Imports System
Class Program
    Private Shared Function VerifyAllUpperOrAllLowerOrIsCapitalized(ByVal word As String) As Boolean
        Dim upper As Integer = 0
        Dim lower As Integer = 0
        For Each ch As Char In word
            If Char.IsLower(ch) Then
                lower += 1
            ElseIf Char.IsUpper(ch) Then
                upper += 1
            End If
        Next
        If upper = 0 Then Return True
        If lower = 0 Then Return True
        If upper = 1 AndAlso Char.IsUpper(word(0)) Then Return True
        Return False
    End Function
    Private Shared Sub RunTest(ByVal word As String)
        Console.WriteLine("Testing word: " & word)
        If VerifyAllUpperOrAllLowerOrIsCapitalized(word) Then
            Console.WriteLine("OK" & vbLf)
        Else
            Console.WriteLine("Error" & vbLf)
        End If
    End Sub
    Public Shared Sub Main()
        RunTest("PROGRAMMING")
        RunTest("programming")
        RunTest("Programming")
        RunTest("ProGramMing")
    End Sub
End Class
' run:
'
' Testing word: PROGRAMMING
' OK
'
' Testing word: programming
' OK
'
' Testing word: Programming
' OK
'
' Testing word: ProGramMing
' Error
'