{"id":343,"date":"2020-11-02T22:28:33","date_gmt":"2020-11-03T02:28:33","guid":{"rendered":"http:\/\/www.prglab.com\/blog\/?page_id=343"},"modified":"2020-11-02T22:28:33","modified_gmt":"2020-11-03T02:28:33","slug":"pointers","status":"publish","type":"page","link":"https:\/\/www.prglab.com\/blog\/cplusplus-tutorial\/compound-data\/pointers","title":{"rendered":"\u6307\u9488"},"content":{"rendered":"\n<h2>3.3 \u6307\u9488 \uff08Pointers\uff09<\/h2>\n\n\n\n<p>\u6211\u4eec\u5df2\u7ecf\u660e\u767d\u53d8\u91cf\u5176\u5b9e\u662f\u53ef\u4ee5\u7531\u6807\u8bc6\u6765\u5b58\u53d6\u7684\u5185\u5b58\u5355\u5143\u3002\u4f46\u8fd9\u4e9b\u53d8\u91cf\u5b9e\u9645\u4e0a\u662f\u5b58\u50a8\u5728\u5185\u5b58\u4e2d\u5177\u4f53\u7684\u4f4d\u7f6e\u4e0a\u7684\u3002\u5bf9\u6211\u4eec\u7684\u7a0b\u5e8f\u6765\u8bf4\uff0c\u8ba1\u7b97\u673a\u5185\u5b58\u53ea\u662f\u4e00\u4e32\u8fde\u7eed\u7684\u5355\u5b57\u8282\u5355\u5143(1byte cell)\uff0c\u5373\u6700\u5c0f\u6570\u636e\u5355\u4f4d\uff0c\u6bcf\u4e00\u4e2a\u5355\u5143\u6709\u4e00\u4e2a\u552f\u4e00\u5730\u5740\u3002<\/p>\n\n\n\n<p>\u8ba1\u7b97\u673a\u5185\u5b58\u5c31\u597d\u50cf\u57ce\u5e02\u4e2d\u7684\u8857\u9053\u3002\u5728\u4e00\u6761\u8857\u4e0a\uff0c\u6240\u6709\u7684\u623f\u5b50\u88ab\u987a\u5e8f\u7f16\u53f7\uff0c\u6bcf\u6240\u623f\u5b50\u6709\u552f\u4e00\u7f16\u53f7\u3002\u56e0\u6b64\u5982\u679c\u6211\u4eec\u8bf4\u829d\u9ebb\u885727\u53f7\uff0c\u6211\u4eec\u5f88\u5bb9\u6613\u627e\u5230\u5b83\uff0c\u56e0\u4e3a\u53ea\u6709\u4e00\u6240\u623f\u5b50\u4f1a\u662f\u8fd9\u4e2a\u7f16\u53f7\uff0c\u800c\u4e14\u6211\u4eec\u77e5\u9053\u5b83\u4f1a\u572826\u53f7\u548c28\u53f7\u4e4b\u95f4\u3002<\/p>\n\n\n\n<p>\u540c\u623f\u5c4b\u6309\u8857\u9053\u5730\u5740\u7f16\u53f7\u4e00\u6837\uff0c\u64cd\u4f5c\u7cfb\u7edf(operating system)\u4e5f\u6309\u7167\u552f\u4e00\u987a\u5e8f\u7f16\u53f7\u6765\u7ec4\u7ec7\u5185\u5b58\u3002\u56e0\u6b64\uff0c\u5f53\u6211\u4eec\u8bf4\u5185\u5b58\u4e2d\u7684\u4f4d\u7f6e1776\uff0c\u6211\u4eec\u77e5\u9053\u5185\u5b58\u4e2d\u53ea\u6709\u4e00\u4e2a\u4f4d\u7f6e\u662f\u8fd9\u4e2a\u5730\u5740\uff0c\u800c\u4e14\u5b83\u5728\u5730\u57401775\u548c1777\u4e4b\u95f4\u3002<\/p>\n\n\n\n<h3>\u5730\u5740\u64cd\u4f5c\u7b26\/\u53bb\u5f15\u64cd\u4f5c\u7b26 Address\/dereference operator (&amp;)<\/h3>\n\n\n\n<p>\u5f53\u6211\u4eec\u58f0\u660e\u4e00\u4e2a\u53d8\u91cf\u7684\u540c\u65f6\uff0c\u5b83\u5fc5\u987b\u88ab\u5b58\u50a8\u5230\u5185\u5b58\u4e2d\u4e00\u4e2a\u5177\u4f53\u7684\u5355\u5143\u4e2d\u3002\u901a\u5e38\u6211\u4eec\u5e76\u4e0d\u4f1a\u6307\u5b9a\u53d8\u91cf\u88ab\u5b58\u50a8\u5230\u54ea\u4e2a\u5177\u4f53\u7684\u5355\u5143\u4e2d\u2014\u5e78\u4e8f\u8fd9\u901a\u5e38\u662f\u7531\u7f16\u8bd1\u5668\u548c\u64cd\u4f5c\u7cfb\u7edf\u81ea\u52a8\u5b8c\u6210\u7684\uff0c\u4f46\u4e00\u65e6\u64cd\u4f5c\u7cfb\u7edf\u6307\u5b9a\u4e86\u4e00\u4e2a\u5730\u5740\uff0c\u6709\u4e9b\u65f6\u5019\u6211\u4eec\u53ef\u80fd\u4f1a\u60f3\u77e5\u9053\u53d8\u91cf\u88ab\u5b58\u50a8\u5728\u54ea\u91cc\u4e86\u3002<\/p>\n\n\n\n<p>\u8fd9\u53ef\u4ee5\u901a\u8fc7\u5728\u53d8\u91cf\u6807\u8bc6\u524d\u9762\u52a0\u4e0e\u7b26\u53f7ampersand sign (&amp;)\u6765\u5b9e\u73b0\uff0c\u5b83\u8868\u793a&#8221;&#8230;\u7684\u5730\u5740&#8221; (&#8220;address of&#8221;)\uff0c\u56e0\u6b64\u79f0\u4e3a\u5730\u5740\u64cd\u4f5c\u7b26(adress operator)\uff0c\u53c8\u79f0\u53bb\u5f15\u64cd\u4f5c\u7b26(dereference operator)\u3002\u4f8b\u5982\uff1a<\/p>\n\n\n\n<p><code>ted = &amp;andy;<\/code><\/p>\n\n\n\n<p>\u5c06\u53d8\u91cfandy\u7684\u5730\u5740\u8d4b\u7ed9\u53d8\u91cfted\uff0c\u56e0\u4e3a\u5f53\u5728\u53d8\u91cf\u540d\u79f0andy \u524d\u9762\u52a0ampersand (&amp;) \u7b26\u53f7\uff0c\u6211\u4eec\u6307\u7684\u5c06\u4e0d\u518d\u662f\u8be5\u53d8\u91cf\u7684\u5185\u5bb9\uff0c\u800c\u662f\u5b83\u5728\u5185\u5b58\u4e2d\u7684\u5730\u5740\u3002<\/p>\n\n\n\n<p>\u5047\u8bbeandy \u88ab\u653e\u5728\u4e86\u5185\u5b58\u4e2d\u5730\u57401776\u7684\u5355\u5143\u4e2d\uff0c\u7136\u540e\u6211\u4eec\u6709\u4e0b\u5217\u4ee3\u7801\uff1aandy = 25;<br>fred = andy;<br>ted = &amp;andy;<\/p>\n\n\n\n<p>\u5176\u7ed3\u679c\u663e\u793a\u5728\u4e0b\u9762\u7684\u56fe\u7247\u4e2d\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img3-3-1.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u6211\u4eec\u5c06\u53d8\u91cfandy \u7684\u503c\u8d4b\u7ed9\u53d8\u91cffred\uff0c\u8fd9\u4e0e\u4ee5\u524d\u6211\u4eec\u770b\u5230\u5f88\u591a\u4f8b\u5b50\u90fd\u76f8\u540c\uff0c\u4f46\u5bf9\u4e8eted\uff0c\u6211\u4eec\u628a\u64cd\u4f5c\u7cfb\u7edf\u5b58\u50a8andy\u7684\u5185\u5b58\u5730\u5740\u8d4b\u7ed9\u5b83\uff0c\u6211\u4eec\u60f3\u50cf\u8be5\u5730\u5740\u4e3a1776 (\u5b83\u53ef\u4ee5\u662f\u4efb\u4f55\u5730\u5740\uff0c\u8fd9\u91cc\u53ea\u662f\u4e00\u4e2a\u5047\u8bbe\u7684\u5730\u5740)\uff0c\u539f\u56e0\u662f\u5f53\u7ed9ted \u8d4b\u503c\u7684\u65f6\u5019\uff0c\u6211\u4eec\u5728andy \u524d\u9762\u52a0\u4e86ampersand (&amp;) \u7b26\u53f7\u3002<\/p>\n\n\n\n<p>\u5b58\u50a8\u5176\u5b83\u53d8\u91cf\u5730\u5740\u7684\u53d8\u91cf(\u5982\u4e0a\u9762\u4f8b\u5b50\u4e2d\u7684ted )\uff0c\u6211\u4eec\u79f0\u4e4b\u4e3a\u6307\u9488(pointer)\u3002\u5728C++ \u4e2d\uff0c\u6307\u9488pointers \u6709\u5176\u7279\u5b9a\u7684\u4f18\u70b9\uff0c\u56e0\u6b64\u7ecf\u5e38\u88ab\u4f7f\u7528\u3002\u5728\u540e\u9762\u6211\u4eec\u5c06\u4f1a\u770b\u5230\u8fd9\u79cd\u53d8\u91cf\u5982\u4f55\u88ab\u58f0\u660e\u3002<\/p>\n\n\n\n<h3>\u5f15\u7528\u64cd\u4f5c\u7b26Reference operator (*)<\/h3>\n\n\n\n<p>\u4f7f\u7528\u6307\u9488\u7684\u65f6\u5019\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5728\u6307\u9488\u6807\u8bc6\u7684\u524d\u9762\u52a0\u661f\u53f7asterisk (*)\u6765\u5b58\u50a8\u8be5\u6307\u9488\u6307\u5411\u7684\u53d8\u91cf\u6240\u5b58\u50a8\u7684\u6570\u503c\uff0c\u5b83\u53ef\u4ee5\u88ab\u7ffb\u8bd1\u4e3a\u201c\u6240\u6307\u5411\u7684\u6570\u503c\u201d\uff08&#8221;value pointed by&#8221;\uff09\u3002\u56e0\u6b64\uff0c\u4ecd\u7528\u524d\u9762\u4f8b\u5b50\u4e2d\u7684\u6570\u503c\uff0c\u5982\u679c\u6211\u4eec\u5199\uff1a beth = *ted; (\u6211\u4eec\u53ef\u4ee5\u8bfb\u4f5c\uff1a&#8221;beth \u7b49\u4e0eted\u6240\u6307\u5411\u7684\u6570\u503c&#8221;) beth \u5c06\u4f1a\u83b7\u5f97\u6570\u503c25\uff0c\u56e0\u4e3ated \u662f1776\uff0c\u800c1776 \u6240\u6307\u5411\u7684\u6570\u503c\u4e3a25\u3002<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img3-3-2.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u4f60\u5fc5\u987b\u6e05\u695a\u7684\u533a\u5206ted \u5b58\u50a8\u7684\u662f1776\uff0c\u4f46*ted (\u524d\u9762\u52a0asterisk * ) \u6307\u7684\u662f\u5730\u57401776\u4e2d\u5b58\u50a8\u7684\u6570\u503c\uff0c\u537325\u3002\u6ce8\u610f\u52a0\u6216\u4e0d\u52a0\u661f\u53f7*\u7684\u4e0d\u540c(\u4e0b\u9762\u4ee3\u7801\u4e2d\u6ce8\u91ca\u663e\u793a\u4e86\u5982\u4f55\u8bfb\u8fd9\u4e24\u4e2a\u4e0d\u540c\u7684\u8868\u8fbe\u5f0f):beth = ted;&nbsp;\/\/ beth \u7b49\u4e8e ted ( 1776 )<br>beth = *ted;&nbsp;\/\/ beth \u7b49\u4e8e ted \u6240\u6307\u5411\u7684\u6570\u503c ( 25 )<\/p>\n\n\n\n<p><strong>\u5730\u5740\u6216\u53cd\u5f15\u7528\u64cd\u4f5c\u7b26Operator of address or dereference (&amp;)<\/strong><\/p>\n\n\n\n<p>\u5b83\u88ab\u7528\u4f5c\u4e00\u4e2a\u53d8\u91cf\u524d\u7f00\uff0c\u53ef\u4ee5\u88ab\u7ffb\u8bd1\u4e3a\u201c\u2026\u7684\u5730\u5740\u201d(&#8220;address of&#8221;)\uff0c\u56e0\u6b64\uff1a&amp;variable1 \u53ef\u4ee5\u88ab\u8bfb\u4f5c variable1\u7684\u5730\u5740(&#8220;address of variable1&#8221; )\u3002<\/p>\n\n\n\n<p><strong>\u5f15\u7528\u64cd\u4f5c\u7b26Operator of reference (*)<\/strong><\/p>\n\n\n\n<p>\u5b83\u8868\u793a\u8981\u53d6\u7684\u662f\u8868\u8fbe\u5f0f\u6240\u8868\u793a\u7684\u5730\u5740\u6307\u5411\u7684\u5185\u5bb9\u3002\u5b83\u53ef\u4ee5\u88ab\u7ffb\u8bd1\u4e3a\u201c\u2026\u6307\u5411\u7684\u6570\u503c\u201d (&#8220;value pointed by&#8221;)\u3002<\/p>\n\n\n\n<p>* mypointer \u53ef\u4ee5\u88ab\u8bfb\u4f5c &#8220;mypointer\u6307\u5411\u7684\u6570\u503c&#8221;\u3002<\/p>\n\n\n\n<p>\u7ee7\u7eed\u4f7f\u7528\u4e0a\u9762\u5f00\u59cb\u7684\u4f8b\u5b50\uff0c\u770b\u4e0b\u9762\u7684\u4ee3\u7801\uff1aandy = 25;<br>ted = &amp;andy;<\/p>\n\n\n\n<p>\u73b0\u5728\u4f60\u5e94\u8be5\u53ef\u4ee5\u6e05\u695a\u7684\u770b\u5230\u4ee5\u4e0b\u7b49\u5f0f\u5168\u90e8\u6210\u7acb\uff1aandy == 25<br>&amp;andy == 1776<br>ted == 1776<br>*ted == 25<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u8868\u8fbe\u5f0f\u5f88\u5bb9\u6613\u7406\u89e3\uff0c\u56e0\u4e3a\u6211\u4eec\u6709\u8d4b\u503c\u8bed\u53e5andy=25;\u3002\u7b2c\u4e8c\u4e2a\u8868\u8fbe\u5f0f\u4f7f\u7528\u4e86\u5730\u5740\uff08\u6216\u53cd\u5f15\u7528\uff09\u64cd\u4f5c\u7b26(&amp;) \u6765\u8fd4\u56de\u53d8\u91cfandy\u7684\u5730\u5740\uff0c\u5373 1776\u3002\u7b2c\u4e09\u4e2a\u8868\u8fbe\u5f0f\u5f88\u660e\u663e\u6210\u7acb\uff0c\u56e0\u4e3a\u7b2c\u4e8c\u4e2a\u8868\u8fbe\u5f0f\u4e3a\u771f\uff0c\u800c\u6211\u4eec\u7ed9ted\u8d4b\u503c\u7684\u8bed\u53e5\u4e3ated = &amp;andy;\u3002\u7b2c\u56db\u4e2a\u8868\u8fbe\u5f0f\u4f7f\u7528\u4e86\u5f15\u7528\u64cd\u4f5c\u7b26 (*)\uff0c\u76f8\u5f53\u4e8eted\u6307\u5411\u7684\u5730\u5740\u4e2d\u5b58\u50a8\u7684\u6570\u503c\uff0c\u537325\u3002<\/p>\n\n\n\n<p>\u7531\u6b64\u4f60\u4e5f\u53ef\u4ee5\u63a8\u65ad\u51fa\uff0c\u53ea\u8981ted \u6240\u6307\u5411\u7684\u5730\u5740\u4e2d\u5b58\u50a8\u7684\u6570\u503c\u4e0d\u53d8\uff0c\u4ee5\u4e0b\u8868\u8fbe\u5f0f\u4e5f\u4e3a\u771f\uff1a<\/p>\n\n\n\n<p><code>*ted == andy<\/code><\/p>\n\n\n\n<h3>\u58f0\u660e\u6307\u9488\u578b\u53d8\u91cfDeclaring variables of type pointer<\/h3>\n\n\n\n<p>\u7531\u4e8e\u6307\u9488\u53ef\u4ee5\u76f4\u63a5\u5f15\u7528\u5b83\u6240\u6307\u5411\u7684\u6570\u503c\uff0c\u56e0\u6b64\u6709\u5fc5\u8981\u5728\u58f0\u660e\u6307\u9488\u7684\u65f6\u5019\u6307\u660e\u5b83\u6240\u6307\u5411\u7684\u6570\u636e\u7c7b\u578b\u3002\u6307\u5411\u4e00\u4e2a\u6574\u578bint\u6216\u6d6e\u70b9\u578bfloat\u6570\u636e\u7684\u6307\u9488\u4e0e\u6307\u5411\u4e00\u4e2a\u5b57\u7b26\u578bchar\u6570\u636e\u7684\u6307\u9488\u5e76\u4e0d\u76f8\u540c\u3002<\/p>\n\n\n\n<p>\u56e0\u6b64\uff0c\u58f0\u660e\u6307\u9488\u7684\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<p><code>type * pointer_name;<\/code><\/p>\n\n\n\n<p>\u8fd9\u91cc\uff0ctype \u662f\u6307\u9488\u6240\u6307\u5411\u7684\u6570\u636e\u7684\u7c7b\u578b\uff0c\u800c\u4e0d\u662f\u6307\u9488\u81ea\u5df1\u7684\u7c7b\u578b\u3002\u4f8b\u5982\uff1aint * number;<br>char * character;<br>float * greatnumber;<\/p>\n\n\n\n<p>\u5b83\u4eec\u662f3\u4e2a\u6307\u9488\u7684\u58f0\u660e\uff0c\u6bcf\u4e00\u4e2a\u6307\u9488\u6307\u5411\u4e00\u79cd\u4e0d\u540c\u6570\u636e\u7c7b\u578b\u3002\u8fd9\u4e09\u4e2a\u6307\u9488\u672c\u8eab\u5176\u5b9e\u5728\u5185\u5b58\u4e2d\u5360\u7528\u540c\u6837\u5927\u5c0f\u7684\u5185\u5b58\u7a7a\u95f4\uff08\u6307\u9488\u7684\u5927\u5c0f\u53d6\u51b3\u4e8e\u4e0d\u540c\u7684\u64cd\u4f5c\u7cfb\u7edf\uff09\uff0c\u4f46\u5b83\u4eec\u6240\u6307\u5411\u7684\u6570\u636e\u662f\u4e0d\u540c\u7684\u7c7b\u578b\uff0c\u5e76\u5360\u7528\u4e0d\u540c\u5927\u5c0f\u7684\u5185\u5b58\u7a7a\u95f4\uff0c\u4e00\u4e2a\u662f\u6574\u578bint\uff0c\u4e00\u4e2a\u662f\u5b57\u7b26\u578bchar \uff0c\u8fd8\u6709\u4e00\u4e2a\u662f\u6d6e\u70b9\u578bfloat\u3002<\/p>\n\n\n\n<p>\u9700\u8981\u5f3a\u8c03\u7684\u4e00\u70b9\u662f\uff0c\u5728\u6307\u9488\u58f0\u660e\u65f6\u7684\u661f\u53f7asterisk (*) \u4ec5\u8868\u793a\u8fd9\u91cc\u58f0\u660e\u7684\u662f\u4e00\u4e2a\u6307\u9488\uff0c\u4e0d\u8981\u628a\u5b83\u548c\u524d\u9762\u6211\u4eec\u7528\u8fc7\u7684\u5f15\u7528\u64cd\u4f5c\u7b26\u6df7\u6dc6\uff0c\u867d\u7136\u90a3\u4e5f\u662f\u5199\u6210\u4e00\u4e2a\u661f\u53f7 (*)\u3002\u5b83\u4eec\u53ea\u662f\u7528\u540c\u4e00\u7b26\u53f7\u8868\u793a\u7684\u4e24\u4e2a\u4e0d\u540c\u4efb\u52a1\u3002<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>\/\/ my first pointer<br>#include &lt;iostream.h&gt;<br><br>int main ( ) {<br>int value1 = 5, value2 = 15;<br>int * mypointer;<br>mypointer = &amp;value1;<br>*mypointer = 10;<br>mypointer = &amp;value2;<br>*mypointer = 20;<br>cout &lt;&lt; &#8220;value1==&#8221; &lt;&lt; value1 &lt;&lt; &#8220;\/ value2==&#8221; &lt;&lt; value2;<br>return 0;<br>}<\/td><td>value1==10 \/ value2==20<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u6ce8\u610f\u53d8\u91cfvalue1 \u548c value2 \u662f\u600e\u6837\u95f4\u63a5\u7684\u88ab\u6539\u53d8\u6570\u503c\u7684\u3002\u9996\u5148\u6211\u4eec\u4f7f\u7528 ampersand sign (&amp;) \u5c06value1\u7684\u5730\u5740\u8d4b\u7ed9mypointer \u3002\u7136\u540e\u6211\u4eec\u5c0610 \u8d4b\u7ed9 mypointer\u6240\u6307\u5411\u7684\u6570\u503c\uff0c\u5b83\u5176\u5b9e\u6307\u5411value1\u7684\u5730\u5740\uff0c\u56e0\u6b64\uff0c\u6211\u4eec\u95f4\u63a5\u7684\u4fee\u6539\u4e86value1\u7684\u6570\u503c\u3002<\/p>\n\n\n\n<p>\u4e3a\u4e86\u8ba9\u4f60\u4e86\u89e3\u5728\u540c\u4e00\u4e2a\u7a0b\u5e8f\u4e2d\u4e00\u4e2a\u6307\u9488\u53ef\u4ee5\u88ab\u7528\u4f5c\u4e0d\u540c\u7684\u6570\u503c\uff0c\u6211\u4eec\u5728\u8fd9\u4e2a\u7a0b\u5e8f\u4e2d\u7528value2 \u548c\u540c\u4e00\u4e2a\u6307\u9488\u91cd\u590d\u4e86\u4e0a\u9762\u7684\u8fc7\u7a0b\u3002<\/p>\n\n\n\n<p>\u4e0b\u9762\u662f\u4e00\u4e2a\u66f4\u590d\u6742\u4e00\u4e9b\u7684\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>\/\/ more pointers<br>#include &lt;iostream.h&gt;<br><br>int main () {<br>int value1 = 5, value2 = 15;<br>int *p1, *p2;<br>p1 = &amp;value1;&nbsp;\/\/ p1 = address of value1<br>p2 = &amp;value2;&nbsp;\/\/ p2 = address of value2<br>*p1 = 10;&nbsp;\/\/ value pointed by p1 = 10<br>*p2 = *p1;&nbsp;\/\/ value pointed by p2 = value pointed by p1<br>p1 = p2;&nbsp;\/\/ p1 = p2 (value of pointer copied)<br>*p1 = 20;&nbsp;\/\/ value pointed by p1 = 20<br>cout &lt;&lt; &#8220;value1==&#8221; &lt;&lt; value1 &lt;&lt; &#8220;\/ value2==&#8221; &lt;&lt; value2;<br>return 0;<br>}<\/td><td>value1==10 \/ value2==20<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u4e0a\u9762\u6bcf\u4e00\u884c\u90fd\u6709\u6ce8\u91ca\u8bf4\u660e\u4ee3\u7801\u7684\u610f\u601d\uff1aampersand (&amp;) \u4e3a&#8221;address of&#8221;\uff0casterisk (*) \u4e3a &#8220;value pointed by&#8221;\u3002\u6ce8\u610f\u6709\u4e9b\u5305\u542bp1 \u548cp2 \u7684\u8868\u8fbe\u5f0f\u4e0d\u5e26\u661f\u53f7\u3002\u52a0\u4e0d\u52a0\u661f\u53f7\u7684\u542b\u4e49\u5341\u5206\u4e0d\u540c\uff1a\u661f\u53f7(*)\u540e\u9762\u8ddf\u6307\u9488\u540d\u79f0\u8868\u793a\u6307\u9488\u6240\u6307\u5411\u7684\u5730\u65b9\uff0c\u800c\u6307\u9488\u540d\u79f0\u4e0d\u52a0\u661f\u53f7(*)\u8868\u793a\u6307\u9488\u672c\u8eab\u7684\u6570\u503c\uff0c\u5373\u5b83\u6240\u6307\u5411\u7684\u5730\u65b9\u7684\u5730\u5740\u3002<\/p>\n\n\n\n<p>\u53e6\u4e00\u4e2a\u9700\u8981\u6ce8\u610f\u7684\u5730\u65b9\u662f\u8fd9\u4e00\u884c\uff1a<\/p>\n\n\n\n<p><code>int *p1, *p2;<\/code><\/p>\n\n\n\n<p>\u58f0\u660e\u4e86\u4e0a\u4f8b\u7528\u5230\u7684\u4e24\u4e2a\u6307\u9488\uff0c\u6bcf\u4e2a\u5e26\u4e00\u4e2a\u661f\u53f7(*)\uff0c\u56e0\u4e3a\u662f\u8fd9\u4e00\u884c\u5b9a\u4e49\u7684\u6240\u6709\u6307\u9488\u90fd\u662f\u6574\u578bint (\u800c\u4e0d\u662f int*)\u3002\u539f\u56e0\u662f\u5f15\u7528\u64cd\u4f5c\u7b26(*) \u7684\u4f18\u5148\u7ea7\u987a\u5e8f\u4e0e\u7c7b\u578b\u58f0\u660e\u7684\u76f8\u540c\uff0c\u56e0\u6b64\uff0c\u7531\u4e8e\u5b83\u4eec\u90fd\u662f\u5411\u53f3\u7ed3\u5408\u7684\u64cd\u4f5c\uff0c\u661f\u53f7\u88ab\u4f18\u5148\u8ba1\u7b97\u3002\u6211\u4eec\u5728&nbsp;<a href=\"http:\/\/www.prglab.com\/cms\/pages\/c-tutorial\/c-basics\/operators.php\">section 1.3: Operators<\/a>&nbsp;\u4e2d\u5df2\u7ecf\u8ba8\u8bba\u8fc7\u8fd9\u4e9b\u3002\u6ce8\u610f\u5728\u58f0\u660e\u6bcf\u4e00\u4e2a\u6307\u9488\u7684\u65f6\u5019\u524d\u9762\u52a0\u4e0a\u661f\u53f7asterisk (*)\u3002<\/p>\n\n\n\n<h3>\u6307\u9488\u548c\u6570\u7ec4Pointers and arrays<\/h3>\n\n\n\n<p>\u6570\u7ec4\u7684\u6982\u5ff5\u4e0e\u6307\u9488\u7684\u6982\u5ff5\u8054\u7cfb\u975e\u5e38\u89e3\u5bc6\u3002\u5176\u5b9e\u6570\u7ec4\u7684\u6807\u8bc6\u76f8\u5f53\u4e8e\u5b83\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u7684\u5730\u5740\uff0c\u5c31\u50cf\u4e00\u4e2a\u6307\u9488\u76f8\u5f53\u4e8e\u5b83\u6240\u6307\u5411\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u7684\u5730\u5740\uff0c\u56e0\u6b64\u5176\u5b9e\u5b83\u4eec\u662f\u540c\u4e00\u4e2a\u4e1c\u897f\u3002\u4f8b\u5982\uff0c\u5047\u8bbe\u6211\u4eec\u6709\u4ee5\u4e0b\u58f0\u660e\uff1aint numbers [20];<br>int * p;<\/p>\n\n\n\n<p>\u4e0b\u9762\u7684\u8d4b\u503c\u4e3a\u5408\u6cd5\u7684\uff1a<\/p>\n\n\n\n<p><code>p = numbers;<\/code><\/p>\n\n\n\n<p>\u8fd9\u91cc\u6307\u9488p \u548cnumbers \u662f\u7b49\u4ef7\u7684\uff0c\u5b83\u4eec\u6709\u76f8\u540c\u7684\u5c5e\u6027\uff0c\u552f\u4e00\u7684\u4e0d\u540c\u662f\u6211\u4eec\u53ef\u4ee5\u7ed9\u6307\u9488p\u8d4b\u5176\u5b83\u7684\u6570\u503c\uff0c\u800cnumbers \u603b\u662f\u6307\u5411\u88ab\u5b9a\u4e49\u768420\u4e2a\u6574\u6570\u7ec4\u4e2d\u7684\u7b2c\u4e00\u4e2a\u3002\u6240\u4ee5\uff0cp\u53ea\u662f\u4e00\u4e2a\u666e\u901a\u7684\u6307\u9488\u53d8\u91cf\uff0c\u800c\u4e0e\u4e4b\u4e0d\u540c\uff0cnumbers \u662f\u4e00\u4e2a\u6307\u9488\u5e38\u91cf(constant pointer)\uff0c\u6570\u7ec4\u540d\u7684\u786e\u662f\u4e00\u4e2a\u6307\u9488\u5e38\u91cf\u3002\u56e0\u6b64\u867d\u7136\u524d\u9762\u7684\u8d4b\u503c\u8868\u8fbe\u5f0f\u662f\u5408\u6cd5\u7684\uff0c\u4f46\u4e0b\u9762\u7684\u4e0d\u662f\uff1a<\/p>\n\n\n\n<p><code>numbers = p;<\/code><\/p>\n\n\n\n<p>\u56e0\u4e3anumbers \u662f\u4e00\u4e2a\u6570\u7ec4(\u6307\u9488\u5e38\u91cf)\uff0c\u5e38\u91cf\u6807\u8bc6\u4e0d\u53ef\u4ee5\u88ab\u8d4b\u5176\u5b83\u6570\u503c\u3002<\/p>\n\n\n\n<p>\u7531\u4e8e\u53d8\u91cf\u7684\u7279\u6027\uff0c\u4ee5\u4e0b\u4f8b\u5b50\u4e2d\u6240\u6709\u5305\u542b\u6307\u9488\u7684\u8868\u8fbe\u5f0f\u90fd\u662f\u5408\u6cd5\u7684\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>\/\/ more pointers<br>#include &lt;iostream.h&gt;<br><br>int main () {<br>int numbers[5];<br>int * p;<br>p = numbers;<br>*p = 10;<br>p++;<br>*p = 20;<br>p = &amp;numbers[2];<br>*p = 30;<br>p = numbers + 3;<br>*p = 40;<br>p = numbers;<br>*(p+4) = 50;<br>for (int n=0; n&lt;5; n++)<br>cout &lt;&lt; numbers[n] &lt;&lt; &#8220;, &#8220;;<br>return 0;<br>}<\/td><td>10, 20, 30, 40, 50,<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5728\u6570\u7ec4\u4e00\u7ae0\u4e2d\u6211\u4eec\u4f7f\u7528\u4e86\u62ec\u53f7[]\u6765\u6307\u660e\u6211\u4eec\u8981\u5f15\u7528\u7684\u6570\u7ec4\u5143\u7d20\u7684\u7d22\u5f15(index)\u3002\u4e2d\u62ec\u53f7[]\u4e5f\u53eb\u4f4d\u79fb(offset)\u64cd\u4f5c\u7b26\uff0c\u5b83\u76f8\u5f53\u4e8e\u5728\u6307\u9488\u4e2d\u7684\u5730\u5740\u4e0a\u52a0\u4e0a\u62ec\u53f7\u4e2d\u7684\u6570\u5b57\u3002\u4f8b\u5982\uff0c\u4e0b\u9762\u4e24\u4e2a\u8868\u8fbe\u5f0f\u4e92\u76f8\u7b49\u4ef7\uff1aa[5] = 0;&nbsp;\/\/ a [offset of 5] = 0<br>*(a+5) = 0;&nbsp;\/\/ pointed by (a+5) = 0<\/p>\n\n\n\n<p>\u4e0d\u7ba1a \u662f\u4e00\u4e2a\u6307\u9488\u8fd8\u662f\u4e00\u4e2a\u6570\u7ec4\u540d\uff0c \u8fd9\u4e24\u4e2a\u8868\u8fbe\u5f0f\u90fd\u662f\u5408\u6cd5\u7684\u3002<\/p>\n\n\n\n<h3>\u6307\u9488\u521d\u59cb\u5316Pointer initialization<\/h3>\n\n\n\n<p>\u5f53\u58f0\u660e\u4e00\u4e2a\u6307\u9488\u7684\u65f6\u5019\u6211\u4eec\u53ef\u80fd\u9700\u8981\u540c\u65f6\u6307\u5b9a\u5b83\u4eec\u6307\u5411\u54ea\u4e2a\u53d8\u91cf\uff0cint number;<br>int *tommy = &amp;number;<\/p>\n\n\n\n<p>\u8fd9\u76f8\u5f53\u4e8e\uff1aint number;<br>int *tommy;<br>tommy = &amp;number;<\/p>\n\n\n\n<p>\u5f53\u7ed9\u4e00\u4e2a\u6307\u9488\u8d4b\u503c\u7684\u65f6\u5019\uff0c\u6211\u4eec\u603b\u662f\u8d4b\u7ed9\u5b83\u4e00\u4e2a\u5730\u5740\u503c\uff0c\u800c\u4e0d\u662f\u5b83\u6240\u6307\u5411\u6570\u636e\u7684\u503c\u3002\u4f60\u5fc5\u987b\u8003\u8651\u5230\u5728\u58f0\u660e\u4e00\u4e2a\u6307\u9488\u7684\u65f6\u5019\uff0c\u661f\u53f7 (*) \u53ea\u662f\u7528\u6765\u6307\u660e\u5b83\u662f\u6307\u9488\uff0c\u800c\u4ece\u4e0d\u8868\u793a\u5f15\u7528\u64cd\u4f5c\u7b26reference operator (*)\u3002\u8bb0\u4f4f\uff0c\u5b83\u4eec\u662f\u4e24\u79cd\u4e0d\u540c\u64cd\u4f5c\uff0c\u867d\u7136\u5b83\u4eec\u5199\u6210\u540c\u6837\u7684\u7b26\u53f7\u3002\u56e0\u6b64\uff0c\u6211\u4eec\u8981\u6ce8\u610f\u4e0d\u8981\u5c06\u4ee5\u4e0a\u7684\u4ee3\u7801\u4e0e\u4e0b\u9762\u7684\u4ee3\u7801\u6df7\u6dc6\uff1aint number;<br>int *tommy;<br>*tommy = &amp;number;<\/p>\n\n\n\n<p>\u8fd9\u4e9b\u4ee3\u7801\u4e5f\u6ca1\u6709\u4ec0\u4e48\u5b9e\u9645\u610f\u4e49\u3002<\/p>\n\n\n\n<p>\u5728\u5b9a\u4e49\u6570\u7ec4\u6307\u9488\u7684\u65f6\u5019\uff0c\u7f16\u8bd1\u5668\u5141\u8bb8\u6211\u4eec\u5728\u58f0\u660e\u53d8\u91cf\u6307\u9488\u7684\u540c\u65f6\u5bf9\u6570\u7ec4\u8fdb\u884c\u521d\u59cb\u5316\uff0c\u521d\u59cb\u5316\u7684\u5185\u5bb9\u9700\u8981\u662f\u5e38\u91cf\uff0c\u4f8b\u5982\uff1a<\/p>\n\n\n\n<p><code>char * terry = \"hello\";<\/code><\/p>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c\u5185\u5b58\u4e2d\u9884\u7559\u4e86\u5b58\u50a8&#8221;hello&#8221; \u7684\u7a7a\u95f4\uff0c\u5e76\u4e14terry\u88ab\u8d4b\u4e88\u4e86\u5411\u8fd9\u4e2a\u5185\u5b58\u5757\u7684\u7b2c\u4e00\u4e2a\u5b57\u7b26\uff08\u5bf9\u5e94\u2019h\u2019\uff09\u7684\u6307\u9488\u3002\u5047\u8bbe&#8221;hello&#8221;\u5b58\u50a8\u5728\u5730\u57401702\uff0c\u4e0b\u56fe\u663e\u793a\u4e86\u4e0a\u9762\u7684\u5b9a\u4e49\u5728\u5185\u5b58\u4e2d\u72b6\u6001\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img3-3-3.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u8fd9\u91cc\u9700\u8981\u5f3a\u8c03\uff0cterry \u5b58\u50a8\u7684\u662f\u6570\u503c1702 \uff0c\u800c\u4e0d\u662f&#8217;h&#8217; \u6216 &#8220;hello&#8221;\uff0c\u867d\u71361702 \u6307\u5411\u8fd9\u4e9b\u5b57\u7b26\u3002<\/p>\n\n\n\n<p>\u6307\u9488terry \u6307\u5411\u4e00\u4e2a\u5b57\u7b26\u4e32\uff0c\u53ef\u4ee5\u88ab\u5f53\u4f5c\u6570\u7ec4\u4e00\u6837\u4f7f\u7528\uff08\u6570\u7ec4\u53ea\u662f\u4e00\u4e2a\u5e38\u91cf\u6307\u9488\uff09\u3002\u4f8b\u5982\uff0c\u5982\u679c\u6211\u4eec\u7684\u5fc3\u60c5\u53d8\u4e86\uff0c\u800c\u60f3\u628aterry\u6307\u5411\u7684\u5185\u5bb9\u4e2d\u7684\u5b57\u7b26&#8217;o&#8217; \u53d8\u4e3a\u7b26\u53f7&#8217;!&#8217; \uff0c\u6211\u4eec\u53ef\u4ee5\u7528\u4ee5\u4e0b\u4e24\u79cd\u65b9\u5f0f\u7684\u4efb\u4f55\u4e00\u79cd\u6765\u5b9e\u73b0\uff1aterry[4] = &#8216;!&#8217;;<br>*(terry+4) = &#8216;!&#8217;;<\/p>\n\n\n\n<p>\u8bb0\u4f4f\u5199 terry[4] \u4e0e*(terry+4)\u662f\u4e00\u6837\u7684\uff0c\u867d\u7136\u7b2c\u4e00\u79cd\u8868\u8fbe\u65b9\u5f0f\u66f4\u5e38\u7528\u4e00\u4e9b\u3002\u4ee5\u4e0a\u4e24\u4e2a\u8868\u8fbe\u5f0f\u90fd\u4f1a\u5b9e\u73b0\u4ee5\u4e0b\u6539\u53d8\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img3-3-4.gif\" alt=\"\"\/><\/figure>\n\n\n\n<h3>\u6307\u9488\u7684\u6570\u5b66\u8fd0\u7b97Arithmetic of pointers<\/h3>\n\n\n\n<p>\u5bf9\u6307\u9488\u8fdb\u884c\u6570\u5b66\u8fd0\u7b97\u4e0e\u5176\u4ed6\u6574\u578b\u6570\u636e\u7c7b\u578b\u8fdb\u884c\u6570\u5b66\u8fd0\u7b97\u7a0d\u6709\u4e0d\u540c\u3002\u9996\u5148\uff0c\u5bf9\u6307\u9488\u53ea\u6709\u52a0\u6cd5\u548c\u51cf\u6cd5\u8fd0\u7b97\uff0c\u5176\u5b83\u8fd0\u7b97\u5728\u6307\u9488\u4e16\u754c\u91cc\u6ca1\u6709\u610f\u4e49\u3002\u4f46\u662f\u6307\u9488\u7684\u52a0\u6cd5\u548c\u51cf\u6cd5\u7684\u5177\u4f53\u8fd0\u7b97\u6839\u636e\u5b83\u6240\u6307\u5411\u7684\u6570\u636e\u7684\u7c7b\u578b\u7684\u5927\u5c0f\u7684\u4e0d\u540c\u800c\u6709\u6240\u4e0d\u540c\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u77e5\u9053\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b\u5728\u5185\u5b58\u4e2d\u5360\u7528\u7684\u5b58\u50a8\u7a7a\u95f4\u662f\u4e0d\u4e00\u6837\u7684\u3002\u4f8b\u5982\uff0c\u5bf9\u4e8e\u6574\u578b\u6570\u636e\uff0c\u5b57\u7b26char \u5360\u75281 \u7684\u5b57\u8282(1 byte)\uff0c\u77ed\u6574\u578bshort \u5360\u75282 \u4e2a\u5b57\u8282\uff0c\u957f\u6574\u578blong \u5360\u75284\u4e2a\u5b57\u8282\u3002<\/p>\n\n\n\n<p>\u5047\u8bbe\u6211\u4eec\u67093\u4e2a\u6307\u9488\uff1achar *mychar;<br>short *myshort;<br>long *mylong;<\/p>\n\n\n\n<p>\u800c\u4e14\u6211\u4eec\u77e5\u9053\u4ed6\u4eec\u5206\u522b\u6307\u5411\u5185\u5b58\u5730\u57401000, 2000 \u548c3000\u3002<\/p>\n\n\n\n<p>\u56e0\u6b64\u5982\u679c\u6211\u4eec\u6709\u4ee5\u4e0b\u4ee3\u7801\uff1amychar++;<br>myshort++;<br>mylong++;<\/p>\n\n\n\n<p>\u5c31\u50cf\u4f60\u53ef\u80fd\u60f3\u5230\u7684\uff0cmychar\u7684\u503c\u5c06\u4f1a\u53d8\u4e3a1001\u3002\u800cmyshort \u7684\u503c\u5c06\u4f1a\u53d8\u4e3a2002\uff0cmylong\u7684\u503c\u5c06\u4f1a\u53d8\u4e3a3004\u3002\u539f\u56e0\u662f\u5f53\u6211\u4eec\u7ed9\u6307\u9488\u52a0\uff11\u65f6\uff0c\u6211\u4eec\u5b9e\u9645\u662f\u8ba9\u8be5\u6307\u9488\u6307\u5411\u4e0b\u4e00\u4e2a\u4e0e\u5b83\u88ab\u5b9a\u4e49\u7684\u6570\u636e\u7c7b\u578b\u7684\u76f8\u540c\u7684\u5143\u7d20\u3002\u56e0\u6b64\uff0c\u5b83\u6240\u6307\u5411\u7684\u6570\u636e\u7c7b\u578b\u7684\u957f\u5ea6\u5b57\u8282\u6570\u5c06\u4f1a\u88ab\u52a0\u5230\u6307\u9488\u7684\u6570\u503c\u4e0a\u3002\u4ee5\u4e0a\u8fc7\u7a0b\u53ef\u4ee5\u7531\u4e0b\u56fe\u8868\u793a\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img3-3-5.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>\u8fd9\u4e00\u70b9\u5bf9\u6307\u9488\u7684\u52a0\u6cd5\u548c\u51cf\u6cd5\u8fd0\u7b97\u90fd\u9002\u7528\u3002\u5982\u679c\u6211\u4eec\u5199\u4ee5\u4e0b\u4ee3\u7801\uff0c\u5b83\u4eec\u4e0e\u4e0a\u9762\u4f8b\u5b50\u7684\u4f5c\u7528\u4e00\u62b9\u4e00\u6837\uff1a mychar = mychar + 1;myshort = myshort + 1;<br>mylong = mylong + 1;<\/p>\n\n\n\n<p>\u8fd9\u91cc\u9700\u8981\u63d0\u9192\u4f60\u7684\u662f\uff0c\u9012\u589e (++) \u548c\u9012\u51cf (&#8211;) \u64cd\u4f5c\u7b26\u6bd4\u5f15\u7528\u64cd\u4f5c\u7b26reference operator (*)\u6709\u66f4\u9ad8\u7684\u4f18\u5148\u7ea7\uff0c\u56e0\u6b64\uff0c\u4ee5\u4e0b\u7684\u8868\u8fbe\u5f0f\u6709\u53ef\u80fd\u5f15\u8d77\u6b67\u4e49\uff1a*p++;<br>*p++ = *q++;<\/p>\n\n\n\n<p>\u7b2c\u4e00\u4e2a\u8868\u8fbe\u5f0f\u7b49\u540c\u4e8e*(p++) \uff0c\u5b83\u6240\u4f5c\u7684\u662f\u589e\u52a0p (\u5b83\u6240\u6307\u5411\u7684\u5730\u5740\uff0c\u800c\u4e0d\u662f\u5b83\u5b58\u50a8\u7684\u6570\u503c)\u3002<\/p>\n\n\n\n<p>\u5728\u7b2c\u4e8c\u4e2a\u8868\u8fbe\u5f0f\u4e2d\uff0c\u56e0\u4e3a\u4e24\u4e2a\u9012\u589e\u64cd\u4f5c(++) \u90fd\u662f\u5728\u6574\u4e2a\u8868\u8fbe\u5f0f\u88ab\u8ba1\u7b97\u4e4b\u540e\u8fdb\u884c\u800c\u4e0d\u662f\u5728\u4e4b\u524d\uff0c\u6240\u4ee5*q \u7684\u503c\u9996\u5148\u88ab\u8d4b\u4e88*p \uff0c\u7136\u540eq \u548cp \u90fd\u589e\u52a01\u3002\u5b83\u76f8\u5f53\u4e8e\uff1a*p = *q;<br>p++;<br>q++;<\/p>\n\n\n\n<p>\u50cf\u901a\u5e38\u4e00\u6837\uff0c\u6211\u4eec\u5efa\u8bae\u4f7f\u7528\u62ec\u53f7()\u4ee5\u907f\u514d\u610f\u60f3\u4e0d\u5230\u7684\u7ed3\u679c\u3002<\/p>\n\n\n\n<h3>\u6307\u9488\u7684\u6307\u9488Pointers to pointers<\/h3>\n\n\n\n<p>C++ \u5141\u8bb8\u4f7f\u7528\u6307\u5411\u6307\u9488\u7684\u6307\u9488\u3002\u8981\u505a\u5230\u8fd9\u4e00\u70b9\uff0c\u6211\u4eec\u53ea\u9700\u8981\u5728\u6bcf\u4e00\u5c42\u5f15\u7528\u4e4b\u524d\u52a0\u661f\u53f7(*)\u5373\u53ef\uff1achar a;<br>char * b;<br>char ** c;<br>a = &#8216;z&#8217;;<br>b = &amp;a;<br>c = &amp;b;<\/p>\n\n\n\n<p>\u5047\u8bbe\u968f\u673a\u9009\u62e9\u5185\u5b58\u5730\u5740\u4e3a7230, 8092 \u548c10502\uff0c\u4ee5\u4e0a\u4f8b\u5b50\u53ef\u4ee5\u7528\u4e0b\u56fe\u8868\u793a\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><img src=\"http:\/\/www.prglab.com\/cms\/media\/images\/cplusplus\/img3-3-6.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>(\u65b9\u6846\u5185\u4e3a\u53d8\u91cf\u7684\u5185\u5bb9\uff1b\u65b9\u6846\u4e0b\u9762\u4e3a\u5185\u5b58\u5730\u5740)<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\u65b0\u7684\u5143\u7d20\u662f\u53d8\u91cfc\uff0c\u5173\u4e8e\u5b83\u6211\u4eec\u53ef\u4ee5\u4ece3\u4e2a\u65b9\u9762\u6765\u8ba8\u8bba\uff0c\u6bcf\u4e00\u4e2a\u65b9\u9762\u5bf9\u5e94\u4e86\u4e0d\u540c\u7684\u6570\u503c\uff1a<\/p>\n\n\n\n<p>c \u662f\u4e00\u4e2a(char **)\u7c7b\u578b\u7684\u53d8\u91cf\uff0c\u5b83\u7684\u503c\u662f8092<\/p>\n\n\n\n<p>*c \u662f\u4e00\u4e2a(char*)\u7c7b\u578b\u7684\u53d8\u91cf\uff0c\u5b83\u7684\u503c\u662f7230<\/p>\n\n\n\n<p>**c \u662f\u4e00\u4e2a(char)\u7c7b\u578b\u7684\u53d8\u91cf\uff0c\u5b83\u7684\u503c\u662f&#8217;z&#8217;<\/p>\n\n\n\n<h3>\u7a7a\u6307\u9488void pointers<\/h3>\n\n\n\n<p>\u6307\u9488void \u662f\u4e00\u79cd\u7279\u6b8a\u7c7b\u578b\u7684\u6307\u9488\u3002void \u6307\u9488\u53ef\u4ee5\u6307\u5411\u4efb\u610f\u7c7b\u578b\u7684\u6570\u636e\uff0c\u53ef\u4ee5\u662f\u6574\u6570\uff0c\u6d6e\u70b9\u6570\u751a\u81f3\u5b57\u7b26\u4e32\u3002\u552f\u4e00\u4e2a\u9650\u5236\u662f\u88ab\u6307\u5411\u7684\u6570\u503c\u4e0d\u53ef\u4ee5\u88ab\u76f4\u63a5\u5f15\u7528\uff08\u4e0d\u53ef\u4ee5\u5bf9\u5b83\u4eec\u4f7f\u7528\u5f15\u7528\u661f\u53f7*\uff09\uff0c\u56e0\u4e3a\u5b83\u7684\u957f\u5ea6\u662f\u4e0d\u5b9a\u7684\uff0c\u56e0\u6b64\uff0c\u5fc5\u987b\u4f7f\u7528\u7c7b\u578b\u8f6c\u6362\u64cd\u4f5c\u6216\u8d4b\u503c\u64cd\u4f5c\u6765\u628avoid \u6307\u9488\u6307\u5411\u4e00\u4e2a\u5177\u4f53\u7684\u6570\u636e\u7c7b\u578b\u3002<\/p>\n\n\n\n<p>\u5b83\u7684\u5e94\u7528\u4e4b\u4e00\u662f\u88ab\u7528\u6765\u7ed9\u51fd\u6570\u4f20\u9012\u901a\u7528\u53c2\u6570\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>\/\/ integer increaser<br>#include &lt;iostream.h&gt;<br><br>void increase (void* data, int type) {<br>switch (type) {<br>case sizeof(char) : (*((char*)data))++; break;<br>case sizeof(short): (*((short*)data))++; break;<br>case sizeof(long) : (*((long*)data))++; break;<br>}<br>}<br><br>int main () {<br>char a = 5;<br>short b = 9;<br>long c = 12;<br>increase (&amp;a,sizeof(a));<br>increase (&amp;b,sizeof(b));<br>increase (&amp;c,sizeof(c));<br>cout &lt;&lt; (int) a &lt;&lt; &#8220;, &#8221; &lt;&lt; b &lt;&lt; &#8220;, &#8221; &lt;&lt; c;<br>return 0;<br>}<\/td><td>6, 10, 13<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>sizeof \u662fC++\u7684\u4e00\u4e2a\u64cd\u4f5c\u7b26\uff0c\u7528\u6765\u8fd4\u56de\u5176\u53c2\u6570\u7684\u957f\u5ea6\u5b57\u8282\u6570\u5e38\u91cf\u3002\u4f8b\u5982\uff0csizeof(char) \u8fd4\u56de 1\uff0c\u56e0\u4e3a char \u7c7b\u578b\u662f\uff11\u5b57\u8282\u957f\u6570\u636e\u7c7b\u578b\u3002<\/p>\n\n\n\n<h3>\u51fd\u6570\u6307\u9488Pointers to functions<\/h3>\n\n\n\n<p>C++ \u5141\u8bb8\u5bf9\u6307\u5411\u51fd\u6570\u7684\u6307\u9488\u8fdb\u884c\u64cd\u4f5c\u3002\u5b83\u6700\u5927\u7684\u4f5c\u7528\u662f\u628a\u4e00\u4e2a\u51fd\u6570\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7ed9\u53e6\u5916\u4e00\u4e2a\u51fd\u6570\u3002\u58f0\u660e\u4e00\u4e2a\u51fd\u6570\u6307\u9488\u50cf\u58f0\u660e\u4e00\u4e2a\u51fd\u6570\u539f\u578b\u4e00\u6837\uff0c\u9664\u4e86\u51fd\u6570\u7684\u540d\u5b57\u9700\u8981\u88ab\u62ec\u5728\u62ec\u53f7\u5185\u5e76\u5728\u524d\u9762\u52a0\u661f\u53f7asterisk (*)\u3002\u4f8b\u5982\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td>\/\/ pointer to functions<br>#include &lt;iostream.h&gt;<br><br>int addition (int a, int b) {<br>&nbsp;&nbsp;&nbsp; return (a+b);<br>}<br><br>int subtraction (int a, int b) {<br>&nbsp;&nbsp;&nbsp; return (a-b);<br>}<br><br>int (*minus)(int,int) = subtraction;<br>int operation (int x, int y, int (*functocall)(int,int)) {<br>&nbsp;&nbsp;&nbsp; int g;<br>&nbsp;&nbsp;&nbsp; g = (*functocall)(x,y);<br>&nbsp;&nbsp;&nbsp; return (g);<br>}<br><br>int main () {<br>&nbsp;&nbsp;&nbsp; int m,n;<br>&nbsp;&nbsp;&nbsp; m = operation (7, 5, addition);<br>&nbsp;&nbsp;&nbsp; n = operation (20, m, minus);<br>&nbsp;&nbsp;&nbsp; cout &lt;&lt;n;<br>&nbsp;&nbsp;&nbsp; return 0;<br>}<\/td><td>8<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u4f8b\u5b50\u91cc\uff0c minus \u662f\u4e00\u4e2a\u5168\u5c40\u6307\u9488\uff0c\u6307\u5411\u4e00\u4e2a\u6709\u4e24\u4e2a\u6574\u578b\u53c2\u6570\u7684\u51fd\u6570\uff0c\u5b83\u88ab\u8d4b\u503c\u6307\u5411\u51fd\u6570subtraction\uff0c\u6240\u6709\u8fd9\u4e9b\u7531\u4e00\u884c\u4ee3\u7801\u5b9e\u73b0\uff1a<\/p>\n\n\n\n<p><code>int (* minus)(int,int) = subtraction;<\/code><\/p>\n\n\n\n<p><code>\u8fd9\u91cc\u4f3c\u4e4e\u89e3\u91ca\u7684\u4e0d\u592a\u6e05\u695a\uff0c\u6709\u95ee\u9898\u95ee\u4e3a\u4ec0\u4e48(int int)\u53ea\u6709\u7c7b\u578b\uff0c\u6ca1\u6709\u53c2\u6570\uff0c\u5c31\u518d\u591a\u8bf4\u4e24\u53e5\u3002<br><br>\u8fd9\u91cc int (*minus)(int int)\u5b9e\u9645\u662f\u5728\u5b9a\u4e49\u4e00\u4e2a\u6307\u9488\u53d8\u91cf\uff0c\u8fd9\u4e2a\u6307\u9488\u7684\u540d\u5b57\u53eb\u505aminus\uff0c\u8fd9\u4e2a\u6307\u9488\u7684\u7c7b\u578b\u662f\u6307\u5411\u4e00\u4e2a\u51fd\u6570\uff0c\u51fd\u6570\u7684\u7c7b\u578b\u662f\u6709\u4e24\u4e2a\u6574\u578b\u53c2\u6570\u5e76\u8fd4\u56de\u4e00\u4e2a\u6574\u578b\u503c\u3002<\/code><\/p>\n\n\n\n<p><code>\u6574\u53e5\u8bdd\u201cint (*minus)(int,int) = subtraction;\u201d\u662f\u5b9a\u4e49\u4e86\u8fd9\u6837\u4e00\u4e2a\u6307\u9488\u5e76\u628a\u51fd\u6570subtraction\u7684\u503c\u8d4b\u7ed9\u5b83\uff0c\u4e5f\u5c31\u662f\u8bf4\u6709\u4e86\u8fd9\u4e2a\u5b9a\u4e49\u540eminus\u5c31\u4ee3\u8868\u4e86\u51fd\u6570subtraction\u3002\u56e0\u6b64\u62ec\u53f7\u4e2d\u7684\u4e24\u4e2aint int\u5b9e\u9645\u53ea\u662f\u4e00\u79cd\u53d8\u91cf\u7c7b\u578b\u7684\u58f0\u660e\uff0c\u4e5f\u5c31\u662f\u8bf4\u662f\u4e00\u79cd\u5f62\u5f0f\u53c2\u6570\u800c\u4e0d\u662f\u5b9e\u9645\u53c2\u6570\u3002<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"<p>3.3 \u6307\u9488 \uff08Pointers\uff09 \u6211\u4eec\u5df2\u7ecf\u660e\u767d\u53d8\u91cf\u5176\u5b9e\u662f\u53ef\u4ee5\u7531\u6807\u8bc6\u6765\u5b58\u53d6\u7684\u5185\u5b58\u5355\u5143\u3002\u4f46\u8fd9\u4e9b\u53d8\u91cf\u5b9e\u9645\u4e0a\u662f\u5b58\u50a8\u5728\u5185\u5b58\u4e2d\u5177\u4f53\u7684\u4f4d\u7f6e\u4e0a\u7684\u3002\u5bf9\u6211\u4eec\u7684\u7a0b\u5e8f\u6765\u8bf4\uff0c\u8ba1\u7b97\u673a\u5185\u5b58\u53ea\u662f\u4e00\u4e32\u8fde\u7eed\u7684\u5355\u5b57\u8282\u5355\u5143(1byte cell)\uff0c\u5373\u6700\u5c0f\u6570\u636e\u5355\u4f4d\uff0c\u6bcf\u4e00\u4e2a\u5355\u5143\u6709\u4e00\u4e2a\u552f\u4e00\u5730\u5740\u3002 \u8ba1\u7b97\u673a\u5185\u5b58\u5c31\u597d\u50cf\u57ce\u5e02\u4e2d\u7684\u8857\u9053\u3002\u5728\u4e00\u6761\u8857\u4e0a\uff0c\u6240\u6709\u7684\u623f\u5b50\u88ab\u987a\u5e8f\u7f16\u53f7\uff0c\u6bcf\u6240\u623f\u5b50\u6709\u552f\u4e00\u7f16\u53f7\u3002\u56e0\u6b64\u5982\u679c\u6211\u4eec\u8bf4\u829d\u9ebb\u885727\u53f7\uff0c\u6211\u4eec\u5f88\u5bb9\u6613\u627e\u5230\u5b83\uff0c\u56e0\u4e3a\u53ea\u6709\u4e00\u6240\u623f\u5b50\u4f1a\u662f\u8fd9\u4e2a\u7f16\u53f7\uff0c\u800c\u4e14\u6211\u4eec\u77e5\u9053\u5b83\u4f1a\u572826\u53f7\u548c28\u53f7\u4e4b\u95f4\u3002 \u540c\u623f\u5c4b\u6309\u8857\u9053\u5730\u5740\u7f16\u53f7\u4e00\u6837\uff0c\u64cd\u4f5c\u7cfb\u7edf(operating system)\u4e5f\u6309\u7167\u552f\u4e00\u987a\u5e8f\u7f16\u53f7\u6765\u7ec4\u7ec7\u5185\u5b58\u3002\u56e0\u6b64\uff0c\u5f53\u6211\u4eec\u8bf4\u5185\u5b58\u4e2d\u7684\u4f4d\u7f6e1776\uff0c\u6211\u4eec\u77e5\u9053\u5185\u5b58\u4e2d\u53ea\u6709\u4e00\u4e2a\u4f4d\u7f6e\u662f\u8fd9\u4e2a\u5730\u5740\uff0c\u800c\u4e14\u5b83\u5728\u5730\u57401775\u548c1777\u4e4b\u95f4\u3002 \u5730\u5740\u64cd\u4f5c\u7b26\/\u53bb\u5f15\u64cd\u4f5c\u7b26 Address\/dereference operator (&amp;) \u5f53\u6211\u4eec\u58f0\u660e\u4e00\u4e2a\u53d8\u91cf\u7684\u540c\u65f6\uff0c\u5b83\u5fc5\u987b\u88ab\u5b58\u50a8\u5230\u5185\u5b58\u4e2d\u4e00\u4e2a\u5177\u4f53\u7684\u5355\u5143\u4e2d\u3002\u901a\u5e38\u6211\u4eec\u5e76\u4e0d\u4f1a\u6307\u5b9a\u53d8\u91cf\u88ab\u5b58\u50a8\u5230\u54ea\u4e2a\u5177\u4f53\u7684\u5355\u5143\u4e2d\u2014\u5e78\u4e8f\u8fd9\u901a\u5e38\u662f\u7531\u7f16\u8bd1\u5668\u548c\u64cd\u4f5c\u7cfb\u7edf\u81ea\u52a8\u5b8c\u6210\u7684\uff0c\u4f46\u4e00\u65e6\u64cd\u4f5c\u7cfb\u7edf\u6307\u5b9a\u4e86\u4e00\u4e2a\u5730\u5740\uff0c\u6709\u4e9b\u65f6\u5019\u6211\u4eec\u53ef\u80fd\u4f1a\u60f3\u77e5\u9053\u53d8\u91cf\u88ab\u5b58\u50a8\u5728\u54ea\u91cc\u4e86\u3002 \u8fd9\u53ef\u4ee5\u901a\u8fc7\u5728\u53d8\u91cf\u6807\u8bc6\u524d\u9762\u52a0\u4e0e\u7b26\u53f7ampersand sign (&amp;)\u6765\u5b9e\u73b0\uff0c\u5b83\u8868\u793a&#8221;&#8230;\u7684\u5730\u5740&#8221; (&#8220;address of&#8221;)\uff0c\u56e0\u6b64\u79f0\u4e3a\u5730\u5740\u64cd\u4f5c\u7b26(adress operator)\uff0c\u53c8\u79f0\u53bb\u5f15\u64cd\u4f5c\u7b26(dereference operator)\u3002\u4f8b\u5982\uff1a ted = &amp;andy; \u5c06\u53d8\u91cfandy\u7684\u5730\u5740\u8d4b\u7ed9\u53d8\u91cfted\uff0c\u56e0\u4e3a\u5f53\u5728\u53d8\u91cf\u540d\u79f0andy \u524d\u9762\u52a0ampersand (&amp;) \u7b26\u53f7\uff0c\u6211\u4eec\u6307\u7684\u5c06\u4e0d\u518d\u662f\u8be5\u53d8\u91cf\u7684\u5185\u5bb9\uff0c\u800c\u662f\u5b83\u5728\u5185\u5b58\u4e2d\u7684\u5730\u5740\u3002 \u5047\u8bbeandy \u88ab\u653e\u5728\u4e86\u5185\u5b58\u4e2d\u5730\u57401776\u7684\u5355\u5143\u4e2d\uff0c\u7136\u540e\u6211\u4eec\u6709\u4e0b\u5217\u4ee3\u7801\uff1aandy = 25;fred = andy;ted = &amp;andy; \u5176\u7ed3\u679c\u663e\u793a\u5728\u4e0b\u9762\u7684\u56fe\u7247\u4e2d\uff1a \u6211\u4eec\u5c06\u53d8\u91cfandy \u7684\u503c\u8d4b\u7ed9\u53d8\u91cffred\uff0c\u8fd9\u4e0e\u4ee5\u524d\u6211\u4eec\u770b\u5230\u5f88\u591a\u4f8b\u5b50\u90fd\u76f8\u540c\uff0c\u4f46\u5bf9\u4e8eted\uff0c\u6211\u4eec\u628a\u64cd\u4f5c\u7cfb\u7edf\u5b58\u50a8andy\u7684\u5185\u5b58\u5730\u5740\u8d4b\u7ed9\u5b83\uff0c\u6211\u4eec\u60f3\u50cf\u8be5\u5730\u5740\u4e3a1776 (\u5b83\u53ef\u4ee5\u662f\u4efb\u4f55\u5730\u5740\uff0c\u8fd9\u91cc\u53ea\u662f\u4e00\u4e2a\u5047\u8bbe\u7684\u5730\u5740)\uff0c\u539f\u56e0\u662f\u5f53\u7ed9ted \u8d4b\u503c\u7684\u65f6\u5019\uff0c\u6211\u4eec\u5728andy \u524d\u9762\u52a0\u4e86ampersand (&amp;) \u7b26\u53f7\u3002 \u5b58\u50a8\u5176\u5b83\u53d8\u91cf\u5730\u5740\u7684\u53d8\u91cf(\u5982\u4e0a\u9762\u4f8b\u5b50\u4e2d\u7684ted )\uff0c\u6211\u4eec\u79f0\u4e4b\u4e3a\u6307\u9488(pointer)\u3002\u5728C++ \u4e2d\uff0c\u6307\u9488pointers \u6709\u5176\u7279\u5b9a\u7684\u4f18\u70b9\uff0c\u56e0\u6b64\u7ecf\u5e38\u88ab\u4f7f\u7528\u3002\u5728\u540e\u9762\u6211\u4eec\u5c06\u4f1a\u770b\u5230\u8fd9\u79cd\u53d8\u91cf\u5982\u4f55\u88ab\u58f0\u660e\u3002 \u5f15\u7528\u64cd\u4f5c\u7b26Reference operator (*) \u4f7f\u7528\u6307\u9488\u7684\u65f6\u5019\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u5728\u6307\u9488\u6807\u8bc6\u7684\u524d\u9762\u52a0\u661f\u53f7asterisk (*)\u6765\u5b58\u50a8\u8be5\u6307\u9488\u6307\u5411\u7684\u53d8\u91cf\u6240\u5b58\u50a8\u7684\u6570\u503c\uff0c\u5b83\u53ef\u4ee5\u88ab\u7ffb\u8bd1\u4e3a\u201c\u6240\u6307\u5411\u7684\u6570\u503c\u201d\uff08&#8221;value pointed by&#8221;\uff09\u3002\u56e0\u6b64\uff0c\u4ecd\u7528\u524d\u9762\u4f8b\u5b50\u4e2d\u7684\u6570\u503c\uff0c\u5982\u679c\u6211\u4eec\u5199\uff1a beth [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":335,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/pages\/343"}],"collection":[{"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/comments?post=343"}],"version-history":[{"count":1,"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/pages\/343\/revisions"}],"predecessor-version":[{"id":344,"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/pages\/343\/revisions\/344"}],"up":[{"embeddable":true,"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/pages\/335"}],"wp:attachment":[{"href":"https:\/\/www.prglab.com\/blog\/wp-json\/wp\/v2\/media?parent=343"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}