Question

Deletion at beginning in Doubly Linked List

Answer 1

Deletion at beginning in Doubly Linked List

Algorithm

WRITE UNDERFLOW GOTO STEP 6 STEP 1: IF HEAD = NULL STEP 2: SET PTR = HEAD STEP 3: SET HEAD = HEAD → NEXT STEP 4: SET HEAD → PREV = NULL STEP 5: FREE PTR STEP 6: EXIT

Program Code

#include<stdio.h> #include<stdlib.h> #include<conio.h> void create(int); void beginning_delete(); struct node { int data; struct node *next; struct node *prev; }; struct node *head; void main () {         clrscr(); int choice,item; do  { printf("1.Append List\n2.Delete node from beginning\n3.Exit\nEnter your choice: "); scanf("%d",&choice); switch(choice) { case 1: printf("Enter the item: "); scanf("%d",&item); create(item); break; case 2: beginning_delete(); break; case 3: exit(0); break; default: printf("\nPlease enter valid choice!\n"); } }while(choice != 3); } void create(int item) {    struct node *ptr = (struct node *)malloc(sizeof(struct node));    if(ptr == NULL)    {        printf("OVERFLOW\n\\n");    }    else    {    if(head==NULL)    {        ptr->next = NULL;        ptr->prev=NULL;        ptr->data=item;        head=ptr;    }    else    {        ptr->data=item;        ptr->prev=NULL;        ptr->next = head;        head->prev=ptr;        head=ptr;    } printf("Node Inserted!\n\n"); } } void beginning_delete() { struct node *ptr;     if(head == NULL) { printf("UNDERFLOW\n\n"); } else if(head->next == NULL) { head = NULL; free(head); printf("Node Deleted!\n\n"); } else { ptr = head; head = head -> next; head -> prev = NULL; free(ptr); printf("Node Deleted!\n\n"); } }

Output

---

For more Data Structures & Algorithms Tutorials Click here

---