You derive your class from vector and map so class have both begin() and end() inherited from vector and the map. It actually does not make any sense but the syntax is this:
class cfoobar : public std::vector<int>, public std::map<int, int>
{
public:
void foobar()
{
for (std::vector<int>::iterator it = std::vector<int>::begin(); it != std::vector<int>::end(); it++)
{
}
}
};