How To Calculate Bollinger Bands in VB.NET?

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Imports System
Imports System.Collections.Generic
Imports System.Linq

Public Class BollingerBandsCalculator
    Private prices As List(Of Double)
    Private period As Integer
    Private k As Double

    Public Sub New(prices As List(Of Double), period As Integer, k As Double)
        Me.prices = prices
        Me.period = period
        Me.k = k
    End Sub

    Public Function CalculateBollingerBands() As List(Of List(Of Double))
        Dim bands As New List(Of List(Of Double))

        For i As Integer = 0 To prices.Count - period
            Dim sma As Double = CalculateSMA(i)
            Dim standardDeviation As Double = CalculateStandardDeviation(i, sma)

            Dim upperBand As Double = sma + k * standardDeviation
            Dim lowerBand As Double = sma - k * standardDeviation

            bands.Add(New List(Of Double) From {upperBand, lowerBand})
        Next

        Return bands
    End Function

    Private Function CalculateSMA(index As Integer) As Double
        Return prices.GetRange(index, period).Average()
    End Function

    Private Function CalculateStandardDeviation(index As Integer, sma As Double) As Double
        Dim sum As Double = prices
                        .GetRange(index, period)
                        .Select(Function(price) Math.Pow(price - sma, 2))
                        .Sum()

        Return Math.Sqrt(sum / period)
    End Function
End Class