![}
}
printf(" ]");
}](https://image.slidesharecdn.com/a3289285751965622018singlylinklist-180304131729/85/Linked-List-14-320.jpg)
Linked List
- 1. Singly Link List: Singly Link List contain a data find and also a tail to point next data field or node. Singly Link List Doubly Link List: Doubly Link List contain a head, a data find and also a tail to point next data field or node. Doubly Link List Circular Link List: In Circular Link List, the last tail point to the first nodes head. If we do like this, it's called circular linked list otherwise it's called linear or open list. Link List Operations 1. Pseudo-code for Insert at Beginning Pseudo-code for Insert at Beginning
- 2. getcell(m) //here m is a new cell containing data 1 m -> data = 1 m -> link = head head = m 2. Pseudo-code for insert at End Pseudo-code for insert at End while(head->link != NULL) head = head-> link m-> link = NULL m->data = 8 head->link = m 3. Pseudo-code for delete from Beginning Pseudo-code for delete from Beginning temp = head head = head->link
- 3. free(temp) 4. Pseudo-code for delete from End Before deletion process: Pseudo-code for delete from End(before) temp = head while(head->link != NULL) { temp = head head = head->link } Pseudo-code for delete from End(before) temp->link = NULL free(head) After Deletion process: Pseudo-code for delete from End(after deletion)
- 4. 5. Pseudo-code for insert at Kth position of the list insert at Kth position of the list getcell(m) //we will insert in pos=3 insert at Kth position of the list pos = k for(i=1; i<=pos-2; i++) head = head->link temp = head->link head->link = m
- 5. m>link = temp 6. Pseudo-code for delete from Kth position of the list Before deletion process: delete from Kth position of the list(before) for(i=1; i<=pos-2; i++) head = head->link temp = head->link delete from Kth position of the list(before) head->link = temp->link free(temp) After Deletion process: delete from Kth position of the list(after deletion)
- 6. 7. Pseudo-code for search data in list Pseudo-code for search data in list let key = 7 found = false while(head->link !=Null && found == false) { if(head->data == key) found = true else head = head->link } if(found == true) //search key found else Not found Doubly/ Two-Way Linked List Doubly Linked List is a variation of Linked list in which navigation is possible in both ways, either forward and backward easily as compared to Single Linked List. Following are the important terms to understand the concept of doubly linked list. • Link − Each link of a linked list can store a data called an element. • Next − Each link of a linked list contains a link to the next link called Next. • Prev − Each link of a linked list contains a link to the previous link called Prev.
- 7. • LinkedList − A Linked List contains the connection link to the first link called First and to the last link called Last. Doubly Linked List Representation As per the above illustration, following are the important points to be considered. • Doubly Linked List contains a link element called first and last. • Each link carries a data field(s) and two link fields called next and prev. • Each link is linked with its next link using its next link. • Each link is linked with its previous link using its previous link. • The last link carries a link as null to mark the end of the list. Basic Operations Following are the basic operations supported by a list. • Insertion − Adds an element at the beginning of the list. • Deletion − Deletes an element at the beginning of the list. • Insert Last − Adds an element at the end of the list. • Delete Last − Deletes an element from the end of the list. • Insert After − Adds an element after an item of the list. • Delete − Deletes an element from the list using the key. • Display forward − Displays the complete list in a forward manner. • Display backward − Displays the complete list in a backward manner.
- 8. Insertion Operation Following code demonstrates the insertion operation at the beginning of a doubly linked list. Example //insert link at the first location void insertFirst(int key, int data) { //create a link struct node *link = (struct node*) malloc(sizeof(struct node)); link->key = key; link->data = data; if(isEmpty()) { //make it the last link last = link; } else { //update first prev link head->prev = link; } //point it to old first link link->next = head; //point first to new first link head = link; }
- 9. Deletion Operation Following code demonstrates the deletion operation at the beginning of a doubly linked list. Example //delete first item struct node* deleteFirst() { //save reference to first link struct node *tempLink = head; //if only one link if(head->next == NULL) { last = NULL; } else { head->next->prev = NULL; } head = head->next; //return the deleted link return tempLink; } Insertion at the End of an Operation Following code demonstrates the insertion operation at the last position of a doubly linked list. Example
- 10. //insert link at the last location void insertLast(int key, int data) { //create a link struct node *link = (struct node*) malloc(sizeof(struct node)); link->key = key; link->data = data; if(isEmpty()) { //make it the last link last = link; } else { //make link a new last link last->next = link; //mark old last node as prev of new link link->prev = last; } //point last to new last node last = link; } Circular Linked List Circular Linked List is a variation of Linked list in which the first element points to the last element and the last element points to the first element.
- 11. Both Singly Linked List and Doubly Linked List can be made into a circular linked list. Singly Linked List as Circular In singly linked list, the next pointer of the last node points to the first node. Doubly Linked List as Circular In doubly linked list, the next pointer of the last node points to the first node and the previous pointer of the first node points to the last node making the circular in both directions. As per the above illustration, following are the important points to be considered. • The last link's next points to the first link of the list in both cases of singly as well as doubly linked list. • The first link's previous points to the last of the list in case of doubly linked list. Basic Operations Following are the important operations supported by a circular list. • insert − Inserts an element at the start of the list. • delete − Deletes an element from the start of the list. • display − Displays the list.
- 12. Insertion Operation Following code demonstrates the insertion operation in a circular linked list based on single linked list. Example //insert link at the first location void insertFirst(int key, int data) { //create a link struct node *link = (struct node*) malloc(sizeof(struct node)); link->key = key; link->data= data; if (isEmpty()) { head = link; head->next = head; } else { //point it to old first node link->next = head; //point first to new first node head = link; } } Deletion Operation Following code demonstrates the deletion operation in a circular linked list based on single linked list. //delete first item struct node * deleteFirst() {
- 13. //save reference to first link struct node *tempLink = head; if(head->next == head) { head = NULL; return tempLink; } //mark next to first link as first head = head->next; //return the deleted link return tempLink; } Display List Operation Following code demonstrates the display list operation in a circular linked list. //display the list void printList() { struct node *ptr = head; printf("n[ "); //start from the beginning if(head != NULL) { while(ptr->next != ptr) { printf("(%d,%d) ",ptr->key,ptr->data); ptr = ptr->next;