c++ - error: 'unordered_set' is not a member of 'std' -

in c++, trying declare unordered_set this:

std::unordered_set<int> k; 

but showing error:

error: 'unordered_set' not member of 'std'

i using g++ (gcc) 5.3.0 on windows using mingw. here things have considered:

1. adding header file #include <unordered_set>
2. upgrading mingw
3. using flag -std=gnu++11. (this not generating executable or error, not sure if doing or not)

how fix , compile code successfully?

use -std=c++11 switch , specify output file.

g++ -std=c++11 your_file.cpp -o your_program