Frage zu einfache Mengentypen

[neolithos]

Was soll

Code:

SetLength(a, c);

Code:

procedure TForm1.Button1Click(Sender: TObject);
const
  csVocals : set of char = ['a', 'i', 'o', 'u', 'e'];
var sText : String;
    I,
    iCount : Integer;
begin
  sText := Edit1.Text;
  iCount := 0;
  for I := 1 to Length(sText) do
      if sText[I] in csVocals then
         Inc(iCount);
  Button1.Caption := IntToStr(iCount);
end;

ich hoffe es hilft