Option Strict On
Option Explicit On
Public Class frmMain

    Private Sub btnDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplay.Click
        'initial population is 300000 and population growth rate is 3%
        Dim population As Double = 300000
        Dim growthRate As Double = 0.03

        'Loops from the begining year to end year (NO VALIDATION ON THE END YEAR)
        For yr As Integer = CInt(txtStart.Text) To CInt(txtEnd.Text)
            'Adds an item to the list for the year and the adjusted population
            lstPopulation.Items.Add(CStr(yr) & "     " & FormatNumber(population, 0))
            'population grows but the growthRate times the current population
            population += population * growthRate
        Next
    End Sub
End Class