有如下VB程序段:
Dim i As Integer, sum As Integer, a(0 To 7) As Integer
Dim s As String , ch As String , num As String
s="2-3-4-5-6-7-0"
sum=1:num=""
For i=1 To Len(s)
ch=Mid(s,i,1)
If ch>="0" And ch<="9" Then
num=num+ch
Else
sum=sum*Val(num)
a(Val(num))=Val(num)
End If
Next i
Text1.Text=Str(sum)
执行该程序段后,下列说法正确的是( )