The Iteration Lab

Or

Multiplying 3 Integers….the Hard Way

This lab is designed to be a simple demonstration of nested iteration using the Do While Loop construct in visual basic. The “product” of three integers entered by the user is calculated by iterated summing of the number 1 (aka counting). The numbers entered by the user to be multiplied are used as termination conditions in the nested loops.

Items to note:

· The numbers entered by the user to be multiplied are used as termination conditions in the nested loops.

· The repeated summing works only with integers.

· The first statement in the loop body increments the iterate variable

· The iterate variables are explicitly initialized

Things to try:

· Very large numbers

· Letters

· No entries

· Floating point numbers

Changes you can make:

· Implement validity checking

· Modify the program to take 4 numbers

Iteration Lab

Private Sub cmdStartIteration_Click()

Dim intNumA As Integer

Dim intNumB As Integer

Dim intNumC As Integer

Dim intCountA As Integer

Dim intCountB As Integer

Dim intCountC As Integer

Dim intRunningSum As Integer

intRunningSum = 0

intNumA = txtNumA

intNumB = txtNumB

intNumC = txtNumC

intCountA = 0

Do While intCountA < intNumA

intCountA = intCountA + 1

intCountB = 0

Do While intCountB < intNumB

intCountB = intCountB + 1

intCountC = 0

Do While intCountC < intNumC

intCountC = intCountC + 1

intRunningSum = intRunningSum + 1

Loop

Loop

Loop

lblAnswer.Caption = Val(intRunningSum)

Me.BackColor = vbBlue

End Sub

Private Sub Form_Load()

txtNumA.Text = ""

txtNumB.Text = ""

txtNumC.Text = ""

lblAnswer.Caption = ""

End Sub