rem: virtual EWFFILE* clone(void) const { std::cerr << "Not implemented!" << std::endl; return 0; }
add: EWFFILE* EWFFILE::clone(void) const { EWFFILE* target = new EWFFILE(); for(int n = 0; n < number_of_params(); n++) { target->set_parameter(n + 1, get_parameter(n + 1)); } return target; }
context:   virtual EWFFILE* clone(void) const { std::cerr << "Not implemented!" << std::endl; return 0; }