刚开始学VB,帮我看看这一句什么问题，谢谢

Private Sub command1_click()
  Dim a, b, c As Single
  Me.Cls
  Me.AutoRedraw = True
  a = Val(InputBox("请输入数字", "输入对话框", "1"))
  b = 1
  For i = a To 1 Step -1
    Print Tab(i); String(b, "*")
    b = b + 2
  Next i
  b = a * 2 - 3
  For j = 1 To a - 1  '最多的循环已经在上一循环里画了，本次循环要比上次循环少一个
    Print Tab(j + 1); String(b, "*")
    b = b - 2
  Next j
End Sub

'另一种方法
Private Sub command1_click()
  Dim a As Integer, b As Integer, c As Integer
  Me.Cls
  Me.AutoRedraw = True
  a = Val(InputBox("请输入数字", "输入对话框", "1"))
  b = 1
  c = 1
  While b > 0
    Print Tab(a - b + 1); String(b * 2 - 1, "*")
    b = b + c
    If b = a Then c = -1
  Wend
End Sub