Menentukan nilai IPK

Soal
Buatlah program yang menerima input nilai(dalam range 0 sampai 100) dan menghasilkan putput berupa keterangan nilai.

IPK	Keterangan
0-15	Nilai E
16-40	Nilai D
41-60	Nilai C
61-80	Nilai B
81-100	Nilai A

Berikut ini tampilan formnya

Dan berikut syntaxnya

unit Utugas1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Label2: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Label3: TLabel;
    Label4: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var x:integer;
begin
  x:=StrToInt(Edit1.Text);
  if x>80 then Edit2.Text:='A'
  else
  if x>60 then Edit2.Text:='B'
  else
  if x>40 then Edit2.Text:='C'
  else
  if x>15 then Edit2.Text:='D'
  else
  Edit2.Text:='E'
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Edit1.Clear;
  Edit2.Clear;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  Application.Terminate;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin

end;

end.