title: How to extract child data with pugixml?
body: <p>I am experimenting with pugixml to extract data from a large XML file. I only am interested in  the values of the values in the nodes BAR and Nm:</p>
  
  <pre><code>    &lt;Document xmlns="xxxxxx" xmlns:xsi="vvvvvvv"&gt;
        &lt;Outer&gt;
          &lt;HDR&gt;
            &lt;MsgId&gt;FOOBAR222222&lt;/MsgId&gt;
            &lt;ID&gt;
              &lt;AAAAA&gt;FOOBAR222222&lt;/AAAAA&gt;
            &lt;/ID&gt;
          &lt;/HDR&gt;
          &lt;ENTRY&gt;
            &lt;Status&gt;existing&lt;/Status&gt;
            &lt;ELEM&gt;
              &lt;TM&gt;2012-11-19T13:00:00&lt;/TM&gt;
            &lt;/ELEM&gt;
            &lt;FOO&gt;
              &lt;BAR&gt;xxxxx&lt;/BAR&gt;
              &lt;NM&gt;
                &lt;Nm&gt;yyyyyyy&lt;/Nm&gt;
              &lt;/NM&gt;
            &lt;/FOO&gt;
          &lt;/ENTRY&gt;
  </code></pre>
  
  <p>From what I saw, it's possible to walk the root document, however, I am getting a bit lost on accessing parent and child nodes:</p>
  
  <pre><code>        void walk(xml_node parent)
          {
              for(xml_node child = parent.first_child(); child; child = child.next_sibling())
              {
                // ... Would like to output:  "FOO: xxxx  / NM:  yyyyyyyy"
              }
          }
  </code></pre>