In the realm of legacy programming languages, COBOL is a stalwart that continues to play a key role in many enterprise computing environments. One of the common tasks when dealing with COBOL is handling dates, especially future dates. This involves achieving proficiency not just in basic COBOL programming but also to understand how dates in the future are calculated and manipulated within its ecosystem. This article delves into how future date calculation can be executed in an illustrative and comprehensive manner in COBOL.
Given a date, the objective is to find a date that will fall after a given number of days. It is essential to take care of different scenarios arising out of varying number of days in different months and also considering leap years while calculating the future date.
IDENTIFICATION DIVISION.
PROGRAM-ID. FutureDate.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 ws-date pic 9(8).
01 ws-future-days pic 9(4).
01 ws-future-date pic 9(8).
PROCEDURE DIVISION.
ACCEPT ws-date.
ACCEPT ws-future-days.
COMPUTE ws-future-date = FUNCTION INTEGER-OF-DATE (ws-date)
+ ws-future-days.
DISPLAY FUNCTION DATE-OF-INTEGER (ws-future-date).
STOP RUN.
Understanding the Code
Getting to grips with the sections of this COBOL program is beneficial to understand how future date calculation functions in action.
In the first section, we DECLARE the variables ws-date to accept the current date, ws-future-days to accept the number of days to calculate the future date, and ws-future-date to hold the future date. In the `PROCEDURE DIVISION`, we ACCEPT the current date and number of days from the user.
Following this, we compute the future date. COBOL provides built-in functions like `FUNCTION INTEGER-OF-DATE` and `FUNCTION DATE-OF-INTEGER` for date calculations. `FUNCTION INTEGER-OF-DATE` converts a date to an integer. We then add the number of days to this integer. Subsequently, `FUNCTION DATE-OF-INTEGER` converts this integer back to a date format.
COBOL Built-in Date Functions
It’s worthwhile gaining insights about COBOL’s date functions that perform an essential role in performing date calculations efficiently in programs.
COBOL provides several built-in functions specifically designed for date manipulations and computations. Notably, `FUNCTION INTEGER-OF-DATE` and `FUNCTION DATE-OF-INTEGER` are two such functions which are being used in our date calculation program. These functions offer a seamless and efficient way to handle dates in your COBOL application, saving you the trouble of writing complex logic to deal with different date formats and leap year scenarios.
COBOL’s date-handling functions, complement the language’s proven robustness and efficiency, lending it the necessary prowess to manage modern, real-world scenarios which require date manipulation tasks including calculating future dates.
