Insertion in Linked list

 

#include <stdio.h>

#include<stdlib.h>

struct node{

    int data;

    struct node *link;

};

struct node * Insert_beg(struct node *head, int s){

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

   

    e->data = s;

    e->link = head;

    return e;

}

struct node * Insert_end(struct node *head, int s){

    struct node *ptr;

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

   

    e->data = s;

   

    ptr = head;

    while(ptr->link!=NULL){

        ptr = ptr->link;

    }

    ptr->link = e;

    e->link = NULL;

    return head;

}

struct node * Insert_pos(struct node *head, int s, int pos){

    struct node *i;   // i is a position of curser

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

    i = head;

    int j = 0;

    while(j!=pos-1){

        i = i->link;

        j++;

    }

    e->data = s;

    e->link = i->link;

    i->link = e;

    return head;

}

void display(struct node *ptr){

    while(ptr!=NULL){

        printf(" %d ",ptr->data);

        ptr = ptr->link;

    }

}

int main()

{

    struct node *head;

    struct node *a;

    struct node *b;

    head = malloc(sizeof(struct node));

    a = malloc(sizeof(struct node));

    b = malloc(sizeof(struct node));

    head->data = 2;

    head->link= a;

    a->data = 3;

    a->link = b;

    b->data = 4;

    b->link = NULL;

    int m;

printf("Enter the Element to add at the begninning: ");

scanf("%d",&m);

head = Insert_beg(head,m);

printf("Enter the Element to add at the end: ");

    scanf("%d",&m);

head = Insert_end(head,m);

printf("Enter which position you want to add: ");

int p;

scanf("%d",&p);

printf("Enter the Element to add at the end: ");

scanf("%d",&m);

head = Insert_pos(head,m,p);

display(head);

    return 0;

}