Question

I’m new to using XML with C++ and I want to loop through an XML node and print the ‘id’ attribute of into a vector. This is my XML

<?xml version="1.0" encoding="UTF-8"?>
<player playerID="0">
    <frames>
        <frame id="0"></frame>
        <frame id="1"></frame>
        <frame id="2"></frame>
        <frame id="3"></frame>
        <frame id="4"></frame>
        <frame id="5"></frame>
    </frames>
</player>

and this is how I’m loading the XML

rapidxml::xml_document<> xmlDoc;

/* "Read file into vector<char>"*/
std::vector<char> buffer((std::istreambuf_iterator<char>(xmlFile)), std::istreambuf_iterator<char>( ));
buffer.push_back('\0');
xmlDoc.parse<0>(&buffer[0]);

How do I loop through the node?

Answer 1

Once you’ve loaded xml into your document object, you can use first_node() to get specified child node (or just the first one); then you can use next_sibling() to go through all its siblings. Use first_attribute() to get node’s specified (or just first) attribute. This is an idea of how the code could look like:

#include <iostream>
#include <fstream>
#include <vector>
#include <sstream>
#include <rapidxml.hpp>
using std::cout;
using std::endl;
using std::ifstream;
using std::vector;
using std::stringstream;
using namespace rapidxml;

int main()
{
    ifstream in("test.xml");

    xml_document<> doc;
    std::vector<char> buffer((std::istreambuf_iterator<char>(in)), std::istreambuf_iterator<char>( ));
    buffer.push_back('\0');
    doc.parse<0>(&buffer[0]);

    vector<int> vecID;

    // get document's first node - 'player' node
    // get player's first child - 'frames' node
    // get frames' first child - first 'frame' node
    xml_node<>* nodeFrame = doc.first_node()->first_node()->first_node();

    while(nodeFrame)
    {
        stringstream ss;
        ss << nodeFrame->first_attribute("id")->value();
        int nID;
        ss >> nID;
        vecID.push_back(nID);
        nodeFrame = nodeFrame->next_sibling();
    }

    vector<int>::const_iterator it = vecID.begin();
    for(; it != vecID.end(); it++)
    {
        cout << *it << endl;
    }

    return 0;
}