怎么编写VB 取最大值

求最大值就是，取第一个数给临时变量，然后用临时变量去跟数组的数比较，如果数组的值大于临时变量的值，则用数组的值替换临时变量的值，数组检索完成最后得到的就是数组里面最大的值。取最小值也是一样的道理。

例子，取最大最小值：
Private Function Max(Data() As Double) As Double '求实数最大值函数
Dim i As Long
Dim x1 As Long, x2 As Long

x1 = LBound(Data)
x2 = UBound(Data)
Max = Data(x1)
For i = x1 To x2
If Data(i) >= Max Then Max = Data(i) '如果数组当前值比Max值大，替换Max中的值
Next

End Function
Private Function Min(Data() As Double) As Double '求实数最小值函数
Dim i As Long
Dim x1 As Long, x2 As Long

x1 = LBound(Data)
x2 = UBound(Data)
Min = Data(x1)
For i = x1 To x2
If Data(i) <= Min Then Min = Data(i) '如果数组当前值比Min值大，替换Min中的值
Next

End Function

Private Sub Command1_Click() '点击按钮求随机数组最大值
Dim a As Integer, b As Integer
Dim Maxs As Double, Mins As Double
Dim temps(100) As Double

Randomize '定义生成的随机数为不重复模式
For i = 0 To 100
If Rnd() > 0.5 Then temps(i) = 100 * Rnd() Else temps(i) = -100 * Rnd() '生成101个100以内的随即实数
Next

Maxs = Max(temps) '调用Max函数求实数最大值
Mins = Min(temps) '调用Min函数求实数最小值
Me.Cls
Me.Print Maxs '显示实数到窗体
Me.Print Mins

End Sub

Sub aa()
Dim i&
i = Max(Range("A1:D18"))
mxgbox i
End Sub

dim a,b
dim max
max=Max(a,b)

一楼不对，首先要定义max（）作用的
If a>b
then max=a
else
max=b