1. 下列VB程序用于求2个正整数（均小于10000）的最大公约数，请在程序划线处填入合适的代码。

Private Sub Command1_Click()

Dim x As Integer, y As Integer, z As Integer

x=Val(Text1.Text): y=Val(Text2.Text)

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Text3.Text=Str(z)

End Sub

Function gcd(a As Integer, b As Integer)As Integer

Do While a< >b

 If a>b Then a=a-b Else b=b-a

Loop

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End Function

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