A variable represents a specific data
item, or value, and acts as a placeholder for that value. When a formula
encounters a variable, the formula searches for the value of the variable and
uses it in the formula. Unlike a constant value, which is fixed and unchanging,
a variable can be repeatedly assigned different values. You assign a value to a
variable and the variable maintains the value until you later assign a new
value. Because of this flexibility, it is necessary for you to declare
variables before you use them so that
Crystal Reports is aware of them and understands how you
intend to use them.
Example
If you wanted to report on customers by
area code, you could create a variable that extracts the area code from a
customer fax number. The following is an example of a variable called
areaCode:
Local StringVar areaCode;
areaCode := {Customer.Fax} [1 To 3];
The first line of the variable example
is the variable declaration; it gives the variable a name and type. The
database field {Customer.Fax} is a String field and [1 To 3] extracts the first
three characters from its current value. The variable areaCode is then assigned
this value.