C\u548cC++\u4e2d\u6709\u5f88\u591a\u51fd\u6570\u7684\u53c2\u6570\u7c7b\u578b\u4f7f\u7528\u4e86const\u8fd9\u4e2a\u5173\u952e\u5b57\u3002\u4f8b\u5982C\u8bed\u8a00string.h\u5934\u6587\u4ef6\u4e2d\u7684strcpy\u5b57\u7b26\u4e32\u590d\u5236\u51fd\u6570\uff0c\u5b83\u7684\u539f\u578b\u662f<\/p>\n
\r\nchar * strcpy (char * Dest, const char * Source)\r\n<\/pre>\n\u5176\u4e2d\u7684const\u8868\u793astrcpy\u51fd\u6570\u4fdd\u8bc1\u4e0d\u4fee\u6539Source\u6307\u5411\u7684\u5185\u5b58\u4e2d\u7684\u6570\u636e\uff0c\u800c\u672a\u52a0const\u7684Dest\u6307\u5411\u7684\u5185\u5bb9\u5374\u53ef\u4ee5\u88ab\u4fee\u6539\u3002<\/p>\n
\u518d\u5982stdlib.h\u4e2d\u7684qsort\u5feb\u901f\u6392\u5e8f\u51fd\u6570\u539f\u578b\u5982\u4e0b\uff1a<\/p>\n
\r\nvoid qsort (void * Base, size_t NumOfElements, size_t SizeOfElements, int (*PtFuncCompare)(const void *, const void *))\r\n<\/pre>\n\u5176\u4e2d\u6700\u540e\u4e00\u4e2a\u53c2\u6570\u662f\u4e00\u4e2a\u51fd\u6570\u6307\u9488\uff0cqsort\u9700\u8981\u4f60\u63d0\u4f9b\u4e00\u4e2a\u6bd4\u8f83\u51fd\u6570\uff0c\u8fd9\u4e2a\u6bd4\u8f83\u51fd\u6570\u4ee5\u4e24\u4e2a\u6307\u9488\u4e3a\u53c2\u6570\uff0cconst\u8981\u6c42\u4f60\u4e0d\u80fd\u901a\u8fc7\u6307\u9488\u4fee\u6539\u5176\u6307\u5411\u7684\u6570\u636e\u3002<\/p>\n
\u7136\u800c\u6307\u9488\u7c7b\u578b\u7684\u53c2\u6570\u52a0\u4e86const\u7684\u51fd\u6570\u5c31\u771f\u7684\u80fd\u4fdd\u8bc1\u5b83\u4e0d\u4f1a\u4fee\u6539\u6570\u636e\u5417\uff1f<\/p>\n
<\/p>\n
\u6211\u4eec\u6d4b\u8bd5\u4e00\u4e0b\u76f4\u63a5\u4fee\u6539\u6307\u5411\u7684\u6570\u636e\u4f1a\u600e\u4e48\u6837\uff1a<\/p>\n
\r\n#include<stdio.h>\r\n\r\nvoid change_const(const char *s){\r\n *s='B';\r\n}\r\n\r\nint main(){\r\n char s[]="Hello";\r\n change_const(s);\r\n printf("%s",s);\r\n return 0;\r\n}\r\n<\/pre>\n\u7f16\u8bd1\u4e0d\u901a\u8fc7\uff01\u9519\u8bef\u5728\u7b2c\u56db\u884c\uff1a[Error] assignment of read-only location ‘* s’<\/p>\n
*s\u7684\u7c7b\u578b\u662fconst char\uff0c\u6240\u4ee5\u5bf9\u5b83\u8d4b\u503c\u5fc5\u7136\u7f16\u8bd1\u4e0d\u901a\u8fc7\u3002<\/p>\n
\u518d\u8bd5\u8bd5\u7528\u51fd\u6570\u4fee\u6539s\u6307\u5411\u7684\u6570\u636e\uff1a<\/p>\n
\r\n#include<stdio.h>\r\n#include<string.h>\r\n\r\nvoid change_const(const char *s){\r\n strcpy(s,"Hi");\r\n}\r\n\r\nint main(){\r\n char s[]="Hello";\r\n change_const(s);\r\n printf("%s",s);\r\n return 0;\r\n}\r\n<\/pre>\n\u8fd8\u662f\u7f16\u8bd1\u4e0d\u901a\u8fc7\uff01\u9519\u8bef\u5728\u7b2c\u4e94\u884c\uff1a[Error] invalid conversion from ‘const char*’ to ‘char*’<\/p>\n
strcpy\u7684\u7b2c\u4e00\u4e2a\u53c2\u6570\u7c7b\u578b\u662fchar *\uff0c\u4f46\u662f\u4f60\u8bd5\u56fe\u4f20\u5165\u4e00\u4e2aconst char *\u7c7b\u578b\u7684\u503c\uff0c\u7f16\u8bd1\u5668\u544a\u8bc9\u4f60\u4e0d\u80fd\u8fd9\u6837\u7c7b\u578b\u8f6c\u6362\u3002<\/p>\n
\u522b\u5fd8\u4e86C\/C++\u6709\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u3002\u5982\u679c\u7f16\u8bd1\u5668\u4e0d\u8ba9\u8f6c\u6362\uff0c\u6211\u53ef\u4ee5\u5f3a\u5236\u628aconst char *\u8f6c\u6362\u6210char *\u7c7b\u578b\uff01<\/p>\n
\r\n#include<stdio.h>\r\n#include<string.h>\r\n\r\nvoid change_const(const char *s){\r\n ((char*)s)[0]='B';\r\n}\r\n\r\nint main(){\r\n char s[]="Hello";\r\n change_const(s);\r\n printf("%s",s);\r\n return 0;\r\n}\r\n<\/pre>\n\u7f16\u8bd1\u901a\u8fc7\uff0c\u7a0b\u5e8f\u8f93\u51faBello\uff0c\u8bf4\u660econst\u6307\u9488\u6307\u5411\u7684\u6570\u636e\u88ab\u6210\u529f\u4fee\u6539\u4e86\u3002<\/p>\n
\u518d\u8bd5\u8bd5strcpy\uff1a<\/p>\n
\r\n#include<stdio.h>\r\n#include<string.h>\r\n\r\nvoid change_const(const char *s){\r\n strcpy((char*)s,"Hi");\r\n}\r\n\r\nint main(){\r\n char s[]="Hello";\r\n change_const(s);\r\n printf("%s",s);\r\n return 0;\r\n}\r\n<\/pre>\n\u7f16\u8bd1\u901a\u8fc7\uff0c\u7a0b\u5e8f\u8f93\u51faHi\u3002<\/p>\n
\u8fd9\u4e2a\u6d4b\u8bd5\u8bf4\u660eC\/C++\u7684const\u662f\u4e0d\u53ef\u4fe1\u7684\uff0c\u901a\u8fc7\u5f3a\u5236\u7c7b\u578b\u8f6c\u6362\u53ef\u4ee5\u8ba9const\u5931\u6548\u3002<\/p>\n
\u7136\u800c\u6211\u5e76\u4e0d\u63a8\u8350\u4ee5\u8fd9\u79cd\u65b9\u5f0f\u5199\u4ee3\u7801\uff0c\u8fd9\u6837\u7684\u4ee3\u7801\u662f\u4e0d\u89c4\u8303\u7684\u3002\u6211\u505a\u8fd9\u4e2a\u6d4b\u8bd5\u662f\u4e3a\u4e86\u8bf4\u660econst\u53ea\u662f\u7f16\u8bd1\u65f6\u7684\u9650\u5236\u7f62\u4e86\uff0c\u8fd0\u884c\u65f6\u5e76\u4e0d\u80fd\u4fdd\u8bc1\u52a0\u4e86const\u7684\u53d8\u91cf\u4e0d\u88ab\u4fee\u6539\u3002\u5982\u679c\u6709\u4e00\u4e2a\u7b2c\u4e09\u65b9\u63d0\u4f9b\u7684\u5e93\uff0c\u6211\u4eec\u4e0d\u80fd\u7edd\u5bf9\u4fe1\u4efb\u53c2\u6570\u4e2d\u52a0\u4e86const\u7684\u51fd\u6570\u4e0d\u4f1a\u4fee\u6539\u6211\u4eec\u7684\u6570\u636e\u3002<\/p>\n
\u6ce8\uff1aconst int * a \u548c int * const b \u662f\u4e0d\u540c\u7684\u3002\u524d\u8005\u8981\u6c42\u4e0d\u80fd\u901a\u8fc7a\u4fee\u6539\u6307\u5411\u7684\u5185\u5bb9\uff0c\u4f46\u662f\u6307\u9488a\u53ef\u4ee5\u88ab\u4fee\u6539\uff0c\u4f7f\u5b83\u6307\u5411\u522b\u7684\u5730\u65b9\uff1b\u540e\u8005\u672c\u8eab\u4e0d\u80fd\u88ab\u4fee\u6539\uff0c\u4f46\u662f\u53ef\u4ee5\u901a\u8fc7\u8fd9\u4e2a\u6307\u9488\u4fee\u6539\u5176\u6307\u5411\u7684\u5185\u5bb9\u3002*a=1\u65e0\u6cd5\u7f16\u8bd1\u901a\u8fc7\uff0c\u4f46\u662fa=&x\u53ef\u4ee5\uff1bb=&x\u4e0d\u80fd\u7f16\u8bd1\u901a\u8fc7\uff0c\u4f46\u662f*b=1\u53ef\u4ee5\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
C\u548cC++\u4e2d\u6709\u5f88\u591a\u51fd\u6570\u7684\u53c2\u6570\u7c7b\u578b\u4f7f\u7528\u4e86const\u8fd9\u4e2a\u5173\u952e\u5b57\u3002\u4f8b\u5982C\u8bed\u8a00string.h\u5934\u6587\u4ef6\u4e2d\u7684strcpy\u5b57 … \u7ee7\u7eed\u9605\u8bfb\u201cC\/C++\u4e2d\u7684const\u53ef\u4fe1\u5417\uff1f\u201d<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-188","post","type-post","status-publish","format-standard","hentry","category-c-language"],"_links":{"self":[{"href":"https:\/\/sqrt-1.me\/index.php?rest_route=\/wp\/v2\/posts\/188","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sqrt-1.me\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sqrt-1.me\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sqrt-1.me\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sqrt-1.me\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=188"}],"version-history":[{"count":6,"href":"https:\/\/sqrt-1.me\/index.php?rest_route=\/wp\/v2\/posts\/188\/revisions"}],"predecessor-version":[{"id":339,"href":"https:\/\/sqrt-1.me\/index.php?rest_route=\/wp\/v2\/posts\/188\/revisions\/339"}],"wp:attachment":[{"href":"https:\/\/sqrt-1.me\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=188"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sqrt-1.me\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=188"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sqrt-1.me\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=188"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}