想问一下这串代码在vb里是什么意思呢？

Private Sub PopSort() ′气泡排序法
Dim i, j, Temp As Integer
For i = 7 To 2 Step －1
For j = 7 － 1 To 1 Step －1
If i >= 7 － j ＋ 1 Then
If NumArray(j ＋ 1) < NumArray(j) Then
Temp = NumArray(j)
NumArray(j) = NumArray(j ＋ 1)
NumArray(j ＋ 1) = Temp
End If
End If
Next j
Next i
End Sub

从小到大排序.