linked list: traversal insertion deletion. linked list traversal lb
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Linked List: Traversal InsertionDeletion
Linked List Traversal
LB
Linked List Traversal
• Traversal means “visiting” or examining each node.
• Simple linked list– Start at the beginning– Go one node at a time until the end
• Recursive procedure (or function)– Given a head pointer– Looks at just one node– What procedure will look at the rest?
LB
The Node Code
Node definesa record
data isoftype Num
next isoftype Ptr toa Node
endrecord
LB
The Big Picture
42
heap
stackhead
98 12 6
LB
The Little Picture
12
LB
The Classic Code
Procedure Traverse
(current isoftype in Ptr toa Node)
// Precon: Pass in pointer to a list
// Purpose: Print each data item
// Postcon: No changes to list
if(current <> NIL) then
print(current^.data)
Traverse(current^.next)
endif
endprocedure // Traverse
LB
The Big Picture
42
heap
stackhead
98 12 6
LB
Questions?
LB
Insertion Into Linked Lists
Node Definition
node definesa record
data isoftype Num
next isoftype ptr toa node
endrecord
The Scenario
• You have a linked list– Perhaps empty, perhaps not– Perhaps ordered, perhaps not
• You want to add an element into the linked list
48 17 142head //
Adding an Element to a Linked List
Involves two steps:
• Finding the correct location
• Doing the work to add the node
Finding the Correct Location
• Three possible positions:– The front– The end– Somewhere in the middle
head
Inserting to the Front
• There is no work to find the correct location
• Empty or not, head will point to the right location
48 17 142head 93
Inserting to the End
• Find the end of the list(when at NIL)
– Recursion or iteration
48 17 142head //93 //
Don’t Worry!
Inserting to the Middle
• Used when order is important
• Go to the node that should follow the one to add
– Recursion or iteration
17 48 142head //93 //142
The Work to Add the Node
• Create the new node• Fill in the data field• Deal with the next field
– Point to nil (if inserting to end)– Point to current (front or middle)
temp <- new(Node) temp^.data <- new_data temp^.next <- current current <- temp
Three Types of Insertion
• To front– No recursion needed
• To end– Get to the end, then add node
• In order (in middle)– To maintain sorted property
Inserting at the Front of a Linked List
Inserting to the Front of a Linked List
• Need an in/out pointer parameter
• Create new node• Fill in data• Make new node’s next pointer point to
current• Update current to point to new node
procedure Insert (current iot in/out ptr toa Node, new_data isoftype in Num)
temp isoftype ptr toa Node temp <- new(Node) temp^.data <- new_data temp^.next <- current current <- tempendprocedure
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Current new_data temp2R
2
Animated Insert to Front of Linked List
(current iot in/out ptr toa Node,
temp <- new(Node)temp^.data <- new_datatemp^.next <- currentcurrent <- temp
Inserting at the End of a Linked List
Inserting to End of a Linked List
• Recursively traverse the list until at end• Then:
– Create new node at current– Fill in data– Terminate the new node’s
next pointer to point to NIL
Inserting to the End of a Linked List
procedure Add_To_End( current isoftype in/out Ptr toa Node, new_data isoftype in Num )
// Purpose: Add new node to end of list
// Pre: current points to NIL-terminated list
// Post: new list has added element at end
if( current = NIL ) then
current <- new( Node )
current^.data <- new_data
current^.next <- NIL
else
Add_To_End( current^.next, new_data)
endif
endprocedure //Add_To_End
48 17 142head 53
current new_data 53R
current new_data 53R
current new_data 53R
current new_data 53R
Inserting at the End of a Linked List
Inserting in Order into a Linked List
Inserting In Order into a Linked List
• Recursively traverse until you find the correct place to insert– Compare to see if you need to insert before
current– If adding largest value, then insert at the end
• Perform the commands to do the insertion– Create new node– Add data– Update the next pointer of the new node– Update current to point to new node
Inserting in Order into a Linked List
procedure Insert_In_Order(current isoftype in/out Ptr toa Node, new_data isoftype in Num )
// comments here temp isoftype Ptr toa Node if ((current = NIL) OR (current^.data > new_data)) then temp <- new( Node ) temp^.data <- new_data temp^.next <- current current <- temp else Insert_In_Order(current^.next,new_data) endifendprocedure //Insert_In_Order
13 18 23Head
Inserting In Order into a Linked List
19
current new_data tempR 19
current new_data tempR 19
current new_data tempR 19
Summary
• Inserting into a linked list involves two steps:– Find the correct location– Do the work to insert the new value
• We can insert into any position– Front– End– Somewhere in the middle
(to preserve order)
Questions?
Deleting an Element from a Linked List
The Node Definition
Node definesa record
data isoftype num
next isoftype ptr toa Node
endrecord
The Scenario
• Begin with an existing linked list– Could be empty or not– Could be ordered or not
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head
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The Scenario
• Begin with an existing linked list– Could be empty or not– Could be ordered or not
4 17
head
426
The Scenario
• Begin with an existing linked list– Could be empty or not– Could be ordered or not
4 17
head
42
The Scenario
• Begin with an existing linked list– Could be empty or not– Could be ordered or not
4 17
head
42
Finding the Match
• We’ll examine three situations:
– Delete the first element
– Delete the first occurrence of an element
– Delete all occurrences of a particular element
Deleting the First Element
• This can be done without any traversal/searching• Requires an in/out pointer
procedure DeleteFront(current iot in/out ptr toa Node)
// deletes the first node in the list if (current <> nil) then current <- current^.next endifendprocedure
Deleting from a Linked List
• Deletion from a linked list involves two steps:– Find a match to the element to be deleted
(traverse until nil or found)– Perform the action to delete
• Performing the deletion is trivial:
current <- current^.next– This removes the element, since nothing will
point to the node.
4 17
head
426
.
.Delete(head, 4)..
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
4 17
head
426
Target = 4
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
4 17
head
426
Target = 4
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
4 17
head
426
Target = 4
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
4 17
head
426
Target = 4
.
.Delete(head, 4)..
4 17
head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
4 17
head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
4 17
head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
4 17
head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
4 17
head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
4 17
head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
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head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
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head
426
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete single occurrence of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
.
.Delete(head, 4)..
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head
426
Linked List Deletion(All Occurrences)
Deleting All Occurrences
• Deleting all occurrences is a little more difficult.
• Traverse the entire list and don’t stop until you reach nil.
• If you delete, recurse on current• If you don’t delete, recurse on
current^.next
4 17
head
46
.
.Delete(head, 4)..
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
4 17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
46
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
procedure Delete(cur iot in/out ptr toa Node, target isoftype in num)
// Delete all occurrences of a node. if(cur <> NIL) then if(cur^.data = target) then
cur <- cur^.next Delete(cur, target) else
Delete(cur^.next, target) endif endifendprocedure
Target = 4
17
head
6
.
.Delete(head, 4)..
Summary
• Deletion involves:– Getting to the correct position– Moving a pointer so nothing points to
the element to be deleted
• Can delete from any location– Front– First occurrence– All occurrences
Questions?
top related