Question

If you have class B which inherits from class A, the two values printed below might be different. Why?

B *myPointer = new B();
A *myOtherPointer = myPointer;

printf(“%x”, myPointer);
printf(“%x”, myOtherPointer);

Answer 1

the two values printed below might be different. Why?

Assuming that A is a base of B so that the assignment is valid, it might not be the only base of B (and in particular it might not be the first base), in which case there will be an offset:

struct A { int x; };
struct A_ { int y; }
struct B : A_, A {};
int main() {
   B b;
   assert( static_cast<void*>(&b) != static_cast<void*>(static_cast<A*>(&b)) );
}

Additionally, if the inheritance relationship is virtual then they will not start at the same address either:

struct A {};
struct B : virtual A {};
int main() {
   B b;
   assert( static_cast<void*>(&b) != static_cast<void*>(static_cast<A*>(&b)) );
}