/in/foo.cc: In function 'int main()':
/in/foo.cc:10:2: error: 'vector' was not declared in this scope
  vector<string> user;
  ^~~~~~
/in/foo.cc:10:15: error: expected primary-expression before '>' token
  vector<string> user;
               ^
/in/foo.cc:10:17: error: 'user' was not declared in this scope
  vector<string> user;
                 ^~~~
/in/foo.cc:35:13: error: unable to deduce 'auto&&' from 'user'
  for(auto s:user){
             ^~~~