What is the output of this code?

Question

int a = 42;
int& p = a;
p - = 8;
cout << a;

Answer 1

The answer is 34.
'&' makes variable p as the reference to an int a.
This means now, p and a points to the same memory location(But it's not that value of a is copied to p but p refers to memory address of a)

Updating value of reference variable updates the value of original variable too as they point to same memory location.
So p -= 8 is equivalent to a -=8 which is a = a - 8 producing 34 as the output

Answer 2

a = 42
p = a
p - = 8, p - 8 = a, 42 - 8 = a
a = 34