Question

// P13_2.cpp - This program adds money of two different people
#include<iostream>
#include<cstdlib>
using namespace std;

class AltMoney
{
    public:
        AltMoney();
        AltMoney(int d, int c);

        friend void add(AltMoney m1, AltMoney m2, AltMoney& sum);
        void display_money( );
    private:
        int dollars;
        int cents;
};

void read_money(int& d, int& c);

int main( )
{
     int d, c;
     AltMoney m1, m2, sum;

     sum = AltMoney(0,0);

     read_money(d, c);
     m1 = AltMoney(d,c);
     cout << "The first money is:";
     m1.display_money();

     read_money(d, c);
     m2 = AltMoney(d,c);
     cout << "The second money is:";
     m2.display_money();

     add(m1,m2, sum);
     cout << "The sum is:";
     sum.display_money();

     return 0;
}

AltMoney::AltMoney()
{
}

AltMoney::AltMoney(int d, int c)
{
       dollars = d;
       cents = c;
}

void AltMoney::display_money()
{
     cout << "$" << dollars << ".";
     if(cents <= 9)
         cout << "0"; //to display a 0 in the left for numbers less than 10
     cout << cents << endl;
}

void add(AltMoney m1, AltMoney m2, AltMoney& sum)
{
     int extra = 0;
     sum.cents = m1.cents + m2.cents;
     if(sum.cents >=100){
         sum.cents = sum.cents - 100;
         extra = 1;
      }
      sum.dollars = m1.dollars + m2.dollars + extra;
}

void read_money(int& d, int& c)
{
     cout << "Enter dollar \n";
     cin >> d;
     cout << "Enter cents \n";
     cin >> c;
     if( d < 0 || c < 0)
     {
            cout << "Invalid dollars and cents, negative values\n";
            exit(1);
      }
}

In this program the function add is no longer a member function, but it is a friend to the class AltMoney and has access to private variable members. In general, we may want to include the function that does the reading of variables as a function member or make it a friend so that it reads the dollars and cents and directly assigns them to the dollars and cents of an object.

Exercise 13.2

Modify the above C++ program to include the following changes. Call your new program ex13_2.cpp.

1. Modify the previous add function so that it becomes now a member function of the class AltMoney. The function takes the sum of dollars and cents of an object AltMoney and returns the result as an AltMoney. Note that in the above version of the program, the object sum has been passed by reference. Do not pass the sum any longer.

2. Add a new friend function, called subtract, that computes the subtraction of one money from another.

3. Modify read_money and make it member function of AltMoney. Note that if you make read_money a member function, then you can use it to directly initialize the dollars and cents of an AltMoney type object directly.

4. Modify the main to reflect that above changes and the program is still functional, and add a call to subtract to test that the function subtract works properly

Answer 1

****This requires some effort so please drop a like if you are satisfied with the solution****

I have satisfied all the requires changes as per the question and I'm providing the screenshots of code and output for your reference...

Code:

#include<iostream>
#include<cstdlib>
using namespace std;

class AltMoney
{
public:
AltMoney();
AltMoney(int d, int c);

AltMoney add(AltMoney m1, AltMoney m2);
void read_money(AltMoney& obj);
friend void subtract(AltMoney m1, AltMoney m2, AltMoney& sub);
void display_money( );
private:
int dollars;
int cents;
};

void read_money(int& d, int& c);

int main( )
{
AltMoney m1, m2, sum,sub;

sum = AltMoney(0,0);

m1.read_money(m1);
cout << "The first money is:";
m1.display_money();

m2.read_money(m2);
cout << "The second money is:";
m2.display_money();

sum=sum.add(m1,m2);
cout << "The sum is:";
sum.display_money();
subtract(m1,m2,sub);
cout<<"The subtraction is:";
sub.display_money();

return 0;
}

AltMoney::AltMoney()
{
}

AltMoney::AltMoney(int d, int c)
{
dollars = d;
cents = c;
}

void AltMoney::display_money()
{
cout << "$" << dollars << ".";
if(cents <= 9)
cout << "0"; //to display a 0 in the left for numbers less than 10
cout << cents << endl;
}

AltMoney AltMoney::add(AltMoney m1, AltMoney m2)
{
int extra = 0;
AltMoney sum;
sum.cents = m1.cents + m2.cents;
if(sum.cents >=100){
sum.cents = sum.cents - 100;
extra = 1;
}
sum.dollars = m1.dollars + m2.dollars + extra;
return sum;
}
void subtract(AltMoney m1, AltMoney m2, AltMoney& sub)
{
int extra = 0;
sub.cents = m1.cents - m2.cents;
if(sub.cents <0){
sub.cents = 100+sub.cents;
extra = 1;
}
sub.dollars = m1.dollars - m2.dollars - extra;
}

void AltMoney::read_money(AltMoney& obj)
{
   cout << "Enter dollar \n";
cin >> obj.dollars;
cout << "Enter cents \n";
cin >> obj.cents;
if( obj.dollars < 0 || obj.cents < 0)
{
cout << "Invalid dollars and cents, negative values\n";
exit(1);
}
}

Output Screenshot:

Code Screenshots: