Parsing an XML file, binary trees forest in C/C++

The task should use some of the following libraries RapidXml, Pugixml, Libxml, Boost and it'll be running on 64 bit Linux. On input there is an XML file contains a forest of binary trees (<Segment>) <Segment> <Node id="1"> <True/> <Node id="2"> <SimplePredicate field="data1" operator="lessOrEqual" value="1.162715515"/> <Node id="4"> <SimplePredicate field="data2" operator="lessOrEqual" value="1.0299651565"/> <Node id="8"> <SimplePredicate field="data3" operator="lessOrEqual" value="0.8254138555"/> <Node id="14" score="4"> <SimplePredicate field="data4" operator="lessOrEqual" value="-0.72156197"/> </Node> <Node id="15" score="-1.5"> <SimplePredicate field="data4" operator="greaterThan" value="-0.72156197"/> </Node> </Node> <Node id="9"> <SimplePredicate field="data3" operator="greaterThan" value="0.8254138555"/> <Node id="16" score="-10"> From stdin you get a string like this (it can be an array of arguments if it's easier to work with that) data1:val1,data2:val2,...datan:valn|data1:val1,data2:val2,...datan:valn.... The "|" character marks end of each input The program would go through each tree using each of the inputs and based on the data:value pair will end up in some node and store the value of score into an array. At the end it would print an average value of the array elements along with the input data. For example an input data1:1.08;data2:1.01;data3:0.66;data4:-0.6 will store -1.5 into an array In pseudocode the program might look like this input=readstdin; forest=readXMLfromfile; foreach_input{ foreach_forest{ arr[length]=runthrough(); } avg=countavg(arr); print "data1;data2;data3;...;avg\n"; }