Template clase Lista

#include <iostream>
using namespace std;

/*---------------------------------------------------*/

template <typename T>
class nodo {

    friend class lista;

    private:
            T valor;
            nodo<T> *sig;

    public:
    nodo(T val){ valor = val; sig = 0; }
};

/*---------------------------------------------------*/

template <typename T>
class lista {

    private:
            nodo<T> * list;

    public:
            lista();
            void insertar(T valor);
            void visualizar();
};

/*---------------------------------------------------*/

template <typename T>
lista<T>::lista()
{
    list = 0;
}

/*---------------------------------------------------*/

template <typename T>
void lista<T>::insertar(T valor)
{
    nodo<T> * nuevo = new nodo<T>(valor);

    if (list == 0)
        list = nuevo;
    else
    {
        nuevo->sig = list;
        list = nuevo;
    }
}

/*---------------------------------------------------*/

template <typename T>
void lista<T>::visualizar()
{
    nodo<T> * it = list;
    while (it != 0)
    {
        cout<< it->valor<< " ";
        it = it->sig;
    }
}

/*---------------------------------------------------*/

int main()
{
    lista<int> l;
    l.insertar(1);
    return 0;
}

/*---------------------------------------------------*/