2016 Update

Task/Monty-Hall-problem/Pascal/monty-hall-problem.pascal

@@ -0,0 +1,50 @@
+program MontyHall;
+
+uses
+  sysutils;
+
+const
+  NumGames = 1000;
+
+
+{Randomly pick a door(a number between 0 and 2}
+function PickDoor(): Integer;
+begin
+  Exit(Trunc(Random * 3));
+end;
+
+var
+  i: Integer;
+  PrizeDoor: Integer;
+  ChosenDoor: Integer;
+  WinsChangingDoors: Integer = 0;
+  WinsNotChangingDoors: Integer = 0;
+begin
+  Randomize;
+  for i := 0 to NumGames - 1 do
+  begin
+    //randomly picks the prize door
+    PrizeDoor := PickDoor;
+    //randomly chooses a door
+    ChosenDoor := PickDoor;
+
+    //if the strategy is not changing doors the only way to win is if the chosen
+    //door is the one with the prize
+    if ChosenDoor = PrizeDoor then
+      Inc(WinsNotChangingDoors);
+
+    //if the strategy is changing doors the only way to win is if we choose one
+    //of the two doors that hasn't the prize, because when we change we change to the prize door.
+    //The opened door doesn't have a prize
+    if ChosenDoor <> PrizeDoor then
+      Inc(WinsChangingDoors);
+  end;
+
+  Writeln('Num of games:' + IntToStr(NumGames));
+  Writeln('Wins not changing doors:' + IntToStr(WinsNotChangingDoors) + ', ' +
+    FloatToStr((WinsNotChangingDoors / NumGames) * 100) + '% of total.');
+
+  Writeln('Wins changing doors:' + IntToStr(WinsChangingDoors) + ', ' +
+    FloatToStr((WinsChangingDoors / NumGames) * 100) + '% of total.');
+
+end.