Portal | Manuals | References | Downloads | Info | Programs | JCLs | Mainframe wiki | Quick Ref
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Profile Log in to check your private messages Log in
 
Sorting a table in Natural

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> Java & MQSeries
View previous topic :: :: View next topic  
Author Message
Ralph Zbrog

New User


Joined: 21 Nov 2009
Posts: 58
Location: California

PostPosted: Thu Apr 15, 2010 1:28 pm    Post subject: Sorting a table in Natural
Reply with quote

In a previous thread, Sid_ibm asked how to sort a set of numbers. Atulbagewadikar provided Natural code for a simple bubble sort, but noted that this was not the most efficient solution. This is quite true. In fact even an optimized double-bubble sort will give you poor performance.

The way to sort an array is via Natural's SORT statement. This technique can be used on-line with fairly large tables.

Typically you have a key and associated data, so here's sample code to sort such an array. The solutions are extracted from my Intermediate Natural training course. The first program is for tables where key and data are defined and initialized separately. The second example is where the key and data are defined as a single entity. In either case the same subprogram is called to perform the sort.

The point to note is that you need a unique sorting subprogram for each combination of key/data format and length.

Program SORTP1 - separate KEY and DATA:
Code:
DEFINE DATA
LOCAL
1 #MAX (I4)             CONST <10>
1 #KEY (A15/#MAX)       INIT <'Smith',   'Jones',   'Able',
                              'Charles', ' ',       'Baker'>
1 #OTHER (A25/#MAX)     INIT <'Jane',    'Andrew',  'Michael',
                              'Alice',   ' ',       'Margaret'>
1 #TOP (I4)             INIT <6>
END-DEFINE
*
DISPLAY
        #MAX
        #TOP
        #KEY (1:#TOP)
        #OTHER (1:#TOP)
CALLNAT "SORTN" #KEY (1:#TOP)     /* (1:#MAX)
                #OTHER (1:#TOP)   /* (1:#MAX)
                #TOP
SKIP 1
DISPLAY
        #MAX
        #TOP
        #KEY (1:#TOP)
        #OTHER (1:#TOP)
END

Program SORTP2 - combined KEY and DATA:
Code:
DEFINE DATA
LOCAL
1 #MAX (I4)             CONST <10>
1 #TBL (A40/#MAX)       INIT <'Smith          ' - 'Jane'
                             ,'Jones          ' - 'Andrew'
                             ,'Able           ' - 'Michael'
                             ,'Charles        ' - 'Alice'
                             ,'               ' - ' '
                             ,'Baker          ' - 'Margaret'
                             >
                        1 REDEFINE #TBL
  2 #ENTRY (#MAX)
    3 #KEY (A15)
    3 #OTHER (A25)
1 #TOP (I4)             INIT <6>
END-DEFINE
*
DISPLAY
        #MAX
        #TOP
        #KEY (1:#TOP)
        #OTHER (1:#TOP)
CALLNAT "SORTN" #KEY (1:#TOP)     /* (1:#MAX)
                #OTHER (1:#TOP)   /* (1:#MAX)
                #TOP
SKIP 1
DISPLAY
        #MAX
        #TOP
        #KEY (1:#TOP)
        #OTHER (1:#TOP)
END

Subprogram SORTN as a bit of extra code to eliminate blank entries:
Code:
DEFINE DATA
PARAMETER
1 #KEY (A15/1:V)
1 #OTH (A25/1:V)
1 #T (I4)
LOCAL
1 #SORT (A15)
1 #OTHER (A25)
1 #I (I4)
1 #M (I4)
END-DEFINE
*
ASSIGN #M = *OCC (#KEY)
FOR #I = 1 #M
  ASSIGN #SORT  = #KEY (#I)
  ASSIGN #OTHER = #OTH (#I)
END-ALL
*
SORT BY #SORT
  USING #OTHER
  AT START OF DATA
    RESET #I
          #KEY (*)
          #OTH (*)
  END-START
  /*
  IF   #SORT  <> ' '
   AND #OTHER <> ' '
    THEN
      ADD 1 TO #I
      ASSIGN #KEY (#I) = #SORT
      ASSIGN #OTH (#I) = #OTHER
  END-IF
END-SORT
ASSIGN #T = #I
END

Both programs display the same results:
Code:
Page     1                                                   04/15/10

   #MAX        #TOP          #KEY                #OTHER
----------- ----------- --------------- -------------------------

         10           6 Smith           Jane
                        Jones           Andrew
                        Able            Michael
                        Charles         Alice

                        Baker           Margaret

         10           5 Able            Michael
                        Baker           Margaret
                        Charles         Alice
                        Jones           Andrew
                        Smith           Jane
Back to top
View user's profile Send private message

View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> Java & MQSeries All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts Extracting DDL for all list of intere... Ashishpanpaliya DB2 5 Mon May 21, 2018 4:08 pm
No new posts Searching a table for the field name? socker_dad COBOL Programming 8 Sat Mar 31, 2018 2:57 am
No new posts Need inputs on DB2 tablespace/table r... ashek15 DB2 3 Sat Mar 24, 2018 11:49 pm
No new posts COBOL declaration for table Poha Eater DB2 3 Mon Feb 26, 2018 6:58 pm
No new posts load and delete table through JCL wit... ram_vizag JCL & VSAM 9 Thu Feb 01, 2018 12:47 am

Facebook
Back to Top
 
Job Vacancies | Forum Rules | Bookmarks | Subscriptions | FAQ | Polls | Contact Us