[s0Creator]

Код:

function sti(s: string): int64;
var
  i, x : integer;
begin
  Result := 0;
  s := Trim(s);
  x := Ord('0');
  for i := 1 to Length(s) do
  begin
    if not (s[i] in ['0'..'9'])then
    begin
      Result := 0;
      exit;
    end;
    Result := (Result * 10) + (Ord(s[i]) - x);
  end;
end;