{"id":31726,"date":"2023-01-24T03:53:42","date_gmt":"2023-01-23T22:23:42","guid":{"rendered":"https:\/\/jassweb.com\/solved\/solved-reading-and-writing-a-file-in-byte-array-in-c-c\/"},"modified":"2023-01-24T03:53:42","modified_gmt":"2023-01-23T22:23:42","slug":"solved-reading-and-writing-a-file-in-byte-array-in-c-c","status":"publish","type":"post","link":"https:\/\/jassweb.com\/solved\/solved-reading-and-writing-a-file-in-byte-array-in-c-c\/","title":{"rendered":"[Solved] Reading and writing a file in byte array in C\/C++"},"content":{"rendered":"<p> [ad_1]<br \/>\n<\/p>\n<div id=\"answer-21112882\" class=\"answer js-answer accepted-answer js-accepted-answer\" data-answerid=\"21112882\" data-parentid=\"21112562\" data-score=\"4\" data-position-on-page=\"1\" data-highest-scored=\"1\" data-question-has-accepted-highest-score=\"1\" itemprop=\"acceptedAnswer\" itemscope itemtype=\"https:\/\/schema.org\/Answer\">\n<div class=\"post-layout\">\n<div class=\"votecell post-layout--left\"><\/div>\n<div class=\"answercell post-layout--right\">\n<div class=\"s-prose js-post-body\" itemprop=\"text\">\n<p>Make sure you&#8217;re checking the actual size. Windows has different ways of showing it. <\/p>\n<p>Compare the &#8220;Size&#8221; in bytes (e.g.16666) rather than the &#8220;size on disk&#8221;, which will be rounded up depending on the filesystem.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/jassweb.com\/solved\/wp-content\/uploads\/2023\/01\/Solved-Reading-and-writing-a-file-in-byte-array-in.png\" alt=\"enter image description here\"><\/p>\n<hr>\n<h2> Update<\/h2>\n<p>Your drop box link has this code like this:-<\/p>\n<pre><code>FILE* output = fopen( \"test_output.dat\", \"wb\" );\nfwrite( fileBuf, 1, fileSize, output );\nstd::cout&lt;&lt;\"\\nsaved\";\n\nFILE *file2 = NULL;\nif ((file2 = fopen( \"test_output.dat\", \"rb\")) == NULL)\n    std::cout &lt;&lt; \"Could not open specified file\\n\";\nelse\n    std::cout &lt;&lt; \"File opened successfully\\n\";\n\nlong prev2=ftell(file2);\nfseek(file2, 0L, SEEK_END);\nlong fileSize2 =ftell(file2);\nfseek(file2,prev2,SEEK_SET);\n\nstd::cout &lt;&lt; \"fileSize\" &lt;&lt; fileSize2;\n<\/code><\/pre>\n<p>Here&#8217;s the problem : You don&#8217;t <code>fclose<\/code> the file after writing to it. So when your second <code>fopen<\/code> tries to determine the file size, there&#8217;s still buffered data waiting to be written.  Just add <code>fclose(output);<\/code> after the <code>fwrite<\/code>. If you don&#8217;t do this, the buffered data will only be written at the point when your program exits.<\/p>\n<p>(This is a classic case where the problem was almost impossible to see until you provided a <a rel=\"nofollow noopener\" target=\"_blank\" href=\"http:\/\/sscce.org\/\">SCCCE<\/a> &#8211; which means the 50+ lines of filereader.cpp, not a massive dropbox file&#8230;)<\/p>\n<\/p><\/div>\n<div class=\"mt24\"><\/div>\n<\/div>\n<p>            <span class=\"d-none\" itemprop=\"commentCount\">1<\/span> <\/p><\/div>\n<\/div>\n<p>[ad_2]<\/p>\n<p>solved Reading and writing a file in byte array in C\/C++ <\/p>\n","protected":false},"excerpt":{"rendered":"<p>[ad_1] Make sure you&#8217;re checking the actual size. Windows has different ways of showing it. Compare the &#8220;Size&#8221; in bytes (e.g.16666) rather than the &#8220;size on disk&#8221;, which will be rounded up depending on the filesystem. Update Your drop box link has this code like this:- FILE* output = fopen( &#8220;test_output.dat&#8221;, &#8220;wb&#8221; ); fwrite( fileBuf, &#8230; <a title=\"[Solved] Reading and writing a file in byte array in C\/C++\" class=\"read-more\" href=\"https:\/\/jassweb.com\/solved\/solved-reading-and-writing-a-file-in-byte-array-in-c-c\/\" aria-label=\"More on [Solved] Reading and writing a file in byte array in C\/C++\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[320],"tags":[324],"class_list":["post-31726","post","type-post","status-publish","format-standard","hentry","category-solved","tag-c"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.5 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>[Solved] Reading and writing a file in byte array in C\/C++ - JassWeb<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/jassweb.com\/solved\/solved-reading-and-writing-a-file-in-byte-array-in-c-c\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"[Solved] Reading and writing a file in byte array in C\/C++ - JassWeb\" \/>\n<meta property=\"og:description\" content=\"[ad_1] Make sure you&#8217;re checking the actual size. 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