求VB编程计算器

'建立两个label:label1、Value
'建立34个command:cmdCE、equl、calu(0——3)、CmdPoint、sign、CmdOn、num(0——9)、Vir(0——6)、quit、spci(0——6)
Option Explicit
Dim cal As Boolean
Private n(100) As Double
Private c(100) As Byte, m As Byte
Const pi As Double = 3.14159265358979
Private Sub cmdce_Click()
Value.Caption = "0"
cal = True
End Sub

Private Sub calu_Click(Index As Integer)
On Error GoTo err
Dim i As Byte
Dim res As Double
i = Len(Value.Caption)
If InStr(Value.Caption, ".") Then
Do While Mid(Value.Caption, i, 1) = "0"
i = i - 1
Loop
If Mid(Value.Caption, i, 1) = "." Then i = i - 1
Value.Caption = Left(Value.Caption, i)
End If
res = Val(Value.Caption)
If m = 1 Then
n(1) = res
c(1) = Index
m = 2
ElseIf Index < 2