设有如下通用过程:Public Function Fun(xStr As String) As StringDim tStr As String,strL As IntegertStr= strL=Len(xStr)i=1Do While i<=strL 2tStr=tStr & Mid(xStr,i,1) & Mid(xStr,strL-i+1,1)i=i+1LoopFun=tStrEnd Function在窗体上画一个名称为Command1的命令按钮。然后编写如下的事件过程:Private Sub Command1_Click()Dim S1 As StringS1= abcdef Print UCase(Fun(S1))End Sub程序运行后,单击命令按钮,输出结果是
A.ABCDEF
B.abcdef
C.AFBECD
D.DEFABC