{"id":317,"date":"2020-03-21T11:12:19","date_gmt":"2020-03-21T03:12:19","guid":{"rendered":"https:\/\/www.notown.club\/?p=317"},"modified":"2020-08-22T11:02:06","modified_gmt":"2020-08-22T03:02:06","slug":"c%e5%8f%98%e9%87%8f%e5%92%8c%e5%9f%ba%e6%9c%ac%e7%b1%bb%e5%9e%8b%ef%bc%88%e7%ac%94%e8%ae%b0%e4%b8%80%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.notown.top\/?p=317","title":{"rendered":"C++\u53d8\u91cf\u548c\u57fa\u672c\u7c7b\u578b\uff08\u7b14\u8bb0\u4e00\uff09"},"content":{"rendered":"\n

\u4e00\u3001\u65e0\u7b26\u53f7\u548c\u4e0e\u7b26\u53f7<\/strong><\/p>\n\n\n\n


  \u7ed9\u4e00\u4e2a\u65e0\u7b26\u53f7\u7c7b\u578b<\/strong>\u8d4b\u4e00\u4e2a\u8d85\u51fa\u5176\u8868\u793a\u8303\u56f4\u7684\u503c\u65f6\uff0c\u7ed3\u679c\u662f\u8303\u56f4\u603b\u6570\u548c\u8fd9\u4e2a\u503c\u53d6\u4f59
  \u7ed9\u4e00\u4e2a\u6709\u7b26\u53f7\u7684\u7c7b\u578b<\/strong>\u8d4b\u4e00\u4e2a\u8d85\u51fa\u5176\u8303\u56f4\u7684\u503c\u65f6\uff0c\u7ed3\u679c\u662f\u672a\u5b9a\u4e49\u3002
\u5f53\u6709\u7b26\u53f7\u7c7b\u578b\u548c\u65e0\u7b26\u53f7\u7c7b\u578b\u505a\u8fd0\u7b97\u65f6\uff0c\u90fd\u4f1a\u5148\u8f6c\u6210\u65e0\u7b26\u53f7\u6570\uff08\u8d1f\u6570\u4f1a\u5148\u88ab\u52a0\u4e0a\u8303\u56f4\u603b\u6570\uff09<\/p>\n\n\n\n

\u4e8c\u3001\u5bf9\u4e8e\u5b57\u7b26\u4e32<\/strong><\/p>\n\n\n\n

  \u7f16\u8bd1\u5668\u4f1a\u5728\u6bcf\u4e2a\u5b57\u7b26\u4e32\u7684\u7ed3\u5c3e\u5904\u6dfb\u52a0\u4e00\u4e2a\u7a7a\u5b57\u7b26(‘\\0’)\uff0c\u5b57\u7b26\u4e32\u5b57\u9762\u503c\u7684\u7c7b\u578b\u5b9e\u9645\u957f\u5ea6\u8981\u6bd4\u5b83\u7684\u5185\u5bb9\u591a1\uff0c\u4f8b\uff1a\u5b57\u9762\u503c\u2019A\u2019\u8868\u793a\u7684\u5c31\u662f\u5355\u72ec\u7684\u5b57\u7b26A\u3001\u800c\u5b57\u7b26\u4e32\u201dA\u201d\u5219\u4ee3\u8868\u4e86\u4e00\u4e2a\u5b57\u7b26\u7684\u6570\u7ec4\uff0c\u8be5\u6570\u7ec4\u5305\u542b\u4e24\u4e2a\u5b57\u7b26\uff1a\u4e00\u4e2a\u662f\u5b57\u6bcdA\u3001\u53e6\u4e00\u4e2a\u662f\u7a7a\u5b57\u7b26\u3002<\/p>\n\n\n\n

\u4e09\u3001\u5bf9\u4e8e\u5b57\u7b26\u4e32\u5b57\u9762\u503c<\/strong><\/p>\n\n\n\n

\\\u7528\u6765\u8f6c\u4e49\u7684\u65f6\u5019
\\\u540e\u9762\u82e5\u76f4\u63a5\u8ddf\u6570\u5b57\uff0c\u5219\u4e3a\u516b\u8fdb\u5236\u7684\u6570\u5b57\uff08\u6700\u591a\u4e09\u4f4d\uff09\uff0c\u5982\\115\u5373\u662fM
\\\u540e\u9762\u4e5f\u53ef\u8ddf16\u8fdb\u5236\uff0c\u5982\\x4d\u4e5f\u662fM<\/strong>
\u5176\u4ed6\u5e38\u7528\uff1a
\\12 \u6362\u884c\u7b26          \\40 \u7a7a\u683c          \\0 \u7a7a\u5b57\u7b26
\u8fd8\u53ef\u901a\u8fc7\u6dfb\u52a0\u524d\u7f00\u6216\u540e\u6700\u6539\u53d8\u5b57\u9762\u503c\u7c7b\u578b\uff1a
\u4f8b\uff1a
L’a’ \/\/\u5bbd\u5b57\u7b26\u578b\u5b57\u9762\u503c
3.14159L \/\/\u6269\u5c55\u7cbe\u5ea6\u6d6e\u70b9\u578b\u5b57\u9762\u503c<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

\u4e09\u3001\u5b9a\u4e49\u4e86\u4f46\u662f\u6ca1\u88ab\u663e\u5f0f\u521d\u59cb\u5316\u7684\u53d8\u91cf\uff0c\u5b83\u7684\u503c\u662f\u4ec0\u4e48<\/strong><\/p>\n\n\n\n

  \u5982\u679c\u662f\u5185\u7f6e\u7c7b\u578b\u7684\u53d8\u91cf\u672a\u88ab\u663e\u5f0f\u521d\u59cb\u5316\uff0c\u5b83\u7684\u503c\u7531\u5b9a\u4e49\u7684\u4f4d\u7f6e\u51b3\u5b9a\uff1b\u82e5\u662f\u5168\u5c40\u53d8\u91cf<\/strong>\uff0c\u5219\u9ed8\u8ba4\u4e3a0<\/strong>\uff0c\u82e5\u662f\u51fd\u6570\u5185\u7684\u53d8\u91cf<\/strong>\uff0c\u5219\u5176\u5b9e\u5728\u8d4b\u503c\u4e4b\u524d\u662f\u4e0d\u53ef\u7528<\/strong>\u7684\u3002
\u5982\u679c\u662f\u975e\u5185\u7f6e\u7c7b\u578b<\/strong>\u7684\u53d8\u91cf\u672a\u88ab\u663e\u793a\u521d\u59cb\u5316\uff08\u4f8bstring\u578b\uff09\uff0c\u5219\u53ef\u80fd\u5728\u8d4b\u503c\u4e4b\u524d\u65e0\u8bba\u5728\u5185\u5728\u5916\u90fd\u662f\u4e0d\u53ef\u7528\u7684<\/strong>\u3002<\/p>\n\n\n\n

\u56db\u3001\u5173\u4e8e\u53d8\u91cf\u7684\u547d\u540d <\/strong><\/p>\n\n\n\n

C++\u7684\u6807\u8bc6\u7b26\u7531\u5b57\u6bcd\u3001\u6570\u5b57\u3001\u4e0b\u5212\u7ebf\u7ec4\u6210\uff0c\u5176\u4e2d\u5fc5\u987b\u4ee5\u5b57\u6bcd\u6216\u4e0b\u5212\u7ebf\u5f00\u5934\uff0c\u5bf9\u5927\u5c0f\u5199\u654f\u611f\u3002
\u7528\u6237\u81ea\u5b9a\u4e49\u7684\u6807\u8bc6\u7b26\u4e0d\u80fd\u8fde\u7eed\u51fa\u73b0\u4e24\u4e2a\u4e0b\u5212\u7ebf<\/strong><\/p>\n\n\n\n

\u4e94\u3001\u5173\u4e8e\u6307\u9488<\/strong><\/p>\n\n\n\n

(1)\u751f\u6210\u7a7a\u6307\u9488\u7684\u4e09\u4e2a\u65b9\u6cd5\uff1a
\u751f\u6210\u7a7a\u6307\u9488\uff1a<\/p>\n\n\n\n

 1\u3001int *p =nullptr\n 2\u3001int *p =0\n 3\u3001int *p =null\uff08\u5c3d\u91cf\u4e0d\u7528\uff09<\/code><\/pre>\n\n\n\n
(2)\u6307\u9488\u7684\u5f15\u7528\uff1a<\/p>\n\n\n\n
int i =42; 
int *p; 
int *&r =p;\/\/r\u662f\u4e00\u4e2a\u6307\u9488p\u7684\u5f15\u7528\/\/\u8981\u7406\u89e3r\u7684\u7c7b\u578b\u662f\u4ec0\u4e48\uff0c\u6700\u7b80\u5355\u7684\u529e\u6cd5\u5c31\u662f\u5148\u8bfb
                   \/\/\u79bbr\u6700\u8fd1\u7684\u5b9a\u4e49\uff0c\u5373& 
r=&i;\/\/\u76f8\u5f53\u4e8e\u5c06\u6307\u9488p\u6307\u5411i
*r=0;\/\/\u76f8\u5f53\u4e8ei=0<\/pre>\n\n\n\n
\u516d\u3001const<\/strong><\/p>\n\n\n\n
const\u5bf9\u8c61\u521d\u59cb\u5316\u65f6\u5fc5\u987b\u8d4b\u503c 
\u5982\u679c\u5229\u7528\u4e00\u4e2a\u5bf9\u8c61\u53bb\u521d\u59cb\u5316\u53e6\u4e00\u4e2a\u5bf9\u8c61\uff0c\u5219\u4ed6\u4eec\u662f\u4e0d\u662fconst\u5bf9\u8c61\u90fd\u65e0\u5173\u7d27\u8981
\u5173\u4e8e\u5e38\u91cf\u3001\u5f15\u7528\u3001\u521d\u59cb\u5316\uff1a<\/p>\n\n\n\n
int i =42;\nconst int &r1=i;\/\/\u6b63\u786e\uff0c\u5141\u8bb8\u5c06const int& \u7ed1\u5b9a\u5230\u4e00\u4e2a\u666e\u901aint\u5bf9\u8c61\u4e0a\nconst int &r2=42;\/\/\u6b63\u786e\uff0cr2\u662f\u4e00\u4e2a\u5e38\u91cf\u5f15\u7528\nconst int &r3=r2;\/\/\u6b63\u786e\uff0cr3\u662f\u4e00\u4e2a\u5e38\u91cf\u5f15\u7528<\/em>\nint &r4=r2;\/\/\u9519\u8bef\nint &r4=r1*2;\/\/\u9519\u8bef<\/pre>\n\n\n\n
\u4e2a\u4eba\u7406\u89e3\uff1a
 \u00a0\u5982\u679c\u662f\u975e\u5e38\u91cf\u5f15\u7528\u53ea\u80fd\u7ed1\u5b9a\u975e\u5e38\u91cf\uff0c\u5982\u679c\u662f\u5e38\u91cf\u5f15\u7528\uff0c\u5219\u5728\u7b49\u53f7\u7684\u53f3\u8fb9\u53ef\u4ee5\u662f\u4efb\u610f\u7684\uff0c\u53ef\u4ee5\u662f\u975e\u5e38\u91cf\u53d8\u91cf\uff08\u53ea\u4f1a\u53d6\u5f53\u524d\u503c\uff09\uff0c\u53ef\u4ee5\u662f\u6570\u503c\uff0c\u53ef\u4ee5\u662f\u5e38\u91cf\u5bf9\u8c61\u3002\u7b80\u5355\u70b9\u6765\u8bb0\u5462\uff0c\u5c31\u662f\uff0c\u975e\u5e38\u91cf\u5f15\u7528\u4e0d\u53ef\u4ee5\u7ed1\u5b9a\u5e38\u91cf\uff08\u56e0\u4e3a\u4e0d\u53ef\u4ee5\u901a\u8fc7\u5f15\u7528\u6539\u53d8\u5e38\u91cf\uff09\uff0c\u5bf9\u4e8e\u5e38\u91cf\u5f15\u7528\u5462\uff0c\u6211\u89c9\u5f97\u5dee\u4e0d\u591a\u53ef\u4ee5\u8bf4\u76f8\u5f53\u4e8e\u5b8f\u5b9a\u4e49define\u7684\u4f5c\u7528\uff0c\u521d\u59cb\u5316\u65f6\u53ea\u8981\u7b49\u53f7\u53f3\u8fb9\u662f\u4e00\u4e2a\u6570\u503c\u5c31\u53ef\u3002\uff08\u6240\u8ff0\u7684\u5e38\u91cf\u5f15\u7528\u3001\u975e\u5e38\u91cf\u5f15\u7528\u5e94\u7406\u89e3\u4e3a\u5bf9\u5e38\u91cf\u7684\u5f15\u7528\u3001\u5bf9\u975e\u5e38\u91cf\u7684\u5f15\u7528\uff09<\/p>\n\n\n\n
\u4e03\u3001const+\u6307\u9488<\/strong><\/p>\n\n\n\n
const double pi = 3.14\uff1b
double *ptr =&pi\/\/\u9519\u8bef\uff0cptr\u662f\u666e\u901a\u6307\u9488\uff0c\u4e0d\u53ef\u6307\u5411\u5e38\u91cf
const double *cptr =\u03c0\/\/\u6b63\u786e
*cptr =42;\/\/\u9519\u8bef\uff0c\u4e0d\u53ef\u4ee5\u6539\u53d8\u5e38\u91cf
double dval =3.14;\/\/
cptr =&dval;\/\/\u6b63\u786e\uff0c\u53ef\u4ee5\u91cd\u65b0\u6307\u5411\u5176\u4ed6\u53d8\u91cf\uff0c\u4f46\u662f\u4f9d\u65e7\u4e0d\u80fd\u901a\u8fc7\u8be5\u6307\u9488\u6539\u53d8\u8be5\u6307\u9488\u6307\u5411\u7684\u503c<\/pre>\n\n\n\n
\u4e2a\u4eba\u7406\u89e3
  \u5bf9\u4e8e\u6307\u9488\u4e5f\u4e00\u6837\uff0c\u5e38\u91cf\u503c\u5fc5\u987b\u53ea\u80fd\u7531const int\u6307\u9488\u6307\u5411\uff0c\u8868\u660e\u6307\u5411\u7684\u503c\u662f\u5e38\u91cf\uff0c\u76f4\u63a5\u4fee\u6539\u6216\u8005\u901a\u8fc7\u6307\u9488\u4fee\u6539\u90fd\u662f\u4e0d\u5141\u8bb8\u7684\u3002\u4f46\u662f\u5e38\u91cf\u6307\u9488\u53ef\u4ee5\u91cd\u65b0\u6307\u5411\u5176\u4ed6\u53d8\u91cf
\u6307\u5411\u5e38\u91cf\u7684\u6307\u9488 const int *p    \uff1a\u6307\u5411\u7684\u503c\u4e3a\u5e38\u91cf\uff0c\u4e0d\u53ef\u6539\u53d8
\u5e38\u91cf\u6307\u9488 int *const p          \uff1a\u6307\u9488\u672c\u8eab\u6240\u5b58\u7684\u5730\u5740\u4e0d\u53ef\u6539\u53d8\uff0c\u5c06\u4e00\u76f4\u6307\u5411\u67d0\u4e2a\u53d8\u91cf
 \u5e38\u91cf\u6307\u9488\u5fc5\u987b\u5728\u521d\u59cb\u5316\u7684\u65f6\u5019\u5c31\u8d4b\u5730\u5740\u3002 <\/p>\n\n\n\n
\u516b\u3001\u9876\u5c42const\u548c\u5e95\u5c42const<\/strong><\/p>\n\n\n\n
  const\u4e5f\u5206\u9876\u5c42const\u548c\u5e95\u5c42const\uff0c\u9876\u5c42const\u662f\u6307\u5bf9\u8c61\u672c\u8eab\u662f\u5e38\u91cf\uff0c\u4e0d\u80fd\u88ab\u6539\u53d8\uff1b\u5e95\u5c42const\u662f\u6307\u5411\u7684\u5bf9\u8c61\u662f\u5e38\u91cf\uff0c\u6070\u597d\u6307\u9488\u6709\u4e24\u5c42const\u3002<\/p>\n\n\n\n
int num = 5;<\/code>\nconst int* i = #<\/code>\/\/\u5e95\u5c42const\uff0c\u628a\u6307\u5411\u7684\u5bf9\u8c61\u770b\u4f5c\u5e38\u91cf\uff0c\u4e0d\u80fd\u901a\u8fc7*i\u6765\u6539num\u7684\u503c\nint *const j = #<\/code>\/\/\u9876\u5c42const\uff0c\u6307\u9488j\u672c\u8eab\u5c31\u662f\u5e38\u91cf\uff0c\u4e0d\u80fd\u5c06j\u6307\u5411\u522b\u7684\u4e1c\u897f\u4e86\u3002<\/pre>\n","protected":false},"excerpt":{"rendered":"
\u4e00\u3001\u65e0\u7b26\u53f7\u548c\u4e0e\u7b26\u53f7   \u7ed9\u4e00\u4e2a\u65e0\u7b26\u53f7\u7c7b\u578b\u8d4b\u4e00\u4e2a\u8d85\u51fa\u5176\u8868\u793a\u8303\u56f4\u7684\u503c\u65f6\uff0c\u7ed3\u679c\u662f\u8303\u56f4\u603b\u6570\u548c\u8fd9\u4e2a\u503c…Continue reading C++\u53d8\u91cf\u548c\u57fa\u672c\u7c7b\u578b\uff08\u7b14\u8bb0\u4e00\uff09<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[11],"tags":[],"class_list":["post-317","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts\/317","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=317"}],"version-history":[{"count":15,"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts\/317\/revisions"}],"predecessor-version":[{"id":515,"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts\/317\/revisions\/515"}],"wp:attachment":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=317"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=317"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}