where we need to use subscripting and where Indexing

richa.setia · New User Joined: 23 Mar 2005 Posts: 10 Location: Noida

Can anybody give the scenarios where we need to use subscripting and where we nede to use Indexing? Also the difference between the two.

Ashutosh Shrinet · New User Joined: 22 Aug 2004 Posts: 10 Location: New Delhi

Hi, Richa
this is the basic differnce between subscript and index,Subscript refers to the array occurrence while index is the displacement (in no of bytes) from the beginning of the array. An index can only be modified using PERFORM, SEARCH & SET. Need to have index for a table in order to use SEARCH, SEARCH ALL.

ashutosh719 · New User Joined: 06 Apr 2005 Posts: 12

Also, index is preferred one...due to enhanced execution speed...
refer stern/stern for more...

thanks.

narasimharao_koganti · New User Joined: 26 Apr 2005 Posts: 11 Location: pune

hi,
index is used for faster access. when the table size is large it is better to go for the index. because index represents the displacement position starting of the array.
the primary difference between index and subscript is, index represents the displacement position, where as subscript represents the occurance position of the element.

vasanthanc · New User Joined: 01 Apr 2005 Posts: 58

thats right. As subscript represents the occurance position, when ever an array element is referred, to retrieve the value, displacement position will be calculated internally and this will take some time as it includes multiplication and in case the array size is large, there will be much time difference. So its better to go for index in case of large arrays

swaran_msc · New User Joined: 19 May 2005 Posts: 5 Location: Bangalore

Yeah... What they said is correct. Also we have no need to declare the index variables in W-S Section whereas declaration is required for Subscript.

Thanks...

Corrections are Welcome

Mohan.r · New User Joined: 07 Mar 2005 Posts: 2

hi,
subscript is advisable to use when u have to point few number of records say 50.
If u have large number of records it is wise one should use index.
In Index concept, data will be pointed internally in binary format that is why it will not take time to point it out. where as it n't the same with subscript, internally it has to convert into binary form and then start pointing to the record and results in time-consuming.

I prefer to use index always.

pa1chandak · New User Joined: 31 Jan 2006 Posts: 55

INDEXING IS BINARY SEARCH

AND SUBSCRIPT IS SERIAL SEARCH

IF I AM WRONG SOMEWHERE PLEASE CORRECT ME

THANK YOU

DO SEND ME THE REPLY

PAWAN

09822546416

// THE ONE I LOVE , I SHALL NEVER BLAME //

kshalini · New User Joined: 20 Feb 2007 Posts: 8 Location: Banglore

Please give elaborate example.
What I can undestand that since Index is defined while delaring an array when we refer a particular array occurence index access is faster because the memory is assigned for an array.
But when referred by subscripts the seach time is more because m/f has to search for teh exact location.
e.g:
01 NAMES.
05 NAME-TBL OCCURS 3 INDEXED BY T.
10 MY-NAME PIC X(10).
SET T TO 1
PERFORM VARYING T FROM 1 BY 1 UNTIL T=3
MOVE 'TONY' TO NAME-TBL(T)
END-PERFORM.
MOVE 2 TO WS-SUB.
DISPLAY 'NAME-TBL(WS-SUB)'NAME-TBL(WS-SUB).
SET T TO 1.
DISPLAY 'NAME-TBL(T)'NAME-TBL(T).

I am getting the same value in both of them
NAME-TBL(WS-SUB)TONY
NAME-TBL(T)TONY

So please elaborate whether the main difference lies in the access time as because when array is defined a fixed memory location is defined by index but for subscript it takes longer time to arraive at the exact location

kshalini · New User Joined: 20 Feb 2007 Posts: 8 Location: Banglore

value will be difnitely same but what i want to know is the exact difference with example

dick scherrer · Posted: Mon Mar 12, 2007 9:53 pm

Hello,

Please search the forum and the Fine Manual.

The topic has been in the forum several times.

From

William Thompson · Posted: Tue Mar 13, 2007 12:59 am