Rheinwerk Computing :: Einstieg in Visual Basic 2012

B.2 Lösungen der Übungsaufgaben aus Kapitel 2

B.2.1 Lösung ÜDatentypen

Public Class Form1
    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim nachname, vorname As String
        Dim strasse, plz, ort As String
        Dim alter As Integer
        Dim geburtsdatum As Date

        nachname = "Basic"
        vorname = "Bodo"
        strasse = "Bergstraße 34"
        plz = "09445"
        ort = "Brunnstadt"
        alter = 32
        geburtsdatum = "18.05.1985"

        lblA.Text = "Adresse: " & vbCrLf & vorname &
            " " & nachname & vbCrLf & strasse &
            vbCrLf & plz & " " & ort & vbCrLf &
            vbCrLf & "geb.: " & geburtsdatum &
            vbCrLf & "Alter: " & alter
    End Sub
End Class

B.2.2 Lösung ÜGültigkeitsbereich

Public Class Form1
    Dim x As Double

    Private Sub cmdAnzeigen1_Click(sender As Object,
            e As EventArgs) Handles cmdAnzeigen1.Click
        Dim y As Double
        y = y + 0.1
        x = x + 0.1
        lblA.Text = "x: " & x & vbCrLf & "y: " & y
    End Sub

    Private Sub cmdAnzeigen2_Click(sender As Object,
            e As EventArgs) Handles cmdAnzeigen2.Click
        Dim z As Double
        z = z + 0.1
        x = x + 0.1
        lblA.Text = "x: " & x & vbCrLf & "z: " & z
    End Sub
End Class

B.2.3 Lösung ÜRechenoperatoren

Public Class Form1
    Private Sub cmdAnzeigen1_Click(...) Handles ...
        Dim x As Double
        x = 3 * –2.5 + 4 * 2
        lblA.Text = x
    End Sub

    Private Sub cmdAnzeigen2_Click(...) Handles ...
        Dim x As Double
        x = 3 * (-2.5 + 4) * 2
        lblA.Text = x
    End Sub
End Class

B.2.4 Lösung ÜVergleichsoperatoren

Public Class Form1
    Private Sub cmdAnzeigen1_Click(...) Handles ...
        Dim p As Boolean
        p = 12 – 3 >= 4 * 2.5
        lblA.Text = p
    End Sub

    Private Sub cmdAnzeigen2_Click(...) Handles ...
        Dim p As Boolean
        p = "Maier" Like "M??er"
        lblA.Text = p
    End Sub
End Class

B.2.5 Lösung ÜLogischeOperatoren

Public Class Form1
    Private Sub cmdAnzeigen1_Click(...) Handles ...
        Dim p As Boolean
        p = 4 > 3 And –4 > –3
        lblA.Text = p
    End Sub

    Private Sub cmdAnzeigen2_Click(...) Handles ...
        Dim p As Boolean
        p = 4 > 3 Or –4 > –3
        lblA.Text = p
    End Sub
End Class

B.2.6 Lösung ÜOperatoren

1: False, 2: True, 3: True, 4: True, 5: True, 6: False, 7: True, 8: False

B.2.7 Lösung ÜPanelZeitgeber

Public Class Form1
    Private Sub cmdStart_Click(...) Handles ...
        tim1.Enabled = True
    End Sub

    Private Sub tim1_Tick(...
            ) Handles tim1.Tick
        pan1.Location = New Point(
            pan1.Location.X – 5, pan1.Location.Y – 5)
        pan2.Location = New Point(
            pan2.Location.X + 5, pan2.Location.Y – 5)
        pan3.Location = New Point(
            pan3.Location.X – 5, pan3.Location.Y + 5)
        pan4.Location = New Point(
            pan4.Location.X + 5, pan4.Location.Y + 5)
    End Sub
End Class

B.2.8 Lösung ÜKran

Bezeichnungen:

f: Fundament
s: senkrechtes Hauptelement
a: waagerechter Ausleger
h: senkrechter Haken am Ausleger

Public Class Form1
    Private Sub cmdHakenAus_Click(...) Handles ...
        h.Height = h.Height + 10
    End Sub

    Private Sub cmdHakenEin_Click(...) Handles ...
        h.Height = h.Height – 10
    End Sub

    Private Sub cmdAuslegerAus_Click(...) Handles ...
        a.Width = a.Width + 10
        a.Location = New Point(
            a.Location.X – 10, a.Location.Y)
        h.Location = New Point(
            h.Location.X – 10, h.Location.Y)
    End Sub

    Private Sub cmdAuslegerEin_Click(...) Handles ...
        a.Width = a.Width – 10
        a.Location = New Point(
            a.Location.X + 10, a.Location.Y)
        h.Location = New Point(
            h.Location.X + 10, h.Location.Y)
    End Sub

    Private Sub cmdKranRechts_Click(...) Handles ...
        f.Location = New Point(
            f.Location.X + 10, f.Location.Y)
        s.Location = New Point(
            s.Location.X + 10, s.Location.Y)
        a.Location = New Point(
            a.Location.X + 10, a.Location.Y)
        h.Location = New Point(
            h.Location.X + 10, h.Location.Y)
    End Sub

    Private Sub cmdKranLinks_Click(...) Handles ...
        f.Location = New Point(
            f.Location.X – 10, f.Location.Y)
        s.Location = New Point(
            s.Location.X – 10, s.Location.Y)
        a.Location = New Point(
            a.Location.X – 10, a.Location.Y)
        h.Location = New Point(
            h.Location.X – 10, h.Location.Y)
    End Sub

    Private Sub cmdKranAus_Click(...) Handles ...
        s.Height = s.Height + 10
        s.Location = New Point(
            s.Location.X, s.Location.Y – 10)
        a.Location = New Point(
            a.Location.X, a.Location.Y – 10)
        h.Location = New Point(
            h.Location.X, h.Location.Y – 10)
    End Sub

    Private Sub cmdKranEin_Click(...) Handles ...
        s.Height = s.Height – 10
        s.Location = New Point(
            s.Location.X, s.Location.Y + 10)
        a.Location = New Point(
            a.Location.X, a.Location.Y + 10)
        h.Location = New Point(
            h.Location.X, h.Location.Y + 10)
    End Sub
End Class

B.2.9 Lösung ÜSteuerbetrag, zwei Alternativen

Public Class Form1
    Private Sub cmdBerechnen1_Click(...) Handles ...
        Dim gehalt, steuersatz, steuerbetrag As Double

        gehalt = Convert.ToDouble(txtGehalt.Text)

        If gehalt <= 12000 Then
            steuersatz = 12
        ElseIf gehalt <= 20000 Then
            steuersatz = 15
        ElseIf gehalt <= 30000 Then
            steuersatz = 20
        Else
            steuersatz = 25
        End If

        steuerbetrag = gehalt * steuersatz / 100
        lblSteuerbetrag.Text = steuerbetrag
    End Sub

    Private Sub cmdBerechnen2_Click(...) Handles ...
        Dim gehalt, steuersatz, steuerbetrag As Double

        gehalt = Convert.ToDouble(txtGehalt.Text)

        Select Case gehalt
            Case Is <= 12000
                steuersatz = 12
            Case Is <= 20000
                steuersatz = 15
            Case Is <= 30000
                steuersatz = 20
            Case Else
                steuersatz = 25
        End Select

        steuerbetrag = gehalt * steuersatz / 100
        lblSteuerbetrag.Text = steuerbetrag
    End Sub
End Class

B.2.10 Lösung ÜKranVerzweigung

Bezeichnungen:

f: Fundament
s: senkrechtes Hauptelement
a: waagerechter Ausleger
h: senkrechter Haken am Ausleger

Public Class Form1
    Private Sub cmdHakenAus_Click(...) Handles ...
        If h.Location.Y + h.Height + 5 <
                f.Location.Y Then
            h.Height = h.Height + 10
        End If
    End Sub

    Private Sub cmdHakenEin_Click(...) Handles ...
        If h.Height > 15 Then
            h.Height = h.Height – 10
        End If
    End Sub

    Private Sub cmdAuslegerAus_Click(...) Handles ...
        If a.Location.X > 15 Then
            a.Width = a.Width + 10
            a.Location = New Point(
                a.Location.X – 10, a.Location.Y)
            h.Location = New Point(
                h.Location.X – 10, h.Location.Y)
        End If
    End Sub

    Private Sub cmdAuslegerEin_Click(...) Handles ...
        If a.Width > 30 Then
            a.Width = a.Width – 10
            a.Location = New Point(
                a.Location.X + 10, a.Location.Y)
            h.Location = New Point(
                h.Location.X + 10, h.Location.Y)
        End If
    End Sub

    Private Sub cmdKranRechts_Click(...) Handles ...
        If f.Location.X < 215 Then
            f.Location = New Point(
                f.Location.X + 10, f.Location.Y)
            s.Location = New Point(
                s.Location.X + 10, s.Location.Y)
            a.Location = New Point(
                a.Location.X + 10, a.Location.Y)
            h.Location = New Point(
                h.Location.X + 10, h.Location.Y)
        End If
    End Sub

    Private Sub cmdKranLinks_Click(...) Handles ...
        If f.Location.X > 15 And
                    a.Location.X > 15 Then
            f.Location = New Point(
                f.Location.X – 10, f.Location.Y)
            s.Location = New Point(
                s.Location.X – 10, s.Location.Y)
            a.Location = New Point(
                a.Location.X – 10, a.Location.Y)
            h.Location = New Point(
                h.Location.X – 10, h.Location.Y)
        End If
    End Sub

    Private Sub cmdKranAus_Click(...) Handles ...
        If s.Location.Y > 15 Then
            s.Height = s.Height + 10
            s.Location = New Point(
                s.Location.X, s.Location.Y – 10)
            a.Location = New Point(
                a.Location.X, a.Location.Y – 10)
            h.Location = New Point(
                h.Location.X, h.Location.Y – 10)
        End If
    End Sub

    Private Sub cmdKranEin_Click(...) Handles ...
        If h.Location.Y + h.Height + 5 <
                f.Location.Y Then
            s.Height = s.Height – 10
            s.Location = New Point(
                s.Location.X, s.Location.Y + 10)
            a.Location = New Point(
                a.Location.X, a.Location.Y + 10)
            h.Location = New Point(
                h.Location.X, h.Location.Y + 10)
        End If
    End Sub
End Class

B.2.11 Lösung ÜKranOptionen

Bezeichnungen:

f: Fundament
s: senkrechtes Hauptelement
a: waagerechter Ausleger
h: senkrechter Haken am Ausleger

Public Class Form1
    Private Sub cmdStart_Click(...) Handles ...
        tim1.Enabled = True
    End Sub

    Private Sub cmdStop_Click(...) Handles ...
        tim1.Enabled = False
    End Sub

    Private Sub tim1_Tick(...
            ) Handles tim1.Tick
        If optHakenAus.Checked Then
            If h.Location.Y + h.Height + 5 <
                    f.Location.Y Then
                h.Height = h.Height + 10
            Else
                tim1.Enabled = False
            End If
        ElseIf optHakenEin.Checked Then
            If h.Height > 15 Then
                h.Height = h.Height – 10
            Else
                tim1.Enabled = False
            End If
        ElseIf optAuslegerAus.Checked Then
            If a.Location.X > 15 Then
                a.Width = a.Width + 10
                a.Location = New Point(
                    a.Location.X – 10, a.Location.Y)
                h.Location = New Point(
                    h.Location.X – 10, h.Location.Y)
            Else
                tim1.Enabled = False
            End If
        ElseIf optAuslegerEin.Checked Then
            If a.Width > 25 Then
                a.Width = a.Width – 10
                a.Location = New Point(
                    a.Location.X + 10, a.Location.Y)
                h.Location = New Point(
                    h.Location.X + 10, h.Location.Y)
            Else
                tim1.Enabled = False
            End If
        ElseIf optKranRechts.Checked Then
            If f.Location.X < 215 Then
                f.Location = New Point(
                    f.Location.X + 10, f.Location.Y)
                s.Location = New Point(
                    s.Location.X + 10, s.Location.Y)
                a.Location = New Point(
                    a.Location.X + 10, a.Location.Y)
                h.Location = New Point(
                    h.Location.X + 10, h.Location.Y)
            Else
                tim1.Enabled = False
            End If
        ElseIf optKranLinks.Checked Then
            If f.Location.X > 15 And
                    a.Location.X > 15 Then
                f.Location = New Point(
                    f.Location.X – 10, f.Location.Y)
                s.Location = New Point(
                    s.Location.X – 10, s.Location.Y)
                a.Location = New Point(
                    a.Location.X – 10, a.Location.Y)
                h.Location = New Point(
                    h.Location.X – 10, h.Location.Y)
            Else
                tim1.Enabled = False
            End If
        ElseIf optKranAus.Checked Then
            If s.Location.Y > 15 Then
                s.Height = s.Height + 10
                s.Location = New Point(
                    s.Location.X, s.Location.Y – 10)
                a.Location = New Point(
                    a.Location.X, a.Location.Y – 10)
                h.Location = New Point(
                    h.Location.X, h.Location.Y – 10)
            Else
                tim1.Enabled = False
            End If
        ElseIf optKranEin.Checked Then
            If h.Location.Y + h.Height + 5 <
                    f.Location.Y Then
                s.Height = s.Height – 10
                s.Location = New Point(
                    s.Location.X, s.Location.Y + 10)
                a.Location = New Point(
                    a.Location.X, a.Location.Y + 10)
                h.Location = New Point(
                    h.Location.X, h.Location.Y + 10)
            Else
                tim1.Enabled = False
            End If
        End If
    End Sub
End Class

B.2.12 Lösung ÜForNext1

Public Class Form1
    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim d As Double
        For d = 35 To 20 Step –2.5
            lblA.Text &= d & vbCrLf
        Next
    End Sub
End Class

B.2.13 Lösung ÜForNext2

Public Class Form1
    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim d, summe, zähler, mittelwert As Double
        summe = 0
        zähler = 0

        For d = 35 To 20 Step –2.5
            lblA.Text &= d & vbCrLf
            summe += d
            zähler += 1
        Next

        mittelwert = summe / zähler
        lblA.Text &= vbCrLf &
            "Summe: " & summe & vbCrLf &
            "Mittelwert: " & mittelwert & vbCrLf
    End Sub
End Class

B.2.14 Lösung ÜDoLoop

Public Class Form1
    Private Sub cmdHalbieren_Click(...) Handles ...
        Dim d As Double
        d = Convert.ToDouble(txtEingabe.Text)

        lblA.Text = ""
        Do While d > 0.001
            d = d / 2
            lblA.Text &= d & vbCrLf
        Loop
    End Sub
End Class

B.2.15 Lösung ÜZahlenraten

Public Class Form1
    Dim zahl As Integer

    Private Sub Form1_Load(...) Handles MyBase.Load
        Randomize()
        zahl = Rnd() * 100 + 1
    End Sub

    Private Sub cmdPrüfen_Click(...) Handles ...
        Dim eingabe As Integer
        eingabe = Convert.ToDouble(txtEingabe.Text)

        If eingabe > zahl Then
            lblA.Text = "Die Zahl " & eingabe &
                " ist zu groß"
        ElseIf eingabe < zahl Then
            lblA.Text = "Die Zahl " & eingabe &
                " ist zu klein"
        Else
            lblA.Text = eingabe &
                " ist die richtige Zahl, gratuliere"
        End If
    End Sub
End Class

B.2.16 Lösung ÜSteuertabelle

Public Class Form1
    Private Sub cmdAnzeigen_Click(...) Handles ...
        Dim gehalt As Double
        Dim steuersatz As Double
        Dim steuerbetrag As Double
        Dim netto As Double

        For gehalt = 5000 To 35000 Step 3000
            If gehalt <= 12000 Then
                steuersatz = 12
            ElseIf gehalt <= 20000 Then
                steuersatz = 15
            ElseIf gehalt <= 30000 Then
                steuersatz = 20
            Else
                steuersatz = 25
            End If

            steuerbetrag = gehalt * steuersatz / 100
            netto = gehalt – steuerbetrag
            lblA.Text &= gehalt & " €, " &
                steuersatz & " %, " &
                steuerbetrag & " €, " &
                netto & " €" & vbCrLf
        Next
    End Sub
End Class

B.2.17 Lösung ÜListenfeld

Public Class Form1
    Private Sub Form1_Load(...) Handles MyBase.Load
        lstLinks.Items.Add("Malta")
        lstLinks.Items.Add("Zypern")
        lstLinks.Items.Add("Slowenien")
        lstLinks.Items.Add("Estland")
        lstLinks.Items.Add("Rumänien")

        lstRechts.Items.Add("Belgien")
        lstRechts.Items.Add("Spanien")
        lstRechts.Items.Add("Italien")
        lstRechts.Items.Add("Portugal")
        lstRechts.Items.Add("Dänemark")
    End Sub

    Private Sub cmdRechts_Click(...) Handles ...
        Dim i As Integer

        For i = 0 To lstLinks.SelectedItems.Count – 1
            lstRechts.Items.Add(
                lstLinks.SelectedItems(i))
        Next

        For i = lstLinks.SelectedItems.
                Count – 1 To 0 Step –1
            lstLinks.Items.RemoveAt(
                lstLinks.SelectedIndices(i))
        Next
    End Sub

    Private Sub cmdLinks_Click(...) Handles ...
        Dim i As Integer

        For i = 0 To lstRechts.SelectedItems.Count – 1
            lstLinks.Items.Add(
                lstRechts.SelectedItems(i))
        Next

        For i = lstRechts.SelectedItems.
                Count – 1 To 0 Step –1
            lstRechts.Items.RemoveAt(
                lstRechts.SelectedIndices(i))
        Next
    End Sub
End Class

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