Mega Code Archive
Generate random numbers with no duplicate values
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procedure Shuffle(var aArray; aItemCount: Integer; aItemSize: Integer);
{ after Julian M Bucknall }
var
Inx: Integer;
RandInx: Integer;
SwapItem: PByteArray;
A: TByteArray absolute aArray;
begin
if (aItemCount > 1) then
begin
GetMem(SwapItem, aItemSize);
try
for Inx := 0 to (aItemCount - 2) do
begin
RandInx := Random(aItemCount - Inx);
Move(A[Inx * aItemSize], SwapItem^, aItemSize);
Move(A[RandInx * aItemSize], A[Inx * aItemSize], aItemSize);
Move(SwapItem^, A[RandInx * aItemSize], aItemSize);
end;
finally
FreeMem(SwapItem, aItemSize);
end;
end;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
a: array[1..10] of Integer;
i: Shortint;
begin
Randomize;
for i := Low(a) to High(a) do a[i] := i;
Shuffle(a, High(a), SizeOf(Integer));
for i := 1 to High(a) - 1 do
ListBox1.Items.Add(IntToStr(a[i]));
end;
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