title: regex for allowing alphanumeric, special characters and not ending with @ or _ or
body: <p>I am new to regex , I created below regex which allows alpha numeric and 3 special characters @._ but string should not end with @ or . or *</p>
  <pre><code>^[a-zA-Z0-9._@]*[^_][^.][^@]$
  </code></pre>
  <p>it validates abc@ but fails for abc.</p>