palindrome program

palindrome.rb

def palindrome?(string)
  head = 0
  tail = string.length - 1

  while string[head] == string[tail]
    head += 1
    tail -= 1
    if tail < head
      puts 'palindrome'
    else
      puts 'not palindrome'
    end
  end
end

palindrome?("racecar")
palindrome?("hello")
palindrome?("race car")