请VB高手帮忙，解释一下这段程序！

看不懂了,请高手指点,谢谢!
For k = 1 To 16
For j = 1 To 29
If k > 13 Then
strj = "A" + Chr(38 + 2 * k) + Trim(Str(j + 4))
Else
strj = Chr(64 + 2 * k) + Trim(Str(j + 4))
End If
Range(strj).Select
c(j, k) = c(j, k) + Val(Selection.Value)
Next j
Next k