#include <iostream>
#include <string>
using namespace std;

class Cnode
{
    int value;
    Cnode *next;
    friend class Clist;
    friend class linkedQueue;
};

class Clist
{
public:
    Clist();
    ~Clist();
    bool empty() const;
    int size() const;
    const int& front() const;
    const int& back() const;
    void advance();
    void add(const int& e);

    void remove();
private:
    Cnode *cursor;
    friend class linkedQueue;
};

class linkedQueue
{
public:
    linkedQueue();
    int size() const;
    bool empty() const;
    const int& front() const;
    void enqueue(const int& e);
    void dequeue();
    void display();
    void showFront();
    int count();
private:
    Clist C;
    int n;
    
};

Clist::Clist()
{
    cursor = NULL;
}

Clist::~Clist()
{ while(!empty()) remove(); }

linkedQueue::linkedQueue()
: C(), n(0) {}

bool Clist::empty() const
{
    if(cursor == NULL)
        return true;
    else
        return false;
}

bool linkedQueue::empty() const
{ return n == 0; }

const int& linkedQueue::front() const
{
    if (empty())
        cout << "Queue is empty\n";
    return C.front();
}

const int& Clist::front() const
{
    if(empty())
        cout << "Queue is empty\n";
    return cursor-> next-> value;
}

const int& Clist::back() const
{
    if(empty())
        cout << "Queue is empty\n";
    return cursor-> value;
}

void Clist::advance()
{
    if(empty())
        cout << "Queue is empty\n";
    cursor = cursor-> next;
}

int main()
{
    linkedQueue Q;
    
    Q.enqueue(6);
    Q.enqueue(4);
    Q.enqueue(7);
    Q.showFront();
    cout << endl;
    Q.display();
    Q.dequeue();
    Q.display();
    Q.dequeue();
    Q.display();
    Q.enqueue(1);
    Q.dequeue();
    Q.display();
    Q.dequeue();
    Q.display();
    
    cout << endl;

    return 0;
}

void Clist::add(const int& e)
{
    Cnode *v = new Cnode;
    v-> value = e;
    v-> next = NULL;
    if(cursor == NULL)
    {
        v-> next = v;
        cursor = v;
    }
    else
    {
        v-> next = cursor-> next;
        cursor-> next = v;
    }
}

void linkedQueue::enqueue(const int& e)
{
    C.add(e);
    C.advance();
    n++;
}

void Clist::remove()
{
    //if(cursor-> next == cursor)
    Cnode *old = cursor-> next;
    if(old == cursor)
    {
        cursor = NULL;
    }
    else
    {
        /*Cnode *old;
        old = cursor;
        while(old-> next != cursor)
            old = old-> next;
        old-> next = cursor-> next;
        old = cursor;
        cout << "Number being removed is: " << old-> value;
        cout << endl;
        cursor = (old-> next == NULL ? NULL : cursor-> next);
        delete old;*/
        cursor-> next = old-> next;
    }
    cout << "Number being removed is: " << old-> value;
    cout << endl;
    delete old;
}

void linkedQueue::dequeue()
{
    if(empty())
    {
        cout << "Queue is empty\n";
        return;
    }
    C.remove();
    n--;
}

void linkedQueue::display()
{
    if(empty())
    {
        cout << "Queue is empty\n";
    }
    else
    {
        Cnode* temp = C.cursor-> next;
        for(int i = 1; i <= this-> count(); i++)
        {
            cout << temp-> value << " " << endl;
            temp = temp-> next;
        }
    }
}

int linkedQueue::count()
{
    Cnode *v;
    v = C.cursor;
    int c = 0;
    if(C.cursor == NULL)
        return 0;
    else
        c++;
    while(v-> next != C.cursor)
    {
        c++;
        v = v-> next;
    }
    return c;
}

void linkedQueue::showFront()
{
    if(empty())
        cout << "Queue is empty\n";
    else
        cout << "Number at front is: " << C.cursor-> next-> value;
}