#include <iostream.h>

class node
{
public:
int value;           //value stored in the node 
node *next;          //pointer to next node 
node *prev;          //pointer to previous node 
};

class dlist
{
public:
node *front;       //pointer to front of list   
node *back;        //pointer to back of list  

dlist()
{
	front=NULL;
	back=NULL;
}

void insertFront(int value);             
void insertBack(int value);
void removeFront();
void removeBack();
void insertBefore(int value,node *nodeB);
void insertAfter(int value,node *nodeA);
void removeBefore(node *nodeB);
void removeAfter(node *nodeA);
void removeNode(node *newNode);
void printDListFront();
void printDListBack();
};

//insert a node before nodeB
	void dlist::insertBefore(int value,node *nodeB)    
	{
		node *newNode;
		newNode=new node();
		newNode->prev=nodeB->prev;
		newNode->next =nodeB;
		newNode->value =value;	
		if(nodeB->prev==NULL)
		{
		this->front=newNode;	
		}
	nodeB->prev=newNode;
	removeNode(newNode);
	
	}

//insert a node before the front node 
void dlist::insertFront (int value)
		{
			node *newNode;
			if(this->front==NULL)
			{
				newNode=new node();
				this->front=newNode;
				this->back =newNode;
				 newNode->prev=NULL;
				 newNode->next=NULL;
				 newNode->value=value;
				 
			}
			else
			{
				 insertBefore(value,this->front );
			}
		}

//insert a node after  nodeB
void dlist::insertAfter(int value,node *nodeB)
	{
		node *newNode;
		newNode=new node();
		newNode->next= nodeB->next ;
		newNode->prev  =nodeB;
		newNode->value =value;

		if(nodeB->next==NULL)
		{
			cout<<"\n "<< endl;
			this->back =newNode;	
		}
			nodeB->next=newNode;
			cout<<"2"<<endl;
	}
//insert a node after the last node 
	void dlist::insertBack (int value)
	{          
			if(this->back==NULL)
			{
				cout<<"insert at back";
				insertFront(value);
			}
			else
			{
				cout<<"insert at back";
				 insertAfter(value,this->back  );
			}
	}

//remove the front node 
void dlist::removeFront ()
{
	removeNode(this->front);
}

//remove a back node 
void dlist::removeBack  ()
{
	removeNode(this->back);
	
}

//remove before a node 
void dlist::removeBefore(node *nodeB)
{

	if(nodeB->prev==this->front)
	{
		this->front=nodeB;
		this->front->prev=NULL;
	}
	else
	{
     removeNode(nodeB->prev);
	}
}

//remove after a node 
void dlist::removeAfter(node *nodeA)
{
	if(nodeA->next==this->back)
	{
		this->back=nodeA;
		this->back->next=NULL;
	}
	else
	{
	removeNode(nodeA->next);
	}
}

//remove a perticular node 
void dlist::removeNode(node *nodeToRemove)
{
	if(nodeToRemove==this->front)
	{
		this->front=this->front->next;
		this->front->prev=NULL;
	}
	else if (nodeToRemove==this->back)
	{
		this->back=this->back->prev;
		this->back->next=NULL	;
	}
	else
	{
	nodeToRemove->prev->next=nodeToRemove->next;
	nodeToRemove->next->prev=nodeToRemove->prev;
	}
}

//Print the list from front 
void dlist::printDListFront()
{
	node* curr2;
		curr2= this->front;
		cout<<"\n-----\n";
		cout<<"Queue\n";
		cout<<"-----\n";
		//cout<<"size:"<<getQueueSize()<<endl;
	while(curr2!=NULL)
		{
			cout<<" |"<<curr2->value<<"|";
			curr2=curr2->next;
		}
		cout<<endl;
}// print the Double Linked List from front


// print the Double Linked List from backwards
void dlist::printDListBack()
{
	node* curr2;
		curr2= this->back;
		cout<<"\n-----\n";
		cout<<"Queue\n";
		cout<<"-----\n";
		//cout<<"size:"<<getQueueSize()<<endl;
	while(curr2!=NULL)
		{
			cout<<" |"<<curr2->value<<"|";
			curr2=curr2->prev;
		}
		cout<<endl;
}// print the Double Linked List from back

void main()
{
	dlist *st ;
	st= new dlist();
st->insertBack(8); 
st->printDListFront ();
st->insertBack(5); 
st->printDListFront ();
st->insertBack(6); 
st->printDListFront ();
st->insertFront(1) ;
st->printDListFront ();
st->insertFront(3) ;
st->printDListFront ();
st->insertBack(7); 
st->printDListFront ();
st->removeFront();
st->printDListFront ();
st->removeBack();
st->printDListFront ();
}