29 The Power of Inheritance and Polymorphism

Inheritance and Polymorphism 1032DungeonItemownslink to Dungeon, pointcoord, display symboldoesdraws itself, erasesitself, reads data fromfile, reports where it isCollectableowns3 integer value fieldsdoesreads extra data,reports valuesActiveItemownshealth & strengthattributesdoesreads extra data"runs" (define in subclass)gets hitreports if still "alive"movesPlayerMonsterowns"manna", wealth attributes,movecount, links to windowsused to display statusdoesreads extra datagets user command, takescollectables, attacksmonsters, interpretsmovement & magic commandsowns(nothing extra)does"runs" using"Can Attack", "Attack","Can Detect", "Advance","NormalMove"Ghost Wanderer PatrolSubclasses of Monster ownunique data (patrol "route", wanderer recordof last move)doessubstitute specialized NormalMove(), Advance(),functions; read any extra data params.Figure 29.4DungeonItem class hierarchy.class Dungeon {public:Dungeon();~Dungeon();void Load(const char filename[]);int Run();int Accessible(Pt p) const;Window *Display();Player *Human();intValidPoint(Pt p) const;Monster *M_at_Pt(Pt p);Collectable *PI_at_Pt(Pt p);void RemoveProp(Collectable *pi);void RemoveM(Monster *m);