Variable scope

Study our note on the scope of variables, and be sure you understand all three sample programs. If you are at all unclear, write the programs and experiment with them.

When you are sure you understand what is going on, turn in answers to the following questions. If I were you, I would answer them by studying the code, then check my answers by writing and testing the programs.

1. A user runs the following program:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim A As String
A = "hohoho"
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim A As String
label1.text = A
End Sub

Explain your answer using the terms "local" and "global" variable.

2. A user runs the following program:

Dim A As String
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim A As String
A = "hohoho"
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
label1.text = A
End Sub

What will be displayed in label1 when the user clicks on Button1 followed by Button2?

Explain your answer using the terms "local" and "global" variable.

3. A user runs the following program:

Dim A As String
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
A = "hohoho"
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
label1.text = A
End Sub

Explain your answer using the terms "local" and "global" variable.