A C++ program to design a calculator using class.

#include <iostream>

#include <iomanip>

#include <cmath>

using namespace std;

class calc

{

            double newEntry;

            double displayedVal;

public:

double doDivideZero(double &)

{

            newEntry =0;

            displayedVal = 0.0;

           

            if (newEntry !=0)

            {

                        displayedVal = displayedVal / newEntry;

            } else cout << "Wrong Operation, Cannot Divide by Zero" << endl;

           

                       

                       

           

            return 0;          

}

};

Void  main()

{

           

           

            double displayedVal;

            double newEntry;

            char command_character ;

           

            displayedVal = 0.0;

            calc c;

            cout << "  Enter accepted Operator:" ;

            cin >> command_character;

            while (command_character != 'Q' || command_character != 'q')

            {

                        switch(command_character)

                        {

                        case 'c':

                        case 'C': displayedVal = 0.0;

                                                  break;

                        case '+': cout << "  Enter Number:";

                                                  cin >> newEntry;

                                                  displayedVal = displayedVal + newEntry;

                                                  break;

                        case '-': cout << "  Enter Number:";

                                                  cin >> newEntry;

                                                  displayedVal = displayedVal - newEntry;

                                                  break;

                        case '*': cout << "  Enter Number:";

                                                  cin >> newEntry;

                                                  displayedVal = displayedVal * newEntry;

                                                  break;

                        case '/': cout << "  Enter Number:";

                                          cin >> newEntry;

                                                  displayedVal = displayedVal / newEntry;

                                                  if (newEntry == 0)

                                                  {

                                                              c.doDivideZero(double &);

                                                  }

                                                 

                                                  break;

                        case '^': cout << "  Enter Number:";

                                                  cin >> newEntry;

                                                  displayedVal = pow (displayedVal,newEntry);

                                                  break;

                                                  default : cout << "  Unacceptable Operator(" << command_character << ")" << endl;

                        }

                        cout << "  The result so far is: " <<displayedVal<< endl;

                        cout << "  Enter Operator:";

                        cin >> command_character;

                       

                       

            }

Getch();

}