trampoline.cpp

#include <iostream>

using namespace std;

class Bounce{
public:
    virtual ~Bounce(){};
};

class Num : public Bounce{
public:
    int value;
    Num(int n) {
        this->value=n;
    }
    ~Num(){};
};
class Closure : public Bounce{
public:
    Bounce* (*fun)(int);
    int arg;
    Closure(Bounce*(*f)(int), int n):fun(f),arg(n){};
    Bounce* operator()()
    {
        return (*fun)(arg);
    }
    ~Closure(){};
};

int trampoline(Bounce* b)
{
    while (Closure* f=dynamic_cast<Closure*>(b)){
        b = (*f)();
        delete f;
    }   
    int r=((Num*)b)->value;
    delete (Num*)b;
    return r;
}

Bounce* loop(int n)
{
    int x[10];
    if (n == 12345678) {
        return new Num(n);
    }
    if(!(n%1000)) {
        cout << ".";
        return new Closure(loop,++n);
    }
    else return loop(++n);
}

int main()
{
    int t = trampoline(loop(0));
    cout << endl;
    cout << t << endl;
}