def fib1(i)

  curr = 0
  success = 1
  n = 0

  while (n < i)
    curr,success = success, curr + success
    n += 1
  end

  curr
end

def fib2(i)

  curr = 0
  success = 1
  n = 0

  while (n < i)
    tmp = success
    success = curr + success
    curr = tmp
    n += 1
  end

  curr
end

# Written in a more Ruby-like way.
def fib3(i)
  curr = 0
  success = 1

  (i - 1).times do
    curr, success = success, curr + success
  end

  curr
end

p 5.times.map {|i| fib1 i }
p 5.times.map {|i| fib2 i }
p 5.times.map {|i| fib3 i }