模拟8位2进制的加一计数，（但是a（7）老是调试溢出。。。望指点）

Dim a(7) As Integer
Dim i, j, k, num, flag

i = 0
num = 1'默认0为一个
flag = 0 '清空记位器
k = 7

For i = 0 To 7 '清0
a(i) = 0
Next i

Do While flag < 8 '当有8个1结束


   a(7) = a(7) + 1 '从末位加1
   
   For k = 7 To 1  '2进制进位
      If a(k) > 1 Then
         a(k) = 0
        a(k - 1) = 1
        num = num + 1 '计数
      End If
  Next k
  
  
  flag = 0 '清空记位器
  
  For j = 0 To 7 '记录有几个1
      If a(j) = 1 Then
      flag = flag + 1
      End If
  Next j
Loop

MsgBox "num"