Do postfix operators return lvalue when applied on ostream_iterator?

Question

Isn't the foll code given in C++ Primer incorrect ?

ostream_iterator<int> out_iter(cout, " ");
for (auto e : vec)
    *out_iter++ = e;  // the assignment writes this element to cout
cout << endl;

The postfix operator returns the old value, not a reference then how can it be made to act as an lvalue ?

Please correct if I am wrong

Answer 1

According to reference http://en.cppreference.com/w/cpp/iterator/ostream_iterator/operator_arith

ostream_iterator& operator++();

ostream_iterator& operator++( int );

but operator* and operators ++ of ostream_iterator do nothing, they only return reference to *this, so you can write this

for (auto e : vec)
    out_iter = e;  // the assignment writes this element to cout

and the output will be the same.