SysUtils.IsLeapYear ();
DateUtils.IsInLeapYear ();


unit Unit1;

interface

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

type 
  TForm1 =class (TForm)
    procedure FormCreate (Sender: TObject);
  end ;

var
  Form1: TForm1;

implementation

{$ R * .dfm}

uses DateUtils;

procedure TForm1.FormCreate (Sender: TObject);
var
  b: Boolean;
begin 
  b: = IsLeapYear (2009); // False
  b: = IsLeapYear (2012); // True

  b: = IsInLeapYear (StrToDateTime ('2009-1-1')); // False
  b: = IsInLeapYear (StrToDateTime ('2012-1-1')); // True

// ShowMessage (BoolToStr (b, True));
end ;

end .