Algorithm
INPUT: HEADER IS POINTER TO THE HEADER NODE OF THE LINKEDLIST AND POSITION
OUTPUT: LINKEDLIST WITHOUT THE DELETED ELEMENT
DATA STRUCTURE: DOUBLY LINKEDLIST
STEP 1: START
STEP 2: PTR=HEADER->LINK
STEP 3: FOR( I=1 TO POS) DO
STEP 4: PTR1=PTR
STEP 5: PTR=PTR->RLINK
STEP 6: ENDWHILE
STEP 7: PTR2=PTR->RLINK
STEP 8: PTR1->RLINK=PTR
STEP 9: PTR2->LLINK=PTR1
STEP 10: FREE(PTR)
STEP 11: ENDWHILE
Code
#include <stdio.h>
#include <stdlib.h>
int getnode(int);
void display();
void displayrev();
void deleteatany();
int x, pos, n, item;
struct node
{
int data;
struct node *llink;
struct node *rlink;
};
struct node *prev, *head, *tail, *news, *p, *ptr, *ptr1, *ptr2;
struct node *q1;
struct node *header, *header1;
struct node *q, *r, *s;
int main()
{
int a;
char ch;
printf("ENTER THE LIMIT ");
scanf("%d", &n);
getnode(n);
printf("ENTER THE POSITION WHERE YOU WANT TO DELETE");
scanf("%d",&pos);
deleteatany();
printf("\n");
display(header);
return 0;
}
void deleteatany()
{
ptr = header->rlink;
struct node *ptr1;
ptr1 = malloc(sizeof(struct node));
for (int i = 1; i < pos; i++)
{
ptr1 = ptr;
ptr = ptr->rlink;
}
ptr2 = ptr->rlink;
ptr1->rlink = ptr2;
ptr2->llink = ptr1;
free(ptr);
}
void display(struct node *head1)
{
struct node *ptr;
ptr = head1->rlink;
while (ptr != NULL)
{
printf("%d ", ptr->data);
ptr = ptr->rlink;
}
}
void displayrev()
{
struct node *ptr;
ptr = tail;
printf("reverse traversal ");
while (ptr != NULL)
{
printf("%d ", ptr->data);
ptr = ptr->llink;
}
}
int getnode(int n)
{
header = malloc(sizeof(struct node));
head = NULL;
ptr = malloc(sizeof(struct node));
for (int i = 0; i < n; i++)
{
ptr->llink = NULL;
p = malloc(sizeof(struct node));
scanf("%d", &p->data);
ptr->rlink = p;
p->llink = ptr;
p->rlink = NULL;
if (head == NULL)
{
head = p;
p->llink = NULL;
ptr->llink = head;
}
else
{
prev->rlink = p;
p->llink = prev;
}
prev = p;
}
tail = prev;
header->rlink = head;
header->llink = NULL;
display(header);
displayrev();
return 0;
}
Output
user@computer$ : ENTER THE LIMIT 5
1
2
3
4
5
1 2 3 4 5 reverse traversal 5 4 3 2 1 ENTER THE POSITION WHERE YOU WANT TO DELETE3
1 2 4 5