Apply functions belonging to other classes through variadic templates

Question

Say I have three classes, ClassA, ClassB, and ClassC. And all three of these classes have a function called updateValue(int).

Answer 1

From your current interface, you might do something like:

class Controller
{
 public:
    template <class...Classes>
    Controller(Classes&... classes)
    {
        mF = [&](int val) { (classes.updateValue(val), ...); }; // Fold expression from C++17
    }

    void setValues(int val)
    {
        mF(val);
    }
    private:
        std::function<void(int)> mF;
    };