Write a C++ program to illustrate ‘this’ pointer

Write a C++ program to illustrate ‘this’ pointer and pointers to derived classes.

#include<iostream.h>

#include<conio.h> class BC

{

public: int b;

void show()

{

cout<<"b= "<<b<<endl;

}

BC findlarge(BC obj)

{

if(b>obj.b) return *this;

else

return obj;

}

};

class DC:public BC

{

public: int d;

void show()

{

cout<<"b= "<<b<<endl; cout<<"d= "<<d<<endl;

}

};

int main()

{

clrscr(); BC b1,b2; b1.b=10; b2.b=20;

BC Large=b1.findlarge(b2); cout<<"\n Largest is :"; Large.show();

BC *bptr; BC base; bptr=&base; bptr->b=100;

cout<<"Base pointer to base class\n"; bptr->show();

DC derived; bptr=&derived; bptr->b=200;

cout<<"Base pointer to base class\n";

bptr->show(); DC *dptr; dptr=&derived; dptr->d=300;

cout<<"Derived pointer to derived class\n"; dptr->show();

((DC*)bptr)->d=400; cout<<"Type conversion\n"; ((DC*)bptr)->show(); getch();

return 0;

}

**********************OUTPUT********************************

Largest is :b= 20

Base pointer to base class b= 100

Base pointer to base class b= 200

Derived pointer to derived class b= 200

d= 300

Type conversion b= 200

d= 400