帮忙做个VB程序，急~~~

准备一个文件“c:\1.txt”，第一行为几年，下面为每年的数据
自然增长率=出生率-死亡率
Private Sub Command1_Click()
Dim a(), i As Integer, N As Integer
Open "c:\1.txt" For Input As #1
Input #1, N

ReDim a(1 To N, 0 To 5)
For i = 1 To N
Input #1, a(i, 0), a(i, 1), a(i, 2), a(i, 3), a(i, 4)
a(i, 5) = a(i, 2) - a(i, 4)
Print a(i, 0); "年的自然增长率为千分之"; a(i, 5)
Next i
Close
End Sub