Name the divisions in a COBOL program.
IDENTIFICATION DIVISION, ENVIRONMENT DIVISION,
DATA DIVISION, PROCEDURE DIVISION.
What are the different data types available in
COBOL?
Alpha-numeric (X), alphabetic (A) and numeric
(9).
What does the INITIALIZE verb do? �
Alphabetic, Alphanumeric fields &
alphanumeric edited items are set to SPACES.
Numeric, Numeric edited items set to ZERO.
FILLER , OCCURS DEPENDING ON items left
untouched.
What is 77 level used for ?
Elementary level item. Cannot be subdivisions
of other items (cannot be qualified), nor can they be subdivided
themselves.
What is 88 level used for ?
For condition names.
What is level 66 used for ?
For RENAMES clause.
What does the IS NUMERIC clause establish ?
IS NUMERIC can be used on alphanumeric items,
signed numeric & packed decimal items and usigned numeric & packed
decimal items. IS NUMERIC returns TRUE if the item only consists of 0-9.
However, if the item being tested is a signed item, then it may contain 0-9, +
and - .
How do you define a table/array in COBOL?
01 ARRAYS.
05 ARRAY1 PIC X(9) OCCURS 10 TIMES.
05 ARRAY2 PIC X(6) OCCURS 20 TIMES INDEXED BY
WS-INDEX.
Can the OCCURS clause be at the 01 level?
No.
What is the difference between index and
subscript?
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.
What is the difference between SEARCH and
SEARCH ALL?
SEARCH - is a serial search.
SEARCH ALL - is a binary search & the table
must be sorted ( ASCENDING/DESCENDING KEY clause to be used & data loaded in this
order) before using SEARCH ALL.
What should be the sorting order for SEARCH
ALL?
It can be either ASCENDING or DESCENDING.
ASCENDING is default. If you want the search to be done on an array sorted in
descending order, then while defining the array, you should give DESCENDING KEY
clause. (You must load the table in the specified order).
What is binary search?
Search on a sorted array. Compare the item to
be searched with the item at the center. If it matches, fine else repeat the
process with the left half or the right half depending on where the item
lies.
My program has an array defined to have 10
items. Due to a bug, I find that even if the program access the 11th item in
this array, the program does not abend. What is wrong with it?
Must use compiler option SSRANGE if you want
array bounds checking. Default is NOSSRANGE.
How do you sort in a COBOL program? Give sort
file definition, sort statement syntax and meaning.
Syntax:
SORT file-1 ON ASCENDING/DESCENDING KEY
key....
USING file-2
GIVING file-3.
USING can be substituted by INPUT PROCEDURE IS
para-1 THRU para-2
GIVING can be substituted by OUTPUT PROCEDURE
IS para-1 THRU para-2.
file-1 is the sort workfile and must be
described using SD entry in FILE SECTION.
file-2 is the input file for the SORT and must
be described using an FD entry in FILE SECTION and SELECT clause in FILE
CONTROL.
file-3 is the outfile from the SORT and must be
described using an FD entry in FILE SECTION and SELECT clause in FILE
CONTROL.
file-1, file-2 & file-3 should not be
opened explicitly.
INPUT PROCEDURE is executed before the sort and
records must be RELEASEd to the sort work file from the input procedure.
OUTPUT PROCEDURE is executed after all records
have been sorted. Records from the sort work file must be RETURNed one at a time
to the output procedure.
How do you define a sort file in JCL that runs
the COBOL program?
Use the SORTWK01, SORTWK02,..... dd names in
the step. Number of sort datasets depends on the volume of data being sorted,
but a minimum of 3 is required.
What are the two ways of doing sorting in a
COBOL program? Give the formats.
See question 16.
Give the format of USING and GIVING in SORT
statement. What are the restrictions with it?
See question 16. Restrictions - Cannot massage
records, canot select records to be sorted.
What is the difference between performing a
SECTION and a PARAGRAPH?
Performing a SECTION will cause all the
paragraphs that are part of the section, to be performed.
Performing a PARAGRAPH will cause only that
paragraph to be performed.
What is the use of EVALUATE statement?
Evaluate is like a case statement and can be
used to replace nested Ifs. The difference between EVALUATE and case is that no
'break' is required for EVALUATE i.e. control comes out of the EVALUATE as soon
as one match is made.
What are the different forms of EVALUATE
statement?
EVALUATE EVALUATE SQLCODE ALSO FILE-STATUS
WHEN A=B AND C=D WHEN 100 ALSO '00'
imperative stmt imperative stmt
WHEN (D+X)/Y = 4 WHEN -305 ALSO '32'
imperative stmt imperative stmt
WHEN OTHER WHEN OTHER
imperative stmt imperative stmt
END-EVALUATE END-EVALUATE
EVALUATE SQLCODE ALSO A=B EVALUATE SQLCODE ALSO
TRUE
WHEN 100 ALSO TRUE WHEN 100 ALSO A=B
imperative stmt imperative stmt
WHEN -305 ALSO FALSE WHEN -305 ALSO (A/C=4)
imperative stmt imperative stmt
END-EVALUATE END-EVALUATE
How do you come out of an EVALUATE statement?
After the execution of one of the when clauses,
the control is automatically passed on to the next sentence after the EVALUATE
statement. There is no need of any extra code.
In an EVALUATE statement, can I give a complex
condition on a when clause?
Yes.
What is a scope terminator? Give examples.
Scope terminator is used to mark the end of a
verb e.g. EVALUATE, END-EVALUATE; IF, END-IF.
How do you do in-line PERFORM?
PERFORM ... ...
END PERFORM
When would you use in-line
perform?
When the body of the perform will not be used
in other paragraphs. If the body of the perform is a generic type of code (used
from various other places in the program), it would be better to put the code in
a separate para and use PERFORM paraname rather than in-line
perform.
27. What is the difference between CONTINUE
& NEXT SENTENCE ?
CONTINUE is like a null statement (do nothing)
, while NEXT SENTENCE transfers control to the next sentence (!!) (A sentence is
terminated by a period)
What does EXIT do ?
Does nothing ! If used, must be the only
sentence within a paragraph.
Can I redefine an X(100) field with a field of
X(200)?
Yes. Redefines just causes both fields to start
at the same location. For example:
01 WS-TOP PIC X(1)
01 WS-TOP-RED REDEFINES WS-TOP PIC X(2).
If you MOVE '12' to WS-TOP-RED,
DISPLAY WS-TOP will show 1 while
DISPLAY WS-TOP-RED will show 12.
Can I redefine an X(200) field with a field of
X(100) ?
Yes.
What do you do to resolve SOC-7 error?
Basically you need to correcting the offending
data.
Many times the reason for SOC7 is an
un-initialized numeric item. Examine that possibility first.
Many installation provide you a dump for run time
abends ( it can be generated also by calling some subroutines or OS services
thru assembly language). These dumps provide the offset of the last instruction
at which the abend occurred. Examine the compilation output XREF listing to get
the verb and the line number of the source code at this offset. Then you can
look at the source code to find the bug. To get capture the runtime
dumps, you will have to define some datasets (SYSABOUT etc ) in the JCL.
If none of these are helpful, use judgement and
DISPLAY to localize the source of error.
Some installtion might have batch program debugging tools. Use them.
How is sign stored in Packed Decimal fields
and Zoned Decimal fields?
Packed Decimal fields: Sign is stored as a hex
value in the last nibble (4 bits ) of the storage.
Zoned Decimal fields: As a default, sign is
over punched with the numeric value stored in the last bite.
How is sign stored in a comp-3 field?
It is stored in the last nibble. For example if
your number is +100, it stores hex 0C in the last byte, hex 1C if your number is
101, hex 2C if your number is 102, hex 1D if the number is -101, hex 2D if the
number is -102 etc...
How is sign stored in a COMP field ?
In the most significant bit. Bit is on if -ve,
off if +ve.
What is the difference between COMP &
COMP-3 ?
COMP is a binary storage format while COMP-3 is
packed decimal format.
What is COMP-1? COMP-2?
COMP-1 - Single precision floating point. Uses
4 bytes.
COMP-2 - Double precision floating point. Uses
8 bytes.
How do you define a variable of COMP-1?
COMP-2?
No picture clause to be given. Example 01
WS-VAR USAGE COMP-1.
How many bytes does a S9(7) COMP-3 field
occupy ?
Will take 4 bytes. Sign is stored as hex value
in the last nibble.
General formula is INT((n/2) + 1)), where n=7
in this example.
How many bytes does a S9(7) SIGN TRAILING
SEPARATE field occupy ?
Will occupy 8 bytes (one extra byte for
sign).
How many bytes will a S9(8) COMP field occupy
?
4 bytes.
What is the maximum value that can be stored
in S9(8) COMP?
99999999
What is COMP SYNC?
Causes the item to be aligned on natural
boundaries. Can be SYNCHRONIZED LEFT or RIGHT.
For binary data items, the address resolution
is faster if they are located at word boundaries in the memory. For example, on
main frame the memory word size is 4 bytes. This means that each word will start
from an address divisible by 4. If my first variable is x(3) and next
one is s9(4) comp, then if you do not specify
the SYNC clause, S9(4) COMP will start from byte 3 ( assuming that it starts
from 0 ). If you specify SYNC, then the binary data item will start from address
4. You might see some wastage of memory, but the access to this
computational field is faster.
What is the maximum size of a 01 level item in
COBOL I? in COBOL II?
In COBOL II: 16777215
How do you reference the following file
formats from COBOL programs:
Fixed Block File - Use ORGANISATION IS
SEQUENTIAL. Use RECORDING MODE IS F, BLOCK CONTAINS 0 .
Fixed Unblocked - Use ORGANISATION IS
SEQUENTIAL. Use RECORDING MODE IS F, do not use BLOCK CONTAINS
Variable Block File - Use ORGANISATION IS
SEQUENTIAL. Use RECORDING MODE IS V, BLOCK CONTAINS 0. Do not code the 4 bytes
for record length in FD ie JCL rec length will be max rec length in pgm + 4
Variable Unblocked - Use ORGANISATION IS
SEQUENTIAL. Use RECORDING MODE IS V, do not use BLOCK CONTAINS. Do not code 4
bytes for record length in FD ie JCL rec length will be max rec length in pgm +
4.
ESDS VSAM file - Use ORGANISATION IS
SEQUENTIAL.
KSDS VSAM file - Use ORGANISATION IS INDEXED,
RECORD KEY IS, ALTERNATE RECORD KEY IS
RRDS File - Use ORGANISATION IS RELATIVE,
RELATIVE KEY IS
Printer File - Use ORGANISATION IS SEQUENTIAL.
Use RECORDING MODE IS F, BLOCK CONTAINS 0. (Use RECFM=FBA in JCL DCB).
What are different file OPEN modes available
in COBOL?
Open for INPUT, OUTPUT, I-O, EXTEND.
What is the mode in which you will OPEN a file
for writing?
OUTPUT, EXTEND
In the JCL, how do you define the files
referred to in a subroutine ?
Supply the DD cards just as you would for files
referred to in the main program.
can you REWRITE a record in an ESDS file? Can
you DELETE a record from it?
Can rewrite(record length must be same), but
not delete.
What is file status 92?
Logic error. e.g., a file is opened for input
and an attempt is made to write to it.
What is file status 39 ?
Mismatch in LRECL or BLOCKSIZE or RECFM between
your COBOL pgm & the JCL (or the dataset label). You will get file status 39
on an OPEN.
What is Static,Dynamic linking ?
In static linking, the called subroutine is
link-edited into the calling program , while in dynamic linking, the subroutine
& the main program will exist as separate load modules. You choose
static/dynamic linking by choosing either the DYNAM or NODYNAM link edit option.
(Even if you choose NODYNAM, a CALL identifier (as opposed to a CALL literal),
will translate to a DYNAMIC call).
A statically called subroutine will not be in
its initial state the next time it is called unless you explicitly use INITIAL
or you do a CANCEL. A dynamically called routine will always be in its initial
state.
What is AMODE(24), AMODE(31), RMODE(24) and
RMODE(ANY)? ( applicable to only
MVS/ESA Enterprise Server)
These are compile/link edit options.
AMODE - Addressing mode. RMODE - Residency
mode.
AMODE(24) - 24 bit addressing. AMODE(31) - 31
bit addressing. AMODE(ANY) - Either 24 bit or 31 bit addressing depending on
RMODE.
RMODE(24) - Resides in virtual storage below 16 Meg line. Use this for 31 bit
programs that call 24 bit programs. (OS/VS Cobol pgms use 24 bit addresses
only).
RMODE(ANY) - Can reside above or below 16 Meg
line.
What compiler option would you use for dynamic
linking?
DYNAM.
What is SSRANGE, NOSSRANGE ?
These are compiler options w.r.t subscript out
of range checking. NOSSRANGE is the default and if chosen, no run time error
will be flagged if your index or subscript goes out of the permissible
range.
How do you set a return code to the JCL from a
COBOL program?
Move a value to RETURN-CODE register.
RETURN-CODE should not be declared in your program.
How can you submit a job from COBOL programs?
Write JCL cards to a dataset with
//xxxxxxx SYSOUT=(A,INTRDR) where 'A' is output
class, and dataset should be opened for output in the program. Define a 80 byte
record layout for the file.
What are the differences between OS VS COBOL
and VS COBOL II?
OS/VS Cobol pgms can only run in 24 bit
addressing mode, VS Cobol II pgms can run either in 24 bit or 31 bit addressing
modes.
Report writer is supported only in OS/VS
Cobol.
USAGE IS POINTER is supported only in VS COBOL
II.
Reference modification eg: WS-VAR(1:2) is
supported only in VS COBOL II.
EVALUATE is supported only in VS COBOL II.
Scope terminators are supported only in VS
COBOL II.
OS/VS Cobol follows ANSI 74 stds while VS COBOL
II follows ANSI 85 stds.
Under CICS Calls between VS COBOL II programs
are supported.
What are the steps you go through while
creating a COBOL program executable?
DB2 precompiler (if embedded sql used), CICS
translator (if CICS pgm), Cobol compiler, Link editor.
If DB2 program, create plan by binding the
DBRMs.
Can you call an OS VS COBOL pgm from a VS
COBOL II pgm ?
In non-CICS environment, it is possible. In
CICS, this is not possible