Stateful Goroutines in COBOL

       IDENTIFICATION DIVISION.
       PROGRAM-ID. STATEFUL-ROUTINES.
       ENVIRONMENT DIVISION.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-STATE.
          05 WS-MAP OCCURS 5 TIMES.
             10 WS-KEY PIC 9(5).
             10 WS-VALUE PIC 9(5).
       01 WS-READ-OPS PIC 9(10) COMP.
       01 WS-WRITE-OPS PIC 9(10) COMP.
       01 WS-RANDOM PIC 9(5).

       PROCEDURE DIVISION.
       MAIN-PROCEDURE.
           PERFORM INITIALIZE-STATE
           PERFORM START-ROUTINES
           PERFORM DISPLAY-RESULTS
           STOP RUN.

       INITIALIZE-STATE.
           MOVE 0 TO WS-READ-OPS
           MOVE 0 TO WS-WRITE-OPS.

       START-ROUTINES.
           PERFORM VARYING WS-I FROM 1 BY 1 UNTIL WS-I > 100
               PERFORM READ-ROUTINE
           END-PERFORM
           PERFORM VARYING WS-J FROM 1 BY 1 UNTIL WS-J > 10
               PERFORM WRITE-ROUTINE
           END-PERFORM.

       READ-ROUTINE.
           PERFORM GENERATE-RANDOM
           COMPUTE WS-KEY = FUNCTION MOD (WS-RANDOM, 5) + 1
           ADD 1 TO WS-READ-OPS.

       WRITE-ROUTINE.
           PERFORM GENERATE-RANDOM
           COMPUTE WS-KEY = FUNCTION MOD (WS-RANDOM, 5) + 1
           PERFORM GENERATE-RANDOM
           MOVE WS-RANDOM TO WS-VALUE (WS-KEY)
           ADD 1 TO WS-WRITE-OPS.

       GENERATE-RANDOM.
           COMPUTE WS-RANDOM = FUNCTION RANDOM * 100000.

       DISPLAY-RESULTS.
           DISPLAY "readOps: " WS-READ-OPS
           DISPLAY "writeOps: " WS-WRITE-OPS.

In this COBOL example, we’ve translated the concept of stateful goroutines to a more procedural approach, which is more suitable for COBOL’s paradigm. Here’s an explanation of the key parts:

1. We define a state structure WS-STATE with a map-like array WS-MAP that can hold 5 key-value pairs.

2. We use WS-READ-OPS and WS-WRITE-OPS to keep track of the number of read and write operations.

3. The MAIN-PROCEDURE initializes the state, starts the routines, and displays the results.

4. START-ROUTINES simulates the concurrent operations by performing 100 read operations and 10 write operations.

5. READ-ROUTINE and WRITE-ROUTINE simulate the read and write operations on the state. They use a random number generator to select keys and values.

6. GENERATE-RANDOM creates a random number, simulating the functionality of rand.Intn() in the original Go code.

7. Finally, DISPLAY-RESULTS shows the number of read and write operations performed.

This COBOL program doesn’t have true concurrency like the Go version with goroutines. Instead, it sequentially performs the read and write operations. The concept of channels for communication between goroutines is replaced by direct updates to the shared state and operation counters.

To run this COBOL program, you would typically compile it and then execute the resulting binary. The exact commands may vary depending on your COBOL compiler and environment.

$ cobc -x stateful-routines.cob
$ ./stateful-routines
readOps: 0000000100
writeOps: 0000000010

Note that the actual numbers of read and write operations will be fixed in this COBOL version, unlike the Go version where they could vary due to the concurrent nature of goroutines.