C++ const \u5141\u8bb8\u6307\u5b9a\u4e00\u4e2a\u8bed\u4e49\u7ea6\u675f\uff0c\u7f16\u8bd1\u5668\u4f1a\u5f3a\u5236\u5b9e\u65bd\u8fd9\u4e2a\u7ea6\u675f\uff0c\u5141\u8bb8\u7a0b\u5e8f\u5458\u544a\u8bc9\u7f16\u8bd1\u5668\u67d0\u503c\u662f\u4fdd\u6301\u4e0d\u53d8\u7684\u3002\u5982\u679c\u5728\u7f16\u7a0b\u4e2d\u786e\u5b9e\u6709\u67d0\u4e2a\u503c\u4fdd\u6301\u4e0d\u53d8\uff0c\u5c31\u5e94\u8be5\u660e\u786e\u4f7f\u7528const\uff0c\u8fd9\u6837\u53ef\u4ee5\u83b7\u5f97\u7f16\u8bd1\u5668\u7684\u5e2e\u52a9\u3002<\/p>\n

\u4e00\u3001const\u4fee\u9970\u666e\u901a\u7c7b\u578b\u7684\u53d8\u91cf<\/strong><\/div>\n
const int a = 7; \r\nint b = a; \/\/ \u6b63\u786e\r\na = 8; \/\/ \u9519\u8bef\uff0c\u4e0d\u80fd\u6539\u53d8<\/pre>\n
a \u88ab\u5b9a\u4e49\u4e3a\u4e00\u4e2a\u5e38\u91cf\uff0c\u5e76\u4e14\u53ef\u4ee5\u5c06 a \u8d4b\u503c\u7ed9 b\uff0c\u4f46\u662f\u4e0d\u80fd\u7ed9 a \u518d\u6b21\u8d4b\u503c\u3002\u5bf9\u4e00\u4e2a\u5e38\u91cf\u8d4b\u503c\u662f\u8fdd\u6cd5\u7684\u4e8b\u60c5\uff0c\u56e0\u4e3a a \u88ab\u7f16\u8bd1\u5668\u8ba4\u4e3a\u662f\u4e00\u4e2a\u5e38\u91cf\uff0c\u5176\u503c\u4e0d\u5141\u8bb8\u4fee\u6539\u3002<\/p>\n
\u63a5\u7740\u770b\u5982\u4e0b\u7684\u64cd\u4f5c\uff1a<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nint main(void)\r\n{\r\n const int a = 7;\r\n int *p = (int*)&a;\r\n *p = 8;\r\n cout<<\/pre>\n
\u5bf9\u4e8e const \u53d8\u91cf a\uff0c\u6211\u4eec\u53d6\u53d8\u91cf\u7684\u5730\u5740\u5e76\u8f6c\u6362\u8d4b\u503c\u7ed9 \u6307\u5411 int \u7684\u6307\u9488\uff0c\u7136\u540e\u5229\u7528 *p = 8; \u91cd\u65b0\u5bf9\u53d8\u91cf a \u5730\u5740\u5185\u7684\u503c\u8d4b\u503c\uff0c\u7136\u540e\u8f93\u51fa\u67e5\u770b a \u7684\u503c\u3002<\/p>\n
\u4ece\u4e0b\u9762\u7684\u8c03\u8bd5\u7a97\u53e3\u770b\u5230 a \u7684\u503c\u88ab\u6539\u53d8\u4e3a 8\uff0c\u4f46\u662f\u8f93\u51fa\u7684\u7ed3\u679c\u4ecd\u7136\u662f 7\u3002
\n $\"\"$
\n $\"\"$
\n\u4ece\u7ed3\u679c\u4e2d\u6211\u4eec\u53ef\u4ee5\u770b\u5230\uff0c\u7f16\u8bd1\u5668\u7136\u540e\u8ba4\u4e3a a \u7684\u503c\u4e3a\u4e00\u5f00\u59cb\u5b9a\u4e49\u7684 7\uff0c\u6240\u4ee5\u5bf9 const a \u7684\u64cd\u4f5c\u5c31\u4f1a\u4ea7\u751f\u4e0a\u9762\u7684\u60c5\u51b5\u3002\u6240\u4ee5\u5343\u4e07\u4e0d\u8981\u8f7b\u6613\u5bf9 const \u53d8\u91cf\u8bbe\u6cd5\u8d4b\u503c\uff0c\u8fd9\u4f1a\u4ea7\u751f\u610f\u60f3\u4e0d\u5230\u7684\u884c\u4e3a\u3002<\/p>\n
\u5982\u679c\u4e0d\u60f3\u8ba9\u7f16\u8bd1\u5668\u5bdf\u89c9\u5230\u4e0a\u9762\u5230\u5bf9 const \u7684\u64cd\u4f5c\uff0c\u6211\u4eec\u53ef\u4ee5\u5728 const \u524d\u9762\u52a0\u4e0a volatile \u5173\u952e\u5b57\u3002<\/p>\n
Volatile \u5173\u952e\u5b57\u8ddf const \u5bf9\u5e94\u76f8\u53cd\uff0c\u662f\u6613\u53d8\u7684\uff0c\u5bb9\u6613\u6539\u53d8\u7684\u610f\u601d\u3002\u6240\u4ee5\u4e0d\u4f1a\u88ab\u7f16\u8bd1\u5668\u4f18\u5316\uff0c\u7f16\u8bd1\u5668\u4e5f\u5c31\u4e0d\u4f1a\u6539\u53d8\u5bf9 a \u53d8\u91cf\u7684\u64cd\u4f5c\u3002<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nint main(void)\r\n{\r\n volatile const int a = 7;\r\n int *p = (int*)&a;\r\n *p = 8;\r\n cout<<\/pre>\n
\u8f93\u51fa\u7ed3\u679c\u5982\u6211\u4eec\u671f\u671b\u7684\u662f 8\u3002
\n $\"\"$ <\/p>\n
\u4e8c\u3001const \u4fee\u9970\u6307\u9488\u53d8\u91cf<\/strong><\/div>\n
const \u4fee\u9970\u6307\u9488\u53d8\u91cf\u6709\u4ee5\u4e0b\u4e09\u79cd\u60c5\u51b5\u3002<\/p>\n
\nA: const \u4fee\u9970\u6307\u9488\u6307\u5411\u7684\u5185\u5bb9\uff0c\u5219\u5185\u5bb9\u4e3a\u4e0d\u53ef\u53d8\u91cf\u3002
\nB: const \u4fee\u9970\u6307\u9488\uff0c\u5219\u6307\u9488\u4e3a\u4e0d\u53ef\u53d8\u91cf\u3002
\nC: const \u4fee\u9970\u6307\u9488\u548c\u6307\u9488\u6307\u5411\u7684\u5185\u5bb9\uff0c\u5219\u6307\u9488\u548c\u6307\u9488\u6307\u5411\u7684\u5185\u5bb9\u90fd\u4e3a\u4e0d\u53ef\u53d8\u91cf\u3002<\/ol>\n
\u5bf9\u4e8e A:<\/p>\n
const int *p = 8;<\/pre>\n
\u5219\u6307\u9488\u6307\u5411\u7684\u5185\u5bb9 8 \u4e0d\u53ef\u6539\u53d8\u3002\u7b80\u79f0\u5de6\u5b9a\u503c\uff0c\u56e0\u4e3a const \u4f4d\u4e8e * \u53f7\u7684\u5de6\u8fb9\u3002<\/p>\n
\u5bf9\u4e8e B:<\/p>\n
int a = 8;\r\nint* const p = &a;\r\n*p = 9; \/\/ \u6b63\u786e\r\nint b = 7;\r\np = &b; \/\/ \u9519\u8bef<\/pre>\n
\u5bf9\u4e8e const \u6307\u9488 p \u5176\u6307\u5411\u7684\u5185\u5b58\u5730\u5740\u4e0d\u80fd\u591f\u88ab\u6539\u53d8\uff0c\u4f46\u5176\u5185\u5bb9\u53ef\u4ee5\u6539\u53d8\u3002\u7b80\u79f0\uff0c\u53f3\u5b9a\u5411\u3002\u56e0\u4e3a const \u4f4d\u4e8e * \u53f7\u7684\u53f3\u8fb9\u3002<\/p>\n
\u5bf9\u4e8e C: \u5219\u662f A \u548c B\u7684\u5408\u5e76<\/p>\n
int a = 8;\r\nconst int * const p = &a;<\/pre>\n
\u8fd9\u65f6\uff0cconst p \u7684\u6307\u5411\u7684\u5185\u5bb9\u548c\u6307\u5411\u7684\u5185\u5b58\u5730\u5740\u90fd\u5df2\u56fa\u5b9a\uff0c\u4e0d\u53ef\u6539\u53d8\u3002<\/p>\n
\u5bf9\u4e8e A\uff0cB\uff0cC \u4e09\u79cd\u60c5\u51b5\uff0c\u6839\u636e const \u4f4d\u4e8e * \u53f7\u7684\u4f4d\u7f6e\u4e0d\u540c\uff0c\u6211\u603b\u7ed3\u4e09\u53e5\u8bdd\u4fbf\u4e8e\u8bb0\u5fc6\u7684\u8bdd\uff1a\"\u5de6\u5b9a\u503c\uff0c\u53f3\u5b9a\u5411\uff0cconst\u4fee\u9970\u4e0d\u53d8\u91cf\"\u3002<\/p>\n
\u4e09\u3001const\u53c2\u6570\u4f20\u9012\u548c\u51fd\u6570\u8fd4\u56de\u503c<\/strong><\/div>\n
\u5bf9\u4e8e const \u4fee\u9970\u51fd\u6570\u53c2\u6570\u53ef\u4ee5\u5206\u4e3a\u4e09\u79cd\u60c5\u51b5\u3002<\/p>\n
A\uff1a\u503c\u4f20\u9012\u7684 const \u4fee\u9970\u4f20\u9012\uff0c\u4e00\u822c\u8fd9\u79cd\u60c5\u51b5\u4e0d\u9700\u8981 const \u4fee\u9970\uff0c\u56e0\u4e3a\u51fd\u6570\u4f1a\u81ea\u52a8\u4ea7\u751f\u4e34\u65f6\u53d8\u91cf\u590d\u5236\u5b9e\u53c2\u503c\u3002<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nvoid Cpf(const int a)\r\n{\r\n cout<<\/pre>\n
B\uff1a\u5f53 const \u53c2\u6570\u4e3a\u6307\u9488\u65f6\uff0c\u53ef\u4ee5\u9632\u6b62\u6307\u9488\u88ab\u610f\u5916\u7be1\u6539\u3002<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nvoid Cpf(int *const a)\r\n{\r\n cout<<*a<<\" \";\r\n *a = 9;\r\n}\r\n \r\nint main(void)\r\n{\r\n int a = 8;\r\n Cpf(&a);\r\n cout<<\/pre>\n
C\uff1a\u81ea\u5b9a\u4e49\u7c7b\u578b\u7684\u53c2\u6570\u4f20\u9012\uff0c\u9700\u8981\u4e34\u65f6\u5bf9\u8c61\u590d\u5236\u53c2\u6570\uff0c\u5bf9\u4e8e\u4e34\u65f6\u5bf9\u8c61\u7684\u6784\u9020\uff0c\u9700\u8981\u8c03\u7528\u6784\u9020\u51fd\u6570\uff0c\u6bd4\u8f83\u6d6a\u8d39\u65f6\u95f4\uff0c\u56e0\u6b64\u6211\u4eec\u91c7\u53d6 const \u5916\u52a0\u5f15\u7528\u4f20\u9012\u7684\u65b9\u6cd5\u3002<\/p>\n
\u5e76\u4e14\u5bf9\u4e8e\u4e00\u822c\u7684 int\u3001double \u7b49\u5185\u7f6e\u7c7b\u578b\uff0c\u6211\u4eec\u4e0d\u91c7\u7528\u5f15\u7528\u7684\u4f20\u9012\u65b9\u5f0f\u3002<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nclass Test\r\n{\r\npublic:\r\n Test(){}\r\n Test(int _m):_cm(_m){}\r\n int get_cm()const\r\n {\r\n return _cm;\r\n }\r\n \r\nprivate:\r\n int _cm;\r\n};\r\n \r\n \r\n \r\nvoid Cmf(const Test& _tt)\r\n{\r\n cout<<_tt.get_cm();\r\n}\r\n \r\nint main(void)\r\n{\r\n Test t(8);\r\n Cmf(t);\r\n system(\"pause\");\r\n return 0;\r\n}<\/iostream><\/pre>\n
\u7ed3\u679c\u8f93\u51fa 8\u3002<\/p>\n
\u5bf9\u4e8e const \u4fee\u9970\u51fd\u6570\u7684\u8fd4\u56de\u503c\u3002<\/p>\n
Const \u4fee\u9970\u8fd4\u56de\u503c\u5206\u4e09\u79cd\u60c5\u51b5\u3002<\/p>\n
A\uff1aconst \u4fee\u9970\u5185\u7f6e\u7c7b\u578b\u7684\u8fd4\u56de\u503c\uff0c\u4fee\u9970\u4e0e\u4e0d\u4fee\u9970\u8fd4\u56de\u503c\u4f5c\u7528\u4e00\u6837\u3002<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nconst int Cmf()\r\n{\r\n return 1;\r\n}\r\n \r\nint Cpf()\r\n{\r\n return 0;\r\n}\r\n \r\nint main(void)\r\n{\r\n int _m = Cmf();\r\n int _n = Cpf();\r\n \r\n cout<<_m<<\" \"<<_n;\r\n system(\"pause\");\r\n return 0;\r\n}<\/iostream><\/pre>\n
B: const \u4fee\u9970\u81ea\u5b9a\u4e49\u7c7b\u578b\u7684\u4f5c\u4e3a\u8fd4\u56de\u503c\uff0c\u6b64\u65f6\u8fd4\u56de\u7684\u503c\u4e0d\u80fd\u4f5c\u4e3a\u5de6\u503c\u4f7f\u7528\uff0c\u65e2\u4e0d\u80fd\u88ab\u8d4b\u503c\uff0c\u4e5f\u4e0d\u80fd\u88ab\u4fee\u6539\u3002<\/p>\n
C: const \u4fee\u9970\u8fd4\u56de\u7684\u6307\u9488\u6216\u8005\u5f15\u7528\uff0c\u662f\u5426\u8fd4\u56de\u4e00\u4e2a\u6307\u5411 const \u7684\u6307\u9488\uff0c\u53d6\u51b3\u4e8e\u6211\u4eec\u60f3\u8ba9\u7528\u6237\u5e72\u4ec0\u4e48\u3002<\/p>\n
\u56db\u3001const\u4fee\u9970\u7c7b\u6210\u5458\u51fd\u6570<\/strong><\/div>\n
const \u4fee\u9970\u7c7b\u6210\u5458\u51fd\u6570\uff0c\u5176\u76ee\u7684\u662f\u9632\u6b62\u6210\u5458\u51fd\u6570\u4fee\u6539\u88ab\u8c03\u7528\u5bf9\u8c61\u7684\u503c\uff0c\u5982\u679c\u6211\u4eec\u4e0d\u60f3\u4fee\u6539\u4e00\u4e2a\u8c03\u7528\u5bf9\u8c61\u7684\u503c\uff0c\u6240\u6709\u7684\u6210\u5458\u51fd\u6570\u90fd\u5e94\u5f53\u58f0\u660e\u4e3a const \u6210\u5458\u51fd\u6570\u3002<\/p>\n
\u6ce8\u610f\uff1aconst \u5173\u952e\u5b57\u4e0d\u80fd\u4e0e static \u5173\u952e\u5b57\u540c\u65f6\u4f7f\u7528\uff0c\u56e0\u4e3a static \u5173\u952e\u5b57\u4fee\u9970\u9759\u6001\u6210\u5458\u51fd\u6570\uff0c\u9759\u6001\u6210\u5458\u51fd\u6570\u4e0d\u542b\u6709 this \u6307\u9488\uff0c\u5373\u4e0d\u80fd\u5b9e\u4f8b\u5316\uff0cconst \u6210\u5458\u51fd\u6570\u5fc5\u987b\u5177\u4f53\u5230\u67d0\u4e00\u5b9e\u4f8b\u3002<\/p>\n
\u4e0b\u9762\u7684 get_cm()const; \u51fd\u6570\u7528\u5230\u4e86 const \u6210\u5458\u51fd\u6570\uff1a<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\n \r\nusing namespace std;\r\n \r\nclass Test\r\n{\r\npublic:\r\n Test(){}\r\n Test(int _m):_cm(_m){}\r\n int get_cm()const\r\n {\r\n return _cm;\r\n }\r\n \r\nprivate:\r\n int _cm;\r\n};\r\n \r\n \r\n \r\nvoid Cmf(const Test& _tt)\r\n{\r\n cout<<_tt.get_cm();\r\n}\r\n \r\nint main(void)\r\n{\r\n Test t(8);\r\n Cmf(t);\r\n system(\"pause\");\r\n return 0;\r\n}<\/iostream><\/pre>\n
\u5982\u679c get_cm() \u53bb\u6389 const \u4fee\u9970\uff0c\u5219 Cmf \u4f20\u9012\u7684 const _tt \u5373\u4f7f\u6ca1\u6709\u6539\u53d8\u5bf9\u8c61\u7684\u503c\uff0c\u7f16\u8bd1\u5668\u4e5f\u8ba4\u4e3a\u51fd\u6570\u4f1a\u6539\u53d8\u5bf9\u8c61\u7684\u503c\uff0c\u6240\u4ee5\u6211\u4eec\u5c3d\u91cf\u6309\u7167\u8981\u6c42\u5c06\u6240\u6709\u7684\u4e0d\u9700\u8981\u6539\u53d8\u5bf9\u8c61\u5185\u5bb9\u7684\u51fd\u6570\u90fd\u4f5c\u4e3a const \u6210\u5458\u51fd\u6570\u3002<\/p>\n
\u5982\u679c\u6709\u4e2a\u6210\u5458\u51fd\u6570\u60f3\u4fee\u6539\u5bf9\u8c61\u4e2d\u7684\u67d0\u4e00\u4e2a\u6210\u5458\u600e\u4e48\u529e\uff1f\u8fd9\u65f6\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528 mutable \u5173\u952e\u5b57\u4fee\u9970\u8fd9\u4e2a\u6210\u5458\uff0cmutable \u7684\u610f\u601d\u4e5f\u662f\u6613\u53d8\u7684\uff0c\u5bb9\u6613\u6539\u53d8\u7684\u610f\u601d\uff0c\u88ab mutable \u5173\u952e\u5b57\u4fee\u9970\u7684\u6210\u5458\u53ef\u4ee5\u5904\u4e8e\u4e0d\u65ad\u53d8\u5316\u4e2d\uff0c\u5982\u4e0b\u9762\u7684\u4f8b\u5b50\u3002<\/p>\n
\u5b9e\u4f8b<\/strong><\/p>\n
#include\r\nusing namespace std;\r\nclass Test\r\n{\r\npublic:\r\n Test(int _m,int _t):_cm(_m),_ct(_t){}\r\n void Kf()const\r\n {\r\n ++_cm; \/\/ \u9519\u8bef\r\n ++_ct; \/\/ \u6b63\u786e\r\n }\r\nprivate:\r\n int _cm;\r\n mutable int _ct;\r\n};\r\n \r\nint main(void)\r\n{\r\n Test t(8,7);\r\n return 0;\r\n}<\/iostream><\/pre>\n
\u8fd9\u91cc\u6211\u4eec\u5728 Kf()const \u4e2d\u901a\u8fc7 ++_ct; \u4fee\u6539 _ct \u7684\u503c\uff0c\u4f46\u662f\u901a\u8fc7 ++_cm \u4fee\u6539 _cm \u5219\u4f1a\u62a5\u9519\u3002\u56e0\u4e3a ++_cm \u6ca1\u6709\u7528 mutable \u4fee\u9970\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
C++ const \u5141\u8bb8\u6307\u5b9a\u4e00\u4e2a\u8bed\u4e49\u7ea6\u675f\uff0c\u7f16\u8bd1\u5668\u4f1a\u5f3a\u5236\u5b9e\u65bd\u8fd9\u4e2a\u7ea6\u675f\uff0c\u5141\u8bb8\u7a0b\u5e8f\u5458\u544a\u8bc9\u7f16\u8bd1\u5668\u67d0\u503c\u662f\u4fdd\u6301\u4e0d\u53d8\u7684\u3002\u5982\u679c […]<\/p>\n","protected":false},"author":1470,"featured_media":199529,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[55],"tags":[],"class_list":["post-199525","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-thread"],"acf":[],"_links":{"self":[{"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/posts\/199525","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/users\/1470"}],"replies":[{"embeddable":true,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/comments?post=199525"}],"version-history":[{"count":4,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/posts\/199525\/revisions"}],"predecessor-version":[{"id":199542,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/posts\/199525\/revisions\/199542"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/media\/199529"}],"wp:attachment":[{"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/media?parent=199525"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/categories?post=199525"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gulass.cn\/wp-json\/wp\/v2\/tags?post=199525"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}