Age Expression Help

[forskare]

I have the following function to determine the age:

function Age as N(DOB as D)
' type your code here

Age = year(date())-year(DOB)
if val(right(cdate(DOB),4)) > val(right(cdate(date()),4))
age = age - 1
end if

end function

When there is a date in the date field, it works fine. When no date is entered, it shows the number 6719.

Any ideas why this occurs or how I can change the script so the field is blank if no date is entered?

Thanks much,

kenn

[Tom Cone Jr]

RE: Age Expression Help

Ken,

I don't think it's good practice to build such a test into the function itself. The parameters of the function tell the function to expect a valid date value will be passed to it. Unpredictable results will occur if you pass a different type of value or if you pass a blank value.

The script which uses the Age function should test the value of the DOB field before calling the function. If it's blank, the script should branch to another routine. For example it might pop up a ui_msg_box to alert the user.

Because DBF files use a fixed width format, empty fields are not really empty. They're filled with blanks. Perhaps your blank DOB field is being passed to the age function and that may be what's causing the odd results you're getting.

-- tom

[forskare]

RE: Age Expression Help

Tom,

Thanks for your advice. A ui_msg_box may be in order.

kenn

[JerryBrightbill]

RE: Age Expression Help

Ken

To follow up on Tom's suggestion, it is a good practice to give the function a default value and also test the value in the passed parameter for a valid value. For example:

function Age as N(DOB as D)
age = 0

if alltrim(cdate(DOB))=""
exit function
end if
'--- You may want to see if the date of birth is after the current date

if dob > date()
exit function
end if

Age = year(date())-year(DOB)
if val(right(cdate(DOB),4)) > val(right(cdate(date()),4))
age = age - 1
end if

end function

Jerry

[forskare]

RE: Age Expression Help

Jerry,

Thanks for the suggestion. I'll give it a try when I return home.

kenn