[mdlug] I asked Grok 3 to create a COBOL program

[Gib]

The MUG group had a meeting this week with this topic:

There’s a programming website called Advent of Code:
https://adventofcode.com.

It’s an Advent calendar of 25 small programming puzzles for a variety of
skill
sets and levels that can be solved in any programming language you like.

You can see the first puzzle at https://adventofcode.com/2024/day/1.

I asked Grok 3 to create a COBOL program.
This took just a few seconds.

Here was the prompt:
Create the source code in COBOL to read a file that contains two columns of
numbers and displays the difference of the sums of the two columns.

The result:

Here's a COBOL program that reads a file with two columns of numbers and
calculates the difference between their sums:

cobol

       IDENTIFICATION DIVISION.       PROGRAM-ID. COLUMN-DIFFERENCE.
           ENVIRONMENT DIVISION.       INPUT-OUTPUT SECTION.
FILE-CONTROL.           SELECT INPUT-FILE               ASSIGN TO
"INPUTNUM.TXT"               ORGANIZATION IS LINE SEQUENTIAL.
        DATA DIVISION.       FILE SECTION.       FD  INPUT-FILE.
01  INPUT-RECORD.           05  COLUMN-1     PIC 9(5)V99.           05
 FILLER       PIC X.           05  COLUMN-2     PIC 9(5)V99.
       WORKING-STORAGE SECTION.       01  SUMS.           05
SUM-COL-1    PIC 9(7)V99 VALUE 0.           05  SUM-COL-2    PIC
9(7)V99 VALUE 0.           05  DIFFERENCE   PIC S9(7)V99 VALUE 0.
            01  EOF-FLAG         PIC X VALUE "N".           88
END-OF-FILE         VALUE "Y".                  PROCEDURE DIVISION.
   MAIN-LOGIC.           PERFORM INITIALIZE-PROGRAM           PERFORM
PROCESS-FILE           PERFORM CALCULATE-AND-DISPLAY           PERFORM
TERMINATE-PROGRAM           STOP RUN.
INITIALIZE-PROGRAM.           OPEN INPUT INPUT-FILE           DISPLAY
"Processing file...".                  PROCESS-FILE.           PERFORM
UNTIL END-OF-FILE               READ INPUT-FILE                   AT
END                       SET END-OF-FILE TO TRUE
NOT AT END                       ADD COLUMN-1 TO SUM-COL-1
          ADD COLUMN-2 TO SUM-COL-2               END-READ
END-PERFORM.                  CALCULATE-AND-DISPLAY.           COMPUTE
DIFFERENCE = SUM-COL-1 - SUM-COL-2           DISPLAY "Sum of Column 1:
" SUM-COL-1           DISPLAY "Sum of Column 2: " SUM-COL-2
DISPLAY "Difference (Col1 - Col2): " DIFFERENCE.
TERMINATE-PROGRAM.           CLOSE INPUT-FILE           DISPLAY
"Processing complete.".

This COBOL program:

   1. Defines an input file "INPUTNUM.TXT" with two columns of numbers
   (each 5 digits with 2 decimal places)
   2. Creates variables to store the sums and difference
   3. Opens and reads the file line by line
   4. Accumulates sums for each column
   5. Calculates the difference between the sums
   6. Displays the results

The expected input file format (INPUTNUM.TXT) should look like this:

12345.67 89012.3423456.78 34567.89
34567.89 12345.67


   - Two columns separated by a space
   - Numbers can include decimals
   - Each line represents one record

Key features:

   - Uses LINE SEQUENTIAL organization for simple text file reading
   - Includes error handling for end-of-file
   - Uses PIC clauses to define number formats
   - Displays formatted output

To use this program:

   1. Create a text file named "INPUTNUM.TXT" with your numbers
   2. Compile and run the program
   3. Check the output for the sums and difference

The program assumes:

   - Numbers are non-negative
   - Input file exists in the same directory
   - Numbers fit within the defined picture clauses (7 digits total, 2
   after decimal)