array iteration problem http://blog.jazzychad.net/2012/08/01/array-iteration-problem.html

add1.rb

def add1(arr, val, n)
  limit = (n == 0 ? arr.length : n.abs)

  enumerator = (n < 0 ? (arr.length-1).downto(0) : (0).upto(arr.length-1))
  enumerator.each do |i|
    if arr[i] == val
      arr[i] += 1
      limit -= 1
    end

    break if limit == 0
  end
  arr
end