Someone

int main()
{
int NumShares = 0;
double SalePrice = 0;
double PurchasePrice = 0;
double SaleCom = 0;
double PurchaseCom = 0;
double TradeProfit = 0;
double OverallProfit = 0;
char Again = 'n';

do {
   NumShares = Get_NumShares();
   SalePrice = Get_SalePrice();
   PurchasePrice = Get_PurchasePrice();
   SaleCom = Get_SaleCom();
   PurchaseCom = Get_PurchaseCom();
   TradeProfit = ((NumShares * SalePrice) - SaleCom) - ((NumShares * PurchasePrice) + PurchaseCom);
   OverallProfit += TradeProfit;

   cout << "Wanna try again? (y/n) NOT (Y/N) -> (y/n) :)";
   cin >> Again;
} while(Again == 'y');
}