{"id":292,"date":"2022-05-01T15:50:43","date_gmt":"2022-05-01T07:50:43","guid":{"rendered":"https:\/\/aaaahui.top\/?p=292"},"modified":"2022-08-13T21:25:09","modified_gmt":"2022-08-13T13:25:09","slug":"cpointer","status":"publish","type":"post","link":"https:\/\/ahui.blog\/index.php\/2022\/05\/01\/cpointer\/","title":{"rendered":"\u57fa\u7840\u5b66\u4e60\u8bb0\u5f55\u2014\u2014C\u8bed\u8a00\u6307\u9488"},"content":{"rendered":"

\u6307\u9488<\/h2>\n

\u6307\u9488\u4e5f\u5c31\u662f\u5185\u5b58\u5730\u5740\uff0c\u6307\u9488\u53d8\u91cf\u662f\u7528\u6765\u5b58\u653e\u5185\u5b58\u5730\u5740\u7684\u53d8\u91cf\uff0c\u6307\u9488\u53d8\u91cf\u5728\u5185\u5b58\u4e2d\u4e5f\u6709\u81ea\u5df1\u7684\u5730\u5740\uff0c\u53ea\u4e0d\u8fc7\u5b83\u7684\u5730\u5740\u4e2d\u5b58\u653e\u7684\u662f\u522b\u4eba\u7684\u5730\u5740\u3002<\/strong><\/p>\n

\u5728C\u8bed\u8a00\u4e2d\u662f\u53ef\u4ee5\u76f4\u63a5\u64cd\u4f5c\u5185\u5b58\u7684\uff0c\u6307\u9488\u7684\u610f\u4e49\u5c31\u662f\u6307\u5411\u67d0\u4e00\u4e2a\u5185\u5b58\u5730\u5740\uff0c\u6700\u7b80\u5355\u7684\u793a\u4f8b\u5982\u4e0b\uff1a\u6307\u9488\u53d8\u91cf<\/p>\n

#include <stdio.h>\n\nint main ()\n{\n    int var_runoob = 10;\n    int *p;              \/\/ \u5b9a\u4e49\u6307\u9488\u53d8\u91cf\n    p = &var_runoob;\n\n   printf("var_runoob \u53d8\u91cf\u7684\u5730\u5740\uff1a %p\\n", p);\n   return 0;\n}\n<\/code><\/pre>\n
\u8fd9\u91cc\u7684*p\u5c31\u662f\u5b9a\u4e49\u4e00\u4e2a\u6307\u9488\u53d8\u91cf\uff0c\u90a3\u4e48\u8fd9\u91cc\u7684p\u5c31\u53ef\u4ee5\u901a\u8fc7&\u7b26\u53f7\u53d6\u5176\u4ed6\u53d8\u91cf\u5185\u5b58\u4e2d\u7684\u5730\u5740\u540e\uff0c\u8d4b\u503c\u7ed9p\u8fd9\u4e2a\u6307\u9488\u53d8\u91cf\u4e86\u3002\u4e5f\u5c31\u662f\u8bf4\u6307\u9488\u53d8\u91cf\u5e76\u4e0d\u662f\u4e00\u4e2a\u5b9e\u9645\u5b58\u5728\u7684\u53d8\u91cf\uff0c\u53ea\u662f\u6307\u5411\u4e86\u5176\u4ed6\u53d8\u91cf\u5185\u5b58\u4e2d\u7684\u5730\u5740\u4ece\u800c\u83b7\u5f97\u5176\u4ed6\u53d8\u91cf\u7684\u503c\u3002<\/p>\n
    \n
  • p\u662f\u4e00\u4e2a\u6307\u9488\uff0c\u5b58\u50a8\u7740\u53d8\u91cfvar_runoob\u7684\u5730\u5740\u3002<\/li>\n
  • \u6307\u9488p\u7684\u7c7b\u578b\u5fc5\u987b\u4e0evar_runoob\u7684\u7c7b\u578b\u4e00\u81f4\uff0c\u56e0\u4e3a\u6574\u578b\u7684\u6307\u9488\u53ea\u80fd\u5b58\u50a8\u6574\u578b\u53d8\u91cf\u7684\u6307\u9488\u5730\u5740<\/li>\n<\/ul>\n
    NULL\u6307\u9488<\/h3>\n
    \u5728\u53d8\u91cf\u58f0\u660e\u7684\u65f6\u5019\uff0c\u5982\u679c\u6ca1\u6709\u786e\u5207\u7684\u5730\u5740\u53ef\u4ee5\u8d4b\u503c\uff0c\u53ef\u4ee5\u7ed9\u6307\u9488\u53d8\u91cf\u8d4b\u4e00\u4e2aNULL\u503c\uff0c\u6b64\u65f6\u8fd9\u4e2a\u6307\u9488\u88ab\u79f0\u4e3a\u7a7a\u6307\u9488\u3002<\/p>\n
    #include <stdio.h>\n\nint main ()\n{\n   int  *ptr = NULL;\n\n   printf("ptr \u7684\u5730\u5740\u662f %p\\n", ptr  );\n\n   return 0;\n}<\/code><\/pre>\n
    \u6307\u9488\u7684\u7b97\u672f\u8fd0\u7b97<\/h3>\n
    \u6307\u9488\u4e5f\u53ef\u4ee5\u8fdb\u884c++\u3001--\u3001+\u3001-\u8fd9\u56db\u79cd\u7b97\u6570\u8fd0\u7b97\uff0c\u8fd9\u91cc\u7684\u8fd0\u7b97\u4e5f\u5c31\u662f\u5bf9\u6307\u9488\u6307\u5411\u7684\u5730\u5740\u7684\u8fd0\u7b97\uff0c\u4f8b\u5982\u5c06*p\u8fdb\u884c++\u64cd\u4f5c\uff0c\u90a3\u4e48\u5c31\u662f\u6839\u636ep\u8fd9\u4e2a\u6307\u9488\u7684\u6307\u9488\u7c7b\u578b\uff0c\u5411\u540e\u79fb\u52a8\u4e00\u4e2a\u7c7b\u578b\u957f\u5ea6\u7684\u5730\u5740\uff0c\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n
    #include <stdio.h>\n\nint main ()\n{\n   int  *ptr = NULL;\n   int test = 1;\n   ptr = &test;\n   ptr++;\n\n   printf("ptr \u7684\u5730\u5740\u662f %p\\n", ptr);\n\n   return 0;\n}<\/code><\/pre>\n
    \u8fd9\u91ccptr\u6307\u9488\u7684\u7c7b\u578b\u4e3a\u6574\u578b\uff0c\u4e00\u4e2a\u6574\u578b\u6570\u5b57\u5728\u5185\u5b58\u4e2d\u5360\u56db\u4e2a\u5b57\u8282\uff0c\u90a3\u4e48ptr++\u5c31\u5c06ptr\u539f\u672c\u6307\u5411\u7684000000000061FE14\u7ed9\u53d8\u6210\u4e86\u6307\u5411000000000061FE18\u3002<\/p>\n
    \u5982\u679cptr-1\u7684\u8bdd\uff0c\u90a3\u4e48\u6b64\u65f6\u7684\u5730\u5740\u5c31\u5e94\u8be5\u4e3aptr\u51cf\u53bb\u4e00\u4e2a\u6574\u578b\u7684\u5b57\u8282\u4e4b\u540e\u7684\u5730\u5740\uff0c\u4e5f\u5c31\u662f\u6307\u5411\u7684\u5185\u5b58\u4f4d\u7f6e\u5411\u524d\u79fb\u52a8\u56db\u4e2a\u5b57\u8282\u3002<\/p>\n
    \u6307\u9488\u7684\u6bd4\u8f83<\/h3>\n
    \u6307\u9488\u53ef\u4ee5\u7528\u5173\u7cfb\u8fd0\u7b97\u7b26\u8fdb\u884c\u6bd4\u8f83\uff0c\u4f8b\u5982==\u3001<\u3001>\u3002\u5982\u679c p1 \u548c p2 \u6307\u5411\u4e24\u4e2a\u76f8\u5173\u7684\u53d8\u91cf\uff0c\u6bd4\u5982\u540c\u4e00\u4e2a\u6570\u7ec4\u4e2d\u7684\u4e0d\u540c\u5143\u7d20\uff0c\u5219\u53ef\u5bf9 p1 \u548c p2 \u8fdb\u884c\u5927\u5c0f\u6bd4\u8f83\u3002<\/p>\n
    \u6307\u9488\u6570\u7ec4<\/h3>\n
    \u5728C\u8bed\u8a00\u4e2d\uff0c\u6307\u9488\u7c7b\u578b\u53ef\u4ee5\u4e3a\u6570\u7ec4\u7c7b\u578b\uff0c\u4e0e\u6307\u9488\u53d8\u91cf\u7c7b\u4f3c\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n
    #include <stdio.h>\n\nconst int MAX = 3;\n\nint main ()\n{\n   int  var[] = {10, 100, 200};\n   int i, *ptr[MAX];\n\n   for ( i = 0; i < MAX; i++)\n   {\n      ptr[i] = &var[i]; \/* \u8d4b\u503c\u4e3a\u6574\u6570\u7684\u5730\u5740 *\/\n   }\n   for ( i = 0; i < MAX; i++)\n   {\n      printf("Value of var[%d] = %d\\n", i, *ptr[i] );\n   }\n   return 0;\n}<\/code><\/pre>\n
    \u4e0a\u9762\u7684\u4ee3\u7801\u9996\u5148\u5b9a\u4e49\u4e86ptr\u6307\u9488\u4e3aint\u7c7b\u578b\u7684\u6570\u7ec4\uff0c\u7136\u540e\u518d\u5faa\u73af\u53d6var[]\u6570\u7ec4\u4e2d\u7684\u503c\u7684\u5730\u5740\u8d4b\u7ed9ptr\u6307\u9488\u6570\u7ec4\u7684\u952e\uff0c\u4e5f\u5c31\u662f\u8bf4\u518d\u6307\u9488\u6570\u7ec4\u4e2d\uff0c\u6bcf\u4e00\u4e2a\u952e\u90fd\u662f\u4e00\u4e2a\u6307\u9488\uff0c\u53ef\u4ee5\u6307\u5411\u4e00\u4e2aint\u7c7b\u578b\u7684\u5185\u5b58\u5730\u5740\u3002<\/p>\n
    \u6307\u5411\u6307\u9488\u7684\u6307\u9488<\/h3>\n
    \u6307\u5411\u6307\u9488\u7684\u6307\u9488\u662f\u4e00\u79cd\u591a\u7ea7\u95f4\u63a5\u5bfb\u5740\u7684\u5f62\u5f0f\uff0c\u6216\u8005\u8bf4\u662f\u4e00\u4e2a\u6307\u9488\u94fe\u3002\u901a\u5e38\uff0c\u4e00\u4e2a\u6307\u9488\u5305\u542b\u4e00\u4e2a\u53d8\u91cf\u7684\u5730\u5740\u3002\u5f53\u6211\u4eec\u5b9a\u4e49\u4e00\u4e2a\u6307\u5411\u6307\u9488\u7684\u6307\u9488\u65f6\uff0c\u7b2c\u4e00\u4e2a\u6307\u9488\u5305\u542b\u4e86\u7b2c\u4e8c\u4e2a\u6307\u9488\u7684\u5730\u5740\uff0c\u7b2c\u4e8c\u4e2a\u6307\u9488\u6307\u5411\u5305\u542b\u5b9e\u9645\u503c\u7684\u4f4d\u7f6e\u3002<\/p>\n
    \u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n
    #include <stdio.h>\n\nint main ()\n{\n   int  V;\n   int  *Pt1;\n   int  **Pt2;\n\n   V = 100;\n\n   \/* \u83b7\u53d6 V \u7684\u5730\u5740 *\/\n   Pt1 = &V;\n\n   \/* \u4f7f\u7528\u8fd0\u7b97\u7b26 & \u83b7\u53d6 Pt1 \u7684\u5730\u5740 *\/\n   Pt2 = &Pt1;\n\n   \/* \u4f7f\u7528 pptr \u83b7\u53d6\u503c *\/\n   printf("var = %d\\n", V );\n   printf("Pt1 = %p\\n", Pt1 );\n   printf("*Pt1 = %d\\n", *Pt1 );\n    printf("Pt2 = %p\\n", Pt2 );\n   printf("**Pt2 = %d\\n", **Pt2);\n\n   return 0;\n}<\/code><\/pre>\n
    \u5728\u4ee5\u4e0a\u4ee3\u7801\u4e2d\uff0c\u5b9a\u4e49\u4e86Pt1\u6574\u578b\u6307\u9488\u53d8\u91cf\uff0c\u800cPt2\u662f\u4e00\u4e2a\u6574\u578b\u7684\u6307\u5411\u6307\u9488\u7684\u6307\u9488\u53d8\u91cf\u3002<\/p>\n
    \u4f20\u9012\u6307\u9488\u7ed9\u51fd\u6570<\/h3>\n
    C\u8bed\u8a00\u4e2d\u5141\u8bb8\u4f20\u9012\u6307\u9488\u7ed9\u51fd\u6570\uff0c\u53ea\u9700\u8981\u58f0\u660e\u51fd\u6570\u53c2\u6570\u4e3a\u6307\u9488\u7c7b\u578b\u5373\u53ef\u3002\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
    #include <stdio.h>\n#include <time.h>\n\nvoid getSeconds(unsigned long *par);\n\nint main ()\n{\n   unsigned long sec;\n\n   getSeconds( &sec );\n\n   \/* \u8f93\u51fa\u5b9e\u9645\u503c *\/\n   printf("Number of seconds: %ld\\n", sec );\n\n   return 0;\n}\n\nvoid getSeconds(unsigned long *par)\n{\n   \/* \u83b7\u53d6\u5f53\u524d\u7684\u79d2\u6570 *\/\n   *par = time( NULL );\n   return;\n}<\/code><\/pre>\n
    \u4e5f\u5c31\u662f\u8bf4\u76f4\u63a5\u5c06\u6307\u9488\u4f20\u9012\u7ed9\u51fd\u6570\uff0c\u90a3\u4e48\u51fd\u6570\u63a5\u6536\u4e4b\u540e\u5bf9\u53c2\u6570\u7684\u64cd\u4f5c\u4e5f\u5c31\u662f\u76f4\u63a5\u5bf9\u5185\u5b58\u4e2d\u76f8\u5e94\u5730\u5740\u7684\u5185\u5bb9\u7684\u64cd\u4f5c\u3002<\/p>\n
    \u4ece\u51fd\u6570\u8fd4\u56de\u6307\u9488<\/h3>\n
    C\u8bed\u8a00\u4e2d\u7684\u51fd\u6570\u8fd4\u56de\u503c\u53ef\u4ee5\u662f\u4e00\u4e2a\u6307\u9488\uff0c\u4f8b\u5982\u5982\u4e0b\u51fd\u6570\uff1a<\/p>\n
    int * getRandom( )\n{\n   static int  r[10];\n   int i;\n\n   \/* \u8bbe\u7f6e\u79cd\u5b50 *\/\n   srand( (unsigned)time( NULL ) );\n   for ( i = 0; i < 10; ++i)\n   {\n      r[i] = rand();\n      printf("%d\\n", r[i] );\n   }\n\n   return r;\n}<\/code><\/pre>\n
    \u5728\u51fd\u6570\u5b9a\u4e49\u4e2d\uff0c\u5728\u51fd\u6570\u540d\u524d\u9762\u52a0\u4e0a*\u5c31\u53ef\u4ee5\u6307\u5b9a\u8be5\u51fd\u6570\u8fd4\u56de\u7684\u7ed3\u679c\u4e3a\u6307\u9488\u3002<\/p>\n
    \u76f8\u5e94\u7684\uff0c\u5982\u679c\u51fd\u6570\u8fd4\u56de\u503c\u4e3a\u6307\u9488\uff0c\u5219\u9700\u8981\u7528\u4e00\u4e2a\u6307\u9488\u53d8\u91cf\u53bb\u63a5\u53d7\u8fd4\u56de\u7684\u7ed3\u679c\uff0c\u4f8b\u5982\uff1a<\/p>\n
    #include <stdio.h>\n#include <time.h>\n#include <stdlib.h> \n\n\/* \u8981\u751f\u6210\u548c\u8fd4\u56de\u968f\u673a\u6570\u7684\u51fd\u6570 *\/\nint * getRandom( )\n{\n   static int  r[10];\n   int i;\n\n   \/* \u8bbe\u7f6e\u79cd\u5b50 *\/\n   srand( (unsigned)time( NULL ) );\n   for ( i = 0; i < 10; ++i)\n   {\n      r[i] = rand();\n      printf("%d\\n", r[i] );\n   }\n\n   return r;\n}\n\n\/* \u8981\u8c03\u7528\u4e0a\u9762\u5b9a\u4e49\u51fd\u6570\u7684\u4e3b\u51fd\u6570 *\/\nint main ()\n{\n   \/* \u4e00\u4e2a\u6307\u5411\u6574\u6570\u7684\u6307\u9488 *\/\n   int *p;\n   int i;\n\n   p = getRandom();\n   for ( i = 0; i < 10; i++ )\n   {\n       printf("*(p + [%d]) : %d\\n", i, *(p + i) );\n   }\n\n   return 0;\n}\n<\/code><\/pre>\n
    \u4e0a\u9762\u7684p\u5c31\u662f\u4e00\u4e2aint\u7c7b\u578b\u7684\u6307\u9488\u53d8\u91cf\uff0c\u90a3\u4e48getRandom\u8fd4\u56de\u7684\u6307\u9488\u5c31\u53ef\u4ee5\u88abp\u63a5\u6536\uff0c\u5e76\u4e14p\u63a5\u6536\u5230\u7684\u662f\u51fd\u6570\u8fd4\u56de\u5185\u5bb9\u7684\u5185\u5b58\u5730\u5740\u5757\u4e2d\u6700\u524d\u9762\u7684\u5730\u5740\uff0c\u4e5f\u5c31\u662fr\u6570\u7ec4\u7684\u7b2c\u4e00\u4e2a\u7ec4\u503c\u7684\u5185\u5b58\u5730\u5740\u3002<\/p>\n
    \u5982\u679c\u60f3\u8981\u53d6\u6570\u7ec4\u4e2d\u7684\u6240\u6709\u5730\u5740\uff0c\u90a3\u4e48\u53ef\u4ee5\u4f7f\u7528\u4e0a\u8ff0\u4ee3\u7801\u4e2d\u7684\u8fd9\u4e00\u5757\uff1a<\/p>\n
    for ( i = 0; i < 10; i++ )\n   {\n       printf("*(p + [%d]) : %d\\n", i, *(p + i) );\n   }<\/code><\/pre>\n
    \u53ea\u9700\u8981\u904d\u5386\u6570\u7ec4\u4e2d\u7684\u503c\uff0c\u7136\u540e\u5c06\u503c\u4e0ep\u6307\u9488\u76f8\u52a0\u5373\u53ef\u83b7\u5f97r\u6570\u7ec4\u76f8\u5e94\u7684\u7ec4\u503c\u3002<\/p>\n
    \u51fd\u6570\u6307\u9488<\/h2>\n
    \u51fd\u6570\u6307\u9488\u662f\u5c06\u6307\u9488\u6307\u5411\u4e00\u4e2a\u51fd\u6570\uff0c\u8c03\u7528\u7684\u65f6\u5019\u4e5f\u53ef\u4ee5\u76f4\u63a5\u901a\u8fc7\u51fd\u6570\u6307\u9488\u8c03\u7528\u51fd\u6570\u3002\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n
    #include <stdio.h>\n\nint max(int x, int y)\n{\n    return x > y ? x : y;\n}\n\nint main(void)\n{\n    \/* p \u662f\u51fd\u6570\u6307\u9488 *\/\n    int (* p)(int, int) = & max; \/\/ &\u53ef\u4ee5\u7701\u7565\n    int a, b, c, d;\n\n    printf("\u8bf7\u8f93\u5165\u4e09\u4e2a\u6570\u5b57:");\n    scanf("%d %d %d", & a, & b, & c);\n\n    \/* \u4e0e\u76f4\u63a5\u8c03\u7528\u51fd\u6570\u7b49\u4ef7\uff0cd = max(max(a, b), c) *\/\n    d = p(p(a, b), c); \n\n    printf("\u6700\u5927\u7684\u6570\u5b57\u662f: %d\\n", d);\n\n    return 0;\n}<\/code><\/pre>\n
    \u4e0a\u8ff0\u4ee3\u7801\u5b9a\u4e49*p\u6307\u9488\u53d8\u91cf\u65f6\uff0c\u540e\u9762\u5e26\u4e0a\u4e86(int,int)\uff0c\u4e5f\u5c31\u662f\u53c2\u6570\u7c7b\u578b\uff0c\u8d4b\u503c\u4e3a& max\uff0c\u4e5f\u5c31\u662f\u53d6max\u51fd\u6570\u7684\u5730\u5740\uff0c\u90a3\u4e48\u8fd9\u4e2a\u6307\u9488\u53d8\u91cfp\u73b0\u5728\u5c31\u6307\u5411\u4e86max\u51fd\u6570\u5728\u5185\u5b58\u4e2d\u7684\u5730\u5740\u3002<\/p>\n
    \u6b64\u65f6\u8c03\u7528max\u51fd\u6570\u5c31\u53ef\u4ee5\u901a\u8fc7p\u8fd9\u4e2a\u6307\u9488\u53d8\u91cf\u53bb\u8c03\u7528\uff0c\u76f4\u63a5\u4f7f\u7528p(a,b)\u5373\u53ef\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
    \u6307\u9488 \u6307\u9488\u4e5f\u5c31\u662f\u5185\u5b58\u5730\u5740\uff0c\u6307\u9488\u53d8\u91cf\u662f\u7528\u6765\u5b58\u653e\u5185\u5b58\u5730\u5740\u7684\u53d8\u91cf\uff0c\u6307\u9488\u53d8\u91cf\u5728\u5185\u5b58\u4e2d\u4e5f\u6709\u81ea\u5df1\u7684\u5730\u5740\uff0c\u53ea\u4e0d\u8fc7\u5b83\u7684\u5730\u5740\u4e2d\u5b58 … \u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25],"tags":[26],"class_list":["post-292","post","type-post","status-publish","format-standard","hentry","category-basic_knowledge","tag-c"],"_links":{"self":[{"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/posts\/292","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/comments?post=292"}],"version-history":[{"count":2,"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/posts\/292\/revisions"}],"predecessor-version":[{"id":295,"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/posts\/292\/revisions\/295"}],"wp:attachment":[{"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/media?parent=292"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/categories?post=292"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ahui.blog\/index.php\/wp-json\/wp\/v2\/tags?post=292"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}