title: User Input , How can we do it?
body: <p>How can we get something from user in prolog : 
  for example :</p>
  
  <pre><code>animal(dog).
  animal(cat).
  write('please type animal name:'),nl.
  /* How to read from user and store it to X 
  and then check that user has typed animal name ?*/
  ?-animal(X).
  </code></pre>