VB取最接近的数问题

a(0) = 2000
a(1) = 4000
a(2) = 6000
.....
.....

b 是随机数的

如果这时 b= 5000

我要把最接近的数 6000(a2) - b

应该怎样做呢?

貌似 4000,6000一样近把。

dim result as long
dim j as long 
dim b as long 

b=5000
result =999999

for i=0 to ubound(a)
  if (asb(a(i)-b)<asb(result) then
  result =asb(a(i)-b)
  j=i
  end if 
next i

debug.print "最接近的数为a(" & j & "),差值为：" & result