Other List Structures

1. Other List Structures Reading: Chapter 8 Homework: p.403, #1, 2, 3; p. 448, #1, 3, 8, 10, 15

2. Design Alternatives • Consider alternative designs for the actual implementation of the list • For example, • array • singly linked list • doubly linked list • circular linked list • How would the choice be made? • Might it change in a later version?

3. Array-Based List item 1 item 2 item 3 item 4 item 5

4. Singly Linked List item 1 item 2 item 3 item 4 item 5 null

5. Doubly Linked List item 1 item 2 item 3 item 4 item 5 null null

6. Circular Linked List item 2 item 3 item 1 item 5 item 4

7. Head and Tail Pointers item 1 item 2 item 3 item 4 item 5 null

8. Lists Datatype • Interface should allow • creation of empty list • tests for empty • reinitialization to empty • access to front and back • insertion and removal • operators for moving iterator to beginning and end of list (begin() and end() );

9. STL List Constructors list<T> lst; Creates an empty list for elements of type T. list<T> lst(n, e); Creates list of n copies of e. list<T> lst(beg, end); Creates list with copies from range beg..end. lst.~list<T>(); Destroys all elems and frees memory.

10. STL List: Front/Back Push/Pop

11. STL List: Entire List Methods

12. Lists and Iterators • Stack object had member data defined to specify access points • Ok for stack since it allows only a single access point • Each container class is equipped with an associated iterator class. • Iterators maintain pointer to “current” element

13. Iterator • A pointer-like object • used to cycle through • all the elements stored in a container • // Built-in type • vector<int>::iterator p; • // Built-in values • p = v.begin(); • p != v.end()

14. List Iterator Datatype • Interface provides • Operators for moving iterator to beginning of list ( begin()) and end (end() ) • Operators for moving through the list (++ and --) • Operator for returning the current item on the list (*) • Generic algorithms (Find, Remove, etc.)

15. Traversing List using Iterator # include <list> list<int> L; L.push_back(0); L.push_front(1); L.push_back(2); L.sort(); list<int>::iterator itr; itr = L.begin(); while (itr != L.end()) { cout << *itr << " "; itr++; } // The values that are printed are 0 1 2

16. Adding Elements to a List

17. Erasing Elements from a List