: Create a basic calculator that performs addition, subtraction, multiplication, and division using two numbers entered by the user.
Program 5: Simple Registration Form (MS Access / SQL Server)
Examiners look for understanding, not just code that works.
Public Class ListBoxForm Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click If Not String.IsNullOrWhiteSpace(txtItem.Text) Then lstItems.Items.Add(txtItem.Text.Trim()) txtItem.Clear() txtItem.Focus() End If End Sub Private Sub btnRemove_Click(sender As Object, e As EventArgs) Handles btnRemove.Click If lstItems.SelectedIndex <> -1 Then lstItems.Items.RemoveAt(lstItems.SelectedIndex) Else MessageBox.Show("Please select an item to remove.", "Selection Required") End If End Sub Private Sub btnClear_Click(sender As Object, e As EventArgs) Handles btnClear.Click lstItems.Items.Clear() End Sub End Class Use code with caution. Common Error & Fix vb net lab programs for bca students fix
: Determines if a number is prime using loops and conditional logic. Windows Forms and Controls
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These programs generally progress from basic interface handling to backend database connectivity. : Create a basic calculator that performs addition,
Display prime numbers, calculate factorials, or generate Fibonacci series using For , While , or Do-While loops. D. DataGridView and Database Connectivity (ADO.NET)
Public Class CalculatorForm Dim num1, num2, result As Double Private Sub GetInputs() If Double.TryParse(txtNum1.Text, num1) AndAlso Double.TryParse(txtNum2.Text, num2) Then ' Inputs are valid and loaded into num1 and num2 Else MessageBox.Show("Please enter valid numeric values.", "Input Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End If End Sub Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click GetInputs() result = num1 + num2 lblResult.Text = "Result: " & result.ToString() End Sub Private Sub btnSub_Click(sender As Object, e As EventArgs) Handles btnSub.Click GetInputs() result = num1 - num2 lblResult.Text = "Result: " & result.ToString() End Sub Private Sub btnMul_Click(sender As Object, e As EventArgs) Handles btnMul.Click GetInputs() result = num1 * num2 lblResult.Text = "Result: " & result.ToString() End Sub Private Sub btnDiv_Click(sender As Object, e As EventArgs) Handles btnDiv.Click GetInputs() If num2 = 0 Then lblResult.Text = "Cannot divide by zero!" Else result = num1 / num2 lblResult.Text = "Result: " & result.ToString() End If End Sub End Class Use code with caution. Common Lab Bugs & Fixes
To accept 'N' numbers into an array and sort them. Common Error & Fix : Determines if a
Problem 1: "Conversion from String to Type 'Double' is not valid." When reading input from a TextBox . Fix: Use Val() function or Double.TryParse() .
Use meaningful names like btnCalculate instead of Button1 .
Matrix multiplication tests a student's grasp of multi-dimensional arrays and nested For loops. This console application manages a standard 2x2 matrix operation. Complete Code
Dim index As Integer = Array.IndexOf(arr, searchValue) If index <> -1 Then MessageBox.Show("Found at position " & (index+1)) Else MessageBox.Show("Not found") End If
This application calculates total marks, percentage, and assigns grades based on university criteria using conditional structures ( If...Then...Else and Select Case ). Complete Code