ANSWERS FOR CSC 336 MIDTERM EXAM -- WINTER 2004

Part A.

1. (d)  Both (b) and (c) are true.

2. (e)  All of the above.  Obvious.

3. (c) A user interface should be consistant in font, color, and control
       arrangement.  It should also be intuitive and user friendly.
       Complexity is NOT a good attribute of a user interface.

4. (d) Option Strict On means that no automatic type conversions are
       allowed.  The CType function must be used to explicitly change 
       one datatype to another.

6. (a) (b - a = 2 And a * c < 20) & " " & (False Or b <> 5)
       (5 - 3 = 2 And 3 * 7 < 20) & " " & (False Or 5 <> 5)
         (True    And   False)    & " " & (False Or  False)
                 False            & " " &      False

7. (c) New is used to invoke a constructor.  We are only talking about
       invocation, not definition.

8. (d) A line in a csv file can contain 1 or 2 fields as well as 3 or more.

9. (a) Dim a(9) As Integer defines an array with indices 0, ... , 9, which
       means 10 elements.  (c) and (d) each define an array with one element.

10. (d) A Pen object is not needed to draw text in a list box.


Part B.

1.  Public Sub picInput_MouseUp(sender As Object, e As Args) _
        Handles picInput.MouseUp

        Dim p As String
        p = e.X & " " & e.Y
        lstPoints.Items.Add(p)
        txtPoints.Text = p
        MessageBox.Show(p)
        Dim r As New StreamReader("c:\Points.txt")
        r.WriteLine(p)
        r.Close()
    End Sub

2.  Public r As StreamReader
    Public Sub Form1_Load(sender As Object, e As Args) _
        Handles MyBase.Load

        r = New StreamReader("c:\Students.txt")
    End Sub

    Public Sub btnSubmit_Click(sender As Object, e As Args) _
        Handles btnSubmit.Click

        Dim sum = 0, count As Integer = 0
        Dim fields() As String
        Dim ave As Double

        line = r.ReadLine()
        While Not IsNothing(line)
            fields = Split(line, ",")
            If fields(1) = "F" And radFemale.Checked Or _
                fields(1) = "M" And radMale.Checked Then
                sum += fields(2)
                count += 1
            End If
            line = r.ReadLine()
        End While
        ave = sum / count
        txtAve.Text = ave.ToString("#0.00")
    End Sub

3.  (a) Public Function SumOfFactors(n As Integer) As Integer
            Dim m As Integer
            Dim sum As Integer = 0

            For m = 0 To n / 2
                If n Mod m = 0 Then
                    sum += m
                End If
            Next
            Return sum
        End Function

    (b) Public Module Main()
            WriteLine(SumOfFactors(12))
            WriteLine(SumOfFactors(9))
            WriteLine(SumOfFactors(7))
        End Module

    (c) Public Sub btnSubmit_Click(sender As Object, e As Args) _
            Handles btnSubmit.Click

            txtSum.Text = SumOfFactors(txtNumber.Text)
        End Sub