error: invalid initialization of non-const reference of type ‘int&’ from an rvalue of type ‘int’

Question

Wrong form:

int &z = 12;

Correct form:

int y;
int &r = y;

Question:

Answer 1

References are "hidden pointers" (non-null) to things which can change (lvalues). You cannot define them to a constant. It should be a "variable" thing.

EDIT::

I am thinking of

int &x = y;

as almost equivalent of

int* __px = &y;
#define x (*__px)

where __px is a fresh name, and the #define x works only inside the block containing the declaration of x reference.