Generate random numbers without repeating a value: Difference between revisions

=={{header|Delphi}}==

{{works with|Delphi|6.0}}

{{libheader|SysUtils,StdCtrls}}

Creates a "TRandomizer" object which makes it easy to setup and use multiple non repeating randomizers. Since the objects are independent, each one can have different parameters.

<syntaxhighlight lang="Delphi">

{Create randomize object to make it easier to use}

type TRandomizer = class(TObject)

private

FSize: integer;

procedure SetSize(const Value: integer);

protected

procedure Randomize;

public

Numbers: array of Integer;

constructor Create;

property Size: integer read FSize write SetSize;

end;

{ TRandomizer }

constructor TRandomizer.Create;

begin

Size:=20;

end;

procedure TRandomizer.Randomize;

var I,Inx1,Inx2,T: integer;

begin

for I:=1 to 100 do

begin

Inx1:=Random(Length(Numbers));

Inx2:=Random(Length(Numbers));

T:=Numbers[Inx1];

Numbers[Inx1]:=Numbers[Inx2];

Numbers[Inx2]:=T;

end;

end;

procedure TRandomizer.SetSize(const Value: integer);

var I: integer;

begin

if FSize<>Value then

begin

FSize:=Value;

SetLength(Numbers,FSize);

for I:=0 to FSize-1 do Numbers[I]:=I+1;

Randomize;

end;

end;

{------------------------------------------------------------------------------}

procedure ShowRandomNumbers(Memo: TMemo);

var RD: TRandomizer;

var S: string;

var I,J: integer;

begin

RD:=TRandomizer.Create;

try

RD.Size:=20;

for J:=1 to 5 do

begin

RD.Randomize;

S:='[';

for I:=0 to High(RD.Numbers) do

S:=S+Format('%3D',[RD.Numbers[I]]);

S:=S+']';

Memo.Lines.Add(S);

end;

finally RD.Free; end;

end;

</syntaxhighlight>

{{out}}

<pre>

[ 20 12 9 19 2 8 16 14 10 4 11 6 18 5 7 1 17 3 15 13]

[ 7 12 20 13 4 19 8 3 17 5 2 6 9 1 15 11 18 16 10 14]

[ 19 12 7 20 6 16 1 10 13 15 4 2 8 9 3 17 11 18 14 5]

[ 18 13 12 20 8 2 3 10 4 16 19 1 7 5 11 15 9 6 17 14]

[ 17 20 19 3 6 10 12 9 5 16 18 7 8 13 4 15 1 11 14 2]

</pre>