Visual Basic .NET: Spickzettel

Gut lesbare Sprache für .NET mit Wurzeln in BASIC

Ausführen: Datei Program.vb in einem Projekt (dotnet new console -lang VB) speichern und mit dotnet run ausführen (.NET SDK von dotnet.microsoft.com).

dotnet new console -lang VB -o hallo    # Projekt anlegen
cd hallo && dotnet run                  # bauen und starten
dotnet build                            # nur bauen
dotnet add package Newtonsoft.Json      # NuGet-Paket

Module Program
    Function Vorzeichen(n As Integer) As String
        If n > 0 Then
            Return "positiv"
        ElseIf n < 0 Then
            Return "negativ"
        Else
            Return "null"
        End If
    End Function

    Sub Main()
        Console.WriteLine(Vorzeichen(5) & " " & Vorzeichen(-2) & " " & Vorzeichen(0))

        Dim n As Integer = 15
        If n Mod 15 = 0 Then
            Console.WriteLine("FizzBuzz")
        ElseIf n Mod 3 = 0 Then
            Console.WriteLine("Fizz")
        Else
            Console.WriteLine(n)
        End If

        Dim note As Integer = 2
        Select Case note
            Case 1
                Console.WriteLine("sehr gut")
            Case 2, 3
                Console.WriteLine("gut bis befriedigend")
            Case 4 To 5
                Console.WriteLine("ausreichend bis mangelhaft")
            Case Is > 5
                Console.WriteLine("ungültig")
            Case Else
                Console.WriteLine("unbekannt")
        End Select

        Dim status As String = If(n > 10, "groß", "klein")
        Console.WriteLine(status)
        Console.WriteLine(If(Nothing, "Standardwert"))
        Console.WriteLine(n > 3 AndAlso n < 20)
        Console.WriteLine(n < 3 OrElse n = 15)
        Console.WriteLine(Not (n = 15))
    End Sub
End Module

Imports System.Collections.Generic

Module Program
    Sub Main()
        Dim a As Integer() = {5, 3, 9, 1, 7}
        Console.WriteLine(a.Length & " " & a(0) & " " & a(a.Length - 1))
        a(0) = 50
        Array.Sort(a)
        Console.WriteLine(String.Join(", ", a))
        Array.Reverse(a)
        Console.WriteLine(String.Join(", ", a))
        Dim m(1, 2) As Integer
        m(1, 2) = 7
        Console.WriteLine(m(1, 2) & " " & m.GetLength(0) & "x" & m.GetLength(1))

        Dim l As New List(Of Integer) From {5, 3, 9}
        l.Add(1)
        l.Insert(0, 100)
        l.Remove(3)
        Console.WriteLine(String.Join(", ", l))
        Console.WriteLine(l.Count & " " & l.Contains(9) & " " & l.IndexOf(9))
        l.Sort()
        Console.WriteLine(String.Join(", ", l))
        l.Reverse()
        Console.WriteLine(String.Join(", ", l))
        For Each x In l
            Console.Write(x & " ")
        Next
        Console.WriteLine()

        Dim zahlen = Enumerable.Range(1, 5).ToList()
        Console.WriteLine(String.Join(" ", zahlen))
        ReDim Preserve a(7)
        Console.WriteLine(a.Length)
    End Sub
End Module

Public Class Person
    Public Property Name As String
    Public Property Alter As Integer
    Private _geheim As Integer = 42

    Public Sub New(name As String, alter As Integer)
        Me.Name = name
        Me.Alter = alter
    End Sub

    Public Function IstVolljaehrig() As Boolean
        Return Alter >= 18
    End Function

    Public Overrides Function ToString() As String
        Return $"{Name} ({Alter})"
    End Function

    Public Shared Function Kind(name As String) As Person
        Return New Person(name, 5)
    End Function
End Class

Module Program
    Sub Main()
        Dim p As New Person("Mia", 17)
        Console.WriteLine(p)
        p.Alter = 18
        Console.WriteLine(p.IstVolljaehrig())
        Console.WriteLine(Person.Kind("Ben"))
        Dim q = New Person("Tom", 25) With {.Alter = 26}
        Console.WriteLine(q)
        Console.WriteLine(p Is q)
        Console.WriteLine(p.Equals(p))
    End Sub
End Module

Imports System.Text

Module Program
    Sub Main()
        Dim s As String = "Hallo VB.NET-Welt"
        Console.WriteLine(s.Length & " " & s.ToUpper() & " " & s.ToLower())
        Console.WriteLine(s(0) & " " & s.Substring(6, 2) & " " & s.Substring(6))
        Console.WriteLine(s.Replace("Welt", "Erde"))
        Console.WriteLine(String.Join("|", s.Split(" "c, "-"c)))
        Console.WriteLine(s.Contains("VB") & " " & s.StartsWith("Hallo") & " " & s.EndsWith("x"))
        Console.WriteLine(s.IndexOf("VB") & " " & s.LastIndexOf("l"))
        Console.WriteLine("[" & "  trim  ".Trim() & "]")
        Console.WriteLine(New String("*"c, 5) & " " & "ab".PadLeft(5, "_"c) & " " & "ab".PadRight(5, "_"c))
        Console.WriteLine(String.Format("{0,-6}|{1,6}|{2:F2}|{3:X}", "li", "re", Math.PI, 255))
        Console.WriteLine($"{42:D5} {1234567:N0} {0.256:P1}")
        Console.WriteLine(CInt("17") + 1)
        Dim zahl As Integer
        Console.WriteLine(Integer.TryParse("abc", zahl) & " " & Integer.TryParse("42", zahl) & " " & zahl)
        Console.WriteLine(Asc("A") & " " & Chr(66) & " " & AscW("a"c))
        Console.WriteLine(StrReverse("Basic"))
        Console.WriteLine(UCase("x") & LCase("Y"))
        Console.WriteLine(Left("Visual", 3) & " " & Right("Visual", 3) & " " & Mid("Visual", 2, 3))
        Console.WriteLine("abc" < "abd")
        Console.WriteLine("Apfel".CompareTo("Birne"))
        Console.WriteLine(String.Equals("a", "A", StringComparison.OrdinalIgnoreCase))
        Dim sb As New StringBuilder()
        For i As Integer = 1 To 5
            sb.Append(i).Append(","c)
        Next
        Console.WriteLine(sb.ToString().TrimEnd(","c))
        Console.WriteLine("Zeile1" & vbCrLf & "Zeile2" & vbTab & "Tab")
    End Sub
End Module

Public Class Kiste(Of T)
    Public Property Inhalt As T
    Public Sub New(inhalt As T)
        Me.Inhalt = inhalt
    End Sub
    Public Function Zeige() As String
        Return $"Kiste mit {Inhalt}"
    End Function
End Class

Module Program
    Function Groesster(Of T As IComparable(Of T))(liste As T()) As T
        Dim m As T = liste(0)
        For Each x In liste
            If x.CompareTo(m) > 0 Then m = x
        Next
        Return m
    End Function

    Sub Tausche(Of T)(ByRef a As T, ByRef b As T)
        Dim tmp As T = a
        a = b
        b = tmp
    End Sub

    Sub Main()
        Console.WriteLine(New Kiste(Of Integer)(42).Zeige())
        Console.WriteLine(New Kiste(Of String)("Text").Zeige())
        Console.WriteLine(Groesster({3, 9, 4}))
        Console.WriteLine(Groesster({"b", "z", "a"}))
        Dim a As String = "x", b As String = "y"
        Tausche(a, b)
        Console.WriteLine(a & b)
    End Sub
End Module

Module Program
    Function Sieb(n As Integer) As List(Of Integer)
        Dim prim(n) As Boolean
        For i As Integer = 2 To n
            prim(i) = True
        Next
        For i As Integer = 2 To CInt(Math.Sqrt(n))
            If prim(i) Then
                For j As Integer = i * i To n Step i
                    prim(j) = False
                Next
            End If
        Next
        Dim erg As New List(Of Integer)
        For i As Integer = 2 To n
            If prim(i) Then erg.Add(i)
        Next
        Return erg
    End Function

    Sub Main()
        Console.WriteLine(String.Join(" ", Sieb(50)))
        Console.WriteLine(Sieb(10000).Count)
    End Sub
End Module

Module Program
    Sub Zeile(name As String, wert As Object)
        Console.WriteLine(name.PadRight(22) & wert.ToString())
    End Sub

    Sub Main()
        Zeile("CInt(3.5)", CInt(3.5))
        Zeile("CInt(2.5)", CInt(2.5))
        Zeile("CDbl(""2.5"") + 1", CDbl("2.5") + 1)
        Zeile("CBool(0)", CBool(0))
        Zeile("CStr(True)", CStr(True))
        Zeile("TypeName(1)", TypeName(1))
        Zeile("IsNumeric(""12"")", IsNumeric("12"))
        Zeile("IsNumeric(""x"")", IsNumeric("x"))
        Zeile("Format(1234.5, ""N1"")", Format(1234.5, "N1"))
        Zeile("Int(-2.5)", Int(-2.5))
        Zeile("Fix(-2.5)", Fix(-2.5))
        Zeile("Math.Sign(-9)", Math.Sign(-9))
        Zeile("Len(""abc"")", Len("abc"))
        Zeile("InStr(""abc"", ""c"")", InStr("abc", "c"))
        Zeile("Replace(""aXa"", ""X"", ""-"")", Replace("aXa", "X", "-"))
        Zeile("Nothing Is Nothing", Nothing Is Nothing)
        Zeile("5 Mod 3", 5 Mod 3)
        Zeile("-5 \ 2", -5 \ 2)
        Zeile("If(True, 1, 2)", If(True, 1, 2))
    End Sub
End Module