请问一下两段代码的区别是什么,为什么一个结果是0,一个是10?
第一段:
Private Sub Form_Click()
Dim a As Integer
For i = 1 To 10
Call abcd(a)
Next i
Print a
End Sub
Sub abcd(ByVal x)
x = x + 1
End Sub
第二段:
Private Sub Form_Click()
Dim a As Integer
For i = 1 To 10
Call abcd(a)
Next i
Print a
End Sub
Sub abcd(x)
x = x + 1
End Sub
请通俗地讲一下原理,谢谢