CODEWITHSUNDEEP
c++visual-studio-2013
user3720957
user3720957

Reputation: 173

C++:why base pointer and derived pointer point to the same address in vs2013?

class A{
    int a;
};
class B : public  A{
    int b;
};
class C : public  B{
    int c;
};

int _tmain(int argc, _TCHAR* argv[]){
    C c;
    C* pc = &c;
    B* pb = &c;
    A* pa = &c;
    printf("%d\n", pc); //4344
    printf("%d\n", pb); //4344
    printf("%d\n", pa); //4344
    return 0;
}

All(pa,pb,pc) point to the same address "4344" , aren't they suppossed to be different?

-------------UPDATE-------------
If they are suppossed to be the same ,then when I change the code to this , pa would point to different address :

class A{
    int a;
};
class B {
    int b;
};
class C : public  B , public A{
    int c;
};

int _tmain(int argc, _TCHAR* argv[]){
    C c;
    C* pc = &c;
    B* pb = &c;
    A* pa = &c;
    printf("%p\n", pc); //4344
    printf("%p\n", pb); //4344
    printf("%p\n", pa); //4348
    return 0;
}

How to explain these?

Upvotes: 1

Views: 120

Answers (2)

Saeb Amini
Saeb Amini

Reputation: 24439

You are assigning all pointers to the same address:

C* pc = &c;
B* pb = &c;
A* pa = &c;

I'd say that makes it very clear that they should be the same.

Upvotes: 0

shiv
shiv

Reputation: 1952

No they are pointing to the same object i.e. c. Thus you will have same address. And you should not print addresses as %d but %p. https://10hash.com/c/stdio/#fprintf or even better http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html

Upvotes: 1

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