This coding project is to demonstrate the use of modern C++ standard
as well as unit tests in implementation and verification of GENERAL TREE.
Which outputs (possibly):
Empty container
P, K, P, N, H, U, P, O, O, A,
Highest value element: U
The data structure has been tested by implementing CppUnit test cases.
Doxygen tool has generated the documentation relying on the configuration file
and multi-line comments.