Imports System

Imports System.IO

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Module Module1

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    Private aQuestions(4, 4) As String

    Private aCorrectQuestions(4, 1) As String

    Sub Main()

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        'initialize sFileQuestions with the file location of Questions

        'initialize sFileAnswers with the file location of the Answers

        Dim sFileQuestions As String = "D:\Files\rivers.txt"

        Dim sFileAnswers As String = "D:\Files\answer.txt"

        Dim sFileCorrect As String = "D:\Files\riverlengths.txt"

​

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        'read the rivers and options in the question file 

        'and store the data in the aQuestions array

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        Dim sr As New StreamReader(sFileQuestions)

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        Do While sr.Peek() <> -1

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            For n = 0 To 4

                For i = 0 To 4

                    aQuestions(n, i) = aQuestions(n, i) & sr.ReadLine()

                Next

            Next

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        Loop

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        'first column stores name, next columns store lengths - in text form 

        'print out rivers and options all on one line. 

        'e.g., "Nile River , 6300 6275 6650 6400"

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        For i = 0 To 4

            Console.Write(aQuestions(i, 0) & " River , ")

            For n = 1 To 4

                Console.Write(aQuestions(i, n) & " ")

            Next

            Console.WriteLine()

        Next

​

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        'read the correct option answers in the answer file

        'and store the data in the array aAnswers

        Dim aAnswers(4) As Integer

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        Dim oSr As New StreamReader(sFileAnswers)

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        Do While oSr.Peek() <> -1

            For n = 0 To 4

                aAnswers(n) = aAnswers(n) & oSr.ReadLine() & vbNewLine

            Next

        Loop

​

​

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        'print out river names and correct lengths

        For n = 0 To 4

            Console.WriteLine(aQuestions(n, 0) & " river" & " is " & aQuestions(n, aAnswers(n)) & "km long")

        Next

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        'e.g., "Nile River is 6650 km long"

​

​

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        'Store the correct information in a file called "RiverLengths.txt"

        'store the file in the same folder as the other files.

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        Using sw As StreamWriter = File.AppendText(sFileCorrect)

            For n = 0 To 4

                sw.WriteLine(aQuestions(n, 0) & vbCrLf & aQuestions(n, aAnswers(n)))

            Next

​

        End Using

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        'Print out rivers names and lengths in alphabetical order

        'hint sort the rivers array using a modified bubble sort.

        'print out the river name and correct length

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        Dim lsr As New StreamReader(sFileCorrect)

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        Do While lsr.Peek() <> -1

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            For n = 0 To 4

                For i = 0 To 1

                    aCorrectQuestions(n, i) = aCorrectQuestions(n, i) & lsr.ReadLine()

                Next

            Next

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        Loop

​

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        Dim lastUnsortedPos As Integer

        Dim temp As String

        Dim j As Integer

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        lastUnsortedPos = 4

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        For i = 0 To 4

            lastUnsortedPos = lastUnsortedPos - 1

            For j = 0 To lastUnsortedPos

                If aCorrectQuestions(j, 0) > aCorrectQuestions(j + 1, 0) Then

                    temp = aCorrectQuestions(j, 0)

                    aCorrectQuestions(j, 0) = aCorrectQuestions(j + 1, 0)

                    aCorrectQuestions(j + 1, 0) = temp

                End If

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            Next

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        Next

        Console.WriteLine()

        Console.WriteLine("Array Sorted Alphabetically :")

        For n = 0 To 4

​

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            Console.WriteLine(aQuestions(n, 0) & " river" & " is " & aQuestions(n, aAnswers(n)) & "km long")

        Next

        Console.ReadLine()

    End Sub

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End Module