Linked Lists. CS2023 Winter 2004

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1 Linked Lists CS202 Winter 2004

2 Outcomes: Linked Lists C for Java Programmers, Chapter 11 (11.4.9) and C Programming - a Modern Approach, Chapter 17 (17.5) After the conclusion of this section you should be able to Write modules using linked lists Begin creating other similar data structures, such as trees

3 Linked Lists Chain of structures (nodes) each containing pointer to next node in chain More flexible than array easily insert/delete nodes but lose random access to elements accessing node fast if node is close to the beginning, but slow if node is near the end of the list

4 # $ Declaring a Node Type to improve maintainability of code: Define must use structure tag "! if there is no next % % will be The value of element, otherwise it will be a structure representing the next element.

5 & -. 4 ',+ 1 0/ ' 1 6 0/ Declaring a Node Type Need variable that always points to first node in list (C for Java Programmers uses another structure to do this): 45 )* '( initialized to initially empty to indicate that list is

6 <; :=? K K K ; B A := B B F G ED C K M M L7 OP O ON? C C X W Creating Nodes 1. Allocate memory for the node 2. Store data in the node. Insert the node into the list 1. Need variable to point to the node temporarily: 9 : 78 9: 78 Allocate memory for the new node: 9 : BH F 8 9 : 7 8 V R QSU T QSR _ \^ ] \ Y[Z

7 d a ` i n a ` l d df e m t s w vu { r Creating Nodes 2. Store data in the bjc member of the new node: oqp b c dkj gh z v xsy }[~. Insert node into list inserting in at beginning of list is easiest

8 ƒ Ž ƒ Œ ƒ Ž Ž ƒ Inserting Node at Beginning of List 1. Modify the new node's member to point to the node that was previously at beginning of list: Š ˆ 2. Make point to the new node: Š ˆ

9 Ÿ œ ž š Ÿ ž Inserting Node at Beginning of List º ¹ [ ªS«µ ³ [± º ¹ ªS«µ ³ [± 1. 2.

10 ÃÂ ¼» Á ÔÓ ¼» Î Á Ï Ø Inserting Node at Beginning of List Add another node: ÍÊÎ Í Ì À ¼ ¾[ Æ Ë ¼ ÈÊÉ ÆkÇ Å Ä Ä À ¼ ¾[ ½ ¼ ÄÊÒ Ã ÐÑ À ¼ ¾[ ½ Ö Õ Û ÚÙ Ö Ü â Þ àsá ß ÞÝ

11 îï ì ë ñð äã í é õö îï ì ñð äã í õö Inserting Node at Beginning of List Insert new node at beginning of list ì ò è ä äã ê æ[ç å ô ó ù ø ô ú ü þsÿ ý üû ò è ä æ ç å ô ó ù ø ô ú ü þsÿ ý üû

12 # #$ '& + + $ $ Inserting Node at Beginning of List "! %* ' ) % (,-,.

13 Inserting Node at Beginning of List / /0 21 ;: < / /0 21 ;: A How to get B C ED F G H IF C G to update JK ML N directly, rather than return a new value of OP RQ S? T U WV VYX [Z \ ] ^ \ XU ] _` U W [ ba c V \ Z ];d egf ] f aih [j W k l ` U W [ ba f nm o V c f nm p fq r r su _ Z V@t [ U c _` U W [ a k k k p p ` vu v k [ n V ] _w yx a z {^ y v u w k o f nm } ~ T f r m [ p W o f nm } ~X [ n ] p c V \ Z ] o c V \ Z ] p f nm o

14 ƒ ˆ ƒ Š ˆ Ž œ š ƒ Ž ˆ ž ˆ š ƒ œ Ÿ œ š ª œ š ª œ š Inserting Node at Beginning of List Recall that pointers, like other arguments, are passed by value. Need to pass a pointer to ƒ Ž Š ˆ Œ ƒ i g ˆ Ž ƒ Ÿ Ÿ ˆ Œ š «ƒ Š «ƒ»@¼ º ¹ ; ± µ ± ³ ± Y Call:

15 Ñ Å ½Ã ÊÉ È ÏÐ Á Á Ä Â Â Ì Ò ÙØ Ú Û ò ñ è í áà áà ð ßï å äã ßâ áà ïó ñ é ù ê õ ï ï ï ô ô ô ñ ê ð ïó ð ð Searching a Linked List Idiom for traversal of a list: ÍÎ Ë Æ Ë ÅÇÆ ÀYÁ ½@¾ Á Â ). Öi Search a list for data n (of type return pointer to node containing n, Õ Ô ÓgÔ otherwise return null pointer: àiî ã é ã è ä ë Þ ß ÜgÝ ê é â æç é;ì â ÞYß ÜgÝ ÞYß ÜgÝ ßð ø ó ç ç öü é ó â è ä ë ë Ý ä ïi ß û@ü ã ë è øú ô ô ïi ä é ü ß ä ó ç ç öü ä é ü ß ä ý

16 þÿ &!! % Searching a Linked List passed by value, can modify it: Since $# " () %'!! # ) " ) *

17 .. /7 =1 < D = 5 I H G E E A D JB L 9 K =J G 1 5 =1 < Deleting a Node from a Linked List 1. Locate the node to be deleted 2. Alter previous node so that it bypasses deleted node. Call node +-, to reclaim space occupied by deleted 1. Need pointer to previous node as well as current node: ACB 9;: 24 /-0 1F 1 F 1 : B

18 s t U OP NM OT OT V Q Q Deleting a Node from a Linked List h qr op hn vu d c d e k j gih f d l d m UZY RS N WX RS 2. a-b \ ` ^4_ ] ] [-\.

19 Ž { { ~ Œ z { w w Œ ~ w š ~ Œ xœ Œ Œ š ƒ w ~ xœ Œ Œ ~ ~ š ƒ z xœ x z Œ ~ zœ Œ {Š ~ ˆ y x y z ÿ z z ~ ƒ y z w x ƒ x ~ z } z ÿ z ÿ z ~ ÿ z wx z z ƒ ~ x z } zœ z ƒ š œ ~ ƒ ~ z ƒ š ƒ z ~ zœ ƒ ƒ š x Œ } z ~ zœ z z z ~ ƒ ~ z ž wx

20 Ÿ ³ «¹» Deleting an Entire Linked List 1. Remove all nodes one at a time from the beginning of the list 2. Set pointer to first element to null. «± ª «µ ± ª ª º ± ÈÉ ¾ Ä À Ç ÅÆ ¾ Ä Ã Â Á À ¾ ¼½ Call:

21 ÊË Ì ÍÎ Ï Î Ì Î Ð ÊÑ Ò Ì ÓÔ Õ ÍÎ Ö Ø Ù ÊÑ Ò ÌÚ Û Ü Ô Õ ÍÎ Ö ÝÞ ß à Ø Ù ÊÑ Ò ÌÚ á Ê Ù Ó ÝÞ ß à à Ô ãâ ã Û ä Ø Î Úå Ìçæ Ï Ê Ò Ì Ø ä Ñ Î Ì Þ Ñ Ë è á Ø Ù ÊÑ Ò ÌÚ à ÝÞ ßé êë Î ß Ì á Ù Ñ Î Î Ó ÝÞ ß Û á Ñ Î Ì Þ Ñ Ë ë á ì Deleting the First Node

22 í î ï ð ñ Ordered Lists Searching is faster than unordered linked list can stop after reaching point where desired node would have been located Inserting a node is more difficult Illustrate using a parts database see C Programming: a Modern Approach, p. 79

23 ý ò õô ú õ ö ò ÿ ò ò "# Parts Database ò û ú òù ø ö õ ù üô òçó õ ù ÿ ò þÿ ü ÿ ü ù û ü ÿ þÿ ÿ õ ù üô ò û ú òù ø ò ü ù ò ü ù þ ÿ ò ó ù ò ÿ õ ü ù is a global variable)! (here

24 & & %$ /.1 + * ', + * * /2 / Find Part in Inventory Look up a part number in inventory and return pointer to node containing part number. If not found, return ')( ')(

25 :9 AB J CF C K LM B E L O TS R W CF L O J? Z W IC L O M A J E B TS R CF L O LM I TS I Find Part in Inventory ; ; Look up a part number in inventory and return pointer to node containing part number. If not found, return HI G? C BE? <)= D <)= <)=? N C A8N Q M I CP H I G HI G V V U U M CF W LYX LYX H I G H I G V V U U CF W LYX O O C? F U M U C? F [

26 _^ ] \ fe _^ d cb a` i g8h ] \ Prompt user for part number then look it up in inventory. If part exists, print name and quantity; if not, print an error message

27 u ml ts ml r qp on v qp } t x q w t u u w t x qp } ˆ v Š ˆ u t x q ƒ u m wp l x t x q ƒ on o m t x q Prompt user for part number then look it up in inventory. If part exists, print name and quantity; if not, print an error message k j k j { o q z y w x lw } ~ x u ƒ { o q z y w x x o q lw qp { o q z y m w wp r n { o q z y m lw u Œ Œ t l w w n w x qp } lw oz p YŽ oz p w m wk x lw Ž wp y u w x k w x qp } lw wy k

28 Ÿ š œ 8!ž Prompt user for part number. Print error message if part doesn't exist; otherwise prompts user to enter change in quantity and updates the inventory

29 «µ ¹ ¼ ª ¾ ³ ¹ Â ÅÄ Ã Â ¼ ª «µ ª µ Á «³ Ë «µ Î Í « ¹ ª Prompt user for part number. Print error message if part doesn't exist; otherwise prompts user to enter change in quantity and updates the inventory ª!«± «ª ³ ¹ º ª ± «¼» ª ª!«½ ± «¼ À ¼» Á µ ± «ª» Æ Æ» ª!«½) ¼» ª È ¾ Ç ¼ À ¼» µ Â Ì Ê ŸÉ ¼ Ï ª ª ¼» Í

30 ÓÒ Ñ Ð Ú Ù Ø ÓÒ Ñ Ð Ö Insert Part in Inventory Prompts user for information about a new part and then inserts it into the inventory list. The list remains sorted by part number ÛÝÜ ÒÕÔ

31 è áà ç æ å áà äã é ä á ß ô ó îï å õ ç ä á ß ô ó å ß ë õ ö é ûô ä á ß ô ó è ý æ â äã õ õ âå äå Insert Part in Inventory Prompts user for information about a new part and then inserts it into the inventory list. The list remains sorted by part number àõâ ß Þ ß Þ ê í æ êìë ä â äå ò Þ ð åñð è è í æ ê ë ç ú ä àýù ã ø ø î ß ä â è ü ü ç â ä ú à ö ö ø ø ú ï ú à ÿ ë ýç ú æ ë þ ë à â å ò æ ï

32 & $ # # & ( # ) $ & ( # * )! ' ' $ " % ' '!!!! # # ' '! # #! -, + %.

33 <6 45 8: 2 = ; 7G FA 8: = C E H < / = ; 45 < = C E S = C U = W 8 S = C U / 0/ A < 7? ? D M B LK 2 9 IJ A 6 8 6P 2 R 9 DB 2 Q ON 8 0 J O T D2 8 A 8 2 <?? VA / T T 8 A B 0 K T 2 8U 8 A 8 2 T D2 8 8 N8/0 X

Professional Liability Errors and Omissions Insurance Application

Professional Liability Errors and Omissions Insurance Application If coverage is issued, it will be on a claims-made basis. Notice: this insurance coverage provides that the limit of liability available to pay judgements or settlements shall be reduced by amounts incurred