У вашего броузера проблема в совместимости с HTML5
How to run c program in code blocks
Download IDE with compiler-
for Windows XP / Vista / 7 / 8.x / 10:- http://sourceforge.net/projects/codeblocks/files/Binaries/17.12/Windows/codeblocks-17.12mingw-setup.exe
for Mac OS X- http://sourceforge.net/projects/codeblocks/files/Binaries/13.12/MacOS/CodeBlocks-13.12-mac.zip
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Unpaid GuruJi