Question

Say you have a sub class B which inherits from super class A. You want a function that can accept either A or B.

template <typename T>
void someFunc(T* pObj, bool someOtherArg)
{
    pObj->AnInheritMethod();
    if (pObj->IsASub())
    {
       pObj->ANonInhertMethod();
    }
}

When I compile this (Visual Studio 6) I get:

error C2065: 'pObj' : undeclared identifier

Am I way off base here?

Answer 1

You don’t need a function template for this; the following will do just fine:

void someFunc(A* pObj)
{
    pObj->AnInheritMethod();
    if (B* pObjAsB = dynamic_cast<B*>(pObj))
    {
        pObjAsB->ANonInheritMethod();
    }
}

Or, if you prefer to use your IsASub() member function instead of dynamic_cast:

void someFunc(A* pObj)
{
    pObj->AnInheritMethod();
    if (pObj->IsASub())
    {
        B* pObjAsB = static_cast<B*>(pObj);
        pObjAsB->ANonInheritMethod();
    }
}

Aside from the missing return type, I don’t see anything obviously wrong with the code in your example; I don’t have Visual C++ 6 installed to check.