有一组正整数，要求供对其中的素数进行升序排序。排序后素数在前，非素数在后。排序示例如下。

排序前	86	71	5	41	81	79	37	89
排序后	5	37	41	71	79	89	86	81

 
Const n = 8
Dim a(1 To n) As Integer
Private Sub Command1_Click()

Dim i As Integer, j As Integer, k As Integer, t As Integer

Dim flag As Boolean

'读取一组正整数，存储在数组a中，代码略

For i = 1 To n – 1

 _____________

   If IsPrime(a(k)) Then flag = True Else flag = False

For j = i + 1 To n
If IsPime(a(j)) Then
If   Then ______________
k = j
flag = True
End If

End If

Next j

If k <> i Then

t = a(k): a(k) = a(i): a(i) = t

End If

If Not flag Then Exit For  'Exit For表示退出循环

Next i

'依次输出排序后的数据。代码略

End Sub
Function IsPrime(m As Integer) As Boolean
'本函数判断m是否是素数：是素数返回值为True，不是素数返回值为False
'代码略
End Function