C Program For Linked List Insertion

 

C  PROGRAM FOR LINKED LIST INSERTION

1. Insertion at beginning

2. Insertion at End

3. Insertion at an Index

4. Insertion after a given node 

CODE

#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: Insertion At Beginning 

struct Node * insertAtFirst(struct Node *head, int data)

{

struct Node *ptr;

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

ptr->data=data;

ptr->next=head;

return ptr;

}

//case 2: Insertion At End

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;

}

// case 3: Insertion at Index

struct Node * insertAtIndex(struct Node *head, int index,int data)

{

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

ptr->data=data;

struct Node *p=head;

int i=0;

while(i!=index-1)

{

p=p->next;

i++;

}

ptr->next=p->next;

p->next=ptr;

return head;

}

//case 4: Insertion after a given node

struct Node * insertAfterNode(struct Node *head, struct Node *node, int data)

{

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

ptr->data=data;

ptr->next=node->next;

node->next=ptr;

return head;

}

int main()

{

struct Node *head;

struct Node *third;

struct Node *second;

head=(struct Node *)malloc(sizeof(struct Node));

second=(struct Node *)malloc(sizeof(struct Node));

third=(struct Node *)malloc(sizeof(struct Node));

head->data=1;

head->next=second;

second->data=2;

second->next=third;

third->data=3;

third->next=NULL;

printf("Linked List Before Insertion\n");

LinkedListTraversal(head);

//head=insertAtFirst(head,3433);

//head=insertAtEnd(head,3433);

//head=insertAtIndex(head,2,455);

head=insertAfterNode(head,second,567);

printf("After Insertion\n");

LinkedListTraversal(head);

return 0;

}