#include <iostream>

using namespace std;

//Queue with List

 struct node
{
        int data;
        struct node *link;
};

struct node *front=NULL;
struct node *rear=NULL;

void enqueue(int x)
{
    struct node  *N = new node;
    N->data=x;
    N->link=NULL;

    if(rear==NULL)
    {
        rear=N;
        front=N;
    }

    else
    {
        rear->link=N;
        rear=rear->link;
        rear->link=front;
    }

}

void dequeue()
{
    if(front==NULL)
    {
        cout<<"No values in queue"<<endl;
    }

    else
    {
        if (front==rear)
        {
            front=NULL;
            rear=NULL;
        }

        else
        {
            front=front->link;
        }

    }
}

 void display()
    {
        struct node *t =front;
        while(t!=rear)
        {
            cout<<t->data<<"->";
            t=t->link;
        }
        cout<<t->data<<endl;
    }

int main()
{
    enqueue(10);
    enqueue(20);
    enqueue(30);
    enqueue(40);
    display();
    dequeue();
    display();

        return 0;
}