public boolean isOccupied(String old_pos,String new_pos)
	{
		String convert_old_pos = CUtil.pos_Finder(old_pos);
		String convert_new_pos = CUtil.pos_Finder(new_pos);		
		int nfile = Integer.parseInt(convert_new_pos.substring(0,1));
		int nrank = Integer.parseInt(convert_new_pos.substring(1));
		int ofile = Integer.parseInt(convert_old_pos.substring(0,1));
		int orank = Integer.parseInt(convert_old_pos.substring(1));
		if(board[nfile][nrank].isEmpty())
		{
			return false;
		}
		if(!board[nfile][nrank].getPiece().getColor().equals(board[ofile][orank].getPiece().getColor()))//compares colors of two pieces
		{
			return false;
		}
		return true;
	}