Question

I almost got my little console-app working, the only problem is that the variable totalComm keeps having the value 0.

I tried everything, I probably just overlooked a small fix which would solve the problem.

Thanks in advance

Philip

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace CommissionCalculator
{
 class Program
  {
    public static void Main()
    {
        double total;
        double comm = 0;
        double totalComm = 0;
        string name = "";

        string inputLetter = "";
        int whilecount = 0;           

        while (inputLetter != "z")
        {
            if (whilecount == 0)
            {
                Title();
                whilecount = whilecount + 1;
            }

            getNameSales(out inputLetter, out name, out total, comm, totalComm);

            calcComm(total, out comm);

            outputVar(name, total, comm);

            totalCommCalc(comm, totalComm);
        }
    }

    public static void Title()
    {
        Console.WriteLine("\n           Sunshine Hot Tubs \n        Sales Commissions Report\n");
    }

    public static void getNameSales(out string inputLetter, out string name, out double total, double comm, double totalComm)
    {
        name = "";
        inputLetter = "";
        total = 0;

        Console.WriteLine("\nEnter salespersons initial a,b or e or enter z to quit");

        inputLetter = Console.ReadLine();

            if (inputLetter == "a")
            {
                name = "Andrea";

                string inValue;
                double sale = 0;
                total = 0;

                for (int count = 1; count <= 3; ++count)
                {
                    Console.WriteLine("Please enter sale: ");
                    inValue = Console.ReadLine();
                    sale = Convert.ToDouble(inValue);

                    total = total + sale;
                }
            }
            else if (inputLetter == "b")
            {
                name = "Brittany";

                string inValue;
                double sale = 0;
                total = 0;

                for (int count = 1; count <= 3; ++count)
                {
                    Console.WriteLine("Please enter sale: ");
                    inValue = Console.ReadLine();
                    sale = Convert.ToDouble(inValue);

                    total = total + sale;
                }
            }
            else if (inputLetter == "e")
            {
                name = "Eric";

                string inValue;
                double sale = 0;
                total = 0;

                for (int count = 1; count <= 3; ++count)
                {
                    Console.WriteLine("Please enter sale: ");
                    inValue = Console.ReadLine();
                    sale = Convert.ToDouble(inValue);

                    total = total + sale;
                }
            }
            else if (inputLetter == "z")
            {
                totalCommCalc(comm, totalComm);

                Console.WriteLine("Total commssion paid: {0:C}", totalComm);

                Console.ReadKey();
            }
        }

    public static void calcComm(double total, out double comm)
    {
        comm = total * 0.2;
    }

    public static double totalCommCalc(double comm, double totalComm)
    {            
        totalComm = totalComm + comm;

        return totalComm;
    }

    public static void outputVar(string name, double total, double comm)        
    { 
        Console.WriteLine("\n Name\t       Total sales\t     Commission \n{0}     \t    {1}     \t      {2}", name, total, comm);            
    }
  }
}

Answer 1

totalComm is passed by value to totalCommCalc. Either pass it by reference, or return it from totalCommCalc and assign back to totalComm.

When a variable is passed by value, a copy is placed on the stack of the method you call. Changes to that copy do not affect the original.

When you pass by reference, the address of the original is placed on the stack, and changes do affect the original.

Option 1:

// Passed by reference.
// Changes affect original.  
// Has side effects.  See http://en.wikipedia.org/wiki/Side_effect_%28computer_science%29
totalCommCalc(comm, ref totalComm);  

Option 2:

// Preferred.  Passed by value.  
// Result is assigned to a variable.  
// No side effects.
totalComm = totalCommCalc(comm, totalComm); 

I would prefer the second form, as code that has side effects can be harder to understand and maintain as it grows.