Hello c++ Queue structure

main.cpp

#include <cassert>
#include <iostream>

#define STREAM std::ostream&

struct Player {
    int score;
    
    Player (int s) { this -> score = s; }
    Player ()      { this -> score = 0; }
        
    friend
    STREAM operator << (STREAM os, const Player& p) {
        os << "Player <" << p.score << ">\t";
        return os;
    }
};

/** Definition of the node */
template <class Object>
struct node {
    Object data;
    node<Object> *next;
};

/** Definition of the queue class */
template <class Object>
class queue {
 public:
    /** Show queue */
    void display() {
        node<Object> *current = queueFront;
        if (current == NULL) std::cout << "\n\t! [EMPTY queue] !" << std::endl;
        else {
            std::cout << "Front --> ";
            while (current != NULL) {
                std::cout << current->data;
                current = current->next;
            }
            std::cout << std::endl;
        }
        std::cout << "\tSize of queue: " << size << std::endl;
    }

    /** Default constructor*/
    queue() {
        queueFront = NULL;
        queueRear = NULL;
        size = 0;
    }

    /** Destructor */
    ~queue() {}

    /** Determine whether the queue is empty */
    bool isEmptyQueue() { return (queueFront == NULL); }

    /** Add new item to the queue */
    void enQueue(Object item) {
        node<Object> *newNode;
        newNode = new node<Object>;
        newNode->data = item;
        newNode->next = NULL;
        if (queueFront == NULL) {
            queueFront = newNode;
            queueRear = newNode;
        } else {
            queueRear->next = newNode;
            queueRear = queueRear->next;
        }
        size++;
    }

    /** Return the first element of the queue */
    Object front() {
        assert(queueFront != NULL);
        return queueFront->data;
    }

    /** Remove the top element of the queue */
    void deQueue() {
        node<Object> *temp;
        if (!isEmptyQueue()) {
            temp = queueFront;
            queueFront = queueFront->next;
            delete temp;
            size--;
        } else {
            std::cout << "Queue is empty !" << std::endl;
        }
    }

    /** Clear queue */
    void clear() { queueFront = NULL; }

 private:
    node<Object> *queueFront; /**< Pointer to the front of the queue */
    node<Object> *queueRear;  /**< Pointer to the rear of the queue  */
    int size;
};


int main() {
    std::cout << "Hello, Queue!\n";
    
    auto n = queue<Player>();
    
    Player p = Player(12);
    
    n.enQueue(p);
    n.enQueue(Player(14));
    
    n.display();
    
    n.deQueue(); n.display();
    n.deQueue(); n.display();
    
    return 0;
}