Largest five adjacent number

Largest five adjacent number is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

Generate random 1000-digit number.
Find the four adjacent digits in the 1000-digit number that have the greatest product are.

Ring

<lang ring> digit = "" max = 0 maxOld = 0 limit = 1000

for n = 1 to limit

   rand = random(9)
   randStr = string(rand)
   digit += randStr

next

for n = 1 to len(digit)-5

   res = substr(digit,n,5)
   resNum = number(res)
   if resNum > maxold 
      max = resNum
      maxOld = max
   ok

next

see max + nl </lang>

Output:

99638