#!/usr/bin/perl

#--------------------------------------------------------------------------------
# Monty Hall Trap
#--------------------------------------------------------------------------------


$Number_of_games_to_play    =   100; # Set to any number of games.

$Doors                      =   3;   # Total number of doors on the set

$Reveal                     =   -1;  # >0 means to reveal that number or doors
                                     # <0 means to reveal $Doors+$Reveal-1
                                     #    (or just leave you with 
                                     #     one door to swap to)

$Verbose                    =   1;   # Print the results for each game

$Swap_Option                =   1;   # -1 Never swap
                                     #  0 Sometimes swap
                                     #  1 Always swap doors


#--------------------------------------------------------------------------------
# The following code plays the game and there is no need to change anything.
#--------------------------------------------------------------------------------

# Set the reveal if its 0 or a negative number
if ($Reveal < 1) {
    $Reveal = $Doors + $Reveal - 1;
}

die ("Reveal was too high.") if $Reveal >= ($Doors - 1);

$Game_Number    = 1;
$Correct        = 0;
$Swapped        = 0;

for $Game_Number ( 1 .. $Number_of_games_to_play ) {
    #Seed the doors:
    @Door_Flags = ();
    for (1..$Doors) { push(@Door_Flags,' ') }

    $This_Games_Correct_Door = int(rand($Doors)+1);
    $Door_Flags[$This_Games_Correct_Door] = 'W';
    print "Game $Game_Number: Door $This_Games_Correct_Door\n" if $Verbose;
    
    $This_Games_Guess = int(rand($Doors)+1);
    $Door_Flags[$This_Games_Guess] = 'G';
    print "Game $Game_Number: Guess $This_Games_Guess\n" if $Verbose;

    for $r ( 1 .. $Reveal ) {
        $Game_Reveal = int(rand($Doors)+1);
        $break=0;
        while (($Door_Flags[$Game_Reveal]=~/\w/) &amp;&amp; ($break < 10000)) { $break++;
            $Game_Reveal = int(rand($Doors)+1);
        }
        last if ($break >= 10000);
        $Door_Flags[$Game_Reveal] = 'R';
        print "Game $Game_Number: Reveal $Game_Reveal\n" if $Verbose;
    }
    
    $Swap = ($Swap_Option) ? $Swap_Option+1 : int(rand(2));
    if ($Swap) {
        $s=0;
        do {$s++} until (($Door_Flags[$s] ne 'R') &amp;&amp; ($s != $This_Games_Guess));
        $This_Games_Guess = $s;
        $Swapped++;
        print "Game $Game_Number: Changed my guess to $This_Games_Guess\n" if $Verbose;
    }
    
    if ($This_Games_Guess == $This_Games_Correct_Door) {
        print "YOU WIN!\n" if $Verbose;
        $Correct++;
    } else {
        print "You lose.\n" if $Verbose;
    }
    
    print "Doors: " . join('|',@Door_Flags) . "|\n" if $Verbose;

    print "\n" if $Verbose;
}

print "I played $Number_of_games_to_play games and won $Correct. I swapped my guess on $Swapped games.";