Issues with GO TO statement on execution past the first time - cobol

Question

Having issues with using the GO-TO statement. This is suppose to run until the user types 'END'. If I type 'END' when I first open the program it will close out but if I type it after entering valid data for the first pass thru it just continues to bring back the user input data screen.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
SELECT USED-CAR-FILE-OUT
ASSIGN TO 'USED-CAR.RPT'
ORGANIZATION IS LINE SEQUENTIAL.
DATA DIVISION.
FILE SECTION.
FD USED-CAR-FILE-OUT.
01 USED-CAR-RECORD-OUT PIC X(80).
WORKING-STORAGE SECTION.
01 FIRST-RECORD PIC X(3) VALUE 'YES'.
01 ID-CODE PIC X(3).
01 TOTAL-CASH-PAYMENT PIC 9(5).
01 MONTHLY-PAYMENT PIC 9(4).
01 NUMBER-OF-MONTHS PIC 9(3).
01 TOTAL-BALANCE PIC S9(6)V99 VALUE ZEROS.
01 INTEREST-COLLECTED PIC 99V99 VALUE ZEROS.
01 MONTH-DIFF PIC 99 VALUE ZEROS.
01 MONTH-NUM PIC 99 VALUE ZEROS.
01 YEAR-NUM PIC 99 VALUE ZEROS.
01 ID-HOLD PIC X(3) VALUE SPACES.
01 PAYMENT-HOLD PIC X(3) VALUE SPACES.
01 DETAIL-LINE.
05 ID-CODE-DL PIC X(3).
05 PIC X(3) VALUE SPACES.
05 PIC X(4) VALUE 'Yr='.
05 YEAR-NUMBER-DL PIC Z9.
05 PIC X(4) VALUE SPACES.
05 PIC X(4) VALUE 'MO='.
05 MONTH-NUMBER-DL PIC Z9.
05 PIC X(4) VALUE SPACES.
05 PIC X(5) VALUE 'Pmt='.
05 PAYMENT-DL PIC $$$,$$$.
05 PIC X(4) VALUE SPACES.
05 PIC X(5) VALUE 'Int='.
05 INTEREST-EARNED-DL PIC $$$$.99.
05 PIC X(3) VALUE SPACES.
05 PIC X(5) VALUE 'Bal='.
05 BALANCE-DL PIC $$$,$$$.99.
PROCEDURE DIVISION.
100-MAIN.
OPEN OUTPUT USED-CAR-FILE-OUT
PERFORM 200-USER-INPUT THRU 299-EXIT
CLOSE USED-CAR-FILE-OUT
STOP RUN.
200-USER-INPUT.
DISPLAY 'Used Car Sales Report'
DISPLAY 'Enter the ID code (or END) - maxium three char.'
ACCEPT ID-CODE
IF ID-CODE = 'END'
GO TO 299-EXIT
END-IF
DISPLAY 'Enter the Total Cash Payment - maximum five digits'
ACCEPT TOTAL-CASH-PAYMENT
DISPLAY 'Enter the Monthly Payment - maximum four digits'
ACCEPT MONTHLY-PAYMENT
DISPLAY 'Enter the Number of Months - maximum three digits'
ACCEPT NUMBER-OF-MONTHS
PERFORM 300-RECORD-PROCESS.
299-EXIT.
EXIT.
300-RECORD-PROCESS.
IF TOTAL-CASH-PAYMENT > 0
IF FIRST-RECORD = 'YES'
MOVE ID-CODE TO ID-CODE-DL
MOVE 1 TO YEAR-NUMBER-DL
MOVE 1 TO YEAR-NUM
move 1 to MONTH-NUMBER-DL
MOVE TOTAL-CASH-PAYMENT TO PAYMENT-DL
MOVE PAYMENT-DL TO MONTHLY-PAYMENT
ADD MONTHLY-PAYMENT TO TOTAL-BALANCE
MOVE 'NO' TO FIRST-RECORD
END-IF
COMPUTE INTEREST-COLLECTED ROUNDED = TOTAL-BALANCE
* .0175 / 12
MOVE INTEREST-COLLECTED TO INTEREST-EARNED-DL
ADD INTEREST-COLLECTED TO TOTAL-BALANCE
MOVE TOTAL-BALANCE TO BALANCE-DL
ADD 1 TO MONTH-DIFF
MOVE MONTH-DIFF TO MONTH-NUMBER-DL
IF MONTH-NUMBER-DL > 13
ADD 1 TO MONTH-NUM
MOVE MONTH-NUM TO MONTH-NUMBER-DL
END-IF
IF MONTH-NUMBER-DL = 13
MOVE 1 TO MONTH-NUM
MOVE MONTH-NUM TO MONTH-NUMBER-DL
END-IF
IF MONTH-NUM = 1
ADD 1 TO YEAR-NUM
MOVE YEAR-NUM TO YEAR-NUMBER-DL
END-IF
MOVE DETAIL-LINE TO USED-CAR-RECORD-OUT
WRITE USED-CAR-RECORD-OUT
AFTER ADVANCING 1 LINE
MOVE ID-HOLD TO ID-CODE-DL
IF MONTH-DIFF < NUMBER-OF-MONTHS
PERFORM 300-RECORD-PROCESS
END-IF
PERORM 200-USER-INPUT
END-IF
IF MONTHLY-PAYMENT > 0
IF FIRST-RECORD = 'YES'
MOVE ID-CODE TO ID-CODE-DL
MOVE 1 TO YEAR-NUMBER-DL
MOVE 1 TO YEAR-NUM
move 1 to MONTH-NUMBER-DL
MOVE 'NO' TO FIRST-RECORD
END-IF
MOVE MONTHLY-PAYMENT TO PAYMENT-DL
MOVE PAYMENT-DL TO MONTHLY-PAYMENT
ADD MONTHLY-PAYMENT TO TOTAL-BALANCE
COMPUTE INTEREST-COLLECTED ROUNDED = TOTAL-BALANCE
* .0175 / 12
MOVE INTEREST-COLLECTED TO INTEREST-EARNED-DL
ADD INTEREST-COLLECTED TO TOTAL-BALANCE
MOVE TOTAL-BALANCE TO BALANCE-DL
ADD 1 TO MONTH-DIFF
MOVE MONTH-DIFF TO MONTH-NUMBER-DL
IF MONTH-NUMBER-DL > 13
ADD 1 TO MONTH-NUM
MOVE MONTH-NUM TO MONTH-NUMBER-DL
END-IF
IF MONTH-NUMBER-DL = 13
MOVE 1 TO MONTH-NUM
MOVE MONTH-NUM TO MONTH-NUMBER-DL
END-IF
IF MONTH-NUM = 1
ADD 1 TO YEAR-NUM
MOVE YEAR-NUM TO YEAR-NUMBER-DL
END-IF
MOVE DETAIL-LINE TO USED-CAR-RECORD-OUT
WRITE USED-CAR-RECORD-OUT
AFTER ADVANCING 1 LINE
MOVE ID-HOLD TO ID-CODE-DL
IF TOTAL-CASH-PAYMENT > 0
MOVE 0 TO TOTAL-CASH-PaYMENT
MOVE 0 TO PAYMENT-DL
END-IF
IF MONTH-DIFF < NUMBER-OF-MONTHS
PERFORM 300-RECORD-PROCESS
END-IF
PERFORM 200-USER-INPUT
END-IF.
EDIT solved the issue below
I also am having issues if months > 24. I step through the program and it shows my last detail line as the correct result but yet my output stops at 24 months. Thanks in advance.

Answer 1

AAAAAAAk!
PERFORM SEVERE-BEATING-ON-WHOEVER-MENTIONED-PERFORM-THROUGH
USING HEAVY-OBJECT
UNTIL PROMISE-EXTRACTED-TO-NEVER-DO-IT-AGAIN.
PERFORM THOUGH is EVIL. It causes layout-dependent code.
At the top control-level, use
PERFORM 200-USER-INPUT
UNTIL ID-CODE = 'END'.
(or possibly use 88 USER-INPUT-ENDED on ID-CODE - matter of style)
How you then determine whether to continue with input in 200-... is your choice, either
IF NOT USER-INPUT-ENDED
DISPLAY 'Enter the Total Cash Payment - maximum five digits'
ACCEPT TOTAL-CASH-PAYMENT
...
ACCEPT NUMBER-OF-MONTHS
PERFORM 300-RECORD-PROCESS.
OR
IF NOT USER-INPUT-ENDED
PERFORM 210-ACCEPT-DETAILS.
210-ACCEPT-DETAILS.
DISPLAY 'Enter the Total Cash Payment - maximum five digits'.
ACCEPT TOTAL-CASH-PAYMENT.
...
ACCEPT NUMBER-OF-MONTHS.
PERFORM 300-RECORD-PROCESS.
Since you PERFORMED 200-... then only 200-... will be executed; 210-... is a new paragraph which can only be reached from 200-... IF END is not entered.
Next step is to slightly modify 300-...
Move the initialisation ( FIRST-RECORD = 'YES' code) before the PERFORM 300-... in 200-... and then modify the PERFORM 300-RECORD-PROCESS. to
PERFORM 300-RECORD-PROCESS
UNTIL TOTAL-BALANCE = 0.
(I'm assuming here that this is the report-terination condition; if it isn't, substitute your report-termination condition)
You can now restructure 300-... to calculate the interest payable, modify the year and month numbers and show the result. ALL of the PERFORMs in 300-... will disappear.
So, in essence you have
MAIN:perform user-input until end-detected.
user-input: get user data; perform calculations until balance is zero.
calculations: one month's calculations at a time.
This also has the advantage that if you choose, you could insert
IF MONTHLY-PAYMENT IS LESS THAN INTEREST-COLLECTED
MOVE 'ERR' TO ID-CODE.
And use 'ERR' in ID-CODE to produce an appropriate error-message in 300-... instead of the progressive report lines AND at the same time assign 0 to TOTAL-BALANCE which terminates the PERFORM 300-... UNTIL ....

Answer 2

Your use of GO TO and PERFORM THROUGH paragraph ranges has corrupted the procedure return mechanism that COBOL
uses to maintain proper program flow of control. In essence, you have a program that is invalid - it might compile
without error but is still an invalid program according to the rules of COBOL.
Here is an outline of what your program is doing from a flow of control perspective. The
mainline program is essentially:
100-MAIN.
PERFORM 200-USER-INPUT THRU 299-EXIT
This is asking COBOL to execute all the code found from the beginning of
200-USER-INPUT through to the end of 299-EXIT. The outline for these
procedures is:
200-USER-INPUT.
IF some condition GO TO 299-EXIT
...
PERFORM 300-RECORD-PROCESS
.
299-EXIT.
Notice that if some condition is true, program flow will skip past the end
of 200-USER-INPUT and jump into 299-EXIT. 299-EXIT does not do anything
very interesting, it is just an empty paragraph serving as the end of a
PERFORMed range of paragraphs.
In paragraph 300-RECORD-PROCESS you have a fair bit of code. The interesting
bit is:
300-RECORD-PROCESS.
...
PERFORM 200-USER-INPUT
Notice that PERFORM 200-USER-INPUT this is not a PERFORM THRU, as you had coded in 100-MAIN.
The problem is that when you get back into 200-USER-INPUT and some codition becomes
true (as it will when you enter 'EXIT'), the flow of control
jumps to 299-EXIT which is past the end of the paragraph
you are currently performing. From this point
forward the flow of control mechanism used by COBOL to manage return from PERFORM verbs has
been corrupted. There is no longer a normal flow of control mechanism to return back to where 200-USER-INPUT
was performed from in 300-RECORD-PROCESS.
What happens next is not what most programmers would expect. Most programmers seem to expect
that when the end of 299-EXIT is reached program flow should return to wherever the last PERFORM
was done. In this case, just after PERFORM 200-USER-INPUT. No, COBOL doesn't work that way, flow of control
will continue with the next executable statement following 299-EXIT. This gets you
right back to the first executable statement in 300-RECORD-PROCESS! And that is why you
are not getting expected behaviour from this program.
Logic flow in COBOL programs must ensure that the end of performed procedures are
always reached in the reverse order from which they were made. This corresponds to the call/return
stack semantics that
most programmers are familiar with.
My advice to you is to avoid the use of PERFORM THRU and GO TO. These are two of the biggest
evils left in the COBOL programming language today. These constructs are hang-overs from a
bygone era of programming and have no constructive benefit today.

Answer 3

Your problem is that you have created an infinite loop for yourself. You 200- paragraph PERFORMs the 300- paragraph, and your 300- paragraph PERFORMS your 200- paragraph.
You need to restructure your program.
A paragraph called 200-USER-INPUT should just concern itself with that.
repeat until end of input
get some input
if there is input to process
process the input
Yoiks! I just noticed you also PERFORM 300- from within 300-!