namespace utility
{
    public class DateImpl: Date
    {
        private int iYear;
        private int iMonth;
        private int iDay;
        public DateImpl(int pYear, int pMonth, int pDay)
        {
            iYear  = pYear;  iMonth = pMonth;  iDay = pDay;
        }
        public int Year
        {
            get { return iYear;   } 
            set { iYear = value;  }
        }
        public int Month
        {
            get { return iMonth;  }
            set { iMonth = value; }
        }
        public int Day
        {
            get { return iDay;    }
            set { iDay = value;   }
        }
        public override bool Equals(object pObject)
        {
            DateImpl tDateImpl = (DateImpl)pObject;
            return this==tDateImpl;
        }
        public static bool operator ==(DateImpl pLeft, DateImpl pRight)
        {
            return pLeft.iYear ==pRight.iYear  &&
                   pLeft.iMonth==pRight.iMonth &&
                   pLeft.iDay  ==pRight.iDay;                        
        }
        public static bool operator !=(DateImpl pLeft, DateImpl pRight)
        {
            return ! (pLeft==pRight);
        }
        public override int GetHashCode()
        {
            return 0;
        }
        public int CompareTo(object pObject)
        {
            DateImpl tDateImpl = (DateImpl)pObject;
            int tResult = iYear - tDateImpl.iYear;
            if (tResult==0)
            {
                tResult = iMonth - tDateImpl.iMonth;
                if (tResult==0)
                {
                    tResult = iDay - tDateImpl.iDay;
                }
            }
            return tResult;
        }
        public override string ToString()
        {
            return iYear + "-" + iMonth/10 + iMonth%10 
                         + "-" +   iDay/10 +   iDay%10;
        }
    }
}