VB Asgn 1.2

Public Class AnswerNumericalStatistic
    'Clears the AnswerTextBox when the form is loaded'
    Private Sub Me_Load(sender As Object, e As EventArgs) Handles Me.Load
        AnswerTextBox.Text = ""
    End Sub

    Private Sub LargestButton_Click(sender As Object, e As EventArgs) Handles LargestButton.Click
        AnswerTextBox.Text = ""
        Dim max As Double = NumericalStatistic.ValueTextBox.Lines(0)

        'Compare and find the largest number'
        For i As Integer = 1 To NumericalStatistic.ValueTextBox.Lines.Length - 1
            If NumericalStatistic.ValueTextBox.Lines(i) > max Then
                max = NumericalStatistic.ValueTextBox.Lines(i)
            End If
        Next

        AnswerTextBox.Text = max
    End Sub

    Private Sub SmallestButton_Click(sender As Object, e As EventArgs) Handles SmallestButton.Click
        AnswerTextBox.Text = ""
        Dim min As Double = NumericalStatistic.ValueTextBox.Lines(0)

        'Compare and find the smallest number'
        For i As Integer = 1 To NumericalStatistic.ValueTextBox.Lines.Length - 1
            If NumericalStatistic.ValueTextBox.Lines(i) < min Then
                min = NumericalStatistic.ValueTextBox.Lines(i)
            End If
        Next

        AnswerTextBox.Text = min
    End Sub

    Private Sub MeanButton_Click(sender As Object, e As EventArgs) Handles MeanButton.Click
        AnswerTextBox.Text = ""
        AnswerTextBox.Text = CalculateMean()
    End Sub

    Private Sub ModeButton_Click(sender As Object, e As EventArgs) Handles ModeButton.Click
        AnswerTextBox.Text = ""

        Dim modeArray(NumericalStatistic.ValueTextBox.Lines.Length, 1) As Double
        Dim highestFrequency As Double = 0
        Dim count As Integer = 0

        'Filter out repeating numbers (make array without repeating no.)'
        For Each line As String In NumericalStatistic.ValueTextBox.Lines
            Dim found As Boolean = False

            'check if there is any numbers in modeArray that is the same as the line'
            For i As Integer = 0 To NumericalStatistic.ValueTextBox.Lines.Length - 1
                'the modeArray right index 0 is the Values'
                If modeArray(i, 0) = line Then
                    found = True
                End If
            Next

            If Not found Then
                modeArray(count, 0) = line
                count += 1
            End If
        Next

        'Count frequency of each number in the modeArray'
        For Each line As String In NumericalStatistic.ValueTextBox.Lines
            For i As Integer = 0 To NumericalStatistic.ValueTextBox.Lines.Length - 1
                If line = modeArray(i, 0) Then
                    'the modeArray right index 1 is the Frequency'
                    modeArray(i, 1) += 1
                End If
            Next
        Next

        'Find mode, similar to finding the largest'
        Dim modes(count) As Double
        Dim count2 As Integer = 0
        For i As Integer = 0 To count
            If modeArray(i, 1) > highestFrequency Then
                highestFrequency = modeArray(i, 1)
                modes(0) = modeArray(i, 0)
            End If
        Next

        'Check if got multiple mode'
        For i As Integer = 0 To count
            If modeArray(i, 1) = highestFrequency AndAlso modeArray(i, 0) <> modes(0) Then
                count2 += 1
                modes(count2) = modeArray(i, 0)
            End If
        Next

        AnswerTextBox.Text = modes(0)
        'If there is more than 1 mode'
        If count2 > 0 Then
            For i As Integer = 1 To count2
                AnswerTextBox.Text = AnswerTextBox.Text & "," & modes(i)
            Next
        End If
    End Sub

    Private Sub MedianButton_Click(sender As Object, e As EventArgs) Handles MedianButton.Click
        AnswerTextBox.Text = ""
        Dim sortedInput() As Double = SortArray()
        Dim position As Integer
        Dim num1, num2, median As Double

        'Even number of input'
        If sortedInput.Length Mod 2 = 0 Then
            'Find position of number closest to middle'
            position = sortedInput.Length / 2
            num1 = sortedInput(position)
            num2 = sortedInput(position - 1)
            median = (num1 + num2) / 2
        'Odd'
        Else
            'Find position of median'
            position = (sortedInput.Length - 1) / 2
            median = sortedInput(position)
        End If

        AnswerTextBox.Text = median
    End Sub

    Private Sub FirstQuartileButton_Click(sender As Object, e As EventArgs) Handles FirstQuartileButton.Click
        AnswerTextBox.Text = ""
        AnswerTextBox.Text = CalculateFirstQuartile()
    End Sub

    Private Sub ThirdQuartileButton_Click(sender As Object, e As EventArgs) Handles ThirdQuartileButton.Click
        AnswerTextBox.Text = ""
        AnswerTextBox.Text = CalculateThirdQuartile()
    End Sub

    Private Sub InterquartileButton_Click(sender As Object, e As EventArgs) Handles InterquartileButton.Click
        AnswerTextBox.Text = ""
        'Calculate difference between 1st and 3rd Quartile'
        Dim interQRange As Double = CalculateThirdQuartile() - CalculateFirstQuartile()
        AnswerTextBox.Text = interQRange
    End Sub

    Private Sub VarianceButton_Click(sender As Object, e As EventArgs) Handles VarianceButton.Click
        AnswerTextBox.Text = ""
        AnswerTextBox.Text = CalculateVariance()
    End Sub

    Private Sub StandardDeviationButton_Click(sender As Object, e As EventArgs) Handles StandardDeviationButton.Click
        AnswerTextBox.Text = ""
        'Square root variance to get Standard Deviation'
        Dim standardDeviation As Double = Math.Sqrt(CalculateVariance())
        AnswerTextBox.Text = stDeviation
    End Sub

    Function CalculateMean() As Double
        'mean = average'
        Dim sum As Double = 0.0
        Dim mean As Double = 0.0

        For Each number As Double In NumericalStatistic.ValueTextBox.Lines
            sum += number
        Next

        mean = sum / (NumericalStatistic.ValueTextBox.Lines.Length)

        Return mean
    End Function

    Function CalculateFirstQuartile() As Double
        Dim sortedInput() As Double = SortArray()
        Dim position As Integer
        Dim num1, num2, firstQ As Double

        'Even number of input'
        If sortedInput.Length Mod 2 = 0 Then
            'Total number divided by 2 is even'
            If ((sortedInput.Length) Mod 4 = 0) Then
                position = sortedInput.Length / 4
                num1 = sortedInput(position)
                num2 = sortedInput(position - 1)
                firstQ = (num1 + num2) / 2
            'Total number divided by 2 is odd'
            Else
                position = ((sortedInput.Length) / 4)
                firstQ = sortedInput(position)
            End If
        'Odd number of input'
        Else
            'Total number-1 divided by 2 is even'
            If (sortedInput.Length - 1) Mod 4 = 0 Then
                position = (sortedInput.Length - 1) / 4
                num1 = sortedInput(position)
                num2 = sortedInput(position - 1)
                firstQ = (num1 + num2) / 2
            'Total number-1 divided by 2 is odd'
            Else
                position = ((sortedInput.Length + 1) / 4) - 1
                firstQ = sortedInput(position)
            End If
        End If

        Return firstQ
    End Function

    Function CalculateThirdQuartile() As Double
        Dim sortedInput() As Double = SortArray()
        Dim position As Integer
        Dim num1, num2, thirdQ As Double

        'Even number of input'
        If sortedInput.Length Mod 2 = 0 Then
            'Total number divided by 2 is even'
            If ((sortedInput.Length) Mod 4 = 0) Then
                position = 3 * sortedInput.Length / 4
                num1 = sortedInput(position)
                num2 = sortedInput(position - 1)
                thirdQ = (num1 + num2) / 2
            'Total number divided by 2 is odd'
            Else
                position = (3 * (sortedInput.Length) / 4)
                thirdQ = sortedInput(position)
            End If
        'Odd number of input'
        Else
            'Total number-1 divided by 2 is even'
            If (sortedInput.Length - 1) Mod 4 = 0 Then
                position = 3 * (sortedInput.Length - 1) / 4
                num1 = sortedInput(position)
                num2 = sortedInput(position + 1)
                thirdQ = (num1 + num2) / 2
            'Total number-1 divided by 2 is odd'
            Else
                position = (3 * (sortedInput.Length) / 4)
                thirdQ = sortedInput(position)
            End If
        End If

        Return thirdQ
    End Function

    Function CalculateVariance() As Double
        Dim sumOfDeviation As Double = 0.0
        Dim variance As Double = 0.0

        'sum of (each number - mean)^2'
        For i As Integer = 0 To NumericalStatistic.ValueTextBox.Lines.Length - 1
            sumOfDeviation += (NumericalStatistic.ValueTextBox.Lines(i) - CalculateMean()) ^ 2
        Next

        variance = sumOfDeviation / NumericalStatistic.ValueTextBox.Lines.Length

        Return variance
    End Function

    Function SortArray() As Array
        Dim sortedArray(NumericalStatistic.ValueTextBox.Lines.Length - 1) As Double
        Dim num As Double
        'put the numbers into a Double data type array'
        For i As Integer = 0 To NumericalStatistic.ValueTextBox.Lines.Length - 1
            num = NumericalStatistic.ValueTextBox.Lines(i)
            sortedArray(i) = num
        Next

        Array.Sort(sortedArray)

        Return sortedArray
    End Function
End Class