Class Templates and inheritance

Question

How should this template based class declaration be read?

I understand that a class can inherit from another class that's based on a template, but here it seems the class MyClass is directly inheriting from the template type B.

 template <typename A, typename B>
     
     class MyClass final : public B {
        using XX = B;
    
        /*
            Rest of the class definition
        */
      }

yes, `MyClass` inherits from `B`. You already answered your question. What is confusing you? — 463035818_is_not_an_ai, Oct 27 '20 at 20:02
Do you have any problems with that code (besides the missing `;` after the class definition)? I can't spot a question in your question. — πάντα ῥεῖ, Oct 27 '20 at 20:03
`B` could very well be a template class. This definition doesn't preclude that. — tadman, Oct 27 '20 at 20:04
"...s directly inheriting from the template type B." do you mean "... from the template parameter B" ? or do you mean `B` itself is a template? — 463035818_is_not_an_ai, Oct 27 '20 at 20:06
@idclev463035818 . That's what I'm wondering. The above MyClass declaration feels a bit circuitous (C++ noob alert) with B being a typename, which is also being inherited from. Where's the definition of B? — eternal_learner, Oct 27 '20 at 20:22
@eternal_learner It comes from the instantiation of the template. `MyClass` would inherit from `MyOtherClass`. — molbdnilo, Oct 27 '20 at 20:42
When you've wrapped your head around this, you can progress to the truly mind-bending: https://stackoverflow.com/questions/4173254/what-is-the-curiously-recurring-template-pattern-crtp — Jerry Coffin, Oct 30 '20 at 03:55
Thanks for sharing that @JerryCoffin. I'll certainly give reading that a shot. — eternal_learner, Oct 30 '20 at 06:05

Class Templates and inheritance

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