//给一个整型开放数组求和的函数
function MyFun(const arr: array of Integer): Integer;
var
  i: Integer;
begin
  Result := 0;
  for i in arr do Result := Result + i;
end;

{测试1:}
procedure TForm1.Button1Click(Sender: TObject);
var
  num: Integer;
begin
  num := MyFun([1,2,3]);
  ShowMessage(IntToStr(num)); {6}
end;

{测试2:}
procedure TForm1.Button2Click(Sender: TObject);
var
  iArr: array of Integer;
  i,x: Integer;
begin
  SetLength(iArr, 10);

  for i := Low(iArr) to High(iArr) do
  begin
    iArr[i] := i + 1;
  end;

  x := MyFun(iArr);
  ShowMessage(IntToStr(x)); {55}
end;