Private X As Integer

Private Sub Command1_Click()
X = 5: Y = 3
Call proc(X, Y)
Label1.Caption = X
Label2.Caption = Y
End Sub
Private Sub proc(ByVal a As Integer, ByVal b As Integer)
X = a * a
Y = b + b

End Sub

如果有前面加多这句Private Y As Integer就是6！真的好容易犯错啦！怎样才能区分呢？因为没学过，自学看书很容易就忽略了。。。就像另一道题是不是也要看传址与传值吗？怎样才能很好的掌握这类题型呢？运行结果总是出乎我的计算的?
Private Sub Form_Click()
Dim a As Integer, b As Integer
a = 20: b = 50
p1 a, b
p2 a, b
p3 a, b
Print "a="; a, "b="; b
End Sub
Sub p1(x As Integer, ByVal y As Integer)
x = x + 10
y = y + 20
End Sub
Sub p2(x As Integer, ByVal y As Integer)
x = x + 10
y = y + 20
End Sub
Sub p3(x As Integer, ByVal y As Integer)
x = x + 10
y = y + 20
End Sub

明白了!一语点破啦!没学过真的好难把握啦!