tYSR20

346Part V: Optional FeaturesI haven’t created the hierarchy shown in Figure 26-2 after all. The inheritancehierarchy I have actually created is the one shown in Figure 26-4.FurnitureweightFurnitureweightBedSofasleep( )watchTV( )Figure 26-4:Actualresult of myfirst attempt.foldOut( )SleeperSofaThe MultipleInheritanceFactoring program demonstrates this duplication ofthe base class. Section 2 specifies exactly which weight object by recastingthe pointer SleeperSofa first to a Sofa* and then to a Furniture*.But SleeperSofa containing two Furniture objects is nonsense.SleeperSofa needs only one copy of Furniture. I want SleeperSofato inherit only one copy of Furniture, and I want Bed and Sofa to sharethat one copy. C++ calls this virtual inheritance because it uses the virtualkeyword.I hate this overloading of the term virtual because virtual inheritance hasnothing to do with virtual functions.Armed with this new knowledge, I return to class SleeperSofa and implementit as follows://// VirtualInheritance - using virtual inheritance the// Bed and Sofa classes can share a common base//#include