Question

Visual Basic

You are asked to develop a Visual Basic Net application that can determine roots of a requirements of this project are as follows: 1) Design a form to allow users to define a quadratic equation and to find the roots of the equation. The form should have a label that shows this message: Solving a quadratic equation ax2+bx+c=0 The form should have three textboxes in which users enter the values of a, b, and c The form should have two more textboxes in which the roots are displayed. The form should have three buttons: Calculate, Clear, and Exit Quadratic Equation E3 Solving a quadratic equation a"X"2 + b*x +c = 0 lol 04 Clear Exit 2) When the "Calculate" button is clicked, the roots are calculated and displayed. The application should be able to determine both real and imaginary roots. 3) When the "Clear" button is clicked, all the textboxes will be cleared. 4) When the "Exit" button is clicked, the application is closed.

Answer 1

VB.Net Application:

File: Form1.Designer.vb

<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class Form1
    Inherits System.Windows.Forms.Form

    'Form overrides dispose to clean up the component list.
    <System.Diagnostics.DebuggerNonUserCode()> _
    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        Try
            If disposing AndAlso components IsNot Nothing Then
                components.Dispose()
            End If
        Finally
            MyBase.Dispose(disposing)
        End Try
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.
    'Do not modify it using the code editor.
    <System.Diagnostics.DebuggerStepThrough()> _
    Private Sub InitializeComponent()
        Me.Label1 = New System.Windows.Forms.Label()
        Me.Label2 = New System.Windows.Forms.Label()
        Me.Label3 = New System.Windows.Forms.Label()
        Me.txt_a = New System.Windows.Forms.TextBox()
        Me.txt_b = New System.Windows.Forms.TextBox()
        Me.Label4 = New System.Windows.Forms.Label()
        Me.txt_c = New System.Windows.Forms.TextBox()
        Me.Label5 = New System.Windows.Forms.Label()
        Me.txt_x1 = New System.Windows.Forms.TextBox()
        Me.Label6 = New System.Windows.Forms.Label()
        Me.txt_x2 = New System.Windows.Forms.TextBox()
        Me.Label7 = New System.Windows.Forms.Label()
        Me.btnCalculate = New System.Windows.Forms.Button()
        Me.btnClear = New System.Windows.Forms.Button()
        Me.btnExit = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        '
        'Label1
        '
        Me.Label1.AutoSize = True
        Me.Label1.Font = New System.Drawing.Font("Microsoft Sans Serif", 12.0!, CType((System.Drawing.FontStyle.Bold Or System.Drawing.FontStyle.Italic), System.Drawing.FontStyle), System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label1.Location = New System.Drawing.Point(140, 25)
        Me.Label1.Name = "Label1"
        Me.Label1.Size = New System.Drawing.Size(237, 20)
        Me.Label1.TabIndex = 0
        Me.Label1.Text = "Solving a quadratic equation"
        '
        'Label2
        '
        Me.Label2.AutoSize = True
        Me.Label2.Font = New System.Drawing.Font("Microsoft Sans Serif", 12.0!, CType((System.Drawing.FontStyle.Bold Or System.Drawing.FontStyle.Italic), System.Drawing.FontStyle), System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label2.Location = New System.Drawing.Point(168, 45)
        Me.Label2.Name = "Label2"
        Me.Label2.Size = New System.Drawing.Size(156, 20)
        Me.Label2.TabIndex = 1
        Me.Label2.Text = "a*x^2 + b*x + c = 0"
        '
        'Label3
        '
        Me.Label3.AutoSize = True
        Me.Label3.Font = New System.Drawing.Font("Microsoft Sans Serif", 11.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label3.Location = New System.Drawing.Point(62, 106)
        Me.Label3.Name = "Label3"
        Me.Label3.Size = New System.Drawing.Size(22, 18)
        Me.Label3.TabIndex = 2
        Me.Label3.Text = "a:"
        '
        'txt_a
        '
        Me.txt_a.Location = New System.Drawing.Point(100, 104)
        Me.txt_a.Name = "txt_a"
        Me.txt_a.Size = New System.Drawing.Size(55, 20)
        Me.txt_a.TabIndex = 3
        '
        'txt_b
        '
        Me.txt_b.Location = New System.Drawing.Point(233, 104)
        Me.txt_b.Name = "txt_b"
        Me.txt_b.Size = New System.Drawing.Size(55, 20)
        Me.txt_b.TabIndex = 5
        '
        'Label4
        '
        Me.Label4.AutoSize = True
        Me.Label4.Font = New System.Drawing.Font("Microsoft Sans Serif", 11.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label4.Location = New System.Drawing.Point(195, 106)
        Me.Label4.Name = "Label4"
        Me.Label4.Size = New System.Drawing.Size(22, 18)
        Me.Label4.TabIndex = 4
        Me.Label4.Text = "b:"
        '
        'txt_c
        '
        Me.txt_c.Location = New System.Drawing.Point(365, 104)
        Me.txt_c.Name = "txt_c"
        Me.txt_c.Size = New System.Drawing.Size(55, 20)
        Me.txt_c.TabIndex = 7
        '
        'Label5
        '
        Me.Label5.AutoSize = True
        Me.Label5.Font = New System.Drawing.Font("Microsoft Sans Serif", 11.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label5.Location = New System.Drawing.Point(327, 106)
        Me.Label5.Name = "Label5"
        Me.Label5.Size = New System.Drawing.Size(22, 18)
        Me.Label5.TabIndex = 6
        Me.Label5.Text = "c:"
        '
        'txt_x1
        '
        Me.txt_x1.Location = New System.Drawing.Point(106, 173)
        Me.txt_x1.Name = "txt_x1"
        Me.txt_x1.Size = New System.Drawing.Size(117, 20)
        Me.txt_x1.TabIndex = 9
        '
        'Label6
        '
        Me.Label6.AutoSize = True
        Me.Label6.Font = New System.Drawing.Font("Microsoft Sans Serif", 11.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label6.Location = New System.Drawing.Point(62, 175)
        Me.Label6.Name = "Label6"
        Me.Label6.Size = New System.Drawing.Size(45, 18)
        Me.Label6.TabIndex = 8
        Me.Label6.Text = "x1 = "
        '
        'txt_x2
        '
        Me.txt_x2.Location = New System.Drawing.Point(330, 173)
        Me.txt_x2.Name = "txt_x2"
        Me.txt_x2.Size = New System.Drawing.Size(117, 20)
        Me.txt_x2.TabIndex = 11
        '
        'Label7
        '
        Me.Label7.AutoSize = True
        Me.Label7.Font = New System.Drawing.Font("Microsoft Sans Serif", 11.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.Label7.Location = New System.Drawing.Point(286, 175)
        Me.Label7.Name = "Label7"
        Me.Label7.Size = New System.Drawing.Size(45, 18)
        Me.Label7.TabIndex = 10
        Me.Label7.Text = "x2 = "
        '
        'btnCalculate
        '
        Me.btnCalculate.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.btnCalculate.Location = New System.Drawing.Point(32, 272)
        Me.btnCalculate.Name = "btnCalculate"
        Me.btnCalculate.Size = New System.Drawing.Size(123, 35)
        Me.btnCalculate.TabIndex = 12
        Me.btnCalculate.Text = "Calculate"
        Me.btnCalculate.UseVisualStyleBackColor = True
        '
        'btnClear
        '
        Me.btnClear.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.btnClear.Location = New System.Drawing.Point(179, 272)
        Me.btnClear.Name = "btnClear"
        Me.btnClear.Size = New System.Drawing.Size(123, 35)
        Me.btnClear.TabIndex = 13
        Me.btnClear.Text = "Clear"
        Me.btnClear.UseVisualStyleBackColor = True
        '
        'btnExit
        '
        Me.btnExit.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
        Me.btnExit.Location = New System.Drawing.Point(324, 272)
        Me.btnExit.Name = "btnExit"
        Me.btnExit.Size = New System.Drawing.Size(123, 35)
        Me.btnExit.TabIndex = 14
        Me.btnExit.Text = "Exit"
        Me.btnExit.UseVisualStyleBackColor = True
        '
        'Form1
        '
        Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
        Me.ClientSize = New System.Drawing.Size(508, 369)
        Me.Controls.Add(Me.btnExit)
        Me.Controls.Add(Me.btnClear)
        Me.Controls.Add(Me.btnCalculate)
        Me.Controls.Add(Me.txt_x2)
        Me.Controls.Add(Me.Label7)
        Me.Controls.Add(Me.txt_x1)
        Me.Controls.Add(Me.Label6)
        Me.Controls.Add(Me.txt_c)
        Me.Controls.Add(Me.Label5)
        Me.Controls.Add(Me.txt_b)
        Me.Controls.Add(Me.Label4)
        Me.Controls.Add(Me.txt_a)
        Me.Controls.Add(Me.Label3)
        Me.Controls.Add(Me.Label2)
        Me.Controls.Add(Me.Label1)
        Me.Name = "Form1"
        Me.Text = "Quadratic Equation"
        Me.ResumeLayout(False)
        Me.PerformLayout()

    End Sub
    Friend WithEvents Label1 As System.Windows.Forms.Label
    Friend WithEvents Label2 As System.Windows.Forms.Label
    Friend WithEvents Label3 As System.Windows.Forms.Label
    Friend WithEvents txt_a As System.Windows.Forms.TextBox
    Friend WithEvents txt_b As System.Windows.Forms.TextBox
    Friend WithEvents Label4 As System.Windows.Forms.Label
    Friend WithEvents txt_c As System.Windows.Forms.TextBox
    Friend WithEvents Label5 As System.Windows.Forms.Label
    Friend WithEvents txt_x1 As System.Windows.Forms.TextBox
    Friend WithEvents Label6 As System.Windows.Forms.Label
    Friend WithEvents txt_x2 As System.Windows.Forms.TextBox
    Friend WithEvents Label7 As System.Windows.Forms.Label
    Friend WithEvents btnCalculate As System.Windows.Forms.Button
    Friend WithEvents btnClear As System.Windows.Forms.Button
    Friend WithEvents btnExit As System.Windows.Forms.Button

End Class

File: Form1.vb

Public Class Form1

    ' Clear button click event handler
    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click

        ' Clearing values
        txt_a.Clear()
        txt_b.Clear()
        txt_c.Clear()
        txt_x1.Clear()
        txt_x2.Clear()

    End Sub

    ' Exit button click event handler
    Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click

        Application.Exit()

    End Sub

    'Calculate button click event handler
    Private Sub btnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculate.Click

        Dim a, b, c, x1, x2 As Double

        'Fetching values from textbox
        a = txt_a.Text
        b = txt_b.Text
        c = txt_c.Text

        Dim det As Double

        'Calculating determinant
        det = (b * b - 4 * a * c)

        ' If determinant is greater than 0
        If (det > 0) Then

            ' Calculating real part
            x1 = (-b + Math.Sqrt(det)) / (2 * a)
            x2 = (-b - Math.Sqrt(det)) / (2 * a)

            ' Writing results to text boxes
            txt_x1.Text = x1.ToString("0.00")
            txt_x2.Text = x2.ToString("0.00")
   
        ElseIf det = 0 Then

            ' Calculating real part
            x1 = x2 = (-b + Math.Sqrt(det)) / (2 * a)

            ' Writing results to text boxes
            txt_x1.Text = x1.ToString("0.00")
            txt_x2.Text = x2.ToString("0.00")

        Else

            Dim img1, img2 As Double

            'Calculating real part
            x1 = -b / (2.0 * a)
            x2 = -b / (2.0 * a)

            'Calculating imaginary part
            img1 = (Math.Sqrt(-det) / (2.0 * a))
            img2 = (Math.Sqrt(-det) / (2.0 * a))

            ' Writing results to text boxes
            txt_x1.Text = "(" + x1.ToString("0.00") + ") + i (" + img1.ToString("0.00") + ")"
            txt_x2.Text = "(" + x2.ToString("0.00") + ") - i (" + img2.ToString("0.00") + ")"

        End If

    End Sub

End Class

_______________________________________________________________________________________________

Sample Run:

Quadratic Equation Solving a quadratic equation a 7 b: 9 C: 8 x1 = (0.64) + i (-0.85) x2 (0.64)-i (0.85) Calculate Clear Exit