ActiveSupport::CoreExtensions::Integer::EvenOdd

For checking if a fixnum is even or odd.

  2.even?  # => true
  2.odd?   # => false
  1.even?  # => false
  1.odd?   # => true
  0.even?  # => true
  0.odd?   # => false
  -1.even? # => false
  -1.odd?  # => true