Odd values printed when dereferencing the end iterator of a vector

Question

I have a vector storing {1,2,3,4,5}. I tried to print *(vec.end()) and got back the result 6. I don\'t know how to explain this. Similarly, calling vec.fi

Answer 1

This line invokes undefined behavior:

std::cout << *(set1.end()) << std::endl;

It is undefined behavior to dereference the end() iterator. Thus anything can be expected.