{"id":207542,"date":"2025-07-08T11:32:07","date_gmt":"2025-07-08T03:32:07","guid":{"rendered":"https:\/\/server.hk\/cnblog\/207542\/"},"modified":"2025-07-08T11:32:07","modified_gmt":"2025-07-08T03:32:07","slug":"%e4%bd%8d%e7%a7%bb%e4%bd%8d-%e5%92%8c%e4%b9%98%e6%b3%95-%e4%bc%98%e5%85%88%e7%ba%a7","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/207542\/","title":{"rendered":"\u4f4d\u79fb\u4f4d << \u548c\u4e58\u6cd5 * \u4f18\u5148\u7ea7"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> \u4f4d\u79fb\u4f4d << \u548c\u4e58\u6cd5 * \u4f18\u5148\u7ea7<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-04-23 14:42:35<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u73cd\u60dc\u65f6\u95f4\uff0c\u52e4\u594b\u5b66\u4e60\uff01\u4eca\u5929\u7ed9\u5927\u5bb6\u5e26\u6765\u300a\u4f4d\u79fb\u4f4d \uff0c\u6b63\u6587\u5185\u5bb9\u4e3b\u8981\u6d89\u53ca\u5230<\/span>\u7b49\u7b49\uff0c\u5982\u679c\u4f60\u6b63\u5728\u5b66\u4e60Golang<\/span>\uff0c\u6216\u8005\u662f\u5bf9Golang<\/span>\u6709\u7591\u95ee\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u6211\uff01\u540e\u9762\u6211\u4f1a\u6301\u7eed\u66f4\u65b0\u76f8\u5173\u5185\u5bb9\u7684\uff0c\u5e0c\u671b\u90fd\u80fd\u5e2e\u5230\u6b63\u5728\u5b66\u4e60\u7684\u5927\u5bb6\uff01<\/span><\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

\u5728 go \u6f14\u793a\u4e2d\u5c1d\u8bd5\u4e86\u6b64\u4ee3\u7801\uff1a<\/p>\n

package main\n\nimport (\n    \"fmt\"\n)\n\nfunc main() {\n    log2dim := uint32(9)\n    \n    size := 1 << 3 * log2dim\n    fmt.printf(\"result: %v\\n\", size)\n    \n    size = 1 << (3 * log2dim)            \/\/ => only difference: adding ( )\n    fmt.printf(\"result: %v\\n\", size)\n}\n<\/pre>\n
\u6253\u5370\u51fa\u6765\u7684\u662f\uff1a<\/p>\n
Result: 72\nResult: 134217728<\/pre>\n
\u4e3a\u4ec0\u4e48\u5728\u5305\u542b <<<\/code> \u548c *<\/code> \u64cd\u4f5c\u7684\u8bed\u53e5\u4e2d\u6dfb\u52a0 ( )<\/code> \u4f1a\u4ea7\u751f\u5de8\u5927\u7684\u5dee\u5f02\uff1f<\/p>\n
\u636e\u6b64\uff0c*<\/code> \u7684\u4f18\u5148\u7ea7\u9ad8\u4e8e <<<\/code>\uff0c\u8fd9\u662f google \u641c\u7d22 bitshiftpriorence golang \u7684\u7b2c\u4e00\u4e2a\u7ed3\u679c\u3002<\/p>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
\u60a8\u94fe\u63a5\u5230\u7684\u9875\u9762\u662f\u9519\u8bef\u7684\u3002 go \u53ea\u6709\u4e00\u4e2a\u89c4\u8303\uff0c\u5173\u4e8e \u7684\u8bf4\u660e\u975e\u5e38\u6e05\u695a\uff1a<\/p>\n
\u4e8c\u5143\u8fd0\u7b97\u7b26\u6709\u4e94\u4e2a\u4f18\u5148\u7ea7\u3002\u4e58\u6cd5\u8fd0\u7b97\u7b26\u7ed1\u5b9a\u6700\u5f3a\uff0c\u5176\u6b21\u662f\u52a0\u6cd5\u8fd0\u7b97\u7b26\u3001\u6bd4\u8f83\u8fd0\u7b97\u7b26\u3001&&\uff08\u903b\u8f91\u4e0e\uff09\uff0c\u6700\u540e\u662f || \uff08\u903b\u8f91\u6216\uff09\uff1a<\/p>\n
5             *  \/  %  <<  >>  &  &^\n    4             +  -  |  ^\n    3             ==  !=  <  <=  >  >=\n    2             &&\n    1             ||<\/pre>\n
\u76f8\u540c\u4f18\u5148\u7ea7\u7684\u4e8c\u5143\u8fd0\u7b97\u7b26\u4ece\u5de6\u5230\u53f3\u5173\u8054\u3002\u4f8b\u5982\uff0cx \/ y * z \u4e0e (x \/ y) * z \u76f8\u540c\u3002<\/p>\n
\u4e58\u6cd5\u548c\u4f4d\u79fb\u4f4d\u5177\u6709\u76f8\u540c\u7684\u4f18\u5148\u7ea7\uff0c\u56e0\u6b64\u5e94\u7528\u201c\u4ece\u5de6\u5230\u53f3\u201d\u89c4\u5219\uff0c\u4f7f\u60a8\u7684\u4ee3\u7801\u76f8\u5f53\u4e8e (1 << 3) * log2dim<\/code><\/p>\n
\u8bf7\u6ce8\u610f\uff0c\u4ece\u5de6\u5230\u53f3<\/em>\u8868\u793a\u5728\u4ee3\u7801\u4e2d<\/em>\uff0c\u800c\u4e0d\u662f\u5728\u4f18\u5148\u7ea7\u8868\u4e2d<\/em>\u3002\u4ece\u89c4\u8303\u4e2d\u7ed9\u51fa\u7684\u793a\u4f8b\u53ef\u4ee5\u770b\u51fa\u8fd9\u4e00\u70b9\u3002<\/p>\n
\u4e8c\u5143\u8fd0\u7b97\u7b26\u6709\u4e94\u4e2a\u4f18\u5148\u7ea7\u3002 *<\/code> \u548c <<<\/code> \u5177\u6709\u76f8\u540c\u7684\u4f18\u5148\u7ea7\uff1a 5. \u76f8\u540c\u4f18\u5148\u7ea7\u7684\u4e8c\u5143\u8fd0\u7b97\u7b26\u4ece\u5de6\u5230\u53f3\u5173\u8054\uff0c\u56e0\u6b64 1 << 3 * log2dim<\/code> \u76f8\u5f53\u4e8e (1 << 3) * log2dim<\/code>\u3002<\/p>\n
\u6765\u6e90\uff1a<\/p>\n
\u4ee5\u4e0a\u5c31\u662f\u300a\u4f4d\u79fb\u4f4d <\/p>\n","protected":false},"excerpt":{"rendered":"
\u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-207542","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207542","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=207542"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207542\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=207542"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=207542"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=207542"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}