code: public void removeAllElements()
    {
  
      if (null == m_map)
        return;
  
      for (int i = 0; i < m_firstFree; i++)
      {
        m_map[i] = DTM.NULL;
      }
  
      m_firstFree = 0;
    }
docs: Inserts the specified node in this vector at the specified index.
  Each component in this vector with an index greater or equal to
  the specified index is shifted upward to have an index one greater
  than the value it had previously.