C++ Adding sum of multiple function calls within a loop - c++

Question

I've been working on an assignment that calculates the total profit/loss for multiple stock sales via a looping function with information inputted by user for each stock sale. I did a thorough amount of googling to no avail. I was able to get the function working within the loop but I have not been able to figure out how to add the profit/loss from multiple sales - instead only displaying profit/loss for each individual function call. My function's algorithm checks out if you manually add the totals for each sale, just unclear on how to find the sum of multiple function calls.
Here is the sample data I'm suppose to enter that should display the total profit of $3324.00:
sale numberOfShares salePrice salesCommission purchasePrice purchaseCommission
1 25 15 7.50 5 2.50
2 100 2.50 12 1.75 8
3 1000 5.10 51 2 20
And my code thus far:
#include <iostream>
#include <iomanip>
using namespace std;
// Function prototype
double stockProfitFunction(double NS, double PP, double PC, double SP, double SC);
// Main Function
int main()
{
// Format output
cout << fixed << setprecision(2);
// Initialize variables
double profit,
numberOfShares,
salePrice,
saleCommission,
purchasePrice,
purchaseComission;
int numberOfSales;
// Get # of sales from user
cout << "Multiple Stock Profit Calculator\n--------------------------------\n\n";
cout << "How many sales do you wish to enter?: ";
cin >> numberOfSales;
cout << endl;
// Perform function in loop for number of sales
for (int i = 1; i <= numberOfSales; i++)
{
system("cls"); // Clears screen
cout << "Multiple Stock Profit Calculator\n";
cout << "(Currently entering stock sale #" << i << ")\n----------------------------------\n";
// Get information from user
cout << "Enter number of shares: ";
cin >> numberOfShares;
cout << "Enter sale price: ";
cin >> salePrice;
cout << "Enter sales commission: ";
cin >> saleCommission;
cout << "Enter purchase price: ";
cin >> purchasePrice;
cout << "Enter purchase commission: ";
cin >> purchaseComission;
//Calcualtes profit with function
profit = stockProfitFunction(numberOfShares, purchasePrice, purchaseComission, salePrice, saleCommission);
// Display "profit" or "loss" depending on positive or negative value returned by function
if (profit >= 0)
{
cout << "\n-----------------------\n";
cout << "You earned a profit of: $" << profit << endl;
cout << "(Press enter to input next sale)";
cin.get();
cin.get();
}
else
{
cout << "\n-----------------------\n";
cout << "You had a loss of: $" << profit << endl;
cout << "(Press enter to input next sale)";
cin.get();
cin.get();
}
}
return 0;
}
// Stock Profit Function, returns profit
double stockProfitFunction(double NS, double PP, double PC, double SP, double SC)
{
return ((NS * SP) - SC) - ((NS * PP) + PC);
}
Thanks for taking a look!

Answer 1

Initialize a variable to zero.
Each time you calculate a profit, add it to that variable.
Where desired, output the value of that variable.
By the way:
system("cls"); // Clears screen
That's a very bad habit to get into. Maybe on your machine, cls clears the screen, but you have no way to know what the cls command might do on someone else's machine. (On mine, there is no command called cls, the clear screen command is clear.) Unless you absolutely have no choice, you should strongly avoid using system in your C++ code.