[MOJO]

Прошу найти ошибку
на 51 строчке
"Not enough actual parameters."

Код:

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    Button1: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
{
ListBox1.Items.Add('Ðîññèÿ');
ListBox1.Items.Add('Àðìåíèÿ');
ListBox1.Items.Add('Áåëàðóñü');
ListBox1.Items.Add('Êèðãèçèÿ');
ListBox1.Items.Add('Òóðêìåíèñòàí');
}
ListBox1.itemindex:=0;
end;



procedure TForm1.Button1Click(Sender: TObject);
var
k:integer;
dlit, sum:double;
begin

case  ListBox1.Items.Indexof
0: k:=2;
1: k:=3;
2: k:=4;
3: k:=5;
4: k:=6;
end;
begin
dlit:= strtofloat(edit1.Text);
sum:=dlit*k;
end;
ShowMessage('Ñòîèìîñòü ðàçãîâîðà'+floattostr (sum));

end;

end.