extract data using c++ and store in txt - c++

Question

I have a text file with the following data format
<create>
<way id="-200341" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-106862"/>
<nd ref="-106343"/>
<nd ref="-107240"/>
<nd ref="-107241"/>
<nd ref="-106863"/>
<nd ref="-106858"/>
<nd ref="-106866"/>
<nd ref="-106263"/>
<nd ref="-106868"/>
<nd ref="-106857"/>
<nd ref="-107242"/>
<nd ref="-106867"/>
<nd ref="-106865"/>
<nd ref="-107243"/>
<nd ref="-107244"/>
<nd ref="-106864"/>
<tag k="shelter" v="yes"/>
<tag k="highway" v="footway"/>
</way>
<way id="-200340" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-106853"/>
<nd ref="-106852"/>
<tag k="shelter" v="yes"/>
<tag k="highway" v="footway"/>
</way>
<way id="-200277" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-106228"/>
<nd ref="8236806130"/>
<tag k="highway" v="footway"/>
</way>
<way id="-200253" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-106766"/>
<nd ref="-106765"/>
<nd ref="-106226"/>
<nd ref="-106769"/>
<nd ref="-106228"/>
<nd ref="-106773"/>
<nd ref="-106230"/>
<nd ref="-106771"/>
<nd ref="-106768"/>
<tag k="highway" v="footway"/>
<tag k="shelter" v="yes"/>
</way>
<way id="-200219" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-107148"/>
<nd ref="-106747"/>
<tag k="shelter" v="yes"/>
<tag k="highway" v="footway"/>
</way>
<way id="-200218" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-106766"/>
<nd ref="-106755"/>
<tag k="shelter" v="yes"/>
<tag k="highway" v="footway"/>
</way>
<way id="-200066" version="0" timestamp="1970-01-01T00:00:00Z">
<nd ref="-106755"/>
<nd ref="-107148"/>
<nd ref="-106760"/>
<nd ref="-106764"/>
<nd ref="-106762"/>
<nd ref="-107115"/>
<nd ref="-106197"/>
<tag k="highway" v="footway"/>
<tag k="shelter" v="yes"/>
</way>
<way id="543558082" version="1" timestamp="2017-11-29T19:30:02Z" uid="0" user="">
<nd ref="1314909074"/>
<nd ref="5254615443"/>
<nd ref="5254615442"/>
<nd ref="5254615441"/>
<nd ref="5254615440"/>
<nd ref="-106516"/>
<nd ref="5254615439"/>
<nd ref="5254615438"/>
<nd ref="5254615437"/>
<nd ref="5254615436"/>
<nd ref="5254615435"/>
<tag k="service" v="driveway"/>
<tag k="highway" v="service"/>
<tag k="oneway" v="yes"/>
</way>
I have a unordered_map std::unordered_map<int, std::string> uMapID_feats{}; declared like this.
Assuming that my map has all of these ID numbers ref="XXXXX" numbers stored, and a defaulted string stored in it, like "unknownplace".
what I want to do is map the ID (called "ref=XXXXXX") to the tags that are listed under it. So the tags eg. for the first ID ref=106862, the tags that are connected to it are 200341, shelter, highway, footway, yes
So in the map, the first 3 pairs would look like this:
"106862" , "200341,shelter,highway,footway,yes"
"106343" , "200341,shelter,highway,footway,yes"
"107240" , "200341,shelter,highway,footway,yes"
Some sets have more tags than others and some have only 2 tags, hence why I would like it all to be written to a string and stored in this unordered_map, the tags separated by commas.
How should I go about parsing this data and getting it stored in the unordered_map correctly?
any help is appreciated, thank you!

Answer 1

Use an xml parsing Library like plugixml, or you could build your own one.
There are many libraries which parses xml. Chose the one which fits your needs.
This may help you: What XML parser should I use in C++?