MATLAB: I am trying to create a feature vector from the dataset of english character images, the dataset includes total of 62 characters. 26 CAPITAL, 26 small, and 10 numerals. However, the code shows problems with [singleSubFolder, remain] = strtok(remain

Question

% Start with a folder and get a list of all subfolders.
% Finds and prints names of all PNG, JPG, and TIF images in 
% that folder and all of its subfolders.
% Similar to imageSet() function in the Computer Vision System Toolbox: http://www.mathworks.com/help/vision/ref/imageset-class.html
clc;    % Clear the command window.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
% Define a starting folder.
start_path = fullfile(English, '\Fnt');
% Ask user to confirm or change.
topLevelFolder = uigetdir(start_path);
if topLevelFolder == 0
  return;
end
% Get list of all subfolders.
allSubFolders = genpath(topLevelFolder);
% Parse into a cell array.
remain = allSubFolders;
listOfFolderNames = {};
while true
  [singleSubFolder, remain] = strtok(remain, ';');
  if isempty(singleSubFolder)
    break;
  end
  listOfFolderNames = [listOfFolderNames singleSubFolder];
end
numberOfFolders = length(listOfFolderNames) ;
% Process all image files in those folders.
for k = 1 : numberOfFolders
  % Get this folder and print it out.
  thisFolder = listOfFolderNames{k};
  fprintf('Processing folder %s\n', thisFolder);
  % Get PNG files.
  filePattern = sprintf('%s/*.png', thisFolder);
  baseFileNames = dir(filePattern);
  % Now we have a list of all files in this folder.
  if numberOfImageFiles >= 1
    % Go through all those image files.
    for f = 1 : numberOfImageFiles
      fullFileName = fullfile(thisFolder, baseFileNames(f).name);
  fprintf('     Processing image file %s\n', fullFileName);
   end
 else
   fprintf('     Folder %s has no image files in it.\n', thisFolder);
 end
end

Answer 1

Why not replace

remain = allSubFolders;
listOfFolderNames = {};
while true
  [singleSubFolder, remain] = strtok(remain, ';');
  if isempty(singleSubFolder)
    break;
  end
  listOfFolderNames = [listOfFolderNames singleSubFolder];
end

with

listOfFolderNames = regexp(allSubFolders, pathsep, 'split');