Example Error For

procedure TForm1.FormDblClick(Sender: TObject);
var
  K1: Integer;
  K2: Double;
  Sum: Double;
begin
  Sum := 0;
  for K1 := 0 to 9 do
    Sum := Sum   K1;
  ShowMessage(FloatToStr(Sum));
  Sum := 0;
  for K2 := 0 to 9 do
    Sum := Sum   K2;
  ShowMessage(FloatToStr(Sum));
end;

[DCC Error] Unit1.pas(36): E2032 For loop control variable must have ordinal type