Random File: Program Code ( visual basic )

Computer Science(9608) notes and Resources

Imports System.IO

Module Module1

    Structure employeerecord

        <VBFixedString(15)> Dim firstname As String

        <VBFixedString(15)> Dim lastname As String

        <VBFixedString(15)> Dim title As String

    End Structure

    Dim employee As employeerecord

    Dim filenumber As Integer

    Dim lastrec As Integer

    Dim position As Integer

    Dim reclength As Long = Len(employee)

    Dim deleted As Boolean = False

    Function randomgetlastrecord() As Integer

        filenumber = FreeFile()

        FileOpen(filenumber, "d:/employee.txt", OpenMode.Random, , , reclength)

        Dim lastrecord As Long

        lastrecord = 1

        Do While Not (EOF(filenumber))

            FileGet(filenumber, employee, lastrecord)

            lastrecord = lastrecord + 1

        Loop

        FileClose(filenumber)

       Return lastrecord

    End Function

    Sub randominputintofile()

        Dim employeefirstname As String

        Dim employeelastname As String

        Dim employeetitle As String

        Dim i As Integer

        For i = 1 To 3

            lastrec = randomgetlastrecord()

            filenumber = FreeFile()

            FileOpen(filenumber, "d:/employee.txt", OpenMode.Random, , , reclength)

            Console.WriteLine("enter firstname")

            employeefirstname = Console.ReadLine()

            Console.WriteLine("enter lastname")

            employeelastname = Console.ReadLine()

            Console.WriteLine("enter title")

            employeetitle = Console.ReadLine()

            employee.firstname = employeefirstname

            employee.lastname = employeelastname

            employee.title = employeetitle

            FilePut(filenumber, employee, lastrec)

            FileClose(filenumber)

        Next

    End Sub

    Sub randomgetfromfile()

        filenumber = FreeFile()

        FileOpen(filenumber, "d:/employee.txt", OpenMode.Random, , , reclength)

        position = 1

        Do While Not EOF(filenumber)

            FileGet(filenumber, employee, position)

            Console.WriteLine(employee.firstname & " " & employee.lastname & " " & employee.title)

            position = position + 1

        Loop

        FileClose(filenumber)

    End Sub

    Sub randomsearchrecord()

        Dim sname As String

        Console.WriteLine("enter name to search")

        sname = Console.ReadLine()

        filenumber = FreeFile()

        Dim found As Boolean = False

        FileOpen(filenumber, "d:/employee.txt", OpenMode.Random, , , reclength)

        Do While Not EOF(filenumber) And found = False

            FileGet(filenumber, employee, )

            If (Trim(employee.firstname) = sname) Then

                position = Loc(filenumber)

                found = True

            End If

        Loop

        If found = True Then

            Console.WriteLine("record found at position " & position)

            deleted = True

        Else

            Console.WriteLine("no record exits ")

        End If

        FileClose(filenumber)

    End Sub

    Sub randomupdaterecord()

        randomsearchrecord()

        Console.WriteLine("required position is " & position)

        filenumber = FreeFile()

        FileOpen(filenumber, "d:/employee.txt", OpenMode.Random, , , reclength)

        Seek(filenumber, position)

        employee.lastname = "dangol"

        employee.title = "lecturer"

        FilePut(filenumber, employee, )

        FileClose(filenumber)

    End Sub

    Sub randomdeleterecord()

        randomsearchrecord()

        Dim filenumber1, filenumber2 As Integer

        filenumber1 = FreeFile()

        FileOpen(filenumber1, "d:/employee.txt", OpenMode.Random, , , reclength)

        filenumber2 = FreeFile()

        FileOpen(filenumber2, "d:/employeenew.txt", OpenMode.Random, , , reclength)

        Do While Not EOF(filenumber1)

            If (Loc(filenumber1) <> position - 1) Then

                FileGet(filenumber1, employee, )

                FilePut(filenumber2, employee, )

            Else

                FileGet(filenumber1, employee, )

            End If

        Loop

        FileClose(filenumber1)

        FileClose(filenumber2)

        Kill("d:/employee.txt")

        Rename("d:/employeenew.txt", "d:/employee.txt")

        If deleted = True Then

            Console.WriteLine("Record deleted successfully")

        End If

    End Sub

    Sub Main()

        Console.WriteLine("Random file handling")

        Console.WriteLine("")

        Console.WriteLine("enter 1 to add record")

        Console.WriteLine("")

        Console.WriteLine("enter 2 to list record")

        Console.WriteLine("")

        Console.WriteLine("enter 3 to search record")

        Console.WriteLine("")

        Console.WriteLine("enter 4 to edit record")

        Console.WriteLine("")

        Console.WriteLine("enter 5 to delete record")

        Console.WriteLine("")

        Dim choice As Integer

        Console.WriteLine("ENTER YOUR CHOICE")

        choice = Console.ReadLine()

        Select Case choice

            Case 1

                randominputintofile()

            Case 2

                randomgetfromfile()

            Case 3

                randomsearchrecord()

            Case 4

                randomupdaterecord()

            Case 5

                randomdeleterecord()

            Case Else

                Console.WriteLine("invalid entry")

        End Select

        Console.ReadLine()

     End Sub

End Module

                                                           - CIE A-LEVEL COMPUTER SCIENCE (  9608 )