{"id":319,"date":"2023-09-16T10:32:10","date_gmt":"2023-09-16T02:32:10","guid":{"rendered":""},"modified":"2023-09-18T11:49:45","modified_gmt":"2023-09-18T03:49:45","slug":"c-%e6%95%b0%e7%bb%84%e5%88%9d%e5%a7%8b%e5%8c%96","status":"publish","type":"post","link":"https:\/\/mushiming.com\/319.html","title":{"rendered":"C++: \u6570\u7ec4\u521d\u59cb\u5316"},"content":{"rendered":"<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"display: none;\"> \n <path stroke-linecap=\"round\" d=\"M5,0 0,2.5 5,5z\" id=\"raphael-marker-block\" style=\"-webkit-tap-highlight-color: rgba(0, 0, 0, 0);\"><\/path> \n<\/svg> <\/p>\n<div class=\"toc\">\n<h3>\u6587\u7ae0\u76ee\u5f55<\/h3>\n<ul>\n<li>\n<ul>\n<li>\n<ul>\n<li>\u6808<\/li>\n<li>\u52a8\u6001\u6570\u7ec4<\/li>\n<li>\u8d4b\u503c<\/li>\n<li>\n<ul>\n<li>memset<\/li>\n<li>fill<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/div>\n<h3>\u6808<\/h3>\n<p>\u6570\u7ec4\u662f\u5e95\u5c42\u6570\u636e\u7c7b\u578b\uff0c\u5b58\u653e\u5728\u6808\u4e2d\uff0c\u5176\u5185\u5b58\u7684\u5206\u914d\u548c\u91ca\u653e\u5b8c\u5168\u7531\u7cfb\u7edf\u81ea\u52a8\u5b8c\u6210.<br \/> \u901a\u8fc7\u5982\u4e0b\u4ee3\u7801\u521d\u59cb\u5316\u4e00\u4e2a<code>\u5168\u5c40\u53d8\u91cf<\/code>\u6570\u7ec4\uff0c\u521d\u59cb\u5316\u7684\u89c4\u5219\u5c31\u662f\u4e0d\u8db3\u6570\u7ec4\u5927\u5c0f\u7684\u6309\u9ed8\u8ba4\u503c\u8865\u4f4d<\/p>\n<pre><code class=\"prism language-cpp\"><span class=\"token keyword\">int<\/span> a<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/int\u9ed8\u8ba40<\/span>\n<span class=\"token keyword\">int<\/span> b<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span> <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">{ \n   <!-- --><\/span><span class=\"token number\">1<\/span>\uff0c<span class=\"token number\">2<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ {1,2,0,0,0} \u4e0d\u8db35\u4f4d\u76840\u8865\u4f4d<\/span>\nstring c<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span> <span class=\"token operator\">=<\/span> <span class=\"token punctuation\">{ \n   <!-- --><\/span><span class=\"token string\">\"a\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"b\"<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ {\"a\",\"b\",\"\",\"\",\"\"}<\/span>\n<\/code><\/pre>\n<p>\u5982\u679c\u4e0d\u660e\u786e\u6307\u51fa\u521d\u59cb\u5316\u5217\u8868\uff0c\u90a3\u4e48\u57fa\u672c\u7c7b\u578b\u662f\u4e0d\u4f1a\u88ab\u521d\u59cb\u5316\u7684\uff08\u5168\u5c40\u53d8\u91cf\u3001\u9759\u6001\u53d8\u91cf\u5916\uff09; \u7c7b\u7c7b\u578b\u5982<code>string<\/code>\u5219\u4f1a\u4e3a\u6bcf\u4e2a\u5143\u7d20\u8c03\u7528\u9ed8\u8ba4\u6784\u9020\u51fd\u6570\u8fdb\u884c\u521d\u59cb\u5316\u3002<br \/> \u6240\u4ee5\u5efa\u8bae\u4f7f\u7528\u5982\u4e0b\u65b9\u5f0f\u521d\u59cb\u5316\uff0c\u5c40\u90e8\u53d8\u91cf\u4e5f\u4f1a\u521d\u59cb\u5316<\/p>\n<pre><code class=\"prism language-cpp\"><span class=\"token keyword\">int<\/span> a<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{ \n   <!-- --><\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/c++11\u65b0\u5199\u6cd5<\/span>\n<\/code><\/pre>\n<h3>\u52a8\u6001\u6570\u7ec4<\/h3>\n<p>\u52a8\u6001\u6570\u7ec4\u662f\u901a\u8fc7<code>new<\/code>\u521b\u5efa\u5728\u5806\u4e0a\u7684\u6570\u7ec4<\/p>\n<pre><code class=\"prism language-cpp\"><span class=\"token keyword\">int<\/span> <span class=\"token operator\">*<\/span>a <span class=\"token operator\">=<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token keyword\">int<\/span><span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/\u6ca1\u6709\u521d\u59cb\u5316<\/span>\n<span class=\"token keyword\">int<\/span> <span class=\"token operator\">*<\/span>b <span class=\"token operator\">=<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token keyword\">int<\/span><span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span> <span class=\"token punctuation\">{ \n   <!-- --><\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">,<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ {1,2,0,0,0} \u4e0d\u8db35\u4f4d\u76840\u8865\u4f4d<\/span>\nstring <span class=\"token operator\">*<\/span>c <span class=\"token operator\">=<\/span> <span class=\"token keyword\">new<\/span> string<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">{ \n   <!-- --><\/span><span class=\"token string\">\"a\"<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token string\">\"b\"<\/span><span class=\"token punctuation\">}<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ {\"a\",\"b\",\"\",\"\",\"\"}<\/span>\n<\/code><\/pre>\n<p>\u52a8\u6001\u6570\u7ec4\u5982\u679c\u4e0d\u660e\u786e\u6307\u51fa\u521d\u59cb\u5316\u5217\u8868\uff0c\u90a3\u4e48\u57fa\u672c\u7c7b\u578b\u662f\u4e0d\u4f1a\u88ab\u521d\u59cb\u5316\u7684\uff08\u5168\u5c40\u53d8\u91cf\u4e5f\u6ca1\u6709\u521d\u59cb\u5316\uff0c\u9759\u6001\u53d8\u91cf\u5916\uff09\uff0c\u6240\u6709\u7684\u5185\u5b58\u90fd\u662f\u201c\u810f\u7684\u201d\u3002<br \/> <code>new<\/code>\u8fd8\u6709\u4e00\u79cd\u5199\u6cd5\uff0c\u4f1a\u521d\u59cb\u5316<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-cpp\"><span class=\"token keyword\">int<\/span><span class=\"token operator\">*<\/span> a <span class=\"token operator\">=<\/span> <span class=\"token keyword\">new<\/span> <span class=\"token keyword\">int<\/span><span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">(<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><span class=\"token comment\">\/\/\u521d\u59cb\u5316{0,0,0,0,0}<\/span>\n<\/code><\/pre>\n<p>\u52a0\u4e86\u62ec\u53f7\u7684\u610f\u601d\u662f\u4f7f\u7528\u9ed8\u8ba4\u503c\u521d\u59cb\u5316\u6574\u4e2a\u6570\u7ec4<\/p>\n<h3>\u8d4b\u503c<\/h3>\n<h4>memset<\/h4>\n<p><code>memset<\/code>\u53ef\u4ee5\u4e3a\u4e0a\u8ff0\u6570\u7ec4\u91cd\u7f6e\uff0c\u7531\u4e8e<code>memset<\/code>\u6309\u5b57\u8282\u5bf9\u5185\u5b58\u5757\u8fdb\u884c\u521d\u59cb\u5316\uff0c\u6240\u4ee5\u4e0d\u80fd\u7528\u5b83\u5c06int\u6570\u7ec4\u521d\u59cb\u5316\u4e3a0\u548c-1\u4e4b\u5916\u7684\u5176\u4ed6\u503c\uff08\u9664\u975e\u8be5\u503c\u9ad8\u5b57\u8282\u548c\u4f4e\u5b57\u8282\u76f8\u540c\uff09\u3002<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-cpp\"><span class=\"token function\">memset<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">void<\/span> <span class=\"token operator\">*<\/span>s<span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">int<\/span> ch<span class=\"token punctuation\">,<\/span>size_t n<span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span>\n<span class=\"token keyword\">int<\/span> a<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span>\n<span class=\"token function\">memset<\/span><span class=\"token punctuation\">(<\/span>a<span class=\"token punctuation\">,<\/span> <span class=\"token number\">511<\/span><span class=\"token punctuation\">,<\/span> <span class=\"token keyword\">sizeof<\/span><span class=\"token punctuation\">(<\/span><span class=\"token keyword\">int<\/span><span class=\"token punctuation\">)<\/span><span class=\"token operator\">*<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span><span class=\"token comment\">\/\/ 511\u7684\u4e8c\u8fdb\u5236\u7801\u540e\u516b\u4f4d\u90fd\u4e3a1\uff0c\u4e0e-1\u76f8\u540c<\/span>\n<span class=\"token comment\">\/\/{-1,-1,-1,-1,-1}<\/span>\n<\/code><\/pre>\n<p><code>memset<\/code>\u8d4b\u503c\u91c7\u7528\u8f93\u5165\u7684\u7b2c\u56db\u4e2a\u5b57\u8282\uff0c\u56e0\u4e3a511\u4e8c\u8fdb\u5236\u7801 (00000000 00000000 00000001 11111111)\uff0c\u6700\u540e\u4e00\u4e2a\u5b57\u8282\u4e0e1\u7684\u4e8c\u8fdb\u5236\u7801 (11111111 11111111 11111111 11111111)\uff0c\u56db\u4e2a\u5b57\u8282\u90fd\u76f8\u540c\uff0c\u6240\u4ee5\u53ef\u4ee5\u8d4b\u503c\u3002<br \/> \u524d\u9762\u63d0\u8fc7\uff0c\u5982\u679c\u6211\u4eec\u60f3\u521d\u59cb\u5316\u7684\u503c\u9ad8\u4f4d\u5b57\u8282\u548c\u4f4e\u4f4d\u5b57\u8282\u76f8\u540c(0\u548c-1\u7684\u6bcf\u4e2a\u5b57\u8282\u90fd\u76f8\u540c)\uff0c\u4e5f\u53ef\u4ee5\u7528<code>memset<\/code>\u8d4b\u503c\u3002<\/p>\n<h4>fill<\/h4>\n<p>fill() \u548c fill_n() \u7b97\u6cd5\u63d0\u4f9b\u4e86\u4e00\u79cd\u4e3a\u5143\u7d20\u5e8f\u5217\u586b\u5165\u7ed9\u5b9a\u503c\u7684\u7b80\u5355\u65b9\u5f0f\uff0c\u53ef\u4ee5\u7528\u4e8e\u591a\u79cd\u5e8f\u5217\uff0c\u8fd9\u91cc\u5217\u51fa\u521d\u59cb\u5316\u6570\u7ec4\u7684\u6837\u4f8b\uff0c\u611f\u5174\u8da3\u518d\u505a\u63a2\u7d22<\/p>\n<pre class=\"language-java prettyprint linenums\"><code class=\"prism language-cpp\"><span class=\"token keyword\">int<\/span> a<span class=\"token punctuation\">[<\/span><span class=\"token number\">5<\/span><span class=\"token punctuation\">]<\/span><span class=\"token punctuation\">;<\/span><span class=\"token comment\">\/\/\u8fd9\u91cca\u6309\u5168\u5c40\u53d8\u91cf\u5b9a\u4e49\uff0c\u5219\u90fd\u521d\u59cb\u5316\u4e3a0<\/span>\n<span class=\"token function\">fill<\/span><span class=\"token punctuation\">(<\/span>a<span class=\"token punctuation\">,<\/span>a<span class=\"token operator\">+<\/span><span class=\"token number\">2<\/span><span class=\"token punctuation\">,<\/span><span class=\"token number\">1<\/span><span class=\"token punctuation\">)<\/span><span class=\"token punctuation\">;<\/span> <span class=\"token comment\">\/\/ {1,1,0,0,0}<\/span>\n<\/code><\/pre>\n<p>\u53c2\u8003<br \/> memset<br \/> C\/C++\u6570\u7ec4\u521d\u59cb\u5316\u7684\u4e00\u4e9b\u8bef\u533a<br \/> C++ fill\u548cfill_n\u51fd\u6570\u7528\u6cd5\u8be6\u89e3<\/p>\n","protected":false},"excerpt":{"rendered":"C++: \u6570\u7ec4\u521d\u59cb\u5316\u6587\u7ae0\u76ee\u5f55\u6808\u52a8\u6001\u6570\u7ec4\u8d4b\u503cmemsetfill\u6808\u6570\u7ec4\u662f\u5e95\u5c42\u6570\u636e\u7c7b\u578b\uff0c\u5b58\u653e\u5728\u6808\u4e2d\uff0c\u5176\u5185\u5b58\u7684\u5206\u914d\u548c\u91ca\u653e\u5b8c\u5168\u7531\u7cfb\u7edf\u81ea\u52a8\u5b8c\u6210...","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"_links":{"self":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/319"}],"collection":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/comments?post=319"}],"version-history":[{"count":0,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/posts\/319\/revisions"}],"wp:attachment":[{"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/media?parent=319"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/categories?post=319"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mushiming.com\/wp-json\/wp\/v2\/tags?post=319"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}