Ошибка LNK2019 ссылка на неразрешенный внешний символ "public: virtual __thiscall Base::~Base(void)" (??1Base@@UAE@XZ) в функции "public: virtual __thiscall Money::~Money(void)" (??1Money@@U

#include "Base.h"   
 class Money : public Base    
{    protected:
    int Ruble, kop;    public:
    Money() :Ruble(0), kop(0) {}
    Money(int r, int k) :Ruble(r), kop(k) {}
    void set_valuse(int r, int k)
    {
        Ruble = r; kop = k;
    }
    Money& add(const Money& ob1, const Money& ob2)
    {
        this->Ruble = ob1.Ruble + ob2.Ruble;
        this->kop = ob1.kop + ob2.kop;
        return *this;
    }
    Money& operator+(const Money& ob)
    {
        this->Ruble = Ruble + ob.Ruble;
        this->kop = kop + ob.kop;
        return *this;
    }
    Money& operator-(const Money& ob)
    {
        this->Ruble = Ruble - ob.Ruble;
        this->kop = kop - ob.kop;
        return *this;
    }
    Money& operator*(const Money& ob)
    {
        this->Ruble = Ruble * ob.Ruble;
        this->kop = kop * ob.kop;
        return *this;
    }
    Money& operator/(const Money& ob)
    {
        this->Ruble = Ruble / ob.Ruble;
        this->kop = kop / ob.kop;
        return *this;
    }
    Money& operator=(const Money& ob)
    {
        if (&ob == this)return *this;
        Ruble = ob.Ruble; kop = ob.kop;
        return *this;
    }
    bool operator ==(const Money& ob)
    {
        return (Ruble == ob.Ruble && kop == ob.kop);
    }
    void show()
    {
        cout << "Ruble = " << Ruble << " " << "Kopic = " << kop << endl;
    }
    ~Money() {}    };