The word “functor” comes from category theory, which is a very general, very abstract branch of mathematics. It has been borrowed by designers of functional languages in at least two different ways. In the ML family of languages, a functor is a module that takes one or more other modules as a parameter. It’s considered … Read more
Yes, it is valid. As for making it work with functors as well, the usual solution is something like this instead: template <typename F> void doOperation(F f) { int temp=0; f(temp); std::cout << “Result is ” << temp << std::endl; } which can now be called as either: doOperation(add2); doOperation(add3()); See it live The problem … Read more
A functor is pretty much just a class which defines the operator(). That lets you create objects which “look like” a function: // this is a functor struct add_x { add_x(int val) : x(val) {} // Constructor int operator()(int y) const { return x + y; } private: int x; }; // Now you can … Read more