Question

Or will the address a be equal to the integer that b references?

Or will something else happen?

Edit: Also, if double *a = 3.0, does a point to 3.0?

Answer 1

If the code is int *a = *b; then *b is a pointer to an integer (has to match the type of a). That means that b is a pointer to a pointer to an integer. a would then contain the address that *b is pointing to, not to the address that b is pointing to.

However, if the code is int *a; *a = *b; then that’s different. In that case you are copying the object that b is pointing to into the address that a is pointing to. The object has to be an integer, so a will point to a copy of the integer (so you could change *b and *a will not change). By the way, If a in uninitialised, that would be undefined behaviour (very likely a crash).