Week 08 Notes for CS 2500, Section 001 -- Spring 2002

• Look at Upcoming Schedule
• Class starts at 09:40. I take roll at 09:50
• Announcement(s)
  • I posted results of grading program #2 and an updated comprehensive gradesheet.
  • I put charts describing a possible design of the cashier program in the class web space. Members of the class may refer to it while designing their programs.
• Discuss how the list operations are implemented in the array-based case by examining the code in the ListA.cpp file.
• Discuss how linked lists work.
  • Refer to the ListP.h header file.
  • Refer to the ListP.cpp implementation file.
  • The interface to our linked list (see ListP.h) is the same as the interface to our array list (see ListA.h). This is a case where the ADT remains the same. It is only the implementation that differs.
  • In ListP.h note what is different from ListA.h.
  • Look at the diagrams illustrating insertion into a linked list and retrieval from a linked list. Use these diagrams to get a feel for how linked lists are implemented.
  • Discuss the code in the ListP.cpp implementation file. Note how the following things are used:
    • pointers,
    • linking,
    • calls of the form "new dataType" to allocate memory dynamically, and
    • calls of the form "delete pointerToData" to deallocate (recycle) dynamically allocated objects.
  • Consider how an element is removed from a linked list.
  • Review the pro's/con's and performance differences between pointer-based and array-based implementations.
    • Arrays are easy to use, but they have a fixed size.
    • A program that uses an array may run out of memory or waste storage.
    • Using dynamic arrays may waste time and/or storage.
    • An array-based implementation does not require extra storage for pointers.
    • A program can access array items quickly (random access).

• Look at Upcoming Schedule
• Class starts at 09:40. I take roll at 09:50
• Announcement(s)
• Discuss what the header comments for program #2 should have said.
• finish up discussing linked lists
  • the destructor: ~listClass
  • ListRetrieve
  • the copy constructor: listClass(const listClass&)
    • what does it do?
    • how do you call it?
• If time allows, begin discussing applications of the stack data type
  • Evaluating postfix expressions
  • "Towers of Hanoi" puzzle program
  • depth-first search