Derived template-class access to base-class member-data

Question

This question is a furtherance of the one asked in this thread.

Using the following class definitions:

template 
class Foo {

public:
         


        

Answer 1

Appears to work fine in Visual C++ 2008. I've added some dummy definitions for the types you mentioned but gave no source for. The rest is exactly as you put it. Then a main function to force BarFunc to be instantiated and called.

#include 

class streamable {};
std::ostream &operator<<(std::ostream &os, streamable &s) { return os; }

class foo_arg_t : public streamable {};
class a_arg_t : public streamable {};
class b_arg_t : public streamable  {};

template 
class Foo {

public:
    Foo (const foo_arg_t foo_arg) : _foo_arg(foo_arg)
    {
        /* do something for foo */
    }
    T Foo_T;        // either a TypeA or a TypeB - TBD
    foo_arg_t _foo_arg;
};

template 
class Bar : public Foo {
public:
    Bar (const foo_arg_t bar_arg, const a_arg_t a_arg)
    : Foo(bar_arg)   // base-class initializer
    {

        Foo::Foo_T = T(a_arg);
    }

    Bar (const foo_arg_t bar_arg, const b_arg_t b_arg)
    : Foo(bar_arg)
    {
        Foo::Foo_T = T(b_arg);
    }

    void BarFunc ();

};

template 
void Bar::BarFunc () {
    std::cout << _foo_arg << std::endl; 
    std::cout << Bar::_foo_arg << std::endl;   
}

int main()
{
    Bar *b = new Bar(foo_arg_t(), a_arg_t());
    b->BarFunc();
}