How to check if the iterator is initialized?

Question

If I use a default constructor for an iterator, how to check if it was assigned later on?

For pointers, I could do this :

int *p = NULL;
/// some code
         


        

Answer 1

In C++, uninitialized local variables can have any value i.e it contains simply garbage. That implies, you cannot check it against some well-defined value, to determine if the variable is uninitialized or not.

Not only that if the variable is not initialized and you write this:

if ( NULL == it ) // this fails

then it invokes undefined behavior.