Question

using namespace std;
class myList
{
  public:
    mylist():_internalList(),_lastPostition(0)
  {
  }
    typedef list<string>::iterator Itr;
    bool enqueue(string);
    Itr next()
    {
      if(_lastPostition == 0)
        _lastPostition = _internalList.begin();
      if(_lastPostition == _internalList.end())
        return (_lastPostition = 0);
      return _lastPostition++;
    }
  private:
    list<string> _internalList;
    Itr _lastPostition;
}

enqueue is not push_back, it inserts based on some custom logic.
I can’t use std::set and overload operator <, because my insertion logic isn’t transitive – ( a < b && b < c) does not imply a < c.

This works but I’m not sure if its an undefined behavior.
Is it safe to assign 0 to an iterator and check for 0 ?

Answer 1

“Is it safe to assign 0 to an iterator and check for 0 ?” No.