unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Panel1: TPanel;
    Button1: TButton;
    Timer1: TTimer;
    RadioButton1: TRadioButton;
    RadioButton2: TRadioButton;
    RadioButton3: TRadioButton;
    procedure FormShow(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure RadioButton1Click(Sender: TObject);
    procedure RadioButton2Click(Sender: TObject);
    procedure RadioButton3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  Z:integer; // z- кількість символів.
a,b,s:string;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
timer1.Enabled:=true;
edit1.Text:='';
end;

procedure TForm1.FormShow(Sender: TObject);
begin
z:=8;
s:='qwertyuiopasdfghjklzxcvbnm0123456789';
end;

procedure TForm1.RadioButton1Click(Sender: TObject);
begin
z:=8;
end;

procedure TForm1.RadioButton2Click(Sender: TObject);
begin
z:=16;
end;

procedure TForm1.RadioButton3Click(Sender: TObject);
begin
z:=32;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
randomize;
b:=(copy(s,random(length(s)),1));
a:=a+b;
edit1.text:=a;
if (length(edit1.text)=z) and (length(a)=z)   then
begin
timer1.Enabled:=false;
a:='';
end;
end;
end.