I need to traverse through an 8 digit String to check some conditions in VB.Net

Question

I need help in Vb.net, how can I traverse through an 8 digit integer and check whether

1. Three numbers r repeated consecutively like 111,222
2. Check whether numbers are consecutively spaced like 123,876 3. Check whether 4 numbers r present

I input the 8 digit as string as its a requirement then convert into a string.

Imports System.console

Public Class residentNumberCheck

    Dim cardNumber As String

    Public Sub inputNumberAndCheck()

        writeline("Enter the 8 Digit Resident Card Number")
        cardNumber = readline()

        While (cardNumber.length() <> 8)
            writeline("The Resident Card Number is Invalid. It does not contain 8 digits... Please enter again")
            cardNumber = readline()
        End While

    End Sub

    Public Sub sameThreeNumber()

        writeline("")
        writeline("...Checking for 3 consecutive numbers...")
        writeline("")

        Dim Num As Integer = Integer.parse(cardNumber)
        Dim temp As Integer = Num


        Dim i As Integer
        Dim j As Integer
        Dim k As Integer
        Dim checker As Boolean = False

        While (Num > 0)

            i = Num Mod 10

            Num = Num \ 10

            j = Num Mod 10

            temp = temp \ 10

            k = temp Mod 10

            Num = temp \ 10

            temp = Num \ 10

            If (i = j And j = k) Then

                writeline("    ****The Number is a Special Number as the Number {0} occurs three consecutive times****", i)
                checker = True

                Return

            End If

        End While

        If (checker = False) Then
            writeline("The Number does not have 3 consecutive numbers")
        End If

    End Sub

    Public Sub ConsecutiveNumber()

        writeline("")
        writeline("...Checking for consecutive digits in increasing or decreasing...")
        writeline("")

        Dim Num As Integer = Integer.parse(cardNumber)
        Dim temp As Integer = Num


        Dim i As Integer
        Dim j As Integer
        Dim k As Integer
        Dim checker As Boolean = False

        While (Num > 0)

            i = Num Mod 10

            Num = Num \ 10

            j = Num Mod 10

            temp = temp \ 10

            k = temp Mod 10

            Num = temp \ 10

            temp = Num \ 10

check1:
            If (i = j + 1) Then
                If (j = k + 1) Then
                    checker = True
                    writeline("    ****The Number is a Special Number as it has {0}, {1}, {2} consecutive numbers****", k, j, i)
                    Return
                End If
            End If
check2:
            If (i = j - 1) Then
                If (j = k - 1) Then
                    checker = True
                    writeline("    ****The Number is a Special Number as it has {0}, {1}, {2} consecutive numbers****", k, j, i)
                    Return
                End If
            End If

        End While

        If (checker = False) Then
            writeline("The Number does not contain consecutive digits in increasing or decreasing")
        End If

    End Sub

    Public Sub checksimilarfourdigits()

        writeline("")
        writeline("...Checking if a number is repeated four times...")
        writeline("")

        Dim Num As Integer = Integer.parse(cardNumber)
        Dim temp As Integer
        Dim x As Integer
        Dim y As Integer

        Dim i As Integer
        Dim j As Integer
        Dim counter As Integer = 0
        Dim checker As Boolean = False

        While (Num > 0)

logic:

            i = Num Mod 10

            Num = Num \ 10

            j = Num Mod 10

            Num = Num \ 10

check:

            If (i = j) Then
                counter = counter + 1
                temp = i
            Else
                temp = j
                GoTo logic
            End If

            If (temp = i) Then
                counter = counter + 1
                x = temp
                y = 0
            End If

            If (temp = j) Then
                counter = counter + 1
                y = temp
                x = 0
            End If

            If (counter >= 4) Then

                If (x = 0) Then

                    writeline("    ****The Number is a Special Number as the number {0} repeats four times or more****", y)
                    checker = True
                    Return
                End If

                If (y = 0) Then
                    writeline("    ****The Number is a Special Number as the number {0} repeats four times or more****", x)
                    checker = True
                    Return
                End If

            End If

        End While

        If (checker = False) Then
            writeline("The Number does not contain 4 equal digits")
        End If


    End Sub

    Public Shared Sub main()
        Dim user As residentNumberCheck = New residentNumberCheck()
        user.inputNumberAndCheck()
        user.sameThreeNumber()
        user.ConsecutiveNumber()
        user.checksimilarfourdigits()

    End Sub

End Class

Answer 1

If you want to compact your code you may use Regex class:

        Dim cardNumber As String = TextBox1.Text
' (\d) finds digit (\d)\1 finds digit repeated once, here \1 makes
' reference to first group (), this is, (\d)
' (\d)\1{2,} finds digit repeated at least 2 times
        Dim mc As MatchCollection = New Regex("(\d)\1{2,}").Matches(cardNumber)
        If mc.Count Then ' there are at least 3 consecutive equal #s
            Trace.WriteLine(String.Format("Number {0} occurs {1} times", mc(0).Value, mc(0).Value.Length))
        End If
        mc = New Regex("\d").Matches(cardNumber)
        ' each mc() contains one digit
        Dim incr As Int32=0, indI As Int32 = -1
        Dim decr As Int32=0, indD As Int32 = -1
        For i As Int32 = 0 To mc.Count - 1
            Dim curr As Int32 = Int32.Parse(mc(i).Value)
            If i < mc.Count - 1 Then ' there is a next number
                ' if current+1=next# =>increment count & save index
                If curr + 1 = Int32.Parse(mc(i + 1).Value) Then
                    If indI = -1 Then indI = i
                    incr += 1 : If incr = 2 Then Exit For
                Else
                    incr = 0 : indI = -1
                End If
            End If
            If i Then ' there is a previous #
    ' if current+1=previous# =>previous incr. count & save index
                If curr + 1 = Int32.Parse(mc(i - 1).Value) Then
                    If indD = -1 Then indD = i
                    decr += 1 : If decr = 2 Then Exit For
                Else
                    decr = 0 : indD = -1
                End If
            End If
        Next
        If incr = 2 Then
            Trace.WriteLine(String.Format("{0}{1}{2} Consecutive numbers", mc(indI), mc(indI + 1), mc(indI + 2)))
        ElseIf decr = 2 Then
            Trace.WriteLine(String.Format("{0}{1}{2} Consecutive numbers", mc(indD - 1), mc(indD), mc(indD + 1)))
        End If