void SapXepTen(List &L)
{
NV S;

NV *min, *p, *q;
p = L.first;
while (p != L.tail)
{
q = p->next; min = p;
while (q != NULL)
{
if(strcmp (q->ten, min->ten) <0)
min = q;

q = q->next;}
swap(min->ten, p->ten);
p = p->next;
}OutputNV(L);
}