虚基类继承时虚函数的重写问题？

#include<string>
#include<ctime>
class Person   // an abstract base class
{
private:
	std::string firstname;
	std::string lastname;
protected:
	virtual void Data();
	virtual void Get();
public:
	Person() : firstname("no firstname"), lastname("no lastname") {}
	Person(const std::string& s1, const std::string& s2)
		: firstname(s1), lastname(s2) {}
	virtual ~Person() {} // pure virtual function

	virtual void Show();
	virtual void Set();
};

class Gunslinger :virtual public Person {
private:
	double gun_time;
	int nickings;
protected:
	virtual void Data();
	virtual void Get();
	double Draw() { return gun_time; }
public:
	Gunslinger() :Person(), gun_time(0.0), nickings(0) {}
	Gunslinger(const std::string& s1, const std::string& s2, double gt, int n)
		:Person(s1, s2), gun_time(gt), nickings(n) {}
	Gunslinger(const Person& p, double gt, int n)
		:Person(p), gun_time(gt), nickings(n) {}
	~Gunslinger() {}
	
	virtual void Show();
	virtual void Set();
};
/*class Card {
private:
	enum { spades, diamonds, clubs, hearts };
public:
	Card()
};*/


class PokerPlayer :virtual public Person {
protected:
	virtual void Data() ;
	virtual void Get();
	int Draw();
public:
	PokerPlayer() :Person() {}
	PokerPlayer(const std::string& s1, const std::string& s2)
		:Person(s1, s2){}
	~PokerPlayer() {}
	virtual void Show();
	virtual void Set();
};



class BadDude : public Gunslinger, public PokerPlayer
{

public:
	BadDude() : Person(), Gunslinger(), PokerPlayer() {}
	BadDude(const std::string& fn, const std::string& ln, int ct = 0, double t = 0)
		: Person(), Gunslinger(fn, ln, ct, t), PokerPlayer() {}
	BadDude(const Person& ps, int ct = 0, double t = 0) 
		: Gunslinger(ps, ct, t), PokerPlayer() {}
	BadDude(const Gunslinger& gs) 
		: Person(gs), PokerPlayer() {}
	BadDude(const PokerPlayer& pp, int ct = 0, double t = 0) 
		: Person(pp), Gunslinger(pp, ct, t) {}
	~BadDude() {}
	void Set();
	void Show();
};

出现E0318,
虚拟函数 函数Person：：Data重写不明确，是什么地方出错了呢。。。