INFSCI 0015 Data Structures Lecture 21: Linked Lists Implementation

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INFSCI 0015 - Data StructuresLecture 21 Linked
Lists Implementation

• Peter Brusilovsky
• http//www2.sis.pitt.edu/peterb/0015-011/

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Data Structures

• typedef struct
• int data
• struct node link
• NODE
• typedef struct
• int count
• NODE pos / for traverse /
• NODE head
• NODE rear
• LIST

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ADT Interface

• LIST createList ()
• LIST destroyList (LIST list)
• int addNode (LIST pList, int newdata)
• int removeNode(LIST pList, int d_data)
• static int retrieveNode(LIST pList, int key)
• int traverse (LIST pList, int from, int
  t_data)
• int listCount (LIST pList)
• int emptyList (LIST pList)
• int fullList (LIST pList)

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createList

• LIST createList()
• LIST list
• list (LIST ) malloc (sizeof (LIST))
• if (list)
• list-gthead NULL
• list-gtpos NULL
• list-gtrear NULL
• list-gtcount 0
• / if /
• return list
• / createList /

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(No Transcript)
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Service function _search

• int _search (LIST pList, NODE pPre, NODE
  pLoc, int s_data)
• 1 if greater than last node -- fail
• 2 move along the list while s_data gt
  (pLoc)-gtdata
• 3 if s_data (pLoc)-gtdata -- found
• 4 otherwise s_data lt (pLoc)-gtdata -- fail

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Service function _search (1)

• int _search (LIST pList, NODE pPre, NODE
  pLoc, int s_data)
• pPre NULL
• pLoc pList-gthead
• if (pList-gtcount 0)
• return 0
• / Test for argument gt last node in list /
• if ( s_data gt pList-gtrear-gtdata)
• pPre pList-gtrear
• pLoc NULL
• return 0
• / if /

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Service function _search (2)

• while ( s_data gt (pLoc)-gtdata )
• / Have not found search argument location /
• pPre pLoc
• pLoc (pLoc)-gtlink
• / while /
• if (s_data (pLoc)-gtdata)
• / argument found--success /
• return 1
• else / i.e., s_data lt (pLoc)-gtdata /
• return 0
• / _search /

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RetrieveNode with _search

• static int retrieveNode(LIST pList, int key)
• / Local Declarations /
• NODE pPre
• NODE pLoc
• / Statements /
• return _search (pList, pPre, pLoc, key)
• / retrieveNode /

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Service function _insert (1)

• static int _insert (LIST pList, NODE pPre, int
  newdata)
• NODE pNew
• if (!(pNew (NODE ) malloc(sizeof(NODE))))
• return 0
• pNew-gtdata newdata
• pNew-gtlink NULL
• if (pPre NULL)
• / Adding before first node or to empty list.
  /
• pNew-gtlink pList-gthead
• pList-gthead pNew
• if (pList-gtcount 0)
• / Adding to empty list. Set rear /
• pList-gtrear pNew

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Insert at the beginning of the list
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Service function _insert (2)

• else
• / Adding in middle or at end /
• pNew-gtlink pPre-gtlink
• pPre-gtlink pNew
• / Now check for add at end of list /
• if (pNew-gtlink NULL)
• pList-gtrear pNew
• / if else /
• (pList-gtcount)
• return 1
• / _insert /

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Insert in the the middle of the list
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addNode

• int addNode (LIST pList, int newdata )
• int found
• int success
• NODE pPre
• NODE pLoc
• found _search (pList, pPre, pLoc, newdata)
• if (found 1) / Duplicate /
• return (1)
• success _insert (pList, pPre, newdata)
• if (!success)
• / Overflow /
• return (-1)
• return (0)
• / addNode /

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Service function _delete

• void _delete (LIST pList, NODE pPre, NODE
  pLoc)
• if (pPre NULL)
• / Deleting first node /
• pList-gthead pLoc-gtlink
• else
• / Deleting any other node /
• pPre-gtlink pLoc-gtlink
• / Test for deleting last node /
• if (pLoc-gtlink NULL)
• pList-gtrear pPre
• (pList-gtcount)--
• free (pLoc)
• return
• / _delete /

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Delete first
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Delete General case
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destroyList

• LIST destroyList (LIST pList)
• NODE deletePtr
• if (pList)
• while (pList-gtcount gt 0)
• / Delete node /
• deletePtr pList-gthead
• pList-gthead pList-gthead-gtlink
• pList-gtcount--
• free (deletePtr)
• free (pList)
• / if /
• return NULL
• / destroyList /

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removeNode

• int removeNode(LIST pList, int d_data)
• / Local Declarations /
• int found
• NODE pPre
• NODE pLoc
• / Statements /
• found _search (pList, pPre, pLoc, d_data)
• if (found)
• _delete (pList, pPre, pLoc)
• return found
• / removeNode /

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Traversing list as ADT

• We need an extra pointer to store current
  position
• get_first will set pos head
• get_next will set pos pos-gtlink

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traverse (1)

• int traverse (LIST pList, int fromWhere, int
  t_data)
• int success
• if (fromWhere 0)
• /Start from first node /
• if (pList-gtcount 0)
• success 0
• else
• pList-gtpos pList-gthead
• t_data pList-gtpos-gtdata
• success 1
• / if else /

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traverse (2)

• else
• / Start from current position /
• if (pList-gtpos-gtlink NULL)
• success 0
• else
• pList-gtpos pList-gtpos-gtlink
• t_data pList-gtpos-gtdata
• success 1
• / if else /
• / if fromwhere else /
• return success
• / traverse /

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emptyList and listCount

• int emptyList (LIST pList)
• return (pList-gtcount 0)
• / emptyList /
• int listCount(LIST pList)
• return pList-gtcount
• / listCount /

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fullList

• int fullList (LIST pList)
• NODE temp
• if ((temp (NODE )malloc (sizeof (NODE))))
• free (temp)
• return 0
• / Dynamic memory full /
• return 1
• / fullList /

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Driver function (1)

• void main()
• LIST mylist
• int i, res
• int value
• mylist createList()
• while(1)
• printf("\nList manipulation\n\n")
• printf("1. Add\t\t")
• printf("2. Remove\n")
• printf("3. Find\t\t")
• printf("4. Empty\n")
• printf("5. Count\t")
• printf("6. Print\n")
• printf("7. End\n\n")

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Driver function (2)

• if(i 1)
• printf("Value? ")
• scanf("d",value)
• if((res addNode(mylist, value)) 0)
• printf("Value d added in\n", value)
• else if(res -1)
• printf("List is Full\n")
• else printf("Duplicate key d\n", value)
• else if (i 2)
• printf("Value? ")
• scanf("d",value)
• if(removeNode(mylist, value))
• printf("Node d removed\n", value)
• else printf("No node with key d\n", value)

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Driver function (3)

• else if (i 3)
• printf("Value? ")
• scanf("d",value)
• if (retrieveNode(mylist, value))
• printf("Node d found\n", value)
• else
• printf("Node d not found\n", value)
• else if (i 4)
• if (emptyList(mylist))
• printf("List is empty\n")
• else
• printf("List is not empty\n")

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Driver function (4)

• else if (i 5)
• printf("d elements in the list\n",
  listCount(mylist))
• else if (i 6)
• printf("( ")
• if (traverse(mylist, 0, value))
• do
• printf("d ", value)
• while (traverse(mylist, 1, value))
• printf(")\n")
• else
• destroyList(mylist)
• return