Task

Write a player of the Bulls and Cows game, rather than a scorer. The player should give intermediate answers that respect the scores to previous attempts.

One method is to generate a list of all possible numbers that could be the answer, then to prune the list by keeping only those numbers that would give an equivalent score to how your last guess was scored. Your next guess can be any number from the pruned list.

Either you guess correctly or run out of numbers to guess, which indicates a problem with the scoring.



Related tasks

   Bulls and cows
   Guess the number
   Guess the number/With Feedback (Player)


 
Option Explicit
 
Sub Main_Bulls_And_Cows_Player()
Dim collSoluces As New Collection, Elem As Variant, Soluce As String
Dim strNumber As String, cpt As Byte, p As Byte
Dim i As Byte, Bulls() As Boolean, NbBulls As Byte, Cows As Byte, Poss As Long
Const NUMBER_OF_DIGITS As Byte = 4
 
        strNumber = CreateNb(NUMBER_OF_DIGITS)
        Debug.Print "TOSS : " & StrConv(strNumber, vbUnicode)
        Debug.Print "---------- START ------------"
        Set collSoluces = CollOfPossibleNumbers
        Poss = collSoluces.Count
        For Each Elem In collSoluces
            'Debug.Print "Number of possibilities : " & Poss
            Debug.Print "Attempt : " & StrConv(Elem, vbUnicode)
            NbBulls = 0: Soluce = Elem
            ReDim Bulls(NUMBER_OF_DIGITS - 1)
            For i = 1 To NUMBER_OF_DIGITS
                If IsBull(strNumber, Mid(Elem, i, 1), i) Then
                    Bulls(i - 1) = True: NbBulls = NbBulls + 1
                    RemoveIfNotBull collSoluces, Mid(Elem, i, 1), i
                End If
            Next i
            Cows = 0
            For i = 1 To NUMBER_OF_DIGITS
                If Not Bulls(i - 1) Then
                    If IsCow(collSoluces, strNumber, Mid(Elem, i, 1), p) Then
                        If Not Bulls(p - 1) Then Cows = Cows + 1
                    End If
                End If
            Next i
            Poss = collSoluces.Count
            Debug.Print "Bulls : " & NbBulls & ", Cows : " & Cows
            If Poss = 1 Then Exit For
        Next
                Debug.Print "---------- THE END ------------"
        Debug.Print "TOSS WAS : " & StrConv(strNumber, vbUnicode) & " We found : " & StrConv(Soluce, vbUnicode)
End Sub
 
Function CreateNb(NbDigits As Byte) As String
Dim myColl As New Collection
Dim strTemp As String
Dim bytAlea As Byte
 
    Randomize
    Do
        bytAlea = Int((Rnd * 9) + 1)
        On Error Resume Next
        myColl.Add CStr(bytAlea), CStr(bytAlea)
        If Err <> 0 Then
            On Error GoTo 0
        Else
            strTemp = strTemp & CStr(bytAlea)
        End If
    Loop While Len(strTemp) < NbDigits
    CreateNb = strTemp
End Function
 
Function CollOfPossibleNumbers() As Collection
Dim TempColl As New Collection
Dim x As String
Dim i As Long
Dim Flag As Boolean
Dim b As Byte
 
    For i = 1234 To 9876
        Flag = False
        For b = 1 To 4
            x = CStr(i)
            If Len(Replace(x, Mid(x, b, 1), "")) < 3 Then
                Flag = True: Exit For
            End If
        Next
        If Not Flag Then TempColl.Add x, x
    Next i
    Set CollOfPossibleNumbers = TempColl
End Function
 
Function IsBull(strgNb As String, Digit As String, place As Byte) As Boolean
    IsBull = (Mid(strgNb, place, 1) = Digit)
End Function
 
Function IsCow(C As Collection, strgNb As String, Digit As String, place As Byte) As Boolean
    If (InStr(strgNb, Digit) > 0) Then
        IsCow = True: place = InStr(strgNb, Digit)
        RemoveIfNotCow C, Digit
    End If
End Function
 
Sub RemoveIfNotBull(C As Collection, Digit As String, place As Byte)
Dim E As Variant
 
    For Each E In C
        If Mid(E, place, 1) <> Digit Then C.Remove E
    Next
End Sub
 
Sub RemoveIfNotCow(C As Collection, Digit As String)
Dim E As Variant
 
    For Each E In C
        If (InStr(E, Digit) = 0) Then C.Remove E
    Next
End Sub
 