unit Unit4;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
type
  TForm4 = class(TForm)
    LabHello: TLabel;
    Button1: TButton;
    Button2: TButton;
    procedure Button2Click(Sender: TObject);
    procedure btShowHello(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form4: TForm4;
implementation
{$R *.dfm}
procedure TForm4.btShowHello(Sender: TObject);
begin
    LabHello.Caption := 'Hello World!';
end;
