Ошибка при создании объекта класса

#include <iostream>
using namespace std;
 
class Player;
 
class Weapon
{
public:
    virtual void Shoot(Player& p) = 0;
    
    Weapon()
    {
        cout << "Weapon constructor " << this << endl;
    }
    ~Weapon()
    {
        cout << "Weapon destructor " << this << endl;
    }
    void SetOwner(Player* ptr)
    {
        owner = ptr;
    }
    
    Player* GetOwner()
    {
        return owner;
    }
protected:
    Player* owner;
};
 
class Pistol: public Weapon
{
public:
    Pistol()
    {
        cout << "Pistol constructor " << this << endl;
    }
    ~Pistol()
    {
        cout << "Pistol destructor " << this << endl;
    }
    void Shoot(Player& p) override;
};
 
 
class Player
{
public:
    Player()
    {
        this->health = 100;
        PlayerWP->SetOwner(this);
        cout << "Player constructor " << this << endl;
    }
    ~Player()
    {
        cout << "Player destructor " << this << endl;
    }
    
    void SetWeapon(Weapon *wp)
    {
        PlayerWP = wp;
    }
    
    Weapon* GetWeapon()
    {
        return PlayerWP;
    }
    
private:
    int health;
    Weapon* PlayerWP;
    
    friend void Pistol::Shoot(Player& p);
};
 
int main()
{
    cout << "create pistol" << endl;
    Pistol Colt;
    cout << "create players" << endl;
    Player fP, sP;
    cout << "set weapon" << endl;
    fP.SetWeapon(&Colt);
    cout << "get and shoot" << endl;
    fP.GetWeapon()->Shoot(sP);
    cout << "exit" << endl;
    return 0;
}
 
void Pistol::Shoot(Player& p)
{
    cout << "Bang!" << endl;
}

class Player
{
public:
    Player() : health(100), PlayerWP(0)
    {
        cout << "Player constructor " << this << endl;
    }
 
    void SetWeapon(Weapon *wp)
    {
        PlayerWP = wp;
        PlayerWP->SetOwner(this); // !
    }
 
///... остальное ...
};