How to manually create a boost ptree with different XML attributes? - c++

Question

I am using boost libraries to parse XML files and I have to create a ptree manually.
I want to create below xml file using boost ptree.
<?xml version="1.0"?>
<Txn>
<Resp errCode="0" errInfo="" />
<A exptime="20171230">xyz Information</A>
<B>xyz Information</B>
<C type="Active">xyz Information</C>
</Txn>
To achieve above xml,
Below is my sample code:
boost::property_tree::ptree pt;
boost::property_tree::ptree ptr1;
boost::property_tree::ptree ptr2;
boost::property_tree::ptree ptr3;
ptr1.put("<xmlattr>.errCode", Txn.resp.errCode);
ptr1.put("<xmlattr>.errInfo", Txn.resp.errInfo);
ptr2.push_back(boost::property_tree::ptree::value_type("A", boost::property_tree::ptree(data)));
ptr2.push_back(boost::property_tree::ptree::value_type("C", boost::property_tree::ptree(data)));
ptr2.put("A.<xmlattr>.exptime", data);
ptr2.put("C.<xmlattr>.type", data);
ptr3.put("<xmlattr>", data);
pt.add_child("Txn.Resp", ptr1);
pt.add_child("Txn", ptr2);
pt.add_child("Txn.B", ptr3);
Here Child A and C always create as a separate with Parent Txn But I want to add all child in Txn Parent
. I did not understand, why child A and C are different here.
It would be very helpful, If someone help me to provide right way.

Answer 1

Here's the simplest thing I can think of:
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#include <boost/property_tree/xml_parser.hpp>
#include <iostream>
using boost::property_tree::ptree;
static auto pretty = boost::property_tree::xml_writer_make_settings<std::string>(' ', 4);
int main() {
ptree root;
root.add("Txn.Resp.<xmlattr>.errCode", 0);
root.add("Txn.Resp.<xmlattr>.errInfo", "");
root.add("Txn.A", "xyz Information");
root.add("Txn.A.<xmlattr>.exptime", "20171230");
root.add("Txn.B", "xyz Information");
root.add("Txn.C", "xyz Information");
root.add("Txn.C.<xmlattr>.type", "Active");
write_xml(std::cout, root, pretty);
}
Prints:
<?xml version="1.0"?>
<Txn>
<Resp errCode="0" errInfo="" />
<A exptime="20171230">xyz Information</A>
<B>xyz Information</B>
<C type="Active">xyz Information</C>
</Txn>
Key point is to create the element node before adding attributes, otherwise you get this instead:
Live On Coliru
<?xml version="1.0" encoding="utf-8"?>
<Txn>
<Resp errCode="0" errInfo=""/>
<A exptime="20171230"/>
<A>xyz Information</A>
<B>xyz Information</B>
<C type="Active"/>
<C>xyz Information</C>
</Txn>