Psuedo-Events

// ConsoleApplication8.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
    #include <string>
    #include <iostream>
    #include <functional>
    #include <vector>
    using namespace std;

    template <typename ...Args>

    //Simplification for readability
    using delegate = std::function<void(Args...)>;

    template <typename ...Args>
    //Signal class -- holds vector of functions.
    class signal {
    private:
        using fn_t = delegate<Args...>;
        std::vector<fn_t> observers;

    public:
        void connect(fn_t f) {
            observers.push_back(f);
        }

        void disconnect(fn_t f)
        {
            // No code yet.
        }

        void operator ()(Args... a) {
            for (auto i : observers)
                i(a...);
        }
    };

    // Button to send Click event through Signal Update.
    struct button {
        signal<int, int> update;

        void click(int x, int y) {
            update(x, y);
        }
    };

    // Label with PrintNum
    struct label {
        std::string text;

        void PrintNum(int x, int y) {
            std::cout <<  x << y << std::endl;
        }
    };

    int main() {
        using namespace std::placeholders;

        label label1;
        label label2;

        button button1;

        // Connect buttons, testing two different methods.
        button1.update.connect(std::bind(&label::PrintNum, std::ref(label1), _1, _2));
        button1.update.connect([&](int x, int y) { label1.PrintNum(x, y); });

        //Click event, expecting output '23'
        button1.click(2, 3);


        system("pause");
        return 0;
    };