Effective STL 45

count the elements in sequential container

vector<Widget> vw;...sort(vw.begin(), vw.end());typedef vector<Widget>::iterator VWIter;typedef pair<VWIter, VWIter> VWIerPair;VWIterPair p = equal_range(vw.begin(), vw.end(), w);cout << "There are " << distance(p.first, p.second) << "elements in vw equivalent to w";