B.3 Lösungen der Übungsaufgaben aus Kapitel 4
B.3.1 Lösung ÜEnabled
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
B.3.2 Lösung ÜDatenfeldEindimensional
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
B.3.3 Lösung ÜDatenfeldMehrdimensional
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
B.3.4 Lösung ÜProzeduren
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
B.3.5 Lösung ÜFunktionen
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
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