Module Module1

    Public Class Fraction

        Private numerator As Integer
        Private denominator As Integer

        'Create a fraction by passing in the numerator
        'and denominator
        Public Sub New(ByVal numerator As Integer, ByVal denominator As Integer)
            Me.numerator = numerator
            Me.denominator = denominator
        End Sub

        'Overloaded operator- takes two fractions
        'and returns their sum
        Public Shared Operator -(ByVal lhs As Fraction, ByVal rhs As Fraction) As Fraction
            Dim firstProduct As Integer = 0
            Dim secondProduct As Integer = 0

            'Like fractions (shared denominator) can be added
            'by adding thier numerators
            If (lhs.denominator = rhs.denominator) Then
                Return New Fraction(lhs.numerator - rhs.numerator, lhs.denominator)
            End If
            'Simplistic solution for unlike fractions
            firstProduct = (lhs.numerator * rhs.denominator) - (rhs.numerator * lhs.denominator)
            secondProduct = lhs.denominator * rhs.denominator

            Return New Fraction(firstProduct, secondProduct)
        End Operator

        'Return a string representation of the fraction
        Public Overrides Function ToString() As String
            Dim s As String = numerator.ToString() + "/" + denominator.ToString()
            Return s
        End Function
    End Class

    Public Class Tester

        Public Sub Run()

            Dim f1 As Fraction = New Fraction(1, 2)
            Console.WriteLine("f1: {0}", f1.ToString())

            Dim f2 As Fraction = New Fraction(1, 6)
            Console.WriteLine("f2: {0}", f2.ToString())

            Dim f3 As Fraction = f1 - f2
            Console.WriteLine("f1 - f2 = f3: {0}", f3.ToString())

        End Sub

    End Class

    Sub Main()

        Dim t = New Tester()
        t.Run()

        Console.ReadLine()
    End Sub

End Module