Machine Problem

Write a program that will ask the user to gived three numbers, and compute the sum of that numbers.

Use the following formula below.

total_sum = (variable_one + variable_two +variable_three)

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Program Listing

' Addition of Three Numbers Using VB.NET
' Prof. Jake Rodriguez Pomperada, MAED-IT, MIT
' www.jakerpomperada.com  and www.jakerpomperada.blogspot.com
' jakerpomperada@gmail.com
' Bacolod City, Negros Occidental Philippines
' May 16, 2021   Sunday  11:23 AM

Public Class Form1
    ' Button Compute
    Private Sub btnCompute_Click(sender As Object, e As EventArgs) Handles btnCompute.Click
        Dim sum As Integer
        Dim a, b, c As String

        sum = 0

        a = txtValue1.Text
        b = txtValue2.Text
        c = txtValue3.Text

        If a = "" Or IsNumeric(a) = False Then
            MessageBox.Show("Please enter a numeric value.")
            txtValue1.Focus()
        ElseIf b = "" Or IsNumeric(b) = False Then
            MessageBox.Show("Please enter a numeric value.")
            txtValue2.Focus()
        ElseIf c = "" Or IsNumeric(c) = False Then
            MessageBox.Show("Please enter a numeric value.")
            txtValue3.Focus()
        Else
            sum = Val(a) + Val(b) + Val(c)
            MessageBox.Show("The sum of " & a & "," & b & ", and " & c & " is " & sum & ".", "The Result")
        End If
    End Sub

    'Button Quit
    Private Sub btnQuit_Click(sender As Object, e As EventArgs) Handles btnQuit.Click
        Dim result = MessageBox.Show(" Are you sure you want to quit the program?", "Confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
        If result = DialogResult.Yes Then
            Me.Close()
        Else
            Me.Show()
            txtValue1.Text = ""
            txtValue2.Text = ""
            txtValue3.Text = ""
            txtValue1.Focus()
        End If
    End Sub
    
    'Button Clear
    Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click
        txtValue1.Text = ""
        txtValue2.Text = ""
        txtValue3.Text = ""
        txtValue1.Focus()
    End Sub
End Class