in C++: Is const reference means “read-only view of” or it requires immutability of object being referenced?

Question

The question can be formulated by example as following: is this snippet of code valid?

int a = 1;
const int& ca = a;
++a; //< Q: Is this valid?
cout &         


        

Answer 1

As a reference is just another name to a variable and not the object itself, yes in the snippet you show it can be thought as a read-only reference. The code provided with the reference can only access it but it does not guarantee that the object itself won't be changed in another place of your program.