C++ виртуальные функции

#include "stdafx.h"
#include <iostream>
#include <conio.h>
 
using namespace std;
 
enum month {jan = 1, feb, mar, apr, may, jun, jul, aug, sep, okt, nov, dek};
class DATE
{
public:
    void Print(char smb); //вывести дату по формату ДД*ММ*ГГ, где * - char smb
    unsigned Valid(unsigned dd, month mm, unsigned yy); //проверка значений ДД.ММ.ГГ
    //static void MyMethod(DATE& MyDate);
    DATE(DATE& MyDate);
    DATE(); //инициализация датой 01.01.0001
    ~DATE();
    unsigned SetDATE(unsigned dd, month mm, unsigned yy); //изменить дату
private:
   unsigned dd;
   month mm;
   unsigned yy;
   char format;
};
 
DATE::DATE(DATE& MyDate) //определение конструктора копии
{
    dd = MyDate.dd;
    mm = MyDate.mm;
    yy = MyDate.yy;
    format = MyDate.format;
    cout << "Copy Constructor...\n";
}
 
DATE::DATE():dd(01) //определение конструктора
{
    //dd = 01;
    mm = jan;
    yy = 0001;
    cout << "Constructor...\n";
}
 
DATE::~DATE() //определение деструктора
{
    cout << "Destructor...\n";
}
 
//void DATE::MyMethod(DATE& MyDate)
//{
    //MyDate.Print(MyDate.format);
    //MyDate.Print(MyDate.format);
//}
 
void DATE::Print(char smb)
{
    cout<<dd<<smb<<mm<<smb<<yy<<"\n";
}
 
unsigned DATE::SetDATE(unsigned dd, month mm, unsigned yy)
{
    this->dd = dd;
    this->mm = mm;
    this->yy = yy;
    return 0;
}
 
unsigned DATE::Valid(unsigned dd, month mm, unsigned yy)
{
    if (dd>31){
        return 0;
    }
    if ((mm==feb) && (dd>28) && (!(yy%4))){
        return 0;
    }
    if ((mm==feb) && (dd>29)){
        return 0;
    }
    return 1;
}
 
int main()
{
    cout << "Input a separator character: ";
    char format = getch();
    cout << format << "\n";
    
    DATE MyDate;
    MyDate.Print(format);
    
    cout << "Example of Date:\n";
    MyDate.SetDATE(18, jan, 1991);
    MyDate.Print(format);
 
    //DATE::MyMethod(MyDate);
 
    if (MyDate.Valid(18, jan, 1991) == 1) cout << "It's OK Date\n";
    else cout << "Date is Wrong";
 
    getch();
    return 0;
}