Static duck typing in C++

Question

C++ has some sort of duck typing for types given by template parameters. We have no idea what type DUCK1 and DUCK2 will be, but as long as they can

Answer 1

I'd like to omit writing a template parameter list that is repetitive and mostly meaningless (Just imagine what would happen if there are 7 ducks...)

For that you could use variadic templates and do something like the following:

template
void let_them_quack(DUCK &&d) {
  d.quack();
}

template
void let_them_quack(DUCK &&d, Args&& ...args) {
  d.quack();
  let_them_quack(std::forward(args)...);
}

Live Demo