Polymorphism, Virtual Functions, Abstract Base Class - Ch. 15

• Aggregation - The instance of a class within another class. "Has A" relationship
• Inheritance - A derived class will inherit all members of a base class. "Is A" relationship.
• Polymorphism - Allows a Base Class pointer or Base &reference variable to call the correct member functions, depending upon the type of object being referenced. "Many Things". Must be a Base Class pointer or Base &reference variable.
• Base Class Pointers - Pointers to a base class may point to derived class objects. ex. Base* base = new Base; Base* base = new Derived; Base* base = &baseObj; Base* base = &derivedObj;
• Virtual Functions
• Static Linking vs Dynamic Linking ("late binding")
• Abstract Base Class - An ABC is never instantiated, serves as a base class for derived. Represents generic or abstract form of all derived classes (Interface). Must contain at least one pure virtual member function.
• Pure Virtual Functions = 0; - Pure virtual functions have no body or definition within the base class. Must be overridden in a derived class.

GNU Debugger - GDB

• compile with -g flag to enable debugging information: g++ -g source.cpp -o exec
• Use -Wall to show all warnings: g++ -g -Wall source.cpp -o exec
• ulimit -c unlimited - allow a segFault create a core dump file
• gdb ./exec
• gdb ./exec core
• break - set break points at function or line number
• run
• step, s
• next, n
• continue, c
• info locals
• info args
• print variable
• print &variable
• print *ptr
• backtrace, bt
• frame #