user7910505
user7910505

Reputation:

COBOL program won't end

I am currently writing a COBOL program with a screen that checks and display a record from a file. However, the program keeps getting stuck when I try to input a command other than "F" or "Q". While it is suppose to display a new screen with an error message.The error message that I am trying to invoke is "<>"

Identification Division.
   Program-ID.      Lab10b.

   Environment Division.
   Input-Output Section.
   File-Control.
       Select InFile Assign to "Lab10b-master.dat"
       Organization is Indexed
       Access Mode is Random
       Record Key is Movie-Key
       Status is FileStatus.

   Data Division.
   File Section.
   FD  InFile.
   01  Movie.
       05  Movie-Key       Pic 9(5).
       05  Movie-Title     Pic X(50).
       05  Movie-Genre     Pic X(20).

   Working-Storage Section.
   01  black   constant as 0.
   01  blue    constant as 1.
   01  green   constant as 2.
   01  cyan    constant as 3.
   01  red     constant as 4.
   01  magenta constant as 5.
   01  brown   constant as 6.
   01  white   constant as 7.
   01  Today-Date.
       05 YYYY                Pic 9(4).
       05 MM                  Pic 9(2).
       05 DD                  Pic 9(2).
   01  FileStatus             Pic 99.
   01  Error-Message          Pic X(50).
   01  Res1.
       05 a                   Pic X.
       05 b                   Pic X.
       05 c                   Pic X.
       05 d                   Pic X.
       05 e                   Pic X.
   01  Res2                   Pic X.
       88 Quit       Value "Q" "q".
       88 Find       Value "F" "f".

   Screen Section.
   01  data-screen.
       05 screen-header.
          10 PH-Month Blank Screen Line 01 Col 01 Pic Z9/ From MM.
          10 PH-Day Line 01 Col 04 Pic 99/ From DD.
          10 PH-Year Line 01 Col 07 Pic 9999 From YYYY.
          10 Value "Stomper & Wombat's Movie Warehouse"
             Line 01 Col 40.
       05 screen-data.
          10 Value "Movie #:      " Line 05 Col 9.
          10 Movie-Number-Out Line 05 Col 24
             Pic 9(5) from Movie-Key Blank When Zero.
          10 Value "Title:         " Line 06 Col 9.
          10 Movie-Title-Out Line 06 Col 24
             Pic X(50) From Movie-Title.
          10 Value "Genre:         " Line 07 Col 9.
          10 Movie-Genre-Out Line 07 Col 24
             Pic X(50) From Movie-Genre.
       05 Error-Message-Out Line 11 Col 15 Pic X(50)
          From Error-Message foreground-color red.
       05 screen-response.
          10 Value "Key:           [" Line 13 Col 9.
          10 Key-Response Line 13 Col 25 Pic X(5) to Res1.
          10 Value "]" Line 13 Col 30.
       05 screen-response2.
          10 Value "Command:       [" Line 14 Col 9.
          10 Command-response Line 14 Col 25 Pic X to Res2.
          10 Value "]" Line 14 Col 26.


   Procedure Division.
   000-Main.
       Accept Today-Date From Date YYYYMMDD
       Move YYYY To PH-Year
       Move MM To PH-Month
       Move DD To PH-Day

       Open Input InFile
       Move " " to Error-Message
       Display data-screen
       Accept screen-response2
       If Res2 = "F" Or "f"
          Accept screen-response
       End-If

       Perform Until res2 = "q" or "Q"
          Move " " to Error-Message
          If res2 <> "Q" And "q" and "f" and "F" *> If Command Response is not valid, Write this error message.
             Move "<<Command Invalid>>" to Error-Message
          Else if res2 = "f" Or "F" *> If command = find
             If a = " " And b = " " And c = " " And d = " "
             And e = " " *> Check if key is empty
                Move "<<Key Must Be Provided>>" to Error-Message
                Move " " to Movie
             Else If (a = " " Or b = " " Or c = " " Or d = " "
             Or e = " ") Or res1 is not numeric *> Check if key is numeric and complete?
                Move "<<Invalid Key>>" to Error-Message
                Move " " to Movie
             Else
                Move res1 to Movie-Key
                Read InFile
                Evaluate FileStatus
                   When 00
                      Continue
                   When 23
                      Move " " to Movie
                      Move "<<Key Not Found>>" to Error-Message
                   When Other
                      Move "<<Unknown Read Error>>" to Error-Message
                End-Evaluate
             End-If
          Else
             Continue
          End-If

          Display data-screen
          Accept screen-response2
          If Res2 = "F" Or "f"
             Accept screen-response
          End-If
       End-Perform

       Close InFile
       Stop Run.

Upvotes: 0

Views: 634

Answers (1)

Roger Sinasohn
Roger Sinasohn

Reputation: 483

Perhaps this might be easier to read and debug:

01   Perform Until res2 = "q" or "Q"
02      Move " " to Error-Message
03      If res2 <> "Q" And "q" and "f" and "F" 
04         Move "<<Command Invalid>>"                 to Error-Message
05      Else
06         if res2 = "f" Or "F" 
07            If a = " " And b = " " And c = " " And d = " " And
08               e = " " *> Check if key is empty
09               Move "<<Key Must Be Provided>>"      to Error-Message
10               Move " "                             to Movie
11            Else
12               If (a = " " Or b = " " Or c = " " Or d = " "
13                   Or e = " ") Or res1 is not numeric
14                  Move "<<Invalid Key>>"            to Error-Message
15                  Move " "                          to Movie
16               Else
17                  Move res1                         to Movie-Key
18                  Read InFile
19                  Evaluate FileStatus
20                    When 00
21                      Continue
22                    When 23
23                      Move " "                      to Movie
24                      Move "<<Key Not Found>>"      to Error-Message
25                    When Other
26                      Move "<<Unknown Read Error>>" to Error-Message
27                  End-Evaluate
28               End-If
29         Else
30            Continue
31         End-If
32
33      Display data-screen
34      Accept screen-response2
35      If Res2 = "F" Or "f"
36         Accept screen-response
37      End-If
38   End-Perform

(I added line numbers for easy reference.)

Here's what's happening: You're missing an end-if in there somewhere.

You're likely missing one after line 28, but that's not the problem. Because you already had an else (on line 11) for the if on line 7, the else will terminate the if from line 7 and apply to the one on line 6.

I believe you're missing another end-if after line 31. What's happening currently is that if you enter something other than Q and F, it does the move on line 4, and then skips everything between the else on line 5 and when the if is terminated. Because you're missing the end-if after line 31, it skips everything up until the end-perform on line 38.

A little clarification: The reason it goes into an endless loop if you enter something other than Q or F is that it's skipping the accept on line 34 and thus you have no opportunity to enter anything else. And because your perform continues until res2 = "q" or "Q", which it clearly isn't, it will just keep looping forever.

This is why proper indentation is so very necessary. Once I indented everything, it was obvious what the problem was. It might be okay for you to just type stuff every which way, but if someone else has to come along later and work on this you'll make them hate you very quickly. If it's neat and clear, they'll love you.

Also, I notice you have 88 levels defined for Quit and Find but you don't use them. They would make your code a lot more readable. And the tests with a = " " etc on lines 7 & 8 could be simplified by using if res1 = spaces (assuming OpenCOBOL works the way it should; I've not used it.)

Hope this helps.

Upvotes: 1

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