Class A contains class B instances. When Class B's member functions are executed, the address of Class A is dynamically obtained.

When looking at <com essence>, there is a small problem: if Class A contains class B instances, Class A dynamically obtains the address of Class A when class B's member functions are executed.

After thinking for a while, I wrote the instance Code as follows:

Class Croom
{
Public:

Class bed
{
Public:
Int m_member1;
Int m_member2;
};

Class door
{
Public:
Int m_member1;

Void open ()
{
Cout <"open operation" <Endl;
}

Int getparentclsthispointer ()
{
Croom * plobj = NULL;

Int lioffset = reinterpret_cast <int> (& plobj-> mdoor); // obtains the offset of A Class door instance in a Croom instance.
Int liparentclsthispointer = reinterpret_cast <int> (this)-lioffset; // obtain the address of the Croom instance.

Return liparentclsthispointer;
};
};

Bed mbed;
Door mdoor;
};

Class Croom contains an instance of the door class.GetparentclsthispointerDynamically obtain the address of the class Croom instance.