rebol [
  title: "compute average"
  author: "vpavlu"
  date: 9-Dec-2002/12:54
  home: http://plain.at/vpavlu
]

sum: 0
count: 0

while [ "" <> num: ask "(leave blank to quit) enter a number: " ][
  sum: sum + to-integer num
  count: count + 1
  print [ "average is" (sum / count)]
]