填空题 执行下面的程序，单击Command1按钮，则窗体上显示的a(3，1)的值为 1，a(1，2)的值为 2。
Option Explicit
Option Base 1
Private Sub Command1_Click()
Dim A(3, 3) As Integer, i As Integer, j As Integer
For i=1 To 3
For j=1 To 3
A(i, j)=j*10+i
Next j
Next i
Call ExChange(A)
End Sub
Private Sub ExChange(X() As Integer)
Dim i As Integer, j As Integer, t As Integer
For i=1 To 2
For j=1 To 4-i
t=X(i, j)
X(i, j)=X(4-i, 4-j)
X(4-i, 4-j)=t
Next j
Next i
For i=1 To 3
For j=1 To 3
Print X(i, j);
Next j
Print
Next 1
Print
End Sub