Imports System

Public Module Module1

    Public Sub Main()

        Initialize()

        Dim Choice As Integer = 0

        While Choice <> 4

            Console.WriteLine("1 - Insert New Record")

            Console.WriteLine("2 - Search For A Node")

            Console.WriteLine("3 - Print")

            Console.WriteLine("4 - Exit")

            Choice = Console.ReadLine

            Select Case Choice

                Case 1 'insert

                    Console.WriteLine("Input the number you want to insert")

                    Dim NewItem As Integer

                    NewItem = Console.ReadLine()

                    Insert(NewItem)

                Case 2 'Search  

                    Console.WriteLine("Input the number you want to search for")

                    Dim SearchItem As Integer

                    SearchItem = Console.ReadLine()

                    Console.WriteLine(FindRecord(SearchItem))

                Case 3 'Print 

                    For i = 0 To n - 1

                        Console.WriteLine(i &"  " & HashTable(i))

                    Next

            End Select

        End While

    End Sub

    Dim n As Integer = 5

    Dim HashTable(n) As Integer

    Const NULLPOINTER As Integer = -1

    Sub Initialize()

        For i = 0 To n-1

            HashTable(i) = NULLPOINTER

        Next

    End Sub

    Function Hash(key) As Integer

        Dim Address As Integer

        Address = key MOD (n+1)

        Return Address

    End Function

    Sub Insert(NewRecord)

        Dim Index As Integer

        Index = Hash(NewRecord)

        While HashTable(Index) <> NULLPOINTER

            Index += 1

            If Index >= n Then

                Index = 0

            End If

        End While

        HashTable(Index) = NewRecord

    End Sub

    Function FindRecord(SearchKey) As Integer

        Dim Index As Integer

        Index = Hash(SearchKey)

        While HashTable(Index) <> SearchKey AND HashTable(Index) <> NULLPOINTER

            Index += 1

            If Index >= n Then

                Index = 0

            End If

        End While

        If HashTable(Index) <> NULLPOINTER Then

            Return Index

        Else

            Return -1

        End If

    End Function

End Module