title: C++ std::regex How to fix the error_complexity?
body: <p>I used <code>std::regex</code> to match a string. </p>
  
  <p>My define of regex is : </p>
  
  <pre><code>regex reg("(-?\\d+,?){2,}", regex::icase)
  </code></pre>
  
  <p>Test string is : </p>
  
  <pre><code>5,3240,7290,11340,-3240,-7290,-11340
  </code></pre>
  
  <p>I used std function of <code>regex_match()</code>.
  The following is the error I got.</p>
  
  <blockquote>
    <p>regex_error(error_complexity): The complexity of an attempted match
    against a regular expression exceeded a pre-set level.</p>
  </blockquote>
  
  <p>How can I fix the problem ? My compiler is VS2013.</p>