set a er b updt

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

typedef struct data
{
    int a;

    struct data *next;
    struct data *prev;
} data;

data *head=NULL;
data *tail=NULL;

void ins_at_first(int x)
{
    data *new_node=(data*)malloc(sizeof(data));
    new_node->a=x;
    new_node->next=NULL;
    new_node->prev=NULL;

    if(head==NULL)
    {
        head=new_node;
        return;
    }
    new_node->next=head;
    head->prev=NULL;
    head=new_node;

    return;
}

void del_by_pos(int n)
{

    data *temp=head;
    n=n-2;

        while(n--)
        {
            temp=temp->next;


        }
        data *del=temp->next;
        if(del->next==NULL)
        {

            tail=temp;
            temp->next=NULL;
            free(del);
            return;
        }
        del->next->prev=temp;
        temp->next=del->next;
        free(del);
}

void print()
{
    data *temp=head;

    while(temp!=NULL)
    {
        printf("%d ",temp->a);
        temp=temp->next;
    }
    printf("\n");
}



int main()
{
    ins_at_first(9);
    ins_at_first(5);
    ins_at_first(7);
    ins_at_first(3);
    ins_at_first(2);
    ins_at_first(4);

    print();
    del_by_pos(3);
    print();
    del_by_pos(5);
    print();


}