title: Extract IP address from a string using boost regex?
body: <p>I was wondering if anyone can help me, I've been looking around for regex examples but I still can't get my head over it.</p>
  
  <p>The strings look like this:</p>
  
  <p><em>"User JaneDoe, IP: 12.34.56.78"</em></p>
  
  <p><em>"User JohnDoe, IP: 34.56.78.90"</em></p>
  
  <p>How would I go about to make an expression that matches the above strings?</p>