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Deletion Opration in Linked List for Data Structure in C Programming

Deletion
Removing a node from the linked list is called deletion. Get the Information of the node, which is to be     removed. Compare the Information with the INFO of ROOT . If it is equal update ROOT with LINK of ROOT, otherwise set pervious location PLOC with ROOT and location LOC with LINK of ROOT. Compare the information with that of INFO of LOC, if it is not equal then copy LOC in PLOC and update LOC with LINK of LOC. If the node is found then come out and set LINK of PLOC with LINK of LOC, and the deletion is over. Add the deleted node to Free Pool, by assigning LINK of LOC with AVAIL and AVAIL with LOC.
       If the PLOC is assigned with LOC, then when the list is traversed automatically the node with address LOC is skipped, that is why PLOC is used in this case.

         For example consider the below linked list:


       If a node with information 20 is to be deleted, the operation is done as shown below:


       The original list after deletion of the node with information 20 is shown e:


Algorithm to delete a node from the Linked List:

DELETIONLL(ROOT, INFO)
If INFO=ROOT-->INFO Then:
LOC<--ROOT
ROOT<--ROOT-->LINK
Else:
 PLOC<--ROOT
 LOC<--ROOT-->LINK
Repeat While LOC< >NULL AND INFO< >LOC-->INFO
 PLOC<--LOC
 LOC<--LOC-->LINK
[End of While]
PLOC--> LINK<-- LOC-->LINK
[End of If]
[Following statements to add deleted node to free pool]
 LOC-->LINK<--AVAIL
AVAIL<--LOC
Exit.


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Memory representation of Linked List Data Structures in C Language

Memory representation of Linked List

             In memory the linked list is stored in scattered cells (locations).The memory for each node is allocated dynamically means as and when required. So the Linked List can increase as per the user wish and the size is not fixed, it can vary.

               Suppose first node of linked list is allocated with an address 1008. Its graphical representation looks like the figure shown below:


      Suppose next node is allocated at an address 506, so the list becomes,



  Suppose next node is allocated with an address with an address 10,s the list become,


The other way to represent the linked list is as shown below:




 In the above representation the data stored in the linked list is “INDIA”, the information part of each node contains one character. The external pointer root points to first node’s address 1005. The link part of the node containing information I contains 1007, the address of next node. The last node …