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

We only need to write one version of the function:

#include 

template
void let_them_quack(Quackers&& ...quackers) {
  using expand = int[];

  void(expand { 0, (std::forward(quackers).quack(), 0)... });
}

struct Duck {
  void quack() {}
};

int main()
{
  Duck a, b, c;
  let_them_quack(a, b, c, Duck());
}