[mdlug] [Discuss] I asked Grok 3 to create a COBOL program
Gib
gibmaxn at gmail.com
Fri Mar 14 10:24:49 EDT 2025
I used GNUCOBOL. I asked Grok 3 how to install and run COBOL program in
Ubuntu 24.04.
Here is the prompt and response:
How can I compile and run a COBOL program on Ubuntu Linux 24.04?
Compiling and running a COBOL program on Ubuntu Linux 24.04 is
straightforward once you set up the necessary tools. Here's a step-by-step
guide:
1. Install a COBOL Compiler
Ubuntu doesn’t come with a COBOL compiler pre-installed, so you’ll need
to install one. The most common open-source COBOL compiler is
GnuCOBOL (formerly
OpenCOBOL). Here’s how to install it:
- Open a terminal.
- Update the package list:
bash
sudo apt update
- Install GnuCOBOL:
bash
sudo apt install gnucobol
This installs the cobc compiler, which translates COBOL code into
executable programs.
- Verify the installation:
bash
cobc --version
You should see the version of GnuCOBOL installed (e.g., GnuCOBOL 3.1.2 or
similar).
2. Write a Simple COBOL Program
Create a file with a .cob or .cbl extension. For example, let’s write a
"Hello, World!" program.
- Open a text editor (e.g., nano, vim, or any IDE):
bash
nano hello.cob
- Enter the following COBOL code:
cobol
IDENTIFICATION DIVISION.PROGRAM-ID. HelloWorld.PROCEDURE
DIVISION. DISPLAY "Hello, World!". STOP RUN.
- Save the file and exit (Ctrl+O, Enter, Ctrl+X in nano).
3. Compile the COBOL Program
Use the cobc compiler to compile your COBOL source code into an
executable:
- In the terminal, run:
bash
cobc -x hello.cob
- The -x flag tells cobc to generate an executable program (as
opposed to just an object file).
- If there are no syntax errors, this will produce an executable
file named hello in the same directory.
4. Run the Program
Execute the compiled program:
- Run:
bash
./hello
- Output:
Hello, World!
5. Troubleshooting (Optional)
- Errors during compilation: If you get syntax errors, double-check your
COBOL code. COBOL is sensitive to spacing and indentation
(though GnuCOBOL
is more forgiving than traditional compilers).
- Missing compiler: If cobc isn’t found, ensure GnuCOBOL installed
correctly (sudo apt install gnucobol).
On Fri, Mar 14, 2025 at 8:03 AM Jim McQuillan <jam at mcquil.com> wrote:
> Based on what I know about COBOL (I programmed in COBOL for over 20 years)
> I think that record format still isn't going to work.
> PIC 9(5)
> PIC x(2)
> PIC 9(5)
>
> A PIC 9(5) is going to look for a 5-digit number that may be space padded
> but still will take up 5 positions.
> So... a record with '1 2' isn't going to work.
> But.. you say you tried it so I could be wrong.
>
> The only way I can see to handle this variable length input would be
> something like:
>
>
> FILE SECTION.
> FD INPUT-FILE.
> 01 INPUT-RECORD PIC X(20).
> .
> .
> WORKING-STORAGE SECTION.
> 01 COL-1 PIC 9(5).
> 01 COL-2 PIC 9(5).
> .
> .
> PROCEDURE DIVISION.
>
> UNSTRING INPUT-RECORD DELIMITED BY SPACES
> INTO COL-1
> COL-2.
>
>
> Although, it's been a long time since I touched COBOL so there may be
> other ways. And I'm not sure if a PIC 9 field can be the destination for
> an UNSTRING.
>
>
> What cobol compiler did you use? I'd like to give it a try myself.
>
> Jim.
>
> On Fri, Mar 14, 2025 at 8:39 AM Gib <gibmaxn at gmail.com> wrote:
>
>> I compiled and ran the program with your example data and the example
>> data provided by Grok 3. The results are interesting. But I would say it
>> is correct given the instructions.
>>
>> With your file:
>> Processing file...
>> Sum of Column 1: 0000081267
>> Sum of Column 2: 0000004415
>> Difference (Col1 - Col2): +0000076852
>> Processing complete.
>> gib at gib-VMware-Virtual-Platform:~$ cat INPUTVAR.TXT
>> 39472 15292
>> 41795 28867
>> Note: your example file has three spaces between the columns not 2.
>> So, the rightmost digit of the second column is not used.
>> 1529 + 2886 = 4415
>>
>> With the file provided by Grok 3:
>> Processing file...
>> Sum of Column 1: 0000047745
>> Sum of Column 2: 0000213602
>> Difference (Col1 - Col2): -0000165857
>> Processing complete.
>> gib at gib-VMware-Virtual-Platform:~$ cat INPUTVAR.TXT
>> 12345 67890
>> 234 567
>> 12 89012
>>
>> Note: the left justified space filled on the right is interpreted as if
>> it is a five digit number.
>> 234 = 23400
>> 567 = 56700
>> 12 = 12000
>>
>> On Thu, Mar 13, 2025 at 3:56 PM Gib <gibmaxn at gmail.com> wrote:
>>
>>> Okay, I think this will work with your example file.
>>> It took me longer to describe what I wanted than for Grok 3 to create
>>> the code.
>>> I've never tried using a pic 9(5) to read data that was left justified
>>> and space filled on the right.
>>>
>>> 01 INPUT-RECORD.
>>> 05 COLUMN-1 PIC 9(5).
>>> 05 FILLER PIC XX.
>>> 05 COLUMN-2 PIC 9(5).
>>>
>>>
>>> Input record definition:
>>>
>>> - COLUMN-1 uses PIC 9(5) for up to 5 digits
>>> - FILLER PIC XX defines two spaces between columns
>>> - COLUMN-2 uses PIC 9(5) for up to 5 digits
>>>
>>>
>>>
>>> Expected input file format (INPUTVAR.TXT):
>>>
>>> 12345 67890234 567
>>> 12 89012
>>>
>>>
>>> - Two columns separated by exactly two spaces
>>> - Each number can be 1 to 5 digits (1-99999)
>>> - Numbers should be right-aligned in their 5-digit field
>>> - Each line represents one record
>>>
>>> Notes:
>>>
>>> - The program assumes numbers are padded with leading zeros or
>>> spaces if less than 5 digits
>>> - Maximum value per number is 99999
>>> - Sums can handle up to 10 digits (9999999999)
>>> - No decimal points allowed
>>> - File must have exactly two spaces between numbers
>>>
>>>
>>> On Thu, Mar 13, 2025 at 2:44 PM Jim McQuillan <jam at mcquil.com> wrote:
>>>
>>>> That still won't work.
>>>>
>>>> The sample file is 1-digit codes with 2 spaces between them.
>>>> The real file could be any number of digits
>>>>
>>>> here's the first 2 lines of my real data file:
>>>>
>>>> 39472 15292
>>>> 41795 28867
>>>>
>>>> See if you can get it to handle any number of digits. or at least 1
>>>> digit or 5 digit.
>>>> If AI can make COBOL do that, then I'll be impressed.
>>>>
>>>> Jim.
>>>>
>>>>
>>>>
>>>> On Thu, Mar 13, 2025 at 2:03 PM Gib <gibmaxn at gmail.com> wrote:
>>>>
>>>>> Yup. Easy to update the code with a simple request that just took a
>>>>> few seconds. The text that I provided was this:
>>>>>
>>>>> The input file format is two columns consisting of one digit each.
>>>>> Create another version of the source code with input of two single digits
>>>>> as input.
>>>>>
>>>>> The only change was the definition of the input file format:
>>>>>
>>>>> 01 INPUT-RECORD.
>>>>> 05 COLUMN-1 PIC 9.
>>>>> 05 FILLER PIC X.
>>>>> 05 COLUMN-2 PIC 9.
>>>>>
>>>>>
>>>>> On Thu, Mar 13, 2025 at 9:56 AM Jim McQuillan <jam at mcquil.com> wrote:
>>>>>
>>>>>> Gib,
>>>>>>
>>>>>> That's interesting but it's not actually going to work, given the
>>>>>> data files from Advent of code.
>>>>>>
>>>>>> It's expecting the input to look like rows of:
>>>>>> 9999999 9999999
>>>>>>
>>>>>> It would choke on the sample data file:
>>>>>> 3 4
>>>>>> 4 3
>>>>>> 2 5
>>>>>> 1 3
>>>>>> 3 9
>>>>>> 3 3
>>>>>>
>>>>>> With an input record specification of:
>>>>>> 01 INPUT-RECORD.
>>>>>> 05 COLUMN-1 PIC 9(5)V99.
>>>>>> 05 FILLER PIC X.
>>>>>> 05 COLUMN-2 PIC 9(5)V99.
>>>>>>
>>>>>> The sample data would have to look like:
>>>>>> 0000300 0000400
>>>>>> 0000300 0000300
>>>>>> 0000200 0000500
>>>>>> 0000100 0000300
>>>>>> 0000300 0000900
>>>>>> 0000300 0000300
>>>>>>
>>>>>> The difficult thing with COBOL is dealing with data that doesn't
>>>>>> strictly adhere to a rigid format.
>>>>>>
>>>>>> You'd have to use something like 'UNSTRING' to take a string of
>>>>>> numbers delimited by varying amounts of whitespace.
>>>>>>
>>>>>> I think it would be very cool if you could carry on a conversation
>>>>>> with Grok 3, continually refining the specifications until you get
>>>>>> something that actually solves the problem, both for the sample data set
>>>>>> and then a real data set.
>>>>>>
>>>>>> Then... compare how long it took, versus just sitting down and
>>>>>> writing the program yourself.
>>>>>>
>>>>>> My fear is that management is starting to believe that AI is ready to
>>>>>> replace real programmers without realizing that every line of code produced
>>>>>> by AI needs to be looked at very carefully to make sure it's actually doing
>>>>>> the right thing.
>>>>>>
>>>>>> Jim.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Thu, Mar 13, 2025 at 10:32 AM Gib <gibmaxn at gmail.com> wrote:
>>>>>>
>>>>>>> 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)
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Sponsors:
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>>>>>>> services for MUG.org
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>>>>>>> Science fiction and more
>>>>>>>
>>>>>>> Discuss mailing list
>>>>>>> http://mug.org/mailman/listinfo/discuss_mug.org
>>>>>>>
>>>>>> _______________________________________________
>>>>>> Sponsors:
>>>>>> http://a2hosting.com a2hosting - proudly providing web hosting
>>>>>> services for MUG.org
>>>>>> http://altair.com Altair - Altair transforms products and orgs via
>>>>>> simulation, optimization and HPC
>>>>>> http://www.avairis.com Avairis, Inc. - Web based medical practice
>>>>>> management systems
>>>>>> http://www.penguicon.org Penguicon - Annual convention for Linux,
>>>>>> Science fiction and more
>>>>>>
>>>>>> Discuss mailing list
>>>>>> http://mug.org/mailman/listinfo/discuss_mug.org
>>>>>>
>>>>> _______________________________________________
>>>>> Sponsors:
>>>>> http://a2hosting.com a2hosting - proudly providing web hosting
>>>>> services for MUG.org
>>>>> http://altair.com Altair - Altair transforms products and orgs via
>>>>> simulation, optimization and HPC
>>>>> http://www.avairis.com Avairis, Inc. - Web based medical practice
>>>>> management systems
>>>>> http://www.penguicon.org Penguicon - Annual convention for Linux,
>>>>> Science fiction and more
>>>>>
>>>>> Discuss mailing list
>>>>> http://mug.org/mailman/listinfo/discuss_mug.org
>>>>>
>>>> _______________________________________________
>>>> Sponsors:
>>>> http://a2hosting.com a2hosting - proudly providing web hosting
>>>> services for MUG.org
>>>> http://altair.com Altair - Altair transforms products and orgs via
>>>> simulation, optimization and HPC
>>>> http://www.avairis.com Avairis, Inc. - Web based medical practice
>>>> management systems
>>>> http://www.penguicon.org Penguicon - Annual convention for Linux,
>>>> Science fiction and more
>>>>
>>>> Discuss mailing list
>>>> http://mug.org/mailman/listinfo/discuss_mug.org
>>>>
>>> _______________________________________________
>> Sponsors:
>> http://a2hosting.com a2hosting - proudly providing web hosting services
>> for MUG.org
>> http://altair.com Altair - Altair transforms products and orgs via
>> simulation, optimization and HPC
>> http://www.avairis.com Avairis, Inc. - Web based medical practice
>> management systems
>> http://www.penguicon.org Penguicon - Annual convention for Linux,
>> Science fiction and more
>>
>> Discuss mailing list
>> http://mug.org/mailman/listinfo/discuss_mug.org
>>
> _______________________________________________
> Sponsors:
> http://a2hosting.com a2hosting - proudly providing web hosting services
> for MUG.org
> http://altair.com Altair - Altair transforms products and orgs via
> simulation, optimization and HPC
> http://www.avairis.com Avairis, Inc. - Web based medical practice
> management systems
> http://www.penguicon.org Penguicon - Annual convention for Linux, Science
> fiction and more
>
> Discuss mailing list
> http://mug.org/mailman/listinfo/discuss_mug.org
>
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