单项选择题

假定有以下两个过程：
Sub s1(ByVal x As Integer,ByVal y As Integer)
Dim t As Integer
1=x
x=y
y=t
End Sub
Sub S2(x As Integer,y As Integer)
Dim t As Integer
t=x:x=y:y=t
End Sub
下列说法正确的是______。