#include<iostream.h>
#include<conio.h>

struct node
{
int data;
node *right;
node *left;
};

class linklist
{
private:
node *begin;
node *end;
node *temp;
node *leftcur;
node *rightcur;
node *ptr;

public:

linklist()
{
begin    = NULL;
end      = NULL;
leftcur  = NULL;
rightcur = NULL;
temp     = NULL;
ptr      = NULL;
}

void insertnode(int N)
{
temp = new node;
temp -> data = N;
temp -> left = NULL;
temp -> right = NULL;


if(begin==NULL && end==NULL)
{
begin=temp;
end=temp;
}

if(leftcur != NULL)
{
while(leftcur->right!=NULL)
	{
	leftcur = leftcur->right;
	}
	leftcur->right=temp;
	end = temp;
	end->left=leftcur;
	leftcur=leftcur->right;
	leftcur->right=NULL;
}
if(leftcur==NULL)
{leftcur=temp;}
}

void READ(void)      // to see in reverse order..write 'end' inplace of begin
{
ptr=begin;
while(ptr!=NULL)
{
cout<<ptr->data<<endl;
ptr=ptr->right;           // and then write left inplace of right
}
}

};


void main(void)
{
clrscr();
linklist r;

r.insertnode(10);
r.insertnode(20);
r.insertnode(30);
r.insertnode(90);
r.READ();

getch();
}