#include<stdio.h>

#include<malloc.h>

#include<conio.h>

struct node

};

struct node* create(struct node *head)

{

struct node *p,*c;

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

int n,i=0;

printf("\nEnter number of elements to be added : ");

scanf("%d",&n);

do

{

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

printf("\nEnter the data : ");

scanf("%d",&c->data);

c->next=NULL;

c->prev=NULL;

if(head==NULL)

{

head=c;

c->prev=head;

}

else

{

p->next=c;

c->prev=p;

}

p=c;

i++;

}while(i<n);

return head;

}

void display(struct node *head)

{

struct node *p;

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

p=head;

if(p!=NULL)

{

while(p!=NULL)

{

printf("%d\t",p->data);

p=p->next;

}

printf("\n");

p=head;

while(p->next!=NULL)

p=p->next;

while(p!=head)

{

printf("%d\t",p->data);

p=p->prev;

}

printf("%d\t",p->data);

}

}

struct node* make_empty(struct node *head)

{

while(head->next!=NULL)

{

head=head->next;

free(head->prev);

}

free(head);

printf("\nList is empty");

return NULL;

}

struct node* del(struct node *head,int pos)

{

int i=0;

struct node *c,*p;

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

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

c=head;

while(c!=NULL)

{

i++;

if(i==pos)

{

if(pos==1)

{

head=c->next;

c->next->prev=head;

p=c;

free(p);

return head;

}

else

{

c->prev->next=c->next;

if(c->next!=NULL)

c->next->prev=c->prev;

p=c;

free(p);

return head;

}

}

c=c->next;

}

}

struct node* insert(struct node* head,int pos)

{

int i=0;

struct node *p,*c,*temp;

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

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

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

printf("\nEnter the data to be inserted : ");

scanf("%d",&temp->data);

temp->next=NULL;

temp->prev=NULL;

c=head;

while(c!=NULL)

{

i++;

if(i==pos)

{

if(pos==1)

{

head=temp;

temp->next=c;

temp->prev=head;

c->prev=temp;

}

else

{

temp->prev=c->prev;

c->prev->next=temp;

temp->next=c;

c->prev=temp;

}

}

p=c;

c=c->next;

}

if(pos==0)

{

p->next=temp;

temp->prev=p;

}

return head;

}

int locate(struct node* head, int data)

{

struct node *p;

int i=0,flag=0;

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

p=head;

while(p!=NULL)

{

i++;

if(p->data==data) flag=i;

p=p->next;

}

return flag;

}

int count(struct node* head)

{

struct node *p;

int i=0;

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

p=head;

while(p!=NULL)

{

i++;

p=p->next;

}

return i;

}

struct node* retrieve(struct node* head, int pos)

{

struct node *p,*flag;

int i=0;

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

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

flag->data=-1;

flag->next=NULL;

p=head;

while(p!=NULL)

{

i++;

if(i==pos) flag=p;

p=p->next;

}

return flag;

}

int main()

{

struct node *head;

int pos,choice,data;

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

head=NULL;

do

{

printf("\n1.Create\n2.Insert\n3.Delete\n4.Locate\n5.Retrieve\n6.Display\n7.Make empty\n8.Exit");

printf("\n Enter choice : ");

scanf("%d",&choice);

switch(choice)

{

case 1: head=create(head);break;

case 2:

{

printf("\n1.Beginning\n2.End\n3.Middle\nEnter choice :");

scanf("%d",&choice);

switch(choice)

{

case 1: head=insert(head,1);break;

case 2: head=insert(head,0);break;

case 3: printf("\nEnter the position to be inserted : ");

scanf("%d",&pos);

head=insert(head,pos);

break;

}

}break;

case 3:

{

printf("\nEnter the position to be deleted : ");

scanf("%d",&pos);

head=del(head,pos);

}break;

case 4:

{

printf("\nEnter the data to be located : ");

scanf("%d",&data);

pos=locate(head,data);

if(pos==0)printf("\nData not found\n");

else printf("\nData found at position %d\n",pos);

}break;

case 5:

{

struct node *temp;

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

printf("\nEnter the position to be retrieved : ");

scanf("%d",&pos);

temp=retrieve(head,pos);

if(temp->data==-1)printf("\nData not found\n");

else printf("\nData found at position %d is %d\n",pos,temp->data);

}break;

case 6: display(head);break;

case 7: head=make_empty(head);break;

case 8: return 0;

}

}while(5);

getch();

}