Simulating Monty Hall problem - running X times to get estimation by using Random

MontyHallProblemSimulation.cs

using System;

namespace MontyHallProblemSimulation
{
    public class Program
    {
        private static Random _rnd = null;
        private static char[] _arrDoors;

        private const char DOOR_WITH_CAR = '*';
        private const char DOOR_WITH_GOAT = '-';
        private const int TOTAL_RUNS_EACH_CYCLE = 100000;

        /// <summary>
        /// if value is true, all messages will be displayed.
        /// it will cause a delay when total cycles is larger than 1000
        /// </summary>
        private static bool blnWriteAllToScreen = false;

        private static void WriteLine(string strLine)
        {
            if (blnWriteAllToScreen)
            {
                Console.WriteLine(strLine);
            }
        }

        /// <summary>
        /// this program will simulate Monty Hall issue.
        /// will run TOTAL_RUNS_EACH_CYCLE times
        /// </summary>
        private static void Main(string[] args)
        {
            Console.WriteLine("============== Monty Hall problem simulation ===============");
            Console.WriteLine("===== https://en.wikipedia.org/wiki/Monty_Hall_problem =====");
            Console.WriteLine("Running 2 cycles. each one is " + TOTAL_RUNS_EACH_CYCLE + " tries...");

            _rnd = new Random((int)DateTime.Now.Second);
            int intCountWinsCase1 = 0;

            for (int intRun = 0; intRun < TOTAL_RUNS_EACH_CYCLE; intRun++)
            {
                if (SingleCycle(false))
                {
                    intCountWinsCase1++;
                }
            }

            int intCountWinsCase2 = 0;
            for (int intRun = 0; intRun < TOTAL_RUNS_EACH_CYCLE; intRun++)
            {
                if (SingleCycle(true))
                {
                    intCountWinsCase2++;
                }
            }

            Console.WriteLine(string.Format("When  NOT Changing selection - User is right in {0} out of {1}. in percentage {2:0.00}", intCountWinsCase1, TOTAL_RUNS_EACH_CYCLE, (intCountWinsCase1 / (double)TOTAL_RUNS_EACH_CYCLE) * 100));
            Console.WriteLine(string.Format("When DOES Changing selection - User is right in {0} out of {1}. in percentage {2:0.00}", intCountWinsCase2, TOTAL_RUNS_EACH_CYCLE, (intCountWinsCase2 / (double)TOTAL_RUNS_EACH_CYCLE) * 100));
        }

        private static bool SingleCycle(bool blnChangeDecision)
        {
            _arrDoors = new char[] { DOOR_WITH_GOAT, DOOR_WITH_GOAT, DOOR_WITH_GOAT };

            // put car in random door
            _arrDoors[_rnd.Next(3)] = DOOR_WITH_CAR;

            WriteLine("there are 3 doors. please select door number (1/2/3):");
            WriteLine("Door #");
            int intUserSelection = GetFakeUserSelection();
            WriteLine("\nDoor #" + (int)(intUserSelection+1) + " is selected by user");

            int intEmptyDoor = TellEmptyDoor(intUserSelection);
            WriteLine("Door #" + (int)(intEmptyDoor+1) + " is empty. do you want to change your selection?");

            //var strUserWantTochange = Console.ReadLine();
            //if (strUserWantTochange.ToLower() == "y")
            if (blnChangeDecision)
            {
                // select other door
                for (int intDoorIndex = 0; intDoorIndex < _arrDoors.Length; intDoorIndex++)
                {
                    if (intDoorIndex != intUserSelection && intDoorIndex != intEmptyDoor)
                    {
                        intUserSelection = intDoorIndex;

                        WriteLine("Door #" + (int)(intUserSelection + 1) + " is NEW selection of the user");
                        break;
                    }
                }
            }

            var blnUserIsCorrect = CheckIfUserIsCorrect(intUserSelection);
            if (blnWriteAllToScreen)
            {
                if (blnUserIsCorrect)
                {
                    Console.BackgroundColor = ConsoleColor.Green;
                    Console.ForegroundColor = ConsoleColor.White;
                    WriteLine("User is correct!");
                }
                else
                {
                    Console.BackgroundColor = ConsoleColor.Red;
                    Console.ForegroundColor = ConsoleColor.White;
                    WriteLine("User is wrong");
                }
                Console.ResetColor();
            }

            return blnUserIsCorrect;
        }

        private static bool CheckIfUserIsCorrect(int intUserSelection)
        {
            return (_arrDoors[intUserSelection] == DOOR_WITH_CAR);
        }

        private static int TellEmptyDoor(int intUserSelection)
        {
            // tell user index of a single empty door
            for (int intIndex = 0; intIndex < _arrDoors.Length; intIndex++)
            {
                if (intIndex != intUserSelection && _arrDoors[intIndex] == DOOR_WITH_GOAT)
                {
                    return intIndex;
                }
            }
            return -1;
        }

        private static int GetFakeUserSelection()
        {
            return _rnd.Next(3);
        }

        private static int GetRealUserSelection()
        {
            var strUserInput = Console.ReadLine();
            var intSelection = Convert.ToInt32(strUserInput);
            return intSelection - 1;
        }
    }
}