MCVE for http://stackoverflow.com/q/36507191/547214

printable.cpp

#include <inttypes.h>
#include <stdio.h> // for size_t

class Outputter;
class Printable { public:
	virtual void printTo(Outputter &stream) const = 0;
};

class Outputter { public:
		Outputter() {}
		void printout(const char* c) { printf("%s", c); }
		void printout(const Printable& p) { p.printTo(*this); }
};

Outputter log;

class Printer : public Printable { public:
	Printer(){}
	virtual void printTo(Outputter& pt) const {

		  return pt.printout("I am a printer");
	}
	void print() { /* log.printout(*this); */ }
};

Printer pp;

using namespace std;
int main(int argc, char *argv[]) {
	
	log.printout(pp);
	pp.print();
	
}