{"id":26072,"date":"2023-04-24T12:01:34","date_gmt":"2023-04-24T04:01:34","guid":{"rendered":"https:\/\/docs.pingcode.com\/?p=26072"},"modified":"2023-07-30T23:29:25","modified_gmt":"2023-07-30T15:29:25","slug":"%e4%b8%ba%e4%bb%80%e4%b9%88c%e4%b8%ad%e5%90%91map%e6%b7%bb%e5%8a%a0%e5%af%b9%e8%b1%a1%e6%97%b6%e4%b8%8d%e8%83%bd%e4%bd%bf%e7%94%a8%e6%8b%b7%e8%b4%9d%e6%9e%84%e9%80%a0%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/26072.html","title":{"rendered":"\u4e3a\u4ec0\u4e48c++\u4e2d\u5411map\u6dfb\u52a0\u5bf9\u8c61\u65f6\u4e0d\u80fd\u4f7f\u7528\u62f7\u8d1d\u6784\u9020\u51fd\u6570"},"content":{"rendered":"
\n

\u56e0\u4e3a\u5c31\u7b97\u4f60\u7c7b\u91cc\u9762\u4e0d\u663e\u5f0f\u5199\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u90a3\u4e48\u5728\u7c7b\u5185\u6ca1\u6709\u5176\u4ed6\u6784\u9020\u51fd\u6570\u7684\u65f6\u5019\uff0c\u7f16\u8bd1\u5668\u4e5f\u662f\u4f1a\u9690\u5f0f\u5730\u751f\u6210\u4e00\u4e2a\u9ed8\u8ba4\u7684\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u7684\u3002\u53c8\u4e0d\u662f\u7528 C++11 \u91cc Person(const Person&) = delete \u7684\u8bed\u6cd5\u660e\u786e\u7981\u6b62\u62f7\u8d1d\u6784\u9020\u3002<\/p>\n<\/blockquote>\n

\n
\"\"<\/figure>\n<\/div>\n

\u4e00\u3001\u4e3a\u4ec0\u4e48c++\u4e2d\u5411map\u6dfb\u52a0\u5bf9\u8c61\u65f6\u4e0d\u80fd\u4f7f\u7528\u62f7\u8d1d\u6784\u9020\u51fd\u6570<\/strong><\/h2>\n

\u5c31\u7b97\u4f60\u7c7b\u91cc\u9762\u4e0d\u663e\u5f0f\u5199\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u90a3\u4e48\u5728\u7c7b\u5185\u6ca1\u6709\u5176\u4ed6\u6784\u9020\u51fd\u6570\u7684\u65f6\u5019\uff0c\u7f16\u8bd1\u5668\u4e5f\u662f\u4f1a\u9690\u5f0f\u5730\u751f\u6210\u4e00\u4e2a\u9ed8\u8ba4\u7684\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u7684\u3002\u53c8\u4e0d\u662f\u7528 C++11 \u91cc Person(const Person&) = delete \u7684\u8bed\u6cd5\u660e\u786e\u7981\u6b62\u62f7\u8d1d\u6784\u9020\u3002\u6240\u4ee5\u5149\u5220\u6389\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u7684\u4ee3\u7801\u6839\u672c\u5c31\u4e0d\u8db3\u4ee5\u8bf4\u660e\u4f60\u7684 Person \u4e0d\u80fd\u62f7\u8d1d\u6784\u9020\u3002\u4f60\u7684\u731c\u6d4b\u6839\u672c\u5c31\u4e0d\u6210\u7acb\u3002<\/p>\n

\u6839\u636e\u521d\u5b66\u8005\u5199 C++ \u65f6\u7684\u4e00\u8d2f\u574f\u4e60\u60ef\uff0c\u6211\u731c\u53ef\u80fd\u662f\u4f60\u62f7\u8d1d\u6784\u9020\u6ca1\u52a0\u5e38\u5f15\u7528\u3002\u679c\u7136\uff0c\u6211\u628a\u4e0a\u9762\u4ee3\u7801\u91cc\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u6539\u6210 Person(Person&) \uff0c\u5c31\u51fa\u73b0\u4e86\u8ddf\u4f60\u4e00\u6837\u7684\u7f16\u8bd1\u9519\u8bef\u3002<\/p>\n

\u4e3a\u4ec0\u4e48\u7981\u7528\u62f7\u8d1d\u6784\u9020\u51fd\u6570<\/strong><\/h3>\n

\u5173\u4e8e\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u7684\u7981\u7528\u539f\u56e0\uff0c\u6211\u76ee\u524d\u4e86\u89e3\u7684\u4e3b\u8981\u662f\u4e24\u4e2a\u539f\u56e0\u3002\u540d\u5217\u524d\u8305\u662f\u6d45\u62f7\u8d1d\u95ee\u9898\uff0c\u7b2c\u4e8c \u4e2a\u5219\u662f\u57fa\u7c7b\u62f7\u8d1d\u95ee\u9898\u3002<\/p>\n

<\/a>\u6d45\u62f7\u8d1d\u95ee\u9898<\/strong><\/h4>\n

\u7f16\u8bd1\u5668\u9ed8\u8ba4\u751f\u6210\u7684\u6784\u9020\u51fd\u6570\uff0c\u662fmemberwise\u62f7\u8d1d^1<\/a>\uff0c\u4e5f\u5c31\u662f\u9010\u4e2a\u62f7\u8d1d\u6210\u5458\u53d8\u91cf\uff0c\u5bf9\u4e8e \u4e0b\u9762\u8fd9\u4e2a\u7c7b\u7684\u5b9a\u4e49^2\uff1a<\/p>\n

\n\n\n\n
\u00a0<\/td>\nclass Widget { public: Widget(const std::string &name) : name_(name), buf_(new char[10]) {} ~Widget() { delete buf_; } \u00a0 private: std::string name_; char *buf_; };<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

\u9ed8\u8ba4\u751f\u6210\u7684\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u4f1a\u76f4\u63a5\u62f7\u8d1dbuf_\u7684\u503c\uff0c\u5bfc\u81f4\u4e24\u4e2aWidget\u5bf9\u8c61\u6307\u5411\u540c\u4e00\u4e2a\u7f13 \u51b2\u533a\uff0c\u8fd9\u4f1a\u5bfc\u81f4\u6790\u6784\u7684\u65f6\u5019\u4e24\u6b21\u5220\u9664\u540c\u4e00\u7247\u533a\u57df\u7684\u95ee\u9898\uff08\u8fd9\u4e2a\u95ee\u9898\u53c8\u53eb\u53cc\u6740\u95ee\u9898\uff09\u3002<\/p>\n

\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u7684\u65b9\u5f0f\u6709\u5f88\u591a\uff1a<\/p>\n

    \n
  1. \u81ea\u5df1\u7f16\u5199\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u7136\u540e\u5728\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u4e2d\u521b\u5efa\u65b0\u7684buf_\uff0c\u4e0d\u8fc7\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u7684 \u7f16\u5199\u9700\u8981\u8003\u8651\u5f02\u5e38\u5b89\u5168\u7684\u95ee\u9898\uff0c\u6240\u4ee5\u7f16\u5199\u8d77\u6765\u6709\u4e00\u5b9a\u7684\u96be\u5ea6\u3002<\/li>\n
  2. \u4f7f\u7528\u00a0shared_ptr\u00a0\u8fd9\u6837\u7684\u667a\u80fd\u6307\u9488\uff0c\u8ba9\u6240\u6709\u7684\u00a0Widget\u00a0\u5bf9\u8c61\u5171\u4eab\u4e00\u7247\u00a0buf_\uff0c\u5e76 \u8ba9\u00a0shared_ptr\u00a0\u7684\u5f15\u7528\u8ba1\u6570\u673a\u5236\u5e2e\u4f60\u667a\u80fd\u7684\u5904\u7406\u5220\u9664\u95ee\u9898\u3002<\/li>\n
  3. \u7981\u7528\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u548c\u8d4b\u503c\u64cd\u4f5c\u7b26\u3002\u5982\u679c\u4f60\u6839\u672c\u6ca1\u6709\u6253\u7b97\u8ba9Widget\u652f\u6301\u62f7\u8d1d\uff0c\u4f60\u5b8c\u5168\u53ef \u4ee5\u76f4\u63a5\u7981\u7528\u8fd9\u4e24\u64cd\u4f5c\uff0c\u8fd9\u6837\u4e00\u6765\uff0c\u524d\u9762\u63d0\u5230\u7684\u8fd9\u4e9b\u95ee\u9898\u5c31\u90fd\u4e0d\u662f\u95ee\u9898\u4e86\u3002<\/li>\n<\/ol>\n

    <\/a>\u57fa\u7c7b\u62f7\u8d1d\u6784\u9020\u95ee\u9898<\/strong><\/h4>\n

    \u5982\u679c\u6211\u4eec\u4e0d\u53bb\u81ea\u5df1\u7f16\u5199\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u7f16\u8bd1\u5668\u9ed8\u8ba4\u751f\u6210\u7684\u7248\u672c\u4f1a\u81ea\u52a8\u8c03\u7528\u57fa\u7c7b\u7684\u62f7\u8d1d\u6784\u9020 \u51fd\u6570\u5b8c\u6210\u57fa\u7c7b\u7684\u62f7\u8d1d\uff1a<\/p>\n

    \n\n\n\n
    \u00a0<\/td>\nclass Base { public: Base() { cout << \u201cBase Default Constructor\u201d << endl; } Base(const Base &) { cout << \u201cBase Copy Constructor\u201d << endl; } }; \u00a0 class Drived : public Base { public: Drived() { cout << \u201cDrived Default Constructor\u201d << endl; } }; \u00a0 int main(void) { Drived d1; Drived d2(d1); }<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

    \u4e0a\u9762\u8fd9\u6bb5\u4ee3\u7801\u7684\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n

    \n\n\n\n
    \u00a0<\/td>\nBase Default Constructor Drived Default Constructor \u00a0 Base Copy Constructor \/\/ \u81ea\u52a8\u8c03\u7528\u4e86\u57fa\u7c7b\u7684\u62f7\u8d1d\u6784\u9020\u51fd\u6570<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

    \u4f46\u662f\u5982\u679c\u6211\u4eec\u51fa\u4e8e\u67d0\u79cd\u539f\u56e0\u7f16\u5199\u4e86\uff0c\u81ea\u5df1\u7f16\u5199\u4e86\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff08\u6bd4\u5982\u56e0\u4e3a\u4e0a\u6587\u4e2d\u63d0\u5230\u7684\u6d45 \u62f7\u8d1d\u95ee\u9898\uff09\uff0c\u7f16\u8bd1\u5668\u4e0d\u4f1a\u5e2e\u6211\u4eec\u5b89\u63d2\u57fa\u7c7b\u7684\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u5b83\u53ea\u4f1a\u5728\u5fc5\u8981\u7684\u65f6\u5019\u5e2e\u6211\u4eec\u5b89 \u63d2\u57fa\u7c7b\u7684\u9ed8\u8ba4\u6784\u9020\u51fd\u6570\uff1a<\/p>\n

    \n\n\n\n
    \u00a0<\/td>\nclass Base { public: Base() { cout << \u201cBase Default Constructor\u201d << endl; } Base(const Base &) { cout << \u201cBase Copy Constructor\u201d << endl; } }; \u00a0 class Drived : public Base { public: Drived() { cout << \u201cDrived Default Constructor\u201d << endl; } Drived(const Drived& d) { cout << \u201cDrived Copy Constructor\u201d << endl; } }; \u00a0 int main(void) { Drived d1; Drived d2(d1); }<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

    \u4e0a\u9762\u8fd9\u6bb5\u4ee3\u7801\u7684\u8f93\u51fa\u5982\u4e0b\uff1a<\/p>\n

    \n\n\n\n
    1 2 3 4 5<\/td>\nBase Default Constructor Drived Default Constructor \u00a0 Base Default Constructor \/\/ \u8c03\u7528\u4e86\u57fa\u7c7b\u7684\u9ed8\u8ba4\u6784\u9020\u51fd\u6570 Drived Copy Constructor<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

    \u8fd9\u5f53\u7136\u4e0d\u662f\u6211\u4eec\u60f3\u8981\u770b\u5230\u7684\u7ed3\u679c\uff0c\u4e3a\u4e86\u80fd\u591f\u5f97\u5230\u6b63\u786e\u7684\u7ed3\u679c\uff0c\u6211\u4eec\u9700\u8981\u81ea\u5df1\u624b\u52a8\u8c03\u7528\u57fa\u7c7b \u7684\u5bf9\u5e94\u7248\u672c\u62f7\u8d1d\u57fa\u7c7b\u5bf9\u8c61\u3002<\/p>\n

    \n\n\n\n
    \u00a0<\/td>\nDrived(const Drived& d) : Base(d) { cout << \u201cDrived Copy Constructor\u201d << endl; }<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

    \u8fd9\u672c\u6765\u4e0d\u662f\u4ec0\u4e48\u95ee\u9898\uff0c\u53ea\u4e0d\u8fc7\u6709\u4e9b\u4eba\u7f16\u5199\u62f7\u8d1d\u6784\u9020\u51fd\u6570\u7684\u65f6\u5019\u4f1a\u5fd8\u8bb0\u8fd9\u4e00\u70b9\uff0c\u6240\u4ee5\u5bfc\u81f4\u57fa \u7c7b\u5b50\u5bf9\u8c61\u6ca1\u6709\u6b63\u5e38\u590d\u5236\uff0c\u9020\u6210\u5f88\u96be\u5bdf\u89c9\u7684BUG\u3002\u6240\u4ee5\u4e3a\u4e86\u4e00\u52b3\u6c38\u9038\u7684\u89e3\u51b3\u8fd9\u4e9b\u86cb\u75bc\u7684\u95ee\u9898\uff0c \u5e72\u8106\u5c31\u76f4\u63a5\u7981\u7528\u62f7\u8d1d\u6784\u9020\u548c\u8d4b\u503c\u64cd\u4f5c\u7b26\u3002<\/p>\n

    \u5ef6\u4f38\u9605\u8bfb\uff1a
    <\/strong><\/p>\n

    \u4e8c\u3001\u6784\u9020\u51fd\u6570\u662f\u4ec0\u4e48<\/strong><\/h2>\n

    \u6784\u9020\u51fd\u6570\uff08Constructor\uff09\u5c31\u662f\u7528\u6765\u6784\u9020\u5bf9\u8c61\u7684\u51fd\u6570\u3002C++\u5bf9\u8c61\u5728\u521b\u5efa\u7684\u8fc7\u7a0b\u4e2d\u4f1a\u8c03\u7528\u6784\u9020\u51fd\u6570\u5bf9\u7c7b\u4e2d\u6210\u5458\u8fdb\u884c\u521d\u59cb\u5316\u3002<\/p>\n

    \u6784\u9020\u51fd\u6570\u5305\u542b\u6709\u666e\u901a\u6784\u9020\u51fd\u6570\u3001\u62f7\u8d1d\u6784\u9020\uff08Copy Constructor\uff09\u51fd\u6570\u4ee5\u53caC++11\u4ee5\u540e\u65b0\u589e\u7684\u79fb\u52a8\u6784\u9020\uff08Move Constructor\uff09\u51fd\u6570\u4e09\u79cd\u3002\u901a\u5e38\uff0c\u6211\u4eec\u8bf4\u6784\u9020\u51fd\u6570\u53ea\u7279\u6307\u666e\u901a\u6784\u9020\u51fd\u6570\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u56e0\u4e3a\u5c31\u7b97\u4f60\u7c7b\u91cc\u9762\u4e0d\u663e\u5f0f\u5199\u62f7\u8d1d\u6784\u9020\u51fd\u6570\uff0c\u90a3\u4e48\u5728\u7c7b\u5185\u6ca1\u6709\u5176\u4ed6\u6784\u9020\u51fd\u6570\u7684\u65f6\u5019\uff0c\u7f16\u8bd1\u5668\u4e5f\u662f\u4f1a\u9690\u5f0f\u5730\u751f\u6210\u4e00\u4e2a\u9ed8\u8ba4\u7684\u62f7\u8d1d\u6784 […]","protected":false},"author":1,"featured_media":26073,"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\/26072"}],"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=26072"}],"version-history":[{"count":0,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/26072\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/26073"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=26072"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=26072"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=26072"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}