#include<stdio.h>
#include<stdlib.h>
typedef struct node
{
    char a[15];
    char ch[30];
    struct node *next, *prev;
}node;
node *head=NULL, *tail=NULL;
void display_last_to_first()
{
    node *list=tail;
    if(head==NULL)
        {
        printf("No DATA Available!!\n\n");
        }
    else
    {
        while(list!=NULL)
        {
            printf("Name: %s\n", list->ch);
            printf("Roll: %s\n", list->a);
            list=list->prev;
        }
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void display_first_to_last()
{
    node*list=head;
    if(head==NULL)
    {
        printf("There's no data available!!\n");
        }
    else
    {
        while(list!=NULL)
        {
            printf("Name: %s\n", list->ch);
            printf("Roll: %s\n", list->a);
            list=list->next;
        }
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
    }

void display()
{
    printf("1. Display first to last\n");
    printf("2. Display last to first\n");
    printf("Choose an option:\n");
    int n;
    scanf("%d", &n);
    switch(n)
    {
    case 1:
    {
        display_first_to_last();
        break;
    }
    case 2:
    {
        display_last_to_first();
        break;
    }
    default:
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void search_by_pos()
{
    int n;
    printf("Enter the Position:\n");
    scanf("%d", &n);
    node *list=head;
    if(n==1)
    {
        printf("Name: %s\n", list->ch);
        printf("Roll: %s\n\n", list->a);
    }
    else
    {
        n=n-2;
        while(n!=0 && list->next!=NULL)
        {
            list=list->next;
            n--;
        }
        if(list->next==NULL)
        {
            printf("There's No Information!!\n");
        }
        else
        {
            printf("Name: %s\n", list->next->ch);
            printf("Roll: %s\n", list->next->a);
        }
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int y;
    scanf("%d",&y);
    switch(y)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void search_by_value()
{
    int d;
    printf("Enter the Roll:\n");
    scanf("%d", &d);
    node *list=head;
    if(list->a==d)
    {
        printf("Name: %s\n", list->ch);
        printf("Roll: %s\n\n", list->a);
    }
    else
    {
        while(list->a!=d)
        {
            list=list->next;
            if(list==NULL)
            {
                printf("There's No Information!!\n");
                break;
            }
        }
        printf("Name: %s\n", list->ch);
        printf("Roll: %s\n", list->a);
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void search()
{
    printf("1. Search by Value\n");
    printf("2. Search by Position\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        search_by_value();
        break;
    }
    case 2:
    {
        search_by_pos();
        break;
    }
    case 3:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void delete_by_pos()
{

    int n;
    node *list=head, *temp;
    printf("Enter the Position:\n");
    scanf(" %d", &n);
    if(head==NULL)
    {
        printf("There's No Information!!\n");
    }
    else if(n==1)
    {
        if(list->next==NULL)
        {
            printf("The data has been deleted!!\n");
            free(list);
        }
        else
        {
            head=list->next;
            head->prev=NULL;
            printf("The data has been deleted!!\n");
            free(list);
        }
    }
    else
    {
        n=n-2;
        while(n!=0 && list->next!=NULL)
        {
            list=list->next;
            n--;
            if(list==NULL)
            {
                printf("There's no data found!!\n");
                break;
            }
        }
        if(list->next==NULL)
        {
            printf("You've Chosen the Wrong Position!!\n");
        }
        else if(list->next->next==NULL && n==0)
        {
            temp=tail;
            tail=tail->prev;
            tail->next=NULL;
            printf("The data has been deleted!!\n");
            free(temp);
        }
        else if(list->next->next!=NULL && n==0)
        {
            temp=list->next;
            temp->next->prev=list;
            list->next=temp->next;
            printf("The data has been deleted!!\n");
            free(temp);
        }
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }

    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}


void  delete_the_value()
{
    int n;
    printf("Enter the Roll:\n");
    scanf(" %d", &n);
    node*list=head;
    if(head==NULL)
    {
        printf("There's No Information!!\n");
    }
    else if(list->a==n)
    {
        if(list->next==NULL)
        {
            head=NULL;
            tail=NULL;
            printf("The data has been deleted!!\n");
            free(list);
        }
        else
        {
            list->next->prev=NULL;
            head=list->next;
            printf("The data has been deleted!!\n");
            free(list);
        }
    }
    else
    {
        node*temp;
        while(list->a!=n && list->next!=NULL)
        {
            list=list->next;
            if(list==NULL)
            {
                printf("There's no data found!!\n");
                break;
            }
        }
        if(list->a==n && list->next==NULL)
        {
            list=tail;
            temp=list;
            temp->prev->next=temp->next;
            tail=temp->prev;
            printf("The data has been deleted!!\n");
            free(temp);
        }
        else if(list->a==n && list->next!=NULL)
        {
            temp=list;
            temp->prev->next=temp->next;
            temp->next->prev=temp->prev;
            temp->next=NULL;
            temp->prev=NULL;
            printf("The data has been deleted!!\n");
            free(temp);
        }
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void Delete()
{
    printf("1. Delete by value\n");
    printf("2. Delete by position\n");
    printf("Choose a option:");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        delete_the_value();
        break;
    }
    case 2:
    {
        delete_by_pos();
        break;
    }
    case 3:
    {
        exit(0);
        break;
    }

    default :
    {

        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }

}

void insert_at_pos()
{
    int n;
    node *list=head;
    node *N=(node*)malloc(sizeof(node));
    printf("Enter the Name:\n");
    scanf(" %[^\n]", N->ch);
    printf("Enter the Roll:\n");
    scanf(" %[^\n]", N->a);
    N->next=NULL;
    N->prev=NULL;
    printf("Enter the position:\n");
    scanf(" %d", &n);
    if(n==1)
    {
        if(head==NULL)
        {
            head=N;
            tail=N;
        }
        else
        {
            head->prev=N;
            N->next=head;
            head=N;
        }
    }
    else
    {
        n=n-2;
        while(n!=0 && list->next!=NULL)
        {
            list=list->next;
            n--;
        }
        if(list->next==NULL)
        {
            N->prev=tail;
            tail->next=N;
            tail=N;
        }
        else
        {
            list->next->prev=N;
            N->next=list->next;
            N->prev=list;
            list->next=N;
        }
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}
void insert_end()
{
    node *N=(node*)malloc(sizeof(node));
    printf("Enter the Name:\n");
    scanf(" %[^\n]", N->ch);
    printf("Enter the Roll:\n");
    scanf(" %[^\n]", N->a);
    N->next=NULL;
    N->prev=NULL;
    node *list=head;
    if(head==NULL && tail==NULL)
    {
        head=N;
        tail=N;
    }
    else
    {
        tail->next=N;
        N->prev=tail;
        tail=N;
    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}

void insert_first()
{
    node *N=(node*)malloc(sizeof(node));
    printf("Enter the Name:\n");
    scanf(" %[^\n]", N->ch);
    printf("Enter the Roll:\n");
   scanf(" %[^\n]", N->a);
    N->next=NULL;
    N->prev=NULL;
    if(head==NULL && tail==NULL)
    {
        head=N;
        tail=N;
    }
    else
    {
        head->prev=N;
        N->next=head;
        head=N;

    }
    printf("1. Menu\n");
    printf("2. Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        menu();
        break;
    }
    case 2:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}
void add()
{
    printf("1.Add at frist\n");
    printf("2.Add at end\n");
    printf("3.Add by position\n");
    printf("4.Exit\n");
    printf("Choose an option:\n");
    int x;
    scanf("%d", &x);
    switch(x)
    {
    case 1:
    {
        insert_first();
        break;
    }
    case 2:
    {
        insert_end();
        break;
    }
    case 3:
    {
        insert_at_pos();
        break;
    }
    case 4:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}
void menu()
{
    printf("1.Add\n");
    printf("2.Delete\n");
    printf("3.Search\n");
    printf("4.Display\n");
    printf("5.Exit\n");
    printf("Choose an option:\n");
    int y;
    scanf("%d", &y);
    switch(y)
    {
    case 1:
    {
        add();
        break;
    }
    case 2:
    {
        Delete();
        break;
    }
    case 3:
    {
        search();
        break;
    }
    case 4:
    {
        display();
        break;
    }
    case 5:
    {
        exit(0);
        break;
    }
    default :
    {
        printf("You've chosen a wrong option!! Choose the correct one:\n");
        menu();
        break;
    }
    }
}
int main()
{
    printf("..........!!Doubly Link list!!........\n");
    menu();
    return 0;
}