creare afisare lista dubla

#include <iostream>
#include <fstream>

using namespace std;

ifstream f("date.in");

struct nod
{
    int info;
    nod *st,*dr;
};

nod *prim,*ultim;

void creare()
{
    nod *nou;
    int x;
    while (f>>x)
        if (prim==NULL)
        {
            prim=new nod;
            prim->info=x;
            prim->st=NULL;
            ultim=prim;
        }
        else
        {
            nou=new nod;
            nou->info=x;
            ultim->dr=nou;
            nou->st=ultim;
            ultim=nou;
        }
        ultim->dr=NULL;
}

void parcurgere_st_dr()
{
    nod *p=prim;
    while (p)
    {
        cout<<p->info<<" ";
        p=p->dr;
    }

}

void parcurgere_dr_st()
{
    nod *p=ultim;
    while (p)
    {
        cout<<p->info<<" ";
        p=p->st;
    }
}

int main()
{
   creare();
   parcurgere_st_dr();
   cout<<'\n';
   parcurgere_dr_st();
    return 0;
}