C plus plus program to implement circular queue using doubly linked list?

#include<iOStream.h>

class node

{

public:

int data;

node* link;

};

class queue

{

node* front;

node* back;

public:

queue()

{

front=NULL;

back=NULL;

}

void enqueue(int d)

{

node* ptr;

ptr=new node;

ptr->data=d;

ptr->link=NULL;

if(front==NULL)

{

front=ptr;

back=ptr;

}

else

{

back->link=ptr;

back=back->link;

}

}

void dequeue()

{

node* ptr;

ptr=front;

if(front==NULL)

cout<<"\n Nothing can be deleted. \n";

else

{

ptr=front;

front=front->link;

delete ptr;

ptr=NULL;

cout<<"\n The first element has been deleted.\n";

Front();

}

}

void If_Empty()

{

if(front==NULL)

cout<<"\n The queue is empty.\n ";

}

void Front()

{

if(front!=NULL)

cout<<"\n The first element is "<<front->data<<endl;

}

};

void main()

{

queue q;

int data;

char opt;

do

{

cout<<" Enter your data:\t";

cin>>data;

q.enqueue(data);

cout<<"\n Do you want to continue:\t";

cin>>opt;

}while(opt=='y'opt=='Y');

q.Front();

q.dequeue();

q.If_Empty();

q.dequeue();

q.dequeue();

q.If_Empty();

q.dequeue();

}