Microsoft Small Basic

Program Listing: NWT359

List Program

' Monty Hall Problem
' Copyright © 2018 Nonki Takahashi. The MIT License.

GraphicsWindow.Title = "Monty Hall Problem"
Form()
While "True"
nTry = nTry + 1
Shapes.SetText(txt, "Select!")
Select()
Shapes.SetText(txt, "")
OpenBooby()
Shapes.SetText(txt, "Keep or Change?")
KeepOrChange()
If selected2 = prize Then
Shapes.SetText(txt, "YOU WIN!")
Else
Shapes.SetText(txt, "YOU LOSE!")
EndIf
Program.Delay(1000)
NextGame()
EndWhile

Sub AddBehind
n = n + 1
If prize = n Then
behind[n] = Shapes.AddImage(imgCar)
Else
behind[n] = Shapes.AddImage(imgGoat)
EndIf
Shapes.Move(behind[n], x, y)
pos[n] = n
EndSub

Sub AddDoor
n = n + 1
GraphicsWindow.BrushColor = "White"
door[n] = Shapes.AddRectangle(width, height)
Shapes.Move(door[n], x, y)
size = width / 5
GraphicsWindow.BrushColor = "Silver"
knob[n] = Shapes.AddEllipse(size, size)
Shapes.Move(knob[n], x + size * 3.5, y + (height - size) / 2)
EndSub

Sub Change
trial[nTry] = "Changed"
EndSub

Sub CloseDoor
x = Shapes.GetLeft(door[i]) + width / 2
y = Shapes.GetTop(door[i])
For a = 90 To 0 Step -15
_a = Math.GetRadians(a)
scale = Math.Cos(_a)
Shapes.Move(door[i], x + scale * width / 2 - width / 2, y)
k = r * Math.Cos(_a + _b)
Shapes.Move(knob[i], x + k - size / 2, ky)
If 0.1 < scale Then
Shapes.Zoom(door[i], scale, 1)
Program.Delay(delay)
Else
Shapes.ShowShape(door[i])
EndIf
EndFor
EndSub

Sub DumpTrial
If selected2 = prize Then
win[nTry] = "True"
nWin = nWin + 1
Else
win[nTry] = "False"
EndIf
TextWindow.Write("trial[" + nTry + "]=" + trial[nTry] + ";")
TextWindow.Write("win[" + nTry + "]=" + win[nTry] + ";")
TextWindow.WriteLine("percentage=" + Math.Round(nWin / nTry * 100) + "%;")
EndSub

Sub Form
Not = "False=True;True=False;"
TextWindow.Left = 660
TextWindow.Top = 50
gw = 598
gh = 428
GraphicsWindow.Width = gw
GraphicsWindow.Height = gh
GraphicsWindow.Left = 30
GraphicsWindow.Top = 50
GraphicsWindow.BackgroundColor = "LightGray"
folder = Program.Directory + "\"
imgCar = ImageList.LoadImage(folder + "car.png")
imgGoat = ImageList.LoadImage(folder + "goat.png")
height = 200
width = 100
gap = 80
x0 = (gw - width * 3 - gap * 2) / 2
y = (gh - height - 30) / 2 + 30
GraphicsWindow.BrushColor = "Black"
GraphicsWindow.FontSize = 20
GraphicsWindow.FontName = "Trebuchet MS"
txt = Shapes.AddText("")
Shapes.Move(txt, x0, 10)
delta = width + gap
prize = Math.GetRandomNumber(3)
For x = x0 To x0 + delta * 2 Step delta
AddBehind()
EndFor
n = 0
For x = x0 To x0 + delta * 2 Step delta
AddDoor()
EndFor
_b = Math.ArcTan(0.5 / 4)
r = 4 * size / Math.Cos(_b)
GraphicsWindow.PenColor = "Red"
GraphicsWindow.BrushColor = "Transparent"
frame = Shapes.AddRectangle(width, height)
Shapes.HideShape(frame)
delay = 100
GraphicsWindow.MouseDown = OnMouseDown
EndSub

Sub Keep
trial[nTry] = "Kept"
EndSub

Sub KeepOrChange
selected2 = 0
While selected2 = 0
mouseDown = "False"
While Not[mouseDown]
Program.Delay(delay)
EndWhile
For i = 1 To n
If i <> open Then
x1 = Shapes.GetLeft(door[i])
x2 = x1 + width
y1 = Shapes.GetTop(door[i])
y2 = y2 + height
If (x1 <= mx) And (mx <= x2) And (y1 <= my) And (my <= y2) Then
selected2 = i
i = n ' exit For
EndIf
EndIf
EndFor
EndWhile
Shapes.HideShape(frame)
i = selected2
OpenDoor()
If selected = selected2 Then
Keep()
Else
Change()
EndIf
DumpTrial()
EndSub

Sub OnMouseDown
mx = GraphicsWindow.MouseX
my = GraphicsWindow.MouseY
mouseDown = "True"
EndSub

Sub OpenBooby
If selected = prize Then
j = 0
For i = 1 To n
If i <> prize Then
j = j + 1
candidate[j] = i
EndIf
EndFor
open = candidate[Math.GetRandomNumber(2)]
Else
For i = 1 To n
If (i <> prize) And (i <> selected) Then
open = i
i = n ' exit For
EndIf
EndFor
EndIf
i = open
OpenDoor()
EndSub

Sub OpenDoor
x = Shapes.GetLeft(door[i])
y = Shapes.GetTop(door[i])
ky = Shapes.GetTop(knob[i])
For a = 0 To 90 Step 15
_a = Math.GetRadians(a)
scale = Math.Cos(_a)
k = r * Math.Cos(_a + _b)
Shapes.Move(knob[i], x + k - size / 2, ky)
Shapes.Move(door[i], x + scale * width / 2 - width / 2, y)
If 0.1 < scale Then
Shapes.Zoom(door[i], scale, 1)
Else
Shapes.HideShape(door[i])
EndIf
Program.Delay(delay)
EndFor
EndSub

Sub Select
selected = 0
While selected = 0
mouseDown = "False"
While Not[mouseDown]
Program.Delay(200)
EndWhile
For i = 1 To n
x1 = Shapes.GetLeft(door[i])
x2 = x1 + width
y1 = Shapes.GetTop(door[i])
y2 = y2 + height
If (x1 <= mx) And (mx <= x2) And (y1 <= my) And (my <= y2) Then
selected = i
i = n ' exit For
Shapes.Move(frame, x1, y1)
Shapes.ShowShape(frame)
EndIf
EndFor
EndWhile
EndSub

Sub NextGame
i = selected2
CloseDoor()
i = open
CloseDoor()
lastPrize = prize
prize = Math.GetRandomNumber(3)
If prize <> lastPrize Then
i = pos[lastPrize]
j = pos[prize]
Shapes.Move(behind[i], Shapes.GetLeft(door[prize]), Shapes.GetTop(door[prize]))
Shapes.Move(behind[j], Shapes.GetLeft(door[lastPrize]), Shapes.GetTop(door[lastPrize]))
pos[lastPrize] = j
pos[prize] = i
EndIf
EndSub