Public Class Form1
    Dim teller As Integer 'utenfor, så slipper du å ta den med to ganger
    Dim vare(4) As String
    Dim pris(4) As Integer
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        For teller = 0 To 4
            vare(teller) = InputBox("Skriv inn vare")
        Next teller

        For Each enVare In vare
            ListBox1.Items.Add(enVare)
        Next
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        For teller = 0 To 4
            pris(teller) = InputBox("Skriv inn pris")
        Next teller

        For Each enPris In pris
            ListBox2.Items.Add(enPris & " kr")
        Next

        ListBox3.Items.Add("Summen av varene er " & pris.Sum & " kr")
        ListBox3.Items.Add("Gjennomsnittet av varene er " & pris.Average & " kr")
        ListBox3.Items.Add("Høyeste pris er " & pris.Max & " kr")
        ListBox3.Items.Add("Laveste pris er" & pris.Min & " kr")
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        Dim output = ""
        For indeks = 0 To pris.Length - 1
            If TextBox1.Text = vare(indeks) Then
                output = vare(indeks) & " koster " & pris(indeks) & " kroner."
                ListBox4.Items.Add(output)
            End If
        Next

        If output = "" Then
            MsgBox("Matvaren finnes ikke")
        End If
    End Sub
End Class