The r-conc.p procedure prints mailing labels. It uses the concatenation operator (+) to ensure that the third line of each label shows the city and state separated by a comma and a space. The FORMAT x(16) is specified to provide room for up to 16 characters in the result of the concatenation. If a FORMAT is not given, then the AVM displays only the first eight characters of the result since x(8) is the default format for a character expression.
If any of the string values you concatenate is the Unknown value (
?), then the result is the Unknown value (
?). This might lead to unexpected results if a field used in an expression is not mandatory. For example, you might have fields for a person’s first name, last name, and middle initial. You might combine these into a full name with an expression like the following:
If minit is not a mandatory field, it might be set to the Unknown value (
?) in some records. If so, then those records are displayed as the Unknown value (
?). You can avoid this by using conditional code. For example: