Question

#ifndef CCALC_HEADER

#define CCALC_HEADER

  

class   CCalc

{

public:

    // member functions

    CCalc();

    void    Add(double value);

    void    Clear();

    void    Divide(double value);

    double  GetValue() const;

    void    Multiply(double value);

    void    SetValue(double  newValue);

    void    Subtract(double value);

  

private:

    // data members

    double  m_total;

};

  

#endif // CCALC_HEADER

int     main()

{

    CCalc       calculator;

    char        choice;

  

    // loop and let the user manipulate the calculator

    do {

        // display the menu and get the user selection

        DisplayMenu();

        cout << "Please enter a selection: ";

        cin >> choice;

        HandleChoice(calculator, choice);

        cout << endl;

  

        } while ('Q' != toupper(choice));

  

    return 0;

  

} // end of "main"

  

  

  

// ==== DisplayMenu ===========================================================

//

// This function displays the menu of options to stdout.

//

// Input: nothing

//

// Output: nothing

//

// ============================================================================

  

void    DisplayMenu()

{

    cout << "Calculator Options:" << endl;

    cout << " [C] Clear" << endl;

    cout << " [T] Set Value" << endl;

    cout << " [V] Display Value" << endl;

    cout << " [A] Add" << endl;

    cout << " [S] Subtract" << endl;

    cout << " [D] Divide" << endl;

    cout << " [M] Multiply" << endl;

    cout << " [Q] Quit" << endl;

  

} // end of "DisplayMenu"

  

  

  

// ==== HandleChoice ==========================================================

//

// This function handles the menu selection by examining the input char

// parameter and using the CCalc parameter to call the appropriate CCalc member

// function.

//

// Input:

//      calc [IN/OUT]   -- a reference to an existing CCalc object

//

//      item [IN]       -- a char representing the current menu selection

//

// Output:

//      Nothing

//

// ============================================================================

  

void    HandleChoice(CCalc &calc, char item)

{

    double temp;

  

    // switch on the menu selection and call the corresponding CCalc member

    // function

    switch (toupper(item))

        {

        case 'C':

            // clear the calculator so it has a value of zero

            calc.Clear();

            break;

  

     ???

  

  

} // end of "HandleChoice"

Answer 1

// CCalc.h

#ifndef CCALC_HEADER
#define CCALC_HEADER

class CCalc
{

public:

// member functions
CCalc();
void Add(double value);
void Clear();
void Divide(double value);
double GetValue() const;
void Multiply(double value);
void SetValue(double newValue);
void Subtract(double value);

private:

// data members
double m_total;

};

#endif // CCALC_HEADER

//end of CCalc.h

// CCalc.cpp

#include "CCalc.h"

// default constructor to set m_total to 0
CCalc::CCalc() : m_total(0)
{}

// add value to m_total
void CCalc:: Add(double value)
{
m_total += value;
}

// reset m_total to 0
void CCalc:: Clear()
{
m_total = 0;
}

// divide m_total by value
void CCalc:: Divide(double value)
{
m_total /= value;
}

// return m_total
double CCalc:: GetValue() const
{
return m_total;
}

// multiply m_total by value
void CCalc:: Multiply(double value)
{
m_total *= value;
}

// set value to m_total
void CCalc:: SetValue(double newValue)
{
m_total = newValue;
}

// subtract value from m_total
void CCalc:: Subtract(double value)
{
m_total -= value;
}

//end of CCalc.cpp

// main.cpp
#include <iostream>
#include <cctype>
#include "CCalc.h"

using namespace std;

void DisplayMenu();
void HandleChoice(CCalc &calc, char item);

int main()
{
CCalc calculator;
char choice;

// loop and let the user manipulate the calculator
do {

// display the menu and get the user selection
DisplayMenu();
cout << "Please enter a selection: ";
cin >> choice;
HandleChoice(calculator, choice);
cout << endl;
} while ('Q' != toupper(choice));

return 0;
}

// ==== DisplayMenu ===========================================================
//
// This function displays the menu of options to stdout.
//
// Input: nothing
//
// Output: nothing
//
// ============================================================================
void DisplayMenu()
{

cout << "Calculator Options:" << endl;
cout << " [C] Clear" << endl;
cout << " [T] Set Value" << endl;
cout << " [V] Display Value" << endl;
cout << " [A] Add" << endl;
cout << " [S] Subtract" << endl;
cout << " [D] Divide" << endl;
cout << " [M] Multiply" << endl;
cout << " [Q] Quit" << endl;

} // end of "DisplayMenu"

// ==== HandleChoice ==========================================================
//
// This function handles the menu selection by examining the input char
// parameter and using the CCalc parameter to call the appropriate CCalc member
// function.
//
// Input:
// calc [IN/OUT] -- a reference to an existing CCalc object
//
// item [IN] -- a char representing the current menu selection
//
// Output:
// Nothing
//
// ============================================================================
void HandleChoice(CCalc &calc, char item)
{
double temp;

// switch on the menu selection and call the corresponding CCalc member
// function
switch (toupper(item))
{
case 'C':
// clear the calculator so it has a value of zero
calc.Clear();
break;

case 'T':
// input a value
cout<<"Enter a value: ";
cin>>temp;
calc.SetValue(temp); // set calc to temp
break;

case 'V':
// display the current total
cout<<"Value: "<<calc.GetValue()<<endl;
break;

case 'A':
// input a value
cout<<"Enter a value: ";
cin>>temp;
calc.Add(temp); // add temp to calc
break;

case 'S':
// input a value
cout<<"Enter a value: ";
cin>>temp;
calc.Subtract(temp); // subtract temp from calc
break;

case 'D':
// input a value
cout<<"Enter a value: ";
cin>>temp;
// validate input is not 0 as it will cause divide by zero error
// re-prompt until valid
while(temp == 0)
{
cout<<"Divisor cannot be 0. Re-enter: ";
cin>>temp;
}

calc.Divide(temp); // divide calc by temp
break;

case 'M':
// input a value
cout<<"Enter a value: ";
cin>>temp;
calc.Multiply(temp); // multiply calc by temp
break;

case 'Q': // exit
break;

default:
cout<<"Invalid choice"<<endl;
}
} // end of "HandleChoice"

//end of main.cpp

Output: