gistfile1.hpp

#include <iostream>
using namespace std;

#include <boost/scoped_ptr.hpp>
using namespace boost;

class clonable{
public:
  virtual ~clonable(){}
  virtual clonable *clone() const = 0;
};

class A : public virtual clonable{
public:
  void foo(){
    scoped_ptr<A> p1(dynamic_cast<A*>(this->clone()));
    scoped_ptr<A> p2(dynamic_cast<A*>(this->clone()));

    p1->dat=123;
    p2->dat=456;

    cout<<p1->dat<<" "<<p2->dat<<endl;
  }

  int dat;
};

template <class T>
class cloner : public virtual clonable{
public:
  clonable *clone() const {
    return new T(dynamic_cast<const T&>(*this));
  }
};

class B : public A, cloner<B>{};

int main()
{
  B b;
  b.foo();
  return 0;
}