why is this trim text trailing not working?-CodePudding

       IDENTIFICATION DIVISION.
       PROGRAM-ID. KATA.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01 WS-INPUT      PIC A(200).
       01 WS-OUT        PIC A(200).
       01 I             PIC 9(08).
       01 J             PIC 9(08).
       01 INP-LEN       PIC 9(08).
       PROCEDURE DIVISION.
       DISPLAY "INPUT YOUR STRING"
       ACCEPT WS-INPUT
       DISPLAY "REVERSING ......."
       MOVE FUNCTION LENGTH(FUNCTION TRIM(WS-INPUT TRAILING)) TO INP-LEN
       DISPLAY "Just for reference : Your string is "INP-LEN " long"
       MOVE 1 to I.
       PERFORM VARYING J from INP-LEN by -1 UNTIL J =0
       MOVE WS-INPUT(I:1) to WS-OUT(J:1)
       MOVE FUNCTION TRIM(WS-OUT TRAILING) TO WS-OUT
       ADD 1 to I
       END-PERFORM
       MOVE FUNCTION TRIM(WS-OUT TRAILING) TO WS-OUT.
       DISPLAY WS-OUT
       DISPLAY FUNCTION LENGTH(WS-OUT)
       STOP RUN.

Run the program for input ctrl test

If you run the program you will see that the length of WS-INPUT is :

Just for reference : Your string is 00000009 long

But if you do that for output it will say length of string is 200 Also the reversed string I get is :

tset lrtc

Which is 200 and not what I set.

Can someone explain where I went wrong and what can I do to fix it ?

(Note : I initially tried with function REVERSE so a simple

       MOVE FUNCTION REVERSE(WS-INPUT) TO WS-OUTPUT

same problem was there as well )

CodePudding user response：

FUNCTION LENGTH (source) takes the length from source, in your case that's WS-OUT, which is PIC A(200) - so the answer 200 is correct.

FUNCTION TRIM (source TRAILING) creates as every function a temporary/internal item - in this case removing trailing SPACES from source.

Because of your MOVE of this temporary item with length 9 to one field which is of length 200 it gets right-padded by spaces. Only DYNAMIC LENGTH items get a dynamic size by MOVE, all other items always stay with their size. [keeping "ODO" out for simplicity...]

You possibly want a nested function call: TRIM REVERSE / LENGTH:

DISPLAY FUNCTION LENGTH ( FUNCTION TRIM (WS-OUT) )
DISPLAY "-" FUNCTION REVERSE ( FUNCTION TRIM (WS-IN TRAILING) ) "-"