Function IsAlphabetic Learn programming Visual Basic (VB.net)

Lesson:

Functions

Exercise:

Function IsAlphabetic

Objetive:

Create a function that tells if a character is alphabetic (A through Z) or not. It should be used like this:

if (IsAlphabetic ("a"))
System.Console.WriteLine ("It is an alphabetic character");

(Note: do not worry about accents and ñ)

Code:

Imports System
Public Class exercise123
    Public Shared Function IsAlpha(ByVal simbolo As Char) As Boolean
        If (simbolo >= "a"c) AndAlso (simbolo <= "z"c) Then Return True
        If (simbolo >= "A"c) AndAlso (simbolo <= "Z"c) Then Return True
        Return False
    End Function

Public Shared Function IsAlpha2(ByVal simbolo As Char) As Boolean
        simbolo = Char.ToLower(simbolo)
        If (simbolo >= "a"c) AndAlso (simbolo <= "z"c) Then Return True
        Return False
    End Function

Public Shared Function IsAlpha3(ByVal simbolo As Char) As Boolean
        simbolo = simbolo.ToString().ToLower()(0)
        If (simbolo >= "a"c) AndAlso (simbolo <= "z"c) Then Return True
        Return False
    End Function

Public Shared Function IsAlpha4(ByVal simbolo As Char) As Boolean
        Dim validas As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqwrstuvwxyz"
        If validas.Contains(simbolo) Then Return True
        Return False
    End Function

Public Shared Sub Main()
        Console.WriteLine(IsAlpha("w"c))
        Console.WriteLine(IsAlpha("2"c))
    End Sub
End Class

Imports System
Public Class exercise123
    Public Shared Function IsAlpha(ByVal simbolo As Char) As Boolean
        If (simbolo >= "a"c) AndAlso (simbolo <= "z"c) Then Return True
        If (simbolo >= "A"c) AndAlso (simbolo <= "Z"c) Then Return True
        Return False
    End Function

    Public Shared Function IsAlpha2(ByVal simbolo As Char) As Boolean
        simbolo = Char.ToLower(simbolo)
        If (simbolo >= "a"c) AndAlso (simbolo <= "z"c) Then Return True
        Return False
    End Function

    Public Shared Function IsAlpha3(ByVal simbolo As Char) As Boolean
        simbolo = simbolo.ToString().ToLower()(0)
        If (simbolo >= "a"c) AndAlso (simbolo <= "z"c) Then Return True
        Return False
    End Function

    Public Shared Function IsAlpha4(ByVal simbolo As Char) As Boolean
        Dim validas As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqwrstuvwxyz"
        If validas.Contains(simbolo) Then Return True
        Return False
    End Function

    Public Shared Sub Main()
        Console.WriteLine(IsAlpha("w"c))
        Console.WriteLine(IsAlpha("2"c))
    End Sub
End Class