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COBOL Date Time Handling

Date and time handling in COBOL involves obtaining current date/time, formatting dates for display, performing date calculations, validating dates, and working with various date formats. COBOL provides functions like CURRENT-DATE and ACCEPT FROM DATE/TIME to get system date and time, and you use string manipulation and arithmetic to format, calculate, and validate dates. Effective date/time handling is essential for business applications that need timestamps, age calculations, date-based reporting, and temporal data processing.

Getting Current Date and Time

Using CURRENT-DATE Function

CURRENT-DATE is the most comprehensive way to get current date and time:

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       WORKING-STORAGE SECTION.
       01  CURRENT-DATE-TIME        PIC X(21).
       
       PROCEDURE DIVISION.
       GET-CURRENT-DATE-TIME.
           MOVE FUNCTION CURRENT-DATE TO CURRENT-DATE-TIME
           
           *> CURRENT-DATE returns: YYYYMMDDHHMMSSssssss+HHMM
           *> Example: "20240115143045234567+0500"
           *>          2024-01-15 14:30:45.234567 +05:00
           
           DISPLAY 'Current date/time: ' CURRENT-DATE-TIME
           
           STOP RUN.

CURRENT-DATE format breakdown:

  • Positions 1-4: Year (YYYY)
  • Positions 5-6: Month (MM, 01-12)
  • Positions 7-8: Day (DD, 01-31)
  • Positions 9-10: Hour (HH, 00-23)
  • Positions 11-12: Minute (MM, 00-59)
  • Positions 13-14: Second (SS, 00-59)
  • Positions 15-20: Microseconds (ssssss)
  • Positions 21: Sign (+ or -)
  • Positions 22-25: Timezone offset (HHMM)

Using ACCEPT FROM DATE

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       WORKING-STORAGE SECTION.
       01  CURRENT-DATE-YYYYMMDD    PIC 9(8).
       01  CURRENT-DATE-YYMMDD      PIC 9(6).
       
       PROCEDURE DIVISION.
       GET-DATE-ONLY.
           *> Get date in YYYYMMDD format
           ACCEPT CURRENT-DATE-YYYYMMDD FROM DATE YYYYMMDD
           *> Result: 20240115
           
           *> Get date in YYMMDD format (2-digit year)
           ACCEPT CURRENT-DATE-YYMMDD FROM DATE YYMMDD
           *> Result: 240115
           
           DISPLAY 'Date (YYYYMMDD): ' CURRENT-DATE-YYYYMMDD
           DISPLAY 'Date (YYMMDD): ' CURRENT-DATE-YYMMDD
           
           STOP RUN.

Using ACCEPT FROM TIME

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       WORKING-STORAGE SECTION.
       01  CURRENT-TIME             PIC 9(8).
       
       PROCEDURE DIVISION.
       GET-TIME-ONLY.
           *> Get time in HHMMSS format
           ACCEPT CURRENT-TIME FROM TIME
           *> Result: 143045 (2:30:45 PM)
           
           DISPLAY 'Current time: ' CURRENT-TIME
           
           STOP RUN.

Extracting Date Components

Use reference modification to extract date parts:

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       WORKING-STORAGE SECTION.
       01  CURRENT-DATE-TIME        PIC X(21).
       01  DATE-YYYYMMDD            PIC 9(8).
       01  YEAR                     PIC 9(4).
       01  MONTH                    PIC 9(2).
       01  DAY                      PIC 9(2).
       01  HOUR                     PIC 9(2).
       01  MINUTE                   PIC 9(2).
       01  SECOND                   PIC 9(2).
       
       PROCEDURE DIVISION.
       EXTRACT-COMPONENTS.
           MOVE FUNCTION CURRENT-DATE TO CURRENT-DATE-TIME
           
           *> Extract date portion (YYYYMMDD)
           MOVE CURRENT-DATE-TIME(1:8) TO DATE-YYYYMMDD
           
           *> Extract individual components
           MOVE CURRENT-DATE-TIME(1:4) TO YEAR      *> 2024
           MOVE CURRENT-DATE-TIME(5:2) TO MONTH     *> 01
           MOVE CURRENT-DATE-TIME(7:2) TO DAY      *> 15
           MOVE CURRENT-DATE-TIME(9:2) TO HOUR    *> 14
           MOVE CURRENT-DATE-TIME(11:2) TO MINUTE  *> 30
           MOVE CURRENT-DATE-TIME(13:2) TO SECOND  *> 45
           
           DISPLAY 'Year: ' YEAR
           DISPLAY 'Month: ' MONTH
           DISPLAY 'Day: ' DAY
           DISPLAY 'Time: ' HOUR ':' MINUTE ':' SECOND
           
           STOP RUN.

Formatting Dates

Format dates for display using STRING or reference modification:

Format as MM/DD/YYYY

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       WORKING-STORAGE SECTION.
       01  DATE-YYYYMMDD            PIC 9(8).
       01  FORMATTED-DATE           PIC X(10).
       01  YEAR                     PIC 9(4).
       01  MONTH                    PIC 9(2).
       01  DAY                      PIC 9(2).
       
       PROCEDURE DIVISION.
       FORMAT-US-STYLE.
           ACCEPT DATE-YYYYMMDD FROM DATE YYYYMMDD
           
           *> Extract components
           MOVE DATE-YYYYMMDD(1:4) TO YEAR
           MOVE DATE-YYYYMMDD(5:2) TO MONTH
           MOVE DATE-YYYYMMDD(7:2) TO DAY
           
           *> Build MM/DD/YYYY format
           STRING MONTH DELIMITED BY SIZE
                  '/' DELIMITED BY SIZE
                  DAY DELIMITED BY SIZE
                  '/' DELIMITED BY SIZE
                  YEAR DELIMITED BY SIZE
                  INTO FORMATTED-DATE
           END-STRING
           
           DISPLAY 'Formatted date: ' FORMATTED-DATE
           *> Output: 01/15/2024
           
           STOP RUN.

Format as DD-MM-YYYY

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       PROCEDURE DIVISION.
       FORMAT-EUROPEAN-STYLE.
           ACCEPT DATE-YYYYMMDD FROM DATE YYYYMMDD
           
           MOVE DATE-YYYYMMDD(1:4) TO YEAR
           MOVE DATE-YYYYMMDD(5:2) TO MONTH
           MOVE DATE-YYYYMMDD(7:2) TO DAY
           
           *> Build DD-MM-YYYY format
           STRING DAY DELIMITED BY SIZE
                  '-' DELIMITED BY SIZE
                  MONTH DELIMITED BY SIZE
                  '-' DELIMITED BY SIZE
                  YEAR DELIMITED BY SIZE
                  INTO FORMATTED-DATE
           END-STRING
           
           DISPLAY 'Formatted date: ' FORMATTED-DATE
           *> Output: 15-01-2024
           
           STOP RUN.

Date Validation

Validate dates to ensure they're correct:

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       WORKING-STORAGE SECTION.
       01  INPUT-DATE              PIC 9(8).
       01  YEAR                     PIC 9(4).
       01  MONTH                    PIC 9(2).
       01  DAY                      PIC 9(2).
       01  VALID-DATE-FLAG          PIC X VALUE 'Y'.
           88  VALID-DATE          VALUE 'Y'.
           88  INVALID-DATE        VALUE 'N'.
       
       PROCEDURE DIVISION.
       VALIDATE-DATE.
           *> Assume INPUT-DATE contains YYYYMMDD format
           MOVE INPUT-DATE(1:4) TO YEAR
           MOVE INPUT-DATE(5:2) TO MONTH
           MOVE INPUT-DATE(7:2) TO DAY
           
           *> Check if date is numeric
           IF INPUT-DATE IS NOT NUMERIC
               SET INVALID-DATE TO TRUE
           ELSE
               *> Check month range
               IF MONTH < 1 OR MONTH > 12
                   SET INVALID-DATE TO TRUE
               ELSE
                   *> Check day range based on month
                   PERFORM CHECK-DAY-VALIDITY
               END-IF
           END-IF
           
           IF VALID-DATE
               DISPLAY 'Date is valid'
           ELSE
               DISPLAY 'ERROR: Invalid date'
           END-IF
           
           STOP RUN.
       
       CHECK-DAY-VALIDITY.
           *> Check day based on month
           EVALUATE MONTH
               WHEN 1 3 5 7 8 10 12
                   *> Months with 31 days
                   IF DAY < 1 OR DAY > 31
                       SET INVALID-DATE TO TRUE
                   END-IF
               WHEN 4 6 9 11
                   *> Months with 30 days
                   IF DAY < 1 OR DAY > 30
                       SET INVALID-DATE TO TRUE
                   END-IF
               WHEN 2
                   *> February - check for leap year
                   PERFORM CHECK-FEBRUARY-DAY
           END-EVALUATE.
       
       CHECK-FEBRUARY-DAY.
           IF FUNCTION MOD(YEAR, 4) = 0
              AND FUNCTION MOD(YEAR, 100) NOT = 0
              OR FUNCTION MOD(YEAR, 400) = 0
               *> Leap year - allow day 29
               IF DAY < 1 OR DAY > 29
                   SET INVALID-DATE TO TRUE
               END-IF
           ELSE
               *> Not leap year - max day 28
               IF DAY < 1 OR DAY > 28
                   SET INVALID-DATE TO TRUE
               END-IF
           END-IF.

Leap Year Handling

A year is a leap year if it's divisible by 4, except century years which must be divisible by 400:

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       WORKING-STORAGE SECTION.
       01  YEAR                     PIC 9(4).
       01  IS-LEAP-YEAR-FLAG       PIC X.
           88  IS-LEAP-YEAR        VALUE 'Y'.
           88  NOT-LEAP-YEAR       VALUE 'N'.
       
       PROCEDURE DIVISION.
       CHECK-LEAP-YEAR.
           *> Leap year if: (divisible by 4 AND not century)
           *>            OR (divisible by 400)
           IF (FUNCTION MOD(YEAR, 4) = 0
              AND FUNCTION MOD(YEAR, 100) NOT = 0)
              OR FUNCTION MOD(YEAR, 400) = 0
               SET IS-LEAP-YEAR TO TRUE
               DISPLAY YEAR ' is a leap year'
           ELSE
               SET NOT-LEAP-YEAR TO TRUE
               DISPLAY YEAR ' is not a leap year'
           END-IF
           
           STOP RUN.

Date Calculations

Adding Days to a Date

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       WORKING-STORAGE SECTION.
       01  START-DATE               PIC 9(8) VALUE 20240115.
       01  DAYS-TO-ADD              PIC 9(4) VALUE 30.
       01  RESULT-DATE              PIC 9(8).
       01  YEAR                     PIC 9(4).
       01  MONTH                    PIC 9(2).
       01  DAY                      PIC 9(2).
       
       PROCEDURE DIVISION.
       ADD-DAYS.
           *> Simple approach: add days and handle overflow
           *> Note: This is simplified - full implementation
           *> needs to handle month/year boundaries
           
           MOVE START-DATE(1:4) TO YEAR
           MOVE START-DATE(5:2) TO MONTH
           MOVE START-DATE(7:2) TO DAY
           
           ADD DAYS-TO-ADD TO DAY
           
           *> Handle day overflow (simplified)
           *> Full implementation would check month lengths
           *> and handle year boundaries
           
           *> Build result date
           COMPUTE RESULT-DATE = YEAR * 10000 
                                + MONTH * 100 
                                + DAY
           
           DISPLAY 'Start date: ' START-DATE
           DISPLAY 'Days to add: ' DAYS-TO-ADD
           DISPLAY 'Result date: ' RESULT-DATE
           
           STOP RUN.

Common Date Formats

Common COBOL Date Formats
FormatExampleCommon Use
YYYYMMDD20240115Most common, sortable, compact
MM/DD/YYYY01/15/2024US display format
DD/MM/YYYY15/01/2024European display format
YYYY-MM-DD2024-01-15ISO-like format with separators
YYMMDD240115Legacy 2-digit year format

Best Practices

Follow these best practices:

  • Use YYYYMMDD: Most reliable format for storage and sorting
  • Always validate: Check dates before using in calculations
  • Handle leap years: Account for February 29 in leap years
  • Document formats: Clearly document date format assumptions
  • Use functions: Prefer CURRENT-DATE and ACCEPT FROM DATE over manual date entry
  • Test edge cases: Test month boundaries, year boundaries, leap years

Explain Like I'm 5: Date Time Handling

Think of date/time handling like reading a clock and calendar:

  • CURRENT-DATE is like asking "what time and date is it right now?"
  • Extracting components is like reading just the hour, or just the day
  • Formatting is like writing the date in different ways (1/15/2024 vs 15-01-2024)
  • Validation is like checking if a date makes sense (no February 30th!)
  • Leap years are like the special year that has an extra day in February

Just like you can read a clock to get the time, COBOL can get the current date/time and work with it!

Test Your Knowledge

1. What does CURRENT-DATE return?

  • Just the date
  • A 21-character string with date, time, and timezone
  • Just the time
  • A numeric value

2. How do you extract the year from a YYYYMMDD date?

  • DATE(1:4)
  • DATE(1:2)
  • DATE(5:4)
  • DATE(7:2)

3. What is the most common date format in mainframe COBOL?

  • MM/DD/YYYY
  • YYYYMMDD
  • DD-MM-YYYY
  • YYYY-MM-DD

4. How do you get just the current date (not time)?

  • Use CURRENT-DATE and extract first 8 characters
  • Use ACCEPT FROM DATE YYYYMMDD
  • Both of the above
  • Use a special DATE function

5. What makes a year a leap year?

  • Divisible by 4
  • Divisible by 4, except centuries which must be divisible by 400
  • Divisible by 100
  • Every 4 years regardless

6. How do you format a date as MM/DD/YYYY?

  • Use a special FORMAT function
  • Extract components and use STRING to build the format
  • COBOL cannot format dates
  • Use PICTURE editing

Related Concepts

Related Concepts

Date Functions

Learn about COBOL date functions

STRING Statement

Understanding string building for date formatting

Reference Modification

Using reference modification to extract date parts

Data Validation

Validating date formats and values

Related Pages