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CDC_Covansys_ChennaiCOBOL _ # 1 _Ver 2.0

COBOL

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Chapter - 1 - Introduction

1.1 History Of COBOL

1950s Growing need for a high-level languagesuitable for programming in business dataprocessing

1958 US Department of Defence convened a

conference to form three groups to startwith the actual design of the language

1959 1st report on COBOL (COmmon BusinessOriented Language)

1960 Modified version of the earlier report ;CODASYL(Conference on DATA System Language) COBOLprogramming language - the board of directorateestablished a COBOL maintenance committee tokeep COBOL in step with the times

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1.1 History Of COBOL

1961 COBOL-61 published with some revisionsof the 1960 report; the basis for later versions

1962 1st COBOL compiler made available ; usersstarted writing programs in COBOL

1965 Next Version

1968 Standard Version of COBOL approved bythe American National Standards Institute(ANSI)

1974 ANSI 74 COBOL (COBOL 74)

1985 ANSI 85 COBOL (COBOL II / COBOL 85)

1990s COBOL 9x (Proposed)


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1.2 Features Of COBOL

Oriented towards business applications

English-like

Self-Documenting

Machine independent

Easy to Learn / Read / Write / Test

I/O operations easily designated

Structured Programming Support


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1.3 Source Coding Rules

1 6 7 8 11 12 72 73 80

Sequence

Number Area A Area B

Area

Indicator Area Ignored Area


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Indicator Area

* in column 7 Line treated as a comment ; Shown in thesource listing

/ in column 7 Line treated as a comment ; Source listingbegins a new page before printing the line

- in column 7 Line treated as continuation of previous line ;(hyphen )

Except when non-numeric literals are continued, all trailingspaces on the preceding line and all leading spaces on thecontinuation line, are ignored ;


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Area A

Area A (columns 8 thru 11) of the continuation line must be blank

Cols 1 thru 6 Each line of code may have a 6 digit line number

Line numbers to be in ascending order

Blanks also permitted

Area A Reserved for DIVISION, SECTION & PARAGRAPHheaders

File description entry indicators (FD & SD), level nos. 01 and 77

Comment line characters also accepted, provided column 7contains an * or /


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Area B

Area B Reserved for Filenames associated with FD or SDindicators and the SELECT clause

Level nos. 02 to 49 and 66 and 88

Descriptive clauses and/or data descriptions that make up specific

paragraph entries

Continuation lines, provided column7 contains a (hyphen) -


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1.4 COBOL Character Set and Words

COBOL Character Set

51 different characters

0 to 9 10 Numerals - digits

A to Z 26 English alphabets - letters

Space or Blank ( generally denoted as b )

Note_01 The Space or Blank character in certain cases is treated asa letter


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COBOL Character Set

51 different characters

- + * / = Minus/Hyphen

Plus

Asterisk

Slash

Equal to

$ ( ) < > Currency

Left parenthesisRight parenthesis

Less than

Greater than


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COBOL Character Set

51 different characters . , ; " Period/Decimal point

Comma

Semi Colon

Quotes

Collating Sequence

An ordering that defines the relative rank of all the validcharacters in a computer system


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1.4.2 COBOL Words

User-Defined Words

Formed from 0 to 9, A to Z and hyphen (-)

Not to be more than 30 characters long

( greater than 30 characters in case of COBOL 9x )

Not to contain blank or any special character except hyphen (-)

Not to begin with or end with a hyphen (-) ; Can have hyphens inbetween

Should contain at least one alphabet

Should not be a reserved word


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1.4.2 COBOL Words

User-Defined Words

Practice

BASIC-PAY-BASIC-A

OVERTIME-H0URS OVER TIME RATE

1-2-3

B12-4

AGE-IN-YEARS

COVANSYS INDIA PRIVATE LIMITED


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Reserved Words

Have a specific meaning to the compiler

Must be spelt correctly and used in the proper context

Cannot be used as user-defined words in a program

Eg.

PERFORM, IDENTIFICATION, MOVE, IF, DIVISION


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Data Names & Identifiers

Refer to the storage space in memory where the actual value isstored

The value takes part in the operation when that particular dataname is used in the Procedure Division

In certain cases a data name alone is not good enough for use inthe Procedure Division. In such cases, the data name has to bequalified by another data name or can be indexed or subscripted

In general, a single data name or a data name qualified, indexedor subscripted is normally referred to by the term identifier

To be a user-defined word and not a reserved word


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Data Names & Identifiers

Exercise

TOTAL-HOURS

DATA

ADD

QTY-REQUIRED

46-2A

A45

46+2A

46 - 2A

342B2

45


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Literals

Actual values that appear in the program, instead of a data name

The value of a data name can vary during program execution, but,

that of a literal, is specific and remains unchanged throughout theprogram execution

Represent themselves and are not required to be defined in the

Data Division


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Literals


Numeric Literal Non-Numeric Literal

Can have digits alone Used to output messages/headings

A combination of either of + -and/or a period (.)

Characters enclosed within quotes ( )

+ - to be the leftmost character ;

No blank between the sign and the first digit ;

Period (.) not to be the lastcharacter ;

If no period (.), treated as integer ;If no sign, treated as positive

Any character within quotes except another quote

() ;

In ANSI 74, whenever a quote( or ) is to be represented as a part of a value,

it is to replicated( or respectively )

eg DONT WORRY

DONT WORRY

Max # of digits 18(compiler dependent)

Max # of characters 120(compiler dependent)(greater than 120 characters in case of COBOL 9x)

C

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Literals

Practice

.725

150

12.5

SEVEN

12.5

-46

-38.62


Practice

EIGHT-24.

2345678923456789234.5689

QTY*PRICE12.5

DATA DIVISION

7

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Figurative Constants

Literals representing values that may be frequently used by mostprograms

Fixed names that are recognized by the compiler which sets up thecorresponding values in the object program

Eg1. ZERO 0

ZEROS

ZEROES

SPACE b

SPACES

ALL ******

Eg2.

MOVE 0 TO TOTAL

can be written as MOVE ZERO TO TOTAL


QUOTE

QUOTES

HIGH-VALUE maximum possiblealpha-numeric value ;

HIGH-VALUES the computer's highest value

LOW-VALUE minimum possiblealpha-numeric value ;

LOW-VALUES the computer's lowest value

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1.5 COBOL Program StructureIDENTIFICATION DIVISION.

PROGRAM-ID. entry.

[AUTHOR. author name.][INSTALLATION. installation name.]

[DATE-WRITTEN. written-date.]

[DATE-COMPILED. compiled-date.]

[SECURITY. authorization.]

[REMARKS. prologue.]

ENVIRONMENT DIVISION.[CONFIGURATION SECTION.

SOURCE-COMPUTER. source-computer-entry.

OBJECT-COMPUTER. object-computer-entry.

[SPECIAL-NAMES. special-names-entry.] ]

INPUT-OUTPUT SECTION.

FILE-CONTROL. {file-control-entry}...

DATA DIVISION.FILE SECTION.WORKING-STORAGE SECTION.

[Working-Storage section entries.

PROCEDURE DIVISION.

[ [section name SECTION.]

[ [paragraph name. [statements/sentences]...]...]...]


C CO O

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Chapter - 2 COBOL Divisions

2.1 Identification Division

First division of a COBOL program - the leading division

Specifies information about the program to others who mayread or use the program

Contains several paragraphs

The PROGRAM-ID paragraph is mandatory ; Otherparagraphs are optional and are used mainly for

documentation purposes

Division headings and Paragraph names to be coded asmargin A entries

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2.1 Identification Division

Paragraph names to end with a period followed by at least oneblank space

Entries following paragraph names to be terminated with aperiod

PROGRAM-ID paragraph entry - program name with at least

one letter within the 30 allowable characters

Optional paragraph entries - treated as comments

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Sample Program

IDENTIFICATION DIVISION.

PROGRAM-ID. EXAMPLE-01.

AUTHOR. CVNS(I).

DATE-WRITTEN. 01-01-1999.

DATE-COMPILED. 01-01-1999.

SECURITY. RESTRICTED TO THE TRAINING DEPT.

INSTALLATION. CVNS(I).


Ch 2 COBOL Di i i

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2.2 Environment Division

Second division of a COBOL program

Most machine-dependent division of all the four

Specifies the computer and all other peripheral devicesrequired by the program

Division headings, Section headings and Paragraph headings

to be followed by a period and a space

Paragraph entries coded as margin B entries allowed to startin the same line with the paragraph heading

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2.2.1 Configuration Section

Overall specification of the computer used for the purpose ofcompilation & execution of the program

SOURCE-COMPUTER. (para-1)

Name of the computer used to compile the COBOL program

Eg. SOURCE-COMPUTER. computer-name.

Ch 2 COBOL Di i i

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Configuration Section

OBJECT-COMPUTER. (para-2)

Name of the computer used to execute the COBOL program

Eg. OBJECT-COMPUTER. computer-name.

SPECIAL-NAMES. (para-3)

Relate some hardware names to user-specified mnemonic names

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Eg.

SPECIAL-NAMES. [,CURRENCY SIGN IS literal-1]

[,DECIMAL-POINT IS COMMA]

Currency When a currency symbol other than $ is

required ; A one-character symbol ( not a digit ;not one of A to D,L,P,R,S,V,X,Z ; not special

characters blank * - , . ; () + / = )

Decimal-Point To edit a numeric data in the European manner

and thus interchange the roles of comma (,)

and period (.) as edit characters

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Eg.

ENVIRONMENT DIVISION.

CONFIGURATION SECTION.

SOURCE-COMPUTER. CVNS(I)-PC-nn.

OBJECT-COMPUTER. CVNS(I)-PC-nn.

SPECIAL-NAMES. CURRENCY IS &.

Ch t 2 COBOL Di i i

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2.2.2 Input-Output Section

Information regarding files to be used in the program

File-Control (para-1)

Name of each file and the file medium associated with it

Eg.FILE-CONTROL.SELECT [OPTIONAL] file-name ASSIGN TO hardware name

One file control entry each for all the files used in a COBOLsource program

An entry to name the file and assign a peripheral device whichholds that particular file

Ch t 2 COBOL Di i i

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File-name in SELECT clause to be unique and to be

mandatorily described in the data division. Optional

Used only for input files

Optional files need not be present on every occasion

when the object program is executed

Any attempt to open an optional file, that is absent,

will not result in an error ; the absent optional file

will be considered to be an empty file (that does not

contain any record)

If the OPTIONAL clause is omitted and the file is not present forreading while executing the program, an execution error will occur

Ch t 2 COBOL Di i i

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If the OPTIONAL clause is omitted and the file is not present forreading while executing the program, an execution error willoccur

Assign

Assign a particular physical peripheral device name to a file

Physical peripheral device names are machine dependent

Chapter 2 COBOL Divisions

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Input-Output Section

Eg.DISK, PRINTER, READER, TAPE ....

Eg.






FILE-CONTROL.

SELECT CVNS(I)-File-001ASSIGN TO DISK.

SELECT CVNS(I)-File-002 ASSIGN TO PRINTER.

Ch t 2 COBOL Di i i

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2.3 Data Division

Part of a COBOL program where every data item processedby the program is described

Unless a data item is specified in the Data Division, it cannotbe used in the Procedure Division

Divided into a number of sections ; a data item is defined in anappropriate section depending on its usage


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2.3 Data Division

File Section

Description of all data items that should be read from or written onto, some external file

FD ( File Description ) entry for each file in the program followed bythe record description

Record description begins with a record name

( Always at 01 level )


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Data Division

Eg. The relationships among

SELECT, FD, 01 and FIELDS

SELECT names the file and ASSIGN

assigns it to a hardware deviceFD describes the file

01 names the record format

02-49 describes the fields

within the record format


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Working-Storage Section

Descriptions of all data items whose values are developedinternally as intermediate results, as well as, the constants

Succeeds the File Section

It is a common practice to group related items together


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Working-Storage Section

Eg.

DATA DIVISION.

...........

WORKING-STORAGE SECTION.01 WS-ALL-VARS.

05 WS-SUM1 PIC 999.

05 WS-SUM2 PIC 999.

05 WS-TOTAL PIC 9(4).


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Linkage Section

Appears in a called program

Describes records or non-contiguous data items with respect to

which connections should be established with the calling program

Corresponding data items in the calling program may be defined

in any section of the Data Division


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Linkage Section

Eg.

DATA DIVISION.

...........

...........LINKAGE SECTION.

01 LS-ALL-VARS.

05 LS-RECD1 PIC 999.

05 LS-RECD2 PIC 999.

05 LS-RECD3 PIC 9(4).


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2.4 Procedure Division

Contains statements which specify the operations to beperformed by the computer

Each of these statements is formed with COBOL words andliterals

A statement always starts with a COBOL verb


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Eg.

PROCEDURE DIVISION.

0001-MAIN-PARA.

DISPLAY ENTER FIRST NUMBER AT 0510.

ACCEPT WS-SUM1.

DISPLAY ENTER SECOND NUMBER AT 0710.ACCEPT WS-SUM2.

COMPUTE WS-TOTAL = WS-SUM1 + WS-SUM2.

DISPLAY THE SUM IS WS-TOTAL.

STOP RUN.

0001-MAIN-EXIT-PARA.

EXIT.


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2.5 Sample Program - 01


PROGRAM-ID. EXAMPLE-01.

AUTHOR. CVNS(I).

DATE-WRITTEN. 01-01-1999.DATE-COMPILED. 01-01-1999.






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DATA DIVISION.

WORKING-STORAGE SECTION.

01 WS-ALL-VARS.

05 WS-SUM1 PIC 999.

05 WS-SUM2 PIC 999.

05 WS-TOTAL PIC 9(4).

PROCEDURE DIVISION.

0001-MAIN-PARA.DISPLAY ENTER FIRST NUMBER AT 0510.

ACCEPT WS-SUM1.

DISPLAY ENTER SECOND NUMBER AT 0710.

ACCEPT WS-SUM2.

COMPUTE WS-TOTAL = WS-SUM1 + WS-SUM2.DISPLAY THE SUM IS , WS-TOTAL.

STOP RUN.


EXIT.


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2.6 Sample Program - 02

IDENTIFICATION DIVISION.PROGRAM-ID. EXAMPLE-02.

AUTHOR. CVNS(I).

DATE-WRITTEN. 01-01-1999.

DATE-COMPILED. 01-01-1999.




OBJECT-COMPUTER. CVNS(I)-PC-nn.INPUT-OUTPUT SECTION.

FILE-CONTROL.

SELECT STOK-FILE ASSIGN TO DISK.


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DATA DIVISION.

FILE SECTION.

FD STOK-FILE

LABEL RECORDS ARE STANDARD

VALUE OF FILE-ID IS STOK.DAT.

01 STOK-ITEM.

02 STOCK-CODE PIC X(4).

02 PROD-DESC PIC X(24).

02 UNIT-SIZE PIC 9(4).


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PROCEDURE DIVISION.

0001-FST-PARA.

DISPLAY ERASE.OPEN INPUT STOK-FILE.

DISPLAY FILE OPENED .

0001-FST-EXIT-PARA.

EXIT.0001-SEC-PARA.

CLOSE STOK-FILE.

DISPLAY END OF PROGRAM.

STOP RUN.0001-SEC-EXIT-PARA.

EXIT.

Chapter - 3 - Picture Clause

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Introduction

Specified for every elementary data item

Eg.

Data Item Type Symbols for Character String

Numeric 9 S V ( )

Alphabetic A ( )

Alphanumeric 9 X A ( )


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Syntax

{ PICTURE } IS character-string

{ PIC }

Code Character Meaning

9 Data item contains a numeral

X Data item contains any allowable

character from the COBOL character set

A Data item contains only a letter or space

V Data item contains an assumed decimal point

S Data item is signed

( specified as the left most character )


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Chapter 3 Picture Clause

Note_01

Code Character Nature of the Stored Value

A, X is Left.......... Justified

9 is ..........Right Justified

S is either Positive or Negative


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Internal Representation

Picture Data Representation

AAAA ABCD ABCD

A(04) XYZ XYZb

XXXX ?e/X ?e/X

X(05) 123 123bb

9(03) 123 123


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Picture Data Representation

9(04) 123 0123

99V99 38.50 38 50

9(4)V9(2) 34.5 0034 50

99V9 123.45 23 4

S9(4)V99 123.45 0123 45

S9(3)V99 -12.3 012 30


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3.3 Editing Symbols

Need for editing data

Edit Types Numeric data

Z Zero Suppression

* Asterisk

$ Currency sign

- Minus sign

+ Plus sign

CR DB Credit Debit Sign


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Edit Types Numeric data

. Period

, Comma

B Z / Blank, Zero, Slash Insertion

BLANK WHEN ZERO b

$ + - Floating Insertion

Edit Types Alphabetic

Blank Insertion

Edit Types Alphanumeric

Blank, Zero, Slash Insertion


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Chapter 3 Picture Clause Mutually Exclusive Symbols

V . + - + - CR DB S $ + - Z *

3.4 Zero Suppression Z

Its a zero suppression character that replaces each non-significant zero with a blank space

In the process, the commas that are embedded within the non-significant zeroes are also suppressed (replaced with blank

spaces)

To be used only with numerals


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Eg.

Pic of the Field Numeric Value Edited Value

ZZ999 04678 b4678

ZZ999 00052 bb052

ZZ999 1.68 bb001

ZZZV99 38 4 b3840

ZZZV99 0 65 bbb65

ZZZZVZZ 0 05 bbbb05

ZZZZVZZ 0 bbbbbb


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3.5 Asterisk *

Acts as a check protection symbol

Its a zero suppression character that replaces each non-significant zero with an asterisk (*)

In the process, the commas that are embedded within the non-significant zeroes are also replaced with asterisks (*)


Eg. Pic of the Field Numeric Value Edited Value

**999 04678 *4678 **999 00052 **052

**999 1.68 **001


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3.6 Currency Sign $

Its a zero suppression character that replaces each non-significant zero with a dollar ($)

In the process, the commas that are embedded within the non-significant zeroes are also replaced with dollars ($)



$99999 985 $00985

$99999 32264 $32264

$ZZ999 985 $bb985

$ZZ999 32264 $32264

$**999 985 $**985


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C apte 3 ctu e C ause

3.7 Minus Sign -

A minus sign can appear either at the leftmost or therightmost position of a picture

If the value of a data item is negative, a minus sign willappear in the said position

If the value of the data item is positive, a space character willappear instead

Eg Pic of the Field Numeric Value Edited Value

-9999 -382 -0382

-9999 382 b0382

9999- -382 0382-

9999- 382 0382b

-ZZZV99 -46 2 -b4652

-ZZZV99 46 52 bb4652


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p

3.8 Plus Sign +

A plus sign, like the minus sign, can appear either at theleftmost or the rightmost position of a picture

If the value of a data item is positive, a plus sign will appear inthe said position

If the value of the data item is negative, a minus sign will appearinstead

Eg. Pic of the Field Numeric Value Edited Value +9999 -382 -0382

+9999 382 +0382

9999+ -382 0382- 9999+ 382 0382+

+ZZZV99 -46 52 -b4652

+ZZZV99 46 52 +b4652


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p

3.9 Credit Debit Sign CR DB

The two symbols CR and DB can appear only at the rightmost position of the picture

They are identical to the minus sign edit character

The symbol CR or DB will appear at the right most position ifthe item is negative, otherwise it will be replaced by two spacecharacters

Eg. Pic of the Field Numeric Value Edited Value 9999CR -4625 4625CR

9999CR 4625 4625bb ZZZCR -42 b42CR

ZZ9V99DB -152 25 15225DB

ZZZ9V99DB 52 25 bb5225bb


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p

3.10 Period . A period may be used to insert a decimal point and may not appear

more than once A period must not appear as the rightmost character position in thepicture

If Zero Suppression is also specified, the period stops zerosuppression on its right

All the digits before and after the period happen to be zeros, the

period does not stop zero suppression and the entire field includingthe period is space-filled

Eg. Pic of the Field Numeric Value Edited Value 999.99 324.52 324.52

ZZ99.99 45.25 bb45.25

ZZ99.99 245 b245.00 ZZZZ.ZZ 0.05 bbbb.05

ZZZZ.ZZ 0 bbbbbbb

****.** 0 ****.**

$ZZZ9.99 0285 $b285.00


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p

3.11 Comma Insertion ,

Dollar signs & Commas are editing symbols frequently used inconjunction with suppression of leading zeroes and printing ofdecimal points

Eg. Pic of the Field Numeric Value Edited Value 99,999 2456 02,456

99,999 37 00,037

ZZ,Z99 2456 b2,456

**,*** 12 ****12

*,***,** 246 ****2,46

*,***,** 123456 1,234,56

ZZ,Z9.99 123.45 b1,23.45


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p

3.12 Blank Insertion B b


99B99B99 150182 15b01b82

99B99B99 46 00b00b46

3.13 Zero Insertion 0 0

Eg. Pic of the Field Numeric Value Edited Value 9900 12 1200

09990 456 04560


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p

3.14 Slash Insertion / /


99/99/99 150681 15/06/81

999/999/99 3254 000/032/54

3.15 Blank When Zero b


ZZZ.99 BLANK WHEN ZERO 2.5 bb2.50

999.99 BLANK WHEN ZERO 0 bbbbbb


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p

3.16 Floating Insertion

The occurrence, in multiples, of an edit symbol

The Currency symbol ($), the Minus (-) and the Plus (+)signs can appear in multiples, on the the left-hand side of aPICture

In case of the minus character (-), no sign will be insertedunless the data is negative

Eg. Pic of the Field Numeric Value Edited Value $$$$9.99 235.25 b$235.25

$$$$9.99 342 b$342.00

++++.99 -475.25 -475.25

++++.99 45 b+45.00 ----.99 -3.5 bb-3.50

----.99 3.5 bbb3.50

----.99 -382 -382.00

Chapter - 4 COBOL Verbs

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p

4.1 Data-Oriented I/O

DISPLAY

Causes the literal(s) ( any literal or an appropriate figurativeconstant ) or the contents of the specified data name(s) to bedisplayed on an output device, either a screen or a printer

Syntax

DISPLAY [ (row, col) ] {identifier-1} {,identifier-2}

{literal-1 } {,literal-2 }

Eg.DISPLAY (05,10) ENTER NAME. ENTER NAME

is displayed on the 5th row, at the 10th column


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DISPLAY SPACE

Clears the screen at the current cursor position ( the whole of thecurrent line alone )


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ACCEPT

Reads data from the console or gets data from the COBOL

predefined fields ( DATE, DAY, TIME ), and places the same in

the identifier specified

Note_01

The predefined fields DATE, DAY, TIME are not defined by the

programmer but are made available by the compiler i.e, they get

their values at the time of execution from the underlying operatingsystem


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ACCEPT

Syntax - 1

ACCEPT [ (row, col) ] {identifier-1}

Eg.

ACCEPT (05,15) WS-NAME.

The value entered for WS-NAME is accepted on the 5th row, atthe 15th column

Data input via ACCEPT is treated as if it were alphanumeric withrespect to positioning when used with (row, col)


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ACCEPT

Syntax - 2

{ DATE }

ACCEPT identifier [ FROM { DAY } ]

{ TIME }

The above syntax of ACCEPT is used to move the contents of

the COBOL predefined fields DATE, DAY and TIME to a

specified identifier


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ACCEPT

The DATE field contains the year, month and day

DATE PIC 999999

Eg.

Assume an identifier WS-TODAY with the following PICture :

01 WS-TODAY.

05 WS-T-YEAR PIC 99.

05 WS-T-MONTH PIC 99.

05 WS-T-DAY PIC 99.


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ACCEPT

ACCEPT WS-TODAY FROM DATE.

issued on June 1, 1962, will cause the content of DATE,620601

to be moved to WS-TODAY

The values of the year, month and day are stored in

WS-T-YEAR, WS-T-MONTH and WS-T-DAY Viz.,

The DAY field contains the year and the day of the year, i.e, the

Julian date

DAY PIC 99999


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ACCEPT

Eg.

Assume an identifier WS-DAY with the following PICture :

01 WS-DAY.

05 WS-T-YEAR PIC 99.

05 WS-T-DAY PIC 999.

ACCEPT WS-DAY FROM DAY.

issued on July 1, 1979, will be stored as 79183


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ACCEPT

TIME contains hours, minutes, seconds, and hundredths of asecond based on elapsed time after midnight on a 24 hour basis

TIME PIC 99999999

Eg. 8:30 P.M. is stored as 20300000

ACCEPT cannot reference a series of identifiers or literals unlikeDISPLAY i.e.,

ACCEPT WS-NUM1,WS-NUM2.

is invalid


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4.2 Data Movement

MOVE

Copies the contents of one data item ( the sending field ) to an

other data item ( the receiving field ), keeping the contents of the

first data item unchanged

Syntax

MOVE { identifier-1 } TO identifier-2 [,identifier-3]...

{ literal-1 }

Sending Field Receiving Field


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MOVE

Moving an integer

movement is from right to left non-filled higher-order

( leftmost ) integers are replaced by 0s

Moving a decimal

movement is from left to right non-filled lower-order

( rightmost ) integers are replaced by 0s

Moving a non-numeric or alphanumeric field

movement is from left to right non-filled lower-order

( rightmost ) integers are replaced by spaces


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MOVE

Eg.MOVE AMT-IN TO AMT-OUT

AMT-IN AMT-OUT

PIC 999 9(4)

VALUE 123 0123

PIC 999V99 9(4)V999

VALUE 123 45 0123 450

PIC XXX X(4)

VALUE ABC ABCb


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CDC_Covansys_Chennai

COBOL _ # 79 _Ver 2.0

MOVE

Move Corresponding

To move the contents of some or all those data items, of one group,to the corresponding identically named data items, of another group

Syntax

MOVE { CORRESPONDING } identifier-1 TO identifier-2

{ CORR }

Note_01 identifier-1 and identifier-2 should be group itemsat the same level with correspondingly relatedPICture description need not be of the same lengthand structure


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COBOL _ # 80 _Ver 2.0

MOVE

Eg.

01 WS-DATE-SYSTEM.

05 WS-YY PIC 9(2).

05 WS-MM PIC 9(2).

05 WS-DD PIC 9(2).

01 WS-DATE-PRINT.

05 WS-DD PIC Z9.

05 FILLER PIC X VALUE /.

05 WS-MM PIC Z9.


05 WS-YY PIC 99.

MOVE CORR WS-DATE-SYSTEM TO WS-DATE-PRINT.

is equivalent to the following three MOVE statements

MOVE WS-DD OF WS-DATE-SYSTEM TO WS-DD OF WS-DATE-PRINT.

MOVE WS-MM OF WS-DATE-SYSTEM TO WS-MM OF WS-DATE-PRINT.

MOVE WS-YY OF WS-DATE-SYSTEM TO WS-YY OF WS-DATE-PRINT.


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COBOL _ # 81 _Ver 2.0

4.3 Arithmetic Verbs

ADD

Elementary numeric data items alone can be added

Numeric literals alone can be added

Decimal point alignment is automatic

The target field's PICture is the deciding factor

( Internal format transformation )


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COBOL _ # 82 _Ver 2.0

ADD

Syntax 1 : ADD ... TO

ADD {identifier-1} {identifier-2}

{literal-1 } {literal-2 } ...

TO

identifier-m [ ROUNDED ]

[ identifier-n [ ROUNDED ]] ...

[ON SIZE ERROR imperative-stmt.]


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COBOL _ # 83 _Ver 2.0

ADD

Syntax 2: ADD ... TO ...GIVING

ADD {identifier-1} {identifier-2} {identifier-3}

{literal-1 } {literal-2 } {literal-3 } ...

[ TO identifier-m [ ROUNDED ] ]

GIVING identifier-m [ ROUNDED ]

[identifier-n [ ROUNDED ] ] ...



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COBOL _ # 84 _Ver 2.0

ADD

Eg.

Values After Execution

Arithmetic Statement A B C D

ADD A TO B A B+A C D

ADD A B C TO D A B C D+A+B+C

ADD A TO B C A B+A C+A D

ADD A B C A B C A+B+C

GIVING D


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COBOL _ # 85 _Ver 2.0

ADD Eg.



ADD A 15 A B A+15 A+15

GIVING C D

ADD A TO B A B B+A D

GIVING C

ADD A B TO C A B C A+B+C

GIVING D

ADD A 15 TO B A B A+B+15 A+B+15

GIVING C D


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COBOL _ # 86 _Ver 2.0

ADD

Note_01

After the TO in ADD..TO..GIVING, not more than one dataname is permitted

ADD A TO B C GIVING D

is invalid


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COBOL _ # 87 _Ver 2.0

ADD

ADD ... CORRESPONDING

To add the contents of some or all those data items, of one group, tothe corresponding identically named data items, of an other group

Syntax

ADD { CORRESPONDING }

{ CORR } identifier-1

TO identifier-2 [ ROUNDED ]


Note_01 identifier-1, identifier-2 to be group items


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COBOL _ # 88 _Ver 2.0

ADD Eg05 WS-X.

10 WS-A PIC 9(3).10 WS-B PIC 9(4).10 WS-C PIC 9(5).

05 WS-Y.10 WS-C PIC 9(5).10 WS-A PIC 9(3).10 WS-B PIC 9(4).

ADD CORR WS-X TO WS-Y.

INITIAL FINALWS-XA 2 2B 4 4

C 6 6WS-Y

A 1 3B 3 7C 5 11


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COBOL _ # 89 _Ver 2.0

SUBTRACT

Elementary numeric data items alone can be subtracted

Numeric literals alone can be subtracted





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COBOL _ # 90 _Ver 2.0

SUBTRACT

Syntax 1 : SUBTRACT ... FROM

SUBTRACT { identifier-1}

{ literal-1}

FROM { identifier-m [ ROUNDED ] }

[ identifier-n [ ROUNDED ] ] ...

[ ON SIZE ERROR imperative-stmt.]


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COBOL _ # 91 _Ver 2.0

SUBTRACT

Syntax 2: SUBTRACT ... FROM ... GIVING

SUBTRACT {identifier-1} {,identifier-2}

{literal-1 } {,literal-2 } ...

FROM {identifier-m} {literal-m }

GIVING {identifier-n [ ROUNDED ] }

[ ,identifier-o [ ROUNDED ] ] ...[ ON SIZE ERROR imperative-stmt.]


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COBOL _ # 92 _Ver 2.0

SUBTRACT

Eg.Values After Execution


SUBTRACT A A B-A C D

FROM B

SUBTRACT 15 A-15 B-15 C D

FROM A B

SUBTRACT A B A B C-(A+B) D

FROM C


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COBOL _ # 93 _Ver 2.0

SUBTRACT

Eg.



SUBTRACT A 15 A B C-(A+15) D-(A+15)

FROM C D

SUBTRACT A A B B-A D

FROM B GIVING C

SUBTRACT A B A B C C-(A+B)

FROM C GIVING D

SUBTRACT


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COBOL _ # 94 _Ver 2.0

SUBTRACT

Eg.



SUBTRACT A A B B-A B-A

FROM B GIVING C D

SUBTRACT A 15 A B B-(A+15) B-(A+15)FROM B GIVING C D

Note_01

After the FROM in SUBTRACT..FROM..GIVING,

not more than one data name is permitted

SUBTRACT A FROM B C GIVING D is invalid


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COBOL _ # 95 _Ver 2.0

SUBTRACT

SUBTRACT ... CORRESPONDING

Syntax

SUBTRACT { CORRESPONDING } identifier-1

{ CORR }

FROM identifier-2 [ ROUNDED ]


Note_01

identifier-1, identifier-2 to be group items

S C


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COBOL _ # 96 _Ver 2.0

SUBTRACT To substract the contents of some or all those data items, of one group,

from the corresponding identically named data items, of an other group

Eg.05 WS-X.

10 WS-A PIC 9(3).

10 WS-B PIC 9(4).

10 WS-C PIC 9(5).

SUBTRACT CORR WS-X FROM WS-Y.INITIAL FINAL

WS-X

A 2 2

B 4 4

C 6 6

WS-YA 1 -1

B 3 -1

C 5 -1

05 WS-Y.

10 WS-C PIC 9(5).

10 WS-A PIC 9(3).

10 WS-B PIC 9(4).


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MULTIPLY

Elementary numeric data items alone can be multiplied

Numeric literals alone can be multiplied





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MULTIPLY

Syntax 1 : MULTIPLY ... BY

MULTIPLY {identifier-1} BY identifier-2 [ROUNDED ]

{literal-1 }

[ identifier-3 [ROUNDED ]]

...



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MULTIPLY

Syntax 2: MULTIPLY ... BY ... GIVING

MULTIPLY {identifier-1} BY {identifier-2}

{literal-1 } {literal-2 }

GIVING identifier-3 [ ROUNDED ]

[ identifier-4 [ ROUNDED ]]...


MULTIPLY


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MULTIPLY

Eg.

Values After ExecutionArithmetic Statement A B C D

MULTIPLY A BY B A A*B C D

MULTIPLY A BY B C A B*A C*A D

MULTIPLY A BY B A B A*B D

GIVING C

MULTIPLY A BY 2 A A*2 A*2 D

GIVING B C

Note_01

After the BY in MULTIPLY..BY..GIVING,not more than one data name ispermitted

MULTIPLY A BY B C GIVING D is invalid

DIVIDE


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DIVIDE

Syntax 1 : DIVIDE ... INTO

DIVIDE {identifier-1} INTO identifier-2 [ ROUNDED ]

{literal-1 }

[ identifier-3 [ ROUNDED ] ]...

[ ON SIZE ERROR imperative-stmt. ]

DIVIDE


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DIVIDE

Syntax 2: DIVIDE ... BY ... GIVING

DIVIDE {identifier-1} BY {identifier-2}

{literal-1 } {literal-2 }


[ identifier-4 [ ROUNDED ]]...

[ON SIZE ERROR imperative-stmt. ]

DIVIDE


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DIVIDE

Syntax 3: DIVIDE ... BY/INTO

... GIVING

... REMAINDER

DIVIDE {identifier-1} { BY } {identifier-2}

{literal-1} {INTO} {literal-2}


REMAINDER identifier-4

[ ON SIZE ERROR imperative-stmt. ]

DIVIDE


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DIVIDE

Eg.



DIVIDE A INTO B C A B/A C/A D

DIVIDE A INTO B A B B/A D

GIVING C

DIVIDE A INTO B A B B/A B/A

GIVING C D

DIVIDE A INTO B A B Integer : Integer :

GIVING C Quotient Remainder

REMAINDER D of B/A of B/A

DIVIDE


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DIVIDE

Eg.



DIVIDE A BY B A B A/B A/B

GIVING C D

DIVIDE A BY B A B Integer : Integer :GIVING C QuotientRemainder

REMAINDER D of A/B of A/B

Note_01 After the BY/INTO in the

DIVIDE..BY/INTO..GIVING..REMAINDER, not more than one data nameis permitted

DIVIDE A BY B C GIVING D REMAINDER is invalid

COMPUTE


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COMPUTE

Combination of more than one arithmetic operation in a singlestatement

Shortens programs, avoids intermediate data names

Related expressions are made up of

Operators ( evaluated by their precedences )

Operands - Data names

Literals

COMPUTE


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COMPUTE

Syntax

COMPUTE identifier-1 [ ROUNDED ]

[identifier-2 [ ROUNDED ]]...

= Arithmetic-Expression

[ON SIZE ERROR imperative-stmt. ]

Hierarchy of execution (in terms of operators)

1. Parenthesis ( )

2. Unary - +

3. Exponentiation ** 4. Division / Multiplication *

5. Addition + Subtraction -

Within innermost parenthesis, scanning is from left to right

COMPUTE


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COMPUTE

Eg.

COMPUTE PRICE = RATE * QTY.

COMPUTE F = 1.8 * C + 32.

COMPUTE A = 2 + ( 3 * 5 ).

Chapter 5 Structured Programming

5 1 Conditional Statements

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5.1 Conditional Statements

IF statement

Passes the control between alternate paths of Statement(s)depending upon the truth of value of a test condition

Syntax

IF Condition-1

Statement-1

[ ELSE

Statement-2

[ END-IF ]].

Types of Conditions


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Types of Conditions

Simple

Class condition

Relation condition

Sign condition

Complex Abbreviated Compound

Class condition

Numeric or Alphabetic check of the operand

Numeric test cannot be done for a data item declared as alphabetic( PIC A )

Alphabetic test cannot be done for a data item declared as numeric( PIC 9 )

IF statement


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IF statement

Syntax

IF identifier IS [ NOT ] { NUMERIC }

{ ALPHABETIC }

Numeric 0 thru 9 with Sign

Alphabetic A-Z, Space

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Sign condition


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Sign condition

Determines whether the algebraic value is less than, or greaterthan, or equal to, zero

{identifier-1 } {POSITIVE }

{arith.expr.-1} IS [NOT] {NEGATIVE}

{ZERO }

Nested IFs


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Nested IFs

Eg1. Conditions

MARKS = 80 & ABOVE GRADE A= 60 - 79 GRADE B= 50 - 59 GRADE C= BELOW 50 GRADE D

Eg2. Equivalent Nested IF Statements

IF MARKS > 79MOVE A TO GRADE

ELSEIF MARKS > 59

MOVE B TO GRADE

ELSEIF MARKS > 49

MOVE C TO GRADEELSE

MOVE D TO GRADE.

Complex conditions


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Co p e co d t o s

Formed by Combining simple conditions

Nested IFsLogical connectives

Logical AND Logical ConjunctionOperators OR Logical Inclusion

NOT Logical Negation

Used for Combining simple conditionsAbbreviating conditionsNegation

Evaluation 1. Arithmetic ExpressionOrder 2. All relational operators

2.1 NOT

2.2 AND2.3 OR

Complex conditions


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Complex conditions

Note_01

Excepting the NOT operator, no two operators should be placed

consecutively,

i.e, every operator should be embedded

The logical operators NOT and OR should not

come together

Abbreviated Compound conditions


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p

With implied-subjects and relational operators

Eg1.

IF A = B AND A = C is equivalent to

IF A = B AND = C

Identical subjects are omitted in a consecutive sequence of relationalconditions

Eg2.

IF A = B AND A = C is equivalent to

IF A = B AND C

Identical subjects and relational operators are omitted in

a consecutive sequence of relational conditions

EVALUATE


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Multiple conditions may be evaluated

Syntax - 1

EVALUATE expr.-1

WHEN condition-1imperative-stmt.-1

[ WHEN condition-2

imperative-stmt.-2 ]

............. .............

[ WHEN OTHER

imperative-stmt.-n ]

[ END-EVALUATE ].

EVALUATE


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EVALUATE

Eg1.

EVALUATE COMMUTER-DRIVING-STATUS

WHEN D

MOVE DRIVER TO P-DRIVING-STATUS

WHEN R

MOVE RIDER TO P-DRIVING-STATUS

WHEN SPACES

MOVE DR/RID TO P-DRIVING-STATUS

END-EVALUATE.

EVALUATE


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Syntax 2

EVALUATE expr.-1 [ ALSO expr.-2 ]

WHEN condition-1 [ ALSO condition-2 ]

imperative-stmt.-1

[ WHEN condition-3 [ ALSO condition-4 ]imperative-stmt.-2 ]

[ WHEN condition-5 [ ALSO condition-6 ]

imperative-stmt.-3 ]

............. .............

[ WHEN OTHER

imperative-stmt.-n ]

[ END-EVALUATE ].

EVALUATE


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Eg2.

PROCEDURE DIVISION.

0001-MAIN-PARA.

EVALUATE TRUE ALSO TRUE

WHEN WS-AGE < 13 ALSO WS-SEX = M

MOVE YOUNG BOY TO WS-DESC

WHEN WS-AGE < 13 ALSO WS-SEX = F

MOVE YOUNG GIRL TO WS-DESC

WHEN OTHER

MOVE NOT YOUNG TO WS-DESCEND-EVALUATE.


EXIT.

EVALUATE


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EVALUATE

Eg3.


...........

...........


...........

...........

DATA DIVISION.WORKING-STORAGE SECTION.

01 WS-A PIC 9(1).

EVALUATE


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Eg3. (contd.)PROCEDURE DIVISION.

0001-MAIN-PARA.ACCEPT WS-A.

EVALUATE WS-A

WHEN 1

WHEN 3

WHEN 5

WHEN 7WHEN 9

DISPLAY THE GIVEN VALUE IS ODD

WHEN 2

WHEN 4

WHEN 6

WHEN 8DISPLAY THE GIVEN VALUE IS EVEN

END-EVALUATE.

0001-MAIN-PARA-EXIT.

EXIT.

EVALUATE


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Eg4.IDENTIFICATION DIVISION.

...........

ENVIRONMENT DIVISION............

DATA DIVISION.

WORKING-STORAGE SECTION.

01 WS-PERCNT PIC 9(3).

PROCEDURE DIVISION.

0001-MAIN-PARA.

ACCEPT WS-PERCNT.

EVALUATE WS-PERCNT

WHEN 50 THRU 59

DISPLAY SECOND CLASS

WHEN 60 THRU 69

DISPLAY FIRST CLASS

WHEN 70 THRU 100DISPLAY DISTINCTION

END-EVALUATE.

0001-MAIN-PARA-EXIT.

EXIT.

5.2 Internal Program Control


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g

PERFORM

Executes group of consecutive statements written elsewhere in

the program

Control departs from the normal sequence of execution to the

specified set of statements, and after completion, returns

implicitly to the statement immediately succeeding the

PERFORM statement

PERFORM


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Syntax - 1

PERFORM procedure-name

Note_01procedure-name can either be a Para-name or a Section-name

Eg1.PERFORM PARA-A

Syntax 2: THROUGH option

PERFORM procedure-name-1

{THROUGH} procedure-name-2{THRU }

Eg2.PERFORM PARA-A THRU PARA-E

PERFORM


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Syntax

3

: TIMES option

PERFORM procedure-name-1

[ THRU procedure-name-2 ]

{identifier} TIMES

{integer }

The procedure is repeatedly performed a fixed number of timesspecified by the identifier / integer

Once the PERFORM statement is initiated, any reference to theidentifier will have no effect on the number of times theprocedure is to be executed

PERFORM


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Eg3.

PERFORM PARA-A THRU PARA-C 6 TIMES.PERFORM PARA-A THRU PARA-C WS-NUM TIMES.

Syntax 4: UNTIL option

PERFORM procedure-name-1[ THRU procedure-name-2 ]UNTIL condition

The procedure is performed repeatedly as long as the

condition is False

Eg4.PERFORM PARA-A THRU PARA-D UNTIL WS-ANS = Y

PERFORM


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Syntax 5: VARYING option

PERFORM procedure-name-1[ THRU procedure-name-2 ]

{identifier-2} {identifier-3}

VARYING identifier-1 FROM {literal-1 } BY {literal-2 }

{expr.-1 } {expr.-2 }

UNTIL condition-1{identifier-5} {identifier-6}

[ AFTER identifier-4 FROM {literal-3 } BY {literal-4 }

{expr.-3 } { expr.-4 }

UNTIL condition-2

{identifier-8} {identifier-9}[ AFTER identifier-7 FROM {literal-5 } BY {literal-6 }

{expr.-5 } {expr.-6 }

UNTIL condition-3 ] ]

PERFORM


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Eg5.

PERFORM RANGE-TO-BE-EXECUTED

VARYING I FROM 1 BY 1 UNTIL I > 50

AFTER J FROM 1 BY 1 UNTIL J > 10.

The RANGE-TO-BE-EXECUTED will be performed 500 times.

With I as 1 and J varying from 1 to 10 in step of 1;

With I as 2 and J again varying from 1 to 10 in step of 1;

... and so on, till ...

With I as 50 and J again varying from 1 to 10 in step of 1.

i.e, Every time the value of I changes, J varies from 1 to 10.

5.3 Structured Programming


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g g

Enabling optimization of code by presenting the logic in themost structured way possible

Using the three kinds of control structures that facilitateStructured Programming namely

Simple Sequencing

Selection

Repetition

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Selection


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Performing an operation depending on a condition

Eg.

...........

IF WS-EOF = N

PERFORM 0002-OPEN-PARA.

...........

selection of a course of activity only if a condition holds true

Repetition


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Continually performing an operation until a certain condition holdstrue

Eg.

...........

PERFORM 0002-OPEN-PARA

UNTIL WS-EOF = Y

...........

iteration of a para (set of instructions) till a condition is true

Chapter 6 - Files6.1 File Handling

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Sequential File

Records are stored serially - one after another

Used when data volume is very high or when all the recordsstored in the file are to be processed

ENVIRONMENT DIVISION EntriesINPUT-OUTPUT SECTION.FILE-CONTROL.SELECT file-name

{DISK }ASSIGN [TO] {TAPE }

{PRINTER}[ ; ORGANIZATION IS SEQUENTIAL][ ; ACCESS MODE [IS] SEQUENTIAL][ ; FILE STATUS IS data-name-1]

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Sequential File

Chapter 6 - Files

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DATA DIVISION Entries

FILE SECTION Clauses

Clause Specifies BLOCK CONTAINS the number of records in a block

RECORD CONTAINS the maximum number of characters ina record

LABEL RECORD the presence or absence oflabel information

VALUE OF the file-attribute

DATA RECORD documents the names ofdata records of the associated file

Note_01 All the above clauses are optional

Sequential File

Chapter 6 - Files

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Eg.

FD EMP-FILE

BLOCK CONTAINS 10 RECORDS

RECORD CONTAINS 100 CHARACTERS

DATA RECORD IS FS-EMP-REC

LABEL RECORDS ARE STANDARD

VALUE OF FILE-ID IS PAYROLL.DAT.

Indexed File

Chapter 6 - Files

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Records are accessed by the value of one or more keys withinthem

ENVIRONMENT DIVISION Entries


FILE-CONTROL.SELECT file-name

ASSIGN [TO] DISK

ORGANIZATION IS INDEXED

ACCESS MODE IS [ Dynamic / Random / Sequential ]

RECORD KEY IS data-name-1[ ;ALTERNATE RECORD KEY IS data-name-2]

[ ; FILE STATUS IS data-name-3]

Indexed File

Chapter 6 - Files

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Explanations

ORGANIZATION Specifies that the file is an

INDEXED indexed file

ACCESS MODE Specifies the way the record isaccessed

Sequential in a sequential manner

Random in a random manner

Dynamic in both sequential and randommanner, in the same program

RECORD KEY Specifies which data item holds the keyvalue

ALTERNATE Allows an indexed file to be,

RECORD created with / accessed by more

KEY than one identifying key

FILE STATUS Contains the status of the operationduring the execution of a file handlingstatement; status fields length=2 bytes

Relative File

Chapter 6 - Files

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Organized in such a way that each record is identified by arelative record number

The relative record number specifies the position of the recordfrom the beginning of the file

Can be accessed either sequentially or randomly

When the access is sequential, the records are accessed in theincreasing order of their relative record numbers

When the access is random, the relative record number must bespecified and the record is accessed directly regardless of theprevious access of any other record in the file

Organization / Access Mode / Open Mode / Functions

Chapter 6 - Files

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Possible Combinations

ORGANIZATION SEQUENTIAL

( the way data is stored INDEXED

i.e, arranged ) RELATIVE

ACCESS MODE SEQUENTIAL

( the way data is accessed RANDOM

i.e, read / written ) DYNAMIC

Organization / Access Mode / Open Mode / FunctionsPossible Combinations

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Possible Combinations

OPEN MODE OUTPUT

( the way the file is opened ) INPUT

I-O

EXTEND

FUNCTIONS WRITE

( the different operations that READ

can be performed on the REWRITE

record / file ) DELETE------------

START

6.2 File-Oriented I/O

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OPEN

Initiates processing of a file

Every file must be opened before use and closed after use

For this statement to be executed, the file should not be already

open

Syntax

OPEN INPUT file-name-1

OUTPUT file-name-2I-O file-name-3

EXTEND file-name-4

OPEN

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Modes of OPENing a file

INPUT Reads records from a file

OUTPUT Writes records onto a file ( firsttime creation, irrespective of the

files existence ) I-O Reads from and writes onto a file

EXTEND Appends records to a file

Note_01Sequential file can be opened in any of the above modes

Indexed and Relative files cannot be opened in the Extend mode

OPEN

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Eg1.(To read from the sequential file DAILY-ACT and write onto thesequential file MAST-ACT)

OPEN INPUT DAILY-ACT OUTPUT MAST-ACT.

Eg2.

(To read from the sequential file DAILY-ACT and append

records onto the sequential file MAST-ACT)

OPEN INPUT DAILY-ACT EXTEND MAST-ACT.

CLOSE

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Terminates the processing of files

For this statement to be executed, the file must be open

A simple CLOSE statement releases the file from the program

Syntax

CLOSE file-name

Eg.CLOSE DAILY-ACT MAST-ACT.

Note_01It is customary to OPEN a file in the beginning of a program andCLOSE it at its end

READ

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Retrieves the next available record from an opened file

Syntax - 1

READ file-name [ RECORD ]

[ INTO identifier ]

[; AT END imperative-stmt.]

READ

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Explanations

Used for Sequential files only

Before the use of the READ statement, the file should be

opened in the INPUT or I-O mode

Eg1.

READ DAILY-ACT AT END MOVE Y TO WS-EOF.

READ

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Syntax - 2

READ file-name [ RECORD ]

[ INTO identifier ]

[ ; INVALID KEY imperative-stmt. ]

Explanations Used for Random or Dynamic access in Indexed and Relative

files only

INVALID KEY condition occurs when the record key does not

match that of an existing record

Eg2.

READ CUST-FILE INVALID KEY PERFORM ERR-RTN.

READ

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Syntax - 3

READ file-name [ NEXT ] [ RECORD ]

[ INTO identifier ]

[; AT END imperative-stmt. ]

Explanations

Beginning a sequential read from some point other than thebeginning of a file

Used for Dynamic accessing

NEXT is used to perform a Sequential read of an Indexed fileaccessed Dynamically

READ

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Eg3.

READ CUST-FILE

NEXT RECORD

AT END

MOVE NO TO ARE-THERE-RECORDS.

Note_01

READ... reads the record from the file and stores it in theidentifier(s) of the record description pertaining to the file-namespecified

READ...INTO... reads the record from the file and stores it inthe identifier(s) of the record description pertaining to the file-name specified, as well as the identifier specified with the INTOoption

WRITE

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Stores a record in a file opened in the OUTPUT mode or

EXTEND mode or in the I-O mode

Syntax - 1

WRITE record-name [ FROM identifier-1 ]

Used for sequential files

WRITE...FROM... writes the record to the file from the identifierspecified with the FROM option

Eg1.(To write records into the record EMP-REC of the sequential fileEMP-FILE)

WRITE EMP-REC.

WRITE

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Syntax - 2

WRITE record-name [ FROM identifier-1 ][ INVALID KEY imperative-stmt.-1 ]

Explanations

Used for indexed and relative files

INVALID KEY condition occurs when the record key matches thatof an existing record

Eg2.WRITE EMP-REC

INVALID KEY DISPLAY Record cannot be added.

Note_01File name should not be mentioned

REWRITE

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Replaces an existing record in a file

File should be opened in the I-O mode

Rewrite statement, preferably to be preceded by a READstatement

Syntax - 1

REWRITE record-name [ FROM identifier-1 ]

(Used for Sequential files)

Eg1.REWRITE DAILY-ACT-REC.

REWRITE

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Syntax - 2

REWRITE record-name [ FROM identifier-1 ]

[ INVALID KEY imperative-stmt. ]

Explanations

Used for Indexed files

INVALID KEY condition occurs when the record key does not

match that of an existing record

Eg2.

REWRITE EMP-REC INVALID KEY PERFORM ERR-RTN.

DELETE

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Deletes the record identified by the key given

Used only for Indexed and Relative files

Associated file to be opened in the I-O mode

Delete statement, preferably to be preceded by a READstatement

DELETE

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Syntax

DELETE file-name [ RECORD ]

[ INVALID KEY imperative-stmt. ]

INVALID KEY condition occurs when the record key does notmatch that of an existing record

Eg.DELETE CUST-FILE

INVALID KEY PERFORM ERR-ROUTINE.

START

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Starts processing records from a particular point in a file

Positions the pointer in the file to the first logical record whoserecord key satisfies the condition specified by the key phrase

Access mode to be Sequential or Dynamic

File to be opened in the I-O or Input mode

START

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Syntax

START filename [ KEY IS EQUAL TO data-name ][ INVALID KEY imperative-stmt. ]

Explanations

Data name in the KEY field must be the record key, alternatekey or any alphanumeric data item, that must be the leftmostfield in the record key

If the 'KEY IS EQUAL TO' phrase is omitted, the key for theStart verb is taken as the data name that follows the 'RECORD

KEY IS' phrase in the SELECT clause

The INVALID KEY condition arises if the condition specified bythe key phrase cannot be met

START

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Eg. Assume the following SELECT clause of an indexed file

SELECT IND-FILE ASSIGN TO DISK

ORGANIZATION IS INDEXED

ACCESS MODE IS SEQUENTIAL

RECORD KEY IS REC-KEY.

Let us further assume that the record description of the file

describes the record key in the following manner

02 REC-KEY.03 FIRST-PART PIC X.

03 FILLER PIC X(7).

START

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Now, suppose we wish to position the file at the first record

whose key begins with the letter C

MOVE C TO FIRST-PART.START IND-FILEKEY IS EQUAL TO FIRST-PART

INVALID KEY PERFORM ERROR-RTN.

This is equivalent to

MOVE C TO FIRST-PART.START IND-FILE

INVALID KEY PERFORM ERROR-RTN.

(with an assumed RECORD KEY IS REC-KEY.)

File Access Table (Access Mode Sequential)

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Sequential Indexed Relative

Open Mode

READ

I O I-O E I O I-O E I O I-O E

WRITE

REWRITE

START

DELETE

Y

Y

Y

Y

Y

Y Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Y

Organization

( q )

File Access Table (Access Mode Random)

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Open Mode

READ


WRITE

REWRITE

START

DELETE

Y Y

Y

Y

Y

Y

YY

Y

Y

Y

Organization

( )

Y

File Access Table (Access Mode Dynamic)

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Open Mode

READ


WRITE

REWRITE

START

DELETE

Y Y

Y Y

Y

Y

Y

YY

Y

Y

Y

Organization

( y )

Y Y Y Y

Chapter 7 Redefines & Renames7.1 Redefines

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Refers to the same storage area by different names with

different formats and sizes

Views a field of data with a different structure

Applies to storage area involved and not to the data that's

stored in that area

The programmer is to work with the data names which

correctly match the actual contents of the memory at a given

point

Redefines

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Syntax

level-number data-name-2 REDEFINES data-name-1

Explanations

Used in group level and elementary level

Multiple redefinition is allowed

Data names corresponding to special levels (66, 88) and those

that appear at the 01 level of the File Section cannot be redefined

Redefines Eg1.

01 WS TELEPHONE NUMBER PIC X(10)


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01 WS-TELEPHONE-NUMBER PIC X(10).01 WS-R-TEL-NUMBER REDEFINES WS-TELEPHONE-NUMBER.

05 WS-AREA-CODE PIC X(3).05 WS-CODE1 PIC X(4).05 WS-CODE2 PIC X(3).

Eg2.

01 PRODUCT-CODE.05 PLANT-CODE PIC 9(3).05 MATL-CODE PIC X(4).05 SIZE-CODE PIC 99.

01 PRODUCT-INFO REDEFINES PRODUCT-CODE.05 PLANT-LOCN PIC X(2).

05 PLANT-NUM PIC 9.05 MATL-TYPE PIC X(2).05 MATL-CAT PIC 99.05 PRODUCT-PACK PIC XX.

Redefines Eg3.


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01 WS-STORED-AREAS.

05 WS-DATE PIC X(8).05 WS-DATE-X REDEFINES WS-DATE.

10 WS-YEAR PIC 99.


10 WS-MONTH PIC 99.


10 WS-DATE PIC 99.

Eg4. ( REDEFINES with a PIC clause )

01 WS-SAMPLE.

05 WS-NAME1.

10 WS-SUR-NAME PIC X(10).10 WS-MY-NAME PIC X(10).

05 WS-NAME2 REDEFINES WS-NAME1 PIC X(20).

Redefines


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Group item redefined as an Elementary item

REDEFINES clause must immediately follow the redefined dataname

The Redefined and the Redefining data names should be ofidentical levels

The redefined and the redefining data names cannot beaccessed simultaneously

At 01 level the size of the redefining data name can be greater

than or equal to the size of the redefined data name

At other levels sizes of the redefining and redefined datanames ought to be identical

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Renames

Explanations


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Explanations

Data-name-4 to be present in Area B

Data-name-1 and data-name-3 to be names of elementary items/ group items, not items of levels 01, 66,77 or 88

Both data-name-1 and data-name-3 should not have an Occursclause, nor can they be subordinate to an item that has anOccurs clause in its data description entry

Data-name-3, if specified must follow data-name-1, in the recordand must not be one of its sub fields

Renames Eg1.

01 WS PAY


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01 WS-PAY.

05 WS-FIXED-PAY.10 WS-BASIC PIC 9(6)V99.

10 WS-DA PIC 9(6)V99.

05 WS-ADDITIONAL-PAY.

10 WS-HRA PIC 9(6)V99.

05 WS-MTHLY-INCENTIVE PIC 9(6)V99.

05 WS-DEDUCTIONS.

10 WS-PF PIC 9(6)V99.

10 WS-IT PIC 9(6)V99.

10 WS-OTHER PIC 9(6)V99.

66 WS-PAY-OTHER-BASIC RENAMES WS-DATHRU WS-MTHLY-INCENTIVE.

66 WS-IT-AND-PF RENAMES WS-PF THRU WS-IT.

Renames

Note_01

R bl REDEFINES t th t it f i f d t


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Resembles REDEFINES, except that it can form a new grouping of dataitems which combines several items

Note_02

The elementary data items to be regrouped, whether present in thesame group or across different groups, ought to be contiguous

Eg2.

01 WS-SAMPLE.

05 WS-NAME1.

10 WS-SUR-NAME PIC X(10).

10 WS-MY-NAME PIC X(10).

05 WS-NAME2 REDEFINES WS-NAME1 PIC X(20).

... REDEFINES acting as a RENAMES clause

Chapter - 8 - Tables8.1 Table

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Set of values stored in consecutive storage locations andassigned a specific data name - the table name

Structured way of defining memory areas that the program will

address

Contains homogeneous elements stored in rows and columns- the table items

A specific table item is referred to by the use of the Tablename and a Subscript

Table

Eg.

The phone-bill paid every month For One Year can be represented in COBOL as

Chapter - 8 - Tables

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p p y p

01 WS-PHONE-BILL-DETAILS.05 WS-PHONE-BILL-JAN PIC 9(6)V99.

05 WS-PHONE-BILL-FEB PIC 9(6)V99.

05 WS-PHONE-BILL-MAR PIC 9(6)V99.

05 WS-PHONE-BILL-APR PIC 9(6)V99.

05 WS-PHONE-BILL-MAY PIC 9(6)V99.

05 WS-PHONE-BILL-JUN PIC 9(6)V99.05 WS-PHONE-BILL-JUL PIC 9(6)V99.

05 WS-PHONE-BILL-AUG PIC 9(6)V99.

05 WS-PHONE-BILL-SEP PIC 9(6)V99.

05 WS-PHONE-BILL-OCT PIC 9(6)V99.

05 WS-PHONE-BILL-NOV PIC 9(6)V99.

05 WS-PHONE-BILL-DEC PIC 9(6)V99. Note_01

A cumbersome approach to store data for a period of 5 years.

COBOL simplifies this with the concept of Tables and the Occurs clause

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OCCURS Eg.

The phone-bill details will now be represented as


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p p

01 WS-PHONE-TABLE.05 WS-PHONE-BILL PIC 9(6)V99 OCCURS 12 TIMES.

... the Phone-Table with 12 values, one each for the 12 months

A simple change in the value of 12 to 60 ...

01 WS-PHONE-TABLE.

05 WS-PHONE-BILL OCCURS 60 TIMES PIC 9(6)V99.

... makes the Phone-Table hold data for a period of 5 years

The number of OCCURS clause specified in the table definition, categorizestables as

One-dimensional

Multi-dimensional

8.2 Subscripts


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Refer to an individual element in a table

Identifiers that denote the location of an entry in the table

Enclosed within a pair of parenthesis

Can be integers or data names with positive integral values

Data name used as a subscript cannot itself be subscripted

Eg. ABC(I(K)) is not allowed, because I is a subscript and is itselfnot to be subscripted

8.2.1 Values of a subscript


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Highest - the one specified by the integer in the OCCURS

clause

Lowest - implicitly assumed to be 1

Syntax 1 : One-Dimensional table

Data-name (subscript)

Syntax 2: Multi-Dimensional table

Data-name(subscript1, subscript2..)

Subscripts


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Note_01

Multi-dimensional tables are specified by using more than one

subscript ;

In a multi-dimensional table, the 1st data name with the

OCCURS clause indicates the 1st subscript, the 2nd data

name with the OCCURS clause the 2nd subscript, and so on

8.3 Multi-dimensional tables

R i l i l b i l i di id l bl i


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Require multiple subscripts to locate an individual table item

Eg1. Two-dimensional table

Table to store courses taken by a student in four semesters with six

courses per semester

01 WS-COURSE-DETAILS.

02 WS-ROLL-NO PIC 9(6).

02 WS-NAME PIC X(25).

02 WS-SEMESTER OCCURS 4 TIMES.

04 WS-COURSE OCCURS 6 TIMES.

06 WS-CN-NAME PIC XXX.

06 WS-CN-MARKS PIC 999.

Multi-dimensional tables


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To retrieve the marks of the 3rd

Course attended by a student inthe 2nd Semester

WS-CN-MARKS(2,3).

Subscript 2 selects the SEMESTER and subscript 3 selects theCOURSE within it

This being equivalent to

WS-CN-MARKS(3) IN WS-SEMESTER(2)



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Eg2. Three-dimensional tableTable to store marks scored by a student in 3 Exams under 10Courses across 20 Departments in a University

01 WS-UNIVERSITY-TABLE.05 WS-DEPT OCCURS 20 TIMES.


15 EXAM-MARKS-1 PIC 9(3).





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Equivalent three-dimensional table

01 WS-UNIVERSITY-TABLE.

05 WS-DEPT OCCURS 20 TIMES.


15 WS-EXAM-MARKS OCCURS 3 TIMES PIC 9(3).



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To retrieve the marks of a student in the 2nd Exam under the 8thCourse offered by the 12th Department

WS-EXAM-MARKS(12,8,2).

This being equivalent to

WS-EXAM-MARKS(2) IN WS-COURSE(8) IN WS-DEPT(12)



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Note_01

While accessing an item in a multi-dimensional table, the

subscript corresponding to the outermost OCCURS level is to

be specified first, followed by the one corresponding to the next

OCCURS, and so on ; the table item corresponding to the

innermost OCCURS level is to be specified as the data name

8.4 Initialization of tables using REDEFINES


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REDEFINES clause cannot appear in the same datadescription entry which contains an OCCURS clause

REDEFINES clause can appear for a group item whose

subordin

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