Virtual function.

Write a C++ program to illustrate virtual function.

Program Algorithm:

Step 1: Include the header files

Step 2: Declare the base class base.

Step 3: Declare and define the virtual function show().

Step 4: Declare and define the function display().

Step 5: Create the derived class from the base class.

Step 6: Declare and define the functions display() and show().

Step 7: Create the base class object and pointer variable.

Step 8: Call the functions display() and show() using the base class object and pointer.

Step 9: Create the derived class object and call the functions display() and show() using the derived class object and pointer.

Program Code in C++:

#include<iostream.h>

#include<conio.h>

class base

{

public:

virtual void show()

{

cout<<"\n Base class show:";

}

void display()

{

cout<<"\n Base class display:" ;

}

};

class drive:public base

{

public:

void display()

{

cout<<"\n Drive class display:";

}

void show()

{

cout<<"\n Drive class show:";

}

};

void main()

{

clrscr();

base obj1;

base *p;

cout<<"\n\t P points to base:\n" ;

p=&obj1;

p->display();

p->show();

cout<<"\n\n\t P points to drive:\n";

drive obj2;

p=&obj2;

p->display();

p->show();

getch();

}

Program Output:

P points to Base

Base class display

Base class show

P points to Drive

Base class Display

Drive class Show