title: Validating email address without regex
body: <p>This <em>must</em> have a canonical answer but I cannot find it... <a href="https://stackoverflow.com/questions/201323/using-a-regular-expression-to-validate-an-email-address">Using a regular expression to validate an email address</a> has answers which show regex is really <em>not</em> the best way to validate emails. Searching online keeps turning up lots and lots of regex-based answers.</p>
  
  <p>That question is about PHP and an answer references a handy class <code>MailAddress</code>. C# has something very similar but what about plain old C++? Is there a boost/C++11 utility to take all the pain away? Or something in WinAPI/MFC, even?</p>