C# How to calculate total for each payment method

Question

Can you please help me calculate the total of each payment type such as visa, mastercard and paypal. I have created interface IPay and inherited from it in Mastercard, Visa and PayPal class. It displays each customer details along with number of orders and payment type. I need to calculate Total Payment for each payment type. Thanks.

public class Program
{
 public static void Main()
 {
    Customer[] custArray = new Customer[3];

    // First Customer
    custArray[0] = new Customer() { FirstName = "Adam", LastName = "Miles", Orders = new Order[2] };
    custArray[0].Orders[0] = new Order() { Description = "Shoes", Price = 19.99M, Quantity = 1, Pay = new MasterCard() };
    custArray[0].Orders[1] = new Order() { Description = "Gloves", Price = 29.99M, Quantity = 2,Pay = new Visa() };

    // Second Customer
    custArray[1] = new Customer() { FirstName = "Andrew", LastName = "Hart", Orders = new Order[2] };
    custArray[1].Orders[0] = new Order() { Description = "Jacket", Price = 39.99M, Quantity = 1,Pay = new MasterCard() };
    custArray[1].Orders[1] = new Order() { Description = "Socks", Price = 49.99M, Quantity = 1,Pay = new Paypal() };


    foreach (var customer in custArray)
    {
        if (customer == null) continue;

        Console.WriteLine("Customer:\n");
        Console.WriteLine("{0, 15} {1, 17}", "First Name", "Last Name");
        Console.WriteLine("{0, 10} {1, 20}", customer.FirstName, customer.LastName);
        Console.WriteLine("Orders:\n");

        foreach (var order in customer.Orders)
        {
            if (order == null) continue;

            Console.WriteLine("{0, 10} {1, 10} {2, 10}{3, 15}", order.Description, order.Price, order.Quantity, order.Pay);
            Console.WriteLine("\n\n");
            decimal total = order.Price * order.Quantity;
            Console.WriteLine("Total :", total);

            if (order.Pay== new MasterCard())
            {
                total = total++;   
                Console.WriteLine("Visa Total", total);
            }

            else if (order.Pay == new Visa())
            {
                total = total++;
                Console.WriteLine("Visa Total", total);
            }

            else if (order.Pay == new MasterCard())
            {
                total = total++;
                Console.WriteLine("Visa Total", total);
            }

        }
        Console.WriteLine("\n\n");


    }



        Console.ReadLine();
    }
}

class Customer
{
    public string FirstName;
    public string LastName;
    public Order[] Orders;


}
class Order
{
    public string Description;
    public decimal Price;
    public int Quantity;
    public IPay Pay; 
    // Payment type p=new pay

}
interface IPay
{
    void PayType();
}

class MasterCard : IPay
{
    public void PayType { get; set; }
}

    class Paypal : IPay
    {
        public void PayType { get; set; }
    }
    public class Visa : IPay
    {
        public void PayType {get;set;}

    }        

Answer 1

As Yorye stated in the comments, you might rethink your design.

Following linq query gives what you need.

    var res = custArray.Where(c => c != null).SelectMany(c => c.Orders)
        .GroupBy(c => c.Pay.GetType().ToString())
        .Select(c => new { PayType = c.Key, Sum = c.Sum(a => a.Price * a.Quantity) });

    foreach (var re in res)
    {
        Console.WriteLine("CardType {0}, Total : {1}", re.PayType.ToString(), re.Sum);
    }

Since you are a bignner it might take a while to understand some of these advanced concepts.

As an alternative you can refer below code.

var results = new Dictionary<string, decimal>();

foreach (var order in customer.Orders)
{
    string key = order.Pay.GetType().ToString();
    if (!results.ContainsKey(key))
    {
        results.Add(key,(decimal) 0.0);
    }

    results[key] += results[key] + order.Quantity*order.Price;
}

Answer 2

You really have a lot to learn, judging from your code, learn about scope, syntax, overloaded methods of the Console.Writeline() method and that should get you on your way for this assignment, I have fixed your code a little already. Using an enum (google it) to differentiate between payment types... Inside your main method:

        static void Main(string[] args)
    {
        Customer[] custArray = new Customer[3];

        // First Customer
        custArray[0] = new Customer() { FirstName = "Adam", LastName = "Miles", Orders = new Order[2] };
        custArray[0].Orders[0] = new Order() { Description = "Shoes", Price = 19.99M, Quantity = 1, PayType = PayType.MasterCard };
        custArray[0].Orders[1] = new Order() { Description = "Gloves", Price = 29.99M, Quantity = 2, PayType = PayType.Visa };

        // Second Customer
        custArray[1] = new Customer() { FirstName = "Andrew", LastName = "Hart", Orders = new Order[2] };
        custArray[1].Orders[0] = new Order() { Description = "Jacket", Price = 39.99M, Quantity = 1, PayType = PayType.MasterCard };
        custArray[1].Orders[1] = new Order() { Description = "Socks", Price = 49.99M, Quantity = 1, PayType = PayType.Visa };

        decimal total = 0;
        decimal totalMaster = 0;
        decimal totalVisa = 0;
        decimal totalPaypal = 0;

        foreach (var customer in custArray)
        {
            if (customer == null) continue;

            Console.WriteLine("Customer:\n");
            Console.WriteLine("{0, 15} {1, 17}", "First Name", "Last Name");
            Console.WriteLine("{0, 11} {1, 16}", customer.FirstName, customer.LastName);
            Console.WriteLine("Orders:\n");

            decimal cust_total = 0;
            decimal cust_totalMaster = 0;
            decimal cust_totalVisa = 0;
            decimal cust_totalPaypal = 0;

            foreach (var order in customer.Orders)
            {
                if (order == null) continue;

                Console.WriteLine("{0, 10} {1, 10} {2, 10}{3, 15}", order.Description, order.Price, order.Quantity, order.PayType);
                Console.WriteLine("\n\n");

                total += order.Price * order.Quantity;
                cust_total += order.Price * order.Quantity;

                if (order.PayType == PayType.MasterCard)
                {
                    totalMaster += order.Price * order.Quantity;
                    cust_totalMaster += order.Price * order.Quantity;
                }

                else if (order.PayType == PayType.Visa)
                {
                    totalVisa += order.Price * order.Quantity;
                    cust_totalVisa += order.Price * order.Quantity;
                }

                else if (order.PayType == PayType.Paypal)
                {
                    totalPaypal += order.Price * order.Quantity;
                    cust_totalPaypal += order.Price * order.Quantity;
                }
            }
            Console.WriteLine("MasterCard Total: {0, 8}", cust_totalMaster);
            Console.WriteLine("Visa Total: {0, 13}", cust_totalVisa);
            Console.WriteLine("Paypal Total: {0, 8}", cust_totalPaypal);
            Console.WriteLine("Total: {0, 18}", cust_total);
        }
        Console.WriteLine("\n\n");
        Console.WriteLine("MasterCard GrandTotal: {0, 10}", totalMaster);
        Console.WriteLine("Visa GrandTotal: {0, 13}", totalVisa);
        Console.WriteLine("Paypal GrandTotal: {0, 10}", totalPaypal);
        Console.WriteLine("GrandTotal: {0, 18}", total);

        Console.ReadLine();
    }

Classes:

class Customer
{
    public string FirstName;
    public string LastName;
    public Order[] Orders;

}
class Order
{
    public string Description;
    public decimal Price;
    public int Quantity;
    public PayType PayType { get; set; }
    //public IPay Pay;
    // Payment type p=new pay

}

enum PayType{

    MasterCard,
    Visa,
    Paypal
}

I would strongly recommend baby steps, that is why I changed your structure a bit so you can hopefully understand certain concepts better, alter the code slightly to learn the basics of the language and programming better before diving in too deep - It will be overwhelming.

You just need to fix the tab formatting...