Excel's Formula - sisman

Chapter 24: VBA Programming Concepts 653
When you use For-Next loops, you should understand that the loop counter is a normal
variable — it is not a special type of variable. As a result, you can change the value
of the loop counter within the block of code executed between the For and Next
statements. this is, however, a very bad practice and can cause problems. In fact, you
should take special precautions to ensure that your code does not change the loop
counter.
You also can use a Step value to skip some values in the loop. Here’s the same function rewritten
to sum every other integer between the first and last arguments:
Function SumIntegers2(first, last)
total = 0
For num = first To last Step 2
total = total + num
Next num
SumIntegers2 = Total
End Function
The following formula returns 25, which is the sum of 1, 3, 5, 7, and 9:
=SumIntegers2(1,10)
For-Next loops can also include one or more Exit For statements within the loop. When
this statement is encountered, the loop terminates immediately, as the following example
demonstrates:
Function RowOfLargest(c)
NumRows = Rows.Count
MaxVal = WorksheetFunction.Max(Columns(c))
For r = 1 To NumRows
If Cells(r, c) = MaxVal Then
RowOfLargest = r
Exit For
End If
Next r
End Function
The RowOfLargest function accepts a column number (1–16,384) for its argument and returns the
row number of the largest value in that column. It starts by getting a count of the number of rows
in the worksheet. (This varies, depending on the version of Excel.) This number is assigned to the
NumRows variable. The maximum value in the column is calculated by using the Excel MAX function,
and this value is assigned to the MaxVal variable.