View Compilation Error

0_0_28103912_26950.cpp:37:5: error: 'mutex' does not name a type
     mutex my_mutex;
     ^
0_0_28103912_26950.cpp: In function 'int main()':
0_0_28103912_26950.cpp:54:5: error: 'thread' was not declared in this scope
     thread t2(&Game::output, &g);
     ^
0_0_28103912_26950.cpp:55:12: error: expected ';' before 't1'
     thread t1(&Game::input, &g);
            ^
0_0_28103912_26950.cpp:57:5: error: 't1' was not declared in this scope
     t1.join();
     ^
0_0_28103912_26950.cpp:58:5: error: 't2' was not declared in this scope
     t2.join();
     ^