ReaderIface.hpp
===============
class ReaderIface {
public:
    // All existing code from ReaderIface

	virtual const char* const* getExt() = 0;
};


WriteerIface.hpp
===============
class WriterIface {
public:
    // All existing code from WriterIface

	virtual const char* const* getExt() = 0;
};


IoVtk.hpp
=========
class IoVtk {
public:
	IoVtk();

	virtual ~IoVtk();

	static const char* const* getExtS() { return IoVtk::sfx; }
	static const char* getDescr() { return IoVtk::desc; }
	static const char* getFormat() { return IoVtk::format; }
	const char* const* getExt();

private:

	static const char* sfx[];
	static const char* desc;
	static const char* format;
};


IoVtk.cpp
=========
#include "IoVtk.h"

const char* IoVtk::sfx[] = { "vtk", 0 };
const char* IoVtk::desc = "Kitware VTK";
const char* IoVtk::format = "VTK";
const char* const* IoVtk::getExt() { return IoVtk::sfx; }


ReadVtk.hpp
===========
class ReadVtk: public ReaderIface, public IoVtk {
public:
    // All existing code from ReadVtk

	const char* const* getExt() { return this->IoVtk::getExt(); }
};


ReadVtk.cpp
===========
No changes


WriteVtk.hpp
============
class WriteVtk: public WriterIface, public IoVtk {
public:
    // All existing code from WriteVtk

	const char* const* getExt() { return this->IoVtk::getExt(); }
};


WriteVtk.cpp
============
No changes