iterator_traits

Been trying to read this book:

Abraham, David; Gurtovoy, Aleksey. 2004. C++ template metaprogramming: Concepts, tools, and techniques from Boost and beyond. Addison Wesley.

Tried to code a little on iterator_traits:

When I run it:

kuyu@castor-ub:~/dkuyu/practice/cpp/iterator_traits$ g++ iterator_traits.cpp && ./a.out 
Before:
a = a
b = b
After:
a = b
b = a
kuyu@castor-ub:~/dkuyu/practice/cpp/iterator_traits$