#include <iostream>
#include <cstdlib>
using namespace std;

class base {
public:
	base() {f();}           //always calls base::f
	virtual ~base() {f();}  //would also call base::f if we ever got this far

	virtual void f() const = 0;
	void g() const {f();}   //doesn't necessarily call base::f
};

class derived: public base {
public:
	derived(): base() {}
	void f() const {cout << "derived::f\n";}
};

int main()
{
	derived d;
	return EXIT_SUCCESS;
}