C++ why the assignment operator should return a const ref in order to avoid (a=b)=c

Question

I am reading a book about C++ and more precisely about the operator overloading.

The example is the following:

const Array &Array::operator=(cons         


        

Answer 1

As far as I know, assignment operators do not return const references in idiomatic C++. The Standard types do not return const references either.

std::string a, b, c;
(a = b).clear(); // no objection from compiler

All of my custom assignment operators have returned a non-const reference.

When in doubt, check the Standard library. It's not flawless, but it definitely gets basic things like this correct.