How to replace spaces at the right into zeros at the left in COBOL?
Solution 1
You should test your code with an input of all blanks.
If you are absolutely certain of the quality of the data, and with or without the check for blanks, you can do this:
ID DIVISION.
PROGRAM-ID. VARSWAP.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 VARIN PIC X(10).
88 NO-VARIN-PRESENT VALUE SPACE.
01 VARSWAP PIC 9(10).
PROCEDURE DIVISION.
MOVE '123456 ' TO VARIN
IF NO-VARIN-PRESENT
do what your spec says
ELSE
UNSTRING VARIN DELIMITED BY ' ' INTO VARSWAP
END-IF
DISPLAY VARSWAP
GOBACK
.
I don't like destroying the input, so I changed that.
A popular way to do it is, FUNCTION REVERSE ( your-field ), followed by INSPECT reversed-field TALLYING ... FOR LEADING SPACES. You can use FUNCTION LENGTH early in your program to determine the length of the fields (and ensure they are the same length) and then, setting your VARIN to ZERO first, use reference-modification for the source and the target - source will be ( 1 : calculated-length-of-data ) target will be ( calculated-start-for-right-justification : ) (not specifying the length uses the remaining part of the field).
There are also variable-length fields, byte-by-byte MOVEs (sometimes preferred by "traditionalists", but the least clear of the lot).
Exactly how you do it depends on your data. If you need to validate the data, you need code for that first, and that will make the choice more clear to you. If your data is, guaranteed, clean, then...
I know it is only an example, but I hope you use nicer data-names for real.
Solution 2
Bill Woodger mentioned: "There are also ... byte-by-byte MOVEs (sometimes preferred by "traditionalists", but the least clear of the lot)." Here is one such solution that I hope is reasonably clear. Below are two version. First, a solution updated for the suggestions below. Second, the original solution proposed, to reference in understanding the comments made. Thank you, Bill, for your good suggestions! I might learn to write good COBOL one of these days :)
IDENTIFICATION DIVISION.
PROGRAM-ID. SHIFT-RIGHT.
* SITUATION ON STACKOVERFLOW.COM:
* I HAVE AN ALPHANUMERIC VARIABLE WITH A LENGTH OF 10.
* IT CONTAINS A NUMBER AT THE BEGINNING, THE REST OF THE DIGITS
* ARE FILLED WITH SPACES. THEN I NEED TO MOVE THE STRING TO THE
* LEFT AND PUT THE NUMBER OF SPACES WITH '0' AT THE BEGINING.
* THIS EXAMPLES SPEAKS FOR THEMSELVES:
* INPUT OUTPUT
* ==============================
* '123456 ' -> '0000123456'
* '12345678 ' -> '0012345678'
* '123456789 ' -> '0123456789'
* '1234567890' -> '1234567890'
*
* ASSUME INPUT DATA VALIDATION DONE ELSEWHERE.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
DATA DIVISION.
FILE SECTION.
WORKING-STORAGE SECTION.
01 STRING-IN PIC X(10).
01 STRING-OUT PIC X(10).
01 STRING-LENGTH PIC 99 USAGE COMP.
01 CHAR-IN-NUM PIC 99 USAGE COMP.
01 CHAR-OUT-NUM PIC 99 USAGE COMP.
PROCEDURE DIVISION.
MAIN.
PERFORM INITIALIZE-LENGTH
MOVE '123456 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '12345678 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '123456789 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '1234567890' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE SPACES TO STRING-IN
PERFORM MAKE-AND-SHOW
STOP RUN
.
INITIALIZE-LENGTH.
MOVE LENGTH OF STRING-IN TO STRING-LENGTH
IF LENGTH OF STRING-OUT NOT = STRING-LENGTH
DISPLAY 'LENGTH OF STRING-IN, ' STRING-LENGTH ', '
'NOT EQUAL TO LENGTH OF STRING-OUT, '
LENGTH OF STRING-OUT
STOP RUN
END-IF
.
MAKE-AND-SHOW.
PERFORM MAKE-STRING-OUT
PERFORM SHOW-BEFORE-AFTER
.
MAKE-STRING-OUT.
MOVE ZEROS TO STRING-OUT
MOVE STRING-LENGTH TO CHAR-OUT-NUM
CHAR-IN-NUM
PERFORM STRING-LENGTH TIMES
IF STRING-IN (CHAR-IN-NUM:1) NOT = SPACE
MOVE STRING-IN (CHAR-IN-NUM:1)
TO STRING-OUT (CHAR-OUT-NUM:1)
SUBTRACT 1 FROM CHAR-OUT-NUM
END-IF
SUBTRACT 1 FROM CHAR-IN-NUM
END-PERFORM
.
SHOW-BEFORE-AFTER.
DISPLAY "STRING IN: '" STRING-IN "'"
DISPLAY "STRING OUT: '" STRING-OUT "'"
DISPLAY " "
.
**********************************************
* EARLIER VERSION, BEFORE IMPROVEMENTS
* SUGGESTED IN COMMENTS
**********************************************
IDENTIFICATION DIVISION.
PROGRAM-ID. SHIFT-LEFT.
* SITUATION ON STACKOVERFLOW.COM:
* I HAVE AN ALPHANUMERIC VARIABLE WITH A LENGTH OF 10.
* IT CONTAINS A NUMBER AT THE BEGINNING, THE REST OF THE DIGITS
* ARE FILLED WITH SPACES. THEN I NEED TO MOVE THE STRING TO THE
* LEFT AND PUT THE NUMBER OF SPACES WITH '0' AT THE BEGINING.
* THIS EXAMPLES SPEAKS FOR THEMSELVES:
* INPUT OUTPUT
* ==============================
* '123456 ' -> '0000123456'
* '12345678 ' -> '0012345678'
* '123456789 ' -> '0123456789'
* '1234567890' -> '1234567890'
*
* ASSUME INPUT DATA VALIDATION DONE ELSEWHERE.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
DATA DIVISION.
FILE SECTION.
WORKING-STORAGE SECTION.
01 STRING-IN PIC X(10).
01 STRING-OUT PIC X(10).
01 CHAR-IN-NUM PIC 99 USAGE COMP-3.
01 CHAR-OUT-NUM PIC 99 USAGE COMP-3.
PROCEDURE DIVISION.
MAIN.
MOVE '123456 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '12345678 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '12345678 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '123456789 ' TO STRING-IN
PERFORM MAKE-AND-SHOW
MOVE '1234567890' TO STRING-IN
PERFORM MAKE-AND-SHOW
STOP RUN
.
MAKE-AND-SHOW.
PERFORM MAKE-STRING-OUT
PERFORM SHOW-BEFORE-AFTER
.
MAKE-STRING-OUT.
MOVE SPACES TO STRING-OUT
MOVE 10 TO CHAR-OUT-NUM
PERFORM VARYING CHAR-IN-NUM FROM 10 BY -1
UNTIL CHAR-IN-NUM < 1
IF STRING-IN (CHAR-IN-NUM:1) NOT = SPACE
MOVE STRING-IN (CHAR-IN-NUM:1)
TO STRING-OUT (CHAR-OUT-NUM:1)
SUBTRACT 1 FROM CHAR-OUT-NUM
END-IF
END-PERFORM
PERFORM UNTIL CHAR-OUT-NUM < 1
MOVE ZERO TO STRING-OUT (CHAR-OUT-NUM:1)
SUBTRACT 1 FROM CHAR-OUT-NUM
END-PERFORM
.
SHOW-BEFORE-AFTER.
DISPLAY "STRING IN: '" STRING-IN "'"
DISPLAY "STRING OUT: '" STRING-OUT "'"
DISPLAY " "
.
Solution 3
If you have intrinsics, shuffle a FUNCTION TRIM, with LEADING or TRAILING as fits purpose, through a pic 9. TRAILING in this case, or both in the example below.
identification division.
program-id. rjust.
data division.
working-storage section.
01 str pic x(10) value '123 '.
01 some-n pic 9(10).
procedure division.
move function trim(str) to some-n
move some-n to str
display some-n, " : ", str end-display
goback.
0000000123 : 0000000123
As Bill mentioned above with validation, this assumes all spaces is the equivalent of 0. That may or may not be a sane thing to allow. Non digits being an issue as well.
Solution 4
The easiest way is to use the WITH CONVERSION clause on the move statement, and if you aren't sure of the input, add the ON EXCEPTION clause.
IDENTIFICATION DIVISION.
PROGRAM-ID. ONCONVERSION.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 VARIN PIC X(10).
01 VAROUT PIC 9(10).
PROCEDURE DIVISION.
MOVE '123456 ' TO VARIN
MOVE VARIN TO VAROUT WITH CONVERSION
ON EXCEPTION
MOVE ZERO TO VAROUT
END-MOVE
DISPLAY VARIN
STOP RUN.
Solution 5
I am surprised no one has suggested using NUMVAL here...
IDENTIFICATION DIVISION.
PROGRAM-ID. EXAMPLE.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 VARIN PIC X(10).
01 VAROUT PIC 9(10).
PROCEDURE DIVISION.
MOVE '123456 ' TO VARIN
COMPUTE VAROUT = FUNCTION NUMVAL(VARIN)
DISPLAY '>' VARIN '<'
DISPLAY '>' VAROUT '<'
GOBACK
.
which produces...
>123456 <
>0000123456<
The problem with this approach is that if the NUMVAL
argument does not convert to
numeric the program throws an exception and dies. Also this is not very
efficient from a CPU usage point of view because it requires character to
binary numeric conversion and back to display format again (all done under the covers but takes cycles).
As a general rule I would not recommend using NUMVAL (even if it looks like a 'nicer' solution). I would stick with the solution as presented in the original question. That solution is computationally efficient and is a common idiom used in COOBL programming.
mllamazares
Updated on June 05, 2022Comments
-
mllamazares almost 2 years
I have an alphanumeric variable with a length of 10. It contains a number at the beginning, the rest of the digits are filled with spaces. Then I need to move the string to the left and put the number of spaces with '0' at the begining. This examples speaks for themselves:
INPUT OUTPUT ============================== '123456 ' -> '0000123456' '12345678 ' -> '0012345678' '123456789 ' -> '0123456789' '1234567890' -> '1234567890'
Then I tought in something like this:
Check this COBOL fiddle where you can try: http://ideone.com/mgbKZ3 (just click on edit)
IDENTIFICATION DIVISION. PROGRAM-ID. VARSWAP. ENVIRONMENT DIVISION. DATA DIVISION. WORKING-STORAGE SECTION. 01 VARIN PIC X(10). 01 VARSWAP PIC X(10) JUSTIFIED RIGHT. PROCEDURE DIVISION. MOVE '123456 ' TO VARIN UNSTRING VARIN DELIMITED BY ' ' INTO VARSWAP INSPECT VARSWAP REPLACING LEADING SPACE BY '0' MOVE VARSWAP TO VARIN DISPLAY VARIN STOP RUN.
Returns:
0000123456
It seems work ok, but I wonder if you have a better, simpler, or clearer way to do it.
-
Bill Woodger about 10 yearsNot all implementations of intrinsic functions have TRIM, perhaps only the more extensive implementations :-)
-
Bill Woodger about 10 years
WITH CONVERSION
is not standard COBOL, nor isEND-MOVE
. After theON EXCEPTION
, what is your source field? Is is it zero, space or invalid? Can't tell, can you? You may want to edit yourDISPLAY
copied from the original, and indicate which COBOL you are using. "Easy" is relative... -
mllamazares about 10 yearsYeah, in my case I don't have TRIM function.
-
Bill Woodger about 10 yearsEven with editing characters in the field, NUMVAL/NUMVALC has that kicker - fails with bad data, as you point out. On the Mainframe it is not converted to binary (or not alone), results are return as floating-point values, even worse amounts of conversion code... can't bring myself to use it :-) For a simple, always valid, string of numeric data, UNSTRING for sure. Yes, 99/100 who know about
JUST RIGHT
willINSPECT
. Doesn't mean they won't understand when a naturally right-justified field is used instead, which also does the zero-fill by default. Others will NUMVAL without a qualm... -
Bill Woodger about 10 years@Candil you can get GNU COBOL from SourceForge. And then use TRIM. Even just for practice and fun out-of-hours.
-
Bill Woodger about 10 yearsWe'll get the Perl people all excited shortly :-) Nicely laid out. I'd
MOVE ZERO TO STRING-OUT
, make the firstPERFORM
TIMES
and kill the second PERFORM. I'd make the COMP-3s into COMP. Traditionalists, traditionally, wouldn't have used reference-modification... -
Valdis Grinbergs about 10 yearsThanks, Bill, that is even better. Here is the paragraph rewritten: MAKE-STRING-OUT. MOVE ZEROS TO STRING-OUT MOVE 10 TO CHAR-OUT-NUM CHAR-IN-NUM PERFORM 10 TIMES IF STRING-IN (CHAR-IN-NUM:1) NOT = SPACE MOVE STRING-IN (CHAR-IN-NUM:1) TO STRING-OUT (CHAR-OUT-NUM:1) SUBTRACT 1 FROM CHAR-OUT-NUM END-IF SUBTRACT 1 FROM CHAR-IN-NUM END-PERFORM .
-
Bill Woodger about 10 yearsAnother suggestion. If you want to avoid the literal 10s, you can use
LENGTH OF
(if available to you) orFUNCTION LENGTH ( STRING-IN )
. You can use the same method to get the length of the output field, and check they are equal. Stick them in a field, and use the field for setting values and theTIMES
. Do all of that up at the top of the program. A little protection against unknowing program-changes, and minimise those pesky literal which should all be the same, until the same maintainer hits it and gets all but one... Edit whatever you are happy with into your answer. -
Bill Woodger about 10 yearsThere is no need to have the old version explicitly in your answer. Comments on SO are ephemeral. Once you finish your update, we can delete them. The original code still exists in the edit revision history anyway. Comments can always be flagged, obsolete, two chatty, not consturctive. Questions/Answers can be flagged to request removal of comments which are no longer useful as well.
-
Scott Nelson about 10 yearsI guess I've been using AcuCobol too long that I didn't realize that
WITH CONVERSION
is non-standard. My intent is that, if the conversion fails, I would move zero to the output. Another option would be to have more elaborate diagnostics in that case, perhaps evenSTOP "BAD DATA"
.