Counter & Accumulators

In programming we often need to Count. To count we must

• Declare an integer variable to hold the “how many” value.
• Add 1 to the variable whenever what ever we want to count happens.
  

To count how many times we click a button
 

    Dim intCount As Integer

    Private Sub btnCount_Click(ByVal sender As System.Object, _
                               ByVal e As System.EventArgs) Handles btnCount.Click
        intCount = intCount + 1

    End Sub

    Private Sub btnReportCount_Click(ByVal sender As System.Object, _
                                     ByVal e As System.EventArgs) Handles btnReportCount.Click
        MsgBox("Button clicked " & intCount & " times")

    End Sub

The pattern for the statement used to count is

A = A + 1         (where A is an integer variable)

We also often have to Accumulate. That is - we have to add up a series of values. To accumulate we must

• Declare a variable to hold the Accumulated Value
• Repeatedly execute a statement that adds each desired value to the accumulator variable
  

To add up values entered in a TextBox

Dim decSumPrice As Decimal

Private Sub btnAddEmUp_Click(ByVal sender As System.Object, _
                             ByVal e As System.EventArgs) Handles btnAddEmUp.Click

        Dim decPrice As Decimal

        If IsNumeric(txtPrice.Text) Then

            decPrice = Convert.ToDecimal(txtPrice.Text)
            decSumPrice = decSumPrice + decPrice

        End If
End Sub

Private Sub btnReportSum_Click(ByVal sender As System.Object, _
                               ByVal e As System.EventArgs) Handles btnReportSum.Click

        MsgBox("Sum of numbers entered " & decSumPrice)
End Sub

 
The pattern for the statement used to add up a series of values is

A = A + B         (where A is the accumulator variable and B
                           contains the value you want to add up.)