Imports System
Class DigitFinder
Public Shared Function FindPreviousDigit(ByVal number As Integer, ByVal target As Integer) As Integer
While number > 0
Dim current As Integer = number Mod 10
number = number \ 10
If current = target Then
Return If(number > 0, number Mod 10, -1)
End If
End While
Return -1
End Function
Public Shared Sub Main()
Dim number As Integer = 8902741
Dim target As Integer = 7
Dim result As Integer = FindPreviousDigit(number, target)
If result <> -1 Then
Console.WriteLine($"The digit before {target} in {number} is {result}.")
Else
Console.WriteLine($"The digit {target} is not found or has no previous digit in {number}.")
End If
End Sub
End Class
' run:
'
' The digit before 7 in 8902741 is 2.
'
