29 The Power of Inheritance and Polymorphism

Inheritance and Polymorphism 1060}y += dy;if(!fD->ValidPoint(Pt(x,y))) return;Monster* m = fD->M_at_Pt(Pt(x,y));if(m != NULL) {m->GetHit(power);if(!m->Alive())fD->RemoveM(m);}power /= 2;}MonsterThe constructor and destructor functions of class Monster both have empty bodiesfor there is no work to be done; the constructor passes its arguments back to theconstructor of its parent class (ActiveItem):Monster::Monster(Dungeon *d, char sym) : ActiveItem(d, sym){}Function Monster::Run() was defined earlier. The default implementations ofthe auxiliary functions are:int Monster::CanAttack(){Player *p = fD->Human();Pt target = p->Where();return fPos.Adjacent(target);}void Monster::Attack(){Player *p = fD->Human();p->GetHit(fStrength);}int Monster::CanDetect() { return 0; }void Monster::Advance() { }GhostThe Ghost::CanDetect() function uses the Pt::Distance() member functionto determine the distance to the Player (this function just takes the normalEuclidean distance between two points, rounded up to the next integral value).int Ghost::CanDetect(){Player *p = fD->Human();