Question

Write a C++ program which consists of several functions besides the main() function.

1. The main() function, which shall ask for input from the user (ProcessCommand() does this) to compute the following: SumProductDifference and Power. There should be a well designed user interface.
2. A void function called SumProductDifference(int, int, int&, int&, int&), that computes the sum, product, and difference of it two input arguments, and passes the sum, product, and difference by-reference.
3. A value-returning function called Power(int a, int b) that computes a raised to the b power. Design and implement your own power function using an iterative control structure, or even recursion. Do not simply write a wrapper around the C++ function called pow().
4. There should be a user loop and a menu so that the user can select either SumProductDifference, Power, or Quit. Then ProcessCommand() should ask the user for two values to compute SumProductDifference or Power. ProcessCommand() should then also output the answer.

I've got the below one. Can someone help me improve it absolutely as the requirement? I am not good at user loop and menu function. Can you help me add that? And please help me put main function to the top. When I want to put it to the top, the project can't run. I don't know what's the wrong with that.

// ===================
#include <iostream>   
using namespace std;
// ===================

// ==========================================================================
void SumProductDifference(int x, int y, int& sum, int& product, int& diff){
  
sum = x + y;
product = x * y;
diff = x - y;
} // Function SumProductDifference ()
// ====================================
  

// =========================
int power(int a, int b) {

int r = 1;
for (int i = 1; i <= b; i++)
r = r * a;

return r;

} // Function power ()
// ======================

// =====================================
void ProcessCommand(int& x, int& y) {
  
cout << "Enter two numbers :";
cin >> x >> y;

} // Function ProcessCommand()
// ==============================

// ============
int main() {

int x, y, sum, product, diff;
ProcessCommand(x, y);
SumProductDifference(x, y, sum, product, diff);
cout << "Sum = " << sum << "\nProduct= " << product << "\nDifference =" << diff;
cout << "\nPower of " << x << "to " << y << " is :" << power(x, y);

return 0;

} // Function main()
// =====================

Answer 1

Hi,
Please find the answer below:
----------------------------------------------------

To bring the main function to the top, we need to add the function prototypes used in the program
at the top.

//Function prototypes
void SumProductDifference(int , int , int& , int& , int& );
int power(int , int );
void ProcessCommand(int& , int& );

If we dont add the prototypes , we will get errors in the project.

error: 'ProcessCommand' was not declared in this scope|

Fixed C++ Program

// ===================
#include <iostream>
using namespace std;
// ===================

//Function prototypes
void SumProductDifference(int, int, int&, int&, int& );
int power(int, int );
void ProcessCommand(int&, int& );

// Function main()
// =====================
int main()
{
    int x, y, sum, product, diff;
    int selection;

    do
    {
        cout<<"\n\n ------ Program Menu ------"<<endl;
        cout<<"1: SumProductDifference" << endl;
        cout<<"2: Power" << endl;
        cout<<"3: Quit" << endl;
        cout<<"Enter your selection: ";
        cin>>selection;
        if(selection == 1)
        {
            ProcessCommand(x, y);
            SumProductDifference(x, y, sum, product, diff);
            cout << "Sum = " << sum << "\nProduct= " << product << "\nDifference =" << diff;
        }
        else if(selection ==2)
        {
            ProcessCommand(x, y);
            cout << "\nPower of " << x << "to " << y << " is :" << power(x, y);
        }
        else
        {
            //do nothing - Quit option
        }
    }
    while((selection >= 1) && (selection <= 2));

    return 0;
}

// Function SumProductDifference ()
// ==========================================================================
void SumProductDifference(int x, int y, int& sum, int& product, int& diff)
{
    sum = x + y;
    product = x * y;
    diff = x - y;
}

// Function power ()
// =========================
int power(int a, int b)
{
    int r = 1;
    for (int i = 1; i <= b; i++)
        r = r * a;
    return r;
}

// Function ProcessCommand()
// =====================================
void ProcessCommand(int& x, int& y)
{
    cout << "Enter two numbers :";
    cin >> x >> y;
}

Sample Output:

------ Program Menu ------
1: SumProductDifference
2: Power
3: Quit
Enter your selection: 1
Enter two numbers :2 3
Sum = 5
Product= 6
Difference =-1

------ Program Menu ------
1: SumProductDifference
2: Power
3: Quit
Enter your selection: 2
Enter two numbers :3 4

Power of 3to 4 is :81

------ Program Menu ------
1: SumProductDifference
2: Power
3: Quit
Enter your selection: 3

Screenshot

------------------------------------------------------
Hope this helps.
Kindly like the solution if it is useful to you.
Let me know if you need more help.
Thanks.