how to fix error?

Question

||unrecognized command line option "-std=c++11"|
in codeblocks

Answer 1

Navigate Settings -> Compiler

From the drop-down menu labelled Selected compiler, select the GNU GCC compiler

On the tab-panel below, select Compiler settings -> Compiler flags

From the drop-down menu labelled "Categories", select <All categories>.

Look down the check-box list of compiler options until you see:

Have g++ follow the C++11 ISO C++ language standard [-std=c++11]

If that check-box is unchecked then check it and now try to rebuild.