/in/foo.cc: In function 'int main()':
/in/foo.cc:6:5: error: 'cin' was not declared in this scope; did you mean 'sin'?
    6 |     cin>>n;
      |     ^~~
      |     sin
/in/foo.cc:7:5: error: 'cout' was not declared in this scope
    7 |     cout<<pow(2,n);
      |     ^~~~