Example Application: Elementary Addition<

	Example Application: Elementary Addition

Elementary Addition

Introduction

This exercise applies the characteristics of a label to assist you with performing elementary additions.

In this application, two numbers are selected randomly. Each number is less than 100. After the form displays these two numbers, the user (the student) is asked to add them and enter the result. The user/student can then click Check to check the result.

Windows Controls:

Practical Learning: Introducing Text Boxes

Create a Window Forms Application named ElementaryAddition2

Design the form as follows:

Control	Text	Name	TextAlign	Font	Additional Properties
Label	00	lblOperand1	Center	Name: Tahoma Size: 48 Bold: True	AutoSize: True ForeColor: Blue
Label	+		Center	Name: Arial Size: 50 Bold: True	AutoSize: True ForeColor: Maroon
Label	00	lblOperand2	Center	Name: Tahoma Size: 48 Bold: True	AutoSize: True ForeColor: Blue
Label	=		Center	Name: Arial Size: 50 Bold: True	AutoSize: True ForeColor: Green
TextBox	000	txtResult	Center	Name: Tahoma Size: 48 Bold: True
Label	New Operation	lblNewOperation	Center	Name: Tahoma, Size: 28 Bold: True	AutoSize: True BorderStyle: Fixed3D ForeColor: White BackColor:Maroon
Label	Check	lblCheckAnswer	Center	Name: Tahoma, Size: 28 Bold: True	AutoSize: True BorderStyle: Fixed3D ForeColor: White BackColor:Maroon
Label	Quit	lblQuit	Center	Name: Tahoma, Size: 28 Bold: True	AutoSize: True BorderStyle: FixedSingle

Double-click the New Operation label and implement its event as follows:

Private Sub lblNewOperationClick(ByVal sender As System.Object, 
                                      ByVal e As System.EventArgs) 
                                      Handles lblNewOperation.Click
        Dim Operand1 As Integer
        Dim Operand2 As Integer

        Dim rndNumber As Random = New Random()

        Operand1 = rndNumber.Next(99)
        Operand2 = rndNumber.Next(99)
        Dim Result As Integer = operand1 + operand2

        lblOperand1.Text = CStr(Operand1)
        lblOperand2.Text = CStr(Operand2)
        txtResult.Text = ""
        txtResult.Focus()
End Sub

In the Class Name combo box, select lblCheckAnswer

In the Method Name combo box, select Click and implement its event as follows:

Private Sub lblCheckAnswerClick(ByVal sender As Object, 
                                     ByVal e As System.EventArgs) 
                                     Handles lblCheckAnswer.Click
        Dim Operand1 As Integer
        Dim Operand2 As Integer
        Dim Result As Integer

        Try

            Operand1 = CInt(lblOperand1.Text)
        Catch
            MsgBox("Invalid Value")
        End Try

        Try
            Operand2 = CInt(lblOperand2.Text)
        Catch
            MsgBox("Invalid Value")
        End Try

        Try
            Result = CInt(txtResult.Text)

            If Result = (Operand1 + Operand2) Then
                MsgBox("WOW - Good Answer")
            Else
                MsgBox("PSSST - Wrong Answer")
            End If
        Catch
            MsgBox("Invalid Answer")
        End Try

        lblNewOperationClick(sender, e)
End Sub

In the Class Name combo box, select lblQuit
In the Method Name combo box, select Click and implement its event as follows:
private void lblQuitClick(object sender, EventArgs e) end End Sub
Execute the application and test it
Click the Close button to close the form and return to your programming environment

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