title: set a boolean value
body: <p>Hi I'm working with boolean values and I'm a little bit confused. I have a boolean value:</p>
  
  <pre><code>boolean answer;
  </code></pre>
  
  <p>This can have two values : yes or not.</p>
  
  <p>If I insert from standard input the string "yes" it became true otherwise false. How can i do?</p>