copies vs references in c++

see copies vs references for more programming languages.

In c++ everything is a copy by default. putting & after a type is referencing instead of making a copy

copy:

b = 1
const auto a = b;
b = 2
 
then a == 1

---

reference:

 
b = 1
const auto& a = b;
b = 2
 
a == 2