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About memory allocation of tables

 
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Lavanya_Dhushetty
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PostPosted: Fri Sep 14, 2007 10:06 am    Post subject: About memory allocation of tables
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See the following table definition:

01 WS-TABLE.
05 WS-VAR-A PIC X(2) OCCURS 1 to 90 TIMES DEPENDING ON WS-D.

If WS-D is 50 how much memory will be used by this table?

Answers:
a.180 Bytes
b.90 Bytes
c.COBOL will allocate depending on the availability of the memory
d.100 Bytes
e.182 Bytes
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agkshirsagar

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PostPosted: Fri Sep 14, 2007 11:15 am    Post subject:
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Answer a.
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agkshirsagar

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PostPosted: Fri Sep 14, 2007 11:19 am    Post subject:
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COBOL will allocate maximum memory that can an OCCURS DEPENDING ON table can occupy. I hope you are clear with the answer now.. icon_smile.gif

This can be confusing but it is the fact. Dynamic memory allocation is not very easy in COBOL.
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Lavanya_Dhushetty
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PostPosted: Fri Sep 14, 2007 11:40 am    Post subject: Reply to: About memory allocation of tables
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How it could be A???????Can U please explain it???
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murmohk1

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PostPosted: Fri Sep 14, 2007 11:54 am    Post subject:
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Abhijit,

Go thru the following link -

http://publib.boulder.ibm.com/infocenter/iadthelp/v7r0/index.jsp?topic=/com.ibm.etools.iseries.langref.doc/c0925395765.htm

Sample quote from the link -

Quote:
The length of TABLE-1 is calculated by multiplying the contents of COUNTER-1 (the number of occurrences of RECORD-1) by 3 (the length of RECORD-1).
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agkshirsagar

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PostPosted: Fri Sep 14, 2007 12:35 pm    Post subject:
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Lavanya, I have already given the explanation. This much explantion should be enough for an interview question. I told you this can be confusing, as your experience will grow then things will be clearer to you.

One more thing, I was actually expecting question like 'What is advantage of occurs depending on if it allocates max memory?'
Here is the key-
You don't save memory in program, but when you write record to file, you will save those bytes. Let me know if you have any further question.

Murali,
Question was about memory allocation I guess. Not about calculating length of field. COBOL does not dynamically allocate memory for occurs depending on.
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Anuj Dhawan

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PostPosted: Fri Sep 14, 2007 1:45 pm    Post subject: Re: Reply to: About memory allocation of tables
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Lavanya_Dhushetty wrote:
How it could be A???????Can U please explain it???

What should be the answer accroding to you ?
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dick scherrer

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PostPosted: Fri Sep 14, 2007 8:54 pm    Post subject:
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Hello,

Quote:
How it could be A???????Can U please explain it???


Quote:
PIC X(2) OCCURS 1 to 90 TIMES

How could the length be anything other than 180 (2x90)?
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Craq Giegerich

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PostPosted: Fri Sep 14, 2007 9:22 pm    Post subject:
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dick scherrer wrote:
Hello,

Quote:
How it could be A???????Can U please explain it???


Quote:
PIC X(2) OCCURS 1 to 90 TIMES

How could the length be anything other than 180 (2x90)?


The amount of memory allocated for the table would be 180 but the amount used would be 100 (2 x 90 and 2 x 50). The extra 80 bytes would be wasted since it can not be reallocated.
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dick scherrer

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PostPosted: Fri Sep 14, 2007 9:43 pm    Post subject:
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Hello,

I believe that (unlike dasd) when space is allocated by a load module it is also used. Those bytes are filled (just not referenced when the code runs).

I suppose the "right" answer to the original question depends on how the question was intended icon_smile.gif
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