TinyXML2 Parse data within the same element in C++

Question

I have an XML file like this:

<Aircraft callsign="MS842" type="B703">
  <State>89220.4892904 52914.9322014 8229.6 0 0 4.36332312999 0 0 70.0 270.741736633 0</State>
  <AutoPilot>
    <Mode setpoint="174.89485525" type="MODE_SPD_CAS"/>
    <Mode setpoint="8229.6" type="MODE_ALT_HLD"/>
    <Mode setpoint="4.36332312999" type="MODE_HDG_SEL"/>
  </AutoPilot>
</Aircraft>

I need to parse the data within the child element "State". What I need is data from specific locations within that element:

1. 1st data: px = 89220.4892904
2. 2nd data: py = 52914.9322014
3. 6th data: ph = 4.36332312999

where px, py and ph are some variables of type double.

If I run the following:

TiXmlElement* subelement = 0;
subelement = xmlac->FirstChildElement("State");
std::cout << "Elem : " subelement[0] << endl;

I get the following:

Elem : <State>89220.4892904 52914.9322014 8229.6 0 0 4.36332312999 0 0 70.0 270.741736633 0</State>

Is there a way like:

double px=0.0, py=0.0, ph=0.0;
px = subelement[0][0]
py = subelement[0][1]
ph = subelement[0][2]

which does the job? (I tried the above code. I get something called as a fragmentation error.)

NOTE:

• My experience in C++ is minimal. If the concepts are too cumbersome, please indicate sources for your answers/assumptions
• Language: C++
• xml parser: tinyxml

Thanks.

EDIT: Found the solution. See below

Answer 1

I used the following technique to get the string:

inline string getStringData(TiXmlElement* node)
{
  if (!node) return "";
  string ret;
  if (TiXmlNode* el = node->FirstChild()) {
    // Catch multirow data
    while (el) {
      if (el->Type() == TiXmlNode::TINYXML_TEXT)
        ret += el->ToText()->ValueStr();
      else
        return "";
      if ((el = el->NextSiblingElement())) ret += ' ';
    }
  }
  return ret;
}

And the following way to separate it out:

TiXmlElement* subelement = 0;
subelement = xmlac->FirstChildElement("State");

// Get the initial position and heading
string mystr = getStringData(subelement);
std::istringstream ss(mystr);
double val;
int idx = 0;
std::vector<double> res;
while(ss >> val) {res.push_back(val);}
for (idx = 0; idx < 10; idx++){
    if ((idx == 0) || (idx == 1) || (idx == 5)) {
        std::cout << idx << " " << res[idx] << endl;
    }
}

Answer 2

I suggest to use GetText http://www.grinninglizard.com/tinyxmldocs/classTiXmlElement.html#b1436857d30ee2cdd0938c8437ff98d5 function to extract the string of data from the node and then use stringstream to parse it

I'm sure you can find a lot of samples how to do it. Here is the simple one

#include<vector>
#include<sstream> 

std::vector<double> parse(const std::string& data)
{
    std::istringstream ss(data);
    double val;
    std::vector<double> res;
    while(ss >> val){
        res.push_back(val);
    }
    return res;
}