#ifndef POINTER_TO_UNARY_FUNCTION_REFH
#define POINTER_TO_UNARY_FUNCTION_REFH
#include <functional>   //for pointer_to_unary_function

namespace std {
template <class X, class Y>
class pointer_to_unary_function<X&, Y>: public unary_function<X, Y> {
protected:
	Y (*p)(const X& x);
public:
	pointer_to_unary_function(Y (*initial_p)(const X& x)): p(initial_p) {}
	Y operator()(const X& x) const {return (*p)(x);}
};
}

#endif