unit Ex1Main;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    StatusBar1: TStatusBar;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  a,b:Integer;
begin
  a:=20;b:=10;
  if a>b then
    Messagebox(Handle,'a>b','info',MB_OK);
end;

end.