C# how to include 0 in Roulette Simulation?

Question

So I want to simulate a roulette to proof that the House always wins.

I’m almost done but I stumbled upon a problem. I’m able to enter how many times to roll and it works fine. I get different numbers and it also tells me if red or black.

However the number 0 won’t show up in the results. I don’t know how to fix this, the code looks fine to me.

Code:

namespace ConsoleApplication9
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] Null = new int[1] { 0 };
            int[] Rote = new int[18] { 1, 3, 5, 7, 9, 12, 14, 16, 18, 19, 21, 23, 25, 27, 30, 32, 34, 36 };
            int[] Schwarze = new int[18] { 2, 4, 6, 8, 10, 11, 13, 15, 17, 20, 22, 24, 26, 28, 29, 31, 33, 35 };

        // 0 ohne Tischlimit

        var list = new List<int>();
        list.AddRange(Rote);
        list.AddRange(Schwarze);
        list.AddRange(Null);

        Console.WriteLine("Wie oft soll gespielt werden?");
        int Anzahl = Convert.ToInt32(Console.ReadLine());
        Random zufall = new Random();

        for (int i = 0; i < Anzahl; ++i)
        {
            int number = list[zufall.Next(0, list.Count - 1)];

            if (Rote.Contains(number))
            {
                Console.WriteLine("Rot" + number);
            }

            if (Schwarze.Contains(number))
            {
                Console.WriteLine("Schwarz" + number);
            }

            if (Null.Contains(number))
            {
                Console.WriteLine("Null" + number);
            }
        }
        Console.ReadLine();
    }
}

Answer 1

Ok, the thing is that Random.Next Method (Int32, Int32) uses upper bound as exclusive. So you have 0 as last element of list. And passing list.Count - 1 results in generating values between 0 and list.Count - 2. So the last element of the list is just ignored as you will never generate the last index list.Count - 1. You need to pass list.Count to Next method:

int number = list[zufall.Next(0, list.Count)];

https://msdn.microsoft.com/en-us/library/2dx6wyd4(v=vs.110).aspx

The Next(Int32, Int32) overload returns random integers that range from minValue to maxValue – 1