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Unit 6: VB Control Structure

Dim sc as New ScreenMode
Dim b as Boolean
b = sc.FindFirstMode
While b
MsgBox “BitDepth = “ & sc.BitDepth & “\nColor = “ & sc.Color
b = sc.FindNextMode
Wend
End Sub

6.5 For... Next Loops

When we know exactly how many times a loop should be executed, a special type of loop, called
a For... Next loop, can be used. For... Next loops are easy to read and write, and have features
that make them ideal for certain common tasks. The following code uses a For... Next loop to
display a table:

Private Sub btnDisplayTable_Click(...) Handles btnDisplayTable.Click
‘Display a table of the first 5 numbers and their squares
‘Assume the font for lstTable is Courier New
Dim i As Integer
For i = 1 To 5
lstTable.Items.Add(i & “ “ & i ^ 2)
Next
End Sub
[Run, and click on btnDisplayTable. The following is displayed in the list
box.]
1 1
2 4
3 9
4 16
5 25
The equivalent program written with a Do loop is as follows.
Private Sub btnDisplayTable_Click(...) Handles btnDisplayTable.Click
‘Display a table of the first 5 numbers and their squares

Dim i As Integer
i = 1
Do While i <= 5

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