Why can I not assign memory address of a variable to another memory address of a variable?

Question

I am trying to assign a memory address of a variable to other variable's memory address.

For example:
int a;
int &b=a;//I can do that.

But I can't do that:
int a; int b;
&b=&a;

Why can I not do that?

Answer 1

Because &b is not a variable. It's just like you can't assign to -x or to (2*a).

You can store memory addresses in variables like int *b = &a;

Answer 2

In addition to Schindlabua's nice illustration, see this comprehensive article about "lvalue and rvalue".

[https://eli.thegreenplace.net/2011/12/15/understanding-lvalues-and-rvalues-in-c-and-c#]