STL begin() 2

badbegin2.cpp

std::vector<int> foo;

// Add an item before setting the iterator...
// Should work, right?
foo.push_back(2);
std::vector<int>::iterator iter = foo.begin();   

// Add another item
foo.push_back(3);  

// Use the iterator... oops!
while (iter != foo.end()) {
  std::cerr << *iter << "\n";
  ++iter;
}