Algo/Code help for tictactoe ai

[dday9]

Dunno if I should post this in the vb.net section or not, but I'm having a tough time wrapping my head around the ai code for my tictactoe game. I know very little about the min/max algorithm, but I do kinda understand the basics of it. Here is what I'm using right now for my ai:

If player1Turn = False Then
            'Block wins
            If Button1.Text = "X" And Button2.Text = "X" And Button3.Text = String.Empty Then
                Button3.Text = "O"
            ElseIf Button1.Text = "X" And Button4.Text = "X" And Button7.Text = String.Empty Then
                Button7.Text = "O"
            ElseIf Button1.Text = "X" And Button5.Text = "X" And Button9.Text = String.Empty Then
                Button9.Text = "O"
            ElseIf Button4.Text = "X" And Button5.Text = "X" And Button6.Text = String.Empty Then
                Button6.Text = "O"
            ElseIf Button2.Text = "X" And Button5.Text = "X" And Button8.Text = String.Empty Then
                Button8.Text = "O"
            ElseIf Button3.Text = "X" And Button5.Text = "X" And Button7.Text = String.Empty Then
                Button7.Text = "O"
            ElseIf Button7.Text = "X" And Button8.Text = "X" And Button9.Text = String.Empty Then
                Button9.Text = "O"
            ElseIf Button3.Text = "X" And Button6.Text = "X" And Button9.Text = String.Empty Then
                Button9.Text = "O"

                'If cpu can win
            ElseIf Button1.Text = "O" And Button2.Text = "O" And Button3.Text = String.Empty Then
                Button3.Text = "O"
            ElseIf Button1.Text = "O" And Button4.Text = "O" And Button7.Text = String.Empty Then
                Button7.Text = "O"
            ElseIf Button1.Text = "O" And Button5.Text = "O" And Button9.Text = String.Empty Then
                Button9.Text = "O"
            ElseIf Button4.Text = "O" And Button5.Text = "O" And Button6.Text = String.Empty Then
                Button6.Text = "O"
            ElseIf Button2.Text = "O" And Button5.Text = "O" And Button8.Text = String.Empty Then
                Button8.Text = "O"
            ElseIf Button3.Text = "O" And Button5.Text = "O" And Button7.Text = String.Empty Then
                Button7.Text = "O"
            ElseIf Button7.Text = "O" And Button8.Text = "O" And Button9.Text = String.Empty Then
                Button9.Text = "O"
            ElseIf Button3.Text = "O" And Button6.Text = "O" And Button9.Text = String.Empty Then
                Button9.Text = "O"
            Else
                'If there are no possibilities to win or block user's  win


            End If
        End If

basically the board looks like this:
button1 | button2 | button3
button4 | button5 | button6
button7 | button8 | button9

as you can tell, I hardcoded the possible wins and possible blocks, now what I'm stuck on is if it's the computer's turn and there are no possibilities to win or block the user's win. Any help or suggestions.

Edit - This isn't much of an edit to the code, but I changed the button.text to button.performclick. It works better that way.

[dday9]

I got something, although I really don't like how it works:

If pvp = False Then
            If player1Turn = False Then
 
                'If cpu can win
                If Button1.Text = "O" And Button2.Text = "O" And Button3.Text = String.Empty Then
                    Button3.PerformClick()
                ElseIf Button1.Text = "O" And Button4.Text = "O" And Button7.Text = String.Empty Then
                    Button7.PerformClick()
                ElseIf Button1.Text = "O" And Button5.Text = "O" And Button9.Text = String.Empty Then
                    Button9.PerformClick()
                ElseIf Button4.Text = "O" And Button5.Text = "O" And Button6.Text = String.Empty Then
                    Button6.PerformClick()
                ElseIf Button2.Text = "O" And Button5.Text = "O" And Button8.Text = String.Empty Then
                    Button8.PerformClick()
                ElseIf Button3.Text = "O" And Button5.Text = "O" And Button7.Text = String.Empty Then
                    Button7.PerformClick()
                ElseIf Button7.Text = "O" And Button8.Text = "O" And Button9.Text = String.Empty Then
                    Button9.PerformClick()
                ElseIf Button3.Text = "O" And Button6.Text = "O" And Button9.Text = String.Empty Then
                    Button9.PerformClick()
                    'Block wins
                ElseIf Button1.Text = "X" And Button2.Text = "X" And Button3.Text = String.Empty Then
                    Button3.PerformClick()
                ElseIf Button1.Text = "X" And Button4.Text = "X" And Button7.Text = String.Empty Then
                    Button7.PerformClick()
                ElseIf Button1.Text = "X" And Button5.Text = "X" And Button9.Text = String.Empty Then
                    Button9.PerformClick()
                ElseIf Button4.Text = "X" And Button5.Text = "X" And Button6.Text = String.Empty Then
                    Button6.PerformClick()
                ElseIf Button2.Text = "X" And Button5.Text = "X" And Button8.Text = String.Empty Then
                    Button8.PerformClick()
                ElseIf Button3.Text = "X" And Button5.Text = "X" And Button7.Text = String.Empty Then
                    Button7.PerformClick()
                ElseIf Button7.Text = "X" And Button8.Text = "X" And Button9.Text = String.Empty Then
                    Button9.PerformClick()
                ElseIf Button3.Text = "X" And Button6.Text = "X" And Button9.Text = String.Empty Then
                    Button9.PerformClick()
                Else
 
                    'If there are no possibilities to win or block user's  win
                    If Button1.Enabled = True Then
                        Button1.PerformClick()
                    ElseIf Button9.Enabled = True Then
                        Button9.PerformClick()
                    ElseIf Button2.Enabled = True Then
                        Button2.PerformClick()
                    ElseIf Button8.Enabled = True Then
                        Button8.PerformClick()
                    ElseIf Button3.Enabled = True Then
                        Button3.PerformClick()
                    ElseIf Button7.Enabled = True Then
                        Button7.PerformClick()
                    ElseIf Button4.Enabled = True Then
                        Button4.PerformClick()
                    ElseIf Button6.Enabled = True Then
                        Button6.PerformClick()
                    ElseIf Button5.Enabled = True Then
                        Button5.PerformClick()
                    End If
 
                End If
            End If
        End If

If y'all could help refine it, I'm up for suggestions.

[boops boops]

Does the logic now work as intended? If so, what don't you like?

If I were coding it myself, I think I would use a 9-member array of integers instead of keeping the game data in the button texts; the integer values could be 0=empty, 1=X, 2=O. Then I would code a single event sub to handle all the button clicks. This sub would update the array, change the clicked button's text and disable it, and call the computer-move sub. This sub would check the array values using similar logic to your code, although I would prefer a Select-Case statement to all those ElseIfs. For its move, it would change the button text and enabled state as well as updating the array. But then I just don't like PerformClick.

By the way, what is the min/max algorithm?

BB

[dday9]

Does the logic now work as intended? If so, what don't you like?

If you play corners, or the same thing over and over again, then it takes the same path.

the integer values could be 0=empty, 1=X, 2=O

I didn't think about that, I'm going to change to storing values as an int array.

Select-Case statement to all those ElseIfs

I don't usually do select/case's, simply because I rarely find a use for them in my usual(non game programming) code. But I do see where it'd be easier.

By the way, what is the min/max algorithm?

You can find it on wiki here, but simplified; It's an algorithm for 2 player games where player2's the best move/play is based on the play of player1. Pretty much think of it as an if/then statement. If I click on button1 then is button2,3,4 ect. my best move? And if I do choose, say button2, then what are the possibilities after that? Or another good example is to think of it as a tree, as shown here:

[dday9]

Here is something much more random that I started using:

Private Function randomBtn() As Button
        Dim list As New List(Of Button)
        For Each btn As Button In Panel1.Controls.OfType(Of Button)()
            If btn.Enabled = True Then
                list.Add(btn)
            End If
        Next
        Dim r As New Random
        Dim i As Integer
        i = r.Next(0, list.Count - 1)
        randomBtn = list.Item(i)

    End Function

I like that much more :]