I'm interested in how a sequence of integers can be shown by a function and some subclasses that sum the terms, of non-negative integers as...

I'm interested in how a sequence of integers can be shown by a function and some subclasses that sum the terms, of non-negative integers as parameters and returns the sequence. The C++ abstract class AbstractSeq should have a virtual member function as a representation of the sequence and two-member functions printSeq and sumSeq.