Imports System

Public Module Module1

    Public Sub Main()

        Const minpH as Double = 0.0

        Const maxpH as Double = 14.0

        Dim pHday(3), pHnight(3) as Double

        Dim highestpH, lowestpH, ttlpHday, ttlpHnight, avgpHday, avgpHnight as Double

        Dim count, highestpHday, lowestpHnight As Integer

        highestpH = 0.0

        lowestpH = 14.0

        highestpHday = 0

        lowestpHnight = 0

        'ttlpHday = 0.0

        'ttlpHnight = 0.0

        For count = 1 To 3

        Do

        Console.WriteLine("Enter value for pH during the day.")

        pHday(count) = Console.ReadLine()

            If pHday(count) < 0.0 OR pHday(count) > 14.0 Then

            Console.WriteLine("Invalid noon pH!!!") 

        End If

        Loop Until pHday(count) >= minpH AND pHday(count) <= maxpH

        Do

        Console.WriteLine("Enter value for pH during the night.")

        pHnight(count) = Console.ReadLine()

        If pHnight(count) < 0.0 OR pHnight(count) > 14.0 Then

                Console.WriteLine("Invalid midnight pH!!!") 

        End If

        Loop Until pHnight(count) >= minpH AND pHnight(count) <= maxpH

        If pHday(count) > highestpH Then

            highestpH = pHday(count)

            highestpHday = count

        End If

        If pHnight(count) < lowestpH Then

            lowestpH = pHnight(count)

            lowestpHnight = count

        End If

        ttlpHday = ttlpHday + pHday(count)

        ttlpHnight = ttlpHnight + pHnight(count)

        Next

        avgpHday = ttlpHday/3

        avgpHnight = ttlpHnight/3

        Console.WriteLine("Average day pH is " &avgpHday)

        Console.WriteLine("Average night pH is " &avgpHnight)

        Console.WriteLine("Highest pH at noon is " & highestpH & " on day " & highestpHday)

        Console.WriteLine("Lowest pH at midnight is " & lowestpH & " on day " & lowestpHnight)

    End Sub

End Module