What mistake prevents the following class declaration from functioning properly as an abstract class?

Question

class Shape
{
public:
virtual double print() const;
double area() const { return base * height; }
private:
double base;
double height;
};

a. There are no pure virtual functions.
b. There is a non-virtual function.
c. private variables are being accessed by a public function.
d. Nothing, it functions fine as an abstract class.

Answer 1

a. There are no pure virtual functions.