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

I would look at the behavior of the built-in types.

When defining your own types it is preferable that the operators behave the same way as the built-in types. This allows easy adoption of your classes without having to dig into your code to see why they behave differently from expected.

So if we look at integers:

int main()
{
    int x = 5;
    int y = 6;
    int z = 7;

    (x = y) = z;
    std::cout << x << " " << y << " " << z << "\n";
}

This works with y unchanged and x being assigned 7. In your code i would expect your assignment operator to work the same way. The standard assignment operator definition:

Array& Array::operator=(Array const& rhs)
{
    /* STUFF */
    return *this;
}

Should do that just fine (assuming /* STUFF */ is correct).