Question

What is a pure virtual function in C++?

(a) A virtual function defined in a base class

(b) A virtual function declared in a base class

(c) Any function in a class

(d) A function without definition in a base class

The question was asked during an interview.

My enquiry is from Abstract Classes in chapter Derived Classes, Templates & Exception Handling in C++ of C++

Answer 1

Right answer is (b) A virtual function declared in a base class

The explanation is: Pure virtual function is a virtual function which has no definition/implementation in the base class.