title: What does `return 1 + strlen_rec(&arr[1]) ;` mean?
body: <p>I have some code:</p>
  
  <pre><code>int strlen_rec(char arr[])
  {
  
      if(arr[0]=='\0')
          return 0;
      else
          return 1 + strlen_rec(&amp;arr[1]) ;
  }
  </code></pre>
  
  <p>The line </p>
  
  <pre><code>return 1 + strlen_rec(&amp;arr[1]) ;
  </code></pre>
  
  <p>is confusing me. Can someone explain what it does?</p>