#include <deque>
#include <iostream>

int main()
{
    std::deque<int> x(10);
    std::deque<int>::iterator z = x.end();
    
    // this should invalidate iterators pointing to the last element
    // and iterators pointing to the end()
    x.erase(x.end() - 1);
    // The following cause the same problem
    // x.erase(x.end() - 1, x.end());
    // x.pop_back();
    
    std::cout << "How can the difference between two valid iterators: "
        << z - x.begin() << " exceed the size of the container: "
        << x.size() << " ?" << std::endl;
    
    return 0;
}