执行下面程序,当单击 Cmd1时,在窗体上显示的第一行内容是 ,第二行的内容是 ,第四行的内容是 。 Option Explicit Private Sub Cmd1_Click() Dim a As Integer, b As Integer a = 1 b = 2 Print fun(2 * b, fun( ( a ) , b)) Print a; b End Sub Private Function fun(x As Integer, y As Integer) As Integer x = x + 2 y = x - y + 3 fun = x + y Print fun End Function