Bubblesort, Delphi, Example (from teacher)

gistfile1.pas

unit bubblesort;

interface

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

type
  TForm1 = class(TForm)
    lb_demo: TListBox;
    bt_add: TButton;
    bt_sort: TButton;
    ed_add: TEdit;
    procedure bt_addClick(Sender: TObject);
    procedure bt_sortClick(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.bt_addClick(Sender: TObject);
var i, anz: integer;
begin
  randomize;
  i   := 0;
  anz := StrToInt(ed_add.Text);
  lb_demo.Clear;
  repeat
    lb_demo.Items.Add(IntToStr(random(1000)));
    i := i +1;
  until i = anz;
end;

procedure TForm1.bt_sortClick(Sender: TObject);
var i,j: integer;
  str: string;
  getauscht: boolean;
begin
  j := lb_demo.Items.count -1; //Bubblesort
  repeat
    i := 0;
    getauscht := false;
    repeat
      if lb_demo.Items[i] > lb_demo.Items[i+1] then
      begin
        getauscht           := true;
        str                 := lb_demo.Items[i];
        lb_demo.Items[i]    := lb_demo.Items[i +1];
        lb_demo.Items[i+1]  := str;
      end;
      i := i+1;
    until i >= j;
    j := j -1;
  until (j = 0) or not getauscht;
end;

end.