Public Class Form1
    Private Sub Form1_Load(...) Handles MyBase.Load
        lstLand.Items.Add("Liechtenstein")
        lstLand.Items.Add("Malta")
        lstLand.Items.Add("Andorra")
        lstLand.Items.Add("San Marino")
        lstLand.Items.Add("Monaco")
    End Sub

    Private Sub lstLand_SelectedIndexChanged(...
            ) Handles lstLand.SelectedIndexChanged
        If lstLand.SelectedItems.Count > 0 Then
            cmdLöschen.Enabled = True
        Else
            cmdLöschen.Enabled = False
        End If
    End Sub

    Private Sub cmdLöschen_Click(...) Handles ...
        lstLand.Items.RemoveAt(lstLand.SelectedIndex)
    End Sub
End Class

Public Class Form1
    Private Sub Form1_Load(...) Handles MyBase.Load
        Randomize()
    End Sub

    Private Sub cmdMinima_Click(...) Handles ...
        Dim T(9) As Integer
        Dim MinWert As Integer
        Dim i As Integer

        ' Feld füllen
        lstZahl.Items.Clear()
        For i = 0 To 9
            T(i) = Rnd() * 10 + 20
            lstZahl.Items.Add(T(i))
        Next i

        MinWert = T(0)
        For i = 0 To 9
            If T(i) < MinWert Then
                MinWert = T(i)
            End If
        Next i

        lblA.Text = "Minimum: " & MinWert &
            ", an Position:" & vbCrLf
        For i = 0 To 9
            If T(i) = MinWert Then
                lblA.Text &= i & vbCrLf
            End If
        Next i
    End Sub
End Class

Public Class Form1
    Private Sub Form1_Load(...) Handles MyBase.Load
        Randomize()
    End Sub

    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim T(5, 2, 3) As Integer
        Dim i, j, k As Integer
        Dim MinWert As Integer

        lblFeld.Text = ""
        For i = 0 To 5
            For j = 0 To 2
                lblFeld.Text &= "( "
                For k = 0 To 3
                    T(i, j, k) = Rnd() * 10 + 20
                    lblFeld.Text &= T(i, j, k) & " "
                Next k
                lblFeld.Text &= ") "
            Next j
            lblFeld.Text &= vbCrLf
        Next i

        MinWert = T(0, 0, 0)
        For i = 0 To 5
            For j = 0 To 2
                For k = 0 To 3
                    If T(i, j, k) < MinWert Then
                        MinWert = T(i, j, k)
                    End If
                Next k
            Next j
        Next i

        lblA.Text = "Minimum: " & MinWert &
            ", an Position:" & vbCrLf
        For i = 0 To 5
            For j = 0 To 2
                For k = 0 To 3
                    If T(i, j, k) = MinWert Then
                        lblA.Text &= "Zeile " & i &
                            ", Gruppe " & j &
                            ", Element " & k & vbCrLf
                    End If
                Next k
            Next j
        Next i
    End Sub
End Class

Public Class Form1
    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim x, y As Double
        x = 5.6
        y = 3.0
        mittelwert(x, y)
    End Sub

    Sub mittelwert(a As Double, b As Double)
        Dim c As Double
        c = (a + b) / 2
        lblA.Text = c
    End Sub
End Class

Public Class Form1
    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim x, y As Double
        x = 5.6
        y = 3.0
        lblA.Text = mittelwert(x, y)
    End Sub

    Function mittelwert(a As Double, b As Double) As Double
        mittelwert = (a + b) / 2
    End Function
End Class