Base.cpp

#ifndef BASECLASS_H
#define BASECLASS_H

#include <string>
#include <iostream>

template <class Derived>
class BaseClass
{
public:
	BaseClass(int i, const std::string& s): ii(i), ss(s) { }
	// virtual ~BaseClass() { }

	int getII() const { return ii; }
	std::string getSS() const { return ss; }

	// Returns a clone of the derived 
	Derived* clone() const { return new Derived(static_cast<const Derived&>(*this)); }

	// print() is now statically polymorphic by calling the statically implemented derivedPrint()
	void print(std::ostream& out) const { return static_cast<Derived&>(*this).derivedPrint(out); }
private:
	// default handler for print
	void derivedPrint(std::ostream& out) const {
		out << "printing from base class!" << std::endl;
	}

	int ii;
	std::string ss;
};

#endif // BASECLASS_H

DerivedClass2.cpp

#include "BaseClass.h"


class DerivedClass2 : public BaseClass<DerivedClass2>
{
public:
	DerivedClass2(int i, const std::string& s, double d): BaseClass(i, s), dd(d) { }
	// virtual ~DerivedClass2() { }

	double getDD() const { return dd; }
private:
	void derivedPrint(std::ostream& out) const {
		out << "printing from DerivedClass2" << std::endl;
	}

	double dd;
};