#include<iostream>
using namespace std;

struct node{
    int data;
    struct node *next;
};
class Queue{
    node *front;
    node *rear;
public:
    Queue(){
        front = NULL;
        rear = NULL;
    }
    void createNode(int val){
        node *ptr;
        node *nn;
        nn = new node;
        ptr = front;
        nn->data = val;
        nn->next = NULL;
        front=nn;
        rear=nn;
    }
    void enqueue(int val){
        if(front==NULL || rear==NULL){
            createNode(val);
        }
        else{
            node *ptr;
            node *nn;
            ptr=front;
            nn = new node;
            nn->data = val;
            rear->next = nn;
            nn->next = front;
            rear = nn;
        }
    }
    void dequeue(){
        node *n;
        n = front;
        front = front->next;
        delete(n);
    }
    void traverse(){
        node *ptr;
        ptr=front;
        do{
            cout<<ptr->data<<" ";
            ptr=ptr->next;
        }while(ptr!=rear->next);
        cout<<front->data;
        cout<<endl;
    }
};
int main(void){
    Queue q;
    q.enqueue(10);
    q.enqueue(20);
    q.enqueue(30);
    q.enqueue(40);
    q.enqueue(50);
    q.enqueue(60);
    q.enqueue(70);
    q.traverse();
    q.dequeue();
    q.traverse();
    return 0;
}