{"id":16,"date":"2016-04-02T15:12:06","date_gmt":"2016-04-02T07:12:06","guid":{"rendered":"http:\/\/www.91tfboys.com\/?p=16"},"modified":"2017-01-03T21:27:35","modified_gmt":"2017-01-03T13:27:35","slug":"%e7%bb%93%e6%9e%84%e4%bd%93%e5%a4%a7%e5%b0%8f%e7%9a%84%e8%ae%a1%e7%ae%97%e6%97%a0%e8%af%b4%e6%98%8e%e7%9a%84%e9%bb%98%e8%ae%a432%e4%bd%8d%e6%9c%ba","status":"publish","type":"post","link":"https:\/\/www.91tfboys.com\/?p=16","title":{"rendered":"\u7ed3\u6784\u4f53\u5927\u5c0f\u7684\u8ba1\u7b97(\u65e0\u8bf4\u660e\u7684\u9ed8\u8ba432\u4f4d\u673a)"},"content":{"rendered":"

\uff08\u539f\u6587\u94fe\u63a5http:\/\/www.jiancool.com\/article\/3076377672\/<\/a>\uff09<\/p>\n

\u5173\u4e8e\u7ed3\u6784\u4f53\u5185\u5b58\u5bf9\u9f50
\n\u201c\u5185\u5b58\u5bf9\u9f50\u201d\u5e94\u8be5\u662f\u7f16\u8bd1\u5668\u7684\u201c\u7ba1\u8f96\u8303\u56f4\u201d\u3002\u7f16\u8bd1\u5668\u4e3a\u7a0b\u5e8f\u4e2d\u7684\u6bcf\u4e2a\u201c\u6570\u636e\u5355\u5143\u201d\u5b89\u6392\u5728\u9002\u5f53\u7684\u4f4d\u7f6e\u4e0a\u3002\u4f46\u662fC\u8bed\u8a00\u7684\u4e00\u4e2a\u7279\u70b9\u5c31\u662f\u592a\u7075\u6d3b\uff0c\u592a\u5f3a\u5927\uff0c\u5b83\u5141\u8bb8\u4f60\u5e72\u9884\u201c\u5185\u5b58\u5bf9\u9f50\u201d\u3002\u5982\u679c\u4f60\u60f3\u4e86\u89e3\u66f4\u52a0\u5e95\u5c42\u7684\u79d8\u5bc6\uff0c\u201c\u5185\u5b58\u5bf9\u9f50\u201d\u5bf9\u4f60\u5c31\u4e0d\u5e94\u8be5\u518d\u900f\u660e\u4e86\u3002
\n\u4e00\u3001\u5185\u5b58\u5bf9\u9f50\u7684\u539f\u56e0
\n\u5927\u90e8\u5206\u7684\u53c2\u8003\u8d44\u6599\u90fd\u662f\u5982\u662f\u8bf4\u7684\uff1a
\n1\u3001\u5e73\u53f0\u539f\u56e0(\u79fb\u690d\u539f\u56e0)\uff1a\u4e0d\u662f\u6240\u6709\u7684\u786c\u4ef6\u5e73\u53f0\u90fd\u80fd\u8bbf\u95ee\u4efb\u610f\u5730\u5740\u4e0a\u7684\u4efb\u610f\u6570\u636e\u7684\uff1b\u67d0\u4e9b\u786c\u4ef6\u5e73\u53f0\u53ea\u80fd\u5728\u67d0\u4e9b\u5730\u5740\u5904\u53d6\u67d0\u4e9b\u7279\u5b9a\u7c7b\u578b\u7684\u6570\u636e\uff0c\u5426\u5219\u629b\u51fa\u786c\u4ef6\u5f02\u5e38\u3002
\n2\u3001\u6027\u80fd\u539f\u56e0\uff1a\u6570\u636e\u7ed3\u6784(\u5c24\u5176\u662f\u6808)\u5e94\u8be5\u5c3d\u53ef\u80fd\u5730\u5728\u81ea\u7136\u8fb9\u754c\u4e0a\u5bf9\u9f50\u3002\u539f\u56e0\u5728\u4e8e\uff0c\u4e3a\u4e86\u8bbf\u95ee\u672a\u5bf9\u9f50\u7684\u5185\u5b58\uff0c\u5904\u7406\u5668\u9700\u8981\u4f5c\u4e24\u6b21\u5185\u5b58\u8bbf\u95ee\uff1b\u800c\u5bf9\u9f50\u7684\u5185\u5b58\u8bbf\u95ee\u4ec5\u9700\u8981\u4e00\u6b21\u8bbf\u95ee\u3002<\/p>\n

\u4e8c\u3001\u5bf9\u9f50\u89c4\u5219
\n\u6bcf\u4e2a\u7279\u5b9a\u5e73\u53f0\u4e0a\u7684\u7f16\u8bd1\u5668\u90fd\u6709\u81ea\u5df1\u7684\u9ed8\u8ba4\u201c\u5bf9\u9f50\u7cfb\u6570\u201d(\u4e5f\u53eb\u5bf9\u9f50\u6a21\u6570)\u3002\u7a0b\u5e8f\u5458\u53ef\u4ee5\u901a\u8fc7\u9884\u7f16\u8bd1\u547d\u4ee4#pragma pack(n)<\/span>\uff0cn=1,2,4,8,16\u6765\u6539\u53d8\u8fd9\u4e00\u7cfb\u6570\uff0c\u5176\u4e2d\u7684n\u5c31\u662f\u4f60\u8981\u6307\u5b9a\u7684\u201c\u5bf9\u9f50\u7cfb\u6570\u201d\u3002 \u5bf9\u9f50\u6b65\u9aa4\uff1a
\n1\u3001\u6570\u636e\u6210\u5458\u5bf9\u9f50\u89c4\u5219\uff1a\u7ed3\u6784(struct)(\u6216\u8054\u5408(union))\u7684\u6570\u636e\u6210\u5458\uff0c\u7b2c\u4e00\u4e2a\u6570\u636e\u6210\u5458\u653e\u5728offset\u4e3a0\u7684\u5730\u65b9\uff0c\u4ee5\u540e\u6bcf\u4e2a\u6570\u636e\u6210\u5458\u7684\u5bf9\u9f50\u6309\u7167#pragma pack\u6307\u5b9a\u7684\u6570\u503c\u548c\u8fd9\u4e2a\u6570\u636e\u6210\u5458\u81ea\u8eab\u957f\u5ea6\u4e2d\uff0c\u6bd4\u8f83\u5c0f\u7684\u90a3\u4e2a\u8fdb\u884c\u3002<\/p>\n

2\u3001\u7ed3\u6784(\u6216\u8054\u5408)\u7684\u6574\u4f53\u5bf9\u9f50\u89c4\u5219\uff1a\u5728\u6570\u636e\u6210\u5458\u5b8c\u6210\u5404\u81ea\u5bf9\u9f50\u4e4b\u540e\uff0c\u7ed3\u6784(\u6216\u8054\u5408)\u672c\u8eab\u4e5f\u8981\u8fdb\u884c\u5bf9\u9f50\uff0c\u5bf9\u9f50\u5c06\u6309\u7167#pragma pack\u6307\u5b9a\u7684\u6570\u503c\u548c\u7ed3\u6784(\u6216\u8054\u5408)\u6700\u5927\u6570\u636e\u6210\u5458\u957f\u5ea6\u4e2d\uff0c\u6bd4\u8f83\u5c0f\u7684\u90a3\u4e2a\u8fdb\u884c\u3002<\/p>\n

3\u3001\u7ed3\u54081\u30012\u9897\u63a8\u65ad\uff1a\u5f53#pragma pack\u7684n\u503c\u7b49\u4e8e\u6216\u8d85\u8fc7\u6240\u6709\u6570\u636e\u6210\u5458\u957f\u5ea6\u7684\u65f6\u5019\uff0c\u8fd9\u4e2an\u503c\u7684\u5927\u5c0f\u5c06\u4e0d\u4ea7\u751f\u4efb\u4f55\u6548\u679c\u3002
\n\u5907\u6ce8\uff1a\u6570\u7ec4\u6210\u5458\u6309\u957f\u5ea6\u6309\u6570\u7ec4\u7c7b\u578b\u957f\u5ea6\u8ba1\u7b97\uff0c\u5982char t[9],\u5728\u7b2c1\u6b65\u4e2d\u6570\u636e\u81ea\u8eab\u957f\u5ea6\u63091\u7b97\uff0c\u7d2f\u52a0\u7ed3\u6784\u4f53\u65f6\u957f\u5ea6\u4e3a9;\u7b2c2\u6b65\u4e2d\uff0c\u627e\u6700\u5927\u6570\u636e\u957f\u5ea6\u65f6\uff0c\u5982\u679c\u7ed3\u6784\u4f53T\u6709\u590d\u6742\u7c7b\u578b\u6210\u5458A\u7684\uff0c\u8be5A\u6210\u5458\u7684\u957f\u5ea6\u4e3a\u8be5\u590d\u6742\u7c7b\u578b\u6210\u5458A\u7684\u6700\u5927\u6210\u5458\u957f\u5ea6\u3002<\/p>\n

 <\/p>\n

\u4e00\u3002\u7ed3\u6784\u4f53\u5927\u5c0f\u8ba1\u7b97\u57fa\u7840<\/h1>\n

\u57fa\u7840\u4e00<\/h2>\n

\u5148\u4ecb\u7ecd\u4e00\u4e2a\u76f8\u5173\u7684\u6982\u5ff5\u2014\u2014\u504f\u79fb\u91cf\u3002\u504f\u79fb\u91cf\u6307\u7684\u662f\u7ed3\u6784\u4f53\u53d8\u91cf\u4e2d\u6210\u5458\u7684\u5730\u5740\u548c\u7ed3\u6784\u4f53\u53d8\u91cf\u5730\u5740\u7684\u5dee\u3002\u7ed3\u6784\u4f53\u5927\u5c0f\u7b49\u4e8e\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u5927\u5c0f\u3002\u7531\u4e8e\u5b58\u50a8\u53d8\u91cf\u65f6\u5730\u5740\u5bf9\u9f50\u7684\u8981\u6c42\uff0c\u7f16\u8bd1\u5668\u5728\u7f16\u8bd1\u7a0b\u5e8f\u65f6\u4f1a\u9075\u5faa\u4e24\u6761\u539f\u5219\uff1a<\/p>\n

\u4e00\u3001\u7ed3\u6784\u4f53\u53d8\u91cf\u4e2d\u6210\u5458\u7684\u504f\u79fb\u91cf\u5fc5\u987b\u662f\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff080\u88ab\u8ba4\u4e3a\u662f\u4efb\u4f55\u6570\u7684\u6574\u6570\u500d\uff09<\/p>\n

\u4e8c\u3001\u7ed3\u6784\u4f53\u5927\u5c0f\u5fc5\u987b\u662f\u6240\u6709\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002<\/p>\n

\u8fd9\u662f\u4e00\u79cd\u8bf4\u6cd5\uff0c\u8fd8\u6709\u4e00\u79cd\u8bf4\u6cd5\uff1a<\/p>\n

\u7ed3\u6784\u4f53\u9ed8\u8ba4\u7684\u5b57\u8282\u5bf9\u9f50\u4e00\u822c\u6ee1\u8db3\u4e09\u4e2a\u51c6\u5219\uff1a
\n1) \u7ed3\u6784\u4f53\u53d8\u91cf\u7684\u9996\u5730\u5740\u80fd\u591f\u88ab\u5176\u6700\u5bbd\u57fa\u672c\u7c7b\u578b\u6210\u5458\u7684\u5927\u5c0f\u6240\u6574\u9664\uff1b
\n2) \u7ed3\u6784\u4f53\u6bcf\u4e2a\u6210\u5458\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740\u7684\u504f\u79fb\u91cf\uff08offset\uff09\u90fd\u662f\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff0c
\n\u5982\u6709\u9700\u8981\u7f16\u8bd1\u5668\u4f1a\u5728\u6210\u5458\u4e4b\u95f4\u52a0\u4e0a\u586b\u5145\u5b57\u8282\uff08internal adding\uff09\uff1b
\n3) \u7ed3\u6784\u4f53\u7684\u603b\u5927\u5c0f\u4e3a\u7ed3\u6784\u4f53\u6700\u5bbd\u57fa\u672c\u7c7b\u578b\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff0c\u5982\u6709\u9700\u8981\u7f16\u8bd1\u5668\u4f1a\u5728\u6700\u672b
\n\u4e00\u4e2a\u6210\u5458\u4e4b\u540e\u52a0\u4e0a\u586b\u5145\u5b57\u8282\u3002<\/p>\n

\u6211\u81ea\u5df1\u5199\u4e86\u4e09\u4e2a\u7ed3\u6784\u4f53\u6d4b\u8bd5\u4e86\u4e00\u4e0b\uff0c\u4ee3\u7801\u5982\u4e0b\uff1a
\n\"\"
\n\u8f93\u51fa\u7ed3\u679c\u662f\uff1a
\n12
\n8
\n20<\/p>\n

\u5148\u770b\u7b2c\u4e00\u4e2a\u7ed3\u6784\u4f53\uff0c\u7b2c\u4e00\u4e2a\u6210\u5458a\u7684\u504f\u79fb\u91cf\u4e3a0\u3002\u7b2c\u4e8c\u4e2a\u6210\u5458b\u7684\u504f\u79fb\u91cf\u662f\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u5927\u5c0f\uff080+4\uff09,\u5176\u503c\u4e3a4\uff1b\u7b2c\u4e09\u4e2a\u6210\u5458c\u7684\u504f\u79fb \u91cf\u662f\u7b2c\u4e8c\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u7b2c\u4e8c\u4e2a\u6210\u5458\u7684\u5927\u5c0f\uff084+1\uff09,\u5176\u503c\u4e3a5\u3002\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u524d\u4e24\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u90fd\u6ee1\u8db3\u8981\u6c42\uff0c\u4f46\u7b2c\u4e09\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u4e3a5\uff0c\u5e76\u4e0d\u662f\u81ea\u8eab (int)\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002\u7f16\u8bd1\u5668\u5728\u5904\u7406\u65f6\u4f1a\u5728\u7b2c\u4e8c\u4e2a\u6210\u5458\u540e\u9762\u8865\u4e0a3\u4e2a\u7a7a\u5b57\u8282\uff0c\u4f7f\u5f97\u7b2c\u4e09\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u53d8\u62108\u3002\u7ed3\u6784\u4f53\u5927\u5c0f\u7b49\u4e8e\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u6700\u540e \u4e00\u4e2a\u6210\u5458\u7684\u5927\u5c0f\u3002\u504f\u79fb\u91cf8\u52a0\u4e0a\u6700\u540e\u4e00\u4e2a\u6210\u5458c\u81ea\u8eab\u7684\u5927\u5c0f\uff0c\u5373\u4e3a9\uff0c9\u4e0d\u80fd\u88ab\u6700\u5bbd\u57fa\u672c\u7c7b\u578b\u6210\u5458\u5927\u5c0f\u6574\u9664\uff0c\u6240\u4ee5\u8fd9\u91cc\u7f16\u8bd1\u5668\u4f1a\u5728\u6700\u540e\u8865\u9f503\u4e2a\u5b57\u8282\uff0c\u5f97\u51fa12\u3002
\n\u81f3\u4e8e\u7b2c\u4e8c\u4e2a\u7ed3\u6784\u4f53\uff0c\u5927\u5c0f\u7b49\u4e8e\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u5176\u5927\u5c0f\uff0c\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u8ba1\u7b97\u51fa\u6765\u7684\u5927\u5c0f\u4e3a8\uff0c\u6ee1\u8db3\u8981\u6c42\u3002
\n\u6309\u7167\u4e0a\u8ff0\u7684\u8ba1\u7b97\u89c4\u5219\uff0c\u7ed3\u6784\u4f53\u4e00\u548c\u7ed3\u6784\u4f53\u4e8c\u90fd\u53ef\u4ee5\u8ba1\u7b97\u51fa\u4e0e\u8f93\u51fa\u4e00\u81f4\u7684\u7ed3\u679c\uff0c\u53ef\u662f\u7ed3\u6784\u4f53\u4e09\u6709\u70b9\u4e0d\u660e\u767d\u3002\/\/\u572832\u4f4d\u673a\u5668\u4e2d\uff0cdouble\u578b\u8981\u62c6\u5206\u6210\u4e24\u4e2aint\u578b\uff0c\u5982\u4e0b\uff1a<\/p>\n

\u504f\u79fb\u91cf \u586b\u5145\u5b57\u8282 \u6210\u5458\u81ea\u8eab\u5927\u5c0f
\n0 4
\n4 1
\n5 1 2
\n8 4
\n12 4
\n16 4
\n20
\n\u6700\u7ec8\u7ed3\u679c\u662f20\uff0c\u572864\u4f4d\u673a\u5668\u4e2ddouble\u5c31\u63098\u5b57\u8282\u7b97<\/p>\n

\u57fa\u7840\u4e8c<\/h2>\n

\u7ed3<\/span>\u6784\u4f53\u4e2d\u7684\u6210\u5458\u53ef\u4ee5\u662f\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b\uff0c\u6210\u5458\u6309\u7167\u5b9a\u4e49\u65f6\u7684\u987a\u5e8f\u4f9d\u6b21\u5b58\u50a8\u5728\u8fde\u7eed\u7684\u5185\u5b58\u7a7a\u95f4\u3002\u548c\u6570\u7ec4\u4e0d\u4e00\u6837\u7684\u662f\uff0c\u7ed3\u6784\u4f53\u7684\u5927\u5c0f\u4e0d\u662f\u6240\u6709\u6210\u5458\u5927\u5c0f\u7b80\u5355\u7684\u76f8\u52a0\uff0c\u9700\u8981\u8003\u8651\u5230\u7cfb\u7edf\u5728\u5b58\u50a8\u7ed3\u6784\u4f53\u53d8\u91cf\u65f6\u7684\u5730\u5740\u5bf9\u9f50\u95ee\u9898\u3002\u770b\u4e0b\u9762\u8fd9\u6837\u7684\u4e00\u4e2a\u7ed3\u6784\u4f53\uff1a <\/span>
\n\u3000\u3000struct stu1 <\/span>
\n\u3000\u3000{ <\/span>
\n\u3000 \u3000int i; <\/span>
\n \u3000\u3000char c; <\/span>
\n\u3000 \u3000int j; <\/span>
\n\u3000\u3000}\uff1b <\/span>
\n\u3000\u3000\u5148\u4ecb\u7ecd\u4e00\u4e2a\u76f8\u5173\u7684\u6982\u5ff5\u2014\u2014\u504f\u79fb\u91cf\u3002\u504f\u79fb\u91cf\u6307 \u7684\u662f\u7ed3\u6784\u4f53\u53d8\u91cf\u4e2d\u6210\u5458\u7684\u5730\u5740\u548c\u7ed3\u6784\u4f53\u53d8\u91cf\u5730\u5740\u7684\u5dee\u3002\u7ed3\u6784\u4f53\u5927\u5c0f\u7b49\u4e8e\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u5927\u5c0f\u3002\u663e\u7136\uff0c\u7ed3\u6784\u4f53\u53d8\u91cf\u4e2d\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u5730\u5740\u5c31\u662f \u7ed3\u6784\u4f53\u53d8\u91cf\u7684\u9996\u5730\u5740\u3002\u56e0\u6b64\uff0c\u7b2c\u4e00\u4e2a\u6210\u5458i\u7684\u504f\u79fb\u91cf\u4e3a0\u3002\u7b2c\u4e8c\u4e2a\u6210\u5458c\u7684\u504f\u79fb\u91cf\u662f\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u5927\u5c0f\uff080+4\uff09,\u5176\u503c\u4e3a4\uff1b\u7b2c\u4e09\u4e2a\u6210\u5458 j\u7684\u504f\u79fb\u91cf\u662f\u7b2c\u4e8c\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u7b2c\u4e8c\u4e2a\u6210\u5458\u7684\u5927\u5c0f\uff084+1\uff09,\u5176\u503c\u4e3a5\u3002 <\/span>
\n\u3000\u3000\u5b9e\u9645\u4e0a\uff0c\u7531\u4e8e\u5b58\u50a8\u53d8\u91cf\u65f6\u5730\u5740\u5bf9\u9f50\u7684\u8981\u6c42\uff0c\u7f16\u8bd1\u5668\u5728\u7f16\u8bd1\u7a0b\u5e8f\u65f6\u4f1a\u9075\u5faa\u4e24\u6761\u539f\u5219\uff1a\u4e00\u3001\u7ed3\u6784\u4f53\u53d8\u91cf\u4e2d\u6210\u5458\u7684\u504f\u79fb\u91cf\u5fc5\u987b\u662f\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff080\u88ab\u8ba4\u4e3a\u662f\u4efb\u4f55\u6570\u7684\u6574\u6570\u500d\uff09 \u4e8c\u3001\u7ed3\u6784\u4f53\u5927\u5c0f\u5fc5\u987b\u662f\u6240\u6709\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002 <\/span>
\n\u3000\u3000\u5bf9\u7167\u7b2c\u4e00\u6761\uff0c\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u524d\u4e24\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u90fd\u6ee1\u8db3\u8981\u6c42\uff0c\u4f46\u7b2c\u4e09\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u4e3a5\uff0c\u5e76\u4e0d\u662f\u81ea\u8eab(int)\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002\u7f16\u8bd1\u5668\u5728\u5904\u7406\u65f6\u4f1a\u5728\u7b2c\u4e8c\u4e2a\u6210\u5458\u540e\u9762\u8865\u4e0a3\u4e2a\u7a7a\u5b57\u8282\uff0c\u4f7f\u5f97\u7b2c\u4e09\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u53d8\u62108\u3002 <\/span>
\n\u3000\u3000\u5bf9\u7167\u7b2c\u4e8c\u6761\uff0c\u7ed3\u6784\u4f53\u5927\u5c0f\u7b49\u4e8e\u6700\u540e\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u52a0\u4e0a\u5176\u5927\u5c0f\uff0c\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u8ba1\u7b97\u51fa\u6765\u7684\u5927\u5c0f\u4e3a12\uff0c\u6ee1\u8db3\u8981\u6c42\u3002 <\/span>
\n\u3000\u3000\u518d\u770b\u4e00\u4e2a\u6ee1\u8db3\u7b2c\u4e00\u6761\uff0c\u4e0d\u6ee1\u8db3\u7b2c\u4e8c\u6761\u7684\u60c5\u51b5 <\/span>
\n\u3000\u3000struct stu2 <\/span>
\n\u3000\u3000{ <\/span>
\n\u3000 \u3000int k; <\/span>
\n \u3000\u3000short t; <\/span>
\n\u3000\u3000}\uff1b <\/span>
\n\u3000\u3000\u6210\u5458k\u7684\u504f\u79fb\u91cf\u4e3a0\uff1b\u6210\u5458t\u7684\u504f\u79fb\u91cf\u4e3a4\uff0c \u90fd\u4e0d\u9700\u8981\u8c03\u6574\u3002\u4f46\u8ba1\u7b97\u51fa\u6765\u7684\u5927\u5c0f\u4e3a6\uff0c\u663e\u7136\u4e0d\u662f\u6210\u5458k\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002\u56e0\u6b64\uff0c\u7f16\u8bd1\u5668\u4f1a\u5728\u6210\u5458t\u540e\u9762\u8865\u4e0a2\u4e2a\u5b57\u8282\uff0c\u4f7f\u5f97\u7ed3\u6784\u4f53\u7684\u5927\u5c0f\u53d8\u62108\u4ece\u800c\u6ee1\u8db3\u7b2c\u4e8c\u4e2a\u8981 \u6c42\u3002\u7531\u6b64\u53ef\u89c1\uff0c\u5927\u5bb6\u5728\u5b9a\u4e49\u7ed3\u6784\u4f53\u7c7b\u578b\u65f6\u9700\u8981\u8003\u8651\u5230\u5b57\u8282\u5bf9\u9f50\u7684\u60c5\u51b5\uff0c\u4e0d\u540c\u7684\u987a\u5e8f\u4f1a\u5f71\u54cd\u5230\u7ed3\u6784\u4f53\u7684\u5927\u5c0f\u3002\u5bf9\u6bd4\u4e0b\u9762\u4e24\u79cd\u5b9a\u4e49\u987a\u5e8f <\/span>
\n\u3000\u3000struct stu3 <\/span>
\n\u3000\u3000{ <\/span>
\n \u3000\u3000char c1;\/\/\u504f\u79fb\u91cf\u4e3a0\u7b26\u5408\u8981\u6c42 <\/span>
\n \u3000\u3000int i;\/\/\u504f\u79fb\u91cf\u4e3a1\uff0c <\/span>\u7ed3\u6784\u4f53\u53d8\u91cf\u4e2d\u6210\u5458\u7684\u504f\u79fb\u91cf\u5fc5\u987b\u662f\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff080\u88ab\u8ba4\u4e3a\u662f\u4efb\u4f55\u6570\u7684\u6574\u6570\u500d\uff09\uff0c\u6545\u504f\u79fb\u91cf\u5e94\u4e3a4 <\/span>
\n \u3000\u3000char c2;\/\/\u504f\u79fb\u91cf\u4e3a8\uff08\u504f\u79fb\u91cf4+int\u59272\u5c0f4\uff09\uff0c\u7b26\u5408\u8981\u6c42 <\/span>
\n\u3000\u3000} <\/span>
\n \u7b97\u51fasizeof( <\/span>stu3 <\/span>)=1+8=9\uff0c\u4f469\u4e0d\u662fint\u7684\u6574\u6570\u500d\u6545\u6700\u7ec8\u5927\u5c0f\u4e3a12
\n<\/span>
\n\u3000\u3000struct stu4 <\/span>
\n\u3000\u3000{ <\/span>
\n \u3000\u3000char c1; <\/span>\/\/\u504f\u79fb\u91cf\u4e3a0\u7b26\u5408\u8981\u6c42 <\/span>
\n \u3000\u3000char c2;\/\/ <\/span>\/\/\u504f\u79fb\u91cf\u4e3a1\u7b26\u5408\u8981\u6c42 <\/span>
\n \u3000\u3000int i; <\/span>\/\/\u504f\u79fb\u91cf\u4e3a2\u4e0d\u7b26\u5408\u8981\u6c42\u6545\u504f\u79fb\u91cf\u4e3a4 <\/span>
\n\u3000\u3000} <\/span>
\n\u7b97\u51fasizeof( <\/span>stu4 <\/span>)=4+4=8\uff0c8\u662fint\u7684\u6574\u6570\u500d\u6545\u6700\u7ec8\u5927\u5c0f\u4e3a8 <\/span><\/p>\n

\u5982\u679c\u7ed3\u6784\u4f53\u4e2d\u7684\u6210\u5458\u53c8\u662f\u53e6\u5916\u4e00\u79cd\u7ed3\u6784\u4f53\u7c7b\u578b\u65f6\u5e94\u8be5\u600e\u4e48\u8ba1\u7b97\u5462\uff1f\u53ea\u9700\u628a\u5176\u5c55\u5f00\u5373\u53ef\u3002\u4f46\u6709\u4e00\u70b9\u9700\u8981\u6ce8\u610f\uff0c\u5c55\u5f00\u540e\u7684\u7ed3\u6784\u4f53\u7684\u7b2c\u4e00\u4e2a\u6210\u5458\u7684\u504f\u79fb\u91cf\u5e94\u5f53\u662f\u88ab\u5c55\u5f00\u7684\u7ed3\u6784\u4f53\u4e2d\u6700\u5927\u7684\u6210\u5458\u7684\u6574\u6570\u500d\u3002\u770b\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a <\/span>
\n\u3000\u3000struct stu5 <\/span>
\n\u3000\u3000{ <\/span>
\n\u3000 \u3000short i; <\/span>
\n\u3000 \u3000struct <\/span>
\n\u3000 \u3000{ <\/span>
\n\u3000 \u3000char c; <\/span>
\n \u3000\u3000int j; <\/span>
\n\u3000 \u3000} ss; <\/span>
\n\u3000 \u3000int k; <\/span>
\n\u3000\u3000} <\/span>
\n\u3000\u3000\u7ed3\u6784\u4f53stu5\u7684\u6210\u5458ss.c\u7684\u504f\u79fb\u91cf\u5e94\u8be5\u662f4\uff0c\u800c\u4e0d\u662f 2\u3002\u6574\u4e2a\u7ed3\u6784\u4f53\u5927\u5c0f\u5e94\u8be5\u662f16\u3002 <\/span><\/p>\n

\u4e8c\u3002\u7ed3\u6784\u4f53\u5927\u5c0f\u8ba1\u7b97\u6df1\u5165\uff08\u7ed3\u6784\u4f53\u5d4c\u5957\uff0c\u6570\u7ec4\uff0c\u5171\u7528\u4f53\uff09<\/h1>\n

\u5bf9\u4e8e32\u4f4d\u673a\u5668\uff0cdouble\u4f1a\u62c6\u5206\u6210\u4e24\u4e2aint\u8fdb\u884c\u8ba1\u7b97\u3002<\/p>\n

\u5bf9\u4e8e\u7ed3\u6784\u4f53
\n\u9996\u5148\u7406\u89e3\u5b57\u8282\u5bf9\u9f50\u673a\u5236\uff1a
\n\uff081\uff09\u7ed3\u6784\u4f53\u53d8\u91cf\u7684\u9996\u5730\u5740\u80fd\u591f\u88ab\u5176\u6700\u5bbd\u57fa\u672c\u7c7b\u578b\u6210\u5458\u5927\u5c0f\u6240\u6574\u9664\u3002
\n\uff082\uff09\u7ed3\u6784\u4f53\u6bcf\u4e2a\u6210\u5458\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740\u7684\u504f\u79fb\u91cf\uff08offset\uff09\u90fd\u662f\u8be5\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff0c\u5982\u6709\u9700\u8981\uff0c\u7f16\u8bd1\u5668\u4f1a\u5728\u6210\u5458\u4e4b\u95f4\u52a0\u4e0a\u4e2d\u95f4\u586b\u5145\u5b57\u8282\u3002
\n\uff083\uff09\u7ed3\u6784\u4f53\u603b\u5927\u5c0f\u4e3a\u7ed3\u6784\u4f53\u6700\u5bbd\u57fa\u672c\u7c7b\u578b\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\uff0c\u5982\u6709\u9700\u8981\uff0c\u7f16\u8bd1\u5668\u4f1a\u5728\u6700\u672b\u4e00\u4e2a\u6210\u5458\u4e4b\u540e\u52a0\u4e0a\u672b\u5c3e\u586b\u5145\u5b57\u8282\u3002
\n\u7b2c\uff082\uff09\u3001\uff083\uff09\u6761\u51c6\u5219\u51b3\u5b9a\u4e86\u7ed3\u6784\u4f53\u53d8\u91cf\u5360\u636e\u5185\u5b58\u7a7a\u95f4\u7684\u5927\u5c0f\u3002
\n\u57fa\u672c\u7c7b\u578b\u6307\uff1achar\uff0cshort\uff0cint\uff0cfloat\uff0cdouble\u3002
\n\u6570\u636e\u5bbd\u5ea6\u5373\u5176sizeof\u7684\u5927\u5c0f\u3002<\/p>\n

eg\uff1a
\nstruct {char c;short s;float f;}A,
\nstruct{char c;float f;short s;}B;
\n\u5219sizeof(A)=?,sizeof(B)=?
\n\u89e3\uff1aA\u4e2d\uff0c
\nchar\u53601\u5b57\u8282\uff0cshort\u53602\uff0c\u5219short\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740\u7684offset\uff08\u504f\u79fb\u91cf\uff09=1\uff0c\u4e3a\u6ee1\u8db3\u51c6\u5219\uff082\uff09\uff0c\u5fc5\u987b\u6dfb\u52a0\u4e2d\u95f4\u586b\u5145\u5b57\u82821\uff1b
\nfloat\u53604\u5b57\u8282\uff0c\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740offset\uff1d(1+1+2)\u53734\uff0c\u6ee1\u8db3\u51c6\u5219\uff082\uff09\u3002
\n\u6b64\u65f6\u7ed3\u6784\u4f53\u5927\u5c0f\u4e3a\uff081+1+2+4\uff09=8\uff0c\u662f\u6700\u5bbd\u57fa\u672c\u7c7b\u578bfloat\u6574\u6570\u500d\uff0c\u6ee1\u8db3\uff083\uff09\u3002\u6240\u4ee5\u53ef\u5f97\u51fa\uff1asizeof(A)=8;
\n\u5bf9\u4e8eB\uff1aB\u4e2d\uff0c
\nchar\u53601\uff0cfloat\u53604\uff0c\u5219float\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740\u7684offset\uff1d\uff11\uff0c\u4e3a\u6ee1\u8db3\u51c6\u5219\uff082\uff09\uff0c\u5fc5\u987b\u6dfb\u52a0\u4e2d\u95f4\u586b\u5145\u5b57\u82823\uff1b
\nshort\u53602\uff0c\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740offset=(1+3+4)\u53738\uff0c\u662fshort\u6240\u5360\u5b57\u8282\u7684\u6574\u6570\u500d\uff0c\u6ee1\u8db3\u51c6\u5219\uff082\uff09\u3002
\n\u6b64\u65f6\u7ed3\u6784\u4f53\u5927\u5c0f\u4e3a\uff081+3+4+2\uff09=10\uff0c\u4e0d\u662f\u6700\u5bbd\u57fa\u672c\u7c7b\u578bfloat\u7684\u6574\u6570\u500d\uff0c\u8fd9\u65f6\uff0c\u672b\u5c3e\u5fc5\u987b\u6dfb\u52a0\u672b\u5c3e\u586b\u5145\u5b57\u82822\uff0c\u6240\u4ee5\u6700\u540e\u603b\u5927\u5c0f\u4e3a12\uff1b
\n\u603b\u7ed3\uff1a\u5206\u6790\u65f6\u53ea\u8981\u8fd9\u6837\u5373\u53ef\uff1a
\n\u5bf9\u4e8eA\uff1a1 1 2 4 \uff08\u7ea2\u8272\u4e3a\u63d2\u5165\u90e8\u5206\uff0c\u5199\u65f6\uff0c\u4e2d\u95f4\u8981\u7559\u591f\u7a7a\u683c\uff09
\n\u5bf9\u4e8eB\uff1a1 3 4 2 2
\n\u8fd9\u6837\u5c31\u53ef\u4ee5\u76f4\u89c2\u7684\u5f97\u5230\u7ed3\u6784\u4f53\u5927\u5c0f\u3002<\/p>\n

\u8fc1\u79fbeg\uff1astruct{float f;int I;short s;}C; \u5219sizeof(C)=?(\u7b54\u6848\uff1a12)<\/p>\n

\u77e5\u8bc6\u6269\u5c551\uff1a\u82e5\u51fa\u73b0\u7ed3\u6784\u4f53\u5d4c\u5957\uff0c\u5219\u51c6\u5219\uff082\uff09\u3001\uff083\uff09\u5e94\u6539\u4e3a\uff1a
\n\uff082\uff09\uff0c\u590d\u5408\u6210\u5458\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740\u7684\u504f\u79fb\u91cf\u662f\u590d\u5408\u6210\u5458\u4e2d\u6700\u5927\u57fa\u672c\u7c7b\u578b\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002
\n\uff083\uff09\uff0c\u7ed3\u6784\u4f53\u603b\u5927\u5c0f\u4e3a\u7ed3\u6784\u4f53\u6700\u5bbd\u57fa\u672c\u7c7b\u578b\u6210\u5458\u5927\u5c0f\u6574\u6570\u500d\u3002
\neg:
\nstruct
\n{
\nfloat f;
\nchar c;
\ndouble d;
\nstruct
\n{
\ndouble d1;
\nfloat f1;
\ndouble d2;
\nchar c1;
\n}A
\n}B;
\n\u5219sizeof(B)=?
\n\u89e3\uff1a
\n\u5bf9\u4e8e64\u4f4d\u673a\u5668\uff1a
\n\u5148\u8ba1\u7b97A\u5927\u5c0f\uff1a8\u3000 4 \u30004 \u30008 1 \u30007\uff08\u7ea2\u8272\u4e3a\u63d2\u5165\u90e8\u5206\uff09\uff0c\u5f97\u5230\u4e3a32\uff1b
\n\u6240\u4ee5\u5bf9\u4e8eB\uff0c\u4e00\u5f00\u59cb\u6392\u5217\u4e3a\uff1a 4 1 8 32\uff1b
\n1\u7684offset=4\uff0c\u6240\u4ee51\u4e0e8\u95f4\u8981\u6dfb\u4e0a3\u3002\u53d8\u4e3a\uff1a
\n4 1 3 8 32\uff1b
\n\u6b64\u65f68\u7684offset=8\uff0c\u6ee1\u8db3\u51c6\u52192\uff0c32\u7684offset=16\uff0c\u662fA\u4e2d\u6700\u5bbd\u57fa\u672c\u7c7b\u578bdouble\u6240\u5360\u5b57\u8282\u7684\u6574\u6570\u500d\uff0c\u6ee1\u8db3\u51c6\u52192\uff1b\u6b64\u65f6B\u5927\u5c0f\u4e3a48\uff0c\u662fB\u4e2d\u6700\u5bbd\u57fa\u672c\u7c7b\u578bdouble\u7684\u6574\u6570\u500d\uff0c\u6ee1\u8db3\u51c6\u52193.\u6240\u4ee5\u6700\u540esizeof(B)=48;<\/p>\n

\u77e5\u8bc6\u6269\u5c552\uff0c\u82e5\u7ed3\u6784\u4f53\u5185\u90e8\u51fa\u73b0\u6570\u7ec4\uff0c\u5219\u51c6\u52192\u5e94\u4e3a\uff1a
\n\uff082\uff09\uff0c\u6570\u7ec4\u76f8\u5bf9\u4e8e\u7ed3\u6784\u4f53\u9996\u5730\u5740\u7684offset\u662f\u8be5\u6570\u7ec4\u6210\u5458\u5927\u5c0f\u7684\u6574\u6570\u500d\u3002
\neg :<\/p>\n

struct {double d[2];char*c;}C; \u5219sizeof(C)=?
\n\u89e3\uff1a\u5bf9\u4e8e64\u4f4d\u673a\u5668\uff1a<\/p>\n

double\u5927\u5c0f\u4e3a8\u5b57\u8282\uff0c\u6240\u4ee5double[2]\u4e3a16\uff1b\u800c\u6307\u9488\u5927\u5c0f\u5747\u4e3a4\uff0c
\n\u6240\u4ee5C\u53ef\u6392\u5217\u4e3a\uff1a
\n16 4 4
\n\u5f97\u5230sizeof(C)=24;<\/p>\n

\u5bf9\u4e8e32\u4f4d\u673a\u5668\uff1a<\/p>\n

double\u5927\u5c0f\u4e3a8\u5b57\u8282\uff08\u62c6\u5206\u4e3a\u8fde\u4e2aint\u578b\uff09\uff0cdouble[2]\u5168\u90e8\u5c55\u5f00\uff1b\u800c\u6307\u9488\u5927\u5c0f\u5747\u4e3a4\uff0c
\n\u6240\u4ee5C\u53ef\u6392\u5217\u4e3a\uff1a
\n4 4 4 4 4
\n\u5f97\u5230sizeof(C)=20;<\/p>\n

\u5bf9\u4e8e\u5171\u7528\u4f53\uff1a\uff0832\u4f4d\u673a\u5668\u4e0b\uff09<\/pre>\n
\u539f\u5219\u4e0a\uff0c\u5171\u7528\u4f53\u5927\u5c0f\u53d6\u51b3\u4e8e\u5360\u636e\u6700\u591a\u5185\u5b58\u7684\u6210\u5458\u7684\u6240\u5360\u636e\u7684\u6570\u636e\u6bb5\u7684\u5927\u5c0f(\u6700\u5927\u7684\u90a3\u4e2a\u6570\u636e\u4ecd\u7136\u9075\u5b88\u5b57\u8282\u5bf9\u9f50\u539f\u5219)\u3002<\/pre>\n
Eg\uff1a<\/pre>\n
union uOne4All\r\n{\r\n  char nVal[10];\r\n  long dVal;\r\n}f;<\/pre>\n
\u5219sizeof(f)=12\u3002\/\/char nVal[10]\u536010\u4e2a\u5b57\u8282\u7a7a\u95f4\uff0c32\u4e3a\u673a\u5668\u9ed8\u8ba4\u56db\u5b57\u8282\u5bf9\u9f50\uff0c\u6240\u4ee5\u536012\u5b57\u8282\u7a7a\u95f4<\/p>\n
<\/pre>\n
Union { char c; int d; }e; \u5219sizeof(e)=4;<\/pre>\n
Union { char c; double d; }e; \u5219sizeof(e)=8;\/\/\u8c8c\u4f3c\u867d\u7136double\u62c6\u5206\u6210\u4e24\u4e2aint\u578b\u8ba1\u7b97\u4f46\u4efb\u7136\u662f\u4e00\u4e2a\u6574\u4f53\u3002<\/pre>\n","protected":false},"excerpt":{"rendered":"
\uff08\u539f\u6587\u94fe\u63a5http:\/\/www.jiancool.com\/article\/3076377672\/\uff09 \u5173\u4e8e\u7ed3\u6784\u4f53 […]<\/p>\n","protected":false},"author":1,"featured_media":245,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-16","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-coding"],"_links":{"self":[{"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/posts\/16","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=16"}],"version-history":[{"count":1,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/posts\/16\/revisions"}],"predecessor-version":[{"id":17,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/posts\/16\/revisions\/17"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=\/wp\/v2\/media\/245"}],"wp:attachment":[{"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.91tfboys.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}