[C++]Lista simpla, dubla, circulara

/* Lista dubla */
void creare() {
    p = new nod;
    prim = p;
    cout<<"Dati informatia nodului: ";
    cin>>p->info;
    p->urm = NULL;
    while(p->info != 0) {
        u = new nod;
        cout<<"Dati informatia: ";
        cin>>u->info;
        p->urm = u;
        p = u;
    }
        p->urm = NULL;
}

void afis_sd() {
    p = prim;
    while(p->urm != NULL) {
        cout<<p->info<<" ";
        p = p->urm;
    }
}
/* ******************************************* */
/* Lista dubla */
void creare()
{
    p = new nod;
    prim = p;
    cout << "Dati informatia nodului: ";
    cin >> p -> info;
    p -> ant = NULL;

    while(p -> info) {
        u = new nod;
        cout << "Dati informatia nodului: ";
        cin >> u -> info;
        p -> urm = u;
        u -> ant = p;
        p = u;
    }
    p -> urm = NULL;
}

void afisare_sd() {
    p = prim;
    while(p -> urm != NULL) {
        cout << p -> info << " ";
        p = p -> urm;
    }
}

void afisare_ds() {
    p = u -> ant;
    while(p != NULL) {
        cout << p -> info << " ";
        p = p -> ant;
    }
}
/* ******************************************* */
/* Lista circulara */
void creare()
{
    p = new nod;
    cout << "Dati informatia nodului: ";
    cin >> p -> info;
    p -> urm = NULL;
    prim = p;
    while(p -> info) {
        u = new nod;
        cout << "Dati informatia nodului: ";
        cin >> u -> info;
        p -> urm = u;
        p = u;
    }
    p -> urm = prim;
}

void afisare_sd() {
    p = prim;
    while(p -> urm != u -> urm) {
        cout << p -> info << " ";
        p = p -> urm;
    }
}
/* ******************************************* */