repos/ConsoleApplication5/ConsoleApplication5/ConsoleApplication5.cpp

#include <functional>
#include <vector>
#include <map>
#include <iostream>

template <class... Params>
class Event
{
public:

    template <class T>
    using MemberPtr = void (T::*)(Params...);

    using Callback = std::function<void(Params...)>;

    template <class T>
    void
        Subscribe(T* t, MemberPtr<T> m)
    {
        const auto lambda = [=](Params&&... params) { (t->*m)(std::forward<Params>(params)...); };
        Addcallback(lambda);
    }

    void
        Notify(Params&&... params) const
    {
        for (const auto& callback : mCallbacks)
        {
            callback(std::forward<Params>(params)...);
        }
    }

private:

    void
        Addcallback(Callback callback)
    {
        mCallbacks.emplace_back(callback);
    }

    std::vector<Callback> mCallbacks;
    std::map<int, Callback> mCall_map; 
};

struct EventListener
{
    void
        eventListenerCallback(int i)
    {
        std::cout << "Received " << i << std::endl;
    }
};

struct DoublingListener
{
    void
        eventListenerCallback(int i, int y)
    {
        std::cout << "Double of received value " << i * 2 << std::endl;
    }
};

int
main()
{
    Event<int> event;
    Event<int,int> eventD;

    EventListener listener;
    DoublingListener doublingListener;

    event.Subscribe(&listener, &EventListener::eventListenerCallback);
    eventD.Subscribe(&doublingListener, &DoublingListener::eventListenerCallback);
    event.Notify(1337);

    return 0;
}