Answer to Question #213894 in C++ for Anas

Question

a)     Can we declare base class constructor or destructor as virtual if yes then why we want to do?

b)    How we can declare a class as abstract and why we need abstract classes? 

Why we cannot able to create objects of abstract classes give reasonable justification of that.

Answer 1

a) A base class constructor cannot be declared as virtual.

A base class destructor can be declared as virtual. Virtual makes sure the destructor starts at the top instead of the middle

b)

Abstract class helps in information hiding

class Shape {
    public:

      // creating a pure virtual function
      virtual void calculateArea() = 0;
}