学步园

type
  TdyArr = array of Integer;

function myFunc(var dyArr: TdyArr): integer;
var
  i, d: Integer;
begin
  Result := 2 * dyarr[0];
  for i := Low(dyarr) to High(dyArr) do
    Result := Result - dyArr[i];
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  DyArr: TdyArr;
begin
  SetLength(DyArr, 3);
  DyArr[0] := -1;
  DyArr[1] := 4;
  DyArr[2] := 18;
  Memo1.Lines.Add(IntToStr(myFunc(DyArr)))
end;