Option Strict On
Option Explicit On
Public Class frmMain
    'Variables global to the form
    Dim randNum1, randNum2 As Integer

    'When the form loads...
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Acts like it is clicking the generate new range button
        btnNewRange.PerformClick()
    End Sub

    'When the new range button is clicked...
    Private Sub btnNewRange_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNewRange.Click
        'Generates new range and then displays the question in the question label, this time it does integers
        randNum1 = CInt(10.0 * Rnd())
        randNum2 = randNum1 + CInt(10.0 * Rnd())

        lblQuestion.Text = "Please enter a number between " & CStr(randNum1) & " and " & CStr(randNum2)
    End Sub

    'When the submit button is clicked...
    Private Sub btnSubmit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubmit.Click
        Dim answer As Double
        'First checks if the answer in the text box is a number
        If IsNumeric(txtAnswer.Text) Then
            answer = CDbl(txtAnswer.Text)
            'Then it checks if the answer is in the correct range, then displays appropriate message, also
            'checks if the answer is exactly one of the numbers on the range
            If answer > randNum1 And answer < randNum2 Then
                MessageBox.Show("You are correct!", "You are correct!")
            ElseIf answer = randNum1 Then
                MessageBox.Show("Your answer is exactly the lower bound", "Kind of correct.")
            ElseIf answer = randNum2 Then
                MessageBox.Show("Your answer is exactly the upper bound", "Kind of correct.")
            Else
                MessageBox.Show("You are incorrect...", "You are incorrect...")
            End If
        Else
            MessageBox.Show("Please Enter a Valid Number", "Please Enter a Valid Number")
        End If
    End Sub
End Class