{"id":2568,"date":"2022-03-25T18:05:06","date_gmt":"2022-03-25T10:05:06","guid":{"rendered":"https:\/\/www.clonefactor.com\/wordpress\/?p=2568"},"modified":"2022-03-25T18:05:07","modified_gmt":"2022-03-25T10:05:07","slug":"c-%e7%b0%a1%e5%96%ae%e7%90%86%e8%a7%a3-const-char-%e7%9a%84%e5%9b%9b%e7%a8%ae-pointer-%e5%bd%a2%e6%85%8b","status":"publish","type":"post","link":"https:\/\/www.clonefactor.com\/wordpress\/program\/c\/2568\/","title":{"rendered":"C++ \u7c21\u55ae\u7406\u89e3 const char \u7684\u56db\u7a2e pointer \u5f62\u614b."},"content":{"rendered":"\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">void ConstTest01() {\n\tconst char * txt = \"Hello world\";\n\tchar chr = 'C';\n\tchar chr2 = 'H';\n\n\tchar        *           c1 = &amp;chr;\t\/\/ pointer &amp; value can change.\n\tchar const  *           c2 = &amp;chr;\t\/\/ pointer can change, value CONST.\n\tchar        * const\t\tc3 = &amp;chr;\t\/\/ pointer CONST, value can change.\n\tchar const  * const\t\tc4 = &amp;chr;\t\/\/ pointer CONST, value CONST\n    \/\/ To find out the error\n\t\/\/c1++; *c1 = chr2;\n\t\/\/c2++; *c2 = chr2;\n\t\/\/c3++; *c3 = chr2;\n\t\/\/c4++; *c4 = chr2;\n}<\/pre>\n\n\n\n<p>\u7c21\u55ae\u7684\u5224\u65b7 rule : const \u5176\u5be6\u662f\u5728\u5f62\u5bb9\u524d\u4e00\u500b\u904b\u7b97\u5b50\u7684\u5132\u5b58\u72c0\u614b\u662f&#8221;\u4e0d\u80fd\u66f4\u6539&#8221;,<\/p>\n\n\n\n<p>\u6240\u4ee5 char const \u5728\u5f62\u5bb9 char \u662f\u4e0d\u80fd\u66f4\u6539\u7684\u503c.<br>char const * const \u5247\u662f \u5f62\u5bb9 char \u4e0d\u80fd\u66f4\u6539, pointer \u4e5f\u4e0d\u80fd\u66f4\u6539.<\/p>\n\n\n\n<p>\u984d\u5916\u7684\u662f const char * \u662f\u820a\u7684\u5beb\u6cd5, \u73fe\u5728\u7684 compiler \u7de8\u8b6f\u662f\u5176\u5be6\u7b49\u540c\u65bc char const *, <\/p>\n\n\n\n<p>\u800c char const * \u70ba\u751a\u9ebc\u80fd\u5920\u5403\u4e0a\u4e00\u5927\u689d\u5b57\u4e32, \u5176\u5be6\u662f\u56e0\u70ba\u9019\u7a2e\u4e0d\u80fd\u66f4\u6539\u7684\u5b57\u4e32\u503c\u6703\u5b58\u653e\u65bc memory \u4e2d\u9023\u7e8c\u7684\u5730\u5740\u4e0a.<br>\u53ef\u4ee5\u60f3\u50cf\u70ba<br>char const * ch = &#8220;Hello World&#8221;;<br>\u7b49\u540c\u65bc\u5ba3\u544a<br> char[] txt = { &#8216;H&#8217;, &#8216;e&#8217;, &#8216;l&#8217;, &#8216;l&#8217;, &#8216;o&#8217;, &#8216; &#8216;, &#8216;W&#8217;, &#8216;o&#8217;, &#8216;r&#8217;, &#8216;l&#8217;, &#8216;d&#8217;, 0 }; \\\\ string must end by zero (0) digit.<br>char const * ch = txt[0];<\/p>\n\n\n\n<p>\u800c\u6240\u8b02\u7684 ch++ \u5247\u662f\u63a7\u5236 pointer \u5728\u8a18\u61b6\u9ad4\u4f4d\u7f6e\u4e0a\u5f8c\u79fb\u4e00\u683c.<br>\u5f9e\u800c\u9054\u6210\u5b57\u4e32\u8b80\u53d6+\u4f4d\u79fb.<\/p>\n\n\n","protected":false},"excerpt":{"rendered":"<p>\u7c21\u55ae\u7684\u5224\u65b7 rule : const \u5176\u5be6\u662f\u5728\u5f62\u5bb9\u524d\u4e00\u500b\u904b\u7b97\u5b50\u7684\u5132\u5b58\u72c0\u614b\u662f&#8221;\u4e0d\u80fd\u66f4\u6539&#038;# &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-2568","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/posts\/2568","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2568"}],"version-history":[{"count":1,"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/posts\/2568\/revisions"}],"predecessor-version":[{"id":2570,"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/posts\/2568\/revisions\/2570"}],"wp:attachment":[{"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2568"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/categories?post=2568"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.clonefactor.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2568"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}