Simple I/O Manipulators

• Use

unsigned long y;
std::cout << std::hex << y;  // output y in hex notation

• Implementations

namespace std {
  // overload of operator <<() -- done in iostream library
  ostream& operator << (ostream& s, ios_base& F(ios_base&))
                  //  signature of a function - "function pointer"
  {
    return F(s);
  }

  // the manipulator function - clears basefield, then sets hex
  ios_base& hex (ios_base& s)
  {
    s.setf(ios_base::hex, ios_base::basefield);
    return s;
  }
}