Ссылка на неразрешённый внешний символ

#include <iostream>
using namespace std;
 
class list
{
 
public:
    double f;
    list* first;
    list* last;
    list* next;
    list(double a);
    list();
    void Add(double a,list thisList)
    {
        //list* currelement = new list();
        //(*currelement).first = thisList.first;
        //thisList.last->next = currelement;
        //currelement->last = currelement;
        //thisList.last = currelement;
        //currelement->next = NULL;
        //currelement->f = a;
        list currelement;
        currelement.first = thisList.first;
        thisList.last->next = &currelement;
        currelement.last = &currelement;
        thisList.last = &currelement;
        currelement.next = NULL;
        currelement.f = a;
 
    }
    void Add(double a, bool index, list thisList)
    {
        list * currelement = new list();
        (*currelement).first = thisList.first;  
        currelement->last = thisList.last;
        currelement->next = thisList.next;
        thisList.next = currelement;        
        currelement->f = a;
 
    }
    ~list();
 
private:
 
};
 
list::list(double a)
:f(a)
{
    first = this;
    last = this;
    next = NULL;
}
 
list::~list()
{
    delete this;
}
 
void main()
{
    int n = 0,
        a = 0;
    cin >> n>>a;
    list mylist(a);
    for (int i = 1; i < n; i++)
    {
        cout << i << " ";
        cin >> a;
        mylist.Add(a,mylist);
    }
    list *currpointer = mylist.first;
    for (int i = 0; i < n; i++)
    {
        cout << currpointer->f << " ";
        currpointer = currpointer->next;
    }
    system("PAUSE");
}