参考答案

Option Base 1
Private Function FindMax(a() As Integer)
    Dim Start As Integer
    Dim Finish As Integer, i As Integer
    Start = LBound(a)
    Finish = UBound(a)
    Max = a(Start)
    For i = Start To Finish
        If a(i) > Max Then Max = a(i)
    Next i
    FindMax = Max
End Function
Private Sub Command1_Click()
    Dim arr1
    Dim arr2(4) As Integer
    arr1 = Array(Val(Text1.Text), Val(Text2.Text), Val(Text3.Text), Val(Text4.Text))
    For i = 1 To 4
        arr2(i) = CInt(arr1(i))
    Next i
    M = FindMax(arr2())
    Print "最大值是: "; M
End Sub