Insertion of Linkedlist (all cases) 🫨🎊👍👍

  By : Himanshu Tiwari

Code

#include<stdio.h>

#include<stdlib.h>

struct node

{

    int data;

    struct node *next;

};

void printLinkedlist(struct node *p) {

  while (p != NULL) {

    printf("%d ", p->data);

    p = p->next;

  }

}

struct node *insertatfirst(struct node *head,int data){

    struct node *ptr=(struct node *)malloc(sizeof(struct node));

    ptr->next=head;

    ptr->data=data;

    return ptr;

}

struct node *insertatindex(struct node *head,int data,int index){

    struct node *ptr=(struct node *)malloc(sizeof(struct node));

    struct node*p=head;

    int i=0;

    while (i!=index-1){

        p=p->next;

        i++;

    }

    ptr->data=data;

    ptr->next=p->next;

    p->next=ptr;

    return head;

}

struct node *insertatend(struct node *head,int data){

    struct node *ptr=(struct node *)malloc(sizeof(struct node));

    ptr->data=data;

    struct node*p=head;

    while (p->next!=NULL)

    {

        p=p->next;

    }

    p->next=ptr;

    ptr->next=NULL;

    return head;

}

struct node *insertafternode(struct node *head,struct node *prevnode,int data){

    struct node *ptr=(struct node *)malloc(sizeof(struct node));

    ptr->data=data;

    ptr->next=prevnode->next;

    prevnode->next=ptr;

    return head;

}

int main(){

    struct node *head;

    struct node *two;

    struct node *three;

    //memory allocation

    head=malloc(sizeof(struct node));

    two=malloc(sizeof(struct node));

    three=malloc(sizeof(struct node));

    head->data=10;

    head->next=two;

    two->data=20;

    two->next=three;

    three->data=30;

    three->next=NULL;

    printLinkedlist(head);

    printf("\n");

    // head=insertatindex(head,50,2);

    // head=insertatend(head,100);

    head=insertafternode(head,head,44);

    printLinkedlist(head);

    return 0;

}