C++challenge question

Question

Came across this code today and trying to understand why this is not an error.
https://code.sololearn.com/c1ad97CbAVrE/?ref=app

The const int &b is passed a value during the function call, so being declared a const it should not change? However, during the a*=b operation it changes. Although it is declared as a const it is referencing the location of the value passed from the calling variable?

Answer 1

a*=b will only change the value of a that is not const variable.
so no error will be thrown by compiler bro.
🤗🤗

Answer 2

const int &b here it not making b constant. Values passed is stored in the locations of a, b from function call. Locations are already constants, so const int &b is same as int &b.. So you can't changing location value.

Check this code as
const int b;
b++; //now this will be error.