function nback

global inputStatus
inputStatus = 0;

rand('state',sum(100*clock));

% black background figure on which all the information will be presented
mygui.fig = figure('Units','normalized','Position',[0 0 1 1],'Menubar','None','Name','','Numbertitle','Off','Color',[0 0 0]);

dispInstr_NoPress ('nback.bmp');
clf;

probnum=inputdlg('Bitte Probandennummer eingeben');
clf;

%daynum=inputdlg('Bitte Trainingstagnummer eingeben');
%clf;
task='nback';
read=1;
daynum=1;
AllTrainingdays=13;
% current folder
path=pwd;

while read~= -1
    filename = fullfile(path,'datafolder',sprintf('%s%s%d%s%s%s',probnum{1},'D',daynum,'R24',task,'.dat'));
    read=fopen(filename,'rt');
    if read==-1 && daynum==1
        mkdir datafolder;
    elseif read==-1 && daynum>AllTrainingdays
        clf(gcf);
        mygui.inputField = uicontrol('BackgroundColor','k','ForegroundColor','w','Style','text','FontWeight','light','Units','normalized',...
          'Position',[0 0.4 1 .2],'HorizontalAlignment','center','FontSize',40,'string','Alle Trainings sind absolviert, vielen Dank!'); 
        pause(5)
        set(mygui.inputField,'Visible','off','string','');
        close all;
        exit;
    else
        k=9;
    end
    daynum=daynum+1;
end
daynum=daynum-1;

clf;
pause(1)

%-----------------instructions------------------------

dispInstr ('Slide2.bmp');
dispInstr ('Slide2_1.bmp');
dispInstr ('Slide2_2.bmp');
dispInstr ('Slide2_3.bmp');
dispInstr ('Slide2_4.bmp');
dispInstr ('Slide3.bmp');
dispInstr ('Slide4.bmp');
dispInstr ('Slide5.bmp');
clf(gcf);
pause(.5);

%-------------------testing------------------

clf(gcf);
pause(.5)
Test_nback(mygui, probnum, daynum, task, path)

%-------------------data saving--------------
% done in the previous function

dispInstr_NoPress ('Danke.bmp');
close all hidden;