using System;

namespace Example50
{
	/// <summary>
	/// Summary description for Class1.
	/// </summary>
	class Class1
	{
		public static bool[] door;
		public static Random r = new Random();

		/// <summary>
		/// The main entry point for the application.
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			int TRIALS = 1000;
			door = new bool[4];

			for (int j = 1; j <= 10; j++)
			{
				// Place car behind random door
				door[1] = door[2] = door[3] = false;
				int carBehindDoor = r.Next(1,4);
				door[carBehindDoor] = true;

				int win = 0;
				int lose = 0;

				// Contestant picks a door at random
				for (int i = 1; i <= TRIALS; i++)
				{
					if (door[r.Next(1,4)])
					{
						win++;
					}
					else
					{
						lose++;
					}
				}

				Console.WriteLine("Won {0} times out of {1}; winning percentage={2}",
					win, TRIALS, (1.0 * win) / TRIALS);

				// Contestant picks a random door, Monty opens door with boot prize,
				// contestant switches to other door
				int winSwitch = 0;
				int loseSwitch = 0;

				for (int i = 1; i <= TRIALS; i++)
				{
					int selectedDoor = r.Next(1,4);
					switch (selectedDoor)
					{
						case 1: // contestant selected door 1
							if (door[2]) // Monty opens door 3
								selectedDoor = 2;
							else
							if (door[3]) // Monty opens door 2
								selectedDoor = 3;
							else // Monty opens either 2 or 3
								selectedDoor = 2;
							break;
						case 2: // contestant selected door 2
							if (door[1]) // Monty opens door 3
								selectedDoor = 1;
							else
						    if (door[3]) // Monty opens door 1
								selectedDoor = 3;
							else // Monty either door 1 or 3
								selectedDoor = 1;
							break;
						case 3: // contestant selected door 3
							if (door[1]) // Monty open door 2
								selectedDoor = 1;
							else
							if (door[2]) // Monty open door 1
								selectedDoor = 2;
							else // Monty opens either 1 or 2
								selectedDoor = 1;
							break;
						default:
							Console.WriteLine("CANNOT HAPPEN!");
							break;
					}

					if (door[selectedDoor])
						winSwitch++;
					else
						loseSwitch++;
				}
				
				Console.WriteLine("Won {0} times out {1}; winning percentage={2}",
					winSwitch, TRIALS, (1.0 * winSwitch) / TRIALS);
			}
		}
	}
}