VB 麻烦把A矩阵改成下三角型显示,B上三角型显示

VB 麻烦把A矩阵改成下三角型显示,B上三角型显示
Private Sub Command1_Click()
Dim a(4, 4) As Integer
Dim i As Integer, j As Integer
For i = 1 To 4
For j = 1 To 4
a(i, j) = Int(Rnd * 41 + 30)
Print a(i, j);
Next j
Print
Next i
Print
Dim b(4, 4) As Integer
For i = 1 To 4
For j = 1 To 4
b(i, j) = Int(Rnd * 34 + 101)
Print b(i, j);
Next j
Print
Next i