Lecture 31

intcell_des.h is the header file for a variation on our earlier intcell class.
This version adds a destructor method. incell_des.cpp is the implementation of
of the IntCell class defined in intcell_des.h. intcell_des_tester.cpp is the
code that tests the IntCell class.

assert_ex.cpp is a small demonstration of how the c assert statement works.