![[单项选择题] 单击窗体时，下列程序的执行结果是 Private Sub Invert(By Val xstr As String，ystr As String) Dim tempstr AS](http://www.mshxw.com/aiimages/31/260209.png "[单项选择题] 单击窗体时，下列程序的执行结果是 Private Sub Invert(By Val xstr As String，ystr As String) Dim tempstr AS")
[单项选择题] 单击窗体时，下列程序的执行结果是 Private Sub Invert(By Val xstr As String，ystr As String) Dim tempstr AS String Dim I AS Integer I=Len(xstr) Do While I＞=1 tempstr=tempstr + Mid(xstr，I，1) I=I - 1 Loop ystr=tempStr End Sub Private Sub Form_Click( ) Dim s1 As String，s2 As String S1="abcdef" Invert S1，S2 Print S2 End Sub
A．abcdef
B．afbecd
C．fedcba
D．defabc
参考答案：
C问题解析:
解析：Invert(By Val xstr As String，ystr As String)的作用是将参数xstr的字符逆序处理，然后赋值给ystr，而ystr是按地址引用的，可以直接返回处理结果。
