References referring to other reference & pointer to reference

Question

I was going through the C++ Primer book and I came across the following two statements:

1. Because references are not objects, we may not define a reference to a reference.

2. Because references are not objects, they don’t have addresses. Hence, we may not define a pointer to a reference.

However, when I run the following code, I don't get errors or warnings and my code runs fine:

int main(int argc, const char * argv[]) {
    // insert code here...

    int i, &ri = i;
    int &bi = ri;

    std::cout << "The address of ri is " << &ri << std::endl;
    std::cout << "The address of bi is " << &bi << std::endl;

    int* p = &ri;
    std::cout << p << std::endl;

    return 0;
}

Output:

The address of ri is 0x7fff5fbff76
The address of bi is 0x7fff5fbff76c
0x7fff5fbff76c

Any idea why this works?

Thanks.

Answer 1

What they mean is that you can't have a int& & type.

In your code, the reference ri is referring to the object i.

And when you do int &bi = ri; you're not making a reference to a reference, but you're making a reference to that same object once again.

Answer 2

In the above code, you have not created any kind of variable to hold the address of reference.

Logical meaning to hold address of reference in your code will be:

int &bi = &ri;

but this code gives error.

And hence your code is working, because you have created variables, all of which hold address of variable i.

Answer 3

int &bi = ri;

this means "set the reference bi equal to the reference ri". In the same way as you assign any other simple type.

int* p = &ri;

the clever compiler substitutes the "address of reference" with the "address of the object the reference references to".