'--- Declaration of global variables ---
Dim As String colors(1 To 4) => {"A", "B", "C", "D"}
Dim Shared As Integer nr, ub', numlet=4, lencod=4
Dim Shared As String*4 master, pz
ub = Ubound(colors)
nr = 0

'--- SUBroutines and FUNCtions ---
Sub Encabezado
    Dim As String dup
    Color 11: Print "Welcome to Mastermind"
    Print "=====================" + Chr(13) + Chr(10) : Color 15
    Print "You will need to guess a random code."
    Print "For each guess, you will receive a hint:"
    Print "X - denotes a correct letter,"
    Print "O - denotes a letter in the original"
    Print "    string but a different position."
    Print "You have 12 attempts."
    Print "Duplicates are not allowed." + Chr(10)
    Print "Good luck!" + Chr(10) + Chr(10) : Color 7
End Sub

Sub showresult(test() As String, place1 As Byte, place2 As Byte, place3 As Byte)
    Dim As Integer r, n1, n2, n3
    Print Using "##: "; nr;
    For r = 1 To Ubound(test)
        Print test(r);
    Next R
    Print "  : ";
    For n1 = 1 To place1
        Print "X"; " ";
    Next N1
    For n2 = 1 To place2
        Print "O"; " ";
    Next N2
    For n3 = 1 To place3
        Print "-"; " ";
    Next N3
    Print : Print
End Sub

Sub Inicio
    Dim As Integer mind(ub), rands(ub)
    Dim As Integer n, aleat
    Dim As Boolean repeat = false

    For n = 1 To ub
        While true
            aleat = (Rnd * (ub-1)) + 1
            If rands(aleat) <> 1 Then
                mind(n) = aleat
                rands(aleat) = 1
                Exit While
            End If
        Wend
    Next n

    For n = 1 To ub
        Mid(master,n,1) = Chr(64 + mind(n))
        pz &= Chr(64 + mind(n))
    Next n
End Sub


'--- Main Program ---
Randomize Timer
Cls
Dim As Integer guesses = 12
Encabezado
Inicio
Color 15: Print pz : Color 7
Do
    Dim As Integer n, p, d, x, posic
    Dim As Integer places(1 To 2), place1, place2, place3
    Dim As String*4 testbegin
    Dim As String test(ub), mastertemp, tmp
    Dim As Boolean flag = True

    For p = 1 To Ubound(places)
        places(p) = 0
    Next p
    nr += 1
    Input "Your guess (ABCD)? " , testbegin
    For d = 1 To Ubound(test)
        test(d) = Mid(testbegin,d,1)
    Next d

    For n = 1 To Ubound(test)
        If Ucase(test(n)) <> Mid(master,n,1) Then flag = False
    Next n
    If flag = True Then
        Color 10: Print !"\nWell done! You guess correctly." : Sleep : Exit Do
    Else
        For x = 1 To Len(master)
            If Ucase(test(x)) = Mid(master,x,1) Then places(1) += 1
        Next x
        mastertemp = master
        For p = 1 To Ubound(test)
            posic = Instr(mastertemp, Ucase(test(p)))
            If posic > 0 Then
                tmp = mastertemp
                mastertemp = Left(tmp,posic-1) + Mid(tmp, posic+1, Len(tmp)-1)
                places(2) += 1
            End If
        Next p
    End If
    place1 = places(1)
    place2 = places(2) - place1
    place3 = Len(master) - (place1 + place2)
    showresult(test(), place1, place2, place3)
Loop Until nr = guesses
Color 14: Print "The correct combination was: "; pz
Color 7: Print !"\nEnd of game"
Sleep