How to display random ques from text file in vb? - vb.net

Question

I have created a Quiz application in Visual Basic.I have stored the questions in a text file and I'm using streamreader to read the lines.The text file looks like this
If x is the first of five consecutive odd numbers then what is their average ?
x
x+1
x+4
x+3
3
Which of the following number is divisible by 24 ?
76300
78132
80424
81234
3
The first line is the question,the lines 2 to 5 is the options and the 6th line is the answer key and there are more than 100 questions and I should print random questions and its corresponding choices each time I open the application and it should not repeat the same question.Can any one give me a code snippet for this?
Imports System.IO
Imports System.Runtime.InteropServices
Public Class Quiz
Public ques As Integer = 1
Dim Shuffle As Integer = 0
Dim SCORE As Integer = 0
Dim val As Integer = 30
Public anskey As String
Private currentQuestion As Integer
Private listOfQuestions As List(Of Question) = New List(Of Question)
<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)>
Private Shared Function SendMessage(ByVal hWnd As IntPtr, ByVal Msg As UInteger, ByVal wParam As Integer, ByVal lParam As Integer) As IntPtr
End Function
Public Sub Reset_all()
val = 30
SCORE = 0
ProgressBar1.Value = 0
Button3.Hide()
ProgressBar1.Minimum = 0
ProgressBar1.Maximum = 30
Timer1.Enabled = True
Using reader = New System.IO.StreamReader("Quiz.txt")
Dim line = reader.ReadLine()
While (Not String.IsNullOrWhiteSpace(line))
Dim question = New Question
question.Question = line
question.Choice1 = reader.ReadLine()
question.Choice2 = reader.ReadLine()
question.Choice3 = reader.ReadLine()
question.Choice4 = reader.ReadLine()
question.Answer = reader.ReadLine()
listOfQuestions.Add(question)
line = reader.ReadLine()
End While
End Using
If listOfQuestions.Count > 0 Then
LoadQuestion(0)
End If
End Sub
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
Reset_all()
End Sub
Sub LoadQuestion(questionIndex As Integer)
Dim question = listOfQuestions(questionIndex)
currentQuestion = questionIndex
If listOfQuestions.Count - 1 = currentQuestion Then
End If
With question
Label3.Text = ques
Label1.Text = .Question
RadioButton1.Text = .Choice1
RadioButton2.Text = .Choice2
RadioButton3.Text = .Choice3
RadioButton4.Text = .Choice4
anskey = .Answer
End With
End Sub
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
If (SCORE > 0) Then
SCORE -= 1
End If
If (currentQuestion > 0) Then
If (ques > 0) Then
ques -= 1
LoadQuestion(currentQuestion - 1)
End If
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
If (anskey = "a" And RadioButton1.Checked = True Or anskey = "b" And RadioButton2.Checked = True Or anskey = "c" And RadioButton3.Checked = True Or anskey = "d" And RadioButton4.Checked = True) Then
SCORE += 1
End If
If (currentQuestion < listOfQuestions.Count - 1) Then
If (ques <= 99) Then
ques += 1
LoadQuestion(currentQuestion + 1)
End If
End If
End Sub
Private Sub Quiz_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
Dashboard.Show()
Me.Hide()
End Sub
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
ProgressBar1.Value += 1
val -= 1
Label2.Text = val & " Sec"
If ProgressBar1.Value = ProgressBar1.Maximum Then
Timer1.Enabled = False
End If
If ProgressBar1.Value > 23 Then
SendMessage(ProgressBar1.Handle, 1040, 2, 0)
Button3.Show()
End If
If ProgressBar1.Value = 30 Then
End If
End Sub
Private Sub SubmitResult()
MsgBox("You have Scored " + SCORE.ToString + " Out of 100")
End Sub
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim Re As Integer = MsgBox("Are you sure you want to submit?",
vbYesNo, "Submit")
If (Re = 6) Then
SubmitResult()
Try
Me.Close()
Dashboard.Show()
Catch ex As Exception
End Try
End If
End Sub
Private Sub Label1_Click(sender As Object, e As EventArgs) Handles Label1.Click
End Sub
End Class
Public Class Question
Public Property Question As String
Public Property Choice1 As String
Public Property Choice2 As String
Public Property Choice3 As String
Public Property Choice4 As String
Public Property Answer As String
End Class

Answer 1

I would make a class "question" like this:
public Class Question
public questionas String
public answer1 as String
public answer2 as String
public answer3 as String
public answer4 as String
public correctAnswer as integer
public sub new(que as string, a1 as string, a2 as string, a3 as string, a4 as string, answer as integer)
question= que
answer1=a1
answer2=a2
answer3=a3
answer4=a4
correctAnswer=answer
end sub
end Class
Now load all your questions in the programm like this:
Imports System
Imports System.IO
Class MainWindow
private listQuestions as List(Of Question)
Public Sub window_loaded() handles MainWindow.loaded
listQuestions = loadAllQuestions()
End Sub
private function loadAllQuestions() as List(Of Question)
Dim str() As String
Try
' Open the file using a stream reader.
Using sr As New StreamReader("example.txt")
Dim line As String
' Read the stream to a string and write the string to the console.
line = sr.ReadToEnd()
Str = line.Split(vbNewLine)
End Using
Catch e As Exception
Console.WriteLine("The file could not be read:")
Console.WriteLine(e.Message)
End Try
'So now put the questions in your list:
dim list as new List(Of Question)
For i = 0 to str.count - 1
if (i+1) mod 5 = 0 then 'is divible without rest by 6
list.add(new Question(str(i-5), str(i-4), str(i-3), str(i-2), str(i-1), str(i))
end if
next
return list
end sub
'Load a random question:
private sub btNext_click() handles btNext.click()
dim ranQuestion as Question
dim r as new random
ranQuestion = listFragen.item(r.next(0,listQuestions.count))
End Class
Hope i could help you. To prevent that the programm can show the same question again its your job :)

Answer 2

First, I would recommend using the File.ReadAllLines() function to get an array of lines in the text file with questions. Then you can access them easily.
If you observe, the index of the line of the question will be (n - 1) * 6, where n is the question number. Once you get that, the indices of the options are given by:
i + 1
i + 2
i + 3
i + 4
where i = (n - 1) * 6. The answer key is given by:
i + 5
That should get you started. If you get stuck, leave a comment :)
So you would do the first part by:
Dim lines() As String = File.ReadAllLines("<yourQuestions.txt")
Then, you can generate a random number within the required range using:
Dim questionNumber As Integer = Random.Next(1, (lines.Length / 6) + 1)
After that, you can retrieve the question, options and answer key by:
Dim i As Integer = (questionNumber - 1) * 6
Dim question As String = lines(i)
Dim options() As String = {lines(i + 1), lines(i + 2), lines(i + 3), lines(i + 4)}
Dim answerKey As String = lines(Integer.Parse(lines(i + 5)))
You can also consider creating a class Question:
Public Class Question
Public Property Question As String
Public Property Choice1 As String
Public Property Choice2 As String
Public Property Choice3 As String
Public Property Choice4 As String
Public Property Answer As String
Public Sub New(q As String, c1 As String, c2 As String, c3 As String, c4 As String, ans As String)
Question = q
Choice1 = c1
Choice2 = c2
Choice3 = c3
Choice4 = c4
Answer = ans
End Sub
End Class
Then you can assign the properties.
Another alternative (might be better in performance, in fact, I think it should be) would be to use the File.ReadLines() function and use the Take() and Skip() extension methods of IEnumerable<T> (LINQ):
Dim questionNumber As Integer = Random.Next(1, (File.ReadLines("<yourQuestions.txt").Count() / 6) + 1)
Dim blockLines = File.ReadLines("<yourQuestions.txt").Skip((questionNumber - 1) * 6).Take(6)
Dim currentQuestion As New Question(blockLines(0), blockLines(1), blockLines(2), blockLines(3), blockLines(4), blockLines(blockLines(5)))

Answer 3

To start with, load your questions this way:
Dim questions = _
File _
.ReadLines("questions.txt") _
.Select(Function (x, n) New With { .Line = X, .Index = n }) _
.GroupBy(Function (xn) xn.Index \ 6, Function (xn) xn.Line) _
.Select(Function (xs) New Question() With _
{ _
.Question = xs(0), _
.Choice1 = xs(1), _
.Choice2 = xs(2), _
.Choice3 = xs(3), _
.Choice4 = xs(4), _
.Answer = xs(5) _
}) _
.ToArray()
That'll give you an array for your questions:
Next, you need to create a "queue.txt" file that contains the indices of your questions in a random order that you wish to display them in. Here's how to create your queue:
Dim rnd = New Random()
Dim queue = _
Enumerable _
.Range(0, questions.Length) _
.OrderBy(Function (n) rnd.Next()) _
.Select(Function (n) n.ToString()) _
.ToArray()
File.WriteAllLines("queue.txt", queue)
Then when you load your program, you can read this file and choose the next question to ask, and save the file, skipping the first question for next time, like this:
Dim queue = File.ReadAllLines("queue.txt")
Dim questionToAsk As Question = questions(Integer.Parse(queue.First()))
File.WriteAllLines("queue.txt", queue.Skip(1))
It would be up to you to make sure that the file is created when it doesn't exist and to write the code that checks if you've asked all the questions and need to re-create the queue.

Answer 4

Here are the basics of a class that uses XML.
Public Class QuestionAndAnswer
'the container for all questions/answers
Private ReadOnly qa As XElement = <QandA></QandA>
'the container for a question and some number of possible answers
Private ReadOnly ent As XElement = <entry></entry>
'the question
Private ReadOnly aquestion As XElement = <question></question>
'an answer - the c attribute will be "y" for the correct answer
Private ReadOnly ananswer As XElement = <answer c=""></answer>
Private theQA As XElement
Public Sub New()
Me.theQA = New XElement(qa) 'set up
End Sub
Public Sub New(path As String)
Me.theQA = XElement.Load(path)
End Sub
Public Sub Save(path As String)
Me.theQA.Save(path)
End Sub
Private Function AddQuestion(theQuestion As String, correctAnsw As String) As XElement
Dim e As New XElement(ent)
Dim q As New XElement(aquestion)
Dim a As New XElement(ananswer)
q.Value = theQuestion
a.Value = correctAnsw
a.#c = "y"
e.Add(q)
e.Add(a)
Me.theQA.Add(e)
Return e
End Function
Public Function AddQuestion(theQuestion As String, correctAnsw As String,
ans1 As String) As XElement
Dim e As XElement = Me.AddQuestion(theQuestion, correctAnsw)
Dim a As New XElement(ananswer)
a.Value = ans1
e.Add(a)
Return e
End Function
Public Function AddQuestion(theQuestion As String, correctAnsw As String,
ans1 As String, ans2 As String) As XElement
Dim e As XElement = Me.AddQuestion(theQuestion, correctAnsw, ans1)
Dim a As New XElement(ananswer)
a.Value = ans2
e.Add(a)
Return e
End Function
Public Function AddQuestion(theQuestion As String, correctAnsw As String,
ans1 As String, ans2 As String, ans3 As String) As XElement
Dim e As XElement = Me.AddQuestion(theQuestion, correctAnsw, ans1, ans2)
Dim a As New XElement(ananswer)
a.Value = ans3
e.Add(a)
Return e
End Function
Public Function AddQuestion(theQuestion As String, correctAnsw As String,
ans1 As String, ans2 As String, ans3 As String, ans4 As String) As XElement
Dim e As XElement = Me.AddQuestion(theQuestion, correctAnsw, ans1, ans2, ans3)
Dim a As New XElement(ananswer)
a.Value = ans4
e.Add(a)
Return e
End Function
Private Shared prng As New Random
Public LastQuestionAnswer As String
Public Function RandomQuestion() As String
Dim q As XElement = Me.SelectRandomQ
If q IsNot Nothing Then
Dim rv As New System.Text.StringBuilder
rv.AppendLine(q.<question>.Value)
rv.AppendLine()
Dim ie As IEnumerable(Of XElement)
ie = From qa In q.<answer>
Select qa
ie = ie.OrderBy(Function() prng.Next(q.<answer>.Count))
Dim x As Integer = 1
For Each a As XElement In ie
If a.#c = "y" Then
Me.LastQuestionAnswer = x.ToString
End If
rv.AppendFormat("{0}. {1}", x, a.Value)
rv.AppendLine()
x += 1
Next
rv.AppendLine()
Me.LastQuestionAnswer = Me.LastQuestionAnswer.Insert(0, rv.ToString)
Debug.WriteLine(Me.LastQuestionAnswer)
Return rv.ToString
End If
Return ""
End Function
Private Function SelectRandomQ() As XElement
If Me.theQA IsNot Nothing AndAlso Me.theQA.<entry>.Count > 0 Then
Dim ie As IEnumerable(Of XElement)
ie = From ent In Me.theQA.Elements
Where ent.#used <> "y"
Select ent
Dim rv As XElement = ie(prng.Next(ie.Count))
rv.#used = "y"
Return rv
End If
Return Nothing
End Function
End Class
A form with a richtextbox and a button shows it
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim foo As New QuestionAndAnswer
foo.RandomQuestion()
foo.AddQuestion("Which Vietnam War film directed by Francis Ford Coppola followed a screenplay based on famous adventure story Heart of Darkness?",
"Apocalypse Now",
"Good Morning Vietnam",
"Born on the Fourth of July",
"Band of Brothers")
foo.AddQuestion("What was the name of the baseball pitcher that hit a bird with a pitch during a 2001 Spring Training game?",
"Randy Johnson",
"Mike Mussina",
"Roger Clemens",
"Greg Maddux",
"Johan Santana")
foo.AddQuestion("The third largest desert in the world is the Sahara, what is the first?",
"Antarctic",
"Gobi",
"Sonoran")
foo.AddQuestion("How many US presidents have died while in office?",
"8",
"6",
"7")
foo.AddQuestion("If x is the first of five consecutive odd numbers > 0, then what is their average?",
"x + 4",
"x",
"x + 1",
"x + 3")
Dim qa As New System.Text.StringBuilder
foo.RandomQuestion()
qa.AppendLine(foo.LastQuestionAnswer)
qa.AppendLine()
foo.RandomQuestion()
qa.AppendLine(foo.LastQuestionAnswer)
qa.AppendLine()
foo.RandomQuestion()
qa.AppendLine(foo.LastQuestionAnswer)
RichTextBox1.Text = qa.ToString
End Sub