# Programming random digits

Dear friends:

I am a beginner to programming languages and need to program a stimulus for a psychology experiment and as yet haven't worked out the precise coding. The programme consists of single digits from 1-9 that must appear randomly on the screen at 200ms time latencies. The subject is requird to press a button when he/she sees a chain of three odd or three even numbers. otherwise there is no button response.

I have tried doing this by creating a loop and by defining the variables specifically as 'odd' or 'even'. But I can't get Delphi to make them appear as I want. The difficulty is also that I want Delphi to record those trials with 3 odd/even digitd in a row and also record the number of correct responses from the subjects.

Unfortunatly in our lab we have relied heavily on matlab in the past and none of us has in-depth knowledge of Delphi. I would be most grateful if you can help me in anyway or set me on the right track. Maybe such a programme is not even possible in Delphi, in which case I will have to search for another programming language.

Any help will be much appreciated in the form of an acknwoledgement.

Thanks

Peyman

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Commented:
Well, I'm not going to do all your homework for you, but I will point you on your way. Place a timer on your form, a button, and 3 labels. In the OnTimer event of the timer, generate the 3 random numbers and put them in the 3 labels (the caption property, and you'll need to use the IntToStr function). In the OnClick event of the button, check the 3 generated numbers to see whether they're all odd or not, and increment the right/wrong counters appropriately.

Some functions you might use:
Randomize
Rnd
IntToStr
IsOdd

And components:
TTimer
TLabel
TButton
TForm

Geoff M.
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Commented:
Hi,

regards,
odissey1
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Commented:
This should help you out, some!  You may want to prevent the same number from appearing twice in a row, though.

public
{ Public declarations }
X1, X2, X3, CorrectResponses, IncorrectResponses : Integer;
..

procedure TForm1.FormCreate(Sender: TObject);
begin
Randomize;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
X3 := X2;
X2 := X1;
X1 := Random(9) + 1;
Label1.Caption := IntToStr(X1);
Label1.Update;             //paints the new number immediately
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
if (X1 mod 2 = 0) and (X3 mod 2 = 0) and (X3 mod 2 = 0) then
Inc(CorrectResponses)     //All even
else if (X1 mod 2 = 1) and (X3 mod 2 = 1) and (X3 mod 2 = 1) then
Inc(CorrectResponses)     //All odd
else
end;
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Commented:
oops, typo:

procedure TForm1.Button1Click(Sender: TObject);
begin
if (X1 mod 2 = 0) and (X2 mod 2 = 0) and (X3 mod 2 = 0) then
Inc(CorrectResponses)     //All even
else if (X1 mod 2 = 1) and (X2 mod 2 = 1) and (X3 mod 2 = 1) then
Inc(CorrectResponses)     //All odd
else
end;

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Commented:
200ms is pretty doggone fast!

I fail!
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Commented:
Hi roknjohn,

the best I could is 1000 msec!
BTW you example does not handle two first digits that apeared at the beginning. At this moment X2,X3=whatever :).

But, again, this is peanuts.

Sincerely,
odissey1

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Commented:
well, it WAS a homework assignment.  so i left a little work for him to get the "A"  :-)

i recommend disabling the button until 3 numbers have been displayed, i.e. X3<>0.

let me quit now.  <grin>
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Commented:
Hmmmm :-(

;-)
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Author Commented:
Thanks guys for the 'homework'. It's been years since I had any homework:-)
At the moment though, I need to get on with this research as I only have 6 months to show an idea works.

Geoff: I will start from scratch using the functions you reccommend but I only started using Delphi for the first time two weeks ago, so it maybe more cumbersome to begin with.

roknjohn: Thanks for your effort. I still need to spend some time understanding every line.

Cheers to all
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Commented:
Wow.  I guess he really just wanted the EXE. :-)
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Author Commented:
LOL:-)

But seriously, no. I spent all day figuring out what each function does in the codes you guys sent me.  I am getting the hang of this Delphi thing.

There is still a lot for me to do. Delphi displays on the VSG in our lab so I have to figure out how to do that. Also, it doesn't record responses yet and there are no isolated trials.

I'll be busy for a few days yet.
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Commented:
lol, I gave him the compete code. all he had to do was drop three components on a form and its done. And he gave a C grade, to Geoff btw.  At least give Geoff an A!! :-)
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Commented:
Hi roknjohn,

Don't get upset, I send him complete application too... That's the way things go in UK.

regards,
odissey1
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Author Commented:
Hold on to your horses guys.

I wasn't aware how the grading system works here.

Does this mean that I can't grade anyone else?

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