1. Linked List - I

2. Abstract Data Type (ADT) ADT is a data type whose properties (domain and operations) are specified independently of any particular implementation. –Logical (or ADT) level: abstract view of the domain and operations. –Implementation level: specific representation of the structure to hold the data items, and the coding for operations.

3. 4 Basic Kinds of ADT Operations Constructor/Destructor – creates/deletes a new instance (object) of an ADT. Transformer -- changes the state of one or more of the data values of an instance. Observer -- allows us to observe the state of one or more of the data values of an instance without changing them. Iterator -- allows us to process all the components in a data structure sequentially.

4. List Linear relationship Each element except the first has a unique predecessor, and each element except the last has a unique successor. Length The number of items in a list; the length can vary over time.

5. Class ShoppingList class ShoppingList { public : intLengthIs ( ) const ; void RetrieveItem (int pos) ; void InsertItem (const Item& item, int pos ) ; void RemoveItem (int pos); void DeleteAll ( ); private : int size ; Node*front ; } ;

6. Singly Linked List Diagram Pointer to front node ABC NULL Nodes Data carried in nodePointer to next node

7. Class Node A Item item;Node *link; class Node { public: Node(Item i){item = i}; private: Item item; Node *link; }; Insert an item/node into shopping list? Delete an item/node?

8. Front Insert Example (1 of 6) front ABC itemlinkitemlinkitemlink prevcurpos 0 anItem D ?? void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, //ignore prev ptr for the FrontInsert example *cur; Inserting D at position 0 size 3

9. Front Insert Example (2 of 6) front ABC itemlinkitemlinkitemlink curpos 0 anItem D ? assert(pos >= 0 && pos <= size); size++; size 4

10. Front Insert Example (3 of 6) front ABC itemlinkitemlinkitemlink curpos 0 anItem D if (pos == 0) { // Inserting at the front cur = front; size 4

11. Front Insert Example (4 of 6) front ABC itemlinkitemlinkitemlink curpos 0 anItem D front = new Node(anItem); size 4 D itemlink ?

12. Front Insert Example (5 of 6) front ABC itemlinkitemlinkitemlink curpos 0 anItem D front->link = cur; size 4 D itemlink

13. Front Insert Example (6 of 6) front ABC itemlinkitemlinkitemlink return; } size 4 D itemlink

14. Empty Insert Example (1 of 6) size curpos 0 anItem A ? void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, //ignore prev for EmptyInsert example *cur; Inserting A at position 0 in empty list front 0

15. Empty Insert Example (2 of 6) size curpos 0 anItem A ? assert(pos >= 0 && pos <= size); size++; front 1

16. Empty Insert Example (3 of 6) size curpos 0 anItem A if (pos == 0) { // Inserting at the front cur = front; front 1

17. Empty Insert Example (4 of 6) size curpos 0 anItem A front = new Node(anItem); front 1 A itemlink ?

18. Empty Insert Example (5 of 6) size curpos 0 anItem A front->link = cur; front 1 A itemlink

19. Empty Insert Example (6 of 6) size return; } front 1 A itemlink

20. Middle Insert Example (1 of 8) void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, *cur; Inserting D at position 2 front ABC itemlinkitemlinkitemlink prevcurpos 2 anItem D ?? size 3

21. Middle Insert Example (2 of 8) assert(pos >= 0 && pos <= size); size++; front ABC itemlinkitemlinkitemlink prevcurpos 2 anItem D ?? size 4

22. Middle Insert Example (3 of 8) prev = NULL; cur = front; front ABC itemlinkitemlinkitemlink prevcurpos 2 anItem D size 4

23. Middle Insert Example (4 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; } First Iteration front ABC itemlinkitemlinkitemlink prevcurpos 1 anItem D size 4

24. Middle Insert Example (5 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; } Second Iteration front ABC itemlinkitemlinkitemlink prevcurpos 0 anItem D size 4

25. Middle Insert Example (6 of 8) prev->link = new Node(anItem); front ABC itemlinkitemlinkitemlink prevcurpos 0 anItem D size 4 D ? itemlink

26. Middle Insert Example (7 of 8) prev->link->link = cur; front ABC itemlinkitemlinkitemlink prevcurpos 0 anItem D size 4 D itemlink

27. Middle Insert Example (8 of 8) } front ABC itemlinkitemlinkitemlink size 4 D itemlink

28. End Insert Example (1 of 8) void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, *cur; Inserting D at position 3 front ABC itemlinkitemlinkitemlink prevcurpos 3 anItem D ?? size 3

29. End Insert Example (2 of 8) assert(pos >= 0 && pos <= size); size++; front ABC itemlinkitemlinkitemlink prevcurpos 3 anItem D ?? size 4

30. End Insert Example (3 of 8) prev = 0; cur = front; front ABC itemlinkitemlinkitemlink prevcurpos 3 anItem D 0 size 4

31. End Insert Example (4 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; } First Iteration front ABC itemlinkitemlinkitemlink prevcurpos 2 anItem D size 4

32. End Insert Example (5 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; } Second Iteration front ABC itemlinkitemlinkitemlink prevcurpos 1 anItem D size 4

33. End Insert Example (6 of 8) while (pos > 0) { prev = cur; cur = cur->link; pos--; } Third Iteration front ABC itemlinkitemlinkitemlink prevcurpos 0 anItem D size 4

34. End Insert Example (7 of 8) prev->link = new Node(anItem); prev->link->link = cur; front ABC itemlinkitemlinkitemlink prevcurpos 0 anItem D size 4 D itemlink

35. End Insert Example (8 of 8) } front ABC itemlinkitemlinkitemlink size 4 D itemlink

36. void ShoppingList::insert(const Item & anItem, int pos) { Node *prev, *cur; assert(pos >= 0 && pos <= size); size++; if (pos == 0) { // Inserting at the front cur = front; front = new Node(anItem); front->link = cur; return; } prev = NULL; cur = front; while (pos > 0) { prev = cur; cur = cur->link; pos--; } prev->link = new Node(anItem); prev->link->link = cur; }

37. Remove Example (1 of 7) void ShoppingList::remove(int pos) { Node *cur, *prev; Removing at position 1 front ABC itemlinkitemlinkitemlink prevcurpos 1 ?? size 3

38. Remove Example (2 of 7) assert(pos >= 0 && pos < size); size--; front ABC itemlinkitemlinkitemlink prevcurpos 1 ?? size 2

39. Remove Example (3 of 7) prev = NULL; cur = front; front ABC itemlinkitemlinkitemlink prevcurpos 1 size 2

40. Remove Example (4 of 7) while (pos > 0) { prev = cur; cur = cur->link; pos--; } front ABC itemlinkitemlinkitemlink prevcurpos 0 size 2 First iteration Delete the node pointed by cur

41. Remove Example (5 of 7) prev->link = cur->link; front ABC itemlinkitemlinkitemlink prevcurpos 0 size 2

42. Remove Example (6 of 7) delete cur; front ABC itemlinkitemlinkitemlink prevcurpos 0 size 2

43. Remove Example (7 of 7) } front AC itemlinkitemlink size 2

44. Delete All Example (1 of 8) void ShoppingList::deleteAll() { Node *kil; front ABC itemlinkitemlinkitemlink kil ? size 3

45. Delete All Example (2 of 8) while (front != NULL) { kil = front; front = front->link; ABC itemlinkitemlinkitemlink kil frontsize 3 First iteration

46. Delete All Example (3 of 8) kil->link = NULL; delete kil; } ABC itemlinkitemlinkitemlink kil frontsize 3 First iteration

47. Delete All Example (4 of 8) while (front != NULL) { kil = front; front = front->link; BC itemlinkitemlink kil frontsize 3 Second iteration

48. Delete All Example (5 of 8) kil->link = NULL; delete kil; } BC itemlinkitemlink kil frontsize 3 Second iteration

49. Delete All Example (6 of 8) while (front != NULL) { kil = front; front = front->link; C itemlink kil frontsize 3 Third iteration

50. Delete All Example (7 of 8) kil->link = 0; delete kil; } C itemlink kil frontsize 3 Third iteration 0

51. Delete All Example (8 of 8) size = 0; } frontsize 0