Monty Hall Simulation - Printable Version

Code: (Select All)

_Title "Monty Hall Simulator" ' dcromley

Option _Explicit

Dim s$, pause$, n

Dim Shared carDoor, choiceDoor, openDoor, offerDoor

Dim stickerWins, stickerLosses, switcherWins, switcherLosses

Randomize Timer

Locate 2, 6: Print " '1' for single trial; '2' for continuous running; ESC to exit"

pause$ = "1"

Do

  n = n + 1

  Locate 4, 2: Print "Trial#";: Print Using "#,###,###,###"; n

  ' get setup for this n

  carDoor = 1 + Int(Rnd * 3) ' the car, 1-3

  choiceDoor = 1 + Int(Rnd * 3) ' the choice,1-3

  openDoor = getopenDoor ' host opens a non-car Door

  offerDoor = getofferDoor ' the offer is not the choiceDoor, not the openDoor

  Locate , 2: Print "carDoor="; carDoor

  Locate , 2: Print "choiceDoor="; choiceDoor

  Locate , 2: Print "openDoor="; openDoor

  Locate , 2: Print "offerDoor="; offerDoor

  ' -- the sticker (non-switcher) --

  If choiceDoor = carDoor Then stickerWins = stickerWins + 1 Else stickerLosses = stickerLosses + 1

  ' -- the switcher --

  If offerDoor = carDoor Then switcherWins = switcherWins + 1 Else switcherLosses = switcherLosses + 1

  ' post results

  Locate , 2

  print using "Non-Switcher: Wins=#,###,###,### Losses=#,###,###,### Percent=###.###"; _

    stickerWins;stickerLosses;100*stickerWIns/n

  Locate , 2

  print using "Switcher:     Wins=#,###,###,### Losses=#,###,###,### Percent=###.###"; _

    switcherWins;switcherLosses;100*switcherWIns/n

  If pause$ = "1" Then

    Do

      pause$ = InKey$

    Loop While pause$ = ""

  Else

    pause$ = InKey$

  End If

Loop Until pause$ = Chr$(27)



Function getopenDoor () ' open a non-car door

  Dim r

  Do

    r = 1 + Int(Rnd * 3)

  Loop Until r <> choiceDoor And r <> carDoor

  getopenDoor = r

End Function



Function getofferDoor () ' offer the non-open door

  Dim r

  Do

    r = 1 + Int(Rnd * 3)

  Loop Until r <> choiceDoor And r <> openDoor

  getofferDoor = r

End Function

Code: (Select All)

Option _Explicit

Dim As Long trials, t, i, grandPrize, pick1, doorOpen, doorSwitch, OnePicker, Switcher

trials = 100

For t = 1 To trials

    grandPrize = Int(Rnd * 3) + 1 ' door 1 to 3

    pick1 = Int(Rnd * 3) + 1

    For i = 1 To 3

        If i <> grandPrize And i <> pick1 Then doorOpen = i: Exit For

    Next

    For i = 1 To 3 ' find doorSwitch

        If i <> pick1 And i <> doorOpen Then doorSwitch = i: Exit For

    Next

    If grandPrize = pick1 Then OnePicker = OnePicker + 1

    If grandPrize = doorSwitch Then Switcher = Switcher + 1

Next

Print "One picker wins ="; OnePicker

Print "Switcher wins = "; Switcher

Code: (Select All)

Dim door(1 To 3)

Const Limit = 1000 'number of games to play without switching, and then repeat that number and switch

Randomize Timer





For i = 1 To Limit

    Print "Game #"; i

    prize = Int(Rnd * 3) + 1 'which door is the prize behind?

    Print "Is it behind Door #1, #2, or #3?"

    guess = Int(Rnd * 3) + 1 'where is our initial guess

    Print "I guess door #"; guess

    'here we can waste some time not swapping

    If guess = prize Then eliminate = guess + 1: If eliminate > 3 Then eliminate = 1



    Print "It's not behind door #"; eliminate; "!  Will you swap?"

    Print "Nope!  I want to keep my choice."

    Print "Since you're keeping it, let's see what happens!"

    If guess = prize Then

        win = win + 1

        Print "You win the car!"

    Else

        lose = lose + 1

        Print "Sorry!  It was behind door #"; prize

    End If

Next



Print "Of "; Limit; "games, you won "; win; "times and lost "; lose; "times by not swapping!"

Sleep





For i = 1 To Limit

    Print "Game #"; i

    prize = Int(Rnd * 3) + 1 'which door is the prize behind?

    Print "Is it behind Door #1, #2, or #3?"

    guess = Int(Rnd * 3) + 1 'where is our initial guess

    Print "I guess door #"; guess

    'here we can waste some time not swapping

    If guess = prize Then eliminate = guess + 1: If eliminate > 3 Then eliminate = 1



    Print "It's not behind door #"; eliminate; "!  Will you swap?"

    Print "Nope!  I want to keep my choice."

    Print "Since you're keeping it, let's see what happens!"

    If guess = prize Then

        lose2 = lose2 + 1

        Print "Sorry!  It was behind door #"; eliminate

    Else

        win2 = win2 + 1

        Print "You win the car!"



    End If

Next



Print "Of "; Limit; "games, you won "; win2; "times and lost "; lose2; "times by swapping!"

Print

Print "To compare:"

Print "Of "; Limit; "games, you won "; win; "times and lost "; lose; "times by not swapping!"