Option Explicit

Private Sub InitSet(SetA() As Boolean, ParamArray NumberList())
 Dim i As Long
 For i = LBound(SetA) To UBound(SetA)
    SetA(i) = False
 Next i
 For i = LBound(NumberList) To UBound(NumberList)
    'If (NumberList(i) >= LBound(SetA)) And (NumberList(i) <= UBound(SetA)) Then
       SetA(NumberList(i)) = True
    'End If
 Next i
End Sub

Private Sub SetAnd(SetA() As Boolean, SetB() As Boolean, SetC() As Boolean)
 Dim i As Long
 For i = LBound(SetC) To UBound(SetC)
    SetC(i) = SetA(i) And SetB(i)
 Next i
End Sub

Private Sub SetOr(SetA() As Boolean, SetB() As Boolean, SetC() As Boolean)
 Dim i As Long
 For i = LBound(SetC) To UBound(SetC)
    SetC(i) = SetA(i) Or SetB(i)
 Next i
End Sub

Private Sub SetXor(SetA() As Boolean, SetB() As Boolean, SetC() As Boolean)
 Dim i As Long
 For i = LBound(SetC) To UBound(SetC)
    SetC(i) = SetA(i) Xor SetB(i)
 Next i
End Sub

Private Sub DisplaySet(SetA() As Boolean)
 Dim s As String
 Dim i As Long
 For i = LBound(SetA) To UBound(SetA)
    If SetA(i) Then s = s & i & ", "
 Next i
 If Len(s) Then s = Left$(s, Len(s) -  2 )
 MsgBox s, vbInformation, "Множество"
End Sub

Public Sub Test()
 Dim SetA( 1  To  100 ) As Boolean
 Dim SetB( 1  To  100 ) As Boolean
 Dim SetC( 1  To  100 ) As Boolean
 
 InitSet SetA,  1 ,  2 ,  5 ,  7 ,  8 
 InitSet SetB,  1 ,  4 ,  5 ,  8 ,  13 
' InitSet SetC

 SetAnd SetA, SetB, SetC
 DisplaySet SetC
 
 SetOr SetA, SetB, SetC
 DisplaySet SetC
 
 SetXor SetA, SetB, SetC
 DisplaySet SetC
End Sub