title: boost regex sub-string match
body: <p>I want to return output "match" if the pattern "regular" is a sub-string of variable st.  Is this possible?</p>
  
  <pre><code>int main()
  {
    string st = "some regular expressions are Regxyzr";
  
    boost::regex ex("[Rr]egular");
    if (boost::regex_match(st, ex)) 
    {
      cout &lt;&lt; "match" &lt;&lt; endl;
    }
    else 
    {
      cout &lt;&lt; "not match" &lt;&lt; endl;
    }
  }
  </code></pre>