Help with writing results of a code sequence to a text file

Hi everyone, I have some code that processes images and will produce some results such as a string saying whether or not the experiment is complete, the number of black pixels and the time of the picture. At the moment, I use 'disp' so they appear in my matlab command window, but I want these results to be written to a text file as they are produced. Can anyone help me do this? With commands such as 'fopen' etc? Please explain in dummy terms as I am fairly new to Matlab! Here is my code so far: Thankyou in advance.

% --- Executes on button press in pushbutton3.                    %MAIN!!
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

%The picture interval is entered in editbox2, if not, this error message
%appears.
Interval=str2num(char(get(handles.edit2,'String')));  %Prompt for user to enter camera interval.
if isempty(Interval)
    errordlg('Error, please load pictures to be processed and enter a picture time interval before clicking Run.');
else

%In and out directories chosen by pushbutton1 and pushbutton2
outDir = handles.outDir;

inDir = handles.inDir;

includeSubdirectories = true;

% All extensions that can be read by IMREAD
imreadFormats       = imformats;
supportedExtensions = [imreadFormats.ext];
% Add dicom extensions
supportedExtensions{end+1} = 'dcm';
supportedExtensions{end+1} = 'ima';
supportedExtensions = strcat('.',supportedExtensions);
% Allow the 'no extension' specification of DICOM
supportedExtensions{end+1} = '';

% Create a image data store that can read all these files
imds = datastore(inDir,...
    'IncludeSubfolders', includeSubdirectories,...
    'Type','image',...
    'FileExtensions',supportedExtensions);

h=waitbar(0, 'Please Wait...');
% Process each image using trial_3 (Image Processing toolbox app that let
% me set the HSV thresholds).
for imgInd = 1:numel(imds.Files)
    perc=numel(imds.Files);
    inImageFile  = imds.Files{imgInd};

      % Output has the same sub-directory structure and file extension as
      % input
      outImageFile = strrep(inImageFile, inDir, outDir);

      try
          % Read
          im = imds.readimage(imgInd);
          % Process
          im = trial_3(im);

          % Write
          if(isdicom(inImageFile))
              dicommeta = dicominfo(inImageFile);
              dicomwrite(im, outImageFile, dicommeta, 'CreateMode', 'copy');
          else
              imwrite(im, outImageFile);
          end
          disp(['PASSED:', inImageFile]);

      catch allExceptions
          disp(['FAILED:', inImageFile]);
          disp(getReport(allExceptions,'basic'));
      end
      waitbar(imgInd/perc, h);
      drawnow;
  end
  delete(h);

%Specify the folder where the files (Pictures) live. Chosen by pushbutton2
myFolder=handles.outDir;
%Get a list of all files in the folder with the desired file name pattern.
filePattern=fullfile(myFolder, '*.JPG');
theFiles=dir(filePattern);
caListBoxItems = cell(length(theFiles), 1);
for k=1:length(theFiles)
    baseFileName=theFiles(k).name;
    fullFileName = fullfile(myFolder, baseFileName);
    thisString = fprintf(1, 'Now reading %s', fullFileName);
    fprintf('%s\n', thisString);
    caListBoxItems{k} = thisString;
    OutputFileNames{k} = theFiles(k).name;
    set(handles.listbox2, 'String', OutputFileNames);   %listbox2 will display file names of processed images.
    drawnow;                                % Force immediate screen repaint.
    image=imread(fullFileName);
    white=nnz(image);
    black=(numel(image)-white);
    if black>(numel(image)*0.0193);   %if black pixels is more than 1.93% of pixels in image, experiment complete. Value can be altered.
        disp('The experiment is complete at this stage!')
        fprintf('The number of Black Pixels is:');
        disp(numel(image)-white);
        disp('Time of Picture (Secs): ');
        disp((k-1)*Interval);                        %Here, "Interval" is a variable chosen by user (15 secs, 30 secs etc)
    else
        disp('The experiment is not complete yet.')
        fprintf('The number of Black Pixels is:');
        disp(numel(image)-white);
    end
    guidata(hObject,handles);
end
end

[dpb]

You've pretty much described the process...open an output file with fopen, saving the returned file handle. Use fprintf with that file handle instead of either 1 or implicit as seem to have done and replace disp with fprintf as well. Note you'll need to

1. Use a suitable format string for numeric values, and
2. Remember to write the newline '' to advance to next line

Also, don't forget to fclose(fid) the file before the script/function exits.

[Walter Roberson]

Duplicates http://www.mathworks.com/matlabcentral/answers/274843-writing-to-a-csv-file