View Compilation Error

0_0_36291393_8480.cpp: In function 'int main()':
0_0_36291393_8480.cpp:12:5: error: incomplete type 'std::ios {aka std::basic_ios<char>}' used in nested name specifier
     std::ios::sync_with_stdio(false);
     ^
0_0_36291393_8480.cpp:14:5: error: 'cin' was not declared in this scope
     cin >> T;
     ^
0_0_36291393_8480.cpp:32:9: error: 'cout' was not declared in this scope
         cout << ans << "\n";
         ^