I have a question about c++ Please, monsters

#include <iostream>
#include <string>
using namespace std;
class StringNode {
private:
    string elem;
    StringNode* next;
friend class StringLinkedList;
};
class StringLikedList {
public:
    StringLikedList() :head(NULL) {};
    ~StringLikedList() {
        while (!empty())removeFront();
    };
    bool empty()const { return head == NULL; };
    const string& front()const {
        return head->elem;
    };
    void addFront(const string& e) {
        StringNode* v = new StringNode;
        v->elem = e;
        v->next = head;
        head = v;
    };
    void removeFront() {
        StringNode* old = head;
     head = old->next;
        delete head;
    };
private:
    StringNode* head;
};
int main()
{
    system("pause");
    return 0;
}