/in/foo.cc: In function 'int main()':
/in/foo.cc:5:5: error: 'cin' was not declared in this scope
     cin>>n;
     ^~~
/in/foo.cc:21:5: error: 'cout' was not declared in this scope
     cout<<c<<endl;
     ^~~~
/in/foo.cc:21:14: error: 'endl' was not declared in this scope
     cout<<c<<endl;
              ^~~~