Public Class Form1
    'Private rain() As Integer = {7, 8, 0, 4, 3, 8, 1}
    Private rain(6) As Integer
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        rain(0) = 7
        rain(1) = 8
        rain(2) = 0
        rain(3) = 4
        rain(4) = 3
        rain(5) = 8
        rain(6) = 1

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim index, value As Integer
        index = CInt(TextBox1.Text)
        value = CInt(TextBox2.Text)
        rain(index) = value
        Display()
    End Sub

    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged

    End Sub

    Private Sub TextBox2_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox2.TextChanged

    End Sub

    Private Sub TextBox3_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox3.TextChanged

    End Sub

    Private Sub Label1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label1.Click

    End Sub

    Private Sub Label2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label2.Click

    End Sub

    Private Sub Display()
        Dim dn As Integer
        TextBox3.Text = Nothing
        For dn = 0 To 6
            TextBox3.Text = TextBox3.Text & "day " & CStr(dn) & " rain " & CStr(rain(dn)) & vbCrLf
        Next
        largest()
    End Sub

    Private Sub largest()
        Dim max As Integer = 0
        Dim maxind As Integer = 0
        Dim i As Integer
        For i = 0 To 6
            If rain(i) > max Then
                max = rain(i)
                maxind = i
            End If
        Next
        Label2.Text = "largest value is " & CStr(max) & " at " & CStr(maxind)
    End Sub
End Class