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IDENTIFICATION DIVISION, ENVIRONMENT DIVISION, DATA DIVISION, PROCEDURE DIVISION.
Alpha-numeric (X), alphabetic (A) and numeric (9).
Alphabetic, Alphanumeric fields & alphanumeric edited items are set to SPACES. Numeric, Numeric edited items set to ZERO. FILLER , OCCURS DEPENDING ON items left untouched.
Elementary level item. Cannot be subdivisions of other items (cannot be qualified), nor can they be subdivided themselves.
For condition names.
For RENAMES clause.
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 - .
01 ARRAYS. 05 ARRAY1 PIC X(9) OCCURS 10 TIMES. 05 ARRAY2 PIC X(6) OCCURS 20 TIMES INDEXED BY WS-INDEX.
No.
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.
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.
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).
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.
Must use compiler option SSRANGE if you want array bounds checking. Default is NOSSRANGE.
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.
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.
See question 16.
See question 16. Restrictions - Cannot massage records, canot select records to be sorted.
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.
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.
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
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.
Yes.
Scope terminator is used to mark the end of a verb e.g. EVALUATE, END-EVALUATE; IF, END-IF.
PERFORM ... ... END 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)
Does nothing ! If used, must be the only sentence within a paragraph.
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.
Yes.
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 installations 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.
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.
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...
In the most significant bit. Bit is on if -ve, off if +ve.
COMP is a binary storage format while COMP-3 is packed decimal format.
COMP-1 - Single precision floating point. Uses 4 bytes. COMP-2 - Double precision floating point. Uses 8 bytes.
No picture clause to be given. Example 01 WS-VAR USAGE COMP-1.
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.
Will occupy 8 bytes (one extra byte for sign).
4 bytes.
99999999
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.
In COBOL II: 16777215
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).
Open for INPUT, OUTPUT, I-O, EXTEND.
OUTPUT, EXTEND
Supply the DD cards just as you would for files referred to in the main program.
Can rewrite(record length must be same), but not delete.
Logic error. e.g., a file is opened for input and an attempt is made to write to it.
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.
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.
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.
DYNAM.
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.
Move a value to RETURN-CODE register. RETURN-CODE should not be declared in your program.
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.
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.
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. |
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MAINFRAME - COBOL INTERVIEW QUESTIONS
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