Module Module1
    Sub Main()
        'while loop keeps the program running without need to restart for testing purposes
        While true
            'Variable Definitions

            'defines the vending machine choices as a 2-dimensional string array
            'defined as a string array to make it easier to print, as the prices can be changed into decimals for calculations using decimal.parse()
            Dim choices = New String()() _
                    {({"KitKat", "1.51"}), ({"Yorkie", "1.00"}), ({"Crunchie", "1.20"}), ({"Coke", "1.30"}),
                     ({"Fanta", "0.90"}),
                     ({"Malteasers", "1.50"}), ({"Granola Bar", "1.51"}), ({"Dr. Pepper", "0.85"}),
                     ({"Double Decker", "1.10"}), ({"Lemonade", "1.29"})}
            'All non-integer values are defined as decimals rather than floats otherwise calculations don't work properly.
            Dim money As decimal
            Dim choice As integer
            Dim price as decimal
            'this array is to store the number of each coin used, with 0 being £2 and 7 being 1p
            Dim counter(7) as Integer
            Dim change As decimal


            'tells them to enter the value, asks for it as a decimal number as using the pound sign will throw an exception as it is expecting a decimal
            Console.WriteLine("Enter the value you wish to insert, as a decimal number.")
            money = Console.ReadLine()

            Console.WriteLine("You have inserted £" & money)
            Console.WriteLine("Please select your choice")


            'loops through the 2 dimensional array to output a list of all the options in the vending machine
            For index As Integer = 0 To 9
                Console.write(index + 1 & ". ")
                Console.Write(choices(index)(0))
                console.write("----£")
                console.writeline(choices(index)(1))

            Next

            'takes the users choice and then subtracts one to deal with 0-base array indexing
            choice = Console.readline()
            choice = choice - 1
            'checks if the choice is within the allowed range
            If choice > 9 Or choice < 0 Then
                console.WriteLine("Invalid Choice")

            Else
                'checks to see if they have entered enough money for their choice
                price = decimal.Parse(choices(choice)(1))
                If price > money Then
                    Console.WriteLine("Not enough money entered")
                Else

                    'calculates the amount of change that needs to be given
                    change = money - price

                    'While the amount of change left to give is not 0, it will find the largest coin it can use and subtract that from the amount of change left, making a note of the coin used
                    While change <> 0
                        Select case change
                            Case is >= 2
                                change = change - 2.00
                                counter(7) = counter(7) + 1
                            Case 1 To 1.99
                                change = change - 1.00
                                counter(6) = counter(6) + 1
                            Case 0.5 to 0.99
                                'the numbers must be defined as decimal otherwise calculations do not work due to rounding errors
                                change = change - new Decimal(0.5)
                                counter(5) = counter(5) + 1
                            Case 0.2 To 0.49
                                change = change - New Decimal(0.2)
                                counter(4) = counter(4) + 1
                            Case 0.1 to 0.19
                                change = change - new Decimal(0.1)
                                counter(3) = counter(3) + 1
                            case 0.05 To 0.09
                                change = change - New Decimal(0.05)
                                counter(2) = counter(2) + 1
                            case 0.02 to 0.04
                                change = change - New decimal(0.02)
                                counter(1) = counter(1) + 1
                            case 0.01
                                change = change - New decimal(0.01)
                                counter(0) = counter(0) + 1


                        End Select
                    End While

                    'outputs how many of each coin was used for change
                    console.WriteLine("---------Change--------)")
                    Console.WriteLine(counter(7) & "- £2.00")
                    Console.WriteLine(counter(6) & "- £1.00")
                    Console.WriteLine(counter(5) & " - 50p")
                    Console.WriteLine(counter(4) & " - 20p")
                    Console.WriteLine(counter(3) & "- 10p")
                    Console.WriteLine(counter(2) & "- 5p")
                    Console.WriteLine(counter(1) & "- 2p")
                    Console.WriteLine(counter(0) & "- 1p")


                End If


            End If


            Console.ReadLine()
        end while
    End Sub
End Module