{"id":14673,"date":"2024-03-15T09:43:27","date_gmt":"2024-03-15T09:43:27","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/what-is-the-method-for-reading-a-file-and-outputting-its-content-in-the-c-language\/"},"modified":"2025-08-06T11:54:20","modified_gmt":"2025-08-06T11:54:20","slug":"what-is-the-method-for-reading-a-file-and-outputting-its-content-in-the-c-language","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/what-is-the-method-for-reading-a-file-and-outputting-its-content-in-the-c-language\/","title":{"rendered":"How to Read a File in C"},"content":{"rendered":"<p>In C programming language, you can use the following method to read file contents and output them:<\/p>\n<ol>\n<li>open a file<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code>FILE *file = fopen(<span class=\"hljs-string\">\"filename.txt\"<\/span>, <span class=\"hljs-string\">\"r\"<\/span>);\r\n<\/code><\/pre>\n<ol>\n<li>Check if the file has been successfully opened: Use a file pointer to perform a null check to ensure that the file has been opened successfully. For example:<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-keyword\">if<\/span> (file == <span class=\"hljs-literal\">NULL<\/span>) {\r\n    <span class=\"hljs-built_in\">printf<\/span>(<span class=\"hljs-string\">\"\u65e0\u6cd5\u6253\u5f00\u6587\u4ef6\"<\/span>);\r\n    <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-number\">1<\/span>;\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>read input from a file<\/li>\n<li>Reads a line from the specified file.<\/li>\n<li>use the printf function<\/li>\n<\/ol>\n<ol>\n<li>Read line by line using the fscanf() function.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-type\">char<\/span> line[<span class=\"hljs-number\">100<\/span>];\r\n<span class=\"hljs-keyword\">while<\/span> (<span class=\"hljs-built_in\">fscanf<\/span>(file, <span class=\"hljs-string\">\"%s\"<\/span>, line) != EOF) {\r\n    <span class=\"hljs-built_in\">printf<\/span>(<span class=\"hljs-string\">\"%s\\n\"<\/span>, line);\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>Read line by line using the fgets() function.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code><span class=\"hljs-type\">char<\/span> line[<span class=\"hljs-number\">100<\/span>];\r\n<span class=\"hljs-keyword\">while<\/span> (fgets(line, <span class=\"hljs-keyword\">sizeof<\/span>(line), file) != <span class=\"hljs-literal\">NULL<\/span>) {\r\n    <span class=\"hljs-built_in\">printf<\/span>(<span class=\"hljs-string\">\"%s\"<\/span>, line);\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>Close the file.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code>fclose(file);\r\n<\/code><\/pre>\n<p>Complete code example:<\/p>\n<pre class=\"post-pre\"><code><span class=\"hljs-meta\">#<span class=\"hljs-keyword\">include<\/span> <span class=\"hljs-string\">&lt;stdio.h&gt;<\/span><\/span>\r\n\r\n<span class=\"hljs-type\">int<\/span> <span class=\"hljs-title function_\">main<\/span><span class=\"hljs-params\">()<\/span> {\r\n    FILE *file = fopen(<span class=\"hljs-string\">\"filename.txt\"<\/span>, <span class=\"hljs-string\">\"r\"<\/span>);\r\n    <span class=\"hljs-keyword\">if<\/span> (file == <span class=\"hljs-literal\">NULL<\/span>) {\r\n        <span class=\"hljs-built_in\">printf<\/span>(<span class=\"hljs-string\">\"\u65e0\u6cd5\u6253\u5f00\u6587\u4ef6\"<\/span>);\r\n        <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-number\">1<\/span>;\r\n    }\r\n\r\n    <span class=\"hljs-type\">char<\/span> line[<span class=\"hljs-number\">100<\/span>];\r\n    <span class=\"hljs-keyword\">while<\/span> (fgets(line, <span class=\"hljs-keyword\">sizeof<\/span>(line), file) != <span class=\"hljs-literal\">NULL<\/span>) {\r\n        <span class=\"hljs-built_in\">printf<\/span>(<span class=\"hljs-string\">\"%s\"<\/span>, line);\r\n    }\r\n\r\n    fclose(file);\r\n    <span class=\"hljs-keyword\">return<\/span> <span class=\"hljs-number\">0<\/span>;\r\n}\r\n<\/code><\/pre>\n<p>Please ensure that the file exists and has the correct path before opening it. Additionally, the content read from the file will depend on its format and content type.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In C programming language, you can use the following method to read file contents and output them: open a file FILE *file = fopen(&#8220;filename.txt&#8221;, &#8220;r&#8221;); Check if the file has been successfully opened: Use a file pointer to perform a null check to ensure that the file has been opened successfully. For example: if (file [&hellip;]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[381,450,890,380,11262],"class_list":["post-14673","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-c-programming","tag-c-tutorial","tag-file-handling","tag-file-i-o","tag-fopen"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to Read a File in C - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Learn to read file contents in C with step-by-step examples. fopen, fscanf, and error handling explained simply.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/what-is-the-method-for-reading-a-file-and-outputting-its-content-in-the-c-language\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"How to Read a File in C\" \/>\n<meta property=\"og:description\" content=\"Learn to read file contents in C with step-by-step examples. fopen, fscanf, and error handling explained simply.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/what-is-the-method-for-reading-a-file-and-outputting-its-content-in-the-c-language\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - 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