Insert Node (At beg,Nth,End) Doubly Linked List

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

struct node
{
    int data;
    struct node *prev,*next;
}*head,*p;

int main()
{
    int n,m,o,position,ndata;
    printf("Enter Total Number Of Node: ");
    scanf("%d",&n);
    createList(n);

    printf("\nDoubly Linked List is: ");
    displayList();

    printf("\nEnter data to insert at the beginning: ");
    scanf("%d",&m);

    insertatbeg(m);

    displayList();

    printf("\nEnter data to insert at the end: ");
    scanf("%d",&o);

    insertatend(o);

    displayList();

    printf("\nEnter any middle position to add node: ");
    scanf("%d",&position);

    printf("\nEnter the data for node %d: ",position);
    scanf("%d",&ndata);

    insertATn(ndata,position);

    displayList();

    return 0;

}
void createList(int n)
{
    int i,data;
    struct node *temp;

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

    printf("Enter data for node 1: ");
    scanf("%d",&data);

    temp->data=data;
    temp->prev=NULL;
    temp->next=NULL;

    head=temp;
    p=temp;

    for(i=2;i<=n;i++)
    {
        temp=(struct node *)malloc(sizeof(struct node));
        printf("Enter data for node %d: ",i);
        scanf("%d",&data);

        temp->data=data;
        temp->next=NULL;
        temp->prev=p;
        p->next=temp;

        p=p->next;

    }
}
void displayList()
{
    struct node *temp;

    temp=head;

    while(temp != NULL)
    {
        printf("\n%d",temp->data);
        temp=temp->next;
    }
}
void insertatbeg(int data)
{
    struct node *temp;

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

    temp->data=data;
    temp->next=head;
    temp->prev=NULL;

    head->prev=temp;

    head=temp;
}
void insertatend(int data)
{
    struct node *temp;

    temp=(struct node *)malloc(sizeof(struct node));
    temp->data=data;
    temp->next=NULL;
    temp->prev=p;

    p->next=temp;
    p=temp;
}
void insertATn(int data,int position)
{
    struct node *temp,*q;
    int i=1;
    q=head;


    temp=(struct node *)malloc(sizeof(struct node));
    temp->data=data;

    while(i<position-1 && q != NULL)
    {
        q=q->next;
        i++;
    }


    temp->prev=q;
    temp->next=q->next;

    if(q->next != NULL)
    {
        q->next->prev=temp;
        q->next=temp;
    }
}