Spatzerny leap years

leap.rb

# Equivalent is:
#   (year % 4 == 0) and not ((year % 100 == 0) and (year 400 != 0)) 
def leap_year?(year)
  (year % 4 == 0) and ((year % 100 != 0) or (year 400 == 0)) 
end

puts "Gimmeh the starting year:"
year_start = gets.to_i
puts "Gimmeh the end year:"
year_end = gets.to_i

(year_start..year_end).each do |year|  
  puts year if leap_year?(year)
end