VB编程将6～100之间的全部偶数表示为两个素数之和，在列表框显示结果，由label 1显示共有多少对素数之和。

Question

界面：一个按钮触发列表框显示数据，和一个label显示“6～100之间有X对素数和”
比如10=5+5,10=3+7

Answer 1

此题需要先编写一个求素数的自定义函数，具体如下：
1.打开VB，画一个ListBox控件，名称List1,再画一个Label控件，名称Label1
2.画一个Command控件，名称Command1
3.双击Command1，打开代码窗口，输入如下代码：

Function PDsu(a As Integer) As Integer
Dim b As Integer: Dim i As Integer
If a <= 3 Then
PDsu = 1
Else
b = a \ 2
For i = 2 To b
If (a Mod i) = 0 Then
PDsu = 0: Exit Function
Exit For
End If
Next i
PDsu = 1
End If
End Function

Private Sub Command1_Click()
Dim m As Integer
Dim n As Integer
Dim i As Integer
Dim s As Integer
s = 0
For i = 6 To 100 Step 2
For m = 2 To i - 2
n = i - m
If (PDsu(m) = 1) And (PDsu(n) = 1) Then
List1.AddItem Str(i) & "=" & Str(m) & "+" & Str(n): s = s + 1
Exit For
End If
Next m
Next i
Label1.Caption = "6-100间共有" & Str(s) & "对素数和"
End Sub

4.如果操作输入无误，即可以显示正常结果，共有48对素数和
说明：解答此题，我用了约10分钟，给我加分吧

Answer 2

Private Sub Command1_Click()
Dim a As Integer, b As Integer
Dim i As Integer, j As Integer
Dim k As Integer

a = 6
b = 100

List1.Clear
For i = a To b Step 2
For j = 2 To i / 2
If Prime(j) And Prime(i - j) Then
k = k + 1
List1.AddItem CStr(k) & "： " & CStr(i) & "=" & CStr(j) & "+" & CStr(i - j) '修改这里的代码就行了
End If
Next j
Next i
Label1.Caption = "6～100之间有" & CStr(k) & "对素数和"
End Sub

'判断是否为素数
Private Function Prime(n As Integer) As Boolean
Dim i As Integer
If n = 1 Then
Exit Function
ElseIf n = 2 Then
Prime = True
Exit Function
ElseIf n Mod 2 = 0 Then
Exit Function
End If
For i = 3 To Sqr(n) Step 2
If n Mod i = 0 Then Exit Function
Next i
Prime = True
End Function