Keeping a Running Total

Many applications such as a checkbook may need to keep a running balance of 
all transactions.  This example shows how to keep such a running balance by 
using the @XLOOKUP and @NUMBER functions.

In this example we will use the following fields:

              Check #:                 numeric field
              Check amount:            money field
              Deposit amount:          money field
              Current Num:             numeric field
              Previous Bal:            money field
              Current Bal:             money field

Other fields may be added, but these are all that will be used for the 
calculations.

Select Speed up searches from the Customize Menu and put an S in the Current
Num field.

Enter the following on the Program Spec:

    Check #: #1

    Check amount: #2

    Deposit amount: #3

    Current Num: <#4: IF #4 = "" THEN #4=@NUMBER; GOTO #5

    PreviousBal: <#5: #5 = @XLOOKUP(@FILENAME, #4-1, "Current Num", "Current
                   Bal"); GOTO #6

    Current Bal: <#6 = #5 - #2 + #3

When adding new records, the balance from the last entered record will be
placed in the Previous Bal field of the new record.  The Current Bal will be 
calculated depending on the check or deposit amounts.


Caution: Do not escape from a form if the Current Num field has been filled
         in.  Instead enter a form with a Check amount of zero (0) and no
         check #.  If the Current num field skips a number there will be no
         value for the Xlookup statement to match and the Previous Bal will
         become zero.






Application:  A checking account could use this to keep a running balance.



Q & A Application Note       Rev. 6/92           #2201     Page 1 of 1