Any way to trim all these IF statements?

Any way to trim all these IF statements?

• khandar

  Another take on this:  rather than checking all of these locations at the end, you could simply track the changes as they happen as bits in a UShort.  You presumably are handling some event which “moves” the buttons.  You can detect then and there if a given square is in the right stop and, if so, set an appropriate value (or clear it, if it is not in the right place).  SO for example, in your fourth button:

  If B4.Top = 28 Then
   Me.TrackingUShort = TrackingUShort Or 1 << 3  ‘  Shift this three spaces to be in the "4" spot
  Else
   Me.TrackingUShort = TrackingUShort And Not 1 << 3
  End If

  And do this for each handler, changing the bit being set appropriately.  Then, at the end, you could just check for Me.TrackingUShort = &H7FFF (i.e., all 15 slots set to true) – if that’s a true statement, then everything is in place.

  --Matt Gertz--*
  VB Compiler Dev Lead
  

  
  
  

• m.zirino

  Great, using the "point" method, I was able to turn that glob of IF madness up there, into this:
  
  

  Dim tic As Integer = 0 For i = 1 To 15 If Not ctrl(i).location = Pos(i) Then Exit Sub Else tic = tic + 1 Next i If tic = 15 Then ButtonBar.Items(0).Image = Images.Images(1) ButtonBar.Items(0).Enabled = False My.Computer.Audio.Play(My.Resources.win, AudioPlayMode.Background) MsgBox("you win'd") End If

  
  
  The next question of mine, has to do with program resources, of the CPU/RAM kind.
  
  The last suggestion there, about using a 15 point counter, I've thought about that. Also not knowing how to implement it. So the question then becomes a matter of resources and CPU time.
  
  Think of it this way. This is just for fun, because I highly doubt it has much impact on my little game.
  But anyhoo, compare the two methods with each other.
  
  Using this point method, I've got all kinds of variables, I've got the declaration of the collection, as well as 16 declarations for each point. Then I create the collection and add each point variable into the collection. This is a lot of variables and also extra code for creating the collection in the first place. On the other hand, having my points as variables let's me easily change them if I ever make different sizes etc..without hard coding the point values like I had before.
  
  BUT, using the counter system as in the last suggestion, is there less overhead and code setting that up Is it less processing to check a single block on each click, and set a marker, versus checking ALL blocks on every click It would seem obvious, but I'm not so sure.
  
  What do you guys think I should do Stick with the loop and collections Or try the marker system
  
  (P.S. when this is over I'll let you all download my awesome new game. lol)
  
  

• Dennis G.

  I think the easiest and cleanest way to accomplish your goal would be to inherit the button class.
  I would then add the following:

  Private _LocID as Nullable(Of Integer)

  Public Property LocID() as Nullable(Of Integer)
            Get
                      Return _LocID
            End Get
            Set(ByVal value As Nullable(Of Integer)
                      _LocID = value
            End Set
  End Property

  Public Function IsInPlace() as Booleen
            If Not LocID().HasValue Then Return False
  
            If LocID() = Me.Top
                      Return True
            Else
                      Return False
            End If
  End Function

   

  In the code for the form you could have your win condition checker run through like this:

  Private _Winner as Booleen = True

  Private Property Winner() as Booleen
  

  Private Function IsWinner() as Booleen
            If Not Button1.IsInPlace() Then Return False
            If Not Button2.IsInPlace() Then Return False
            If Not Button3.IsInPlace() Then Return False
            If Not Button4.IsInPlace() Then Return False
            Return True
  End Function
  

   

  The easiest way ever is to create a Component that you select an array of generic buttons with those properties and have the code behind check the status. (Just like a validation checker). I have some code laying around somewhere that does just something like that I just can't find it. If I do I'll be sure to shoot it up.

  
  

• Drickus

  Dim MyLocation1 As New Point(3, 28)
  

  Dim MyLocation2 as New Point(40,28)
  
  If Me.Button1.Location = MyLocation1 And Me.Button2.Location =MyLocation2 Then
  

  messagebox.show("You Win")
  
  End If

  
  
  

• Newbe

  Hi,
  
  

  Vigilante wrote:

  I didn't really have to make 5 IF statements, I could have just had one super long AND AND AND AND AND. But I figured if I do it this way, if the first IF fails, it will exit and not do every check, thus saving a smidgeon of processing time.

  
  
  This isn't really related to your question, but that quote made me wonder...
  At least in C, if you have several AND or OR statements inside an IF, it only checks the necessary conditions to tell if that statement is true or false.
  For instance, imagine you have
  
  

  If (Condition1 and Condition2)

  
  
  In C, if Condition1 returned false, it wouldn't even evaluate Condition2.
  Likewise for OR - if Condition1 was true, even if Condition2 was false it would "enter" the if clause, and as such it wouldn't even evaluate Condition2.
  
  Does anybody know if the same is true for VB.Net
  
  Thanks!
  

• Kunle

  anog- That is called a short circuit. PHP does that also. But not sure if VB does or not. If so, it probably wouldn't hurt to have just one long IF statement.
  
  
  Dman1- I've never heard of that function, is that new to .NET If that works, it would certainly trim some of the code, but essentially would be doing the same thing. Which is fine, but less code is good for me. I will give that a try tonight and see what happens. Thanks.
  
  I was also wondering, then, if this could be used in a loop, rather then as a long IF statement. Can your function, along with my collection, be iterated through
  So instead of "If btn(0).location = xx AND btn(1).location = xx.....". Maybe could I loop through it if the counters match Like maybe:
  
  For i = 0 to 14
  if not btn(i).location = loc(i) then
   exit sub
  else
   you win
  end if
  
  Just quazi code but you get the idea. That would make it so much cleaner. And I'm all for clean, tight code.
  
  thanks again.
  
  

• borgy tan

  It looks to me as you are looking for each button to have a specific form location and that's how you are recognizing them.
  
  Why not create a button class where you have Button(n)
  
  You could give each location a number or actually you could number the locations such that when the buttons are in the right place
  
  Btn 0 = Loc 0
  Btn 1 = Loc 1
  Btn 2 = Loc 3
  
  .
  .
  .
  Btn n = Loc N
  
  If you did this...
  
  For dim I as byte = 1 to 15
  
     If button0 <> loc(i) then return
  
  next
  
  MsgBox "You win"
  
  

  
  
  

• Colin F

  This is the eternal question of “pay later” vs. “pay now.” How you answer it depends on what you’re doing. In the case you’ve described, I would always go for “pay now,” because it scales so well. The user is not going to notice an additional microsecond of bit-setting, since the time for the UI to respond simply by moving the button around dwarfs it by comparison. By delaying it, you’re essentially not only doing all that bit-flipping at the last second, but you’re spending time getting to the memory, accessing it as (probably) an integer, and so on. For 15 buttons this is totally immaterial. Imagine, though, that you had a much more complex puzzle, and then this sort of thing adds up. Bigger puzzle Just increase your bitfield from a UShort to a UInteger or ULong, and life is good – the handler logic is the same, and no voluminous IF statements.
  
  
  
  I’ve worked on a number of similar problems during my career, and I’ve found that *most* of the time it’s better to cache the information in a bitfield simply because I never know how the product (in my case, Visual Basic) will be used at the enterprise level – I get it done at the point where it’s background noise, so I don’t have to sweat it later in one big (possibly noticeable) blob. The only exceptions are when another process is truly blocked on my getting “out” of whatever I’m doing, particularly if I’m in a loop, if (and only if) the bit setting is more expensive.
  
  
  
  Hope this helps,
  
  --Matt--*
  
  

• JedG

  Yes I see the point of using the bit field. I'm going to see if I can implement that.
  
  Though my puzzle will probably not grow or even change, nor will I see a measurable performance difference. I would like to follow best practice programming. I didn't know VB had a built-in function like this, or I would have had to write another method to handle the changing of the bit field.
  
  I'll try to implement this and see what happens.
  
  Thanks.
  
  

• Fraser Putnam

  VB.Net has short circuit keywords if you want that behavior:
  
  OrElse   &  AndAlso
  
  
  ms-help://MS.VSCC.v80/MS.MSDN.v80/MS.VisualStudio.v80.en/dv_vbalr/html/ca474e13-567d-4b1d-a18b-301433705e57.htm
  
  

• alkaline

  Vigilante wrote:

  Dman1- I've never heard of that function, is that new to .NET If that works, it would certainly trim some of the code, but essentially would be doing the same thing. Which is fine, but less code is good for me. I will give that a try tonight and see what happens. Thanks. I was also wondering, then, if this could be used in a loop, rather then as a long IF statement. Can your function, along with my collection, be iterated through So instead of "If btn(0).location = xx AND btn(1).location = xx.....". Maybe could I loop through it if the counters match Like maybe: thanks again.

  
  
  Location is a method of the control object that is a "point" and yes you can iterate through the buttons and locations as you mentioned in code.
  
  

• MikeFesta

  Sounds good, except I don't know how!
  
  I did figure out one thing though. I can create a new object collection and add all my buttons to it. Such as this:
  
  

  Dim ctrl As Collection

  
  
  And then I fill it up will my buttons like this:
  
  

  ctrl = New Collection ctrl.Add(B1, "1") ctrl.Add(B2, "2") ctrl.Add(B3, "3") ctrl.Add(B4, "4") ............

  
  
  And then I can reference them like this:
  
  

  ctrl(I).left ctrl(I).top

  
  
  However, for what you are saying, how would VB make the connection of "top" and "left" values to a single variable called "loc1" which has both values contained in it such as "if ctrl(I) = loc(I) Then...". I don't get it.
  
  Like if I was coding, say, "move btn1 to loc1". This is still a function I have to write to handle changing left and top values. So I don't see the connection.
  
  It is a primitive way to make a game, but it's very simple. Just taking the actual button object and move it around by left and top attributes. In order to win, B1 HAS to be at 3,28; and B2 HAS to be at 40,28; and so on. So I guess I'm not seeing the automation of your idea.
  
  If you could maybe create an example, say with a 2x2 grid for simplicity sake. Or tell me how I can use my object collection to do it. That would be great. Cause like I said, this IF mess works, I just think there must be a cleaner way to do it.
  
  
• Any way to trim all these IF statements?