Question

all the while, I am using dynamic_cast to determine Parent-Child relationship of an object.

#include <iostream>

class A {
public:
    virtual ~A() {}
};

class B : public A {
};

class C : public A {
};

int main()
{
    B b;
    std::cout<< typeid(b).name()<< std::endl;       // class B

    A* a = dynamic_cast<A *>(&b);
    if (a) {
        std::cout<< "is child of A"<< std::endl;    // printed
    }

    C* c = dynamic_cast<C *>(&b);
    if (c) {
        std::cout<< "is child of C"<< std::endl;    // Not printed
    }
    getchar();
}

May I know is it possible that I can determine parent-child relationship, of an object, through typeid? For example, how I can know B is the child of A, by using typeid checking?

Thanks.

Answer 1

I don’t think you can do that in current C++ using the information in typeinfo only. I know of boost::is_base_of (Type Traits will be part of C++0x):

if ( boost::is_base_of<A, B>::value ) // true
{
    std::cout << "A is a base of B";
}