Writing to a CSV/Text File

Hi everyone. I have a bit of code at the moment which is carried out after a series of image processing techniques. At this bit in question, I have my matlab code which then outputs 'results' to the command window of matlab. The results are: a string saying "The experiment is complete/not complete at this stage", the number of black pixels in that image and the time of the picture. The question is, how do I get these results written to a CSV file so that everytime I run this script, the results are written to a file and saved. The plan is to be able to run this GUI on a pc without MATLAB installed so I cant have the results displayed with 'disp' to command window. Here is my code so far:

% --- 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

Any ideas? I have looked online but still haven't found anywhere telling me how to do this. Please explain this as much as possible if that is ok, as I am fairly new to Matlab and "do this" or "do that" won't help me at all. Thankyou very much in advance. The PC I'm on sometimes doesn't let me comment on answers so I apologise in advance.

Ellis