C++ sax2 parser problem

Question

I want to parse an XML file. My XML looks like this:

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
  <name>tracker</name>
  <value>localhost:58303</value>
  <description>The host and port that the MapReduce job tracker runs
  at.  If "local", then jobs are run in-process as a single map
  and reduce task.
  </description>
</property>

</configuration>

I use the sxx 2 parser to parse this file. I want to chain the value of an element<value> from localhost to 192.168.0.5. I wrote some C++ code which looks like this:

#include <SAX2XMLReader.hpp>
#include <XMLReaderFactory.hpp>
#include <DefaultHandler.hpp>
#include <XMLString.hpp>"
#include <iostream>

using namespace std;
using namespace xercesc;

int main (int argc, char* args[]) {

    try {
        XMLPlatformUtils::Initialize();
    }
    catch (const XMLException& toCatch) {
        char* message = XMLString::transcode(toCatch.getMessage());
        cout << "Error during initialization! :\n";
        cout << "Exception message is: \n"
             << message << "\n";
        XMLString::release(&message);
        return 1;
    }

    char* xmlFile = "/home/project/conf/mapred.xml";
    SAX2XMLReader* parser = XMLReaderFactory::createXMLReader();
    parser->setFeature(XMLUni::fgSAX2CoreValidation, true);
    parser->setFeature(XMLUni::fgSAX2CoreNameSpaces, true);   // optional

    DefaultHandler* defaultHandler = new DefaultHandler();
    parser->setContentHandler(defaultHandler);
    parser->setErrorHandler(defaultHandler);

    try {
        parser->parse(xmlFile);
    }
    catch (const XMLException& toCatch) {
        char* message = XMLString::transcode(toCatch.getMessage());
        cout << "Exception message is: \n"
             << message << "\n";
        XMLString::release(&message);
        return -1;
    }
    catch (const SAXParseException& toCatch) {
        char* message = XMLString::transcode(toCatch.getMessage());
        cout << "Exception message is: \n"
             << message << "\n";
        XMLString::release(&message);
        return -1;
    }
    catch (...) {
        cout << "Unexpected Exception \n" ;
        return -1;
    }

    delete parser;
    delete defaultHandler;
    return 0;
}

The code compiles. What I want to know is how do I change the value in the XML file? How do I go about writing a handler for this and use it in my code? Can anybody explain what I need to do to successfully change a value in the XML file?