/in/foo.cc: In function 'int main()':
/in/foo.cc:39:20: error: expected unqualified-id before '<<' token
  std::ostringstream<<fixed<<setprecision(2)<<bill;
                    ^~
/in/foo.cc:40:31: error: expected primary-expression before '.' token
  string ans=std::ostringstream.str();
                               ^