Cronômetro

unit Unit1;

    {$mode objfpc}{$H+}

    interface

    uses
      Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls, Buttons,
      ExtCtrls;

    type

      { TForm1 }

      TForm1 = class(TForm)
        Cronometrar: TBitBtn;
        Parar: TBitBtn;
        Edit1: TEdit;
        Timer1: TTimer;
        procedure CronometrarClick(Sender: TObject);
        procedure PararClick(Sender: TObject);
        procedure Timer1Timer(Sender: TObject);
      private

      public

      end;

    var
      Form1: TForm1;
      HoraInicial:TDateTime;

    implementation

    {$R *.lfm}

    { TForm1 }

    procedure TForm1.CronometrarClick(Sender: TObject);
    begin
     HoraInicial := Now;
     Timer1.Enabled := True;
    end;

    procedure TForm1.PararClick(Sender: TObject);
    begin
     HoraInicial := Now;
     Timer1.Enabled := False;
    end;

    procedure TForm1.Timer1Timer(Sender: TObject);
    begin
      Edit1.Text := FormatDateTime('hh:mm:ss',Now-HoraInicial);
    end;

    end.