Question : how to re-assign a class member in c++ (override its value by pointer)

hello,

i think the title is not very clear. let me explain: say, i have 2 classes by

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class B
{
public:
	int BNum;
};

class A
{
public: 
	int ANum;
	B *bMember;
	A(int num)
	{
		ANum = num;
		bMember = new B();
		bMember->BNum = num +10;
	}
	A(B* bb) : bMember(bb)
	{
		ANum = bMember->BNum -20;
	}
	~A()
	{
		delete bMember;
	}
};

and when i create a pointer to A class i can override its ANum member.

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int *inta, *intb;
A *aa1 = new A(20);
intb = &aa1->ANum;
inta = new int(100);
*intb = *inta;
cout << aa1->ANum << endl;
cout << *inta << endl;
cout << *intb << endl;

the output is

but things get interesting when i intend to override the b member of class A

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B *ba,*bb, *bc;
bc = new B(); bc->BNum = 1000;
A* aa2 = new A(bc);
bb = aa2->bMember;
ba = new B(); ba->BNum = 200;
*bb = *ba;
cout << aa2->ANum << endl;
cout << ba->BNum << endl;
cout << bb->BNum << endl;
cout << bc->BNum << endl;

output :

even the value held by bc changes. but nothing happens to bMember.
the reason for using dummy pointers that, in my application, actually i use vectors of pointers to a field of some type, of my main class. how can i override this field using the pointer contained in my vector. maybe the problem occurs because of my bad design, but i am curious about the situation above. (1000,200,200 ...)
any comments appreciated.
thanks

Answer : how to re-assign a class member in c++ (override its value by pointer)

>> even the value held by bc changes. but nothing happens to bMember.

Of course something happens to bMember : you overwrite it here :

>> bb = ba;

bb points to the same B object as aa2->bMember, ie. both point to the object that bc points to.

So, when you dereference the bb pointer (bb), you get that object (the same object that all the three mentioned pointers point to).
When you then assign ba to that object, you overwrite it with the new data. This means that all three mentioned pointers will now point to that overwritten object.

I must say though that you're doing some really crazy stuff here. What's the point of all of this code ? It seems highly error prone, and unnecessarily complicated.