Find the sum of all the even-valued terms in the Fibonacci sequence which do not exceed four million.

euler-002.rb

#!/usr/bin/env ruby
#
# Problem: Find the sum of all the even-valued terms in the Fibonacci sequence which do not exceed four million.
# Description: Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:
#
# 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...
#
# Find the sum of all the even-valued terms in the sequence which do not exceed four million.
#
# Solution:
#

current = 0
succeeding = 1
sum = 0
limit = 4000000

while (current < limit) do
  current, succeeding = succeeding, current + succeeding
  sum += current if (current%2).zero?
  if current < limit
    next
  else
    puts sum and break
  end
end