Build an xml tree from scratch - pugixml C++ - c++

Question

Firstly I would like to say that I have been using an XML parser written by Frank Vanden Berghen and recently trying to migrate to Pugixml. I am finding the transition bit difficult. Hoping to get some help here.
Question: How can I build a tree from scratch for the small xml below using pugixml APIs? I tried looking into the examples on the pugixml home page, but most of them are hard coded with root node values. what I mean is
if (!doc.load("<node id='123'>text</node><!-- comment -->", pugi::parse_default | pugi::parse_comments)) return -1;
is hard-coded. Also I tried reading about xml_document and xml_node documentation but could not figure out how to start with if I have to build a tree from scratch.
#include "pugixml.hpp"
#include <string.h>
#include <iostream>
int main()
{
pugi::xml_document doc;
if (!doc.load("<node id='123'>text</node><!-- comment -->", pugi::parse_default | pugi::parse_comments)) return -1;
//[code_modify_base_node
pugi::xml_node node = doc.child("node");
// change node name
std::cout << node.set_name("notnode");
std::cout << ", new node name: " << node.name() << std::endl;
// change comment text
std::cout << doc.last_child().set_value("useless comment");
std::cout << ", new comment text: " << doc.last_child().value() << std::endl;
// we can't change value of the element or name of the comment
std::cout << node.set_value("1") << ", " << doc.last_child().set_name("2") << std::endl;
//]
//[code_modify_base_attr
pugi::xml_attribute attr = node.attribute("id");
// change attribute name/value
std::cout << attr.set_name("key") << ", " << attr.set_value("345");
std::cout << ", new attribute: " << attr.name() << "=" << attr.value() << std::endl;
// we can use numbers or booleans
attr.set_value(1.234);
std::cout << "new attribute value: " << attr.value() << std::endl;
// we can also use assignment operators for more concise code
attr = true;
std::cout << "final attribute value: " << attr.value() << std::endl;
//]
}
// vim:et
XML:
<?xml version="1.0" encoding="UTF-8"?>
<d:testrequest xmlns:d="DAV:" xmlns:o="urn:example.com:testdrive">
<d:basicsearch>
<d:select>
<d:prop>
<o:versionnumber/>
<d:creationdate />
</d:prop>
</d:select>
<d:from>
<d:scope>
<d:href>/</d:href>
<d:depth>infinity</d:depth>
</d:scope>
</d:from>
<d:where>
<d:like>
<d:prop>
<o:name />
</d:prop>
<d:literal>%img%</d:literal>
</d:like>
</d:where>
</d:basicsearch>
</d:testrequest>
I could see most of the examples posted on how to read/parse the xml, but I could not find how to create one from the scratch.

Answer 1

Please refer to the following section of the manual https://github.com/zeux/pugixml/blob/master/docs/manual.html#manual.modify.add and to the following sample code https://github.com/zeux/pugixml/blob/master/docs/samples/modify_add.cpp

Answer 2

Home page of pugixml gives sample code for building XML tree from scratch.
Summary: Use default constructor for pugi::xml_document doc, then append_child for the root node. Generally, a node is first inserted. The insertion call's return value then serves as a handle for filling the XML node.
Constructing xml tree