4f3c\u5d4c\u5165\u5f0f\u5904\u7406\u5668\u4ee5\u53ca\u8d85\u7ea7\u8ba1\u7b97\u673a\u7b49\u4f5c\u4e1a\u5e73\u53f0\u7684\u8bb8\u591a\u8ba1\u7b97\u673a\u5e73\u53f0\u4e0a\u8fdb\u884c\u7f16\u8bd1\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"C \u98ce\u683c\u7684\u7c7b\u578b\u8f6c\u6362\u548c dynamic_cast \u7684\u533a\u522b\u662f\uff1a\u524d\u8005\u662fC\u8bed\u8a00\u7684\u7c7b\u578b\u8f6c\u6362\uff0c\u5f53\u7136C++\u4e3a\u4e86\u517c\u5bb9\u4e5f\u662f\u652f\u6301\u7684 [&hellip;]","protected":false},"author":1,"featured_media":18079,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/18078"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=18078"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/18078\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/18079"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=18078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=18078"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=18078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}