Modifying reference member from const member function in C++

Question

I am working on const-correctness of my code and just wondered why this code compiles:

class X
{
    int x;
    int& y;
public:
    X(int& _y):y(_y)
         


        

Answer 1

The situation is similar to pointer members. In a const member function, the const applies to the pointer itself, not the pointee.

It's the difference between:

X* const //this is how the const applies: you can modify the pointee
const X*

Except X& const isn't valid syntax, since the reference can't be made to refer to another object in the first place (they are implicitly always const). In conclusion: const on methods has no effect on member references.