#include <cstddef>
#include <iostream>

#define eol "\n"
using namespace std;

class LinkedList{
    // Struct inside the class LinkedList
    // This is one node which is not needed by the caller. It is just
    // for internal work.
    struct Node {
        int x;
        Node *next;
    };

// public member
public:
    // constructor
    LinkedList(){
        head = NULL; // set head to NULL
    cur = NULL;
    }

    // This prepends a new value at the beginning of the list
    void addValue(int val){
        Node *n = new Node();   // create new Node
        n->x = val;             // set value
        n->next = head;         // make the node point to the next node.
                                //  If the list is empty, this is NULL, so the end of the list --> OK
        head = n;               // last but not least, make the head point at the new node.
    if( cur == NULL)
        cur = head;
    }

    void rewind(){
        cur = head;
    }
    void next(){
        if( cur != NULL )
            cur = cur->next;
    }
    int getValue(){
        if( cur != NULL )
            return cur->x;
        return 0; // really we should raise exception
    }
    int hasValue(){
        return ( cur != NULL ? true : false );
    }

// private member
private:
    Node *head; // this is the private member variable. It is just a pointer to the first Node
    Node *cur;
};

int main() {
    LinkedList list;

    list.addValue(5);
    list.addValue(10);
    list.addValue(20);
    list.rewind();

    while( list.hasValue()){
        cout << "Value: " << list.getValue() << eol;
        list.next();
    }
    list.rewind();
    while( list.hasValue()){
        cout << "Value: " << list.getValue() << eol;
        list.next();
    }
    return 0;
}