在窗体中添加一个命令按钮(名为Command1)和一个文本框(名为text1)，然后编写如下事件过程：
Private Sub Command1_Click()
Dim X As Integer, y As Integer, z As Integer
x=5: y=7: z=0
Me!Text1=""
Call p1(x, y, z)
Me!Text1=z
End Sub
Sub p1(a As Integer, b As Integer, C As Integer)
c=a+b
End Sub
打开窗体运行后，单击命令按钮，文本框中显示的内容是______。