function ReverseStr(S: string): string;
begin
  Result := SysUtils.EmptyStr;
  while System.Length(S) > 0 do
  begin
    Result := Result + StrUtils.RightStr(S, 1);
    S := StrUtils.LeftStr(S, Pred(System.Length(S)));
  end;
end;
//delphi/2324