The INTEGER-OF-DATE function converts a date in the
Gregorian calendar from standard date form (YYYYMMDD) to integer date form.
The function type is integer.
The function result is a seven-digit integer with a range from 1 to 3,067,671.

Format
>>-FUNCTION INTEGER-OF-DATE--(--argument-1--)------------------><
- argument-1
- Must be an integer of the form YYYYMMDD, whose value is obtained from the calculation
(YYYY * 10,000) + (MM * 100) + DD, where:
- YYYY represents the year in the Gregorian calendar. It must be an integer greater
than 1600, but not greater than 9999.
- MM represents a month and must be a positive integer less than 13.
- DD represents a day and must be a positive integer less than 32, provided that it is
valid for the specified month and year combination.
The returned value is an integer that is the number of days that the date represented
by argument-1 succeeds December 31, 1600 in the Gregorian calendar.
The INTDATE compiler option affects the starting date for the
integer date functions. For details, see the Enterprise COBOL Programming Guide.