填空题
下列程序段的功能是，单击命令按钮后，将随机产生10个三位数，并将这些数写到C盘根目录下的data.txt文件中。请填空。
Private Sub Command1_Click()
Dim a As Integer
Open{{U}} {{U}} {{/U}} {{/U}}For Output As #100
Randomize
For i =1 To 10
a=100+Int(899*Rnd)
{{U}} {{U}} {{/U}} {{/U}}
Next i
Close #100
End Sub