public HashTable(int size)
        {
            items = new HashItem <T> [size];

            for (int i = 0; i < items.Length; i++)
            {
                items[i] = new HashItem <T>(i);
            }
        }
        public HashTable(IEnumerable <T> iEnume)
        {
            List <T> list = new List <T>();

            list.AddRange(iEnume);


            items = new HashItem <T> [list.Count];

            for (int i = 0; i < items.Length; i++)
            {
                items[i] = new HashItem <T>(i);
            }

            AddRange(iEnume);
        }