I'm trying to use operator overloading to define the basic operations (+,-,*,/) for my polynomial class but when i run the program it crashes and my computer frozes.

Update3

Ok i successfully done the first two operations(+,-). Now at multiplication, after multiplying each term of the first polynomial with each of the second i want to sort the poly list descending and then if there are more than one term with the same power to merge them in only one term, but for some reason it doesn't compile because of the sort function which doesn't work.

Here's what I got:

polinom operator*(const polinom& P) const
{
    polinom Result;
    constIter i, j, lastItem = Result.poly.end();
    Iter it1, it2;
    int nr_matches;

    for (i = poly.begin() ; i != poly.end(); i++) {
         for (j = P.poly.begin(); j != P.poly.end(); j++)
              Result.insert(i->coef * j->coef, i->pow + j->pow);
    }

    sort(Result.poly.begin(), Result.poly.end(), SortDescending());

    lastItem--;

    while (true) {
        nr_matches = 0;

        for (it1 = Result.poly.begin(); it < lastItem; it1++) {
             for (it2 = it1 + 1;; it2 <= lastItem; it2++){ 
                  if (it2->pow == it1->pow) {
                      it1->coef += it2->coef;
                      nr_matches++;
                  }
             }

             Result.poly.erase(it1 + 1, it1 + (nr_matches + 1));
        }       

    return Result;
}

Also here's SortDescending:

struct SortDescending
{
    bool operator()(const term& t1, const term& t2)
    { 
        return t2.pow < t1.pow; 
    }
};

What did i do wrong?

Thanks!