Быстрая сортировка Хоара

Задание: реализовать алгоритм быстрой сортировки Хоара на Delphi.

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Button1: TButton;
    Button2: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
  const N=40;
var
  Form1: TForm1;
  mas: array[1..N] of integer;
implementation

{$R *.dfm}
procedure sort(l, r: integer);
var
  i,j,temp: integer;
  left: boolean;
begin
left:=true;
if (r-l)>=1 then
begin
 i:=l;
 j:=r;

 while i<>j do
   begin
    if left=true then begin
      if mas[i]<=mas[j] then
        begin
         j:=j-1;
        end
      else
        begin
         temp:=mas[i];
         mas[i]:=mas[j];
         mas[j]:=temp;
         inc(i);
         left:=false;
        end;
      end
      else
      begin
      if mas[i]<=mas[j] then
        begin
         inc(i);
        end
      else
        begin
         temp:=mas[i];
         mas[i]:=mas[j];
         mas[j]:=temp;
         j:=j-1;
         left:=true;
        end;
        end;
   end;
sort(l, i-1);
sort(j+1, r);
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: integer;
begin
randomize;
Label1.Caption:='';
for i:=1 to N do
  begin
   mas[i]:=random(100);
   Label1.Caption:=Label1.Caption+'  '+IntToStr(mas[i]);
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i: integer;
begin
Label2.Caption:='';

sort(1,N);
for i:=1 to N do
  Label2.Caption:=Label2.Caption+'  '+IntToStr(mas[i]);
end;

end.