title: ||, && operators in C
body: <p>Why this code only work with <code>&amp;&amp;</code> operator?  </p>
  
  <p>I think it should be <code>||</code>, but I'm wrong. <code>Choice</code> can not be equal to 2 value at the same time?  </p>
  
  <p>I need to ask user's input until choice will be equal  to <code>'a'</code> OR <code>'d'</code>, but why I need to write <code>&amp;&amp;</code> ?  I don't get it.</p>
  
  <pre><code>do
  {
      scanf("%c", &amp;choice);
  } while ( choice != 'a' &amp;&amp; choice != 'd' );
  </code></pre>
  
  <p>I wanted to use <code>||</code>, but it's not working.</p>