Interface is like docking unit, if your house has a spaceship docking unit, your house can park a spaceship.

class IX
{
	public:
		virtual void Fx1() = 0;
		Virtual void Fx2() = 0;

};

class IY 
{
	virtual void Fx1() = 0;
	virtual void Fx2() = 0;
};

Class CA : public IX, public IY
{
 // Implementing those virtual functions

}