Monte Hall

using System;

namespace MontyHall
{
    class Puzzle
    {
        private bool[] doors;

        public int[] unchosen (int choice)
        {
            int[] u = new int[2];
            for (int i = 0, iu = 0; i < 3; ++i) {
                if (choice != i)
                    u [iu++] = i;
            }
            //Console.WriteLine ("\t <<unchosen returning {0} and {1}>>", u [0], u [1]);
            return u;
        }

        public int unchosen_loser(Random r, int choice)
        {
            int[] unch = unchosen (choice);
            int rand = r.Next (2);
            if (doors [unch [rand]] != true)
                return unch [rand];
            else
            {
                if (rand == 0)
                    return unch[1];
                else
                    return unch[0];
            }
        }

        public bool reveal(int choice)
        {
            return doors [choice];
        }

        public Puzzle(Random r)
        {
            doors = new bool[3];
            doors [r.Next (3)] = true;
        }

    }

    class MainClass
    {

        public static void Main (string[] args)
        {
            int iterations = 10000000;
            int choice;
            int successes = 0;
            int failures = 0;

            Random r = new Random();

            if (args.Length != 0)
                int.TryParse (args [0], out iterations);

            Console.WriteLine ("Testing Monte Hall problem {0} times...", iterations);

            r = new Random ();

            for (int i = 0; i < iterations; ++i)
            {
                Puzzle p = new Puzzle (r);
                choice = r.Next (3);
                int[] unch = p.unchosen (choice);
                int loser = p.unchosen_loser (r, choice);
                //int newchoice;

                //Console.WriteLine ("New puzzle!" + Environment.NewLine + "Choosing: {0}", choice + 1);
                //Console.WriteLine ("\t << Unchosen doors are {0} and {1}. >>", unch [0] + 1, unch [1] + 1);
                //Console.WriteLine ("Door {0} has been opened!", loser + 1);

                //Change this below to alter strategy

                if (unch [0] == loser)
                    choice = unch [1];
                else
                    choice = unch [0];

                //Console.WriteLine ("Changing choice to {0}.", choice + 1);

                if (p.reveal (choice) == true) {
                    //Console.WriteLine ("You win!");
                    ++successes;
                } else {
                    //Console.WriteLine ("You lose.");
                    ++failures;
                }
                for (int iw = 0; iw < 3; ++iw) {
                    if (p.reveal (iw)) {
                        //Console.WriteLine ("<< Winning door is {0}. >> ", iw + 1);
                    }
                }
                //Console.WriteLine ();
            }

            Console.WriteLine ("Out of {0} games, you have won {1} ({2}%).", iterations, successes, ((double)successes / (double)iterations) * 100);
        }
    }
}