I have created this program about Linked List and I have included several functions: Add, Display and Sort.

Could you suggest me on how to make my code better and also suggest me what functions to include as well in the future?

Here is my code:

#include <iostream>
using namespace std;
// ----------------------------------------------------
class Node {
private:
    int value;
    Node *next;
public:
    Node(int v) { value = v; next = NULL; }
    void Add(int v);
    void Print();
    void SortValues();
    void SortNodes();
};
// ----------------------------------------------------
void Node::Add(int v)
{
    Node *newItem = new Node(v);
    Node *temp = this;
    while (temp->next != NULL)
        temp = temp->next;
    temp->next = newItem;
}
void Node::Print()
{
    Node *temp = this;
    while (temp != NULL)
    {
        cout << "  " << temp << " : " << temp->value << endl;
        temp = temp->next;
    }
}
void Node::SortValues()
{ 
    Node *swapCandidate = next;
    Node *current;
    Node *min;
    //    L* temp;
    // Look at every value
    while (swapCandidate != NULL)
    {
        current = swapCandidate;
        min = swapCandidate;
        // ------------------------------
        while (current != NULL)
        {
            if (current->value < min->value)
            {
                min = current;
            }
            current = current->next;
        }
            if(min != swapCandidate)
            {
                int tempV = min->value;
                min->value = swapCandidate->value;
                swapCandidate->value = tempV;
            }
         // ------------------------------
         swapCandidate = swapCandidate->next;
         }
     }
     // ----------------------------------------------------
void main()
{
// Sort - moving values
Node *myList = new Node(0);
myList->Add(15);
myList->Add(3);
myList->Add(20);
myList->Add(1);
myList->Print();
myList->SortValues();
cout << "------------------------------" << endl;
    myList->Print();
system("pause");
}