The random function ...
lazarus / 9-Editor

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GoDxNero · 2009-10-17 11:06

Its about 2 dice's. a is the eyes of dice1 and b is the eyes of dice2.
rt1 is the roltime of dice1 and its random. So if roltime1 = 0 then a
will stop with randomize, same goes for b.
cd = countdown . However I always got the same result each time I
close the game and restart it. What is wrong ?

procedure TForm1.PlayClick(Sender: TObject);
begin
  roll := 0;
  cd := 0;
  rt1 := 2 + random(5);
  rt2 := 2 + random(5);
  r1 := rt1;
  r2 := rt2;
  Label3.Caption := IntToStr(r1);
  Label4.Caption := IntToStr(r2);
  Timer1.Enabled := True;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  roll := roll + 0.0157;
  if roll < rt1
  then a := 1 + random(6)
  else a := a;
  if roll < rt2
  then b := 1 + random(6)
  else b := b;
  Label1.Caption := IntToStr(a);
  Label2.Caption := IntToStr(b);
  cd := cd + 0.0157;
  if cd > 1 then
  begin
    cd := 0;
    if r1 > 0 then
    r1 := r1 - 1;
    if r2 > 0 then
    r2 := r2 - 1;
  end;
  Label4.Caption := IntToStr(r1);
  Label4.Caption := IntToStr(r2);
  if (r1 = 0) and (r2 = 0) then
  Timer1.Enabled := False;
end;

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Martin_fr · 2009-10-17 11:32

do you call randomize ?

You should call it once when your app starts.

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GoDxNero · 2009-10-17 12:08

Oh , didnt know about that   .

I just read http://www.delphibasics.co.uk/RTL.asp?Name=Randomize about
randomize

But I still dont get at all how it works .
Do I have to always use the ' i ' and the ' loop ' or if I just put
'randomize' before any random function then it will works ?

Like this ?

procedure TForm1.PlayClick(Sender: TObject);
begin
  randomize;
  roll := 0;
  cd := 0;
  rt1 := 2 + random(5);
  rt2 := 2 + random(5);
  r1 := rt1;
  r2 := rt2;
  Label3.Caption := IntToStr(r1);
  Label4.Caption := IntToStr(r2);
  Timer1.Enabled := True;
end;

will it work in the Timer too ?

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  randomize;
  roll := roll + 0.0157;
  if roll < rt1
  then a := 1 + random(6)
  else a := a;
  if roll < rt2
  then b := 1 + random(6)
  else b := b;
  Label1.Caption := IntToStr(a);
  Label2.Caption := IntToStr(b);
  cd := cd + 0.0157;
  if cd > 1 then
  begin
    cd := 0;
    if r1 > 0 then
    r1 := r1 - 1;
    if r2 > 0 then
    r2 := r2 - 1;
  end;
  Label4.Caption := IntToStr(r1);
  Label4.Caption := IntToStr(r2);
  if (r1 = 0) and (r2 = 0) then
  Timer1.Enabled := False;
end;

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Leledumbo · 2009-10-19 05:52

You just need to call it once (at OnCreate for example), and it will
hold throughout the program.

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GoDxNero · 2009-10-23 21:09

ok . btw I have one more question .

If I want to random 3 numbers ( a, b, c ) .

a := 1 + random(6);
b := 1 + random(6);
c := 1 + random(6);

But I dont want them to be the same.
So if a = 3 then b can be any number from 1~6 except 3 .
and if b = 4 then c can be any number from 1~6 except 3 and 4.

Is there a simple way to write such code with even more variable ?

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eny · 2009-10-23 21:17

Create an integer list and put all valid numbers in the list (in your
case 1..6).
Generate a random number that is the index in the list (0..5 if the
list indexes are zero-based).
Extract the number at that position and generate the next index
number. Which of course will be an index number from 0..4.
Again extract the chosen number from the list and generate the next
index number (0..3).
etc. etc.

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GoDxNero · 2009-10-23 21:20

could you please give me a piek at this code ? I dont understand about
the index part, how to write it... srry for being noob

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theo · 2009-10-23 21:58

One possible way:

Code: [Select]function RandomSort(Item1, item2: Pointer): integer;
begin
 Result := -1 + Random(3);
end;

procedure TForm1.Button1Click(Sender: TObject);
const LowNumber=1;
const HighNumber=6;
const CountNumbers=3;
var L:TList;
i, nextnum:integer;
begin
  Memo1.Lines.Clear;
  L:=TList.create;
  for i:=LowNumber to HighNumber do L.Add(Pointer(i));
  Randomize;
  L.Sort(@RandomSort);
  for i:=0 to CountNumbers-1 do
  begin
    nextnum:=PtrInt(L[i]);
    Memo1.Lines.Add(IntToStr(nextnum));
  end;
  L.free;
end;

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Martin_fr · 2009-10-23 22:19

Quote from: GoDxNero on October 23, 2009, 11:09:06 pmIf I want to
random 3 numbers ( a, b, c ) .

a := 1 + random(6);
b := 1 + random(6);
c := 1 + random(6);

But I dont want them to be the same.
So if a = 3 then b can be any number from 1~6 except 3 .

a := 1 + random(6);

b := 1 + random(5);
if b >= a then inc(b);

c := 1 + random(4);
if c >= min(a,b) then inc(c);
if c >= max(a,b) then inc(c);

min and max are from the "Math" unit


If you need more than 3 diff numbers it will be more complex, and you
better go with theo's code

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GoDxNero · 2009-10-23 22:21

I will try to bash my brain out with Theo code xD

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davesimplewear · 2009-10-24 08:00

Library RxNew contains rxDice, why not checkout their code, why
reinvent the wheel?

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brunello · 2009-10-24 08:39

One possible way:

procedure TForm1.Button1Click(Sender: TObject);
const LowNumber=1;
const HighNumber=6;
const CountNumbers=3;
var
  i, n: integer;
  s: string;
  lista: TStringList;
begin
  lista := TStringList.Create;
  for i := LowNumber to HighNumber do
    lista.Add(IntToStr(i));
  s := '';
  randomize();
  for i := 0 to (CountNumbers - 1) do
    begin
      n := random(HighNumber - i);
      s := s + ' ' + lista[n];
      lista.Delete(n);
    end;
  lista.Free;
  ListBox1.Items.Add(s);
end;