Armstrong numbers

armstrong_nums.rb

def is_armstrong(num)
  num = num.to_s
  sum = 0
  num.each_char do |i|
    i = i.to_i
    sum += (i ** 3)
  end
  num = num.to_i
  if sum == num
    puts "#{num} is armstrong number"
  else
    puts "#{num} is not armstrong number"
  end
end

def find_armstrong_nums(range)
  (1..range).each do |num|
    num = num.to_s
    sum = 0
    num.each_char do |i|
      i = i.to_i
      sum += (i ** 3)
      num = num.to_i
    end
    if sum == num
      puts num
    end
  end
end

is_armstrong(153)
find_armstrong_nums(1000)