Verify base object is of a particular derived type

Question

I have a Visual Studio 2008 C++03 project where I would like to verify if an object is of a certain type.

For example:

int main()
{
    struct A { virtual ~A() { }; };
    struct B : public A { };
    struct C : public A { };

    A* b = new B();
    A* c = new C();

    assert( typeof( b ) == typeof( B ) );
    assert( typeof( b ) != typeof( C ) );

    assert( typeof( c ) == typeof( C ) );
    assert( typeof( c ) != typeof( B ) );

    assert( typeof( b ) != typeof( c ) );
    return 0;
}

Is there a way to do this in C++03? How?

score 1 · Answer 1 · answered May 22 '12 at 16:01

1

You can use dynamic_cast to attempt to cast it to a base/derived type. If it does not return NULL then it is a base class or derived from that type (depending if you cast up the hierarchy or down)

answered May 22 '12 at 16:01

Casey

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assert( NULL != dynamic_cast< B* >( b ) );` Yup. that works too. Thanks! – PaulH May 22 '12 at 16:55

score 0 · Accepted Answer · edited May 23 '17 at 12:27

0

You can use typeinfo for getting the type of an object.
Or you could use dynamic_cast to check if an pointer points to object of appropriate type.

edited May 23 '17 at 12:27

Community

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1

answered May 22 '12 at 16:01

Alok Save

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`assert( typeid( *b ) == typeid( B ) )` appears to work. Thanks! – PaulH May 22 '12 at 16:51

Verify base object is of a particular derived type

2 Answers2