CMSC 202 Computer Science II, Spring 2016, Section 01

Lecture 18: Polymorphism

Tue 04/05, 2016

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Assigned Reading: 

Slides As Shown:

• Virtual Member Functions : [slide view] [print view]

• Generic Sorting: [slide view] [print view]

• A Heterogeneous Linked List: [slide view] [print view]

Topics Covered:

• Reviewed for Midterm Exam II.
• Dynamic binding and virtual member functions.

• Used virtual member functions to design an abstract Array base class with a sorting function. Any class derived from array can be sorted using sort() without recompiling the base class functions.

  • Base class Array header and implementation: Array.h, Array.cpp.
  • Derived class IntArray for integers: IntArray.h IntArray.cpp
  • Derived class FloatArray for integers: FloatArray.h FloatArray.cpp
  • Main program and sample output: main1.cpp, main1.txt,

• A hetergeneous linked list can hold different types of objects in the list at the same time. The implementation of HList brings up many issues that come up when you work with virtual functions, including:
  • the need for a virtual destructor
  • clone(): a virtual "copy constructor"
  • run-time type information
  • dynamic type casting

• Code for HList and the HNode base class: HList.cpp, HList.h.

• IntNode class derived from HNode: IntNode.cpp, IntNode.h.

• Test program #1 and output: HLtest1.cpp, HLtest1.txt.

• DoubleNode class derived from HNode: DoubleNode.cpp, DoubleNode.h.

• StringNode class derived from HNode: StringNode.cpp, StringNode.h.

• Test program #2 and output: HLtest2.cpp, HLtest2.txt.

• Test program #3 and output: HLtest3.cpp HLtest3.txt

• HStack is a private derivation of HList. HStack.cpp, HStack.h, HStack2.h.

• Stack tested: HStest1.cpp, HStest1.txt.

• FIFO queue implemented. Check out source code for HQueue. HQueue.cpp, HQtest1.cpp, HQtest1.txt, HQueue.h.