c++ references appear reassigned when documentation suggests otherwise

Question

According to this question you can\'t change what a reference refers to. Likewise the C++ Primer 5th Edition states

Once we have defined a reference,

Answer 1

You are not reassigning a reference. A reference acts as an alias for a variable. In this case, ref is an alias for a, so

ref = b;

is the equivalent of

a = b;

You can easily check that by printing out the value of a:

std::cout << a << std::endl; // prints 4