Pure Virtual Function in C++ with Example Program

Declare a function virtual inside the base class and redefine it in the derived classes. The function inside the base class is seldom used for performing any task.
Example :

 
virtual void display()=0;

such functions are called Pure Virtual Functions. It only serves as a placeholder. It is also called “do-nothing” functions.
A pure virtual function is a function declared in a base class that has no definition relative to the base class.

Program:

#include<iostream.h>
#include<conio.h>
using namespace std;
class simple
{
 public:
virtual void example()=0;
};
class test: public simple
{
 public:
 void example()
{
 cout<<"C is a Procedural Programming Languages";
}
};
class temp: public simple
{
 public:
 void example()
{
 cout<<"C++ is an Object-Oriented Programming language";
}
};
void main()
{
 Exforsys* arra[2];
 test t1;
 temp t2;
 arr[0]=&t1;
 arr[1]=&t2;
 arr[0]->example();
 arr[1]->example();
 getch();
}

Output:

C is a Procedural Programming Languages
C++ is an Object-Oriented Programming language