COBOL Code Explanation examples
For a selected COBOL source code, the code explanation service provides three levels of code explanation: Simple, Detailed, and Guided.
Examples
Given here is an example for the different levels of AI-generated explanations from watsonx Code Assistant™ for Z using the following paragraph of COBOL code.
Example: Selected COBOL paragraph
100-PROCESS-TRANSACTIONS.
PERFORM 710-READ-TRAN-FILE.
IF WS-TRAN-EOF NOT = 'Y'
COMPUTE NUM-TRAN-RECS = NUM-TRAN-RECS + 1
MOVE 'Y' TO WS-TRAN-OK
IF TRAN-KEY < WS-PREV-TRAN-KEY AND TRAN-COMMENT NOT = '*'
MOVE 'TRANSACTION OUT OF SEQUENCE' TO ERR-MSG-DATA1
MOVE SPACES TO ERR-MSG-DATA2
PERFORM 299-REPORT-BAD-TRAN
ELSE
EVALUATE TRAN-CODE
WHEN 'UPDATE'
PERFORM 200-PROCESS-UPDATE-TRAN
WHEN 'ADD '
PERFORM 210-PROCESS-ADD-TRAN
WHEN 'DELETE'
PERFORM 220-PROCESS-DELETE-TRAN
WHEN OTHER
IF TRAN-COMMENT NOT = '*'
MOVE 'INVALID TRAN CODE:' TO ERR-MSG-DATA1
MOVE TRAN-CODE TO ERR-MSG-DATA2
PERFORM 299-REPORT-BAD-TRAN
END-IF
END-EVALUATE
END-IF
MOVE TRAN-KEY TO WS-PREV-TRAN-KEY
IF WS-TRAN-OK = 'Y'
PERFORM 830-REPORT-TRAN-PROCESSED
END-IF
END-IF.
Example 1: Simple COBOL explanation
Summary:
This paragraph reads a transaction record from the input file, and processes it based on the transaction code. It also checks for out-of-sequence transactions and reports any errors.
Input:
The input file is a sequential file containing transaction records. Each record contains information about a transaction, including the transaction code, key, and comment.
Output:
The output is a report that lists the transactions that were processed successfully, and any errors that were encountered.
Logic:
The paragraph starts by reading a transaction record from the input file. If the end of file has not been reached, the program continues with the processing steps.
The program increments a counter to keep track of the number of transactions that have been processed.
The program checks if the current transaction key is less than the previous transaction key. If it is, it reports an error message that the transactions are out of sequence.
Next, the program evaluates the transaction code to determine what action to take. If the code is "UPDATE", the program processes an update transaction. If the code is "ADD", the program processes an add transaction. If the code is "DELETE", the program processes a delete transaction. If the code is anything else, the program reports an error message if the transaction is not a comment.
After processing the transaction, the program moves the current transaction key to a previous transaction key variable, and reports a success message if the transaction was processed successfully.
Overall, this paragraph reads a transaction record from the input file, processes it based on the transaction code, and reports any errors or out-of-sequence transactions.
Example 2: Detailed COBOL
explanation
Business Purpose:
The COBOL paragraph is a part of a COBOL program that processes a transaction file. The program reads a transaction record from the file, processes the record based on the transaction code, and reports the results.
Inputs and Outputs:
The program takes a transaction file as input and produces a report as output. The transaction file contains records with the following fields: transaction key, transaction code, and transaction comment. The program reads the transaction key, code, and comment from the file and stores them in the appropriate variables.
The program also produces a report that lists the transaction keys and comments that were processed successfully. If a transaction is not processed successfully, the program reports the error and the transaction key and comment.
Functional Summary:
The paragraph starts by calling a subroutine to read the next transaction record from the file. If the end of the file has not been reached, the program continues with the processing steps.
The program increments a counter to keep track of the number of transactions processed. It then sets a flag to indicate that the transaction is valid (WS-TRAN-OK = 'Y').
If the transaction key is less than the previous transaction key and the transaction comment is not a comment record ('*'), the program reports a transaction out of sequence error.
Next, the program evaluates the transaction code. If the code is 'UPDATE', the program calls a subroutine to process the update transaction. If the code is 'ADD', the program calls a subroutine to process the add transaction. If the code is 'DELETE', the program calls a subroutine to process the delete transaction. If the code is anything else, and the transaction comment is not a comment record ('*'), the program reports an invalid transaction code error.
After processing the transaction, the program moves the transaction key to a variable to keep track of the previous transaction key. If the transaction was processed successfully (WS-TRAN-OK = 'Y'), the program reports the transaction as processed.
Overall, the paragraph reads a transaction record from the file, processes it based on the transaction code, and reports the results.
Example 3: Guided COBOL
explanation
Business Purpose:
The purpose of this code is to process a transaction file that contains transactions for updating, adding, and deleting customer records. The code reads each transaction record, validates the data, and performs the appropriate action based on the transaction code.
Structured Summary of the Code Logic:
1. Read the transaction file: The code reads the transaction file using a PERFORM statement. The PERFORM statement is followed by a reference to the 710-READ-TRAN-FILE procedure, which reads the next transaction record.
2. Check for end-of-file: The code checks if the end-of-file indicator WS-TRAN-EOF is set to 'Y'. If it is not, the code continues processing the transaction record.
3. Increment the transaction record count: The code increments the transaction record count NUM-TRAN-RECS by 1 using the COMPUTE statement.
4. Validate the transaction record: The code validates the transaction record by checking if the transaction key TRAN-KEY is less than the previous transaction key WS-PREV-TRAN-KEY. If the transaction key is out of sequence, the code sets the error message ERR-MSG-DATA1 to "Transaction out of sequence" and calls the 299-REPORT-BAD-TRAN procedure to report the error.
5. Process the transaction: The code processes the transaction based on the transaction code TRAN-CODE. If the transaction code is "UPDATE", the code calls the 200-PROCESS-UPDATE-TRAN procedure to update the customer record. If the transaction code is "ADD", the code calls the 210-PROCESS-ADD-TRAN procedure to add the customer record. If the transaction code is "DELETE", the code calls the 220-PROCESS-DELETE-TRAN procedure to delete the customer record. If the transaction code is invalid, the code checks if the transaction comment TRAN-COMMENT is not equal to "*", which indicates that the transaction is a comment. If the transaction is not a comment, the code sets the error message ERR-MSG-DATA1 to "Invalid transaction code:" and sets ERR-MSG-DATA2 to the invalid transaction code. The code then calls the 299-REPORT-BAD-TRAN procedure to report the error.
6. Report the transaction processed: The code reports that the transaction was processed by calling the 830-REPORT-TRAN-PROCESSED procedure.
7. Move the transaction key to the previous transaction key: The code moves the transaction key TRAN-KEY to the previous transaction key WS-PREV-TRAN-KEY using the MOVE statement.
8. Check if the transaction was successful: The code checks if the transaction was successful by checking if the transaction status WS-TRAN-OK is set to "Y". If the transaction was successful, the code reports that the transaction was processed.