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Data Structure Linked List: Insertion and Deletion Operations in C

Learn how to insert and delete nodes in a linked list using single linked list techniques in C programming for Fall 2005 course agenda from W.F. Hu. Detailed steps include inserting at the beginning, middle, and end, along with how to delete nodes.

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Data Structure Linked List: Insertion and Deletion Operations in C

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  1. Fall 2005 Data Structure Linked List – Single Linked List

  2. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  3. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  4. Insert Node • Three steps to the insertion • Allocate memory for the new node and insert data • Point the new node to its successor. • Point the new node’s predecessor to it. W.F. Hu@ant.comm.ccu

  5. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  6. Insert into Empty List • Creat a new empty list : • Define the node’s structure • Creat a new empty list list_pointer ptr = NULL; typedef struct list_node *list_pointer; typedef struct list_node{ char data[4]; list_pointer link; } list_node; ptr NULL W.F. Hu@ant.comm.ccu

  7. Insert into Empty List • Insert a new node into empty list temp = (list_pointer) malloc (sizeof(list_node)); *ptr = temp; Address of first node ptr->data ptr->link NULL NULL ptr temp W.F. Hu@ant.comm.ccu

  8. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  9. Insert at Beginning (1/2) ptr 20 30 NULL 10 • Allocate memory for the new node and insert data temp Before insert After insert ptr 20 30 NULL 10 • Point the new node to its successor. • Point the new node’s predecessor to it. W.F. Hu@ant.comm.ccu

  10. Insert at Beginning (2/2) ptr 20 30 NULL 10 temp #include <stdlib.h> //page 141 #include <alloc.h> list_pointer temp; temp = (list_pointer) malloc (sizeof(list_node)); temp->data = 10; if(*ptr){ temp->link = *ptr; *ptr = temp; } else{ temp->link = NULL; *ptr = temp } W.F. Hu@ant.comm.ccu

  11. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  12. Insert in Middle (1/2) ptr 10 30 NULL Insert 20 between 10 and 30 20 temp W.F. Hu@ant.comm.ccu

  13. Insert in Middle (2/2) ptr 10 30 NULL node 20 temp void insert (list_pointer *ptr, list_pointer node) { if(*ptr){ temp->link = node->link; node->link = temp; } else{ temp->link = NULL; *ptr = temp } } W.F. Hu@ant.comm.ccu

  14. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  15. Insert at End ptr 10 20 NULL node void insert (…, …) { … if(*ptr){ temp->link = NULL; node->link = temp; } … } 30 NULL temp W.F. Hu@ant.comm.ccu

  16. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  17. Delete node (1/2) • Delete node : locate the node first. • Assume we have three points • ptr : point to the start of the list • node : points to the node that we wish to delete • trail : points to the predecessor trail node ptr 10 20 30 NULL W.F. Hu@ant.comm.ccu

  18. Delete node (2/2) • There are only two case: • Delete the first node • Delete any other node W.F. Hu@ant.comm.ccu

  19. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  20. Delete First Node (1/2) NULL trail node ptr 10 20 30 NULL Free (node); W.F. Hu@ant.comm.ccu

  21. Delete First Node (2/2) NULL trail node ptr 10 20 30 NULL void delete(list_pointer *ptr, list_pointer trail, list_pointer node) { if (trail) trail->link = node->link; else *ptr = (*ptr)->link; free(node); } W.F. Hu@ant.comm.ccu

  22. Agenda • Insert node • Insert into Empty List • Insert at Beginning • Insert in Middle • Insert at End • Delete node • Delete First Node • General Delete Node W.F. Hu@ant.comm.ccu

  23. General Delete Node (1/4) • Case I : delete node between first node and last node. trail node ptr 10 20 30 NULL W.F. Hu@ant.comm.ccu

  24. General Delete Node (2/3) trail node ptr 10 20 30 NULL void delete(list_pointer *ptr, list_pointer trail, list_pointer node) { if (trail) trail->link = node->link; else *ptr = (*ptr)->link; free(node); } W.F. Hu@ant.comm.ccu

  25. General Delete Node (3/4) • Case II : delete last node trail node ptr 10 20 30 NULL NULL W.F. Hu@ant.comm.ccu

  26. General Delete Node (4/4) trail node ptr 10 20 30 NULL NULL void delete(list_pointer *ptr, list_pointer trail, list_pointer node) { if (trail) trail->link = NULL; else *ptr = (*ptr)->link; free(node); } W.F. Hu@ant.comm.ccu

  27. Q & A W.F. Hu@ant.comm.ccu

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