用VB做一个程序题目是这样的：输入行数显示该行数的杨辉三角

如题所述

Private Sub Form_Click() '能输出20行以下的
   Dim a()
   Dim n As Integer
   Me.AutoRedraw = True
   Cls
   n = Val(InputBox(" 请你输入行数！"))
   If n >= 1 And n <= 20 Then
      ReDim a(1 To n, 1 To n)
      For i = 1 To n
         For j = 1 To n
            If i = j Or j = 1 Then a(i, j) = 1
         Next j
      Next i
      For i = 1 To n
         For j = 1 To i
            If j <> 1 And i <> j Then
               a(i, j) = a(i - 1, j - 1) + a(i - 1, j)
            End If
        Next j
       Next i
      For i = 1 To n
         For j = 1 To i
            Print Tab(j * 2 * (3 + n / 8) - i * (3 + n / 8) + 15 * (1 + n / 3)); a(i, j);
         Next j
         Print
       Next i
    End If
End Sub

这 段代码 什么意思啊
嗯解释下么 谢谢啊