/in/foo.cc: In function 'int main()':
/in/foo.cc:5:13: error: expected unqualified-id before ';' token
  string s,a,;
             ^
/in/foo.cc:12:33: error: no match for 'operator*' (operand types are 'std::__cxx11::string {aka std::__cxx11::basic_string<char>}' and 'int')
       cout<<"快递费为："<<a*5<<"元";
                                ~^~