peterburg.rb

'''
  Implementation of a simulation of a St. Petersburg paradox
  For more info, visit:
  https://en.wikipedia.org/wiki/St._Petersburg_paradox

'''

class Toss
  attr_reader :n
  
  HEADS = 0
  TAILS = 1
  STAKE = 2

  def initialize(n = 1)
    @n = n
  end

  def winnings
    action = [HEADS, TAILS].sample
    
    if action == HEADS
      Toss.new(n + 1).winnings
    else
      pot
    end
  end

  def pot
    2**n
  end
end

n_steps = 100_000_000

wins = []
(1..n_steps).each do |time|
  toss = Toss.new
  wins << toss.winnings
end

puts(wins.sum / wins.length)