What is a "pure virtual" member function?, C++ FAQ

C++ FAQ

From Marshall Cline: Bjarne Stroustrup, Herb Sutter, Andrei Alexandrescu, Pearson / Addison-Wesley Publishers and I collaborated to create a new C++ Super-FAQ! It's a team effort, with huge contributions from each of us and with amazing support from dozens of brilliant editors. The result is "awesomer" than ever! I originally wrote/published the FAQ in 1991 and now look forward to this new phase - and to continue working with it for another 20 years!

On a personal note, I'm at Oculus VR and it is amazing - fabulous people doing fabulous work. We're hiring more fabulous people so write me if that's you!

FAQ: What is a "pure virtual" member function? ←(in the new Super-FAQ)

It's in Section: Inheritance — abstract base classes (ABCs):

FAQ: What's the big deal of separating interface from implementation?
FAQ: How do I separate interface from implementation in C++ (like Modula-2)?
FAQ: What is an ABC?
FAQ: What is a "pure virtual" member function? (this FAQ)
FAQ: How do you define a copy constructor or assignment operator for a class that contains a pointer to a (abstract) base class?