dellinklist.c

#include <stdio.h>
#include <stdlib.h>

struct Node
{
    int data;
    struct Node *next;
};
void linkedListTraversal(struct Node *ptr)
{
    while (ptr != NULL)
    {
        printf("Element: %d\n", ptr->data);
        ptr = ptr->next;
    }
}
// Case 1: Deleting the first element from the linked list
struct Node *deleteFirst(struct Node *head)
{
    struct Node *ptr = head;
    head = head->next;
    free(ptr);
    return head;
}
// Case 2: Deleting the element at a given index from the linked list
struct Node *deleteAtIndexx(struct Node *head, int index)
{
    struct Node *p = head;
    struct Node *q = head->next;
    for (int i = 0; i < index - 1; i++)
    {
        p = p->next;
        q = q->next;
    }

    p->next = q->next;
    free(q);
    return head;
}
// Case 3: Deleting the last element
struct Node *deleteAtLast(struct Node *head)
{
    struct Node *p = head;
    struct Node *q = head->next;
    while (q->next != NULL)
    {
        p = p->next;
        q = q->next;
    }

    p->next = NULL;
    free(q);
    return head;
}
// Case 4: Deleting the element with a given value from the linked list
struct Node *deleteAtIndex(struct Node *head, int value)
{
    struct Node *p = head;
    struct Node *q = head->next;
    while (q->data != value && q->next != NULL)
    {
        p = p->next;
        q = q->next;
    }

    if (q->data == value)
    {
        p->next = q->next;
        free(q);
    }
    return head;
}
int inpu(int n){
    printf("Enter A numbver : ");
    scanf("%d",&n);
    return n;
}
int main()
{
    struct Node *head;
    struct Node *second;
    struct Node *third;
    struct Node *fourth;
    // Allocate memory for nodes in the linked list in Heap
    head = (struct Node *)malloc(sizeof(struct Node));
    second = (struct Node *)malloc(sizeof(struct Node));
    third = (struct Node *)malloc(sizeof(struct Node));
    fourth = (struct Node *)malloc(sizeof(struct Node));

    // Link first and second nodes
    head->data = 20;
    head->next = second;

    // Link second and third nodes
    second->data = 11;
    second->next = third;

    // Link third and fourth nodes
    third->data = 8;
    third->next = fourth;

    // Terminate the list at the third node
    fourth->data = 4;
    fourth->next = NULL;
    
    
    printf("Linked list before deletion\n");
    linkedListTraversal(head);
    int input;
    printf("Enter Your Choice : \n");
    printf("1)1st Element, 2)Given Index, 3)Last Element, 4)Given Value :");
        scanf("%d", &input);
    if (input == 1)
    {
        head = deleteFirst(head);
        printf("Linked list after deletion\n");
        linkedListTraversal(head);
    }
    else if (input == 2)
    {
        int n;
        printf("Enter A Number : ");
        scanf("%d",&n);
        head = deleteAtIndexx(head, n);
        printf("Linked list after deletion\n");
        linkedListTraversal(head);
    }
    else if (input == 3)
    {
        head = deleteAtLast(head);
        printf("Linked list after deletion\n");
        linkedListTraversal(head);
    }
    else{
        int p;
        printf("Enter A Value : ");
        scanf("%d",&p);
        head = deleteAtIndex(head, p);
        printf("Linked list after deletion\n");
        linkedListTraversal(head);
    }
    return 0;
}