Cognizant Polymorphism Quiz

A pure virtual function does not have a definition corresponding to base class.

Syntax for Pure Virtual Function is virtual void show() = 0;

Dynamic binding or late binding is the mechanism a computer program waits until runtime to bind the name of a method called to an actual subroutine. It is an alternative to early binding or static binding where this process is performed at compile-time

We can’t create pointers to an abstract class.

A virtual function is a member function which is declared within a base class and is re-defined(Overriden) by a derived class. When you refer to a derived class object using a pointer or a reference to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.

• Virtual functions ensure that the correct function is called for an object, regardless of the type of reference (or pointer) used for function call.


• They are mainly used to achieve run time polymorphism.


• Functions are declared with a virtual keyword in base class.


• The resolving of function call is done at Run-time.


• They cannot be friend


• They must be non static member function of a class.


• Constructor function cannot be virtual.

In programming languages, ad hoc polymorphism is a kind of polymorphism in which polymorphic functions can be applied to arguments of different types, because a polymorphic function can denote a number of distinct and potentially heterogeneous implementations depending on the type of argument(s) to which it is applied.

For cout the over load >> operator

Operators that cannot be overloaded in C++

•  “.” Member access or dot operator.


•  “? : ” Ternary or conditional operator.


•  “::” Scope resolution operator.


•  “. *” Pointer to member operator.


•  “ sizeof” The object size operator.


•  “ typeid” Object type operator.

The overloaded << operator function must then be declared as a friend of class Date so it can access the private data within a Date object.

When a virtual function is initialized with zero it is called a pure virtual function.