#include <iostream>
#include <functional>

class Item;
typedef  std::function<void(int)> Action;

class Item 
{
public:
    explicit Item(int y) : y_(y) {}
    void do_action(int x) { action_(x); }
    Action action_;
    int y_;
};

int main()
{
    Item it1(3);
    Action a = [&it1](int x){ std::cout << "Wert x:  " << x << " Wert y: " << it1.y_ << "\n"; };
    it1.action_ = a;
    it1.do_action(5);
}