{"id":3413,"date":"2025-04-01T23:29:22","date_gmt":"2025-04-01T15:29:22","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=3413"},"modified":"2025-04-01T23:29:22","modified_gmt":"2025-04-01T15:29:22","slug":"c-%e8%af%ad%e8%a8%80%e5%85%b1%e7%94%a8%e4%bd%93%ef%bc%88union%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/04\/01\/c-%e8%af%ad%e8%a8%80%e5%85%b1%e7%94%a8%e4%bd%93%ef%bc%88union%ef%bc%89\/","title":{"rendered":"C \u8bed\u8a00\u5171\u7528\u4f53\uff08Union\uff09"},"content":{"rendered":"\n<p>\u5728 C \u8bed\u8a00\u4e2d\uff0c<strong>\u5171\u7528\u4f53\uff08Union\uff09<\/strong> \u662f\u4e00\u79cd\u6570\u636e\u7ed3\u6784\uff0c\u5b83\u5141\u8bb8\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b\u5b58\u50a8\u5728\u540c\u4e00\u5757\u5185\u5b58\u533a\u57df\u4e2d\u3002\u4e0e\u7ed3\u6784\u4f53\u4e0d\u540c\u7684\u662f\uff0c<strong>\u5171\u7528\u4f53\u7684\u6240\u6709\u6210\u5458\u5171\u4eab\u76f8\u540c\u7684\u5185\u5b58\u7a7a\u95f4<\/strong>\uff0c\u56e0\u6b64\u5b83\u4eec\u7684\u5927\u5c0f\u7b49\u4e8e\u6700\u5927\u6210\u5458\u7684\u5927\u5c0f\uff0c\u800c\u7ed3\u6784\u4f53\u7684\u5927\u5c0f\u662f\u6240\u6709\u6210\u5458\u5927\u5c0f\u4e4b\u548c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1. C \u5171\u7528\u4f53\u7684\u5b9a\u4e49<\/strong><\/h3>\n\n\n\n<p>\u5171\u7528\u4f53\u7684\u5b9a\u4e49\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>union UnionName {\n    dataType member1;\n    dataType member2;\n    ...\n};<\/code><\/pre>\n\n\n\n<p>\u5176\u4e2d\uff0c<code>UnionName<\/code> \u662f\u5171\u7528\u4f53\u7684\u540d\u79f0\uff0c<code>member1<\/code>, <code>member2<\/code> \u7b49\u662f\u5171\u7528\u4f53\u7684\u6210\u5458\uff0c\u6bcf\u4e2a\u6210\u5458\u7684\u6570\u636e\u7c7b\u578b <code>dataType<\/code> \u53ef\u4ee5\u4e0d\u540c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>2. \u5171\u7528\u4f53\u7684\u7279\u6027<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u5185\u5b58\u5171\u4eab<\/strong>\uff1a\u5171\u7528\u4f53\u7684\u6240\u6709\u6210\u5458\u5171\u4eab\u540c\u4e00\u5757\u5185\u5b58\uff0c\u53ea\u6709\u4e00\u4e2a\u6210\u5458\u53ef\u4ee5\u5728\u67d0\u4e00\u65f6\u523b\u5b58\u50a8\u6709\u6548\u6570\u636e\u3002<\/li>\n\n\n\n<li><strong>\u5927\u5c0f<\/strong>\uff1a\u5171\u7528\u4f53\u7684\u5927\u5c0f\u7b49\u4e8e\u5176\u6700\u5927\u6210\u5458\u7684\u5927\u5c0f\uff0c\u56e0\u4e3a\u5b83\u4f1a\u6839\u636e\u6700\u5927\u6210\u5458\u7684\u5927\u5c0f\u6765\u5206\u914d\u5185\u5b58\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>3. \u5171\u7528\u4f53\u7684\u4f8b\u5b50<\/strong><\/h3>\n\n\n\n<pre class=\"wp-block-code\"><code>#include &lt;stdio.h&gt;\n\n\/\/ \u5b9a\u4e49\u4e00\u4e2a\u5171\u7528\u4f53\nunion Data {\n    int i;\n    float f;\n    char str&#91;20];\n};\n\nint main() {\n    \/\/ \u521b\u5efa\u5171\u7528\u4f53\u53d8\u91cf\n    union Data data;\n\n    \/\/ \u7ed9 int \u7c7b\u578b\u6210\u5458\u8d4b\u503c\n    data.i = 42;\n    printf(\"data.i = %d\\n\", data.i);\n\n    \/\/ \u7ed9 float \u7c7b\u578b\u6210\u5458\u8d4b\u503c\n    data.f = 3.14;\n    printf(\"data.f = %.2f\\n\", data.f);\n\n    \/\/ \u7ed9\u5b57\u7b26\u4e32\u6210\u5458\u8d4b\u503c\n    snprintf(data.str, sizeof(data.str), \"Hello, Union!\");\n    printf(\"data.str = %s\\n\", data.str);\n\n    \/\/ \u6ce8\u610f\uff1a\u6570\u636e\u8986\u76d6\u95ee\u9898\n    printf(\"\\nAfter assigning string to data.str:\\n\");\n    printf(\"data.i = %d\\n\", data.i);   \/\/ \u6570\u636e\u5df2\u88ab\u8986\u76d6\n    printf(\"data.f = %.2f\\n\", data.f); \/\/ \u6570\u636e\u5df2\u88ab\u8986\u76d6\n\n    return 0;\n}<\/code><\/pre>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>\u8f93\u51fa\uff1a<\/strong><\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>data.i = 42\ndata.f = 3.14\ndata.str = Hello, Union!\n\nAfter assigning string to data.str:\ndata.i = 1737326032\ndata.f = 1.000000<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>4. \u5173\u952e\u70b9<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c<code>data.i<\/code>, <code>data.f<\/code>, <code>data.str<\/code> \u90fd\u5360\u7528\u76f8\u540c\u7684\u5185\u5b58\u5730\u5740\u3002\u5f53\u4e00\u4e2a\u6210\u5458\u8d4b\u503c\u65f6\uff0c\u5b83\u4f1a\u8986\u76d6\u5176\u4ed6\u6210\u5458\u7684\u6570\u636e\u3002<\/li>\n\n\n\n<li>\u5171\u7528\u4f53\u7684\u5927\u5c0f\u4e3a\u6700\u5927\u6210\u5458\u7684\u5927\u5c0f\u3002\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0c<code>str<\/code> \u662f\u6700\u5927\u7684\u6210\u5458\uff0820 \u5b57\u8282\uff09\uff0c\u56e0\u6b64 <code>union Data<\/code> \u7684\u5927\u5c0f\u662f 20 \u5b57\u8282\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>5. \u4f7f\u7528\u5171\u7528\u4f53\u7684\u573a\u666f<\/strong><\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u8282\u7701\u5185\u5b58<\/strong>\uff1a\u5982\u679c\u4f60\u9700\u8981\u591a\u4e2a\u6570\u636e\u7c7b\u578b\uff0c\u4f46\u5728\u4efb\u4f55\u65f6\u523b\u53ea\u4f7f\u7528\u4e00\u4e2a\u6570\u636e\u7c7b\u578b\uff0c\u53ef\u4ee5\u4f7f\u7528\u5171\u7528\u4f53\u6765\u8282\u7701\u5185\u5b58\u3002<\/li>\n\n\n\n<li><strong>\u7c7b\u578b\u8f6c\u6362<\/strong>\uff1a\u5171\u7528\u4f53\u6709\u65f6\u7528\u4e8e\u7c7b\u578b\u8f6c\u6362\uff0c\u7279\u522b\u662f\u5728\u5904\u7406\u4e8c\u8fdb\u5236\u6570\u636e\u6216\u4e0e\u786c\u4ef6\u63a5\u53e3\u65f6\u3002<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>6. \u5171\u7528\u4f53\u4e0e\u7ed3\u6784\u4f53\u7684\u6bd4\u8f83<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u7279\u6027<\/th><th>\u5171\u7528\u4f53(Union)<\/th><th>\u7ed3\u6784\u4f53(Struct)<\/th><\/tr><\/thead><tbody><tr><td>\u5185\u5b58\u5206\u914d<\/td><td>\u6240\u6709\u6210\u5458\u5171\u4eab\u76f8\u540c\u7684\u5185\u5b58\u7a7a\u95f4<\/td><td>\u6bcf\u4e2a\u6210\u5458\u5360\u636e\u72ec\u7acb\u7684\u5185\u5b58\u7a7a\u95f4<\/td><\/tr><tr><td>\u5927\u5c0f<\/td><td>\u7b49\u4e8e\u6700\u5927\u6210\u5458\u7684\u5927\u5c0f<\/td><td>\u6240\u6709\u6210\u5458\u7684\u5927\u5c0f\u4e4b\u548c<\/td><\/tr><tr><td>\u4f7f\u7528\u60c5\u51b5<\/td><td>\u5f53\u9700\u8981\u8282\u7701\u5185\u5b58\uff0c\u4e14\u53ea\u6709\u4e00\u4e2a\u6210\u5458\u5728\u67d0\u4e00\u65f6\u523b\u4f7f\u7528<\/td><td>\u5f53\u9700\u8981\u540c\u65f6\u5b58\u50a8\u591a\u4e2a\u4e0d\u540c\u7c7b\u578b\u7684\u6570\u636e\u65f6<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>7. \u5171\u7528\u4f53\u7684\u5e94\u7528\u573a\u666f<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u786c\u4ef6\u63a5\u53e3<\/strong>\uff1a\u4f8b\u5982\uff0c\u5904\u7406\u4e0d\u540c\u6570\u636e\u7c7b\u578b\u7684\u786c\u4ef6\u5bc4\u5b58\u5668\uff0c\u53ef\u4ee5\u7528\u5171\u7528\u4f53\u6765\u6620\u5c04\u786c\u4ef6\u7684\u4e0d\u540c\u89c6\u56fe\u3002<\/li>\n\n\n\n<li><strong>\u534f\u8bae\u89e3\u6790<\/strong>\uff1a\u5904\u7406\u4e0d\u540c\u683c\u5f0f\u7684\u534f\u8bae\u6570\u636e\u65f6\uff0c\u53ef\u4ee5\u7528\u5171\u7528\u4f53\u6765\u5b58\u50a8\u6570\u636e\u5305\u4e2d\u7684\u4e0d\u540c\u5b57\u6bb5\u3002<\/li>\n\n\n\n<li><strong>\u7c7b\u578b\u8f6c\u6362<\/strong>\uff1a\u901a\u8fc7\u5171\u7528\u4f53\u5171\u4eab\u5185\u5b58\uff0c\u53ef\u4ee5\u5b9e\u73b0\u4ece\u4e00\u79cd\u6570\u636e\u7c7b\u578b\u5230\u53e6\u4e00\u79cd\u6570\u636e\u7c7b\u578b\u7684\u8f6c\u6362\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>8. \u53c2\u8003\u8d44\u6599<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.runoob.com\/cprogramming\/c-union.html\">C\u5171\u7528\u4f53\uff08Union\uff09 &#8211; \u83dc\u9e1f\u6559\u7a0b<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.open-std.org\/jtc1\/sc22\/wg14\/www\/docs\/n2310.pdf\">ISO C Standard &#8211; Union<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 C \u8bed\u8a00\u4e2d\uff0c\u5171\u7528\u4f53\uff08Union\uff09 \u662f\u4e00\u79cd\u6570\u636e\u7ed3\u6784\uff0c\u5b83\u5141\u8bb8\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b\u5b58\u50a8\u5728\u540c\u4e00\u5757\u5185\u5b58\u533a\u57df\u4e2d\u3002\u4e0e\u7ed3\u6784\u4f53\u4e0d\u540c [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":3414,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"class_list":["post-3413","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-c"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3413","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=3413"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3413\/revisions"}],"predecessor-version":[{"id":3415,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/3413\/revisions\/3415"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/3414"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=3413"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=3413"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=3413"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}