#include <iostream.h>

class Arg
{
public:
    template <class Type> Arg (Type arg)
    {
        TheArg = (void *) arg;
    }
    template <class Type> void run (void (*f)(Type)) const
    {
        f ((Type) TheArg);
    }
private:
    void *TheArg;
};

void print_int (int i)
{
    cout << i << endl;
}

class A
{
public:
    virtual void run (const Arg & a) = 0;
};

class B : public A
{
public:
    void run (const Arg & a)
    {
        a.run (print_int);
    }
};

int main (void)
{
    A *a = new B (); 
    a->run (Arg (1));
    a->run (Arg (2));
}