Polymorphism.

Write a C++ program to add and subtract two numbers using polymorphism.

Program Algorithm:

Step 1: Include the header files

Step 2: Declare the base class base

Step 3: Declare and define the function setVar() and getresult()

Step 4: Create a pure virtual function op ()

Step 5: Create two derived classes add and sub from base class

Step 6: Declare the virtual function op ()

Step 7: Create an object pointer for base class

Step 8: Create an object for derived classes and access the member functions to find the result.

Program Code in C++:

#include <iostream.h>

using namespace std;

// abstract base class

class base

{

protected: // attribute section

int num1;

int num2;

int result;

public: // behavior section

void setVar(int n1,int n2)

{

num1 = n1;

num2 = n2;

}

virtual void op() = 0; // pure virtual function

int getresult() 

{

return result;

}

};

class add: public base // add class inherits from base class

{

public:

void op() 

{

result = num1 + num2;

}

};

//sub class inherit base class

class sub: public base

{

public:

void op() 

{

result = num1 - num2;

}

};

int main()

{

int x,y;

base *m; //pointer variable declaration of type base class

add ad; //create object1 for addition process

sub su; //create object2 for subtraction process

cout << "\nEnter two numbers separated by space, or press Ctrl+z to Exit: ";

while(cin >> x >> y)

{

m = &ad;

m->setVar( x , y );

m->op(); //addition process, even though call is on pointer to base!

cout << "\nResult of summation = " << m->getresult();

m = &su;

m->setVar( x , y );

m->op(); //subtraction process, even though call is on pointer to base!

cout << "\nResult of subtraction = " << m->getresult() << endl << endl;

cout << "\nEnter two numbers seperated by space :";

}

return 0;

}

Program Output:

Enter two numbers separated by space: 70 50

Result of summation = 120

Result of subtraction = 20