C++ program to implement virtual function - study materials for competitive exams

/* FIND AREA OF TRIANGLE & RECTANGLE USING VIRTUAL FUNCTION */

#include<iostream.h>

#include<conio.h>

class shape

{

protected:

double x,y;

public:

void get_data(double i,double j=0)

{x=i;

y=j;

}

virtual void set_data(void)

{

cout<<"no area defined\n";

}};

class triangle:public shape

{

public:

void set_data(void)

{

cout<<"triangle with heigth '"<<x<<"' & base '"<<y<<"'\n";

cout<<"has area ="<<x*0.5*y<<"\n";

}};

class rectangle:public shape

{public:

void set_data(void)

{cout<<"\n\nrectangle with length '"<<x<<"' & breadth '"<<y<<"'\n";

cout<<"has area ="<<x*y<<endl;

}};

void main()

{ clrscr();

shape *p;

triangle t;

rectangle r;

p=&t;

p->get_data(10,5);

p->set_data();

p=&r;

p->get_data(5,8);

p->set_data();

getch();

}