使用inputbox接受来自键盘输入的圆的半径，把这个圆的直径、面积和周长的值显示在窗体的一个标签上。

Public Sub yuan(aa As Double)

Dim zhijing As Double
Dim zhouchang As Double
Dim mianji As Double
Const pi = 3.14
aa = Val(InputBox("请输入圆的半径", "输入数据"))
zhijing = 2 * aa
zhouchang = pi * aa
mianji = 2 * pi * aa * aa
Label1.Caption = "直径是：" & zhijing & vbCrLf & "周长是：" & zhouchang & vbCrLf & "面积是：" & mianji
End Sub
Private Sub Command1_Click()
Label1.Caption = ""
yuan (aa)
End Sub

Private Sub Command2_Click()
End
End Sub

Private Sub Form_Load()
yuan (aa)
End Sub