//bismilllah hir rahmanir rahim

#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 insert_at_first(int x)
{
    data *laboni=(data*)malloc(sizeof(data));
    laboni->a=x;
    laboni->next=NULL;
    laboni->prev=NULL;
    if(head==NULL)
    {
        head=laboni;
        return;
    }
    head->prev=laboni;
    head->next=laboni;
    head=laboni;
}
void insert_at_end(int x)
{
    data *laboni=(data*)malloc(sizeof(data));


    laboni->prev=NULL;
    laboni->a=x;
    laboni->next=NULL;
    if(head==NULL)
    {
        head=laboni;
        return;
    }
    data *temp=head;
    while(temp->next!=NULL)
    {
        temp=temp->next;


    }
    temp->next=laboni;
    laboni->prev=temp;
}
void InsertAtN(int x,int d)
{
    int i;
    data *laboni=(data*)malloc(sizeof(data));
    data*tempe;
    data*tempf;

    laboni->a=x;

    laboni->a=d;
    if(x==1 || head==NULL)
    {
        if(head==NULL && x==1)
        {
            laboni->prev=laboni->next=NULL;
            head=laboni;
            return;
        }
        head->prev=laboni;
        laboni->prev=NULL;
        laboni->next=head;
        head=laboni;
        return;
    }
    tempe=head;
    for(i=0; i<x-2; i++)
    {
        tempe=tempe->next;

    }
    laboni->next=tempe->next;
    laboni->prev=tempe;
    tempe->next=laboni;
    tempf=laboni->next;
    tempf->prev=laboni;
}





void deletenode(int n)

{

    data *temp=head;
    data *del=temp->next;
    if(head==NULL)
    {
        return;
    }
    if(n==1)
    {
        head=head->next;
        head->prev=NULL;
        free(temp);

    }
    if(del->next==NULL)
    {
        tail=temp;
        free(del);
        return;
    }
    n=n-2;
    while(n!=0 && temp->next!=NULL)
    {
        temp=temp->next;
        n--;
    }
    del=temp->next;
    temp->next=del->next;
    del->next->prev=temp;
    free(del);

}
void deletevalue(int x)
{
    data *del=NULL;
    data *temp=head;
    if(head==NULL)
    {
        return;
    }
    if(head->a==x)
    {
        head=head->next;
        head->prev=NULL;
        free(temp);
        return;
    }

    while(temp->next->a!=x)
    {
        temp=temp->next;
        if(temp->next==NULL)
        {
            return;
        }
    }
    del=temp->next;
    temp->next=del->next;
    del->next->prev=temp;
    free(del);
}

int sum()
{
    int s=0;
    data *temp=head;
    while(temp!=NULL)
    {
        s=s+temp->a;
        temp=temp->next;
    }
    return s;

}
double avg()
{
    int count=0;
    double s=0;
    data *temp=head;
    while(temp!=NULL)
    {
        s=s+temp->a;

        count++;
        temp=temp->next;
    }

    if(count==0)
    {
        return 0;
    }
    return s/count;

}


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








int main()
{
       printf("asssalamualaikum sir,,,\n");
    printf("entry the first--");
    insert_at_first(3);
    insert_at_first(4);
    insert_at_first(6);
    print();
    printf("entry the end--");
    insert_at_end(7);
    insert_at_end(8);
    insert_at_end(9);
    print();
    printf("the nth position--");
    InsertAtN(3,3);

    print();
     printf("the delete position--");
    deletenode(3);

    print();

    printf("the sum is %d \n",sum());
    printf("the avarage is %.2lf\n",avg());
     printf("the delete value position--");
    deletevalue(8);
    print();



printf("thank you sir ,,,,,,,,,alllah hafej");

}