用VB编程 求4~50之间的偶数表示成两个素数的和.用Funtion实现

Private Sub Command1_Click()
Dim i As Integer
For i = 4 To 50 Step 2
Call caixiang(i)
Next
End Sub
Function caixiang(ByVal n As Integer)
Dim i As Integer
For i = 2 To n \ 2
If isPrime(i) = True And isPrime(n - i) = True Then
Print n & "=" & i & "+" & n - i
End If
Next
End Function
Function isPrime(ByVal n As Integer) As Boolean
Dim i As Integer
isPrime = False
For i = 2 To n - 1
If n Mod i = 0 Then Exit For
Next
If i > n - 1 Then isPrime = True
End Function