Program using visual basic.net You will create a very simple two numbers calcula

Question

Program using visual basic.net

You will create a very simple two numbers calculator with save options; here is the specifications for the application. Create a form divided vertically in two halves with right and left panels.

1- In the left panel, you will create the following controls, the labels or the value of the control will be in "" and the type of the control will in []

a- "First Number" [textbox1]

b- "Second number" [textbox2]

c- "Result" [textbox3] - read only

d- "+" [push button] "-" [push button] "/" [push button] "*" [push button] "Save" [push button] "Display" [push button]

2- Operations. The user will enter two numbers in the "First Number" and the "Second Number", then press the "+" for addition, "-" for subtraction, "*" multiplication and "/" the result will be displayed in the result [textbox3], if the user clicked "[save]" then the operation can be displayed in the right panel when the user press [Display]

Please note: that the user can save up to 10 operations. Add "clear" [push button] on the right panel to clear the content, make sure that you trap all the errors and set the focus to the appropriate control after the error occurred

. Make sure that the result contains the operations, I should see in the right panel something like this.

1+1=2

1*2=2 and so on.

Instructions: You must trap divided by Zero and a display a message to the user “Cannot Divide by Zero”, allow the user to renter another value.

The main issue is figuring out how to limit the saved items added to the file to 10

You have some aswer in your website but are not working.

Explanation / Answer

Public Class Form1
    Dim decNum1 As Decimal
    Dim decNum2 As Decimal
    Dim decNum3 As Decimal
    Dim count As Integer = 0

    Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click
        Decimal.TryParse(txtNum1.Text, decNum1)
        Decimal.TryParse(txtNum2.Text, decNum2)

        ' add num 1 and 2 and display results
        decNum3 = decNum1 + decNum2
        txtNum3.Text = decNum1 & " + " & decNum2 & " = " & decNum3

    End Sub

    Private Sub btnSubtract_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSubtract.Click
        ' accept input from text box 1 and 2
        Decimal.TryParse(txtNum1.Text, decNum1)
        Decimal.TryParse(txtNum2.Text, decNum2)

        ' subtract num 2 from num 1 and display results
        decNum3 = decNum1 - decNum2
        txtNum3.Text = decNum1 & " - " & decNum2 & " = " & decNum3

    End Sub

    Private Sub btnMultiply_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnMultiply.Click
        ' accept input from text box 1 and 2
        Decimal.TryParse(txtNum1.Text, decNum1)
        Decimal.TryParse(txtNum2.Text, decNum2)

        ' multiply num 1 and 2 and display results
        decNum3 = decNum1 * decNum2
        txtNum3.Text = decNum1 & " X " & decNum2 & " = " & decNum3

    End Sub

    Private Sub btnDivide_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDivide.Click
        ' accept input from text box 1 and 2
        Decimal.TryParse(txtNum1.Text, decNum1)
        Decimal.TryParse(txtNum2.Text, decNum2)

        ' divide num 1 by num 2 and display results
        Try
            decNum3 = decNum1 / decNum2
        Catch ex As DivideByZeroException When decNum2 = 0
            MessageBox.Show("Cannot divide by 0. Please enter a valid number.")
            txtNum2.Focus()
        End Try
        txtNum3.Text = decNum1 & " / " & decNum2 & " = " & decNum3

    End Sub

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
        ' clears list box
        lstOperations.Items.Clear()
    End Sub

    Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
        If (count < 10) Then
            ' writes up to 10 operations to sequential access files
            Dim outFile As IO.StreamWriter
            outFile = IO.File.AppendText("operations.txt")
            outFile.WriteLine(txtNum3.Text)
            outFile.Close()
            count = count + 1
        End If

    End Sub

    Private Sub btnDisplay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplay.Click
        ' reads operations from a sequential access file and displays them in list box

        ' declare variables
        Dim inFile As IO.StreamReader
        Dim strOperation As String

        ' clears previous operations from list box
        lstOperations.Items.Clear()

        ' determine wether file exists
        If IO.File.Exists("operations.txt") Then
            ' open the file for input
            inFile = IO.File.OpenText("operations.txt")
            ' process loop instructions until end of file
            Do Until inFile.Peek = -1
                ' read operation
                strOperation = inFile.ReadLine
                ' add operation to list box
                lstOperations.Items.Add(strOperation)
            Loop

            ' close the file
            inFile.Close()
        Else
            MessageBox.Show("No savefile exists to display.")
        End If
    End Sub
    Private Sub input_validation(ByVal sender As Object, ByVal e As KeyPressEventArgs) Handles txtNum1.KeyPress, txtNum2.KeyPress
        ' validate input is a number 0-9
        If (e.KeyChar < "0" OrElse e.KeyChar > "9") AndAlso e.KeyChar <> "." AndAlso e.KeyChar <> ControlChars.Back Then
            e.Handled = True
        End If
    End Sub

End Class

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