title: EXC_BAD_ACCESS when trying to build string by using %@ for an int
body: <p>For the use within Core Data I tried to build a <code>NSPredicate</code> object. <code>minLength</code> and <code>maxLength</code> are of type<code>int</code>:</p>
  
  <pre><code> NSPredicate *predicate = [NSPredicate predicateWithFormat:@"length &gt;= %@ AND length &lt;= %@",
                            minLength, maxLength];
  </code></pre>
  
  <p>The program crashes here with an <code>EXC_BAD_ACCESS</code>. This is not the case if I use <code>%d</code> instead of <code>%@</code>:</p>
  
  <pre><code> NSPredicate *predicate = [NSPredicate predicateWithFormat:@"length &gt;= %d AND length &lt;= %d",
                            minLength, maxLength];
  </code></pre>
  
  <p>What am I missing here?</p>