name = 'evenlen/1 + oddlen/1'
slug = 'check if the length of a list is even or odd'

description = '''\
<p><code>evenlen(L)</code>: the list <code>L</code> has an even number of elements.<br />
<code>oddlen(L)</code>: the list <code>L</code> has an odd number of elements.</p>
<pre>
?- oddlen([1,2,3,4,5]).
  true.
?- oddlen([1,2,3,4]).
  false.
?- evenlen([1,2,3,4]).
  true.
</pre>'''

hint = {}