29 The Power of Inheritance and Polymorphism

Implementation: DungeonItems 1061}int range = fPos.Distance(p->Where());return (range < 7);The Advance() function determines the change in x, y coords that will bringthe Ghost closer to the Player.void Ghost::Advance(){Player *p = fD->Human();Pt p1 = p->Where();int dx, dy;dx = dy = 0;if(p1.X() > fPos.X()) dx = 1;elseif(p1.X() < fPos.X()) dx = -1;if(p1.Y() > fPos.Y()) dy = 1;elseif(p1.Y() < fPos.Y()) dy = -1;}Move(Pt(fPos.X() + dx, fPos.Y() + dy));WandererThe Wanderer::CanDetect() function uses the Dungeon::ClearLineOfSight()member function to determine whether the Player object is visible. This functioncall also fills in the array fPath with the points that will have to be crossed.int Wanderer::CanDetect(){Player *p = fD->Human();returnfD->ClearLineOfSight(fPos, p->Where(), 10, fPath);}The Advance() function moves one step along the path:void Wanderer::Advance(){Move(fPath[0]);}The NormalMove() function tries moving in the same direction as before.Directions are held by storing the delta-x and delta-y values in fLastX and fLastYdata members (initialized to zero in the constructor). If movement in that generaldirection is blocked, a new direction is picked randomly.void Wanderer::NormalMove(){int x = fPos.X();int y = fPos.Y();