please explain output 1(how?) code is given in description.

Question

#include<iostream>
using namespace std;
class A{};
int main()
{ A a;
cout<<sizeof(a);
return 0;
}

Answer 1

www.stroustrup.com/bs_faq2.html#sizeof-empty
I hope this helps, but it's basically there cause you still need to distinguish objects between one another